InSight into Mars

On November 26, 2018, NASA engineers and scientists celebrated upon receiving confirmation that the Martian lander InSight had touched down successfully. What does InSight do and what will it tell us about the Red Planet?

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Episode Transcript

Speaker 1 (00:04):
Get in touch with technology with tech Stuff from how
stuff works dot com. Hey there, and welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
House to Parks and I heart radio and I love
all things tech. And On November two, eighteen, after traveling

(00:24):
four hundred fifty eight million kilometers or three hundred million
miles on a trip that lasted nearly seven months, the
robot platform Insight touched down on the surface of Mars.
They marked the eighth time the United States has managed
to land a mission on Mars successfully. So we're gonna
take a look at this lander, what it does, and

(00:46):
what it's mission parameters are. Before I get into Insights specifically,
it's a good time to chat about the logistics of
just getting to Mars in general. You may have heard
that if we were to send people to Mars, they
need to stay there for about two years before they
could return. So why is that, Well, it's because of
the respective orbits of Earth and Mars. Mars is further

(01:09):
out from the Sun than the Earth is, and a
Martian year lasts six hundred eighty seven Earth days or
six hundred sixty nine souls or Martian days compared to
an Earth year, which has of course three hundred sixty
five days, unless it's a leap year. So there are
times when Earth and Mars are relatively close, and by
relatively I mean nearly thirty five million miles or fifty

(01:33):
six million kilometers apart, and there are other times when
they are opposite each other with the Sun in the center,
they're bout as far apart as they possibly can be.
Space travel is expensive and it requires a lot of fuel.
Fuel ways a lot, and the heavier year spacecraft gets,
the more fuel you need, so you end up in
this sort of cycle up to a point where you

(01:55):
have to keep adding fuel to lift not just the
spacecraft but the fuel you are already have in it.
So that means you get to be super careful with
how heavy your spacecraft is so that you can be
very efficient with the amount of fuel you're going to
need to get to your destination. So that includes playing
your trips so that you travel the shortest possible distance

(02:17):
between two points, taking the least amount of time to
get from point A to point B. So you want
to set a launch date in advance of a time
when Earth and Mars are going to be relatively close
to each other. That's the launch window we want to
look at. But of course Mars is moving the whole
time as his Earth. So really you're setting a launch
window to aim at the point in space where Mars

(02:39):
is going to be in several months after the launch.
It's actually pretty complicated stuff. I mean, they do call
it rocket science. Even when you take advantage of orbital paths,
you're still talking about a trip that will take between
six and eight months using conventional rockets, So you have
to settle in for a long trip. Now, once you
get to Mars, you won't be able to leave right

(03:01):
away if you have a method of leaving in the
first place, you would have to wait around for Earth
and Mars to be nearing one another again. And a
launch window for the minimal amount of energy needed to
get between the two comes around only every two Earth
years and two Earth months, So you need enough fuel
to make the trip home, or you need some way
to make the fuel at your destination, such as Mars,

(03:24):
so that you can make the return trip. Now, you
could make going to Mars a one way trip, and
considering how hostile the planet is and how hard it
would be to get back. That's probably not entirely unrealistic,
if I'm being honest. We'll talk more about that in
our next episode, but before we decide to shove someone
off into space for a life sentence on Mars, we

(03:48):
can send other craft to the red planet, and in
fact we have that includes orbiters, which, as the name suggests,
orbits the planet and gathers information about it. Landers, which
has the name suggests, lands on the planet and gathers
information about it. And rovers, which, again the name tells

(04:09):
you everything you need to know. It roves about on
the planet, gathering information and you know, doing sick donuts,
and the name is pretty much tell you everything you
need to know about them, at least in a general sense.
So landing on Mars, particularly if you want to do
a soft landing, is pretty challenging as well. That's because
of several factors. One is that the Martian atmosphere is

(04:32):
much thinner than Earth's, so stuff like parachutes are less effective.
They do work, but they don't slow down to scent
quite as effectively as they would if you were using
them on Earth. However, the atmosphere is thick enough to
cause heating problems. Upon entry of the atmosphere, the spacecraft

