Twelve years ago, Dante Lauretta, a budding meteorite scientist at the University of Arizona in Tucson, was close to a breakthrough. His team was examining carbon-rich meteorites and had detected whiffs of triphosphate—the “TP” in adenosine triphosphate, or ATP, the molecule that powers life. But they couldn’t nail it because of terrestrial contamination. One sample, for instance, came from a meteorite that had crashed into an Australian manure ditch. Lauretta needed something pristine. On 8 September, Lauretta will be a space flight away from getting his wish, with the launch of the $1 billion Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer (OSIRIS-REx). Although it won’t be the first spacecraft to bring asteroid dust back to Earth—Japan’s Hayabusa 1 returned several thousand grains of dust in 2010—the scoop of grit it delivers in 2023 could reveal new insights into the unaltered building blocks of the solar system and the types of amino acids and other organic molecules that asteroid impacts delivered to an early Earth. The samples will come from Bennu, a half-kilometer-wide asteroid that’s as black and dense as coal. It’s a “B-type” asteroid, one of the parent bodies suspected to be responsible for the carbon-rich meteorites that Lauretta studied. Its orbit at times brings it nearly as close to Earth as the moon, so astronomers have studied it well. Nevertheless, mystery remains. There’s a small chance, for instance, that a hint of blue in its reflection could point to a past episode of heating that might have destroyed the anticipated organic molecules. Upon arrival in August 2018, the spacecraft will survey Bennu from 240 meters above the surface. It will study the Yarkovsky effect, in which photons emitted from the sun-heated surface of a small, rotating asteroid generate a minuscule force that can alter its orbit. Because the effect varies greatly depending on subtle differences in shape and reflectivity, scientists want an opportunity to study it up close. The effect can also be used to trace asteroid orbits back in time, in order to identify the events that created them. Team scientists hope to confirm suspicions that Bennu was born hundreds of millions of years ago in collisions within the asteroid belt. http://www.sciencemag.org/news/2016/08/nasa-sample-asteroid-clues-life-earth
The Yarkovsky effect, creating thrust by rotating an absorbing body in sunlight in the right direction was thought to be an original idea, and patented. As it is, the Earth does it right, heating itself, an re-radiating on the west, the trailing side of the orbit, Venus rotates the wrong way for that, the really hot side would face into the orbit (after 165 days of exposure) . even the clouds seem to expand toward the forward side. so: To divert an asteroid, give it an off-center push, and let the sun do the rest of the work. or?
We may have forgotten it years ago, but Osiris-Rex is bringing back asteroid samples from Bennu. Its little reentry capsule is due to arrive in Utah tomorrow, Sunday Sept 24, 2023. Scientists will finally learn what the composition is of those weird powdery crushable rocks on its surface. https://www.nasa.gov/osiris-rex https://www.nasa.gov/press-release/nasa-finalizes-coverage-for-first-us-asteroid-sample-landing Live coverage will start on nasa-live at 7 AM PDT/10AM EDT. There will be a post-landing press conference at 5 PM EDT, which will also be on nasa-live. https://www.nasa.gov/nasalive
The little capsule (3-4 feet across) has successfully landed in the Utah desert west of Salt Lake City. Helicopters have landed and the recovery team is on scene. The actual sample container won't be opened at the landing site. Instead, the sealed container will be returned to Houston where clean-room facilities exist to avoid contamination of the contents. Even contact with Earth air could alter the chemistry of the contents.
I see, in the paper, that they expect to find carbonaceous material and hydrated minerals. But I was a bit concerned to see that temperatures >2000C were experienced during re-entry. I presume this relates to the outside rather than the inside of the capsule, but even so I wonder how much the heat may have altered the samples.
It seems the temperature of the sample will not go above 75°C . https://spaceflight101.com/osiris-rex/osiris-rex-sample-return-capsule/
Yeah, that's the heating experienced by the heat shield. I doubt if the sample container in the interior got any hotter than Bennu gets heated by the Sun. One of the press conference speakers said that when the backshell was removed, the interior looked pristine like before it launched.
Thanks, that link is very detailed and informative. Pretty impressive to be able to keep the sample below 75C under such conditions - though I suppose the period of exposure of the outside to 2000C+ is very short, so it's a matter of ensuring the rate of heat leakage is reduced sufficiently. After all, they did manage to get 3 men back from the Moon without the internal temperature rising to uncomfortable levels, though that was a far bigger capsule and so with better surface:volume ratio.
They are having some trouble opening it apparently. Material has already been accessed from the outside but the central box cannot be opened. I will update.
Welded itself shut due to the re-entry, perhaps? How amusing. I can picture then with tin-openers and angle grinders.
This link is from another forum. https://gizmodo.com/nasa-struggling-open-asteroid-sample-container-1850951047
Here is NASA’s blog on OSIRIS-Rex https://blogs.nasa.gov/osiris-rex/ At the moment the news (20 Oct 2023) is as Pinball’s post above^ Just to add from the blog:
They have finally opened it. https://www.gbnews.com/news/us/nasa-opens-asteroid-bennu-container-osiris-rex