July 15, 2020 • 47 mins
The next Mars rover scheduled for launch is the Perseverance, which NASA hopes will be able to uncover signs that life once existed on Mars. It also will carry a helicopter-like drone. We learn about the rover, its instruments and why flying on Mars is tricky.
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Episode Transcript
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Speaker 1 (00:04):
Welcome to Text, a production from I Heart Radio. Hey there,
and welcome to tex Stuff. I'm your host, Jonathan Strickland.
I'm an executive producer with I Heart Radio and I
love all things tech Now. At the end of July
twenty NASA plans to launch a new rover on a
(00:28):
journey to Mars to continue the work of Sojournal, Spirit, Opportunity,
and Curiosity, all of which have really extended our knowledge
of the Red planet. This new rover is called Perseverance,
and it really is something special. So today we're going
to learn about the rover and its mission, and also
(00:49):
a high risk, high reward experiment called Ingenuity that is
not technically part of Perseverance, but is going along for
the ride. However, before we do that, we've got a
lot of other ground to cover, both here on Earth
and on Mars, and I want to talk a little
bit about why I chose this as a topic in
(01:11):
the first place. First is timing. Obviously, this episode should
come out a couple of weeks before the scheduled launch,
assuming everything goes well. And another reason is that these
missions often reinforce things that I find really inspiring and
even hopeful. Transporting a spacecraft to Mars, let alone landing
(01:34):
something on that planet, and then using that something to
explore and conduct scientific experiments. That's a monumental achievement. It
requires so much work, and it builds on more than
a century of discoveries and theories. It's a team effort
in which hundreds of people pull their talent and expertise
(01:56):
to pull off what when you really look at it,
seems like it should be impossible. So while we have
tons of problems we need to address here on Earth,
from dealing with the pandemic to addressing real social inequalities
and more, I look at how people have managed to
build devices that explore another planet, and it strikes me
(02:17):
that if we have the determination, we really can achieve
incredible things. We just need to apply that determination. Anyway,
here we go. As I record this, NASA has already
pushed back the launch a couple of times. So at
the moment when I'm sitting at this microphone, the scheduled
launch date is for July. Now, if that date should
(02:41):
slip for whatever reason, NASA will have a relatively narrow
window to launch or else face the reality that they
will have to shelve this project for more than two years.
So why is that. Well, let's imagine the Solar system.
Earth is the third planet out from the Sun, Mars
(03:02):
is the fourth planet out Earthen Mars revolve around the
Sun at different speeds, which means sometimes the two planets
are moving closer together and sometimes they are moving further
apart in their respective orbits. Both planets have elliptical rather
than circular orbits around the Sun, which also means there's
(03:23):
a point in the orbit where each respective planet is
closest to the Sun. This is called the parahelion. And
there's also a point in the orbit where each respective
planet is furthest from the Sun. This is the aphelian
oh and also, both of these orbits are slightly tilted
with respect to one another, complicating things even more because
(03:46):
they don't lie in the same orbital plane. These three
dimensional realities are a real pain in the neck. All
of this means that when the planets do approach one another,
they aren't in the same spots in their respective orbits
as they were the last time they got close to
one another. The closest they've been to each other in
(04:09):
recorded history is about thirty three point nine million miles apart,
or fifty four point six million kilometers, and at that distance,
it would take light about three minutes to travel from
one planet to the other, and that's the fastest stuff
in the universe. Remember, nothing goes faster than light. To
(04:30):
even have that situation, you would need the Earth to
be at its aphelian where it's furthest from the Sun,
and Mars would have to be at its parahelion, where
it is closest to the Sun, and both planets are
on the same side of the Sun. And this does
not happen frequently, at least not on human terms. That
(04:54):
thirty three point nine million mile distance happened back in
two thousand three, and according to math, that was the
closest the two planets have been for fifty thousand years. Now,
generally speaking, you do get two spans of time when
the two planets are relatively close to each other. But
because we're not just looking at orbital position, but the
(05:17):
shape of the orbits themselves, it's complicated and those are
a lot of parameters that you have to have line up.
This scenario where Earth passes between Mars and the Sun
is called opposition, and we call it opposition because from
our perspective here on Earth, Mars appears to be exactly
(05:38):
opposite where the Sun is. As the Sun is setting
at night, Mars is rising in the east, and when
Mars sets in the west during the morning hours, the
Sun is rising in the east. During opposition, Mars appears
as if it is a red star in the sky,
nearly as bright as Venus is. If it happens when
(06:01):
Mars is closest to the Sun, we call it parahelick opposition. Moreover,
the distance will begin to grow after that point as
the planets begin to move apart from each other due
to their different orbital velocities and elliptical orbits. So at
the extreme end, when the two planets are the furthest
they can possibly be from each other on either side
(06:25):
of the Sun. So the Sun is in between Earth
and Mars, they are two hundred forty nine million miles apart,
or four hundred one million kilometers. At that distance, it
would take light a whopping twenty two minutes to travel
between Mars and Earth. Not that this really matters because
(06:45):
you also have a big old Sun in the way,
so you would actually have complications. This scenario is called
a solar conjunction. Now here's the thing. Because of all
the factors that I've described here, it takes a little
more than two years to go from one opposition or
one conjunction to the next one. And actually it's about
(07:07):
twenty six months. So Earthen Mars will get the closest
they can possibly be in their respective orbits to one another,
and then it takes another twenty six months for it
to happen again. Halfway through those toy six months, you
will get to the point where they are furthest from
each other and you get the conjunction. Now, why did
(07:27):
I spend so much time talking about that, Well, it's
because NASA has to take all of this into account
when planning out emission to Mars. You want to minimize
the distance that your spacecraft has to travel in order
to get to its destination. Space travel is tough, man,
(07:49):
I mean, it requires a lot of fuel, and fuel
has mass, and mass means that you need more to
get out into space. So you can't just add more
fuel to a launch vehicle all willy nilly, because just
adding that fuel changes things. Moreover, you want to minimize
(08:09):
all the things that can go wrong while traveling from
point Earth to point Mars. One good way to do
that is to reduce the amount of travel time, which
means aiming for a time when the two planets are
going to be closest. Moreover, you don't just launch when
Earth and Mars are close, because it takes about a
hundred fifty days or so for a space vehicle to
(08:32):
get from Earth to Mars under ideal conditions, and these
planets remain in motion that whole time. It's not like
they just stop. So if you aim your rocket to
where Mars is now, Mars won't be there by the
time the rocket arrives at that location in space. The
best you can hope for is maybe a note written
(08:53):
by Mars that says something like sorry, I missed you,
And Mars is notoriously bad at writing notes, so instead
you have to aim at where Mars will be rather
than where Mars is. It's like leading a target if
you were skeet shooting right a clay pigeon is shot
up into the air, you have to lead it a
little bit if you want to hit it well. This year,
(09:15):
Mars and Earth will actually be closest, not in July,
during the scheduled launch, but in October. Specifically on October,
that's when the two plants will be thirty eight point
six million miles apart or sixty two point one million kilometers. Again,
not as close as they were back in two thousand three,
because they are not gonna be at the ideal points
(09:38):
in their respective orbits to be absolutely the closest they
can be. The last day NASA can launch a space
vehicle and take advantage of all this would be August.
If conditions prevent NASA from launching by that date, will
probably be waiting around two years before we get another opportunity.
(09:59):
This is also why if you look at the history
of missions to Mars, you'll see they hit pretty much
every two years or so. This is also why when
we talk about potential human missions to Mars, we typically
talk about a long mission that would see astronauts stay
on Mars for a couple of years, because it would
be too challenging to land on Mars, you know, goof
(10:22):
around for a week or so, and then try and
launch back to Earth because the distance would be mounting
between the two planets. We would need a mission where
we could spend an appreciable amount of time on Mars,
perhaps creating new rocket fuel on Mars itself. That way,
we don't have to carry a return trips worth of
(10:42):
fuel on our way there. That would be kind of
a deal breaker, because not only are you talking about
an enormous amount of weight, which again adds to your
concerns when you're launching the vehicle, it also represents a
massive hazard. You know, rocket fuel is dangerous stuff. But
we'll get more into that when we talk about one
(11:03):
of the experiments that Perseverance is going to do on
its mission. Interestingly, whether the launch vehicle takes off on
July or on August fifteenth, or any date in between,
the estimated date when it will enter service, that is,
when it will land on Mars and establish communications from
the surface of the red planet back here to Earth,
(11:26):
that date is the same. It's February twenty one. So
if the launch does go ahead as planned, and I
really hope it does, it's still going to be a
while before NASA can conclude whether or not the mission
was a success, or even just the initial part of
the mission is a success. Moreover All, this distance between
(11:47):
Earth and Mars means that any rover mission to Mars
requires a lot of automation, a lot of autonomy. The
distances here mean that at minimum, you're looking at around
six min minutes between when you can send a command
to a rover on Mars and when you'll get a
return signal. That's if Earthen Mars are as close as
(12:08):
they can possibly be, and usually that's not even the case.
