Mars orbiter locates Schiaparelli lander’s crash site
Views from NASA’s Mars Reconnaissance Orbiter released Friday show the crash site where Europe’s experimental Schiaparelli lander fell to the red planet’s surface from a height of several miles, leaving a distinct dark patch on the Martian landscape.
The imagery confirms the loss of the lander on its final descent Wednesday, after successfully plunging through the upper reaches of the Martian atmosphere and deploying a supersonic parachute.
MRO’s low-resolution context camera took a picture Thursday of the Schiaparelli landing site at Meridiani Planum, an expansive plain situated near the Martian equator, and revealed signs of a violent impact.
Something went wrong to cause the landing craft — about the size of a baby grand piano — to free fall from an altitude of up 13,000 feet (4 kilometers), the European Space Agency said in a statement Friday.
Mission control lost contact with Schiaparelli less than a minute before its planned touchdown, and engineers are busy analyzing the lander’s telemetry recorded and replayed by Europe’s ExoMars Trace Gas Orbiter to determine what happened.
The data stream captured by the Trace Gas Orbiter also cut off before touchdown, but it shows the first sign of trouble came about the time Schiaparelli was supposed to jettison its parachute and the back part of its heat shield, then fire nine braking rockets to slow down for landing.
Andrea Accomazzo, head of ESA’s solar and planetary missions division, said Thursday that the data indicate the lander fired at least some of its braking rockets for three or four seconds. They were supposed to burn for around 30 seconds.
Schiaparelli’s Doppler radar, designed to feed altitude and velocity data to the lander’s guidance computer, also activated and operated for a period of time, Accomazzo said.
The image from MRO’s context camera shows two new features attributed to the Schiaparelli spacecraft, including a large dark scar spanning an estimated 50 feet (15 meters) by 130 feet (40 meters). Schiaparelli’s ground team believes it is from the high-speed impact of the lander’s main body.
A little more than a half-mile (1 kilometer) to the south, a bright spot appears in the image, likely the 39-foot-diameter (12-meter) supersonic parachute and part of Schiaparelli’s heat shield, which released from the lander just before ESA lost contact.
“Estimates are that Schiaparelli dropped from a height of between 2 and 4 kilometers (6,500 to 13,000 feet), therefore impacting at a considerable speed, greater than 300 kilometers per hour (186 mph),” ESA said in a statement Friday. “The relatively large size of the feature would then arise from disturbed surface material. It is also possible that the lander exploded on impact, as its thruster propellant tanks were likely still full.”
Schiaparelli ended up about 3.4 miles (5.4 kilometers) west of its intended touchdown target, well within the landing ellipse.
During the last phase of the descent, Schiaparelli’s hydrazine-fueled landing rockets were supposed to slow the spacecraft from around 120 mph (200 kilometers per hour) to a walking pace at an altitude 6 feet (2 meters) above the surface. At that point, measurements from the lander’s radar altimeter would tell the thrusters to shut down, and Schiaparelli was to fall to the surface cushioned by a crushable carbon-fiber structure.
The battery-powered lander was expected to function for at least four days, collecting weather data on the surface and returning imagery taken by a descent camera during the landing sequence.
MRO’s higher-resolution HiRISE camera will be tasked to get a closer look at Schiaparelli’s wreckage next week, ESA said. The sharper views from HiRISE, essentially a downward-facing telescope on the orbiter, might better identify debris and individual components from the spacecraft.
Schiaparelli traveled to Mars piggyback aboard the Trace Gas Orbiter, which steered into orbit around the red planet at the same time as the landing probe’s ill-fated descent. The two spacecraft separated Sunday to arrive at Mars on different trajectories.
The two spacecraft launched in March from the Baikonur Cosmodrome in Kazakhstan on top of a Russian Proton rocket, the first of two missions to Mars under the auspices of the joint European-Russian ExoMars program.
The Trace Gas Orbiter, or TGO, is operating normally after accomplishing a critical main engine burn Wednesday, circling Mars in an orbit with a high point of around 62,750 miles (101,000 kilometers) and a low point of 2,293 miles (3,691 kilometers). The orbiter completes one lap around Mars every 4.2 days, ESA said, very close to engineers’ predictions.
