July 3, 2019 • 43 mins
In June, 2019, the OSIRIS-REx satellite entered an orbit less than 2,500 feet above the asteroid Bennu. In a few years, we might be mining asteroids. How will we do it, and why?
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Episode Transcript
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Speaker 1 (00:04):
Welcome to tech Stuff, a production of I Heart Radios,
How Stuff Works. Hey there, and welcome to tech Stuff.
I'm your host Jonathan Strickland. I'm an executive producer with
how Stuff Rex and I Heart Radio and I love
all things tech. And On June twelve, two thousand nineteen,
a small spacecraft called Osiris Rex set a new out
(00:29):
of this world record. That record was for entering the
closest orbit around a small planetary body, and the record
was previously held by well Osirius Rex, but now it
was really extra super close, like six d eight meters
or less than unred feet close. The planetary body is
(00:55):
the asteroid Bnu b e nn you. It will eventually
get even closer to Benu. The plan is for the
spacecraft to make contact with the asteroid for the purposes
of collecting a sample, then it will begin its journey
back to Earth. Right now, it's taking a series of
images of the asteroid, partly so that a team back
(01:16):
here on Earth can evaluate the best spot to make
that point of contact. It turns out Benu is a
bit more bumpy than we anticipated, so finding a spot
that will be suitable for a Cyrus Rex and given
the best chance for a successful mission is no small
task in of itself. That's the short version of the story.
(01:37):
But today I want to talk more about the mission,
the technology, and the long term plan to mine asteroids
as part of the overall strategy for deep space operations.
And this isn't the first time I've talked about asteroid mining.
Way back in June two thousand twelve, my co host
Chris Palette and I talked about this idea, and we
(01:58):
also replayed that episode in May two thousand nineteen. So
some of this might sound a bit familiar since I'll
be tackling a similar subject, but it's well overdue for
a follow up, So let's begin with a high level
view of what asteroid mining is all about. There are
many different types of asteroids out there. They formed over
(02:21):
billions of years from the same proto planetary dust that
orbited the Sun and eventually formed the planets and moons
of our Solar System. Some of those asteroids were formed
just by particles of dust crashing into one another and
forming larger particles eventually growing into small rocks, and then
you know, less small rocks into big honking rocks. Some
(02:46):
formed after other planetary bodies had collisions and ejected matter
out into space as a result. But in general, you've
got a bunch of rocky stuff floating around the Solar System.
And I said there are many different types of asteroids,
and that is true, but it's also a bit complicated,
and that's because there's actually more than one way to
(03:06):
classify asteroids. You could classify them by their location. For example,
most of the asteroids we know about are in orbit
in what we call the asteroid belt appropriately enough, and
that's between the orbits of Mars and Jubiter. Now there
are other asteroids called near Earth asteroids, which, as the
(03:26):
name suggests, have orbits that take them close to the Earth.
These can sometimes pose what is called a problem, And
by a problem, I mean that a sufficiently large enough
asteroid could cause global devastation should collide with Earth, you know,
fun times. But we can also classify asteroids based on
what they are made out of. There are three major
(03:49):
classes of asteroids. The most common type that we know
about is C type or chondrite asteroids. These are made
up of silicate rocks and clay and have some carbonaceous
material in them. They are in the outer regions of
the asteroid belt. They are dark and thus hard to spot,
but they make up about of all known asteroids. Then
(04:13):
you've got S type or silicaceous asteroids or stony asteroids.
They consist of nickel, iron, and silicate materials primarily, and
they tend to be brighter than C type asteroids, and
most of those inhabit the inner asteroid belt. Then you've
got M type or metallic asteroids that are made primarily
(04:34):
from nickel and iron. They make up about eight percent
of all known asteroids, and they're mostly in the middle
region of the asteroid belt, and they also are brighter
than C type asteroids. Now those are the major types,
but they're also A type asteroids, B type, D type asteroids,
and so on. These represent rare or extremely rare types
(04:55):
of asteroids, and some are considered subtypes of the more
common variants. Some are kind of a split between different
major types. They're different enough to justify a subclassification. There's
somewhere in between the major versions. Benu, the asteroid that
osiris rex orbits, is one of these smaller subclassifications. It's
(05:17):
technically a B type asteroid. B type asteroids are a
subcategory of C type asteroids, which, as I just mentioned,
make up the vast majority of the known asteroids that
we've observed so far. That's one of the reasons the
Osiris REX team selected Benu, But I'll get back to that.
So asteroid mining, that's the name suggests, involves harvesting resources
(05:41):
from asteroids. Those resources could include volatile substances like trapped
gases within the molecular structure of the asteroid. Metals are
another possible resource, and asteroid mining could go after stuff
like platinum. Water is another big resource as it could
be used to produce rocket fuel, among other things. Most
(06:01):
deep space exploration strategies include some sort of asteroid mining component,
as it would mean making use of materials that are
already out in space to support the mission, which reduces
the need to carry more stuff with you when you're
launching from Earth. In fact, the concept of asteroid mining
is all about being able to leverage stuff out in
space while we're exploring or colonizing space. It's not about
(06:26):
bringing resources back to Earth, but rather limiting the resources
we need need to bring from Earth out into space.
And that's a big deal. The more massive the payload
of your spacecraft, the more fuel you need to get
off the ground, and that could necessitate the design of
new launch vehicles if the payload you're looking at is
(06:48):
heavy enough and the fuel itself is really expensive. So
if you can reduce the amount of fuel you need,
then you bring down the complexity and the cost of
a launch. And it's absolutely necessary to do something like
asteroid mining if we want to send people to places
like Mars and have them be able to get back again.
If those who travel to Mars can make use of
(07:09):
the resources that are actually on the Red planet using
techniques that we've perfected through asteroid mining, then they can
do that to produce their own rocket fuel. They can
manufacture their own fuel they need to return to Earth.
There would be no need to carry twice as much
fuel on board to make a round trip. Moreover, harvesting
resources from asteroids could yield us the materials we need
(07:31):
to build structures out in space in the first place.
So instead of launching spacecraft that are carrying components and
modules that then have to be assemboled in orbit or
in deep space, we could get the raw materials in
space itself and establish orbiting manufacturing facilities. Again, we wouldn't
have to take stuff from Earth incident on into space,
(07:53):
because we'd be harvesting all that raw materials from other
bodies in space. Of course, all of this is easy
to talk about in the hypothetical. Actually building the equipment
that can make this possible is another matter entirely, and
while we can be theoretical about it, being practical requires
a whole lot more work. Oh, cyrus Rex and other
(08:15):
projects are building the foundation upon which we can actually
construct this asteroid mining future. So let's talk more about
that mission and the spacecraft. One thing the team had
to do must figure out which asteroid to select for
a mission in the first place. I mean, there are
millions of them. So how did they settle on Benu
(08:36):
metaphorically speaking, since the spacecraft has not, as the recording
of this podcast, literally settled on the asteroid. There are
more than half a million identified asteroids in the Solar System.
So why did the team choose Benu? Well, first, they
decided the asteroid couldn't be too far away that would
make it impractical to journey there. So the further way
(08:59):
the asteroid, the harder it is to get there, and
the potential for failure increases as distance increases. For that reason,
the team wanted to focus on asteroids that fall into
the category of near Earth objects or an EOS. Near
is a relative term, mind you, they're not just a
quick jaunt away. To be classified as an n EO,
(09:21):
the object has to be within one point three astronomical
units from the Sun in their orbits. A single astronomical
unit is the distance between the Earth and the Sun.
That means it's about ninety three million miles or around
a hundred fifty million kilometers. That makes one point three
astronomical units at around a hundred twenty million, eight hundred
(09:44):
thousand miles or one four million, five hundred thousand kilometers. So,
as I said, near is relative, but that's because space
is really big. An EOS can sometimes pose a potential
hazard to Earth. These asteroids are in a subcategory called
potentially hazardous asteroids or p h a's, and ben Wu
(10:08):
happens to be one of those. There is a small
chance that the asteroid could collide with Earth late in
the twenty second century, and by small chance, I mean
we currently estimate the odds of it happening are less
than point zero four percent. But still, when you're looking
at the potential for devastation. Any chance isn't you know great?