We don't typically have that right. Most of the time.
Earth and Mars are pretty far away from each other.
When the Curiosity rover arrived on Mars on August six,
two twelve, the distance between the two plants meant it
took nearly fourteen minutes to get signals from the rover.
(12:28):
With that sort of delay, it's impossible to manually control things,
so you have to create vehicles that can land and
operate on their own. One way to do that is
to design parachutes that deploy once the spacecraft or ejected
rover reaches a certain altitude above Mars. But the Martian
atmosphere is really thin. That's going to be important later
(12:51):
in this episode two. In fact, the atmospheric pressure at
the surface of Mars is similar to what you would
find at thirty five kilometers of altitude here on Earth,
so that's a lot thirty five thousand meters above the Earth.
That air pressure is similar to the standard surface level
air pressure on Mars. To put it another way, we
(13:14):
measure atmospheric pressure and units called milla bars. Here on Earth,
the pressure at sea level is one thousand, thirteen millibars.
Mars is atmospheric pressure varies during the Martian year, but
it averages out to be between six to seven millibars.
That's it, So one thirteen here on Earth, six to seven,
(13:37):
not thousand, just six to seven on Mars. Now, since
parachutes work by forcing air into a canopy and then
effectively turning that canopy into a wing, you need atmosphere
for it to work. A parachute would be useless on
Earth's Moon, for example, because there's not enough atmosphere to
turn the parachute into a wing. Mars has an atmosphere
(13:59):
it's in, but it's there. However, it is so thin
that parachutes can typically only provide a little bit of
the breaking and support during the landing process. So NASA
has used a few different techniques to get rovers on
the surface and not have them just break apart upon
landing including housing rovers in landing craft equipped with air bags.
(14:21):
The air bags could help cushion the impact on the landing.
On Mars, the Curiosity Rover had a super awesome approach.
The rover was inside a descent vehicle, which in turn
was inside a larger uh structure. It was called the
Mars Science Laboratory or MSL, and the MSL had thrusters
on it that could make fine tune adjustments during the
(14:43):
descent phase in order to maintain the right orientation. That
also had a heat shield to absorb heat during you know,
entering the Martian atmosphere. And once it reached a certain altitude,
it deployed a parachute which helped slow its descent, and
then at a bit lower in altitude, the MSL ejected
(15:04):
a descent stage. So this was kind of a platform
with thrusters on it, and the rover was mounted inside
the platform and this would fire its thrusters, slowing its
descent further until it hovered above the Martian surface. Then
it lowered the Curiosity rover on a tether, turning the
(15:26):
descent vehicle into what they called a sky crane. The
idea was that the rover would touch down on Mars,
it would sever the tether to the descent stage, and
then the rover would be ready to go to work.
And here's the thing. This whole process from entering Mars's
atmosphere all the way to the point where the rover
touched down would take about seven minutes. But you remember
(15:50):
the delay. It was fourteen minutes of a communication delay,
So the whole process took about half the time it
takes communications to go from Mars to Earth at this
point in the two planets orbits. So the whole process
had to happen without human intervention, and not only that,
a success would mean that the rover would actually be
(16:11):
down on Mars for seven minutes before we even knew
if it had worked. And it turns out it did work,
which truly is phenomenal. And I even did a special
podcast with Tom Merritt of Daily Tech News show Fame
back when this happened in two thousand twelve. I remember
getting really emotional about this because when you consider the
(16:31):
innovation and inventiveness required to make something like this actually work,
it's really incredible. The perseverance rover will follow in curiosities
um tire tracks, and that it's going to use a
similar strategy for e d L. That stands for Intrigue,
Descent and Landing, so it's also going to use the
(16:52):
skycrane maneuver in order to land. And this time the
descent vehicle will have a couple of new tricks up
its proverbial sleeve. For example, it will have a set
of tools called Terrain relative Navigation or TRN, which will
scan the Martian terrain and allow the vehicle to change
its descent path in order to avoid any terrain that
(17:13):
looks particularly hazardous and that improves the chances of a
successful touchdown. And it's also going to have a microphone,
so we'll get to hear what it sounds like to
land on Mars. Plus if the rover wants to bust
out some David Bowie karaoke on the way down, that
microphone will come in awful handy. When we come back,
I'll talk more about the tools aboard the Perseverance, what
(17:35):
they are meant to do, and a bit about how
they work, But first let's take a quick break. Perseverance
is about the same size as its predecessor, Curiosity, which
means it's the size of a small car. It weighs
(17:56):
a bit more than Curiosity as well. UH has a
mass of one thousands, so here on Earth it weighs
two thousand, two hundred sixty pounds. If we don't include
the rover's arm. The rover measures about ten ft long
by nine ft wide, and it's seven ft tall. That's
(18:18):
a three meters by two point seven meters by two
point two meters, so it's a pretty big rover. Before
we get into the super techy stuff and the goals
of perseverance, let's look at some other related things. For example,
the launch vehicle perseverance will depend upon the launch of
an Atlas five one launch vehicle from the United Launch Alliance.
(18:44):
This is a two stage rocket essentially, and it stands
fifty eight meters or one ft tall when the payload
is attached to the top. Fully fueled. With the payload
in place, the full launch vehicle weighs five hundred thirty
one thousand kilogram ms or one point one seven million pounds.
The five for one designation tells us a lot about
(19:07):
the launch vehicle, as it turns out, so that five
and five four one refers to the diameter of the
fairing that holds the payload in place with the launch vehicle.
So in this case, the spacecraft that will hold the
perseverance and this fairing is five meters in diameter. That's
what that five means. So what's the four and five
(19:28):
or one means? Well, that tells us how many solid
fuel rocket boosters are part of this launch vehicle. So
there are four solid fuel rocket boosters, and the one
tells us how many rocket engines are in the second stage.
This is called the center and there are single engine
centaurs and dual engine centaurs, so this one is a
(19:49):
single engine centaur. The first stages rocket engine is called
the r D one eight and this one was made
in Russia. The engine burn is the fuel made of
kerosene and liquid oxygen. The second stage centaur uses fuel
made of liquid hydrogen and liquid oxygen, which must be
kept at very low temperatures to remain liquid, and for
(20:12):
that reason they are called cryogenic propellants. So at launch,
the boosters and rocket engine for the first stage will
carry the vehicle up to a certain altitude and that's
where the first stage will separate from the rest of
the vehicle. The first stage will fall back to Earth.
The second stage ignites and propels the spacecraft out to
its trajectory to bring it on an intercept course with Mars,
(20:35):
and then it separates from the launch vehicle, and then
Perseverance aboarded spacecraft will be on its way on its
very long trip out to Mars. So, assuming everything goes
as planned, Perseverance will touch down on Mars in February
twenty twenty one thanks to the skycrane maneuver. If things
don't go as planned, uh, I mean, I don't know,
(20:57):
I mean if it if it doesn't launch Biogus fifteen,
there's a real question of whether or not the project
can be put on hold for two years. And if
something goes wrong, well, I guess you know, the mission
scrapped and stuff can go wrong because space, as it
turns out, is super hard. I mean, like that thing
is trying to kill you. But let's say it all
goes to plan and the rover makes it to Mars.
(21:19):
What is it going to do when it's there. Well,
NASA says the mission will last at least one year
on Mars. That is one Martian year. That's equal to
six hundred eighty seven Earth days, so nearly two full
Earth years. If the mission is a success, we may
well see the experiments stretch on much longer than that.
(21:42):
The Opportunity mission was only intended to last for ninety days,
but it was able to continue for nearly fifteen years.
But what is Perseverance going to do when it's up
there all that time. The overall program Perseverance is part
of it is called the Mars Exploration Program or m
e P, and one of the primary goals of m
(22:04):
e P is to look for signs of life, most
likely signs that life once existed on Mars thousands and
thousands and millions of years ago. But boy, it really
would be cool if we found evidence of microbial life
on Mars today. NASA has laid out four science objectives
that Perseverance will pursue in an effort to further this goal.
(22:28):
The four objectives are looking for habitability, that is, seeking
out areas that could have supported microbial life in the
ancient past, seeking bio signatures, so looking for evidence that
microbial life actually did exist in these habitable environments, such
as in signs and the rocks themselves. Cashing samples. This
(22:50):
is all about collecting and analyzing rock and soil samples,
and preparing for humans, which will take on the super
cool challenge of producing oxygen on Mars. Now we'll dive
into these more in a moment, but in addition to
the four primary objectives, Perseverance will also study the seasons
on Mars and how weather patterns change, including stuff like
(23:13):
dust storms. It will be building on our understanding of Mars,
which will be critical if we ever do actually want
to send astronauts there or colonists. So a lot of
what Perseverance will be doing sets the stage for future
missions with actual humans on Mars. NASA is going about
this in a very methodical way. And I say that
(23:34):
because I'm sure at least some of you remember the
private organization called Mars One that had the stated goal
of establishing a permanent colony on Mars. The Mars One
Plan was to create habitats on the planet, or technically
under the surface of the planet, because Mars doesn't have
the same protective measures as Earth does when it comes
(23:57):
to deflecting harmful radiation and articles from stuff like you know,
the Sun, and the Mars One Plan didn't have anything
in it about coming back to Earth. This was a
one way trip. The organization was founded in two thousand eleven.
