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Planetary News: Phoenix (2008)Phoenix Ready to Rock Robotic ArmBy A.J.S. Rayl
PASADENA -- After a flawless landing Sunday and a healthy first sol on Mars, Phoenix is ready to rock its robotic arm and get on with collecting samples of icy arctic terrain to analyze with its instruments. It's just waiting for its agenda. The Phoenix team sent commands to the Mars Reconnaissance Orbiter (MRO) for relay to their spacecraft, instructing it to move its arm this morning, May 27. It was to have first unlatched its wrist, flexed its elbow, then moved the arm upwards in a stair-step manner. MRO, however, did not relay those commands to the lander, Fuk Li, manager of the Mars Exploration Program at NASA's Jet Propulsion Laboratory (JPL), said during a press conference at JPL this morning. "A transient event occurred on the UHF radio on the Mars Reconnaissance Orbiter and when this transient event occurred MRO is programmed to turn that radio off," Li said. "This occurred sometime this morning and because of that transient event those uplinks [to Phoenix] were not accomplished." Phoenix, meanwhile, is "healthy," Li said, and "resting peacefully on Mars." Barry Goldstein, Phoenix project manager, he noted was resting, ostensibly peacefully, at home, "after not having been home in a few days." Since Phoenix didn't get its To-Do List this morning, it ran out a sequence of preprogrammed commands installed especially for situations just like this. The navigation team at JPL has zeroed in on Phoenix, pinpointing it on the surface 22 kilometers downrange for the pre-E-D-L [entry, descent, and landing] estimate," Brian Portock, the navigation team chief announced. "We really landed in a spot the scientists were looking for," said Portock. Moving the arm remains Phoenix's next mission milestone. That checkout, along with other activities, are now planned for tomorrow, Wednesday, May 28.
While MRO's communication-relay system was in a standby mode, the MRO team was troubleshooting the anomaly with the UHF radio. At the time of the press conference, the Phoenix team was on stand-by. Depending on what happens with MRO's UHF radio, Odyssey orbiter is available for relaying communications between Earth and Phoenix, Li said. If the MRO radio isn't up and working by tomorrow morning, Odyssey will uplink Phoenix's marching orders. It's just an annoying glitch, it appears. On the plus side -- two thumbs way up -- MRO did send back spectacular first images of the landed Phoenix from orbit, views of the lander and the area where it will work for the next three months, all taken by the High Resolution Imaging Science Experiment (HiRISE) telescopic camera, headed by Alfred McEwen of the University of Arizona, and a preliminary weather report, from the MARCI instrument, run by Michael Malin, of Malin Space Science Systems. McEwen and Phoenix Principal Investigator Peter Smith joined the press conference from the University of Arizona Phoenix Science Operations Center, at the University of Arizona, via video link. One of the newly processed images from HiRISE shows a full-resolution view of the Phoenix parachute and lander during its May 25 descent, with Heimdall crater in the background. "It's the same image Barry [Goldstein, Phoenix project manager] showed yesterday only in our exuberance to see the parachute we just zoomed in on the parachute," said McEwen. "Later we zoomed out and were astonished to see the setting of this crater behind Phoenix as it's descending on its parachute. It looks like Phoenix is dropping into the steep, rocky slope of this 10-kilometer (6-mile) crater. But it's not," he said.
Phoenix is actually 20 kilometers, (about 12 miles) in front of the crater. "It's an optical illusion that's hard to understand, because we're looking through a very large focal length telescope," McEwen said. "But this really gives you an idea of how small Phoenix is." The HiRISE team has done "some improved processing" of the parachute image" McEwen added, in which you can actually see the orange and white strips of the paachute and the strings that attach it to the backshell. HiRISE also turned its lens to Phoenix on the ground. "And thanks to Brian [Portock, of JPL, the navigation team chief] and others and their work in locating it we were able to hit Phoenix on the ground in our first two tries," McEwen said. The first one is 11 hours after E-D-L and the next one was 22 hours later. The second one HiRISE captured in color. "The image just came in late last night an Eric Eliason and others at our operations center in the wee hours of the morning were processing that image to have it ready for us this morning," he noted. The image shows the parachute attached to the back shell, the heat shield and the lander itself against red Mars. The parachute and lander are about 300 meters (around 1,000 feet) apart. "There it is," said McEwen. "It stands out remarkably well against the backdrop of Mars." Commands to be sent to the lander Wednesday morning instructing Phoenix to make the first movements of the mission's crucial robotic arm also include taking more pictures of the surroundings.