(10:32):
But back to choosing Benu. So Benu was one of
just a d two asteroids that had an earth like
orbit with low eccentricity, so it's got a nice stable
orbit that's pretty similar to Earth's. Out of all the
thousands there are more than seven thousand year Earth objects
that they were looking at, only two met that criteria,
(10:56):
and ben Wu was one of those two. Next, the
team looked at the size of the remaining candidates, because
smaller asteroids rotate faster than larger ones, and fast rotating
asteroids can eject material out into space and that could
pose a problem for any spacecraft that is flying nearby
or trying to make contact with that asteroid. So the
(11:18):
team needed to rule out any asteroids that had a
diameter smaller than two hundreds because they would probably be
spinning too quickly. That eliminated all but twenty six of
the candidates ben who's diameter, by the way, is approximately
five and we have to use approximations in part because
Benu is a big, lumpy rock, so it all depends
upon where you're doing the measuring. Then there's the asteroids composition.
(11:42):
Out of the twenty six remaining in NEOs that were
under consideration, not much was known about fourteen of them,
so those were out. Out of the twelve remaining in eos,
only five are known to be rich in carbon and
other materials like volatiles, and therefore they have the potential
to have or anic materials sort of the building blocks
of life, not necessarily any proof of life forms on
(12:06):
the asteroid itself, but rather the basic components that together
could form a life. And so Benu and four other
asteroids were left on the list, and the team eventually
chose Benu from those few remaining and eos that were
under consideration. To complete a full orbit, it takes Bnu
about four hundred thirty six Earth days to go around
(12:29):
the Sun. Every half dozen years, Benu gets fairly close
to Earth, as the respective orbits of Benu and our
planet bring the two bodies within point zero zero two
astronomical units of each other. And as I said late
in the twenty second century, that's going to happen about
eight times, really fairly close to one another. But the
(12:53):
chance of a collision is is fairly really small, not
fairly small, less than point zero four percent. Still it's
a possibility. Now when we come back, I'll talk more
about the spacecraft itself before moving on to talk of
other technology and development. They'll bring us close to mining asteroids.
But first let's take a quick break. So let's talk
(13:19):
about o Cyrus Rex. First, let's talk about the name. Now,
I'm pretty confident that the name was one of those
where they came up with the name first and then
retroactively worked to turn that name into an acronym. Osirius
is the name of the ancient Egyptian god of the
afterlife and rebirth. Benu, the asteroid, happens to also have
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an Egyptian name, is named after a mythical bird in
ancient Egyptian lore, which played a part in creating the
world itself. So my guess is that the team was
working on this spacecraft, they selected Benu as the asteroid
they were going to visit, and Benu was named back
in two thousand twelve, so this is probably all happening
around the same time, and then they decided to go
(14:04):
with a similar theme and they chose an Egyptian reference
when they named their own spacecraft. That's a guess on
my part. Now, officially, the acronym stands for Origins, Spectral Interpretation,
Resource Identification, Security, Regular Leath, Explorer Cyrus REX, and the
(14:26):
X is in lower case because explorer all the other
letters are upper case. Now, I think my guess that
it was a retroactive acronym, as a fair one with
a name like that doesn't just roll off the tongue.
But hey, I could be totally wrong. This is again
just a guess on my part. Maybe they came up
with the long name and then someone looked at the
initials and said hang on, and it was just gissemn. Well,
(14:51):
I'll talk about the equipment on O Cyrus REX in
a second, but first I want to talk about the
overall mission. The spacecraft launched as part of the payload
on a Atlas five rocket on September eight, two thousand sixteen.
About a year later, the Earth gave Osiris REX an
assist by way of a gravity boost. So Osiris kind
(15:12):
of entered into an orbit, and then in order to
put it on a intercept trajectory with Benu. As it
was completing this orbit and getting close to the Earth,
it passed near the Earth so it would get pulled
by Earth's gravity then used a deflection strategy to put
itself on it's its intercept trajectory with Benu and was
(15:36):
able to get a little speed boost that way. Another
year later, in August two eighteen, the spacecraft transitioned into
the approach phase. At this point, Osiris Rex was still
about two million kilometers or one point two million miles
away from Benu. This phase actually lasted several months and
(15:57):
would end on December third, two thousand eight team when
no Cyrus Rex was able to get a visual on
Benu and was starting to create a sort of map
for the team on Earth to study. Starting on December third, ten,
the spacecraft entered into the next phase, the preliminary survey phase.
At a distance of about seven kilometers or four point
(16:19):
three miles, a Cirrus Rex passed over the north pole,
equator and south pole of Benu a total of five times,
and the data was sent back to Earth so that
scientists could estimate things like the asteroids mass and get
a better idea for the shape of the asteroids, also
to learn how the asteroid was spinning in orbit, which
is all valuable information for planning the upcoming phases that
(16:42):
would follow next, on December thirty first, two thousand eighteen,
the spacecraft entered into a very close orbit with Benu,
which ranged from about one point six to two point
one kilometers in altitude above the asteroid or about point
nine nine to one point three miles not at the time,
this was the closest spacecraft had ever orbited a small
(17:05):
body in space, so this was the first time Osiris
REX set a record for that. And it was in
this phase that the navigation technique switched from being star
based in other words, it was using the stars to
navigate where it was going to becoming a landmarked based
navigation system, so now it's in respect to the asteroid itself.
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During this phase, the navigation team on Earth could practice
maneuvering the spacecraft near the asteroid, which would be important
for the later phases as well. So each phase kind
of set the ground for the next phase, and that
next phase began on February two thousand nineteen. This one
was called the Detailed Survey Baseball Diamond phase and had
(17:48):
gotten that name early in the mission design process because
originally the plan was to have Osiris REX move around
in orbit in a shape reminiscent of a baseball diamond,
and the actual pattern changed during the mission design phase,
but the name stuck. Now. The purpose of those movements
is to produce a bunch of viewing angles of Benu's
(18:09):
surface to get a better idea not just of where
Osiris Rex might eventually make contact, but also teach us
more about what the asteroid is actually made out of.
Next was the detailed Survey Equatorial Stations phase, and that
phase was much more about finding an appropriate collection site
for the Osiris REX to take samples from the asteroid.
(18:31):
I'll cover that actual process in just a second, and
it's super cool, but before that can happen, the team
has to determine the right spot for it. The goal
of the phase was to select up to twelve potential
collection sites on the surface of Benu. This has proven
to be trickier than you think. As I mentioned earlier,
Benu is a bumpy little sucker, so finding spots that
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are smooth and flat enough has been really challenging. The
team also has looked for evidence of loose regulars on
the surface of the asteroid. That's the loose soil. Essentially,
it's the stuff that the spacecraft will ultimately try to
collect on its sampling mission. The current phase that it's
in is orbital B. That's what broke the record that
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Osiris REX had set during the orbital A phase by
getting even closer to Benu. Right now, Osiris REX is
gathering information that will be used to create as accurate
a three D model for the asteroids shape as we
can manage. It will also conduct a radio science experiment
during this phase, and the result of this phase is
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meant to help the team determine which of those up
to twelve candidates would be best to focus on to
really eliminate ten of those twelve. So they're looking at
three criteria to select two potential landing spots. Those three
criteria are safety, sample ability, and science value. So it
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needs to be able to score high on all three
of those to be considered a potential collection site. And
as I said, they will select two of them. One
of them will be the prime target, their number one choice,
and the second is their backup. Now, at the conclusion
of this phase of Cyrus REX will then enter a
(20:21):
third orbit, orbit See, but this one will actually be
further out than orbit will be, so orbit will See
will move o Cyrus Rex to about one point three
kilometers above the surface of the asteroid as it examines
particles on and around venue. Next, o Cirius Rex will
enter into a recon phase where it will take a
(20:41):
very close look at those two potential collection sites, and
it's going to pass at an altitude of around two
d or seven hundred thirty eight feet above benus surface.
At that distance, the cameras aboard the Osiris Rex can
focus on objects as small as two meters in size.
(21:01):
The team can then determine if their initial site or
the backup site would be the best bet for the
actual collection, so they can narrow their choices down to
their actual you know end target. Before committing to that course,
the team will hold a couple of rehearsal events. They
will practice moving the spacecraft out of its orbit to
(21:21):
fly above the landing site, initially at an altitude of
about four hundred ten feet or one ms above the
collection site. Then they will maneuver the Osiris Rex back
into orbit. On the second rehearsal, the Osiris Rex will
actually descend further and hover over the collection site, well
(21:44):
over it, but still over it, before returning to orbit again.