It attempted to raise money from investors and through an
application process in which people would vie to be considered
(24:21):
as astronauts for this mission, but it ultimately didn't go anywhere,
and that, by the way, is a big strike against
space exploration. Typically in space exploration, you gotta go somewhere, right,
So the owners ended up liquidating the organization in early
two thousand nineteen. Some people think the whole thing was
(24:41):
nothing more than a scam. Now. I don't know if
the founders intentionally set out to mislead people or not,
but I was certainly skeptical of the efforts, as it
seemed to be taking a lot of assumptions as concrete facts,
and that's dangerous. Now, that's not the case with NASA's approach.
It's always dangerous. Space is always dangerous, but they're not
(25:05):
taking assumptions as fact. Their approach is to build a
foundation of knowledge upon which future missions will continue to build,
with the hopeful goal of one day having astronauts themselves
set foot on Mars. But NASA is not quite as
cavalier as the Mars one plan. So let's start with
(25:25):
the analysis of Mars and the search for life. Then
we'll move on to the components that have more to
do with laying the groundwork for human exploration in the
distant future. And then we have the issue of ingenuity
to talk about, but that's for a kicker at the end.
One of the things Perseverance has that Curiosity doesn't have
(25:46):
is a drill. So Perseverance will be able to drill
into soil and rocks on Mars to collect samples for analysis.
The drill is on the rover's big arm, but a
smaller arm actually plays a part in the two. It
can supply sample tools to the drill, so as the
drill is working, the soil and rock that it ends
(26:08):
up removing can be collected in one of these tubes.
Then the little arm can take that tube full of
material and store it back on the rover. At the
end of this the rover will store certain rocks and
soil samples, very specific ones, ones that the team back
on Earth have identified as being particularly interesting. It'll store
(26:29):
a collection of these in a cash that's intended for
later retrieval, and the idea that these would someday be
returned to Earth. I'll talk about that at the end
of this episode. Now, this mission itself lacks the ability
to come back. There's nothing about the Perseverance mission that
allows them to return to Earth, so this will have
(26:49):
to wait for a future mission. The plan is to
collect at least twenty samples. However, the rover does have
enough equipment to collect as many as forty three. Now.
Along with the forty three sample tubes, the rover will
also carry five special tubes called witness tubes. The purpose
for these is to make sure that the stuff Perseverance
(27:11):
is finding is actually coming from Mars. See. One of
the risks of this kind of exploration is that our
equipment might unwittingly introduce stuff from Earth into Mars, and
if that stuff happens to be organic in nature, like
it happens to be the same as an organic marker,
it could mean that any evidence we find that suggests
(27:33):
life was once on Mars could actually be a total
red herring, because it could turn out that the organic
material actually came from Earth in the first place and
was unwittingly released on Mars. It's kind of like one
of those movies where you've got a crooked cop who
drops a bag of incriminating material right in front of
a suspect and says, well, why do we have here?
(27:54):
Looks like we've got some evidence, except, of course, the
rover wouldn't be doing this on purpose. It's not scuzzy,
you know, bad cop type. The witness tubes can capture
contaminants and allow researchers on Earth to discern whether the
stuff that was collected on Mars actually is totally Martian
in origin, or if it has some contaminants that were
(28:17):
accidentally brought by Perseverance, So they can do that if
those tubes ever find their way back to Earth, so
this is also part of that long term deal. The
rover will hermetically seal all the sample tubes and store
it temporarily in the rover itself, but eventually the team
will determine a location where the rover will store all
(28:39):
of these tubes called the Sample Cash Depot, and this
is where they will stay until a future mission can
pick them up and bring them back home to Earth.
There are seven major scientific instruments aboard the Perseverance, so
let's go through those. First up is the mass cam Z,
a camera mounted on a vertical gold pole, thus the
(29:01):
term mast and this is near the center of the rover.
The camera has a panoramic camera as well as a
stereoscopic imaging camera, so it can take really wide shots
of the horizon, or it can use its stereoscopic lenses
to capture three dimensional images on Mars's surface. Now, not
only will this camera be used to take lovely photos
(29:22):
and to help the team on Earth determine where to
send the rover, it also can help engineers back on
Earth learn more about the mineralogy of Mars' surface. Next,
we have the Supercam, which by day is a mild
mannered photographer for the Daily Planet. Wait, sorry, no, I
I meant that it's a camera intended to analyze the
(29:43):
chemical composition of stuff on Mars at a distance. Then
you've got pixel p I x L that actually stands
for Planetary Instrument for X ray litho chemistry. And if
you're wondering what litho chemistry is, you're not alone, because
I don't think I have ever seen that word ever
(30:03):
before I started researching this episode. In fact, as I
was researching the term, the only time I was seeing
any instance of litho chemistry as a word was in
reference to pixel itself, and this annoys me. I mean, NASA,
if you're going to use cute acronyms for your tools,
you can't just get around the inconvenience of not having
(30:25):
the correct letters by making up a word. But let's
suss it out. So litho means stone. Now it all
makes sense, right. Litho chemistry means the chemical makeup of
stones on Mars in this case, And this device uses
X rays in order to really study the stones around
(30:47):
the rover. X rays have a shorter wavelength and carry
way more energy than the visible light spectrum does. The
pixel has a spectrometer, which is a device that measures
the spectral components of something. And no, this isn't about
specters like ghosts or something. This is more about a spectrum,
(31:07):
you know, like the spectrum of electromagnetic radiation or the
spectrum of visible light. So they measure a continuous variable
of some sort, and the pixel measures the electromagnetic radiation
that's reflected off of various materials on Mars, which then
tells us more about what those materials are made of.
Then we've got these scanning habitable environments with Raymond luminescence
(31:31):
for organics and chemicals, and this is a really cute acronym.
The acronym is share Lock. This is another spectrometer, but
rather than X rays, this one uses an ultra violet laser. Now,
like X rays, ultra violet waves are shorter in wavelength
and higher in energy than the visible spectrum, but they
(31:52):
don't penetrate as far as X rays do. The spectrometer
will also measure the composition of materials on Mars and
search for the press of organic compounds. It also has
a high resolution camera for microscopic imaging, so that's pretty neat.
Then there's the Radar Imager for Mars's Subsurface Experiment or
rim FACTS. This one uses a radar system that can
(32:15):
penetrate the ground and give what NASA calls a quote
centimeter scale resolution of the geologic structure of the subsurface
end quote super nifty. Then there's one more scientific experiment
aboard the Perseverance that we need to talk about, as
well as ingenuity, something I haven't really covered yet, but
(32:37):
keep teasing, but we'll get back to that after we
take another short break. The last of the major experiments
aboard the Perseverance is the Mars Oxygen Institute Resource Utilization
Experiment or MOXI. What a rate acronym. Now, this experiment
(33:02):
will attempt to generate oxygen from the carbon dioxide that's
in Mars's atmosphere. See Here on Earth, c O two
makes up about point zero four percent of our atmosphere,
and that's it, and honestly, that's enough. C O two
is a greenhouse gas. In fact, out of all the
greenhouse gases that humans release in our atmosphere, CEO two
(33:24):
makes up eighty one point three per cent of them.
So a little c O two can go a long
way when it comes to the greenhouse effect. But Mars's
atmosphere is a totally different story. There, c O two
is a major player. It makes up of Mars's atmosphere. Oxygen,
by contrast, makes up a tiny point one three of
(33:47):
Mars's atmosphere. Here on Earth, it's twenty one of our atmosphere. Now,
it's incredibly obvious that we humans need oxygen, and it
stands to reason that would be way better if we
could produce is the oxygen we need on Mars while
you know, we're actually on Mars, as opposed to bringing
everything with us, everything we decide we need to bring
(34:09):
we have to launch off the Earth, and launching stuff
is expensive and it's risky, so it would be better
if we could create all the stuff we need while
we're already on Mars. On top of that, besides breathing,
we need oxygen as a component for rocket fuel, so
using the resources of Mars to create fuel would be
a huge deal. Again, we wouldn't have to send our
(34:31):
return trips worth of fuel out on the launch. That
would be enormous. Now, Moxie isn't going to terraform Mars.
It's a small scale experiment, more like a proof of concept.
It will take c O two from Mars's atmosphere and
convert it into oxygen and carbon monoxide through an electrochemical process.
(34:54):
So Moxie pulls in air from the environment. It will
pass that air through a filter and then pressure rize
the c O two so that it's approximately one atmosphere
in pressure. That is one Earth atmosphere in pressure, which
is much greater pressure than what you would find in Mars'
own atmosphere. The CEO two then goes to a solid
(35:14):
oxide electrolyzer or s o x E. The electrochemical process
does the separating at a temperature of eight hundred degrees celsius,
so things get pretty toasty. There are gas preheating components.