(04:52):
starts to come in at a very high speed, it
hits the atmosphere, starts to compress the atmosphere in front
of it, and it begins to heat up rapidly. So
whatever your spacecraft is, you need some really good heat
shielding to take care of that problem. That of course
adds to the weight of the spacecraft. And while gravity
on Mars is less intense than on Earth, the gravity

(05:14):
on Mars is about point three eight times out of
Earth's gravity. Descending from Martian orbit still means you're going
at a speed that's plenty fast enough to cause serious
damage when you hit the ground, So you have to
have a way to slow your descent. One way to
offset that incredibly fast descent is to have special retro
rockets on the landing craft and to fire those before

(05:37):
you land so that you have a nice and gentle touchdown.
That really would help slow the descent. But here's the
thing with these craft that we're sending the landers and
the rovers. For the ones that we're using for a
soft landing, they have to rely upon a fully automated system.
Because the distance between Mars and Earth is such that

(05:58):
it takes several minutes for radio signals to pass back
and forth between the two. Radio signals move at the
speed of light, but the distances involved are so great
that even light requires a few minutes to get the
job done. So if you were looking at a video
feed from the spacecraft, let's say that there's a live
camera feed and it's able to send video back to Earth.

(06:20):
This would be unrealistic, But let's say it's happening. What
you would actually be looking at would be video from
several minutes ago. The video footage would be several minutes old,
because that's how long it took for the information to
travel from the the lander or rover on Mars to
get to you on Earth. Sending a message to the

(06:40):
lander would obviously take more time. So let's say you
see a picture and you think, oh, well, that's that
rock over there is interesting. I want this thing to
go grab that rock, and you send a command to
the device. Well, keep in mind the picture you're looking
at it several minutes old. When you send the message,
it takes several more minutes for it to get back.
The device then has to react to it, and it

(07:02):
will take even more minutes for you to know that
anything actually happened, so there's no way to make any
adjustments in real time at all. So that's why the
system has to be fully automated. When it's landing, there's
no way to step in and take control of it
as a remote pilot, because the distances are so great

(07:26):
that by the time you're sending commands, the thing you're
trying to command has already crashed into Mars. So you
have to create this automated system. The landing process for
this lander would take about six and a half minutes
from the point it enters the Martian atmosphere to the
point that it landed on the surface. NASA would call

(07:46):
this the seven minutes of Terror. That six and a
half minutes would include every single thing that would have
to happen in this process of entering the atmosphere all
the way to the point of firing the retro gets
at settling down on the surface of Mars. If anything
were to go wrong at any stage there, whether it

(08:07):
maybe it's a parachute that fails to deploy, a thruster
that fires a second too late, whatever it would be,
all would be lost. Chances are you would have a
total loss of the spacecraft. In addition, that distance between
Earth and Mars would mean we wouldn't even know that
something had gone wrong until about eight minutes after it
had gone wrong, So if the lander were to crash

(08:30):
and be destroyed, it would have been destroyed for eight
minutes before we knew about it. Also, it meant that
picking a landing site is incredibly important. You want to
find the best possible site to target so that your
lander or rover, whatever it may be, has the best
possible chance of survival. NASA had to find a spot

(08:52):
that not only would be optimal for whatever the mission
objectives happened to be. In this case, it's all about
measuring various uh features of Mars, but it also has
to be geographically favorable for that successful landing and for
a continued operation. Sou with the case of the Insight,

(09:12):
it also meant that having to pick a spot that
would be favorable for solar panels, because that's how the
the Insight lander recharges its batteries. So for that reason,
they chose a spot near the equator because that would
maximize solar exposure, and because you're relying upon automated systems
to guide the landing craft to the surface. You also

(09:33):
have to pick a location that's relatively flat and free
of large rocks or boulders that could cause the craft
to topple over after touchdown. That is a tough thing
to look for on Mars. Mars is very very rocky
and uneven in many places, but the team in NASA
eventually chose a region of Mars called the Elysium Planetia.