After all of that, if assuing all of it goes
well at showtime. The critical phase is called TAG, and
TAG stands for touch and go, which should happen in Also,
i've heard people erroneously say that the game tag stands
(22:05):
for touch and go. That does not appear to be true.
The etymology of the word is older than that particular
phrase has been, so I don't think that that really
applies to the game tag, but it certainly applies to
this process with os Cyrus Rex. I'll explain what the
(22:26):
collection process is in just a moment. But after that phase,
the spacecraft's thrusters will push it back from Beneu to
a safe distance and it will kind of chill out
at that safe distance until March one. At that time
it will enter into the return cruise phase, and that's
what's supposed to bring Osiris Rex home. So why is
(22:47):
it waiting. It's waiting because, just as I've talked about,
when it comes to going from Earth to Mars, you
have to wait for the orbits of the different bodies
to aligne up properly to make the trip up as
efficiently as possible. So that won't happen until March one. Uh,
and that's when Osiris REX can start its intercept trajectory
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to Earth anyway onto the spacecraft itself with its solar
panels deployed. It measures six point two meters or twenty
point to five feet in length. It's two point four
meters wide. Uh, that's essentially eight feet, and it's sort
of like a rectangular prism, so the width measured either
(23:32):
left right or up down with respect to its length
is the same. It weighs two thousand rams when full
of fuel. That's about four thousand, six hundred fifty pounds,
so it's hefty when it's fully fuelled. The spacecraft is
home to five science instruments as well as the system
called tag SAM. Tag SAM stands for Touch and Goes
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Sample Acquisition Mechanism, so this is the actual device that's
going to do the collecting. The tag SAM is part
of the Osiris REX that will actually make contact with Benu,
and it looks kind of like a pogo stick that
extends out from one side of the spacecraft, but this
is a pretty powerful pogo stick. Inside of the tag
(24:18):
SAM is a mechanism that will direct a jet of
nitrogen gas to quote fluid ize regular to allow the
sample head to capture granular material, while contact pads capture
fine material end quote. So it's blasting the surface with
this jet of gas and then collecting what ends up
flying out. The whole process should last about five seconds.
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Then springs in the tag SAM will actually expand, pushing
Osiris rex off the surface of Benu, so you could
argue it really is like a high tech pogo stick.
The team on Earth will initiate commands to make Osiris
rex spin, and the purpose for that is to figure
out how much stuff did it actually collect. They will
monitor the change in the spacecraft's inertia, and by looking
(25:05):
at the difference in inertia between when the spacecraft was
had before it had taken the sample and after it
had taken the sample, they can then deduce how much
material it actually collected, and if it's not enough, the
spacecraft actually has enough nitrogen gas to make two more
attempts before it runs out, so it can do three
of these collection leaps before it is done. Mechanisms in
(25:30):
the spacecraft will move the sample from the tag SAM
tool to a sample return capsule UH or s r C.
It's essentially a protected container designed to be retrieved when
Osiris rex gets back to Earth. More on that than
a bit. As for the other scientific instruments I did
mention there were five of them. They include the O
(25:51):
Cam's instrument Suite that's a collection of special cameras that
are taking all those amazing images of Benu right now,
and honestly, if you have and scends, go online and
search for Benu b in b E n n U
asteroid because the most recent photos are pretty amazing. Then
they have a laser altimeter or o l A that
(26:15):
is using lasers to create a detailed three D map
of bnus shape. And I've talked about how these worked before,
but the basic idea is that you have a laser
and you have a sensor, So you fire the laser
and the sensor picks up the reflections of the laser
after the laser has made contact with the surface of
whatever it is you're aiming at. By looking at how
long it took for the laser to travel from the
(26:36):
laser point to hit the the surface of the substance
and then back for the sensor to pick it up,
you can tell how far away or how close something is.
So if you do this a lot, if you know
how far away you are from the object, and you
do this a lot across the surface of the object.
You can use that information to make a detailed map
(26:56):
of the surface features of whatever that object is. And
we do this on Earth too, but it's very useful
out in space. And then you've got the thermal emission
spectrometer or O t E s OTIS. The spectrometer's job
is to analyze the mineral and chemical composition of Benu,
as well as to measure the surface temperature of the asteroid. Next,
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you've got the Visible and Infrared Spectrometer or OVERS. The
O in all of these, by the way, stands for
osiris REX. This particular instrument is going to measure light
from Binu both in the visible and near infrared spectrum,
and that analysis could indicate the presence of stuff like
water or organic material. Finally, there's the regular X ray
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imaging spectrometer or REXUS, which will image X ray emissions
from Benu, and that will tell us which elements are
most abundant on the asteroid, So it kind of gives
us an idea of how much concentration there is of
each element that's present. So in March two, THO one.
Assuming everything went well, the Osiris Rex spacecraft will begin
(28:02):
its journey back to Earth. They will enter into an
orbit around the Sun that again will bring it close
enough to the Earth for the next part of the
mission to commence, and that will happen in the fall
of twenty twenty three, so from twenty to the spring
of one to the fall of tree it will be
in this orbit. So it takes a long time to
get around in space, particularly when all the stuff out
(28:24):
in space insists on moving around in orbits and stuff.
So when it's close enough, then the spacecraft is going
to jettison that sample return capsule to put it on
an intercept trajectory towards Earth, like an actual collision course
towards Earth. Then Osiris Rex will follow a deflection maneuver
and place itself in a stable orbit around the Sun
(28:47):
where it won't be in the way of anything. The
capsule will in our Earth's atmosphere, and when it reaches
an altitude of twenty point eight miles or thirty three
point five kilometers, it will deploy a drogue pair a
shoote and when it descends to one point nine miles
in altitude or three kilometers. Then it will deploy the
(29:07):
main parachute. Assuming all goes as planned, it should touch
down in Utah on Septembree. Pretty amazing to have it
all plotted out to the day, this far in advance,
and it just tells you how exact these processes have
to be. Now. Upon retrieval again, assuming everything's gone well,
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the contents of that capsule will undergo incredible scrutiny and analysis.
Researchers will look for any signs of organic compounds. In
the end, will learn a lot about stuff that could
come in useful for many future missions, including dealing with
potentially hazardous asteroids and asteroid mining. More on that in
(29:49):
just a bit, but first let's take another quick break.
While o Cyrus rex was sending back incredible photos of
Benu from just a few hundred meters away, other space
news was also focusing on asteroids and our future with them,
(30:11):
NASA awarded a grant to a company called trans Astronautica Corporation.
Sometimes it's just referred to as Transastra. The company is
designing flight systems that follow the asteroid provided institute supplies
structure or APIs architecture, as the name implies, This type
of technology is meant to harvest materials from asteroids in
(30:35):
space rather than taking the asteroids somewhere else to mind them.
And there are a lot of different designs that follow
this particular concept. Some of them are landers or rovers
that can use my various mining techniques to pull stuff
out from asteroids or collect regularly from the surface. But
transastras design is a little different. They call their approach
(30:57):
the Mini B system, and really they have a whole
collection of different devices of different sizes that fall under
this general category. The Mini BE itself is sort of
a prototype, proof of concept spacecraft. It's a two m spacecraft,
so it's not it's not as big as the future
(31:18):
versions are going to be, but it will serve as
a test bed for a type of mining called optical mining,
meant to largely extracts stuff like volatiles and water from asteroids. Now,
in the case with the Mini BE, it will work
with a simulated asteroid to make sure that everything is
(31:38):
working the way it's supposed to uh. The many BE
will capture the simulated asteroid the way the B spacecraft
are are designed. They have a large chamber that is
essentially made up of a bag, and so it's a
flexible bag that is open on one end. Inside the
(32:02):
bag is a grapple net. It's a net that actually
has actuators on it, so we can open and close,
and the bag itself can also close. So the idea
is that the many be will end up capturing this
simulated asteroid in a way that the larger bee family
will also do. So this is how the process works,
(32:25):
because it's pretty fascinating. I watched a whole video on
this and I was really blown away by the approach.