There's also an exhaust cooling component. All of this is
really important for moxy to operate, but also it's important
(35:35):
to cool the exhaust in order to protect the other
experiments that are aboard the Perseverance. The exhaust also has
to pass through a filter before it can be vented
back out to the Martian atmosphere. Now why is that, Well,
it gets back to those contaminants I mentioned earlier. We
have a responsibility to limit the sort of contaminants we
could introduce to another planet, and there's actually an official
(35:58):
policy about this is called the Planet Erry Protection Requirements. Now,
assuming Moxi's experiments are successful, we might see NASA and
other organizations create larger implementations of this same technology to
make a significant amount of oxygen from the Martian atmosphere.
And that will be a big step in the direction
to send people to Mars, as it will give those
(36:19):
people an important component for making the rocket fuel needed
to return back here to Earth. And now finally it's
time to talk about ingenuity, a high risk, high reward
experiment it's high risk because no one really knows yet
if it's actually gonna work. It's high reward because if
it does well, we'll have an incredible experience that we
(36:40):
can build upon. So what the heck is Ingenuity? It's
a helicopter. Yeah, Perseverance is bringing along with it a
helicopter to Mars, so you can get to the chopper
and get to Mars at the same time, thus fulfilling
two different Arnold schwarz Senegger film plots simultaneously. It's never
(37:04):
been done before. Now let's get more specific. When I
say helicopter, I don't mean the sort of flying vehicle
that carries people around here on Earth. This is more
like a drone. It's a very small aircraft. It's autonomous,
which yeah, I would have to be. There's no way
you can fly this thing via remote control back here
(37:25):
on Earth. It would crash and then you'll be waiting
fifteen minutes or whatever in order to find out about it.
The Ingenuity has a mass of one point eight kgrams,
so here on Earth it weighs four pounds, and it
makes sense that it needs to be lightweight because the
Martian atmosphere is so thin. Now, Remember, heavier than air,
(37:46):
aircraft need to generate lift, and you can think of
lift as a force that presses up on the underside
of a wing or, in the case of a helicopter,
the underside of its rotors, which really a rotor is
just a wing that moves in a circle. This force
has to be strong enough to counteract the weight of
the object in order to get off the ground. If
(38:09):
the gravity of Mars were the same as that of Earth,
this would be super hard to do because the atmosphere
is so thin you would struggle to generate enough lift
to counteract the weight of the flight vehicle. But gravity
on Mars is also not as strong as it is
here on Earth. It's actually about one third of Earth's
gravity a little more than that. So yeah, you've got
(38:32):
a thin atmosphere, but you also have less gravity and
therefore less weight to worry about. So your mass stays
the same because gravity does not affect how much mass
something has, but your weight is different. So while the
helicopter gadget weighs around four pounds here on Earth, on Mars,
it's going to be closer to a pound and a half.
Now I would still have one pot eight krams of
(38:54):
mass because mass doesn't change, but that mass would weigh
the same as an object that has just point six
eight kilograms of mass here on Earth. So if somehow
you were able to take an earth point six eight
kilograms and put it against this thing while it's on Mars,
the scales would balance out. Now, considering the rotors on
(39:17):
this thing, I'm actually really impressed they were able to
get the weight that low because each rotor, and there
are two of them, measures four feet or one point
two meters in lengths Now, just remember that these rotors
are mounted in the center. So the helicopter also has
solar panels. Those are going to be used to charge
the onboard battery. It has a wireless communication system that
(39:40):
allows engineers on Earth to relay commands to the helicopter
via the rover. So in this case, the engineers could
give pretty general commands, such as how long the helicopter
would operate or how high it was to fly. But
then the helicopter has to do all the actual flying
on its own. There will be no steering this thing
due to that community cation lag. The helicopter has inertial sensors,
(40:04):
so it can tell what it's orientation is whether it's
upright or not. It's also got a laser altimeter, so
this is essentially a laser range finder, so it shoots
a laser at the ground. It essentially measures the amount
of time it takes for the laser to go out
from the laser range finder, hit the ground, and come
(40:24):
back up and hit a sensor, and from that it
can determine how high up it is. It's also got
two cameras on board. One of them can take color
images and the other one can only take black and
white images. And it's got some heating components inside of it,
which is important because it needs to stay in an
operational temperature even during the Martian night. Uh the average
(40:45):
temperature on Mars is about minus sixty degrees celsius, though
in the daytime during the Martian summer, if you happen
to be near the equator, you might reach a high
of up to twenty degrees celsius. That's twenty degrees positive.
So there is a really wide variation in temperatures on
the planet. That's something else that we would have to
(41:07):
prepare for if we were to ever actually, you know,
go there. Now, NASA has made it clear that this
aircraft is considered a quote completely independent of the Mars
twenty twenty science mission end quote, which is why the
ingenuity doesn't really show up when you look at the
breakdown of experiments that are aboard the Perseverance. It's also
described as a quote demonstration of technology end quote. That
(41:31):
means ingenuity isn't going to be relied upon to deliver
any you know, scientific data about Mars. It's really meant
to give us an idea if the powered flying device
is a viable approach on Mars. It's also meant to
prove that the manchaization of technology is necessary to allow
for this will actually work. And if it does work,
(41:51):
then that means we could see all sorts of flying
drones deployed to Mars in the future to do stuff
like map out areas or survey regions that are to
treacherous for rovers to manage, or perform other scientific experiments. Now,
my hope is that all of these experiments teach us
a lot more about our neighbor planet, and that with
this information we can plot out further missions. And I
(42:14):
think it would be truly remarkable if I were to
see people land on Mars within my lifetime, and as always,
there are opportunities for the things we learned in the
technology we developed to make all this possible to benefit
us in other ways. One of the coolest things about
space exploration that's not really about the exploration itself, is
(42:37):
that all the technology that was once created as a
necessity in order to achieve mission goals has kind of
found its way into our daily lives and other implementations.
We often see unanticipated benefits as byproducts, and so I
think it's always a good thing for us to push
back our boundaries of ignorance. You never know what sort
of things you're gonna uncover along the way. As for
(42:57):
future missions, there are a couple more that I can
mention briefly. One is a part of a mission that
is called the Exo Mars Program. This one is actually
led by the European Space Agency and the ros Cosmos
State Corporation. The plan is to launch a rover which
would not be that much different from Curiosity and Perseverance
(43:19):
in twenty twenty two, again two years apart. This one
will be called the Rosalind Franklin, named after the British chemist.
NASA is contributing some of the UH components that are
going to be used in some of the scientific instruments
as part of this rover. The rover's mission is very
similar to that of Perseverance, primarily looking for evidence that
(43:41):
life could have existed on Mars in the ancient past.
Another mission is the aforementioned plan to retrieve the samples
that Perseverance is going to collect, assuming its mission is successful.
This one is a more long term plan because of
the complexities of getting two and back from Mars. So
(44:03):
going from Earth to Mars and back again, really we've
only managed one way trip so far, this would be
a lot harder. The current proposed timeline would have a
launch of the initial vehicle, the Sample Return Lander, in
July twenty six, which would actually touch down on Martian
soil in August twenty eight. Now that's an unusually long
(44:26):
travel time and honestly I don't know all the reasons
for that. But the lander will have its own mini
rover provided by the European Space Agency, and this rover
will go and fetch the stored samples that Perseverance had gathered.
In one it will bring those samples to a rocket
that is carried aboard the Sample Return Lander, and the
(44:48):
rocket will blast off, the first time in history that
we will have launched a rocket from another planet, and
it will then send the payload to rendezvous with another
spacecraft in orbit around Mars. That spacecraft is called the
Earth Return Orbiter, and it will actually launch from Earth
separately from the lander. It would launch in September, a
(45:10):
couple of months after the lander has launched, but it
will arrive in orbit around Mars by October, several months
before the lander touches down. The Sample Return container from
the rocket will separate, it will dock with the Earth
Return Orbiter, and then the orbiter would prepare for the
trip back home once Earth and Mars were lined up again,
(45:34):
and the estimated return date would be sometime in twenty
thirty one. So if everything goes well, it's going to
take more than a decade to get those Martian rocks
and soil back here on Earth for analysis. Man, this
stuff is hard, but super interesting, and that wraps up
this episode about perseverance. It remains to be seen if
(45:57):
the launch is going to be a success. I certainly
hope it is. I plan on watching it on July,
assuming that the launch goes ahead as planned, and I'm
wishing everyone all the best. This is a very exciting
kind of mission, and as I said before, I find
it personally very inspiring that we can achieve something that
(46:18):
is so difficult to do, and if we can do that,
then we can tackle some of these problems that are
enormous here on Earth that seem impossible. But it may
just be that we're not dedicating the effort and the
resources necessary to really change things. And I think that
that is something we could entirely do if we set
(46:38):
our minds to it. If you guys have future suggestions
for tech Stuff episodes, or rather suggestions for future tech
Stuff episodes, either way, the only way I know about
it is if you send them to me, So send
them to me on Twitter. To handle for the show
is text Stuff H s W and I'll talk to
you again really soon Y. Text Stuff is an I
(47:05):
Heart Radio production. For more podcasts from I Heart Radio,
visit the I Heart Radio app, Apple Podcasts, or wherever
you listen to your favorite shows.
