After spending 1,909 Mars suns on the red planet, NASA’s Curiosity rover suffered from a minor malfunction.
The robot’s drill stopped working while Curiosity was on Mars’ Vera Rubin ridge at the base of Mount Sharp. The rover had collected a sample of Mars dirt, and the team behind the mission decided to go a different route.
Instead of dropping the sample into one of the cups in the sample carousel, they dropped it into a cup filled with a chemical mixture. The molecules released from the cup were then captured and analyzed, revealing organic molecules on Mars that no space agency had previously discovered.
The researchers detailed their discovery in a study published Monday in the journal Nature astronomy.
Maëva Millan, a postdoctoral fellow at NASA’s Goddard Spaceflight Center and lead author of the new study, explains that the original motivation behind the experiment was to have a reference to future chemistry experiments performed on Mars samples.
“This experiment was certainly successful,” says Millan Vise versa. “Although we did not find what we were looking for, biosignatures, we showed that this technique is really promising.”
HERE IS THE BACKGROUND – NASA’s Curiosity rover landed on Gale Crater on August 6, 2012 and has been roaming the Martian terrain ever since.
The mission aims to search for signs of ancient life on Mars.
Although Mars is cold and barren today, it may once have had flowing rivers and pooling lakes. Scientists believe that the planet may have once been habitable and possibly hosted ancient microbial life in its early history.
To search for that life, scientists are looking for biosignatures on Mars – certain chemicals that may have been produced by some form of past or present life, be it microbes or something more complex.
Researchers are also searching for organic molecules. Organic molecules are considered the building blocks of life on Earth – which can be transferred to other places in the universe.
The Curiosity rover has previously discovered organic molecules buried in Mars sediments, but the new results add to the list of organic molecules on Mars, further strengthening the case of previous habitability.
WHAT IS NEW – In March 2017, Curiosity collected dirt samples from Bagnold Dune on Mars. Because Curiosity’s practice was out of order at the time, the team decided to perform a first of its kind experiment. The rover has 74 cups inside its stomach, and nine of these cups are filled with a chemical mixture.
“In the regular process, when we collect the sample with Curiosity’s robotic arm, we would drop it into one of these cups,” Millan says. “But in this case, we dropped the sample in one of the fields filled with chemical reagents.”
The team did not expect the sample to be rich in well-preserved organic molecules, as ionizing radiation had long hit the old soil.
But after testing the sample with the chemical mixture, the team behind the mission identified organic molecules never seen before on Mars. The two most important molecules were benzoic acid and ammonia.
Although these molecules are not biosignatures, they are good indicators of the presence of biosignatures.
“One of the things we tried to look for [when searching for] organic molecule on Mars is to understand Mars’ previous habitability and to look for bioindicators, ”says Millan.
WHAT’S NEXT – After identifying the organic molecules, the team aims to find their origin or “parent molecules.”
“Once we’ve found that, we can tell where they come from,” Millan says. “From now on, with all the molecules we have found on Mars, we have hypothesized that they could come from geological processes.”
But since Curiosity took the sample from Gale Crater, which is believed to have had water in the past, the molecules could be possible indicators of past habitability.
The team of scientists behind the study awaits the launch of the European Space Agency’s ExoMars mission in 2022 to collect more samples from Mars.
The perseverance rover also collects samples from the surface of Mars, which will later be brought to Earth to be analyzed inside a laboratory.
All the different Mars missions put together different pieces of the puzzle in the history of Mars, and whether the Red Planet has ever hosted life, and whether that life sprouted life on Earth.
Abstract: The wet chemical experiments on the sample analysis at the Mars instrument on NASA’s Curiosity rover were designed to facilitate gas chromatography mass spectrometry analyzes of polar molecules such as amino acids and carboxylic acids. Here we present the results of such a successful wet chemistry experiment on Mars sanded from the Bagnold dunes with the N-methyl-N- (tert-butyldimethylsilyl) trifluoroacetamide derivatizing agent. No amino acid derivatives were detected. However, chemically derivatized benzoic acid and ammonia were detected. Mass spectra matching derivatized phosphoric acid and phenol were present, as were several nitrogen-bearing molecules and as yet unidentified high molecular weight compounds. The origin of these compounds, including those that may be internal to the sample analysis at Mars’ background, is being investigated. This derivatization experiment on Mars has expanded the stock of molecules present in Mars samples and demonstrated a powerful tool to further enable the search for polar organic molecules of biotic or prebiotic relevance.