So first of all, you have to imagine that this
spacecraft is approaching a small asteroid and the asteroids rotating.
As I mentioned earlier, Benu rotates, so asteroid is rotating,
and so you are approaching along the axis of rotation.
(32:46):
So it's it's like you're coming directly at the end
of its rotation. Uh. So you're watching it turn and
let's say a clockwise motion just for the sake of
imagining this. Uh. The spacecraft first matches speed with the asteroid,
so they can then very slowly approach so that this
(33:08):
bag and the net inside the bag can fit over
the asteroid. The idea is that you position the spacecraft
so that the net is ready to grapple with the
asteroid itself. However, before that happens, the spacecraft matches the
rotation of the asteroid itself, so that way from the
(33:30):
frame of reference of the asteroid, it appears that the
spacecraft isn't moving at all because they both are matching
their rotation together. That this is very important because otherwise, obviously,
if the spacecraft is not rotating with at the same
speed as the asteroid, then if the net tries to
grip is gonna twist. So by spinning the spacecraft at
(33:53):
the same speed that the asteroid is spinning, they look
still in reference to one another. Remember this is relativity.
It's all dependent upon your frame of reference. Now, at
that point, the spacecraft can close the net which grips
on to the asteroid, and then the capture bag that's
(34:13):
on the outside of this net also closes, and this
provides a protective barrier that actually completely encapsulates the asteroid
inside it. Then the thrusters on the spacecraft will fire
to counteract the rotation, so it's kind of like a
break You start to stop the rotation of the asteroid
(34:33):
and use those to orient the spacecraft in relation to
the sun, because the sun provides the power for the
actual mining operation. Remember I mentioned it was optical mining.
Well here's where that plays in. The spacecraft will have
reflectors that will concentrate sunlight so it can be directed
and focused on the surface of in this case, the
(34:56):
simulated asteroid, but in future Jan's assuming this works, it
will be on actual asteroids, and that light will heat
up the surface of the asteroid, which will force it
to release volatiles and water, and it will break up
the asteroid. Actually, if you heat it up enough and
that molecular structure starts to break down, it's kind of
like using a magnifying glass to concentrate sunlight and use
(35:20):
it to burn wood. Collected gases will go into inflatable
containers that will have passive cooling from space itself. You know,
space is very cold, so essentially you have these bags
that are uh the outside is open to space, and
you collect all the gases and water vapor in there,
and because of the incredibly cold temperatures, all that heat
(35:43):
radiates away and you end up with bags of ice
ice not just of water, but also these volatile gases.
The slag, so In other words, the rocks and the
other materials will go into collection bags at the base
of the large capture bags, So there's going to be
sort of assorting mechanism that will shoot this regular these
(36:06):
rocks and the metals and things that are the solids
from the asteroid into these collection bags. And ideally one
of these B devices would be able to do this
to a few different asteroids before it would need to
be emptied. But the goal of the MINIB isn't to
go into full operation. It's really just to show that
this approach is viable and could work on a much
(36:29):
larger scale, and that's where the bigger versions of the
B family would come in. So if the MINIB proves
to be effective, then we might see the larger ones.
One of those is called the honey Bee that would
be able to mine asteroids that measure about ten meters
in size, So that's a pretty big capture bag and
(36:50):
net that would have to be used, and like the
Mini B I would capture asteroids in that same process.
And this is important for lots of reasons. One is
that you don't want to lose any of those resources
as they get released during the optical mining process, and
other is that as an asteroid breaks down, it is
going to break into lots of little pieces. Capturing the
asteroid means those pieces aren't just floating off and forming
(37:11):
a cloud of space junk that could be a potential
hazard for future missions. So it's very important to to
contain all of that. And the company actually proposes gathering
up all the unusable rubble, the stuff that can't be
used for construction purposes or used for metal or whatever
it may be. You take all that other stuff what
would just be useless slag from this mining process, and
(37:35):
then fill up tubes with this slag. So imagine long
plastic tubes, these containers that are just full of all
this asteroid slag. Then they could use those tubes filled
with slag as shielding for space stations or habitats. The
material could act as a method to absorb harmful radiation,
(37:56):
which is a pretty creative way to handle the waste
byproduct of a mining process. I do wonder how sustainable
that is in the long term, because I imagine at
some point you wouldn't need to shield anything else out there, right,
you would have built enough shields while you're still mining
asteroids for their materials. But maybe I'm thinking too small,
and maybe the future will include unimaginable expansion into space,
(38:20):
and maybe that's more realistic considering the history of humanity
on Earth. It's just hard for me to imagine right now.
Next in the line of flight systems as the Queen
be which would be able to capture asteroids of up
to forty meters in size, and like the smaller cousins,
it would follow the exact same process, you know, the
general procedure of encapsulating and then optically mining asteroids would
(38:43):
just be bigger. The thrusters on the B devices will
actually use harvested water to provide thrust, so the B
devices will be able to continue to operate in space
as they extract resources from asteroids, and you don't have
to worry about having a huge amount of fuel on board.
And they actually do this in a pretty simple way.
They're not using the water as rocket fuel precisely. What
(39:07):
happens is they will funnel the water into a chamber,
and that chamber will be exposed to focused sunlight, and
that will heat up the water past its boiling point,
which will turn it into a gas, and the gas
will force its way out of a nozzle that's at
the base of the chamber and that creates thrust. So
the bees will only use a small amount of the
(39:28):
water that they collect as propellant, and the rest of
the water would be delivered to fuel depots in space,
and that water can then be used to produce rocket fuel.
If it works, it could help form the basis for
deep space exploration. Rather than shooting fuel up into space
from Earth, will just make it out there in space
in the first place. Now, these spacecraft could lead to
(39:50):
the development of more space mining equipment, as well as
plans for the fabrication facilities that would turn slag into
usable construction material and space, not to mention those fuel
depots that would be needed to make use of the
harvested volatiles and water. So this is just one small
piece in a very large puzzle that we're going to
have to construct in order to make asteroid mining a
(40:13):
practical technology and part of an overall working strategy for
deep space exploration and colonization. And the minib system is
just one proposed approach. I don't mean to say it's
the only way this is going to happen. It's just
one proposal that got some funding. There are lots of
other ones out there too, and some of them don't
(40:34):
use optical mining. Some of them use different methods. There
are several private companies exploring the possibilities and testing out
different systems or subsystems with the goal of asteroid mining
in mind. We're likely to see some combination of several
different approaches should it turn out that it's a viable pursuit.
I doubt any single way is going to become the
(40:55):
only method we rely upon. The prospects look fairly promising,
but there's still a lot of work to be done,
and if it is successful, we could see new efforts
to travel to more distant locations like Mars and beyond.
Being able to replenish resources while out in space would
mitigate one of the major challenges standing in our way,
(41:17):
though it would be cavalier to suggest it's the biggest
or most important challenge. There are lots of others to consider,
such as protecting human explorers from the dangers of cosmic radiation.
Plus there's that whole thing that space is always trying
to kill you. It's hard to get around that. But
we're making some great progress and I'm excited to see
where this goes from here. I doubt I'll ever get
(41:40):
a chance to venture into space, but it's still inspiring
to think that future generations might have that option. Of course,
we'll need to make sure we're making the right choices
here on Earth right now to make that a future possibility.
But you guys listen to tech stuff, so you're already
on the right path for that kind of thing, right anyway,
(42:01):
that wraps up this discussion of o Cyrus Rex and
the Mini B system and asteroid mining. I'm sure I'll
do another episode about how to handle potentially hazardous asteroids.
I did an episode about that in the past as well.
But you know, there are always developments that add to
our understanding. Certain tactics become more likely, others become more unlikely.
(42:25):
So I'll do a follow up episode at some point
in the meantime. If any of you have any suggestions
for future episodes, you can send me an email the
addresses tech stuff at how stuff works dot com or
pop and buy our website that's tech stuff podcast dot com.
You're going to find an archive of all of our
past episodes there, including the original asteroid mining episode. We
(42:48):
recorded back in two thousand and twelve, as well as
links to our social media presence and to our online store,
where every purchase you make goes to help the show
and we greatly appreciate it, and I'll talk to you
again really soon. Yeah. Tech Stuff is a production of
(43:10):
I Heart Radio's How Stuff Works. For more podcasts from
my heart Radio, visit the I heart Radio app, Apple Podcasts,
or wherever you listen to your favorite shows.
