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Planetary News: Phoenix (2008)Phoenix Rises from the Ashes in StyleBy A.J.S. Rayl
PASADENA -- "This is a scientist's dream." Peter Smith, of the University of Arizona, the chief scientist for Phoenix, had a really good night Sunday, a night that ranked in life moments "somewhere between Mom and apple pie," as he put it. The tattoo, lucky hat, and peanuts worked: he couldn't have asked for anything more. Neither really could anyone else on the team. Phoenix performed its entry, descent, and landing on Mars "flawlessly," according to Lockheed Martin's Ed Sedivy, Phoenix spacecraft manager. The E-D-L, as landing on other planets is commonly known, was relayed to Earth through the Mars Odyssey orbiter as planned, with the Mars Reconnaissance Orbiter (MRO) and the European Space Agency's Mars Express collecting data for playback later. "The spacecraft stayed in contact with Earth during that critical period, and we received a lot of data about its health and performance," Sedivy confirmed. The parachute, it turned out, opened 6.5 seconds later than slated and so every event after that also initiated a little later. At the end of the ride, touchdown was still only 7 seconds later than predicted. The spacecraft landed going five miles per hour, about one-quarter of a mile an hour, or "one-eighth of a casual stroll in the park," as Sedivy described it. Radio signals received at 4:53 pm Pacific Daylight Time [7:53 pm EDT] confirmed Phoenix had survived its "seven minutes of terror" and touchdown 15 minutes earlier. It appeared from the telemetry that Phoenix pirouetted down right on the edge of a redefined targeting ellipse in the arctic region known as Vastitas Borealis, at 68 degrees north latitude, 234 degrees east longitude. "We didn't obliterate the site with the thrusters, which is fascinating and good," noted Barry Goldstein, Phoenix project manager, of JPL. "All the data shows we came down with almost zero vertical velocity, at .1 meter per second horizontal velocity." The signal confirming that Phoenix had survived touchdown and the transmission of the first pictures were uplinked to Odyssey and received on Earth at the Goldstone, California antenna station of NASA's Deep Space Network (DSN). "We were dead solid all the way down," Sedivy said. "We're a little bit farther down range than we were expecting . . . but when you look at all the parameters that we have from the performance of the systems during E-D-L, it went better than any simulation we ever did," he said. "The team in Denver is totally stoked. The spacecraft nailed it and we couldn't be happier. It's in great shape. We did it. We did it with style."
It was NASA/JPL's fifth successful landing on Mars of six attempts, its first rocket-controlled or "soft" landing since Viking in 1976 -- and it was textbook. Somehow, the Phoenix team had made it look easy. Up on Mars, once Phoenix waited 15 minutes for the dust to settle, then opened its solar arrays, just like it was supposed to, deployed its camera and weather station mast, and began taking images to send home. The first pictures were the traditional engineering shots -- of the solar arrays to make sure they unfolded properly, of the masts for the stereo camera and weather station to see if they had swung into vertical position, and of its 7.7-foot robotic arm and its biobarrier shield. Then, in what is an almost wistful picture (for those over 45) Phoenix snapped a picture of its footpad. The footpad image was for the science and it was every bit as much in homage to the twin Vikings, the last spacecraft to soft-land on Mars. All those 32 years ago, Viking's very first picture was of its footpad. Then Phoenix looked out and around and snapped a few quick landscape and terrain images, all of which arrived at the Jet Propulsion Laboratory (JPL) and the University of Arizona Science Operations Center about two hours after the landing had been confirmed. Ooohhhs and ahhhhs seemed to permeate the scene at JPL and a kind of calm emerged amidst the excitement of the holiday weekend. The landing area had been thoroughly imaged by the University of Arizona's High Resolution Imaging Science Experiment (HiRISE) camera onboard MRO prior to landing and there were no surprises. The terrain images showed what appeared to be a rolling plain with polygonal shapes cracked into the surface, much in the way mud cracks at the bottom of a riverbed when it goes dry.
