Asteroid Bennu is a carbon
rich asteroid that's made of leftovers of the early solar system.
So it's a junk pile that we can go to and get a sample back and get a firsthand
look of what was going on 4.5 billion years ago.
We wanted an asteroid
that was, we could get to and back from, in the lifespan of the team.
That's nice.
One that that we could use, a launch vehicle that exists and we could afford,
and then that puts us in the area of, of near-Earth asteroids.
We needed one that that didn't have an inclination that was too high.
We're not too much out of the plane of the Earth's orbit.
So we get there, and then we needed an asteroid
that was large enough so we could, navigate around.
It wouldn't spin too fast.
And we needed an asteroid that had spectra that
told us
it was organic rich. And finally, an asteroid that we had understandings of.
And of those are five left, and Bennu was the one that we understood the most.
The first look at at Bennu.
We were comparing, what we saw in the laboratory versus
what we saw on the spacecraft, that was published last year.
These papers, we have a pair of papers that looked at the,
the minerals found on the sample in greater depth,
as well as the organic compounds found in the sample.
The minerals tell us that this was a very wet world
that dried
out leaving evaporates, leaving,
salt deposits, in essence, baking soda and table salt.
And then the organics tell us that this was, an ammonia rich, world
that that must have been cold, at its in its origins.
And the salts tell us that
it was sort of room temperature at the last, stage of its origins.
It tells us that it
has amino acids, which are racemic, equal left and right handedness,
nucleobases. All the stuff of they expect to see,
in the formation of life scenarios, but no life itself.
So that's very, very interesting.
There are lots of surprises in the sample, one of which was it has very high
ammonia, relative to meteorites we've looked at, among among the highest.
And, this is a case where, I was concerned about contamination.
The spacecraft uses hydrazine model propellant thrusters,
which shoot out a jet of of ammonia, nitrogen, hydrogen gas.
How do we know the ammonia we found isn't contamination?
Well, we had the foresight to collect some of the same propellant
that that was on the spacecraft when it was being loaded in Florida before
launch in 2016.
We analyzed that in the laboratory for its its isotopic signature.
And compare that with the ammonia
we found in the sample and found out that they are quite distinct
and that the the high ammonia we see is not spacecraft contamination.
It's actually indigenous, to the to the asteroid.
And that tells us that came from a cold environment.
Initially, the rocks, formed beyond the orbit of Saturn.
We also found amino acids, which are racemic, equal left and right,
which was a surprise to me
because other meteorites, which are very water rich,
show an excess of left handed amino acids of some certain ones
here, they're racemic. They're equal left and right.
And so that,
I thought I had that answer figured out, but I don't.
So there's lots more questions to ask, of this sample
and of other of other samples that we can look at.
There's a lot of nitrogen found in biology,
which is abundant in the Bennu sample.
Amino acids, nuclear bases,
organic acids.
We found small ones, like, formic acid and acetic acid,
things of that sort in the sample, which are also common in biology,
there are phosphates, which are abundant in biology,
though in, in a different format.
We we found a brine, or evidence of an ancient brine,
which is alkaline, which is basic,
salty and full of organic compounds, which are the ingredients
that many believe were important for the origin of life.
So a question that I've been asking myself is, why didn't life form on Bennu?
It had the phosphate, it had the organics, it had the water.
It was alkaline.
It had the right salts and minerals.
But there is absolutely no evidence of biology in the Bennu samples.
No evidence,
chemically and no evidence microscopically.
So what went wrong?
And Bennu did not have enough time, did not have an atmosphere.
Are our hypothesis about what life needs wrong?
Wow. There's a lot to study.
Bennu was a pile leftover from the early solar system.
It's carbon rich.
It's it has lots of ammonia.
It has lots of organic compounds.
It has, these evaporated, salts and minerals.
It tells us that these were available in the early solar system,
that things like it would have been bombarding
the early Earth or Mars, Enceladus, Europa, Ceres,
what have you. And that that the chemistry that happened here
could have happened to these other, wet, alkaline, ocean water environments.
So perhaps, the ingredients for life were common.
Life seems to be difficult.
It formed on Earth.
It didn't form on Bennu.
We'll find out someday
if it if there's evidence for it on Mars or elsewhere on the solar system.
But the ingredients seem to be widespread.
Although Bennu contains racemic amino acids that equal left and right
handedness, as opposed to an excess of left has been seen in some meteorites.
So maybe, Bennu wasn’t as as clement an environment
for the origin of life based on on the amino acids
or maybe our theories about what needs to get life
going were wrong, and we have to reexamine them.
So finally, samples
come back to my laboratory, last November.
And, it's been thrilling to be able to finally see
this work paying a lot, paying off for, for my lab.
And of course, the most exciting part for me is the legacy of the sample.
More than three quarters of the sample is archived.
The Johnson Space Center in Houston,
also at the Japanese and soon Canadian space agencies
so that people can request samples if they're have ideas that we
that we're not examining.
And in fact, people not yet born can use techniques,
not yet invented, tests, answer questions we haven't even asked.
And so the legacy for decades to come of the sample is the most exciting part.
And it's been worth that 20 year journey.
We have the luxury
of being but being able to go to this asteroid and get a sample.
Yes, that's close enough.
We have the technology, we have the willpower to get it.
And we can
then perhaps extrapolate to other areas we can't get to, at least not yet.
And so, bring back a sample to study in a laboratory tells us,
what actually happened 4.5 billion years ago so that we can modify
our experiments in the laboratory so we can adjust where we look on,
on other worlds, on the solar system, so we can modify our theories and models
of the chemistry, physics and geology that go into life.
And so,
Bennu has, a complicated history that we're just now beginning to peel back
that, that there were pulses of different fluids
moving through through Bennu of at different times in its history.
And that's, will be a fascinating story to tell from
before the solar system began, all the way up to when the sample landed on Earth.
That's the archive Bennu has for us.
One of the first
discoveries we made was that we, in fact, went to the right asteroid.
It was everything we hoped and more.
It was, organic, rich.
It was carbon rich.
It was very primitive.
But it wasn't like anything else we had in our collection.
It is somewhat like Ryugu, but definitely different.
There's some, like, some meteorites we have, but definitely different.
It is so fragile that if it landed on Earth,
we wouldn't be able to to collect it.
It would fall apart.
The the the minerals, would be ruined
by humidity and certainly by rain.
So this sample would not be achievable without going there.
And, this unique object
gives us a whole new perspective on the whole of the solar system.
That was only possible because of OSIRIS-REx.