(09:53):
That was way back in when they made that choice.
That first, NASA had more than twenty potential landing sites
identify light. Then the team directed the Mars Reconnaissance orbiter
to gather images of those sites so that they could
choose the best candidates. Each potential site measured eighty one
miles by seventeen miles in an elliptical shape. That's a
hundred thirty kilometers by twenty seven kilometers. The insight landing

(10:17):
location is about three d seventy miles or six hundred
kilometers away from where the curiosity rover is, so it's
probably not going to get a visit from its fellow
robot anytime soon, and a monitor the progress of the
actual landing. NASA sent up a pair of small satellites
called cube SATs. Along with the Insight These were the

(10:38):
first two cubes AT spacecraft to journey into deep space.
They are communications relay satellites. These particular cube SAT satellites
are the Jet Propulsion Laboratory designed and built them. The
basic unit of a cube sat is a box about
ten centimeters or four inches to a side, and CubeSats
can be made up of multiple units, and the two

(10:59):
that were hitching a ride with Insight were each six
units large. The job of those two satellites involved flying
by Mars and listening for Insights signal that would indicate
a successful landing. The CubeSats both have UHF capabilities, though
they can only receive UHF radio signals and X band capabilities,

(11:19):
which meant they could receive and transmit over those frequencies. Interestingly,
those satellites separated from the launch vehicle that was an
Atlas five rocket, and they did so independently of the
Insight cruise spacecraft, and so they flew to Mars on
their own trajectories and with their own course adjustments in

(11:39):
order to get to where they needed to be for
the actual landing procedure. The satellites also served as a
pilot program to test the viability of a bring your
own communications relay with a short development cycle into deep space,
and it worked. Now I have a lot more to
say about INSIGHT and what it does, but before we
get to that, take a quick break to thank our sponsor.

(12:09):
The full name for INSIGHT is the Interior Exploration using
Seismic Investigations, GEO Daisy and Heat Transport. And I have
a sneaking suspicion. This is another case of a mission
getting a fun name and then a project team tries
to work backward to make that name into an acronym.
But I don't know that for sure. The purpose of

(12:31):
the mission is to deduce how celestial bodies that have
a rocky surface are formed, how do they come to be.
This would include planets like Earth, as well as satellites
like our Moon, and of course planets like Mars. The
Lander is going to do this by using several scientific
instruments to study the deep interior of Mars, and then

(12:54):
the team back on Earth is going to take the
information and form hypotheses to explain the formation process. The
Lander will also gather data that will allow scientists on
Earth to make educated guesses about Mars's core. So this
is really cool. This is all about observing planet's behavior
in a way and then drawing conclusions about what that

(13:17):
means for the planet, what how the planet is made up,
you know, what sort of core it has, that kind
of stuff, and it's all about working backward based upon
these observations. I love this kind of science. Insight is
kind of like the Phoenix Lander, and that both of
those are stationary robotic platforms, so it's not like the Spirit,

(13:40):
Opportunity or Curiosity rovers. Those are all robots with wheels
that can move around the surface of Mars. Actually, the
Opportunity and Curiosity rovers are still in operation to this day.
Opportunity landed on Mars in two thousand four and Curiosity
landed in two thousand twelve, and there's still kind of
roaming around. But insights job is to monitor conditions from

(14:01):
a set location over the course of a Martian year
plus forty or so martian days. Insight is a pretty
large lander. NASA describes it as being about the size
of a big nineteen sixties convertible. That's a quote, but
this is tech stuffs. Let's get technical. What are the

(14:22):
specs for the Insight Lander, well, it is six ms long.
That's about nineteen ft eight inches, assuming you're measuring it
when it's solar panels are deployed. Again, we'll talk about
the solar planel panels in just a minute. It's got
a width of one point five six ms that's about
five ft one inch. Uh. The deck height, so the