"I know it looks like a parking lot, but it’s a safe place to land," defended Smith, somewhat tongue in cheek. "There's ice under this surface – it doesn't look like it, but it's down there. We see the lack of rocks that we expected. We see the polygons that we saw from space and these troughs. Over the next few days, we'll be getting [images of] the whole scene. I couldn't be more pleased. This is a scientist's dream." Even before the post landing press conference at JPL had ended, Phoenix team members managed to process one of the images, a narrow swath of the landscape, in color and posted it on the Internet. The team got little sleep last night and in Tucson especially they burned the midnight oil – on Mars time now – sending the spacecraft its To-Do list for the day, and examining and processing the very first images ever taken from the surface of Mars' polar regions. All images from the mission are being released to the public as they come through the Deep Space Network (DSN) pipeline and are distributed to the mission's scientists and engineers. "Seeing these images after a successful landing reaffirmed the thorough work over the past five years by a great team," said Goldstein, who thanked the mission's partners and contributors, a long list. "This is a huge collaboration," he pointed out. Remarkably, there was no evidence of dust on the solar arrays or on the deck of the lander. Whatever dust Phoenix did kick up, apparently, was minimal or settled fast or both. Meeting the press at the post-landing conference in von Karman Aditorium at JPL, was NASA Administrator Michael Griffin, Ed Weiler, the associate administrator for science from NASA headquarters, JPL Director Charles Elachi, Smith, Goldstein, and Sedivy, all of whom were listening to the landing events from inside the JPL Phoenix mission control room.
"For the first time in 32 years, and only the third time in history, a JPL team has carried out a soft landing on Mars," NASA Administrator Griffin said officially after the landing. "Experts make it look easy," he said speaking first at the press conference. "Today you've had a chance to watch a team in action making something that is incredibly hard to do look easy. You know they are the most expert of the expert to do that," he noted. "One measure of that expertise [is that] accuracy at entry interface had to be well inside 20 kilometers of error, after a 650-million kilometer trip from Earth to Mars," Griffin continued. "That's something like fewer than one part in 10 million of accuracy. Very few things that human beings do in any walk in life are as precise and accurate as one part in 10 million. That's the kind of accuracy and precision [with which] navigation is done here at JPL, one of the technical pinnacles of the space business. There are many more measures of the kind of expertise that have to be applied to pull off what you saw here today. But I'd like you to think about that one part in 10 million." Weiler did just that. "Doing something to that accuracy is like trying to hit a hole-in-one, but you tee off in Washington and hit the ball 10,000 miles and hit the hole-in-one in Sydney, Australia," he said. "You have to remember -- that hole is moving," added Elachi to an eruption of cheers and applause. "Throughout history, exploration always required courageous people and people who have superhuman dedication," Elachi continued. "It's courageous people who have put Phoenix on Mars. Many people thought this will not be possible, that we would not be able to succeed. All of us knew this was a very risky mission, but tonight this team made history was possible. They will be remembered forever for being the first people to explore the polar region of Mars and there is no telling what discoveries we'll be seeing over the next 90 days," he said, noting that every NASA center contributed to this program.
"We also had some of the best of academia as exemplified with the University of Arizona and Peter the best of industry as exemplified by Lockheed Martin," Elachi added. "One thing I want to ask you, next time it's clear and you go outside and look at Mars – think – our nation has three spacecraft on that planet – Spirit, Opportunity and the order of the Phoenix." When it couldn't get any better, it would. MRO's HiRISE camera – which is also from the University of Arizona and on which Smith worked – got that picture of Phoenix landing on Mars, right after it deployed its parachute. It is, by all space geek accounts anyway, an absolutely jaw-dropping picture. The Hi-RISE team had also been burning the midnight oil on behalf of Phoenix and at Monday morning's press conference, Goldstein made the announcement. It is the first picture ever taken by one spacecraft of another spacecraft in the process of landing on Mars, a notable milestone in space exploration history – and photography. Sweeter still for Smith, who actually worked on Alfred McEwen's Hi-RISE team before his Phoenix was given wings. The remarkable picture shows the parachute about 3 meters (about 10 feet) wide fully inflated. The bright pixels below the parachute are the aeroshell with the Phoenix lander still tucked inside. The parachute and aeroshell appear bright against the darker, but fully illuminated Martian surface. Even more astonishing, the very thin cords connecting the aeroshell and the parachute are faintly visible. That was the biggest surprise for McEwen.
"There was some luck involved in getting this image," confirmed MRO Project Manager Jim Erickson. For one thing, HiRISE usually points downward. To get this shot, the pointing was at 62 degrees, nearly two-thirds of the way from straight down to horizontal. To tilt the camera, the whole orbiter must tilt. MRO was already pointed toward the expected descent path of Phoenix to record radio transmissions from Phoenix. "We've never taken an image at such an oblique angle before." McEwen said Add to that the fact that camera pointing for the HiRISE image used navigational information about Phoenix updated on landing day, so neither the camera team nor the mission team would know until the camera shots were sent to Earth whether it had actually caught Phoenix. And, there it was. "We saw a few other bright spots in the image first, but when we saw the parachute and the lander with the cords connecting them, there was no question," McEwen said " it's on my top 10 favorites list," he added. HiRISE took the image at around 11:35 pm UTC, from an altitude of 310 kilometers (193 miles), at a velocity of 3.4 kilometers (2 miles) per second, with the distance to Phoenix being 760 kilometers (472 miles). Smith called the picture "awesome."
