In October 2020 on this blog I published a post entitled "NASA's Asteroid-Stuff Retrieval Mission: The Spilling Boondoggle." Below are some of the things I said in that post:
"The OSIRIS-REx mission is a billion-dollar NASA mission designed to retrieve some matter from an asteroid, and return it to Earth. It is rather hard for me to imagine a less worthy way to spend a billion dollars. Asteroids are lifeless dry rocks in space that contain nothing very interesting. We already have a pretty good idea of what makes up an asteroid. Many meteorites have hit the Earth, and scientists who have analyzed their composition have a basis for inferring the element composition of asteroids. A science site tells us that most meteorites 'are fragments of asteroids.'
Nobody is interested in the exact composition of asteroids other than a very tiny tribe of scientists such as planetary geologists. If we get back a little asteroid material from the mission, the results will be a complete yawn to 99.9% of the people who read the results in their science news feeds. It will be some very boring result such as '80% iron and 20% a combination of nickel, iridium, palladium, and magnesium.' "
By now the OSIRIS-REx mission has completed. The automated spacecraft gathered a sample of dirt from the asteroid Bennu, and returned the sample to Earth in September 2023. There was then an almost comical glitch in which scientists were long unable to open the top of the sample container. Finally in January 2024 a news story reported that success had finally occurred, telling us this:
NASA FINALLY RIPS LID OFF STUBBORN ASTEROID SAMPLE
IT'S TAKEN THEM OVER THREE MONTHS
We read this truly ridiculous account in the January 2024 news story:
"In an October update, NASA' noted that 'two of the 35 fasteners on the TAGSAM head could not be removed.' Now, just over 3.5 months later, the main container is finally open. 'Finally having the TAGSAM head open and full access to the returned Bennu samples is a monumental achievement that reflects the unwavering dedication and ingenuity of our team,' said principal investigator Dante Lauretta in a statement."
Can we imagine a more laughable case of scientist boasting? Scientists took three months to get some screws off of a container (something the average Joe could do in maybe ten minutes), and then a scientist is boasting that this is a "monumental achievement." What can we expect next -- that the next time someone at NASA changes a light bulb, this will be hailed in a NASA press release as an "epic history-making accomplishment"?
By now scientists have had many months to analyze the contents of the sample returned from the asteroid Bennu. The first long publicly accessible analysis of the sample is contained in the 73-page paper "Asteroid (101955) Bennu in the Laboratory: Properties of the Sample Collected by OSIRIS-REx" which you can read using the link here. Here is the "dull as dishwater" abstract of the paper's contents:
"On 24 September 2023, NASA’s OSIRIS-REx mission dropped a capsule to Earth containing ~120 g of pristine carbonaceous regolith from Bennu. We describe the delivery and initial allocation of this asteroid sample and introduce its bulk physical, chemical, and mineralogical properties from early analyses. The regolith is very dark overall, with higher reflectance inclusions and particles interspersed. Particle sizes range from sub-micron dust to a stone ~3.5 cm long. Millimeter-scale and larger stones typically have hummocky or angular morphologies. A subset of the stones appears mottled by brighter material that occurs as veins and crusts. Hummocky stones have the lowest densities and mottled stones have the highest. Remote sensing of Bennu’s surface detected hydrated phyllosilicates, magnetite, organic compounds, carbonates, and scarce anhydrous silicates, all of which the sample confirms. We also find sulfides, presolar grains, and, less expectedly, Na-rich phosphates, as well as other trace phases. The sample’s composition and mineralogy indicate substantial aqueous alteration and resemble those of Ryugu and the most chemically primitive, low-petrologic-type carbonaceous chondrites. Nevertheless, we find distinct hydrogen, nitrogen, and oxygen isotopic compositions, and some of the material we analyzed is enriched in fluid-mobile elements. Our findings underscore the value of sample return — especially for low-density material that may not readily survive atmospheric entry — and lay the groundwork for more comprehensive analyses."
The quote above ends with a false statement. Far from underscoring the value of sample return, the reported results suggest that retrieving tiny samples from asteroids is a waste of money. Nothing of any biological interest is reported. Notably, the paper fails to make any mention of any amino acids detected. Amino acids are the simplest chemical components of living things.
By May 2024 scientists had already had months to look at the soil sample from Bennu, and had found no good evidence of anything of biological interest. But in that month the Smithsonian Institute had a speaker announcement making the bogus claim that "analysis of the sample promises to provide insights into the formation of the Earth as a habitable world and the origin of life." This was one of very many similar statements pushing groundless hype about this mission.