(14:43):
the top surface of the main portion of the lander
ranges from eighty three centimeters to one centimeters tall or
thirty three to forty three inches. The whole thing weighs
in at a smelt three d sixty ms. Technically that's
its mass. Uh we If we're expressing it in pounds,
it would be seven pounds here on Earth. Remember, on

(15:05):
Mars the mass is the same, but it weighs less
because again, mars Is gravity is a little more than
one third that of Earth's gravity. The lander has a
lot of cool gadgets attached to it. It draws power
through batteries that are recharged by those solar panels I
had mentioned. Those actually had to deploy after Insight touched down,

(15:27):
before they were all folded up and tucked away on
the sides of the platform for safety. About an hour
after touchdown, they began the deployment phase and this involves
unfolding and then they can start catching the sun's rays.
And there's a great website for the lander over at
NASA's Jet Propulsion Laboratory that shows animations of the solar

(15:50):
panels deploying as well as the other tools and how
those get deployed. The animations are fantastic, they really help
a lot, So I highly recommend if you're interested in
the Insight Lander checking out the interactive web page over
at the Jet Propulsion Laboratory because it's it's fantastic and
it looks super cool. Uh. The panels, the solar panels

(16:12):
are decagonal. That means they have ten straight sides and angles.
You know, an octagon is eight sides and eight angles.
A decagon is ten, so they're kind of circular in shape,
but they have those flat edges. The panels measure about
seven feet or two meters across, and there are two
of them. Has a pair of these solar panels. According

(16:34):
to one NASA web page, the combined surface area of
the two solar panels is quote as large as a
ping pong table end quote. So you know, some light
recreation on Mars. If you if you decide that it's
served its purpose, I guess they're able to generate about
three thousand what hours of electricity every martian day. Another

(16:55):
important component on this lander is its robot arm. The
arm has three degrees of freedom and those roughly translate
to a human shoulder, elbow, and wrist joint. The arm
has four motors to control the movements of the arm
and those joints. And at the end of the arm,
instead of there being a hand or like a claw,

(17:17):
there's actually a grapple. It's attached by a cable. It
dangles at the end of the arm, and this is
used to grasp the various tools on the platform deck
in order to lift them up and deploy them onto Mars' surface.
So it kind of looks like one of those claw
games you see in arcades or in the Toy Story film.

(17:39):
It kind of looks like that, except that the claw
does not descend and ascend. The cable doesn't unwind and wind.
It stays the same length, so the arm itself will
tilt up or down. But the claw does dangle from
a cable. It just the cable itself is stationary. It's
also got a firm grip, which also means it's not

(18:00):
really like a claw game because those things are rigged
I tell you, stupid Teddy Bear. Anyway, it's a super
cool way of manipulating objects on the lander, and again
the animations are really fun to watch. There's a camera
mounted on this arm it's actually between the elbow and

(18:21):
wrist joints that can provide NASA images of Mars and
help the team make sure that the instrumentation that's attached
to the platform is properly deployed. In fact, it's called
the Instrument Deployment Camera or i d C. So the
main purpose for the arm is to place the two
of the three main sensors on the platform, two of
the three main scientific experiments really on the surface of Mars.

(18:46):
More on those two experiments in just a moment. The
lander actually has a second camera. That one is mounted
just below the surface of the deck. This one is
called the Instrument Context Camera or i C SEE, and
it has a fish eye perspective with a field of
view of about hundred twenty degrees. It's aimed at the

(19:06):
ground near the lander that serves as the landers work space.
So both cameras have a resolution of one thousand, twenty
four by one pixels, which is not quite a two
megapixel image. And in an interesting analogy, NASA has compared
the mission to a human getting a medical check up.