The biobarrier, a covering that had shielded the arm from microbes during its last few months before launch had not fully retracted on landing day, May 25, but it moved farther from the arm on Monday. "The biobarrier has relaxed more and allows more clearance, but it was not a major concern either way," said Li. During the next three months, the arm will dig into soil near the lander and deliver samples of soil and ice to laboratory instruments on the lander deck. Phoenix principal investigator Peter Smith of the University of Arizona was delighted with new images of the workspace. "We were so pleased last night to get some more images around our landing site. This is the first of a series of mosaics that will take us all 360-degrees around the lander, but first we're looking to the south. As we look into the terrain we see a sparsely rock surface and we see the mounds and the troughs that present the polar terrain on mars and we can zoom into the distance we can see the backshell and the parachute. Though we can't see much detail. We'll take a high-resolution picture later on. You can also see some hills about 9 miles away. And we can see it clearly – that means there's not much dust in the atmosphere." The workspace is, Smith said, "ideal" because "it looks very digable." We're very happy to see just a few rocks scattered in the digging area, which is great news to me, because the arm is not built really to handle a very rocky terrain, so we have lots of areas we can dig in." This is a place we're going to get to know very well over the next three months. We are fairly sure –both from Alfred's picture and from some preliminary elevation maps we'll be able to get into one of the troughs and that has the science team quite excited -- to look at the difference of the underlying surface and ice in the trough area and then in the middle of one of the polygons we've seen. The Phoenix weather station, provided by the Canadian Space Agency, was activated within the first hour after landing on Mars, and measurements are now being recorded continuously. The data from the first 18 hours after landing have been transmitted back to the science team, and Smith offered up the first real weather report from Mars.
The temperature ranged between a minimum of -80 degrees Celsius (-112 degrees Fahrenheit) in the early morning and a maximum of -30 degrees Celsius (-22 degrees Fahrenheit) in the afternoon. The average pressure was 8.55 millibars, less than a hundredth of the sea level pressure on Earth. "And the wind speed was 20 kilometers per hour (13 miles per hour), out of the northeast. The skies are clear," he said. More instruments will be activated in the coming days, and the weather report will expand to include measurements of humidity and visibility. "We'll be having weather reports throughout the mission," Smith said. Smith also presented a new Surface Stereo Imager view released yesterday of the American flag and a silica glass mini-DVD on the Phoenix's deck, about three feet above the Martian surface. "It's our Memorial Weekend Day picture," said Smith. The mini-DVD, Visions of Mars, from The Planetary Society, contains a message to future Martian explorers, science fiction stories and art inspired by the Red Planet, and the names of more than one quarter million Earthlings. "This DVD will be there for a very long period of time. On the label, it says: "Astronauts please take this with you.' Someday somebody will come and take that DVD and be able to read the books in our little library," he said. "We proud to be making such progress," Smith said in concluding remarks. "It's only been a day and a half since we landed. We're already getting a good sense of the space around our lander. We've got wonderful pictures from Alfred's Hi-RISE telescope. Brian Portock has located us on the surface with his navigation. And we're really feeling very positive about this mission and can't wait to start interacting with the soil and doing our scientific investigations." For full resolution of images, go to: http://phoenix.lpl.arizona.edu/ and http://hirise.lpl.arizona.edu. The Phoenix mission is led by Smith at the University of Arizona with project management at JPL and development partnership at Lockheed Martin. International contributions come from the Canadian Space Agency; the University of Neuchatel, Switzerland; the universities of Copenhagen and Aarhus, Denmark; Max Planck Institute, Germany; and the Finnish Meteorological Institute. General Timeline for Phoenix Mission OperationsEvent times are given in Spacecraft Event Time
(SCET), which is the time according to the spacecraft's clock, and also
Earth Received Time (ERT), which accounts for the 15 minutes and 20 seconds
it takes radio signals to traverse the 275 million kilometers (171 million
miles) separating Earth and Mars on landing day. ERT is given both in Universal
Time (UTC) and Pacific Daylight Time (PDT).
The first week following landing will be a "characterization phase," during which the instruments and systems will be ckecked out and tested. Approximately one week after landing, the digging phase will begin, and the first sample of surface soil will be delivered to the Thermal and Evolved-Gas Analyzer (TEGA) instrument. The first analyses will take 10 to 15 days. At the same time as the instruments are being checked out, a parallel effort will be undertaken to determine exactly where Phoenix landed. An approximate location will be known within hours of landing, and two Mars Reconnaissance Orbiter HiRISE images will be taken. However, the knowledge of the location of Phoenix may not be good enough to steer the targeting of HiRISE on the first day. Another imaging attempt planned for the fifth day is more likely to be successful. Digging will proceed in several cycles lasting 8 to 15 days apiece. After each two to three centimeters of digging, new samples will be delivered to TEGA and to the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA). The nominal mission plan accounts for a total of seven cycles of digging and analysis. It is unknown how far Phoenix will have to dig to reach ice, but it is epected to be about two to five centimeters. If the ice is found at the deeper end of the range, the first ice samples may not be analyzed until July or later. The digging phase is expected to last until the beginning of September, 90 sols after landing. Once the digging phase is over, Phoenix will continue to operate essentially as a polar weather station. The mission will end when the Sun travels low enough in the sky that Phoenix no longer receives sufficient power. The spacecraft will conserve power as long as possible. The cameras will search for the first carbon dioxide frost deposits while the Meteorological Station (MET) instrument monitors the weather conditions. The northern autumnal equinox will arrive on Mars on December 26, 2008, bringing winter darkness to the north pole. Phoenix will not survive past this date. In fact, it may not survive beyond November. Emily Lakdawalla contributed this Timeline to this report. For the Phoenix Mars Mission home page, go to: http://phoenix.lpl.arizona.edu/ NASA TV will cover the Phoenix landing events. For information on how to connect: http://www.nasa.gov/multimedia/nasatv/index.html
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