It floored the project manager. "I'm absolutely floored," said Goldstein, who admitted at this morning's press conference that he had been skeptical of the idea. "But this is a spectacular image from the Mars Reconnaissance Orbiter, an engineer's delight," he added. "I tip my hat to the MRO team and congratulate the HiRISE team." The first-of-its-kind photograph is more than just an amazing picture. It's data that will be used to reconstruct entry-descent-landing events, Goldstein said. HiRISE team members have posted a processed version of the image on the HiRISE Website. For full resolution, go to: http://hirise.lpl.arizona.edu. McEwen's team is already searching another HiRISE image for the landed Phoenix and its parachute, heat shield and backshell on the ground. McEwen said his team plans to take two more HiRISE images of the landing area in the next few days, including a stereo view that will give the Phoenix mission scientists the context of where they will be digging. "Seven minutes of terror are being followed by three months of joy," Goldstein summed up at this morning's press conference. The detail, observations, and realizations that Smith's closer inspection of Phoenix's first images underscored that. "We see fresh cracks which may be a sign of ice," Smith pointed out. "These cracks can't be old. If they were, they would fill in with sand or ice. We notice that some of the rock patterns don't line up with the polygons, it's like they're remnants perhaps of a more ancient surface. As for what's under the rocks, I’m anxious to find out," he said. He's sure they'll hit paydirt, errr paywater-ice. "We can see cracks in the troughs that make us think the ice is still modifying the surface," Smith noted. "When you look at some of those troughs up close, you actually see what looks like freshly dug depressions in the center of them and this is just like the active surfaces you see in the Arctic regions on Earth, so it implies that we have an active surface. In other words, the ice is still there and expanding and contracting with the seasons."
In the image of the footpad, it's obvious Phoenix's slide a bit into the soil, a sign the digging will be good. And Mars is cooperating: it was a little warmer when Phoenix set down Sunday, around -33 degrees Fahrenheit as opposed to -50 as expected. Then there was a noticeable white feature, visible in one of the shots that shows the landscape and horizon, something Smith said they would be re-photographing soon, probably toward the end of next week. From its site, Phoenix will use its 7.7-foot robotic arm to dig for the first time ever into the ice-rich permafrost and scoop up samples of soil and water-ice from beneath the surface, bring them back to the spacecraft for analysis. Phoenix will spend at least three months investigating the history of the water in the polar ice, looking into whether the subsurface environment in the far-northern plains of Mars has ever been favorable for sustaining microbial life, and assessing the biological potential of the ice-soil boundary. "The Phoenix mission is one where we land and dig into the surface," as Smith explained it. "Getting a scoopful of icy soils really our goal and to understand the history of that ice in the polar circle and how it relates to the hydrologic cycle. On Earth, we have oceans, snowy mountains and rivers flowing from the mountains to the oceans. It's quite different on Mars, but there is water vapor in the atmosphere and ice in the polar regions and they do interact and we're trying to understand that interaction. We'll also be looking into the icy soils and looking for a habitable zone." The spacecraft also carries a Canadian-supplied weather station and to study the weather in Mars' arctic region. Coordinated observations are planned with the orbiters above to get a top-down analysis of the polar atmosphere.
