 |
 |
||
 |
|
||
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
||||||||
 |
Planetary News: Phoenix (2008)Analysis of Phoenix’s First Official Study Sample to BeginBy A.J.S. Rayl
TUCSON -- Phoenix has scooped up its first official sample and brought it back to the deck for scientific analysis. The data confirming that it had captured its prey came down to the University of Arizona Science Operations Center late Thursday night where it was greeted with cheers and applause. "Last night we verified we captured a sample. It looks like a good sample for us," Peter Smith, Phoenix principal investigator, of the University of Arizona, announced Friday morning during a press conference. The scoop, filled with about one cup’s worth of the clumpy reddish-brown Martian soil, was positioned over an open door on the Thermal and Evolved-Gas Analyzer – better known simply as TEGA – which will bake and sniff the soil to assess its volatile ingredients, such as water. Today, Phoenix received commands to dump the soil sample into that open door, which leads to oven #4. Confirmation of the dump – expected early Saturday morning -- will signal the end of the characterization and checkout phase and the beginning of the science mission, Smith said. “This is really an important occasion for us. Over the next few days, maybe as much as a week, the TEGA instrument will be analyzing this sample,” he said. TEGA is a highly sophisticated, complex instrument that features eight tiny, but extremely powerful ovens about the size of the lead in your pencil. The team chose to use oven #4 first, because “it’s the thermal analyzer with which the robotic arm team had the most practice in the pit,” according to the University of Arizona’s William Boynton, the principal investigator of the instrument. “It is also easier for the robotic arm camera to view this side,” he added. “Once we got the sample, we lifted up and swung the arm around and positioned scoop above TEGA,” said Matt Robinson, the robotic arm flight software lead, of NASA's Jet Propulsion Laboratory (JPL). The move was calculated to get enough material to ensure delivery into the instrument without inundating it with unnecessary extra soil. “We were aiming [to fill the scoop] one-quarter to one-third of the way and we got exactly what we wanted. We’re ecstatic. We couldn’t be more happy," he said. Although the team won’t know until Saturday morning if Phoenix performed the dump as planned, no one has any reason to believe it won’t perform the drop exactly as commanded.
From the image returned late last night, however, it looks like Phoenix might be even more anxious that its ground team to get on with the science phase of the mission – and may have already dropped a bit of the sample into the oven. Phoenix collected the Martian material from the top 2 to 4 centimeters (0.8 to 1.6 inches) of surface material at a site dubbed Baby Bear. This sample area is just to the north side of the lander and right next to where the lander conducted its two practice dig-and-dumps earlier this week. In those tests, Phoenix followed its instructions and dumped the soil back onto the surface out of the way of the still pristine Humpty Dumpty National Park. That’s where the spacecraft will soon be looking for a layer of ice that the Mars Odyssey orbiter revealed in 2001 was there, just under the surface. Phoenix’s rise from the “ashes” of Mars Surveyor 2001 -- which was cancelled after the failures of Mars Climate Orbiter and Mars Polar Lander in 1999 -- is the stuff of legends and fairy tales. Appropriately, it seems, the team members decided to name targets and locations at the site after fairy tales and legends. For five years, the robotic arm team practiced with simulations and equipment on Earth, knowing that practice, as the adage goes, makes perfect. "It's like being on a football team and having a pre-season that lasted five years,” said Robinson. Now we're finally playing our first game” -- and, with only two practices at “the stadium” where the big show is being staged.
The TEGA instrument will begin analyzing the snared sample for water and mineral content once it has examined a sample of the Martian atmosphere, also slated for Phoenix’s agenda Friday. The team is "particularly interested” in minerals that are formed or altered by the action of liquid water in the soil, Smith said, and whether it might be water that is “cementing” the Martian particles into the reddish-brown clumps that seem ubiquitous in the region where Phoenix set down. While science team members are not expecting to find liquid water in this particular sample, the stuff of life as we know it can be bound to minerals, such as clays or carbonates. TEGA can identify those and other minerals by virtue of heat, on the basis that it takes varying amounts of heat to drive the water off minerals. Several sols ago, when the lander was testing its dig-and-dump procedures, it accidentally dropped a bit of this clumpy Martian soil onto the silica glass Visions of Mars DVD, provided by The Planetary Society. While that may seem at first blush to be not such a good thing, in fact, science team members have been keeping a close eye on that dropping and reported Thursday night at a science team meeting that nothing has changed from Sol 8. That likely means there is no Martian ice in that sample for if there were the clumps would have gotten smaller or changed in appearance. It also means, noted Smith between tactical operations and science meetings last night, that “The Planetary Society is contributing to the science of this mission.”