Welcome to Text, a production from I Heart Radio. Hey there,
and welcome to tex Stuff. I'm your host, Jonathan Strickland.
I'm an executive producer with I Heart Radio and I
love all things tech Now. At the end of July
twenty NASA plans to launch a new rover on a
(00:28):
journey to Mars to continue the work of Sojournal, Spirit, Opportunity,
and Curiosity, all of which have really extended our knowledge
of the Red planet. This new rover is called Perseverance,
and it really is something special. So today we're going
to learn about the rover and its mission, and also
(00:49):
a high risk, high reward experiment called Ingenuity that is
not technically part of Perseverance, but is going along for
the ride. However, before we do that, we've got a
lot of other ground to cover, both here on Earth
and on Mars, and I want to talk a little
bit about why I chose this as a topic in
(01:11):
the first place. First is timing. Obviously, this episode should
come out a couple of weeks before the scheduled launch,
assuming everything goes well. And another reason is that these
missions often reinforce things that I find really inspiring and
even hopeful. Transporting a spacecraft to Mars, let alone landing
(01:34):
something on that planet, and then using that something to
explore and conduct scientific experiments. That's a monumental achievement. It
requires so much work, and it builds on more than
a century of discoveries and theories. It's a team effort
in which hundreds of people pull their talent and expertise
(01:56):
to pull off what when you really look at it,
seems like it should be impossible. So while we have
tons of problems we need to address here on Earth,
from dealing with the pandemic to addressing real social inequalities
and more, I look at how people have managed to
build devices that explore another planet, and it strikes me
(02:17):
that if we have the determination, we really can achieve
incredible things. We just need to apply that determination. Anyway,
here we go. As I record this, NASA has already
pushed back the launch a couple of times. So at
the moment when I'm sitting at this microphone, the scheduled
launch date is for July. Now, if that date should
(02:41):
slip for whatever reason, NASA will have a relatively narrow
window to launch or else face the reality that they
will have to shelve this project for more than two years.
So why is that. Well, let's imagine the Solar system.
Earth is the third planet out from the Sun, Mars
(03:02):
is the fourth planet out Earthen Mars revolve around the
Sun at different speeds, which means sometimes the two planets
are moving closer together and sometimes they are moving further
apart in their respective orbits. Both planets have elliptical rather
than circular orbits around the Sun, which also means there's
(03:23):
a point in the orbit where each respective planet is
closest to the Sun. This is called the parahelion. And
there's also a point in the orbit where each respective
planet is furthest from the Sun. This is the aphelian
oh and also, both of these orbits are slightly tilted
with respect to one another, complicating things even more because
(03:46):
they don't lie in the same orbital plane. These three
dimensional realities are a real pain in the neck. All
of this means that when the planets do approach one another,
they aren't in the same spots in their respective orbits
as they were the last time they got close to
one another. The closest they've been to each other in
(04:09):
recorded history is about thirty three point nine million miles apart,
or fifty four point six million kilometers, and at that distance,
it would take light about three minutes to travel from
one planet to the other, and that's the fastest stuff
in the universe. Remember, nothing goes faster than light. To
(04:30):
even have that situation, you would need the Earth to
be at its aphelian where it's furthest from the Sun,
and Mars would have to be at its parahelion, where
it is closest to the Sun, and both planets are
on the same side of the Sun. And this does
not happen frequently, at least not on human terms. That
(04:54):
thirty three point nine million mile distance happened back in
two thousand three, and according to math, that was the
closest the two planets have been for fifty thousand years. Now,
generally speaking, you do get two spans of time when
the two planets are relatively close to each other. But
because we're not just looking at orbital position, but the
(05:17):
shape of the orbits themselves, it's complicated and those are
a lot of parameters that you have to have line up.
This scenario where Earth passes between Mars and the Sun
is called opposition, and we call it opposition because from
our perspective here on Earth, Mars appears to be exactly
(05:38):
opposite where the Sun is. As the Sun is setting
at night, Mars is rising in the east, and when
Mars sets in the west during the morning hours, the
Sun is rising in the east. During opposition, Mars appears
as if it is a red star in the sky,
nearly as bright as Venus is. If it happens when
(06:01):
Mars is closest to the Sun, we call it parahelick opposition. Moreover,
the distance will begin to grow after that point as
the planets begin to move apart from each other due
to their different orbital velocities and elliptical orbits. So at
the extreme end, when the two planets are the furthest
they can possibly be from each other on either side
(06:25):
of the Sun. So the Sun is in between Earth
and Mars, they are two hundred forty nine million miles apart,
or four hundred one million kilometers. At that distance, it
would take light a whopping twenty two minutes to travel
between Mars and Earth. Not that this really matters because
(06:45):
you also have a big old Sun in the way,
so you would actually have complications. This scenario is called
a solar conjunction. Now here's the thing. Because of all
the factors that I've described here, it takes a little
more than two years to go from one opposition or
one conjunction to the next one. And actually it's about
(07:07):
twenty six months. So Earthen Mars will get the closest
they can possibly be in their respective orbits to one another,
and then it takes another twenty six months for it
to happen again. Halfway through those toy six months, you
will get to the point where they are furthest from
each other and you get the conjunction. Now, why did
(07:27):
I spend so much time talking about that, Well, it's
because NASA has to take all of this into account
when planning out emission to Mars. You want to minimize
the distance that your spacecraft has to travel in order
to get to its destination. Space travel is tough, man,
(07:49):
I mean, it requires a lot of fuel, and fuel
has mass, and mass means that you need more to
get out into space. So you can't just add more
fuel to a launch vehicle all willy nilly, because just
adding that fuel changes things. Moreover, you want to minimize
(08:09):
all the things that can go wrong while traveling from
point Earth to point Mars. One good way to do
that is to reduce the amount of travel time, which
means aiming for a time when the two planets are
going to be closest. Moreover, you don't just launch when
Earth and Mars are close, because it takes about a
hundred fifty days or so for a space vehicle to
(08:32):
get from Earth to Mars under ideal conditions, and these
planets remain in motion that whole time. It's not like
they just stop. So if you aim your rocket to
where Mars is now, Mars won't be there by the
time the rocket arrives at that location in space. The
best you can hope for is maybe a note written
(08:53):
by Mars that says something like sorry, I missed you,
And Mars is notoriously bad at writing notes, so instead
you have to aim at where Mars will be rather
than where Mars is. It's like leading a target if
you were skeet shooting right a clay pigeon is shot
up into the air, you have to lead it a
little bit if you want to hit it well. This year,
(09:15):
Mars and Earth will actually be closest, not in July,
during the scheduled launch, but in October. Specifically on October,
that's when the two plants will be thirty eight point
six million miles apart or sixty two point one million kilometers. Again,
not as close as they were back in two thousand three,
because they are not gonna be at the ideal points
(09:38):
in their respective orbits to be absolutely the closest they
can be. The last day NASA can launch a space
vehicle and take advantage of all this would be August.
If conditions prevent NASA from launching by that date, will
probably be waiting around two years before we get another opportunity.
(09:59):
This is also why if you look at the history
of missions to Mars, you'll see they hit pretty much
every two years or so. This is also why when
we talk about potential human missions to Mars, we typically
talk about a long mission that would see astronauts stay
on Mars for a couple of years, because it would
be too challenging to land on Mars, you know, goof
(10:22):
around for a week or so, and then try and
launch back to Earth because the distance would be mounting
between the two planets. We would need a mission where
we could spend an appreciable amount of time on Mars,
perhaps creating new rocket fuel on Mars itself. That way,
we don't have to carry a return trips worth of
(10:42):
fuel on our way there. That would be kind of
a deal breaker, because not only are you talking about
an enormous amount of weight, which again adds to your
concerns when you're launching the vehicle, it also represents a
massive hazard. You know, rocket fuel is dangerous stuff. But
we'll get more into that when we talk about one
(11:03):
of the experiments that Perseverance is going to do on
its mission. Interestingly, whether the launch vehicle takes off on
July or on August fifteenth, or any date in between,
the estimated date when it will enter service, that is,
when it will land on Mars and establish communications from
the surface of the red planet back here to Earth,
(11:26):
that date is the same. It's February twenty one. So
if the launch does go ahead as planned, and I
really hope it does, it's still going to be a
while before NASA can conclude whether or not the mission
was a success, or even just the initial part of
the mission is a success. Moreover All, this distance between
(11:47):
Earth and Mars means that any rover mission to Mars
requires a lot of automation, a lot of autonomy. The
distances here mean that at minimum, you're looking at around
six min minutes between when you can send a command
to a rover on Mars and when you'll get a
return signal. That's if Earthen Mars are as close as
(12:08):
they can possibly be, and usually that's not even the case.
We don't typically have that right. Most of the time.
Earth and Mars are pretty far away from each other.
