From the editors: Mars Phoenix scientists have finally confirmed finding ice at the landing site (watch the chunks sublimating in the lower left of the trench in the animated image below). Read our full story here. And for more on a new study about how volcanism and ice may have shaped Mars’s northern regions, try this news story.
The Phoenix mission scientists just won’t call it ice. It’s getting almost hilarious the way they assiduously avoid the term. On a conference call today, Ray Arvidson, the robotic arm lead scientist, talked about some of the features of a deep 5 to 7 centimeter trench. The trench combines “Goldilocks” and “Dodo” — two shallower test trenches. You can see the ledge of exposed “light-toned” (as they call it) material in the upper part of the trench. You can also see a little tiny nugget of something — don’t say that word — sitting just to the left of center in the trench.
So the team is going to watch what happens to these two features over time. The chunk, being small and exposed, would be expected to sublime and disappear over time. And the ledge, if it was an extension of the cold, thick ice table below, might actually be expected to accumulate frost. We’ll see.
Bill Boyton, lede for the TEGA instrument, said the baking is going well — they’ve performed two step-wise bakes, up to 175 degrees Celsius, without detecting anything other than carbon dioxide. In the next few days, he’ll amp that oven up to 1000 degrees Celsius. That’s when things will really start cooking.
After five days of shaking, TEGA will finally get around to some baking. Last Friday, the robotic arm dropped some soil onto the screen door of one of the ovens for TEGA, Phoenix’s main chemical analysis instrument. But the soil was apparently too clumpy. Mission scientists sent commands to vibrate the instrument, which resulted in some material getting through the screen (see the animated gif here). But somehow it wasn’t getting into the oven. Today, something finally gave — was it the weather? was it the vibrating? — and the oven is now full. Now they’ve got to worry about contamination.
For future TEGA tests, the team is experimenting with a new “sprinkle” test. Instead of burying the TEGA door in one big dump, the team may angle the scoop, and then run the ice rasp at its back – vibrating the scoop enough to send a fine stream of soil particles over the edge.
Is Phoenix, and one of its premier instruments, TEGA, covered in too much microscopic crud from Earth to detect Martian organics? That’s the question I try to explore in my latest story on the main Nature news site. TEGA, pictured on the right, is about to begin baking soil samples and sniffing the gases that come off it in the hopes of detecting organic molecules. But whether the TEGA team can say anything definitive will depend on how free the instrument is of Earth organics. Yesterday, Phoenix had its scoop poised at the edge of one of TEGA’s eight oven doors, and today, it was going to let the soil dribble through TEGA’s sieve.
New Scientist reporter (and former Nature intern) Ewen Callaway has an excellent story on a related issue: Are Earth microbes so hardy that they could survive on Mars? A JPL microbiologist found a lot more bugs than you might think living in supposedly clean assembly rooms. And while great care was taken with the robotic arm, wrapping it in a biological barrier, there are other parts of the spacecraft that were not kept as clean. What about the lander feet? They don’t interact with the soil as much as the robotic arm, but they could easily have landed directly on ice. Is an antiseptic wipe down before launch enough?
Yesterday, Mars Odyssey failed to send Phoenix instructions for the day — and so engineers have switched back to Mars Reconnaissance Orbiter as the go-to relay link.
This is the second time that Phoenix has lost a day due to a balky communications link. When it happens, Phoenix still stays reasonably busy, following “run-out” instructions that tell it to take panoramic pictures. But it isn’ t what the scientists want to be doing. Yestersol (sorry, hooked on the term), Phoenix was supposed to move its first soil sample to the edge of TEGA’s maw. That’s going to happen today, assuming the MRO uplink works. Tomorrow Phoenix will tilt the scoop and drop the soil in. And so on, day by day.
The team is prepared for the slow work — even budgeting for down days like yestersol. JPL flight systems engineer Chris Lewicki says that the team should accomplish all its science goals even if 30 of the mission’s 90 days are lost to the unforseen.
The press conference focused on some of the first optical microscope pictures in MECA. Some really cool images of three grains, likely kicked up during the landing, can be found here. MECA lead scientist Michael Hecht said these pictures had 10 times better resolution than microscopic pictures from the Mars rovers. That’s a nice superlative: The tiniest things ever seen on Mars.
Also in this week’s Nature, we did something unusual: a “”https://www.nature.com/news/2008/080604/full/453712a.html">snapshot feature." Some of our editors were so taken by the photo of Phoenix descending in front of Heimdall crater that they carved out two full pages in our features section, usually reserved for longer, analytical stories.
