Mars' Sticky Soil Strikes Again
Written by Nancy Atkinson
Phoenix's scoop hovers over TEGA. Credit: NASA/JPL/Uof Arizona
NASA's Phoenix Mars Lander scraped up some icy soil with its robotic arm and scoop and then attempted to quickly deliver the sample to the oven on board. But not enough soil made it to the oven; the icy soil stuck to the scoop. Engineers determined the rasping and scraping activity collected a total of 3 cubic centimeters of icy soil, more than enough to fill the tiny oven cell of the Thermal and Evolved-Gas Analyzer, or TEGA. However, images returned from the lander Saturday showed that much of the soil remained lodged in the robotic arm's scoop after the delivery attempt. "Very little of the icy sample made it into the oven,†said Barry Goldstein, Phoenix project manager. “We believe that the material that was intended for the targeted cell is the material that adhered to the back of the scoop.â€
Once the sample had been collected, the robotic arm tilted its scoop and ran the rasp motor several times in an attempt to sprinkle the sample into the oven whose doors were wide open. The scoop was then inverted directly over the doors. A screened opening over the oven measures about 10 centimeters (4 inches) long by 3 centimeters (1.5 inches) wide. The oven itself is roughly the size of an ink cartridge in a ballpoint pen.
But TEGA's sensors didn't detect enough soil in the oven for the oven doors to close. Commands were also sent to vibrate the screen on TEGA several times. The good news there is that the vibrating did not cause the oven to short circuit, a problem that occurred earlier and engineers have been worried that vibrating could possibly short out the entire instrument. But TEGA lives on for the team to try again to quickly deliver the icy soil to the oven before the ice sublimates away in Mars thin atmosphere. The ice can exist just under Mars surface, protected by the soil.
Goldstein said the team will adjust their sample drop-off strategy and try again.
Original News Source: Phoenix News
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July 27th, 2008 at 6:53 am
This must be frustrating as hell for the people running the mission.
July 27th, 2008 at 7:48 am
Those martian microbes are really fighting hard to avoid being cooked in TEGA.
July 27th, 2008 at 10:14 am
I think they should've put some machine to scratch the arm and get the dirt in there. Everyday, we're knowing the growing necessity of a real live human to lead a mission like this.
Face it, machines suck. I'm sure we'd be waiting for at least a century for a "Matrix" like phenomenon to happen.
July 27th, 2008 at 3:05 pm
Machines are wonderful things, but nothing gets it done like boots on the ground.
July 27th, 2008 at 8:35 pm
Hands up those who expect Phoenix to short out on the same day as they actually deliver some wet soil into the oven …
But seriously, this would have to be one of the low points of this entire mission, the landing was great, but lets face it, going back to something you used to be able to do isn't / shouldn't be that big a deal .. this is the money maker, and quite frankly, poor planning, lack of vision and poor design could lead to reduced funding for future missions as well as miss an ideal opportunity to excite the world .. such a shame, or am i being too hard ?
Cheers,
al.
July 28th, 2008 at 12:51 am
Would it not have been possible to build some kind of a "core sampling" device that drilled into the ground and then retracted back into the lander there delivering the sample into an exact position? Like we do here on Earth but obviously on a much smaller scale… Taking a core sample would alleviate the need to have to do it quickly as it would be protected by casing. It just seems to me that they put way too much functionality (and of course mass) into the robotic arm but for all of these bells and whistles they can't get the basic work done!? How about a smaller arm and bigger ovens? Granted I do not know all of the considerations involved but it's a long trip and a big investment only to show up with a system that has so many potential variables that could thwart it's success!?
Dribbling samples from above through the Martian air (What about Wind?) into tiny little ovens sure seems a good way for a lot to go wrong…
Just bummed out and frustrated I guess, as no doubt the NASA folks are as well… It's easy to be critical which isn't my intention. I've yet to build any spaceships myself so I guess until I do I should be happy I even get to watch! This is the most exciting thing we've got going on as a planet IMHO and considering the budget they have to work with I think it's pretty amazing we're there at all… How about… Less Bombs… More Spaceships! Sorry for the rant. 
July 28th, 2008 at 1:57 am
Seems Teflon has been forgotten.
July 28th, 2008 at 4:33 am
This Pheonix project just isn't grabbing my attention the way other Mars missions have done.
I think it's too techincal for me to understand the nitty gritty of it and there arent any pretty pictures.
I'm sure it's me being dim and the science is stunning for scientists but for common people like me it's just not exciting.
What does everyone else think ?
July 28th, 2008 at 6:10 am
I've been begging for the true color pictures. The Phoenix website finally posted a FAQ to address the issue. One of the early "approximate color" pictures had a small greenish area on a rock near to Phoenix – there is a possibility that some form of microbe grows just under the surface or in the pores of some rocks. An astronomer named Earl Slipher observed a Texas-sized region on Mars in 1954 turn from the desert orange color to a grey-green. It was widely observed and reported. His observations, combined with Sinton's spectral observations of organic bonds in the dark areas suggests that life – at least very hardy microbes – might be present in the dark areas. So I keep begging for the true color pictures – hopefully we'll get them soon. I'd love to revise our book "Imminent Discovery" with the actual discovery of life on Mars.
July 28th, 2008 at 8:54 am
I am very suspicious about the subliming ice and am still waiting for some analytical data. CO2 sublimes nicely and looks just like water ice. Isn't the Martian polar ice cap mostly CO2? Hopefully the rate of sublimation is not the only evidence for water on Mars!
July 28th, 2008 at 3:43 pm
First of all, I'm by no means a scientist.
But isn't the obvious being overlooked? That being WHY did the soil STICK to the scoop?
By my low impact, low intelligent mind, that says the soil is MOIST….with what?
Perhaps that answer will come soon.
July 29th, 2008 at 5:21 am
Think ice cream scoop – the ice cream only startssticking to metallic ice cream scoops as the temperature of the scoop gets closer to that of the ice cream – raising the temperature of the ice cream scoop solves the problem – this problem, on a mission of this magnitude just suggests sloppy engineering, or, engineers who have never had to scoop out their own ice cream – do engineers eat ice cream?
David from AS-SP
July 29th, 2008 at 6:55 am
I like the idea to create a bigger temperature difference between the scoop and the sample. And, I would assume this is something that can be attempted, either by holding the scoop in the sun during the warmest time of the day and then picking up a sample that's still in the shadow of the lander. or by warming up the scoop near some part of the lander where the heaters are located.
Other then that… one wonders why the scoop doesn't have a backplate that can push the samples over the edge of the scoop, into the ovens.
Another option is to bump the scoop into the oven, the force of the shock might make the sample fall in and the robotics is probably accurate enough to do this after some testing with the model on earth.
Good luck!