Welcome to tech Stuff, a production of I Heart Radios,
How Stuff Works. Hey there, and welcome to tech Stuff.
I'm your host Jonathan Strickland. I'm an executive producer with
how Stuff Rex and I Heart Radio and I love
all things tech. And On June twelve, two thousand nineteen,
a small spacecraft called Osiris Rex set a new out
(00:29):
of this world record. That record was for entering the
closest orbit around a small planetary body, and the record
was previously held by well Osirius Rex, but now it
was really extra super close, like six d eight meters
or less than unred feet close. The planetary body is
(00:55):
the asteroid Bnu b e nn you. It will eventually
get even closer to Benu. The plan is for the
spacecraft to make contact with the asteroid for the purposes
of collecting a sample, then it will begin its journey
back to Earth. Right now, it's taking a series of
images of the asteroid, partly so that a team back
(01:16):
here on Earth can evaluate the best spot to make
that point of contact. It turns out Benu is a
bit more bumpy than we anticipated, so finding a spot
that will be suitable for a Cyrus Rex and given
the best chance for a successful mission is no small
task in of itself. That's the short version of the story.
(01:37):
But today I want to talk more about the mission,
the technology, and the long term plan to mine asteroids
as part of the overall strategy for deep space operations.
And this isn't the first time I've talked about asteroid mining.
Way back in June two thousand twelve, my co host
Chris Palette and I talked about this idea, and we
(01:58):
also replayed that episode in May two thousand nineteen. So
some of this might sound a bit familiar since I'll
be tackling a similar subject, but it's well overdue for
a follow up, So let's begin with a high level
view of what asteroid mining is all about. There are
many different types of asteroids out there. They formed over
(02:21):
billions of years from the same proto planetary dust that
orbited the Sun and eventually formed the planets and moons
of our Solar System. Some of those asteroids were formed
just by particles of dust crashing into one another and
forming larger particles eventually growing into small rocks, and then
you know, less small rocks into big honking rocks. Some
(02:46):
formed after other planetary bodies had collisions and ejected matter
out into space as a result. But in general, you've
got a bunch of rocky stuff floating around the Solar System.
And I said there are many different types of asteroids,
and that is true, but it's also a bit complicated,
and that's because there's actually more than one way to
(03:06):
classify asteroids. You could classify them by their location. For example,
most of the asteroids we know about are in orbit
in what we call the asteroid belt appropriately enough, and
that's between the orbits of Mars and Jubiter. Now there
are other asteroids called near Earth asteroids, which, as the
(03:26):
name suggests, have orbits that take them close to the Earth.
These can sometimes pose what is called a problem, And
by a problem, I mean that a sufficiently large enough
asteroid could cause global devastation should collide with Earth, you know,
fun times. But we can also classify asteroids based on
what they are made out of. There are three major
(03:49):
classes of asteroids. The most common type that we know
about is C type or chondrite asteroids. These are made
up of silicate rocks and clay and have some carbonaceous
material in them. They are in the outer regions of
the asteroid belt. They are dark and thus hard to spot,
but they make up about of all known asteroids. Then
(04:13):
you've got S type or silicaceous asteroids or stony asteroids.
They consist of nickel, iron, and silicate materials primarily, and
they tend to be brighter than C type asteroids, and
most of those inhabit the inner asteroid belt. Then you've
got M type or metallic asteroids that are made primarily
(04:34):
from nickel and iron. They make up about eight percent
of all known asteroids, and they're mostly in the middle
region of the asteroid belt, and they also are brighter
than C type asteroids. Now those are the major types,
but they're also A type asteroids, B type, D type asteroids,
and so on. These represent rare or extremely rare types
(04:55):
of asteroids, and some are considered subtypes of the more
common variants. Some are kind of a split between different
major types. They're different enough to justify a subclassification. There's
somewhere in between the major versions. Benu, the asteroid that
osiris rex orbits, is one of these smaller subclassifications. It's
(05:17):
technically a B type asteroid. B type asteroids are a
subcategory of C type asteroids, which, as I just mentioned,
make up the vast majority of the known asteroids that
we've observed so far. That's one of the reasons the
Osiris REX team selected Benu, But I'll get back to that.
So asteroid mining, that's the name suggests, involves harvesting resources
(05:41):
from asteroids. Those resources could include volatile substances like trapped
gases within the molecular structure of the asteroid. Metals are
another possible resource, and asteroid mining could go after stuff
like platinum. Water is another big resource as it could
be used to produce rocket fuel, among other things. Most
(06:01):
deep space exploration strategies include some sort of asteroid mining component,
as it would mean making use of materials that are
already out in space to support the mission, which reduces
the need to carry more stuff with you when you're
launching from Earth. In fact, the concept of asteroid mining
is all about being able to leverage stuff out in
space while we're exploring or colonizing space. It's not about
(06:26):
bringing resources back to Earth, but rather limiting the resources
we need need to bring from Earth out into space.
And that's a big deal. The more massive the payload
of your spacecraft, the more fuel you need to get
off the ground, and that could necessitate the design of
new launch vehicles if the payload you're looking at is
(06:48):
heavy enough and the fuel itself is really expensive. So
if you can reduce the amount of fuel you need,
then you bring down the complexity and the cost of
a launch. And it's absolutely necessary to do something like
asteroid mining if we want to send people to places
like Mars and have them be able to get back again.
If those who travel to Mars can make use of
(07:09):
the resources that are actually on the Red planet using
techniques that we've perfected through asteroid mining, then they can
do that to produce their own rocket fuel. They can
manufacture their own fuel they need to return to Earth.
There would be no need to carry twice as much
fuel on board to make a round trip. Moreover, harvesting
resources from asteroids could yield us the materials we need
(07:31):
to build structures out in space in the first place.
So instead of launching spacecraft that are carrying components and
modules that then have to be assemboled in orbit or
in deep space, we could get the raw materials in
space itself and establish orbiting manufacturing facilities. Again, we wouldn't
have to take stuff from Earth incident on into space,
(07:53):
because we'd be harvesting all that raw materials from other
bodies in space. Of course, all of this is easy
to talk about in the hypothetical. Actually building the equipment
that can make this possible is another matter entirely, and
while we can be theoretical about it, being practical requires
a whole lot more work. Oh, cyrus Rex and other
(08:15):
projects are building the foundation upon which we can actually
construct this asteroid mining future. So let's talk more about
that mission and the spacecraft. One thing the team had
to do must figure out which asteroid to select for
a mission in the first place. I mean, there are
millions of them. So how did they settle on Benu
(08:36):
metaphorically speaking, since the spacecraft has not, as the recording
of this podcast, literally settled on the asteroid. There are
more than half a million identified asteroids in the Solar System.
So why did the team choose Benu? Well, first, they
decided the asteroid couldn't be too far away that would
make it impractical to journey there. So the further way
(08:59):
the asteroid, the harder it is to get there, and
the potential for failure increases as distance increases. For that reason,
the team wanted to focus on asteroids that fall into
the category of near Earth objects or an EOS. Near
is a relative term, mind you, they're not just a
quick jaunt away. To be classified as an n EO,
(09:21):
the object has to be within one point three astronomical
units from the Sun in their orbits. A single astronomical
unit is the distance between the Earth and the Sun.
That means it's about ninety three million miles or around
a hundred fifty million kilometers. That makes one point three
astronomical units at around a hundred twenty million, eight hundred
(09:44):
thousand miles or one four million, five hundred thousand kilometers. So,
as I said, near is relative, but that's because space
is really big. An EOS can sometimes pose a potential
hazard to Earth. These asteroids are in a subcategory called
potentially hazardous asteroids or p h a's, and ben Wu
(10:08):
happens to be one of those. There is a small
chance that the asteroid could collide with Earth late in
the twenty second century, and by small chance, I mean
we currently estimate the odds of it happening are less
than point zero four percent. But still, when you're looking
at the potential for devastation. Any chance isn't you know great?