Today, on its Sol 1, Phoenix began conducting instrument and systems checkouts, plus took some more pictures of the lander deck, robotic arm and Biobarrier, which apparently did not quite set up all the way, which isn't seen as much of an issue, according to Goldstein. During the next week or so, the Phoenix team will "characterize" their spacecraft, checking out the performance of its power and thermal systems, as well as it robotic arm and science instruments. After that, Phoenix will dig and scoop up its first sample of surface soil and bring it back to the Thermal and Evolved-Gas Analyzer (TEGA) onboard Phoenix. There, and in the Microscopy, Electrochemistry, and Conductivity Analyzer, the chemical analysis will take 10 to 15 days, if all processes go well. Phoenix can scoop and analyze 22 samples and the plan is that each additional sampling cycle will reach a deeper subsurface level, in increments of about two to three centimeters. The collection and analysis of samples at each different layer is expected to take 10 to 15 days, barring operational difficulties. How soon the digging reaches the expected icy layer will depend on how far below the surface that layer lies. Prior to landing, estimates range from two to five centimeters. If the ice is at the deeper end of that range, the first analysis of an icy sample could come as early July. In any case, a deluge of data likely to come and today and team acquired a bump in data rate, from 32 kilobits a second to 128 kilobits a second that should ease the flow through the "pipeline." Phoenix will eventually shoot a 120-degree panorama to the south, Smith said, and a key milestone still ahead is the first use of the lander's 7.7-foot-long robotic arm, which he said may happen tomorrow. The first soil sample could be scooped in as early as a week. Although they now know Phoenix is within a 100 meter x 300 meters square, Goldstein said the team is still trying to home in on precisely where the spacecraft is. The specifics, down to the centimeter no doubt, will come in the next few days. Wherever it is, it's lived up to its name, rising up from the ashes of past missions that didn't make it. Hardware from the Mars Surveyor 2001 Lander, which was canceled after Mars Polar Lander crashed onto the surface in 1999, as Smith saw it, was a resource for pursuing a new science opportunity. So he and his colleagues developed a plan to bring the Surveyor spacecraft out of storage, thoroughly analyze and test it, resolve all known problems, and add upgrades so it could pursue a new set of science goals. A few months earlier, Odyssey discovered that plentiful water ice lies just beneath the surface throughout much of high-latitude Mars and thus Phoenix emerged.
Phoenix took with it a time capsule from Earth, a silica glass mini-DVD provided by The Planetary Society that contains a collection of Mars-related literature, art, and audio called Visions of Mars, with contributions from Planetary Society co-founder Carl Sagan, and science fiction authors Isaac Asimov, Ray Bradbury, Arthur C. Clark, among others and the names of more than 250,000 people who wanted to "ride" along. The disk, designed to last hundreds of years, is sent with the hope that future explorers, from wherever they may hail, will one day find the message. With barely 24 hours on the surface, it's already soaring toward its expectations, logging its first mission objective officially today by establishing two-way communications with both Odyssey and MRO. After all the anticipation, anxiety, and drama and excitement of the landing, the real work begins. "Get to work," Smith told his students through the electronic links to the University of Arizona Phoenix Science Operations Center. "Start building that Mars terrain. We're coming home tomorrow." Although the $520 million mission is funded for 90 days or three months, "we're going to operate it until Mars freezes over," said Goldstein. "All vehicles have different limited resources," Goldstein continued. "On MER [Mars Exploration Rovers Spirit and Opportunity] our limiting factor was dust on the solar arrays. The reason MER has lasted so long is we didn't levy a requirement on Mars to blow the dust off, but it cooperated for us and the rovers have been running like the Energizer bunny." Unlike the rovers, which rove, can tilt their solar arrays, and have been smiled upon by Martian wind gusts that have cleared their solar arrays, Phoenix is a solar-powered lander and will not rove or move from its present position. "The one thing that can't count on with Mars is for it to change its orbit or to stop its orbit around the Sun," Goldstein said. "The limiting factor on Phoenix is the Sun is going to go away. Right now, we are above the arctic circle and we have the Sun up 24.6 hours a day, so we have lots of energy. But after we got to Sol 90, if you look at the curve of the number of hours the Sun is above the horizon, it dips radically." That noted, Goldstein speculated that Phoenix could survive for 120 to 150 sols or Martian days. Beyond being the world's first Martian arctic explorer, Phoenix is the first NASA mission being led by a public university and The University of Arizona has the honors. "This is historic," said UA President Robert N. Shelton, who was at JPL during the landing.
Mission operations are expected to roll over to Arizona's Phoenix Space Operations Center once the spacecraft has landed, stretched out it solar array "wings," and tested its long robotic arm. That shift is expected to occur on Wednesday, May 28. Scientists can learn a lot by studying this area of Mars. "The polar region on the Earth after 100 years of scientific investigation is known to be a place where quiet records are preserved and where you can find a lot of information about the history of life on Earth," Smith elaborated. "It is preserved in the ice, the deep freezer of the Earth and perhaps this is true of Mars, too. By analyzing the chemistry and mineralogy of the soil and ice using robust instruments, scientists will better understand the history of the Martian arctic and determine whether or not it is habitable. "And that is, as Smith put it, "the business of the Phoenix mission." Finding life, if any should exist, will be the charge of a future mission. "We don't have the instruments onboard to detect life," said Smith. If, however, there should be sizeable bugs, clearly the Phoenix cameras would image them. So Mars has captured our attention again. "But you're going to have to have some patience here," Smith said to reporters. "This will be unfolding slowly over the next few months." 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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