Tag: Mars

In a study released today, the Curiosity science team announced that earlier drill samples revealed evidence of complex organic carbon molecules, the possible remains of past life.

To unlock organic molecules from the samples, the oven baked them to temperatures of between 600°C and 860°C—the range where a known contaminant disappeared—and fed the resulting fumes to a mass spectrometer, which can identify molecules by weight. The team picked up a welter of closely related organic signals reflecting dozens or hundreds of types of small carbon molecules, probably short rings and strands called aromatics and aliphatics, respectively. Only a few of the organic molecules, sulfur-bearing carbon rings called thiophenes, were abundant enough to be detected directly, Eigenbrode says.

The mass patterns looked like those generated on Earth by kerogen, a goopy fossil fuel building block that is found in rocks such as oil shale—a result the team tested by baking and breaking organic molecules in identical instruments on Earth, at Goddard. Kerogen is sometimes found with sulfur, which helps preserve it across billions of years; the Curiosity scientists think the sulfur compounds in their samples also explain the longevity of the Mars compounds.

Earth’s kerogen was formed when geologic forces compressed the ancient remains of algae and similar critters. It’s impossible to say whether ancient life explains the martian organics, however. Carbon-rich meteorites contain kerogenlike compounds, and constantly rain down on Mars. Or reactions driven by Mars’s ancient volcanoes could have formed the compounds from primordial carbon dioxide. Monica Grady, a planetary scientist at The Open University in Milton Keynes, U.K., believes the compounds somehow formed on Mars because she thinks it’s highly unlikely that the rover dug into a site where an ancient meteorite fell. She also notes that the signal was found at the base of an ancient lake, a potential catchment for life’s remains. “I suspect it’s geological. I hope it’s biological,” she says.

It must be emphasized once again that they have not found evidence of past life. What they have found are the types of molecules that are often left behind by life, but can also form without the presence of life.

This result, from past drillholes in the Murray Formation, explains however why Curiosity headed back downhill to do its most recent drill test.

Curiosity has one last tool to help the team find out: nine small cups containing a solvent that frees organic compounds bonded in rock, eliminating the need to break them apart—and potentially destroy them—at high temperatures. In December 2016, rover scientists were finally prepared to use one of the cups, but just then the mechanism to extend the rover’s drill stopped working reliably. The rover began exploring an iron-rich ridge, leaving the mudstone behind. In April, after engineers found a way to fix the drill problem, the team made the rare call to go backward, driving back down the ridge to the mudstone to drill its first sample in a year and half. If the oven and mass spectrometer reveal signs of organics in the sample, the team is likely to use a cup. “It’s getting so close I can taste it,” says Ashwin Vasavada, Curiosity’s project scientist at the Jet Propulsion Laboratory in Pasadena, California.

The newest drillhole sample has now entered the mass spectrometer. Stay tuned!

In order to bypass a failed feed mechanism in the rover’s drill, Curiosity’s engineering team has declared successful the new techniques they have developed for drilling and getting samples.

They had successfully completed a new drill hole two weeks ago, but are only now are satisfied that the new method for depositing samples in the laboratories will work.

This delivery method had already been successfully tested at JPL. But that’s here on Earth; on Mars, the thin, dry atmosphere provides very different conditions for powder falling out of the drill. “On Mars we have to try and estimate visually whether this is working, just by looking at images of how much powder falls out,” said John Michael Moorokian of JPL, the engineer who led development of the new sample delivery method. “We’re talking about as little as half a baby aspirin worth of sample.”

Too little powder, and the laboratories can’t provide accurate analyses. Too much, and it could overfill the instruments, clogging parts or contaminating future measurements. A successful test of the delivery method on May 22 led to even further improvements in the delivery technique.

Part of the challenge is that Curiosity’s drill is now permanently extended. That new configuration no longer gives it access to a special device that sieves and portions drilled samples in precise amounts. That device, called the Collection and Handling for In-Situ Martian Rock Analysis (CHIMRA), played an important role in delivering measured portions of sample to the laboratories inside the rover.

I suspect that they still need to do more tests, and that the new method of shaking off material from the drill itself will not always work. At the same time, it reopens the option of using the drill and getting samples from it, which is a very good thing.

For the first time in more than a year, Curiosity has successfully used its drill to obtain a sample from beneath the surface of Mars.

Curiosity tested percussive drilling this past weekend, penetrating about 2 inches (50 millimeters) into a target called “Duluth.”

NASA’s Jet Propulsion Laboratory in Pasadena, California, has been testing this drilling technique since a mechanical problem took Curiosity’s drill offline in December of 2016. This technique, called Feed Extended Drilling, keeps the drill’s bit extended out past two stabilizer posts that were originally used to steady the drill against Martian rocks. It lets Curiosity drill using the force of its robotic arm, a little more like the way a human would drill into a wall at home.

I plan to post a rover update either today or tomorrow, with more details about this success. Stay tuned!