If there’s ever a time to pilfer the copy of Nature from the departmental common room, then this week is it. Heck, I’d pay money for a nice glossy poster. The folks at Mars Reconnaissance Orbiter should seriously start selling prints of this — maybe they can pay for the cost overruns on Mars Science Laboratory.
I have a new story up on the main Nature News site about the mystery of the polygons on Mars, which are analogous to the polygons found in the Arctic and Antarctic on Earth. Mike Mellon thought he had them all figured out — he had a model that perfectly explained the five meter polygons he was seeing from Mars Reconnaissance Orbiter’s HiRise camera (pictured here). Then Phoenix landed and they were too small. Strangely, Mellon also sees the faint imprint of really large polygons, maybe more than 20 meters across. One idea is that each polygon size reflects the freezing mechanics of a different climatic epoch. The most prominent polygons reflect the active climate, while the receding ones are the half-erased remnants of climates of yestersol (a Mars-mad neologism that I heard a JPL engineer use yesterday). The surface of Mars would therefore be a palimpsest (perhaps my favorite word in the English language).
No, that isn’t Phoenix PI Peter Smith. And that’s not the Surface Stereo Imager.
That’s a decade old picture of David Paige, PI for the doomed Mars Polar Lander, with the previous incarnation of the SSI.
On one of the recent Phoenix conference calls, a journalist asked — had anyone talked to Paige? Did he watch the landing? Good questions. I called him up — he’s a professor at the University of California at Los Angeles — and had a quick chat. Turns out he did watch the Phoenix landing from JPL, with his 5-year-old son.
First, the background. Mars Polar Lander was headed to the south pole to perform a similar mission as Phoenix, but was lost upon entry to the atmosphere in 1999. Its failure led to the cancellation and closeting of the parts that were going into the Mars Surveyor lander — and it was those parts that were resurrected to make Phoenix.
Paige recalled the tense moments of his landing operation, which also occurred at JPL. It was a low budget operation, and Polar Lander didn’t have direct telemetry to Earth during its descent. From the time it left the cruise stage, until it touched down and started beaming signals back to Earth 20 minutes later, mission managers had to wait in silence.
Paige recalled the silence persisting after 20 minutes. And persisting. That began weeks of fruitless searches for any signal that Polar Lander was alive. Its wreckage (though it might not have crashed) still hasn’t been found. Instead of seven minutes of terror, Paige had months of anxiety, followed by years of disappointment. “We’ll get closure eventually,” he says. “It’s like the lost relative that went on the hiking trip and never came back. And you never found the body.”
“We came very, very close to doing something unique. You can’t help but wonder what we might have discovered…” he says, trailing off.
But he’s not feeling bitter by the success of Phoenix. Bittersweet, maybe. It brings back difficult memories, but he’s not jealous. “They deserve success and so far it looks like they’re getting it.”
He also puts a positive spin on the failure of Polar Lander, saying it was necessary in order for Phoenix to succeed. The Phoenix team scoured the old Surveyor parts relentlessly, and identified and eliminated failure modes.
After several months of searching for Polar Lander, Paige sent an email to his team, saying it was time to call off the mission. Paige didn’t drop off the face of the Earth, but he did decide not to get involved with Phoenix. Five years down the drain was a lot, but not his whole career. He’s now a PI for a thermal mapping instrument on the upcoming Lunar Reconnaissance Orbiter. “There are always more chances. It’s not the end of the world,” he says. “No mission is the last mission to Mars.
Proof that life can survive on Mars.
Phoenix’s robotic arm has scooped up its first mouthful of Martian soil, mission scientists announced today. In a test “dig and dump” area to the west of the “National Parks” that are off limits for now, the robotic arm easily slid into the soil. The color picture here, taken with the LEDs of the robotic arm camera, gives a good sense of the crumbly, crusty overburden that the team will be digging through to get to the ice that they’re pretty sure lurks just below.
In fact, they might have reached it already. If you look really carefully at the picture, a quarter of the way from the right, you can see what appears to be filigrees of frost. Robotic arm lead Ray Arvidson, of Washington University in St. Louis, said the white stuff could also be a water-borne magnesium sulfate salt.
In other news, PI Peter Smith said that a back up filament — used to ionize the gases coming off baked soil samples — should work as well as the primary filament, which is suffering from an electrical short circuit. Smith said the team plans to dump their first soil samples into the one of the ovens either tomorrow or the next day.
Image: NASA/JPL/University of Arizona