(19:27):
The Insight Lander is going to check Mars's vitals, which
includes the planet's pulse, temperature, and reflexes. So what was
that all about. Well, these are all kind of cute
ways to talk about the main instruments and scientific projects
connected to the Insight Lander. So let's start with the pulse,
the pulse of the planet in this case. In this context,

(19:50):
it refers to the seismological events on Mars. So things
that make the earth shake, or I guess I should
say Mars shake, it's not the earth there so, or
as my former co host Crispalett would say, stuff what
makes the ground shake. One of the instruments inside has
is a special seismometer with a super cool wind and

(20:12):
thermal shield. The seismometer has a cable tether that connects
it back to the Insight Lander, and the cable's purpose
is twofold. It contains both the power line and the
data line for the seismometer. So this is the way
that the lander can provide electricity to the seismometer, and
the seismometer can feed data back to the lander. The

(20:34):
illustrations I've looked at make it a little like the
insight lander is kind of walking a weird, lumpy robot dog.
The lander's robotic arm is responsible for lifting the seismometer
off the platform and placing it on the surface of
Mars near the lander itself. Then it has to put
the uh the thermal and wind shield over the seismometer.

(20:56):
The purpose of the shield is pretty much what sounds like.
It's meant to protect the seismometer from gusts of wind,
primarily that would possibly cause the seizemometer to register false readings.
If the wind pushes the seismometer around that it's going
to start registering as if there's an earthquake or Mars quake.
I guess this way, the shield blocks that wind and

(21:16):
the seizemometer just keeps on, you know, monitoring the movement
of the ground beneath it. The wind and thermal shield
is made out of aluminum. The main shielding part on
the top anyway, is made out of aluminum. It looks
like a dome with little lander legs almost like a
little ufo. It also has a metallic skirt that hangs

(21:36):
down beneath the dome. It's the thermal skirt. It's actually
made out of gold. And then this gold skirt has
a bottom edge made out of and I am not
making this up, honest to goodness, the edge is made
out of chain mail, like the stuff that nights used
to wear back in medieval times. How cool is that?

(21:59):
So this chain mail actually serves a couple of different purposes.
For one, it's it's heavier than the skirt is, so
it helps pull down on the skirt while the little
arm is lifting the shield up off the deck of
the lander. The chain mail provides the weight to help
pull the skirt straight so that it goes down all
around the sides of the seismometer. Also, the chain mail

(22:23):
is flexible, so it can drape over any small pebbles
or rocks to allow a pretty good seal of the
shield over the seismometer. The shield itself is about fourteen
inches or thirty five centimeters tall, twenty seven inches or
sixty nine centimeters in diameter, and has a mass of
twelve kilograms, which means here on Earth it would weigh
about twenty six and a half pounds. I'll finish up

(22:46):
this section by giving a quick overview of how seismometers work,
and then we'll talk about the other two experiments in
the next section. So typically we would pair a seismometer
up with some sort of recording device, which would mean
that we would have a seismograph. That's when you have
the two components together. So a simple version of this
one that you might see here on Earth uh, an

(23:08):
old school simple mechanical version of a seismometer would be
a frame that has good contact with the ground. So
you've got a frame that is set on whatever surface
you're measuring. Suspended from the top of that frame would
be a weight on a spring, and the weight would

(23:29):
hold some sort of writing utensil, like a pen. That
pen the end of it would rest against a strip
of paper that could be rolled or pulled in such
a way that the pen is drawing a line on
that strip strip of paper as the paper moves past it.
If there's a trimmer, the frame is going to move
along with the ground, but the suspended weight will tend

(23:53):
to remain motionless as it is largely isolated from the
ground and the frame and an object at rest tends
to stay at rest. So you can think of it
as the frame and the earth and everything else is
moving up and down. The weight is kind of just
staying where it was, and that means that the paper
is going to be moving up and down against the pen.