(10:32):
But back to choosing Benu. So Benu was one of
just a d two asteroids that had an earth like
orbit with low eccentricity, so it's got a nice stable
orbit that's pretty similar to Earth's. Out of all the
thousands there are more than seven thousand year Earth objects
that they were looking at, only two met that criteria,
(10:56):
and ben Wu was one of those two. Next, the
team looked at the size of the remaining candidates, because
smaller asteroids rotate faster than larger ones, and fast rotating
asteroids can eject material out into space and that could
pose a problem for any spacecraft that is flying nearby
or trying to make contact with that asteroid. So the
(11:18):
team needed to rule out any asteroids that had a
diameter smaller than two hundreds because they would probably be
spinning too quickly. That eliminated all but twenty six of
the candidates ben who's diameter, by the way, is approximately
five and we have to use approximations in part because
Benu is a big, lumpy rock, so it all depends
upon where you're doing the measuring. Then there's the asteroids composition.
(11:42):
Out of the twenty six remaining in NEOs that were
under consideration, not much was known about fourteen of them,
so those were out. Out of the twelve remaining in eos,
only five are known to be rich in carbon and
other materials like volatiles, and therefore they have the potential
to have or anic materials sort of the building blocks
of life, not necessarily any proof of life forms on
(12:06):
the asteroid itself, but rather the basic components that together
could form a life. And so Benu and four other
asteroids were left on the list, and the team eventually
chose Benu from those few remaining and eos that were
under consideration. To complete a full orbit, it takes Bnu
about four hundred thirty six Earth days to go around
(12:29):
the Sun. Every half dozen years, Benu gets fairly close
to Earth, as the respective orbits of Benu and our
planet bring the two bodies within point zero zero two
astronomical units of each other. And as I said late
in the twenty second century, that's going to happen about
eight times, really fairly close to one another. But the
(12:53):
chance of a collision is is fairly really small, not
fairly small, less than point zero four percent. Still it's
a possibility. Now when we come back, I'll talk more
about the spacecraft itself before moving on to talk of
other technology and development. They'll bring us close to mining asteroids.
But first let's take a quick break. So let's talk
(13:19):
about o Cyrus Rex. First, let's talk about the name. Now,
I'm pretty confident that the name was one of those
where they came up with the name first and then
retroactively worked to turn that name into an acronym. Osirius
is the name of the ancient Egyptian god of the
afterlife and rebirth. Benu, the asteroid, happens to also have
(13:42):
an Egyptian name, is named after a mythical bird in
ancient Egyptian lore, which played a part in creating the
world itself. So my guess is that the team was
working on this spacecraft, they selected Benu as the asteroid
they were going to visit, and Benu was named back
in two thousand twelve, so this is probably all happening
around the same time, and then they decided to go
(14:04):
with a similar theme and they chose an Egyptian reference
when they named their own spacecraft. That's a guess on
my part. Now, officially, the acronym stands for Origins, Spectral Interpretation,
Resource Identification, Security, Regular Leath, Explorer Cyrus REX, and the
(14:26):
X is in lower case because explorer all the other
letters are upper case. Now, I think my guess that
it was a retroactive acronym, as a fair one with
a name like that doesn't just roll off the tongue.
But hey, I could be totally wrong. This is again
just a guess on my part. Maybe they came up
with the long name and then someone looked at the
initials and said hang on, and it was just gissemn. Well,
(14:51):
I'll talk about the equipment on O Cyrus REX in
a second, but first I want to talk about the
overall mission. The spacecraft launched as part of the payload
on a Atlas five rocket on September eight, two thousand sixteen.
About a year later, the Earth gave Osiris REX an
assist by way of a gravity boost. So Osiris kind
(15:12):
of entered into an orbit, and then in order to
put it on a intercept trajectory with Benu. As it
was completing this orbit and getting close to the Earth,
it passed near the Earth so it would get pulled
by Earth's gravity then used a deflection strategy to put
itself on it's its intercept trajectory with Benu and was
(15:36):
able to get a little speed boost that way. Another
year later, in August two eighteen, the spacecraft transitioned into
the approach phase. At this point, Osiris Rex was still
about two million kilometers or one point two million miles
away from Benu. This phase actually lasted several months and
(15:57):
would end on December third, two thousand eight team when
no Cyrus Rex was able to get a visual on
Benu and was starting to create a sort of map
for the team on Earth to study. Starting on December third, ten,
the spacecraft entered into the next phase, the preliminary survey phase.
At a distance of about seven kilometers or four point
(16:19):
three miles, a Cirrus Rex passed over the north pole,
equator and south pole of Benu a total of five times,
and the data was sent back to Earth so that
scientists could estimate things like the asteroids mass and get
a better idea for the shape of the asteroids, also
to learn how the asteroid was spinning in orbit, which
is all valuable information for planning the upcoming phases that
(16:42):
would follow next, on December thirty first, two thousand eighteen,
the spacecraft entered into a very close orbit with Benu,
which ranged from about one point six to two point
one kilometers in altitude above the asteroid or about point
nine nine to one point three miles not at the time,
this was the closest spacecraft had ever orbited a small
(17:05):
body in space, so this was the first time Osiris
REX set a record for that. And it was in
this phase that the navigation technique switched from being star
based in other words, it was using the stars to
navigate where it was going to becoming a landmarked based
navigation system, so now it's in respect to the asteroid itself.
(17:26):
During this phase, the navigation team on Earth could practice
maneuvering the spacecraft near the asteroid, which would be important
for the later phases as well. So each phase kind
of set the ground for the next phase, and that
next phase began on February two thousand nineteen. This one
was called the Detailed Survey Baseball Diamond phase and had
(17:48):
gotten that name early in the mission design process because
originally the plan was to have Osiris REX move around
in orbit in a shape reminiscent of a baseball diamond,
and the actual pattern changed during the mission design phase,
but the name stuck. Now. The purpose of those movements
is to produce a bunch of viewing angles of Benu's
(18:09):
surface to get a better idea not just of where
Osiris Rex might eventually make contact, but also teach us
more about what the asteroid is actually made out of.
Next was the detailed Survey Equatorial Stations phase, and that
phase was much more about finding an appropriate collection site
for the Osiris REX to take samples from the asteroid.
(18:31):
I'll cover that actual process in just a second, and
it's super cool, but before that can happen, the team
has to determine the right spot for it. The goal
of the phase was to select up to twelve potential
collection sites on the surface of Benu. This has proven
to be trickier than you think. As I mentioned earlier,
Benu is a bumpy little sucker, so finding spots that
(18:56):
are smooth and flat enough has been really challenging. The
team also has looked for evidence of loose regulars on
the surface of the asteroid. That's the loose soil. Essentially,
it's the stuff that the spacecraft will ultimately try to
collect on its sampling mission. The current phase that it's
in is orbital B. That's what broke the record that
(19:19):
Osiris REX had set during the orbital A phase by
getting even closer to Benu. Right now, Osiris REX is
gathering information that will be used to create as accurate
a three D model for the asteroids shape as we
can manage. It will also conduct a radio science experiment
during this phase, and the result of this phase is
(19:39):
meant to help the team determine which of those up
to twelve candidates would be best to focus on to
really eliminate ten of those twelve. So they're looking at
three criteria to select two potential landing spots. Those three
criteria are safety, sample ability, and science value. So it
(20:01):
needs to be able to score high on all three
of those to be considered a potential collection site. And
as I said, they will select two of them. One
of them will be the prime target, their number one choice,
and the second is their backup. Now, at the conclusion
of this phase of Cyrus REX will then enter a
(20:21):
third orbit, orbit See, but this one will actually be
further out than orbit will be, so orbit will See
will move o Cyrus Rex to about one point three
kilometers above the surface of the asteroid as it examines
particles on and around venue. Next, o Cirius Rex will
enter into a recon phase where it will take a
(20:41):
very close look at those two potential collection sites, and
it's going to pass at an altitude of around two
d or seven hundred thirty eight feet above benus surface.
At that distance, the cameras aboard the Osiris Rex can
focus on objects as small as two meters in size.
(21:01):
The team can then determine if their initial site or
the backup site would be the best bet for the
actual collection, so they can narrow their choices down to
their actual you know end target. Before committing to that course,
the team will hold a couple of rehearsal events. They
will practice moving the spacecraft out of its orbit to
(21:21):
fly above the landing site, initially at an altitude of
about four hundred ten feet or one ms above the
collection site. Then they will maneuver the Osiris Rex back
into orbit. On the second rehearsal, the Osiris Rex will
actually descend further and hover over the collection site, well
(21:44):
over it, but still over it, before returning to orbit again.