When the Curiosity rover arrived on Mars on August six,
two twelve, the distance between the two plants meant it
took nearly fourteen minutes to get signals from the rover.
(12:28):
With that sort of delay, it's impossible to manually control things,
so you have to create vehicles that can land and
operate on their own. One way to do that is
to design parachutes that deploy once the spacecraft or ejected
rover reaches a certain altitude above Mars. But the Martian
atmosphere is really thin. That's going to be important later
(12:51):
in this episode two. In fact, the atmospheric pressure at
the surface of Mars is similar to what you would
find at thirty five kilometers of altitude here on Earth,
so that's a lot thirty five thousand meters above the Earth.
That air pressure is similar to the standard surface level
air pressure on Mars. To put it another way, we
(13:14):
measure atmospheric pressure and units called milla bars. Here on Earth,
the pressure at sea level is one thousand, thirteen millibars.
Mars is atmospheric pressure varies during the Martian year, but
it averages out to be between six to seven millibars.
That's it, So one thirteen here on Earth, six to seven,
(13:37):
not thousand, just six to seven on Mars. Now, since
parachutes work by forcing air into a canopy and then
effectively turning that canopy into a wing, you need atmosphere
for it to work. A parachute would be useless on
Earth's Moon, for example, because there's not enough atmosphere to
turn the parachute into a wing. Mars has an atmosphere
(13:59):
it's in, but it's there. However, it is so thin
that parachutes can typically only provide a little bit of
the breaking and support during the landing process. So NASA
has used a few different techniques to get rovers on
the surface and not have them just break apart upon
landing including housing rovers in landing craft equipped with air bags.
(14:21):
The air bags could help cushion the impact on the landing.
On Mars, the Curiosity Rover had a super awesome approach.
The rover was inside a descent vehicle, which in turn
was inside a larger uh structure. It was called the
Mars Science Laboratory or MSL, and the MSL had thrusters
on it that could make fine tune adjustments during the
(14:43):
descent phase in order to maintain the right orientation. That
also had a heat shield to absorb heat during you know,
entering the Martian atmosphere. And once it reached a certain altitude,
it deployed a parachute which helped slow its descent, and
then at a bit lower in altitude, the MSL ejected
(15:04):
a descent stage. So this was kind of a platform
with thrusters on it, and the rover was mounted inside
the platform and this would fire its thrusters, slowing its
descent further until it hovered above the Martian surface. Then
it lowered the Curiosity rover on a tether, turning the
(15:26):
descent vehicle into what they called a sky crane. The
idea was that the rover would touch down on Mars,
it would sever the tether to the descent stage, and
then the rover would be ready to go to work.
And here's the thing. This whole process from entering Mars's
atmosphere all the way to the point where the rover
touched down would take about seven minutes. But you remember
(15:50):
the delay. It was fourteen minutes of a communication delay,
So the whole process took about half the time it
takes communications to go from Mars to Earth at this
point in the two planets orbits. So the whole process
had to happen without human intervention, and not only that,
a success would mean that the rover would actually be
(16:11):
down on Mars for seven minutes before we even knew
if it had worked. And it turns out it did work,
which truly is phenomenal. And I even did a special
podcast with Tom Merritt of Daily Tech News show Fame
back when this happened in two thousand twelve. I remember
getting really emotional about this because when you consider the
(16:31):
innovation and inventiveness required to make something like this actually work,
it's really incredible. The perseverance rover will follow in curiosities
um tire tracks, and that it's going to use a
similar strategy for e d L. That stands for Intrigue,
Descent and Landing, so it's also going to use the
(16:52):
skycrane maneuver in order to land. And this time the
descent vehicle will have a couple of new tricks up
its proverbial sleeve. For example, it will have a set
of tools called Terrain relative Navigation or TRN, which will
scan the Martian terrain and allow the vehicle to change
its descent path in order to avoid any terrain that
(17:13):
looks particularly hazardous and that improves the chances of a
successful touchdown. And it's also going to have a microphone,
so we'll get to hear what it sounds like to
land on Mars. Plus if the rover wants to bust
out some David Bowie karaoke on the way down, that
microphone will come in awful handy. When we come back,
I'll talk more about the tools aboard the Perseverance, what
(17:35):
they are meant to do, and a bit about how
they work, But first let's take a quick break. Perseverance
is about the same size as its predecessor, Curiosity, which
means it's the size of a small car. It weighs
(17:56):
a bit more than Curiosity as well. UH has a
mass of one thousands, so here on Earth it weighs
two thousand, two hundred sixty pounds. If we don't include
the rover's arm. The rover measures about ten ft long
by nine ft wide, and it's seven ft tall. That's
(18:18):
a three meters by two point seven meters by two
point two meters, so it's a pretty big rover. Before
we get into the super techy stuff and the goals
of perseverance, let's look at some other related things. For example,
the launch vehicle perseverance will depend upon the launch of
an Atlas five one launch vehicle from the United Launch Alliance.
(18:44):
This is a two stage rocket essentially, and it stands
fifty eight meters or one ft tall when the payload
is attached to the top. Fully fueled. With the payload
in place, the full launch vehicle weighs five hundred thirty
one thousand kilogram ms or one point one seven million pounds.
The five for one designation tells us a lot about
(19:07):
the launch vehicle, as it turns out, so that five
and five four one refers to the diameter of the
fairing that holds the payload in place with the launch vehicle.
So in this case, the spacecraft that will hold the
perseverance and this fairing is five meters in diameter. That's
what that five means. So what's the four and five
(19:28):
or one means? Well, that tells us how many solid
fuel rocket boosters are part of this launch vehicle. So
there are four solid fuel rocket boosters, and the one
tells us how many rocket engines are in the second stage.
This is called the center and there are single engine
centaurs and dual engine centaurs, so this one is a
(19:49):
single engine centaur. The first stages rocket engine is called
the r D one eight and this one was made
in Russia. The engine burn is the fuel made of
kerosene and liquid oxygen. The second stage centaur uses fuel
made of liquid hydrogen and liquid oxygen, which must be
kept at very low temperatures to remain liquid, and for
(20:12):
that reason they are called cryogenic propellants. So at launch,
the boosters and rocket engine for the first stage will
carry the vehicle up to a certain altitude and that's
where the first stage will separate from the rest of
the vehicle. The first stage will fall back to Earth.
The second stage ignites and propels the spacecraft out to
its trajectory to bring it on an intercept course with Mars,
(20:35):
and then it separates from the launch vehicle, and then
Perseverance aboarded spacecraft will be on its way on its
very long trip out to Mars. So, assuming everything goes
as planned, Perseverance will touch down on Mars in February
twenty twenty one thanks to the skycrane maneuver. If things
don't go as planned, uh, I mean, I don't know,
(20:57):
I mean if it if it doesn't launch Biogus fifteen,
there's a real question of whether or not the project
can be put on hold for two years. And if
something goes wrong, well, I guess you know, the mission
scrapped and stuff can go wrong because space, as it
turns out, is super hard. I mean, like that thing
is trying to kill you. But let's say it all
goes to plan and the rover makes it to Mars.
(21:19):
What is it going to do when it's there. Well,
NASA says the mission will last at least one year
on Mars. That is one Martian year. That's equal to
six hundred eighty seven Earth days, so nearly two full
Earth years. If the mission is a success, we may
well see the experiments stretch on much longer than that.
(21:42):
The Opportunity mission was only intended to last for ninety days,
but it was able to continue for nearly fifteen years.
But what is Perseverance going to do when it's up
there all that time. The overall program Perseverance is part
of it is called the Mars Exploration Program or m
e P, and one of the primary goals of m
(22:04):
e P is to look for signs of life, most
likely signs that life once existed on Mars thousands and
thousands and millions of years ago. But boy, it really
would be cool if we found evidence of microbial life
on Mars today. NASA has laid out four science objectives
that Perseverance will pursue in an effort to further this goal.
(22:28):
The four objectives are looking for habitability, that is, seeking
out areas that could have supported microbial life in the
ancient past, seeking bio signatures, so looking for evidence that
microbial life actually did exist in these habitable environments, such
as in signs and the rocks themselves. Cashing samples. This
(22:50):
is all about collecting and analyzing rock and soil samples,
and preparing for humans, which will take on the super
cool challenge of producing oxygen on Mars. Now we'll dive
into these more in a moment, but in addition to
the four primary objectives, Perseverance will also study the seasons
on Mars and how weather patterns change, including stuff like
(23:13):
dust storms. It will be building on our understanding of Mars,
which will be critical if we ever do actually want
to send astronauts there or colonists. So a lot of
what Perseverance will be doing sets the stage for future
missions with actual humans on Mars. NASA is going about
this in a very methodical way. And I say that
(23:34):
because I'm sure at least some of you remember the
private organization called Mars One that had the stated goal
of establishing a permanent colony on Mars. The Mars One
Plan was to create habitats on the planet, or technically
under the surface of the planet, because Mars doesn't have
the same protective measures as Earth does when it comes
(23:57):
to deflecting harmful radiation and articles from stuff like you know,
the Sun, and the Mars One Plan didn't have anything
in it about coming back to Earth. This was a
one way trip. The organization was founded in two thousand eleven.