(24:14):
Not the pen against the paper. The paper itself is
moving up and down because the ground is moving up
and down. And that means that the pen is gonna
start drawing squiggles on this paper. And so you could
look over the paper and wherever you saw squiggles, you'd say,
all right, well that was where there was an earthquake
or an aftershock, or maybe a large truck drove by
or whatever. The seismometer on the insite works on a

(24:35):
similar principle, except instead of holding a pen, instead of
it being mechanical, the relative motion between the weight and
the frame would create an electrical voltage, and changes in
that voltage are recorded by a computer system on the
insite and transmitted back to Earth, and those are interpreted
as the various quakes. I have a lot more to
say about the experiments aboard the Insight, but first let's

(24:58):
take another quick break to thank our sponsor. So the
second vital sign Insight is going to monitor is temperature.
The deck of the lander has a temperature censor of
its own to give surface readings. But what I think

(25:19):
is super interesting is what is called the HP three instrument.
HP three stands for heat flow and Physical Properties probe.
It's another tethered instrument that connects back to the lander,
and like the seismometer, the robotic arm has to lift
up the HP three and then place it on the

(25:39):
surface of Mars in the work space in front of
the lander. Inside this instrument is a probe. It looks
like almost like a spike, and it's called the mole
and it's tied. It's a type of pine traumater. I
didn't even know that was a word until I did
this research, but that essentially is a tool designed to

(25:59):
pay to trate a surface. That's the name pentatrometer. In
this case, we're talking about the Martian soil. So inside
this spike, which again is is got a cable out
the back of it that goes back up into the instrument.
The cable is held in a way where it can
be fed out gradually, so that as the spike is
digging down it can continue to have enough slack to

(26:22):
do this. But inside the spike, inside the penta traumeter
is a weight on a spring. Essentially, that's a hammer.
It's inside the spike. So imagine you've got a nail
or a railroad spike or something like that. But the
hammer for this nail or spike is actually inside the
spike or the nail itself, so it's a self hammering nail.

(26:47):
The mechanism draws power from the lander to pull back
the weight that compresses a spring, and then you latch
it into place. When it's completely compressed, you can unleash
this weight. The spring will expand rapidly, pushing the weight
down so that it collides with a little section at

(27:07):
the very tip of this probe, and it's like a
hammer knocking a nail, and it starts to hammer the
spike down. This is actually a pretty slow process. It
does not happen super fast. It's not like one, uh
one bash and suddenly the spike is several feet in
the soil. That's not the way it works. It's very gradual.

(27:29):
So by keeping a careful tension on the cable so
that the spike is properly positioned, and by doing this
several times, you start to drive the spike down into
the soil. It's gonna take months, but ultimately this mole
is going to dig down to a depth of about
five meters or sixteen feet, which is deeper than anyone

(27:51):
has dug on Mars up to this point as far
as we know anyway. But obviously this instrument is doing
more than just digging a hole on Mars. I mean,
that's super cool the way they're doing it, but that's
not the only thing it's doing. The probe and the
tether that's trailing behind it contains temperature sensors, and those
sensors will monitor the heat flowing from the interior of Mars,

(28:14):
which will help tell scientists what the inside of Mars
is like. It could inform scientists about how active Mars
is and whether it's made out of similar stuff as Earth.
The probe isn't just listening either. As the probe digs
down at certain stages, it will occasionally stop and it
will put out a pulse of heat of its own.

(28:36):
Then it will monitor how that heat flows through the
material around the probe. So if that material happens to
be a good conductor like metal, like coppers. A great
conductor of heat, the heat will decay very quickly, it'll
move outwards through this conductive material. But if it's a
poor conductor, more like glass, the heat's going to stick

(28:58):
around a lot longer. The HP three probe weighs in
at about six point five pounds at least it would
here on Earth. That means it has a mass of
about three kims and it only consumes to watts max
as the probe starts to dig down into the Martian soil.
The last of the three big experiments would be a

(29:19):
pair of RISE antennas on the deck of the lander.
These would not be removed from the deck and placed
on the Martian soil. They will stay on the lander.
RISE stands for Rotation and Interior Structure Experiment. These antennae
will track Mars's motions as it rotates, so essentially, it's

(29:40):
all about detecting that wobble. So how much does Mars
wobble around? Knowing how much it wobbles around will tell
scientists valuable information about Mars's core. How big is Mars's core,
Is it a solid core, is it a liquid core?
What elements besides iron might be in the core. Well,
the way Rise works is actually pretty darn simple. It