After all of that, if assuing all of it goes
well at showtime. The critical phase is called TAG, and
TAG stands for touch and go, which should happen in Also,
i've heard people erroneously say that the game tag stands
(22:05):
for touch and go. That does not appear to be true.
The etymology of the word is older than that particular
phrase has been, so I don't think that that really
applies to the game tag, but it certainly applies to
this process with os Cyrus Rex. I'll explain what the
(22:26):
collection process is in just a moment. But after that phase,
the spacecraft's thrusters will push it back from Beneu to
a safe distance and it will kind of chill out
at that safe distance until March one. At that time
it will enter into the return cruise phase, and that's
what's supposed to bring Osiris Rex home. So why is
(22:47):
it waiting. It's waiting because, just as I've talked about,
when it comes to going from Earth to Mars, you
have to wait for the orbits of the different bodies
to aligne up properly to make the trip up as
efficiently as possible. So that won't happen until March one. Uh,
and that's when Osiris REX can start its intercept trajectory
(23:11):
to Earth anyway onto the spacecraft itself with its solar
panels deployed. It measures six point two meters or twenty
point to five feet in length. It's two point four
meters wide. Uh, that's essentially eight feet, and it's sort
of like a rectangular prism, so the width measured either
(23:32):
left right or up down with respect to its length
is the same. It weighs two thousand rams when full
of fuel. That's about four thousand, six hundred fifty pounds,
so it's hefty when it's fully fuelled. The spacecraft is
home to five science instruments as well as the system
called tag SAM. Tag SAM stands for Touch and Goes
(23:55):
Sample Acquisition Mechanism, so this is the actual device that's
going to do the collecting. The tag SAM is part
of the Osiris REX that will actually make contact with Benu,
and it looks kind of like a pogo stick that
extends out from one side of the spacecraft, but this
is a pretty powerful pogo stick. Inside of the tag
(24:18):
SAM is a mechanism that will direct a jet of
nitrogen gas to quote fluid ize regular to allow the
sample head to capture granular material, while contact pads capture
fine material end quote. So it's blasting the surface with
this jet of gas and then collecting what ends up
flying out. The whole process should last about five seconds.
(24:42):
Then springs in the tag SAM will actually expand, pushing
Osiris rex off the surface of Benu, so you could
argue it really is like a high tech pogo stick.
The team on Earth will initiate commands to make Osiris
rex spin, and the purpose for that is to figure
out how much stuff did it actually collect. They will
monitor the change in the spacecraft's inertia, and by looking
(25:05):
at the difference in inertia between when the spacecraft was
had before it had taken the sample and after it
had taken the sample, they can then deduce how much
material it actually collected, and if it's not enough, the
spacecraft actually has enough nitrogen gas to make two more
attempts before it runs out, so it can do three
of these collection leaps before it is done. Mechanisms in
(25:30):
the spacecraft will move the sample from the tag SAM
tool to a sample return capsule UH or s r C.
It's essentially a protected container designed to be retrieved when
Osiris rex gets back to Earth. More on that than
a bit. As for the other scientific instruments I did
mention there were five of them. They include the O
(25:51):
Cam's instrument Suite that's a collection of special cameras that
are taking all those amazing images of Benu right now,
and honestly, if you have and scends, go online and
search for Benu b in b E n n U
asteroid because the most recent photos are pretty amazing. Then
they have a laser altimeter or o l A that
(26:15):
is using lasers to create a detailed three D map
of bnus shape. And I've talked about how these worked before,
but the basic idea is that you have a laser
and you have a sensor, So you fire the laser
and the sensor picks up the reflections of the laser
after the laser has made contact with the surface of
whatever it is you're aiming at. By looking at how
long it took for the laser to travel from the
(26:36):
laser point to hit the the surface of the substance
and then back for the sensor to pick it up,
you can tell how far away or how close something is.
So if you do this a lot, if you know
how far away you are from the object, and you
do this a lot across the surface of the object.
You can use that information to make a detailed map
(26:56):
of the surface features of whatever that object is. And
we do this on Earth too, but it's very useful
out in space. And then you've got the thermal emission
spectrometer or O t E s OTIS. The spectrometer's job
is to analyze the mineral and chemical composition of Benu,
as well as to measure the surface temperature of the asteroid. Next,
(27:17):
you've got the Visible and Infrared Spectrometer or OVERS. The
O in all of these, by the way, stands for
osiris REX. This particular instrument is going to measure light
from Binu both in the visible and near infrared spectrum,
and that analysis could indicate the presence of stuff like
water or organic material. Finally, there's the regular X ray
(27:39):
imaging spectrometer or REXUS, which will image X ray emissions
from Benu, and that will tell us which elements are
most abundant on the asteroid, So it kind of gives
us an idea of how much concentration there is of
each element that's present. So in March two, THO one.
Assuming everything went well, the Osiris Rex spacecraft will begin
(28:02):
its journey back to Earth. They will enter into an
orbit around the Sun that again will bring it close
enough to the Earth for the next part of the
mission to commence, and that will happen in the fall
of twenty twenty three, so from twenty to the spring
of one to the fall of tree it will be
in this orbit. So it takes a long time to
get around in space, particularly when all the stuff out
(28:24):
in space insists on moving around in orbits and stuff.
So when it's close enough, then the spacecraft is going
to jettison that sample return capsule to put it on
an intercept trajectory towards Earth, like an actual collision course
towards Earth. Then Osiris Rex will follow a deflection maneuver
and place itself in a stable orbit around the Sun
(28:47):
where it won't be in the way of anything. The
capsule will in our Earth's atmosphere, and when it reaches
an altitude of twenty point eight miles or thirty three
point five kilometers, it will deploy a drogue pair a
shoote and when it descends to one point nine miles
in altitude or three kilometers. Then it will deploy the
(29:07):
main parachute. Assuming all goes as planned, it should touch
down in Utah on Septembree. Pretty amazing to have it
all plotted out to the day, this far in advance,
and it just tells you how exact these processes have
to be. Now. Upon retrieval again, assuming everything's gone well,
(29:28):
the contents of that capsule will undergo incredible scrutiny and analysis.
Researchers will look for any signs of organic compounds. In
the end, will learn a lot about stuff that could
come in useful for many future missions, including dealing with
potentially hazardous asteroids and asteroid mining. More on that in
(29:49):
just a bit, but first let's take another quick break.
While o Cyrus rex was sending back incredible photos of
Benu from just a few hundred meters away, other space
news was also focusing on asteroids and our future with them,
(30:11):
NASA awarded a grant to a company called trans Astronautica Corporation.
Sometimes it's just referred to as Transastra. The company is
designing flight systems that follow the asteroid provided institute supplies
structure or APIs architecture, as the name implies, This type
of technology is meant to harvest materials from asteroids in
(30:35):
space rather than taking the asteroids somewhere else to mind them.
And there are a lot of different designs that follow
this particular concept. Some of them are landers or rovers
that can use my various mining techniques to pull stuff
out from asteroids or collect regularly from the surface. But
transastras design is a little different. They call their approach
(30:57):
the Mini B system, and really they have a whole
collection of different devices of different sizes that fall under
this general category. The Mini BE itself is sort of
a prototype, proof of concept spacecraft. It's a two m spacecraft,
so it's not it's not as big as the future
(31:18):
versions are going to be, but it will serve as
a test bed for a type of mining called optical mining,
meant to largely extracts stuff like volatiles and water from asteroids. Now,
in the case with the Mini BE, it will work
with a simulated asteroid to make sure that everything is
(31:38):
working the way it's supposed to uh. The many BE
will capture the simulated asteroid the way the B spacecraft
are are designed. They have a large chamber that is
essentially made up of a bag, and so it's a
flexible bag that is open on one end. Inside the
(32:02):
bag is a grapple net. It's a net that actually
has actuators on it, so we can open and close,
and the bag itself can also close. So the idea
is that the many be will end up capturing this
simulated asteroid in a way that the larger bee family
will also do. So this is how the process works,
(32:25):
because it's pretty fascinating. I watched a whole video on
this and I was really blown away by the approach.
So first of all, you have to imagine that this
spacecraft is approaching a small asteroid and the asteroids rotating.