It attempted to raise money from investors and through an
application process in which people would vie to be considered
(24:21):
as astronauts for this mission, but it ultimately didn't go anywhere,
and that, by the way, is a big strike against
space exploration. Typically in space exploration, you gotta go somewhere, right,
So the owners ended up liquidating the organization in early
two thousand nineteen. Some people think the whole thing was
(24:41):
nothing more than a scam. Now. I don't know if
the founders intentionally set out to mislead people or not,
but I was certainly skeptical of the efforts, as it
seemed to be taking a lot of assumptions as concrete facts,
and that's dangerous. Now, that's not the case with NASA's approach.
It's always dangerous. Space is always dangerous, but they're not
(25:05):
taking assumptions as fact. Their approach is to build a
foundation of knowledge upon which future missions will continue to build,
with the hopeful goal of one day having astronauts themselves
set foot on Mars. But NASA is not quite as
cavalier as the Mars one plan. So let's start with
(25:25):
the analysis of Mars and the search for life. Then
we'll move on to the components that have more to
do with laying the groundwork for human exploration in the
distant future. And then we have the issue of ingenuity
to talk about, but that's for a kicker at the end.
One of the things Perseverance has that Curiosity doesn't have
(25:46):
is a drill. So Perseverance will be able to drill
into soil and rocks on Mars to collect samples for analysis.
The drill is on the rover's big arm, but a
smaller arm actually plays a part in the two. It
can supply sample tools to the drill, so as the
drill is working, the soil and rock that it ends
(26:08):
up removing can be collected in one of these tubes.
Then the little arm can take that tube full of
material and store it back on the rover. At the
end of this the rover will store certain rocks and
soil samples, very specific ones, ones that the team back
on Earth have identified as being particularly interesting. It'll store
(26:29):
a collection of these in a cash that's intended for
later retrieval, and the idea that these would someday be
returned to Earth. I'll talk about that at the end
of this episode. Now, this mission itself lacks the ability
to come back. There's nothing about the Perseverance mission that
allows them to return to Earth, so this will have
(26:49):
to wait for a future mission. The plan is to
collect at least twenty samples. However, the rover does have
enough equipment to collect as many as forty three. Now.
Along with the forty three sample tubes, the rover will
also carry five special tubes called witness tubes. The purpose
for these is to make sure that the stuff Perseverance
(27:11):
is finding is actually coming from Mars. See. One of
the risks of this kind of exploration is that our
equipment might unwittingly introduce stuff from Earth into Mars, and
if that stuff happens to be organic in nature, like
it happens to be the same as an organic marker,
it could mean that any evidence we find that suggests
(27:33):
life was once on Mars could actually be a total
red herring, because it could turn out that the organic
material actually came from Earth in the first place and
was unwittingly released on Mars. It's kind of like one
of those movies where you've got a crooked cop who
drops a bag of incriminating material right in front of
a suspect and says, well, why do we have here?
(27:54):
Looks like we've got some evidence, except, of course, the
rover wouldn't be doing this on purpose. It's not scuzzy,
you know, bad cop type. The witness tubes can capture
contaminants and allow researchers on Earth to discern whether the
stuff that was collected on Mars actually is totally Martian
in origin, or if it has some contaminants that were
(28:17):
accidentally brought by Perseverance, So they can do that if
those tubes ever find their way back to Earth, so
this is also part of that long term deal. The
rover will hermetically seal all the sample tubes and store
it temporarily in the rover itself, but eventually the team
will determine a location where the rover will store all
(28:39):
of these tubes called the Sample Cash Depot, and this
is where they will stay until a future mission can
pick them up and bring them back home to Earth.
There are seven major scientific instruments aboard the Perseverance, so
let's go through those. First up is the mass cam Z,
a camera mounted on a vertical gold pole, thus the
(29:01):
term mast and this is near the center of the rover.
The camera has a panoramic camera as well as a
stereoscopic imaging camera, so it can take really wide shots
of the horizon, or it can use its stereoscopic lenses
to capture three dimensional images on Mars's surface. Now, not
only will this camera be used to take lovely photos
(29:22):
and to help the team on Earth determine where to
send the rover, it also can help engineers back on
Earth learn more about the mineralogy of Mars' surface. Next,
we have the Supercam, which by day is a mild
mannered photographer for the Daily Planet. Wait, sorry, no, I
I meant that it's a camera intended to analyze the
(29:43):
chemical composition of stuff on Mars at a distance. Then
you've got pixel p I x L that actually stands
for Planetary Instrument for X ray litho chemistry. And if
you're wondering what litho chemistry is, you're not alone, because
I don't think I have ever seen that word ever
(30:03):
before I started researching this episode. In fact, as I
was researching the term, the only time I was seeing
any instance of litho chemistry as a word was in
reference to pixel itself, and this annoys me. I mean, NASA,
if you're going to use cute acronyms for your tools,
you can't just get around the inconvenience of not having
(30:25):
the correct letters by making up a word. But let's
suss it out. So litho means stone. Now it all
makes sense, right. Litho chemistry means the chemical makeup of
stones on Mars in this case, And this device uses
X rays in order to really study the stones around
(30:47):
the rover. X rays have a shorter wavelength and carry
way more energy than the visible light spectrum does. The
pixel has a spectrometer, which is a device that measures
the spectral components of something. And no, this isn't about
specters like ghosts or something. This is more about a spectrum,
(31:07):
you know, like the spectrum of electromagnetic radiation or the
spectrum of visible light. So they measure a continuous variable
of some sort, and the pixel measures the electromagnetic radiation
that's reflected off of various materials on Mars, which then
tells us more about what those materials are made of.
Then we've got these scanning habitable environments with Raymond luminescence
(31:31):
for organics and chemicals, and this is a really cute acronym.
The acronym is share Lock. This is another spectrometer, but
rather than X rays, this one uses an ultra violet laser. Now,
like X rays, ultra violet waves are shorter in wavelength
and higher in energy than the visible spectrum, but they
(31:52):
don't penetrate as far as X rays do. The spectrometer
will also measure the composition of materials on Mars and
search for the press of organic compounds. It also has
a high resolution camera for microscopic imaging, so that's pretty neat.
Then there's the Radar Imager for Mars's Subsurface Experiment or
rim FACTS. This one uses a radar system that can
(32:15):
penetrate the ground and give what NASA calls a quote
centimeter scale resolution of the geologic structure of the subsurface
end quote super nifty. Then there's one more scientific experiment
aboard the Perseverance that we need to talk about, as
well as ingenuity, something I haven't really covered yet, but
(32:37):
keep teasing, but we'll get back to that after we
take another short break. The last of the major experiments
aboard the Perseverance is the Mars Oxygen Institute Resource Utilization
Experiment or MOXI. What a rate acronym. Now, this experiment
(33:02):
will attempt to generate oxygen from the carbon dioxide that's
in Mars's atmosphere. See Here on Earth, c O two
makes up about point zero four percent of our atmosphere,
and that's it, and honestly, that's enough. C O two
is a greenhouse gas. In fact, out of all the
greenhouse gases that humans release in our atmosphere, CEO two
(33:24):
makes up eighty one point three per cent of them.
So a little c O two can go a long
way when it comes to the greenhouse effect. But Mars's
atmosphere is a totally different story. There, c O two
is a major player. It makes up of Mars's atmosphere. Oxygen,
by contrast, makes up a tiny point one three of
(33:47):
Mars's atmosphere. Here on Earth, it's twenty one of our atmosphere. Now,
it's incredibly obvious that we humans need oxygen, and it
stands to reason that would be way better if we
could produce is the oxygen we need on Mars while
you know, we're actually on Mars, as opposed to bringing
everything with us, everything we decide we need to bring
(34:09):
we have to launch off the Earth, and launching stuff
is expensive and it's risky, so it would be better
if we could create all the stuff we need while
we're already on Mars. On top of that, besides breathing,
we need oxygen as a component for rocket fuel, so
using the resources of Mars to create fuel would be
a huge deal. Again, we wouldn't have to send our
(34:31):
return trips worth of fuel out on the launch. That
would be enormous. Now, Moxie isn't going to terraform Mars.
It's a small scale experiment, more like a proof of concept.
It will take c O two from Mars's atmosphere and
convert it into oxygen and carbon monoxide through an electrochemical process.
(34:54):
So Moxie pulls in air from the environment. It will
pass that air through a filter and then pressure rize
the c O two so that it's approximately one atmosphere
in pressure. That is one Earth atmosphere in pressure, which
is much greater pressure than what you would find in Mars'
own atmosphere. The CEO two then goes to a solid
(35:14):
oxide electrolyzer or s o x E. The electrochemical process
does the separating at a temperature of eight hundred degrees celsius,
so things get pretty toasty. There are gas preheating components.