One preprint paper co-authored by D. Glavin claims to have found amino acids in a Bennu sample at the extremely low trace amount of "70 nmol/g" which is only 70 nanomoles per gram. Ordinary soil has about .1 moles per gram, and 70 nanomoles is only .00000007 moles per gram. Probably almost all of the reported amount is from earthly contamination. We cannot have any confidence that such a finding tells us anything about whether multiple types of protein-related amino acids exist in trace amounts on asteroids.
Scientists use methods to prevent contamination when analyzing samples from space, but there is no reason to believe that such efforts are entirely effective. There are two potential sources of contamination. A spacecraft may contain trace amounts of amino acids from Earth when it lands on another planet or asteroid. Once a sample is returned to Earth, there are endless possibilities for contamination, because amino acids are everywhere on Earth.
The paper here ("OSIRIS-REx Contamination Control Strategy and Implementation") tells us about methods to prevent microbes and amino acids from existing on the Osiris/REx spacecraft that gathered the sample from the asteroid Bennu. It claims, "To return a pristine sample, the OSIRIS-REx spacecraft sampling hardware was maintained at level 100 A/2 and <180 ng/cm2 of amino acids and hydrazine on the sampler head through precision cleaning, control of materials, and vigilance." This is a mention of some standard of cleanliness that was a target level, and we have no guarantee that such a target level of cleanliness was actually obtained. Moreover, the standard of cleanliness mentioned is less than 180 nanograms per square centimeter. Under such a standard, we might expect that you would get tiniest trace amounts results as reported by Glavin (merely 70 nanomoles per gram) from trace amounts from Earth that were left on the spacecraft when it reached the asteroid Bennu.
Then there is another possibility for contamination: contamination during the analysis of a soil sample on Earth. Such contamination is all but impossible to prevent, giving that amino acids and microbes are floating around everywhere on Earth. Sterilization can be used to kill microbes, but sterilization does not remove amino acids.
The paper above states this:
"Some level of contamination and alteration of the sample is probable. Decisions and actions which impact sample cleanliness can occur at any time in the lifecycle of spacecraft fabrication, operations, and sample curation."
An article at the site Salon tells us that when a soil sample was analyzed from the asteroid Ryugu, under conditions supposed to prevent contamination, the sample was contaminated not merely by amino acids but by microbes. We are referred to a paper entitled "Rapid colonization of a space-returned Ryugu sample by terrestrial microorganisms." We read this:
"The population statistics indicate an extant microbial community originating through terrestrial contamination. The discovery emphasizes that terrestrial biota can rapidly colonize extraterrestrial specimens even given contamination control precautions."
If entire microbes (millions of times bigger than amino acids) can get through the contamination measures of scientists analyzing samples from asteroids, then can we have any confidence that most of the amino acids detected at the tiniest trace amounts of only 70 nanomoles per gram actually came from an asteroid rather than from terrestrial contamination? No, we cannot.
There is a technique used to guess whether amino acids in a meteorite or asteroid sample arose from earthly contamination. The technique is to try to check for whether the amino acids are racemic. Some amino acids are racemic if they have an equal number of left-handed and right-hand versions of the amino acids. One of very many accidentally unachievable features of earthly life is what is called homochirality: that in living organisms all amino acids are left-handed, contrary to what we would expect by chance. Producing amino acids in a laboratory produces equal amounts of left-handed and right-handed amino acids. By checking whether amino acids in a meteorite or asteroid sample are racemic, you can get a good hint as to whether they arose from earthy contamination (the amino acids in earthly proteins are all non-racemic).
The paper by Glavin et. al. merely claims that one of the nine protein-related amino acids it detected was racemic: the amino acid alanine. It makes no such claim about the other protein-related amino acids it found. So we have no reason to think that any of the protein-related amino acids other than alanine came from the asteroid Bennu itself, and we are left with no abundance estimate for how much alanine was found. We can presume that the abundance was very much less than the reported very tiny, miniscule total of 70 nanomoles per gram, leaving you with a negligible abundance. Alanine is not one of the more complex amino acids used by proteins.
The bottom line is that no reliable results of any great biological interest have come from the Osiris/REx Bennu mission. The mission was as bad a boondoggle as I said it was in my 2020 post.