Saturday, June 14, 2008

The Week On Mars

Image credit: NASA Phoenix Mission. The caption reads: This image shows NASA’s Phoenix Mars Lander’s solar panel and the lander’s Robotic Arm with a sample in the scoop. The image was taken by the lander’s Surface Stereo Imager looking west during Phoenix’s Sol 16 (June 10, 2008), or the 16th Martian day after landing. The image was taken just before the sample was delivered to the Optical Microscope. Click on the link to be taken to NASA's page about the image, which links to a full-sized version suitable for wallpaper.

It was a good week, although it didn't start out too well:

Dirt that the Phoenix Mars Lander scooped recently from the planet's surface may be too clumpy to be analyzed by the machine's onboard system, NASA reported on Saturday.

A robotic arm retrieved a cup-sized sample of Martian dirt on Friday and placed it on the lander's Thermal and Evolved-Gas Analyzer, or TEGA, which was scheduled to spend about a week determining the soil's water and mineral content.

The TEGA features a screened opening that prevents large particles from clogging it. Only those thinner than 1 mm (0.04 of an inch) can pass through, and an infrared beam verifies whether they have entered the instrument.

The beam has not yet confirmed any activity and researchers are not sure why, NASA said in a statement.

Mars lander's 1st soil sample may not be analyzed

The problem turned out to be something that even the most inexperienced gardeners would be familiar with:

Images taken on Friday show soil resting on the screen over an open sample-delivery door of TEGA, which is designed to heat up soil samples and analyze the vapors they give off to determine the soil's composition.

The researchers have not yet determined why none of the sample appears to have gotten past the screen, but they have begun proposing possibilities.

"I think it's the cloddiness of the soil and not having enough fine granular material," said Ray Arvidson of Washington University in St. Louis, the digging czar for the $420 million Phoenix mission.

Martian Soil Sample Clogs Phoenix Probe's Oven

Apparently, NASA has at least a few gardeners on its tech teams. It had put the TEGA oven entrance on a vibrator, which finally succeeded in breaking up the clumps:

After days of struggling with sticky Martian dirt, the Phoenix Mars Lander has unexpectedly succeeded in getting its first soil sample into an onboard laboratory for analysis, jubilant NASA scientists said on Wednesday.

The breakthrough came after the lander spent days vibrating a screen over its onboard Thermal Evolved Gas Analyzer (TEGA) in hopes that the clumpy soil would break loose and fall into the onboard ovens. The scientists were caught by surprise when the trick worked on the seventh, and likely last, try.

Martian soil falls into Phoenix oven at last

So, by Wednesday they were baking that dirt. According to that New Scientist article, it will take a week to analyze the data. That means we'll probably be hearing something by this Thursday, maybe sooner.

Meanwhile, they put some other dirt under a microscope yesterday:

Images from Phoenix's Optical Microscope show nearly 1,000 separate soil particles, down to sizes smaller than one-tenth the diameter of a human hair. At least four distinct minerals are seen.

"It's been more than 11 years since we had the idea to send a microscope to Mars and I'm absolutely gobsmacked that we're now looking at the soil of Mars at a resolution that has never been seen before," said Tom Pike of Imperial College London. He is a Phoenix co-investigator working on the lander's Microscopy, Electrochemistry and Conductivity Analyzer.

The sample includes some larger, black, glassy particles as well as smaller reddish ones. "We may be looking at a history of the soil," said Pike. "It appears that original particles of volcanic glass have weathered down to smaller particles with higher concentration of iron."

NASA's Phoenix Mars Lander Delivers Soil Sample to Microscope

Why study all this Martian dirt? One of the reasons is to better understand what's happening on our own planet, and why:

The fine particles in the soil sample closely resemble particles of airborne dust examined earlier by the microscope.

Atmospheric dust at the Phoenix site has remained about the same day-to-day so far, said Phoenix co-investigator and atmospheric scientist Nilton Renno of the University of Michigan, Ann Arbor.

"We've seen no major dust clouds at the landing site during the mission so far," Renno said. "That's not a surprise because we landed when dust activity is at a minimum. But we expect to see big dust storms at the end of the mission. Some of us will be very excited to see some of those dust storms reach the lander."

Studying dust on Mars helps scientists understand atmospheric dust on Earth, which is important because dust is a significant factor in global climate change.

"We've learned there is well-mixed dust in the Martian atmosphere, much more mixed than on Earth, and that's a surprise," Renno said. Rather than particles settling into dust layers, strong turbulence mixes them uniformly from the surface to a few kilometers above the surface.

NASA's Phoenix Mars Lander Delivers Soil Sample to Microscope

So far, we're only familiar with how things work on one planet with an atmosphere. To have a better understanding of how the peculiarities of our atmosphere affect its behavior, studying another is essential. It's also essential if we want to understand how changes in our atmosphere will affect other things. The same is true of geology.

While this group of NASA people were playing in the dirt, another was bringing the shuttle back to earth:

Space shuttle Discovery and its crew of seven returned to Earth on Saturday and capped a successful expansion job at the international space station, more spacious and robust thanks to a new billion-dollar science lab.

Shuttle returns to Earth after 14-day mission

That new science lab is the Kibo, Japan's science laboratory. Here it is in a NASA photo from last week. The full size version is here. Speaking of gardens, it will eventually have its own box garden on its own porch:

The Exposed Facility, or EF, is a unique platform on the ISS that is located outside of the Pressurized Module and is continuously exposed to the space environment. Astronauts exchange experiment payloads or hardware from the Pressurized Module through the scientific airlock using the Kibo Remote Manipulator System. Items positioned on the exterior platform focus on Earth observation as well as communication, scientific, engineering and materials science experiments.

The EF is a platform that can hold up to 10 experiment payloads at a time and measures 5.6 meters (18.4 feet) wide, 5 meters (16.4 feet) high and 4 meters (13.1 feet) long.

NASA Page: Kibo Japanese Experiment Module

That section will be brought up in a later shuttle flight.

On the whole it was a very successful week.


Dana Hunter said...

Exciting stuff! Cracks me up that no one seems to have really anticipated that Martian soil may be clumped - I mean, come on, people, it's dirt! Dirt does that. Haven't they ever seen a desert before? Scientists: so smart they can't think sometimes. ;-)

At least they figured out a way around it, and we should get some very intriguing data soon.

Cujo359 said...

Hi Dana,

Yes, it makes me wonder whose idea it was to put that vibrator on there. It certainly wasn't done by accident - every gram counts when you're launching something into space. They don't just put stuff on a probe unless they think it will be useful somehow. Yet some folks seem genuinely mystified that the stuff is clumped.