As I mentioned earlier, Benu rotates, so asteroid is rotating,
and so you are approaching along the axis of rotation.
(32:46):
So it's it's like you're coming directly at the end
of its rotation. Uh. So you're watching it turn and
let's say a clockwise motion just for the sake of
imagining this. Uh. The spacecraft first matches speed with the asteroid,
so they can then very slowly approach so that this
(33:08):
bag and the net inside the bag can fit over
the asteroid. The idea is that you position the spacecraft
so that the net is ready to grapple with the
asteroid itself. However, before that happens, the spacecraft matches the
rotation of the asteroid itself, so that way from the
(33:30):
frame of reference of the asteroid, it appears that the
spacecraft isn't moving at all because they both are matching
their rotation together. That this is very important because otherwise, obviously,
if the spacecraft is not rotating with at the same
speed as the asteroid, then if the net tries to
grip is gonna twist. So by spinning the spacecraft at
(33:53):
the same speed that the asteroid is spinning, they look
still in reference to one another. Remember this is relativity.
It's all dependent upon your frame of reference. Now, at
that point, the spacecraft can close the net which grips
on to the asteroid, and then the capture bag that's
(34:13):
on the outside of this net also closes, and this
provides a protective barrier that actually completely encapsulates the asteroid
inside it. Then the thrusters on the spacecraft will fire
to counteract the rotation, so it's kind of like a
break You start to stop the rotation of the asteroid
(34:33):
and use those to orient the spacecraft in relation to
the sun, because the sun provides the power for the
actual mining operation. Remember I mentioned it was optical mining.
Well here's where that plays in. The spacecraft will have
reflectors that will concentrate sunlight so it can be directed
and focused on the surface of in this case, the
(34:56):
simulated asteroid, but in future Jan's assuming this works, it
will be on actual asteroids, and that light will heat
up the surface of the asteroid, which will force it
to release volatiles and water, and it will break up
the asteroid. Actually, if you heat it up enough and
that molecular structure starts to break down, it's kind of
like using a magnifying glass to concentrate sunlight and use
(35:20):
it to burn wood. Collected gases will go into inflatable
containers that will have passive cooling from space itself. You know,
space is very cold, so essentially you have these bags
that are uh the outside is open to space, and
you collect all the gases and water vapor in there,
and because of the incredibly cold temperatures, all that heat
(35:43):
radiates away and you end up with bags of ice
ice not just of water, but also these volatile gases.
The slag, so In other words, the rocks and the
other materials will go into collection bags at the base
of the large capture bags, So there's going to be
sort of assorting mechanism that will shoot this regular these
(36:06):
rocks and the metals and things that are the solids
from the asteroid into these collection bags. And ideally one
of these B devices would be able to do this
to a few different asteroids before it would need to
be emptied. But the goal of the MINIB isn't to
go into full operation. It's really just to show that
this approach is viable and could work on a much
(36:29):
larger scale, and that's where the bigger versions of the
B family would come in. So if the MINIB proves
to be effective, then we might see the larger ones.
One of those is called the honey Bee that would
be able to mine asteroids that measure about ten meters
in size, So that's a pretty big capture bag and
(36:50):
net that would have to be used, and like the
Mini B I would capture asteroids in that same process.
And this is important for lots of reasons. One is
that you don't want to lose any of those resources
as they get released during the optical mining process, and
other is that as an asteroid breaks down, it is
going to break into lots of little pieces. Capturing the
asteroid means those pieces aren't just floating off and forming
(37:11):
a cloud of space junk that could be a potential
hazard for future missions. So it's very important to to
contain all of that. And the company actually proposes gathering
up all the unusable rubble, the stuff that can't be
used for construction purposes or used for metal or whatever
it may be. You take all that other stuff what
would just be useless slag from this mining process, and
(37:35):
then fill up tubes with this slag. So imagine long
plastic tubes, these containers that are just full of all
this asteroid slag. Then they could use those tubes filled
with slag as shielding for space stations or habitats. The
material could act as a method to absorb harmful radiation,
(37:56):
which is a pretty creative way to handle the waste
byproduct of a mining process. I do wonder how sustainable
that is in the long term, because I imagine at
some point you wouldn't need to shield anything else out there, right,
you would have built enough shields while you're still mining
asteroids for their materials. But maybe I'm thinking too small,
and maybe the future will include unimaginable expansion into space,
(38:20):
and maybe that's more realistic considering the history of humanity
on Earth. It's just hard for me to imagine right now.
Next in the line of flight systems as the Queen
be which would be able to capture asteroids of up
to forty meters in size, and like the smaller cousins,
it would follow the exact same process, you know, the
general procedure of encapsulating and then optically mining asteroids would
(38:43):
just be bigger. The thrusters on the B devices will
actually use harvested water to provide thrust, so the B
devices will be able to continue to operate in space
as they extract resources from asteroids, and you don't have
to worry about having a huge amount of fuel on board.
And they actually do this in a pretty simple way.
They're not using the water as rocket fuel precisely. What
(39:07):
happens is they will funnel the water into a chamber,
and that chamber will be exposed to focused sunlight, and
that will heat up the water past its boiling point,
which will turn it into a gas, and the gas
will force its way out of a nozzle that's at
the base of the chamber and that creates thrust. So
the bees will only use a small amount of the
(39:28):
water that they collect as propellant, and the rest of
the water would be delivered to fuel depots in space,
and that water can then be used to produce rocket fuel.
If it works, it could help form the basis for
deep space exploration. Rather than shooting fuel up into space
from Earth, will just make it out there in space
in the first place. Now, these spacecraft could lead to
(39:50):
the development of more space mining equipment, as well as
plans for the fabrication facilities that would turn slag into
usable construction material and space, not to mention those fuel
depots that would be needed to make use of the
harvested volatiles and water. So this is just one small
piece in a very large puzzle that we're going to
have to construct in order to make asteroid mining a
(40:13):
practical technology and part of an overall working strategy for
deep space exploration and colonization. And the minib system is
just one proposed approach. I don't mean to say it's
the only way this is going to happen. It's just
one proposal that got some funding. There are lots of
other ones out there too, and some of them don't
(40:34):
use optical mining. Some of them use different methods. There
are several private companies exploring the possibilities and testing out
different systems or subsystems with the goal of asteroid mining
in mind. We're likely to see some combination of several
different approaches should it turn out that it's a viable pursuit.
I doubt any single way is going to become the
(40:55):
only method we rely upon. The prospects look fairly promising,
but there's still a lot of work to be done,
and if it is successful, we could see new efforts
to travel to more distant locations like Mars and beyond.
Being able to replenish resources while out in space would
mitigate one of the major challenges standing in our way,
(41:17):
though it would be cavalier to suggest it's the biggest
or most important challenge. There are lots of others to consider,
such as protecting human explorers from the dangers of cosmic radiation.
Plus there's that whole thing that space is always trying
to kill you. It's hard to get around that. But
we're making some great progress and I'm excited to see
where this goes from here. I doubt I'll ever get
(41:40):
a chance to venture into space, but it's still inspiring
to think that future generations might have that option. Of course,
we'll need to make sure we're making the right choices
here on Earth right now to make that a future possibility.
But you guys listen to tech stuff, so you're already
on the right path for that kind of thing, right anyway,
(42:01):
that wraps up this discussion of o Cyrus Rex and
the Mini B system and asteroid mining. I'm sure I'll
do another episode about how to handle potentially hazardous asteroids.
I did an episode about that in the past as well.
But you know, there are always developments that add to
our understanding. Certain tactics become more likely, others become more unlikely.
(42:25):
So I'll do a follow up episode at some point
in the meantime. If any of you have any suggestions
for future episodes, you can send me an email the
addresses tech stuff at how stuff works dot com or
pop and buy our website that's tech stuff podcast dot com.
You're going to find an archive of all of our
past episodes there, including the original asteroid mining episode. We
(42:48):
recorded back in two thousand and twelve, as well as
links to our social media presence and to our online store,
where every purchase you make goes to help the show
and we greatly appreciate it, and I'll talk to you
again really soon. Yeah. Tech Stuff is a production of
(43:10):
I Heart Radio's How Stuff Works. For more podcasts from
my heart Radio, visit the I heart Radio app, Apple Podcasts,
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