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Planetary News: Phoenix (2008)Phoenix Glides into Fourth Day on MarsBy A.J.S. Rayl
TUCSON -- With a high of -22 degrees Fahrenheit and a low of -112 degrees, it’s sunny with some dust activity and moderate visibility on Mars and only Phoenix’s fourth day in the arctic region of Mars, but the “well-behaved” spacecraft is soaring into its mission. On Wednesday evening, the lander transmitted data that confirmed it had moved its 7.7-foot robotic arm out of its launch configuration, completed the first 360-degree panorama of its workspace, tested a laser instrument for studying dust and clouds, and delivered its second weather report, mission officials announced at a press conference earlier today at the University of Arizona Science Operations Center. Moving the arm out of its launch configuration was the next major milestone for the mission and Phoenix. “I’m ecstatic to let you know the unstow was successful and the arm is now unstowed and out of its launch restraints,” reported Matthew Robinson, robotic arm flight software lead, of NASA’s Jet Propulsion Laboratory (JPL). “We are just raring to go – raring to go out and get a sample for Peter and the scientists.” The commands to move the arm and continue taking images for the panorama were to have been uplinked to Phoenix Tuesday morning, but because of a glitch with the Electra UHF radio on the Mars Reconnaissance Orbiter (MRO), those commands never got to their destination. Phoenix instead carried out a sequence of preprogrammed activities that including taking more images. As it turned out, MRO successfully returned those images and other data from that preprogrammed sequence back to Earth Tuesday evening. Nevertheless, the Phoenix team turned to Mars Odyssey for Wednesday morning’s uplink. The commands arrived without issue and the lander carried out its tasks with seeming ease. "We've imaged the entire landing site, all 360 degrees of it," announced Phoenix principal investigator Peter Smith, of the University of Arizona, as he showed the image of “the entire scene” around the Phoenix lander. "You can see the lander in a fish-eye view that goes all the way out to the entire horizon. You can see the solar panels out to the east and west and you can see the mast that holds the temperature and wind sensors and at the 9 o’clock position you can see the robotic arm has moved up and off the deck,” he noted. “We’ve noticed we have a very hummocky terrain and it’s divided by troughs between the hummocks,” Smith continued, as he introduced another just-processed image. On Earth, a hummock is a small, dome-shaped uplift of soil created by the pressure of groundwater and is also known as an Earth mound. On Mars, of course, groundwater is the Holy Grail. “In the background, you can see our backshell and our parachute, and close to the lander we see there are some disturbances that were probably caused by our thrusters. This is where we’ll be interacting in this terrain over the next three to six months,” said Smith.
Small “fist-sized” rocks, between five and eight inches are sparsely scattered around Phoenix’s work area. “These are not large rocks-- most are “flat, table-like rocks” -- and we should be able to move them with the robotic arm to see what’s underneath,” Smith said. “We have lots of places between the rocks where we can use our robotic arm and dig down under the surface and see if we can really find that ice layer that Odyssey team promises is just under the surface," he added. "We are now making plans for where to dig first, and what we'll save for later.” So far, things have gone so well with this mission that it almost seems like a fairy tale or, perhaps, a folk legend. It seems fitting then that the Phoenix team has already begun to name the rocks and hollows and “hummocks” within its work space along those themes, beginning with a Humpty Dumpty, the King’s Men, the King’s Horses, and the Wall, and moving on to Sleepy Hollow, Headless, and Ichabod and, finally, Alice, of Wonderland. “We’ll be 100-200 names and this gives the team a chance to have some fun with this,” said Smith. This allows the team to have a little fun with the naming opportunities, because we’re going to use 100-200 names in the mission and this helps us remember what they are.” The entire work area has been deemed a “National Park,” which, Smith said, will be protected at the beginning of the mission. “That’s so we don’t drop things in that area or disturb it in any way, any more than the thrusters have so we can go in and dig our trenches.” The lander’s titanium and aluminum robotic arm was held in place during launch and the 10-month trip to Mars by two restraints, one at the elbow and one at the wrist, Robinson said. When the commands reached Phoenix Wednesday, it was the first time in nearly a year that the spacecraft moved its arm. In a steo-wise fashion, Robinson explain, Phoenix rotated the robotic arm's wrist to unlatch its launch lock, raised the forearm and moved it upright to release the elbow restraint. “And the data looks comparable to the test runs,” he added.