There's also an exhaust cooling component. All of this is
really important for moxy to operate, but also it's important
(35:35):
to cool the exhaust in order to protect the other
experiments that are aboard the Perseverance. The exhaust also has
to pass through a filter before it can be vented
back out to the Martian atmosphere. Now why is that, Well,
it gets back to those contaminants I mentioned earlier. We
have a responsibility to limit the sort of contaminants we
could introduce to another planet, and there's actually an official
(35:58):
policy about this is called the Planet Erry Protection Requirements. Now,
assuming Moxi's experiments are successful, we might see NASA and
other organizations create larger implementations of this same technology to
make a significant amount of oxygen from the Martian atmosphere.
And that will be a big step in the direction
to send people to Mars, as it will give those
(36:19):
people an important component for making the rocket fuel needed
to return back here to Earth. And now finally it's
time to talk about ingenuity, a high risk, high reward
experiment it's high risk because no one really knows yet
if it's actually gonna work. It's high reward because if
it does well, we'll have an incredible experience that we
(36:40):
can build upon. So what the heck is Ingenuity? It's
a helicopter. Yeah, Perseverance is bringing along with it a
helicopter to Mars, so you can get to the chopper
and get to Mars at the same time, thus fulfilling
two different Arnold schwarz Senegger film plots simultaneously. It's never
(37:04):
been done before. Now let's get more specific. When I
say helicopter, I don't mean the sort of flying vehicle
that carries people around here on Earth. This is more
like a drone. It's a very small aircraft. It's autonomous,
which yeah, I would have to be. There's no way
you can fly this thing via remote control back here
(37:25):
on Earth. It would crash and then you'll be waiting
fifteen minutes or whatever in order to find out about it.
The Ingenuity has a mass of one point eight kgrams,
so here on Earth it weighs four pounds, and it
makes sense that it needs to be lightweight because the
Martian atmosphere is so thin. Now, Remember, heavier than air,
(37:46):
aircraft need to generate lift, and you can think of
lift as a force that presses up on the underside
of a wing or, in the case of a helicopter,
the underside of its rotors, which really a rotor is
just a wing that moves in a circle. This force
has to be strong enough to counteract the weight of
the object in order to get off the ground. If
(38:09):
the gravity of Mars were the same as that of Earth,
this would be super hard to do because the atmosphere
is so thin you would struggle to generate enough lift
to counteract the weight of the flight vehicle. But gravity
on Mars is also not as strong as it is
here on Earth. It's actually about one third of Earth's
gravity a little more than that. So yeah, you've got
(38:32):
a thin atmosphere, but you also have less gravity and
therefore less weight to worry about. So your mass stays
the same because gravity does not affect how much mass
something has, but your weight is different. So while the
helicopter gadget weighs around four pounds here on Earth, on Mars,
it's going to be closer to a pound and a half.
Now I would still have one pot eight krams of
(38:54):
mass because mass doesn't change, but that mass would weigh
the same as an object that has just point six
eight kilograms of mass here on Earth. So if somehow
you were able to take an earth point six eight
kilograms and put it against this thing while it's on Mars,
the scales would balance out. Now, considering the rotors on
(39:17):
this thing, I'm actually really impressed they were able to
get the weight that low because each rotor, and there
are two of them, measures four feet or one point
two meters in lengths Now, just remember that these rotors
are mounted in the center. So the helicopter also has
solar panels. Those are going to be used to charge
the onboard battery. It has a wireless communication system that
(39:40):
allows engineers on Earth to relay commands to the helicopter
via the rover. So in this case, the engineers could
give pretty general commands, such as how long the helicopter
would operate or how high it was to fly. But
then the helicopter has to do all the actual flying
on its own. There will be no steering this thing
due to that community cation lag. The helicopter has inertial sensors,
(40:04):
so it can tell what it's orientation is whether it's
upright or not. It's also got a laser altimeter, so
this is essentially a laser range finder, so it shoots
a laser at the ground. It essentially measures the amount
of time it takes for the laser to go out
from the laser range finder, hit the ground, and come
(40:24):
back up and hit a sensor, and from that it
can determine how high up it is. It's also got
two cameras on board. One of them can take color
images and the other one can only take black and
white images. And it's got some heating components inside of it,
which is important because it needs to stay in an
operational temperature even during the Martian night. Uh the average
(40:45):
temperature on Mars is about minus sixty degrees celsius, though
in the daytime during the Martian summer, if you happen
to be near the equator, you might reach a high
of up to twenty degrees celsius. That's twenty degrees positive.
So there is a really wide variation in temperatures on
the planet. That's something else that we would have to
(41:07):
prepare for if we were to ever actually, you know,
go there. Now, NASA has made it clear that this
aircraft is considered a quote completely independent of the Mars
twenty twenty science mission end quote, which is why the
ingenuity doesn't really show up when you look at the
breakdown of experiments that are aboard the Perseverance. It's also
described as a quote demonstration of technology end quote. That
(41:31):
means ingenuity isn't going to be relied upon to deliver
any you know, scientific data about Mars. It's really meant
to give us an idea if the powered flying device
is a viable approach on Mars. It's also meant to
prove that the manchaization of technology is necessary to allow
for this will actually work. And if it does work,
(41:51):
then that means we could see all sorts of flying
drones deployed to Mars in the future to do stuff
like map out areas or survey regions that are to
treacherous for rovers to manage, or perform other scientific experiments. Now,
my hope is that all of these experiments teach us
a lot more about our neighbor planet, and that with
this information we can plot out further missions. And I
(42:14):
think it would be truly remarkable if I were to
see people land on Mars within my lifetime, and as always,
there are opportunities for the things we learned in the
technology we developed to make all this possible to benefit
us in other ways. One of the coolest things about
space exploration that's not really about the exploration itself, is
(42:37):
that all the technology that was once created as a
necessity in order to achieve mission goals has kind of
found its way into our daily lives and other implementations.
We often see unanticipated benefits as byproducts, and so I
think it's always a good thing for us to push
back our boundaries of ignorance. You never know what sort
of things you're gonna uncover along the way. As for
(42:57):
future missions, there are a couple more that I can
mention briefly. One is a part of a mission that
is called the Exo Mars Program. This one is actually
led by the European Space Agency and the ros Cosmos
State Corporation. The plan is to launch a rover which
would not be that much different from Curiosity and Perseverance
(43:19):
in twenty twenty two, again two years apart. This one
will be called the Rosalind Franklin, named after the British chemist.
NASA is contributing some of the UH components that are
going to be used in some of the scientific instruments
as part of this rover. The rover's mission is very
similar to that of Perseverance, primarily looking for evidence that
(43:41):
life could have existed on Mars in the ancient past.
Another mission is the aforementioned plan to retrieve the samples
that Perseverance is going to collect, assuming its mission is successful.
This one is a more long term plan because of
the complexities of getting two and back from Mars. So
(44:03):
going from Earth to Mars and back again, really we've
only managed one way trip so far, this would be
a lot harder. The current proposed timeline would have a
launch of the initial vehicle, the Sample Return Lander, in
July twenty six, which would actually touch down on Martian
soil in August twenty eight. Now that's an unusually long
(44:26):
travel time and honestly I don't know all the reasons
for that. But the lander will have its own mini
rover provided by the European Space Agency, and this rover
will go and fetch the stored samples that Perseverance had gathered.
In one it will bring those samples to a rocket
that is carried aboard the Sample Return Lander, and the
(44:48):
rocket will blast off, the first time in history that
we will have launched a rocket from another planet, and
it will then send the payload to rendezvous with another
spacecraft in orbit around Mars. That spacecraft is called the
Earth Return Orbiter, and it will actually launch from Earth
separately from the lander. It would launch in September, a
(45:10):
couple of months after the lander has launched, but it
will arrive in orbit around Mars by October, several months
before the lander touches down. The Sample Return container from
the rocket will separate, it will dock with the Earth
Return Orbiter, and then the orbiter would prepare for the
trip back home once Earth and Mars were lined up again,
(45:34):
and the estimated return date would be sometime in twenty
thirty one. So if everything goes well, it's going to
take more than a decade to get those Martian rocks
and soil back here on Earth for analysis. Man, this
stuff is hard, but super interesting, and that wraps up
this episode about perseverance. It remains to be seen if
(45:57):
the launch is going to be a success. I certainly
hope it is. I plan on watching it on July,
assuming that the launch goes ahead as planned, and I'm
wishing everyone all the best. This is a very exciting
kind of mission, and as I said before, I find
it personally very inspiring that we can achieve something that
(46:18):
is so difficult to do, and if we can do that,
then we can tackle some of these problems that are
enormous here on Earth that seem impossible. But it may
just be that we're not dedicating the effort and the
resources necessary to really change things. And I think that
that is something we could entirely do if we set
(46:38):
our minds to it. If you guys have future suggestions
for tech Stuff episodes, or rather suggestions for future tech
Stuff episodes, either way, the only way I know about
it is if you send them to me, So send
them to me on Twitter. To handle for the show
is text Stuff H s W and I'll talk to
you again really soon Y. Text Stuff is an I
(47:05):
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