Keith’s note: According to the official NASA Mars 2020 website: “The Mars 2020 mission addresses high-priority science goals for Mars exploration, including key questions about the potential for life on Mars. The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself.”
That’s Astrobiology. Mars 2020 is an Astrobiology mission – the first overt Astrobiology mission since the twin Viking landers in 1976. Why doesn’t NASA call it an “Astrobiology mission”? Why doesn’t NASA even use the word “Astrobiology” on the Mars 2020 website – or elsewhere – to describe the mission? Yet the word appears in today’s Mars 2020 landing site press release.
Jezero Crater Announced As Mars 2020 Rover Landing Site
“The landing site in Jezero Crater offers geologically rich terrain, with landforms reaching as far back as 3.6 billion years old, that could potentially answer important questions in planetary evolution and astrobiology,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate. “Getting samples from this unique area will revolutionize how we think about Mars and its ability to harbor life.”
NASA learned the lesson of Viking well. If you promote a mission to Mars as searching for life, and fail to find it, you lose funding for a generation. NASA won’t promote a mission to Mars as a search for life on Mars until it is sure it will find life on Mars.
Except that NASA isn’t a monolithic organization. Some people don’t remember that lesson. Or aren’t so worried that they are extra careful about how they phrase things. Dr. Zurbuchen is from a heliophysics background, not astrobiology. I doubt he has those “failed to find life” concerns as deeply ingrained as other people.
And it isn’t clear to me if Mars 2020 would, technically, be an astrobiology mission. How much of that “potentially answer important questions in… astrobiology” involves caching samples for a future mission to return? Would a mission which simply collected samples of possible, astrobiological interest count as an astrobiology mission? None of the other instruments strike me as life finding ones.
There’s a huge difference between the Project Viking and the Mars 2020 Rover Project. Viking was looking for evidence of extant, current life on Mars and was designed accordingly. The Mars 2020 Rover is designed to look for signs of ancient life, ie, biosignatures and perhaps even microfossils, that can be scientifically investigated in depth back on Earth. There is a possibility, however slim, that Martian microbes could hitch-hike back to Earth in the rock and soil samples so extreme caution will be used. The 2020 Rover is also going to continue doing science investigations and experiments like MOXIE designed to pave the way for human exploration on Mars. So even if could be called an “Astrobiology Mission” that leaves out the other investigations. It’s certainly fair to ask the question about it being an “Astrobiology Mission” but what exactly is an Astrobiology mission? The entire Mars Exploration Program has at it’s core the desire to understand the habitability of Mars in the past and the present including the search for life. So in a sense the entire program is furthering astrobiology. But it’s also doing other kinds of investigations not directly life-oriented. Searching for life in the universe once again is one of other several specific goals of NASA but it’s not the only goal. Definitely an important one, though.
Viking also had other goals, but once scientists determined it produced a “false” return with its life experiment interest in future Mars missions disappeared. But what is interesting is that based on what we now know about Mars, it is quite possible Viking did find life there.
https://www.space.com/41689…
Life on Mars? 40 Years Later, Viking Lander Scientist Still Says ‘Yes’
By Leonard David
August 31, 2018 01:12pm ET
“Gilbert Levin was the principal investigator of the Vikings’ Labeled Release (LR) life-detection experiment. The instrument got positive responses at both landing locales. However, scientists did not reach a consensus on whether his results were proof of life.
In 1997, Levin concluded that the experiment had, indeed, detected life on Mars — and he has championed that viewpoint ever since.”
“Nevertheless, Schulze-Makuch said that any declaration of life on Mars still requires overwhelming evidence before being scientifically saluted. “Just think about how long it took before it was accepted that there was and still is liquid water on Mars!” he said.”
Hopefully when the BFS goes to Mars it will actually carry the instrumentation needed to see if life exists.
Since there’s no way to even attempt to sterilise BFS, it will contaminate the area around itself with Earth bacteria. There’s no way to get an uncontroversial life-detection from a BFS mission.
I think I could. Remember, the Viking orbiters weren’t subject to nearly the same sterilization requirements as the landers. The sterilized the landers, put them in a sealed container or “bioshield” and didn’t worry as much about the orbiters. You could take the same approach with a BFS mission. Fly a large and very capable, but robotic lander, sterilize it, encapsulate it, and use the huge cargo capacity of a BFS to get it to Mars. Release the lander on approach to Mars and put it down at a nice, comfortable distance from where the BFS plans to land. In fact, with the cargo capacity of a BFS, you could fly several of these, let’s call them “Biology Finding Landers” or BFL, on the same BFS mission. Other options include having them collect and encapsulate samples. Once sealed, they could be collected for lab analysis by humans, without risk of contamination.
Sure there is. Include the needed instrumentation to do a DNA analysis of any life found. If it uses different chemicals for the DNA, or the symmetry chemistry (Chirality) for the nucleic acids are different, its Martian. If they are the same you then test to see when it last had a common ancestor with Earth life. If its not within the last fifty years its Martian.
Really, if DNA analysis is able to identify the charateristics of the origin ancestor of life on Earth it will be able to tell Martians from Earthlings.
https://www.nytimes.com/201…
Meet Luca, the Ancestor of All Living Things
By Nicholas Wade
July 25, 2016
BTW did I also mention that scientists on Earth many cases don’t even survey organisms anymore? The just collect a sample of soil, or water and test directly for their DNA. Its everywhere.
https://oceanleadership.org…
Ancient DNA Found Hidden Below Sea Floor
May 10, 2013
If you understood how researchers derived LUCA, you would understand how dumb that comment is.
Molecular clocks only work by comparing two samples, and only return the “distance” between the samples. That’s it. Unless you have a sample of the contaminating microbe taken just before lift-off, you will never get a result of “50 years”. Hell if you compare random samples of Earthly bacteria, you don’t get a result of “50 years”, you get “billions of years”, so by your reasoning they are all from different planets.
Given how few bacteria/etc we’ve actually sequenced, and how many orders are present on any given surface, it’s perfectly reasonable to get result that a recent contaminant on Mars will have no common ancestor with known Earth bacteria all the way back to LUCA, 3.8 billion years ago.