Ground controllers plan to switch on the TGO’s instruments next month for eight days of observations. Beginning in March, the orbiter will dip into the upper fringes of the Martian atmosphere on each orbit, using aerodynamic drag to pull the spacecraft into a tighter, circular orbit around 250 miles (400 kilometers) in altitude.
The “aerobraking” campaign will continue for most of 2017, and the TGO’s regular science observations should begin by the end of next year.
The orbiter carries sensors to detect gases like methane in the atmosphere, a possible signature of ongoing biological or geological activity on the red planet. Scientists hope to identify the source of trace levels of methane from the orbiter’s measurements.
The TGO also has a camera to help create maps of the Martian terrain, and a Russian instrument to find water resources hidden just below the surface. The orbiter will also serve as a relay station for Mars landers, including the European-built ExoMars rover scheduled for launch in July 2020 and NASA’s fleet of robots exploring the red planet.
Built by Thales Alenia Space and funded mainly by Italy, Schiaparelli was an experimental mission seeking to become the first European spacecraft to successfully land on Mars. The UK-led Beagle 2 lander touched down on Mars in 2003, but ran into trouble before it could contact Earth.
ESA plans to employ the same radar and computer design flown on Schiaparelli on a more ambitious joint European-Russian Mars lander to launch in 2020. That will be the second phase of the two-part ExoMars mission.
In a blog post on ESA’s website Friday, Jan Woerner, the agency’s director general, wrote that lessons learned from Schiaparelli’s failed landing could still turn the mission into a success by improving the reliability of the ExoMars rover’s descent system.
“From the data received we have already learned that contact stopped very late in the descent,” Woerner wrote. “This means we will obtain information from a close analysis of the data that Schiaparelli was built for, notably on the performance of elements such as the heat shield, parachute, radar, thrusters and so on. This information can subsequently be used to improve the design of the 2020 ExoMars mission, since in that mission the survival of the descent module will be of real scientific relevance.”
The ExoMars rover will ride through the atmosphere on a Russian-built descent stage aided by European elements in its guidance system — like the radar and computer — and drive off its landing pad to drill more than 6 feet (2 meters) underground, deeper than any previous mission. Scientists will search for signs of life hidden beneath the top level of Martian soil, where biomarkers from existing or extinct life could be shielded from the damaging effects of ionizing radiation present at the surface.
Woerner said the importance of the two elements of the 2016 mission could be weighed as 80 percent and 20 percent for the TGO and Schiaparelli, respectively. Engineers received at least 80 percent of Schiaparelli’s telemetry during its descent, therefore, the combined mission should be considered 96 percent successful, he wrote.
“So to sum up where we stand, we have achieved a successful orbit insertion of TGO, ready to perform science and act as a relay station for ExoMars 2020 ground science,” Woerner wrote. “Not only that, but we have received a large quantity of data from the lander giving us crucial information to help us perform a successful landing of the next mission.”
The next hurdle for ExoMars may be political, not technical.
ESA earlier this year announced the rover mission would not be ready for launch in May 2018, as previously planned, and delayed the launch to the next Mars launch opportunity in July 2020.
The delay, which requires ESA keep paying scientists and engineers for two more years, added to a funding shortfall already facing the ExoMars program.
ESA plans to ask its member states to commit up to $330 million (300 million euros) in extra money to the ExoMars program in a previously-scheduled meeting of European government ministers in Switzerland in December.
The first and second biggest financial backers of the ExoMars program are Italy and Britain, respectively, and the lion’s share of development and fabrication of key parts of the mission — from the TGO, to Schiaparelli, to the rover — is taking place in those countries.
Woerner told reporters Thursday the success of the Trace Gas Orbiter, and the data from Schiaparelli, should demonstrate to European ministers that the extra money for ExoMars is worth the investment.
“I think they will see, and we will show, that this mission is a success,” Woerner said. “We have the function which we need for the 2020 mission. I think that we don’t have to convince them. We just have to show them. The results are obvious.”
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21 Oct, 2016
Mars orbiter locates Schiaparelli lander’s crash site
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