After a health check that tests the arm at a range of warmer and colder temperatures, the arm will soon be tasked with its first assignment: to use its camera to look under the spacecraft to assess the terrain and underside of the lander. In the coming sols, Phoenix will use its robotic arm and its scoop to dig into the icy layers of north polar region and deliver samples to instruments that will analyze what this part of Mars is made of, what its water is like, and whether it is or has ever been a possible habitat for life. Another significant milestone for the mission is the activation of the laser instrument known as lidar, for light detection and ranging instrument. As Jim Whiteway, Canadian Science lead, of York University, Toronto, put it: "The Canadians are walking on moonbeams. It's a huge achievement for us." The lidar is a critical component of Phoenix's weather station, provided by the Canadian Space Agency. The instrument is designed to detect dust, clouds and fog by emitting rapid pulses of green laser-like light into the atmosphere, which, in turn bounces off particles and is reflected back to a telescope. Lidar data can detect dust aloft, for example, to a height of 3.5 kilometers (about 2 miles). "One of the main challenges we faced was to deliver the lidar from the test lab in Ottawa, Canada, to Mars while maintaining its alignment within one one-hundredth of a degree," said Whiteway. "That's like aiming a laser pointer at a baseball from home plate to the center field wall, holding that aim steady after launch for a year in space, then landing," he noted. And the lidar hit a home run. The Phoenix team has made the difficult shift to Mars time. Each Martian day or sol is 24 hours and 40 minutes. That 40 minutes may not seem like much. But it does mean that every Earth day, 8 am, by Earth time standards, for example, is different. For Earthlings, it’s something that day after day can lead to what Martian explorers described as “perpetual jet lag.” No one’s complaining though. Landing on Mars is hard, but landing on Mars and having everything go so well is a huge accomplishment.
"Peter and I were chatting just before this press conference about how even in our wildest dreams things couldn’t have gone as well as they have, not only from the engineering aspects of how the landing went, how the spacecraft is performing, how the payload is performing, but just look at that workspace, it couldn’t be better,” JPL's Barry Goldstein, Phoenix project manager, said via video link from Pasadena. “I’m really looking forward over the next 90 sols for some major scientific breakthroughs. Given some of the sensationalized, confused, and/or misinterpreted news reports about the issue with the Electra UHF radio glitch on MRO Tuesday and other anomalies the team has been working through, Goldstein said: “Everything we’ve faced over the course of these last four sols on the surface of Mars has been relatively benign. The team has been really well rehearsed in terms of anomalies. Our capabilities have been exercised and nothing we’ve done has stressed the team whatsoever and the team has been performing remarkably. None of these activities have been major,” he underscored. “Nothing has stressed the team and we’re trying to make sure everyone knows what’s going on.” The glitch in MRO’s Electra UHF radio was caused by “a transient event,” according to Fuk Li, manager of the Mars Exploration Program at JPL. When that event occurred, the Mars Reconnaissance Orbiter followed its programming and turned the radio off. While that glitch set them back one Martian day -- or sol -- that’s all it set them back, assured Smith. “This [mission] has been in some regards very, very easy,” Goldstein added. “We have far exceeded our most optimistic goals and things are going remarkably well. We have achieved all of our engineering characterization prerequisites, with all the critical deployments behind us We're now at a phase of the mission where we're characterizing the science payload instruments. That's a very important step for us." The Phoenix mission is led by Smith at the University of Arizona with project management at JPL and development partnership at Lockheed Martin, Denver. 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. For more information, log back on as coverage of Phoenix flight continues, and be sure to check out Emily Lakdawalla's Planetary Society Planetary Weblog. 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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