(30:03):
listens for an incoming signal from Earth, and then it
sends the signal back to Earth. This will reveal the
precise location of the lander, well precise location from a
few minutes in the past. Because again the signals can
only travel as fast as light, it may take a
few minutes for that to happen, depending upon where Earth
and Mars are in their respective orbits. But back on Earth,

(30:26):
computers will take this this return signal and analyze it
for changes and looking for evidence of Doppler shift. I've
talked about Doppler shift many times on this show, but
just so you remember, if you've got something moving in
a wave, whether it's a radio wave or a physical wave,

(30:50):
whatever it may be, h it has a certain frequency.
And if the wave is coming from a stationary object
and then it hits a different state stionary object, any
reflective waves. Reflective waves that come back to the source
are going to be unchanged except for their direction. Right
that you're gonna get back the same frequency of wave

(31:12):
if both objects are stationary, But if the objects are
moving closer to each other, the returning wave is going
to be compressed, so it's going to be at a
higher frequency. If the two objects are moving away from
each other, the wave is going to be elongated to
a lower frequency. And by measuring these changes, scientists will
be able to figure out how much Mars is wobbling

(31:34):
around as it orbits the Sun. Now, Earth wobbles every
eighteen years thanks to the Moon's pull on us, and
we already know that Mars does in fact wobble, In fact,
it wobbles over the course of a single Martian year,
but we don't know to what degree how much does
it wobble. We know it does, we just don't know

(31:55):
how uh intense that wobble is. So the Rye his
instruments will provide more information to fill in this knowledge gap.
And the amount of wobble planet has depends partly on
what is in the delicious neugute center of that planet. So,
as NASA points out in a really helpful web page,
a hard boiled egg is going to spend faster than

(32:17):
a raw egg. Also, planets that have liquid cores will
wobble more when they spend. Planets with a solid core
will wobble less, and this in turn can help us
make other hypotheses about why Mars has a very weak
magnetic field in comparison to Earth's magnetic field. So it's
all about learning more about why is Mars the way

(32:38):
it is and more about how Mars actually is. There
are other instruments on the lander that aren't getting quite
the same level of coverage. The lander has an atmospheric
pressure sensor, for example. It also has a uh F
antenna to allow the lander to communicate to satellites that
are in Martian orbit, which includes the Mars Reconnaissance Orbiter

(33:00):
and the Mars Odyssey Orbiter, both of which pass over
in Sight two times every Martian day. And there are
other satellites that can chat with as well, like the
European Space Agencies Trace Gas Orbiter or NASA's Mars Atmosphere
and Volatile Evolution Orbiter also known as MAVEN. It can
talk to those in a pinch if it needs to.

(33:20):
So Insight will stand on Mars doing its thing for
at least a Martian year plus some change, maybe longer
things continue to work out properly. Sometimes these missions can
go well beyond their initial projected phase, and if NASA
can figure out other things to do with the material
that's already there, then that is incredibly helpful. There's some

(33:43):
other elements on it as well. There's a reflective surface,
for example. They could be used to locate the precise
position of the lander. You just direct a laser at
it and look for the reflection. I'm sure we'll learn
tons of interesting things about Mars using this device, and
probably a lot about Earth as well, which pretty exciting stuff. Now,
in our next episode, I'm gonna stick with Mars for

(34:04):
a little bit. I'm gonna talk about the various proposals
to send people to Mars and what that would entail,
and we'll talk about why it would be super hard
to do and why some people like Bill and the
Science Guy are skeptical that we're ever going to actually
go there for a prolonged stay. And maybe we'll also
talk about why Elon Musk thinks there's a decent chance

(34:25):
he's gonna end up there. So tune in tomorrow to
hear that episode. If you guys have any suggestions for
future episodes of tech Stuff, whether it's a specific technology,
that type of of gadget that you've always wanted to
know more about. Maybe it's a company history that you
want to know more, or a person in tech let
me know. Send me an email. The addresses tech stuff

(34:46):
at how stuff works dot com. Don't forget to go
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(35:07):
see something you really like. And that's all for me.
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