Phoenix has experienced a couple of communications glitches since landing on May 25, during the Memorial Day weekend, but those events have turned out to be minor and the issues appear to be fully resolved. The team initially used the Electra radio on the Mars Reconnaissance Orbiter (MRO), but on the second day of the mission that radio intermittently began turning itself off, so the team turned to Odyssey so the MRO Electra team could figure out what was going on. Then, last Wednesday, Odyssey went into safe mode, just a few days after MRO’s radio team restored the Electra, so the Phoenix team returned to using the MRO radio to uplink commands and receive its data downlinks Since Phoenix did not receive its marching orders for the day, the lander completed a back-up plan of activities that had been previously programmed into the spacecraft’s flight software, previously, reported JPL's Chris Lewicki, mission manager for Phoenix surface operations. That plan included weather monitoring and additional imaging for a high-resolution color panorama of the site. As it turns out, Odyssey suffered “a single event that affected computer memory," according to Chad Edwards chief telecommunications engineer for the JPL Mars Exploration Program, an event that appears to be very similar to events that have caused the orbiter to go into safe mode several times before during its six and a half years at Mars. "We are currently bringing Odyssey back into nominal operations,” said Edwards Thursday. And today, the team resumed relay service with Odyssey and now will continue to primarily rely on that NASA orbiter.
Phoenix can and will, however, also use MRO’s Electra radio from time to time, Edwards said. MRO and Odyssey offer the Phoenix team different windows of time to uplink commands and downlink data, hence, the capability of using either one offers the mission much greater flexibility. In the event of an emergency, the team can also reach their bird via the European Space Agency’s radio onboard Mars Express. The mission has also succeeded in sending home the highest resolution picture ever taken on Mars, an image of dust and sand particles that had fallen onto a silicone filled dish during landing and in the week following. The picture, which was imaged with Phoenix’s optical microscope, a part of the Microscopy, Electrochemistry and Conductivity Analyzer (MECA) instrument suite, revealed grains as small as one-tenth the diameter of a human hair. Even more importantly, the image indicated that the Martian arctic surface may be much more varied than scientists initially thought. "These images show the diversity of mineralogy on Mars at a scale that is unprecedented in planetary exploration," said JPL’s Michael Hecht, lead scientist for MECA. "It's a first quick look," Hecht added. "This experiment was partly an insurance policy for something to observe with the microscope before getting a soil sample delivered by the arm, and partly a characterization of the optical microscope,” he explained. Everything, he added, is working well.
Some of the particles might have come from inside the spacecraft during the forceful events of landing, but many match expectations for Martian particles. "We will be using future observations of soil samples delivered by the robotic arm to confirm whether the types of particles in this dustfall sample are also seen in samples we can be certain are Martian in origin," Hecht said. The particles show a range of shapes and colors. "You can see the amount of variety there is in what appears otherwise to be just reddish brown soil," said Tom Pike, Phoenix science team member, of Imperial College London. He noted that one translucent particle resembles a grain of salt, but that it is too early to say for sure. If Tucson’s triple digit temperatures are hot, Phoenix is even hotter. Since landing, the mission has commanded headlines and news broadcasts around the world. The University of Arizona -- which is the first public university to lead a NASA mission -- has “streamed up” videos and animations, ranging from one minute to 50 minutes, onto iTunes U, the education-focused portal hosted by Apple’s iTunes. Since then, Phoenix has flown around the top of the most downloaded videos list. In Tucson, meanwhile, merchants and shopkeepers are hanging signs and billboards around their desert town celebrating their world-renowned bird. Phoenix is the first NASA Scout mission, designed to complement the large missions to Mars. Project management is being handled by JPL, with a development partnership at Lockheed Martin, Denver. For more information:
|
|||||||||||
 |
 |
|||||||||||
[ what is this? ]