DARMSTADT, GERMANY—There’s good news and bad news tonight from the European Space Agency (ESA). Its Trace Gas Orbiter (TGO), the first prong of a multipart ExoMars mission, appears to have been captured into its planned orbit around Mars and is working normally. But the Schiaparelli lander, a testbed for future landing technologies, is missing in action. “Something went wrong, at least in the communications,” Paolo Ferri, ESA’s head of mission operations, told reporters here at ESA’s control center. Mission engineers will be working through the night to process the scant data from the probe to try to find out what went wrong and whether recovery is possible. “There’s a very good chance that by the morning we will know either that the lander is lost or how to recover it,” he says.
During its 6-minute descent to the surface, Schiaparelli broadcast basic telemetry data but in a weak signal, designed to be picked up and recorded by the TGO for later transmission to Earth. The TGO at the time was in the middle of a 2-hour-long burn maneuver to enter Mars's orbit and wasn’t able to communicate with Earth. But two other receivers were trained on Schiaparelli: ESA’s 13-year old Mars Express orbiter and the Giant Metrewave Radio Telescope (GMRT) in Pune, India. Neither instrument could interpret the telemetry data, but the nature of the radio signals alone offered some insight into the lander’s descent.
From the signals received at Pune, managers followed the descent in real time and, initially, everything seemed to go to plan. The GMRT saw Schiaparelli power up right on schedule. They also saw it slowing down as it entered the atmosphere. But less than a minute before it was due to land, the signal was lost. That didn’t cause undue concern at the time because detecting this extremely weak signal all the way from Mars was an experimental technique, and any number of things could have interrupted the signal. But managers really got worried when the data relay from Mars Express showed the lander’s signal breaking off at just the same moment. “It’s clear we lost the signal from the lander, but we don’t know where it happened in the sequence of events,” Ferri says.
Once the TGO emerged from behind Mars and confirmed that it had entered orbit, it also reported that it had received the telemetry from Schiaparelli. Those data have yet to provide any answers, however. Ferri says the TGO requires about 3 hours to process the 20 megabytes of data it received from Schiaparelli before it can be transmitted, so mission managers won’t be able to even start analyzing it until after midnight local time. Time is critical, because Schiaparelli’s batteries will last only a few days on the surface, so if contact is to be reestablished it has to be done soon.
Ferri didn’t want to speculate on what might have gone wrong, but he did give one example. When the lander jettisons its heat shield at a 1-kilometer altitude, data transmission switches from an antenna on the shield to one on the lander. If that second antenna were damaged, it could account for the loss of signal.
The plan was for Schiaparelli, once on the ground, to transmit a much more detailed data set about the descent up to a passing orbiter for relay to Earth. The first to pass over the landing site was NASA’s Mars Reconnaissance Orbiter (MRO), and at the time of writing it was unclear whether NASA had any data in hand via MRO. Ferri says that, considering the earlier loss of signal, the “chances are slim” that MRO has anything.
ESA officials are keen to point out that they had succeeded in their main scientific goal: getting the TGO into orbit so it can begin searching for gases like methane that could signal life. “It’s been confirmed by hard numbers,” says Michel Denis, the ExoMars flight director at the European Space Research and Technology Center in Noordwijk, the Netherlands. “We have a mission around Mars, another one.”
And even as ESA officials brace for the worst with Schiaparelli, they were trying to find a way to make lemonade out of lemons. As long as they can find out the cause of the lander’s troubles, they will be better prepared to land a larger ExoMars rover in 2020, and the mission could still be viewed as a partial success. “Yes, it worked. We just don’t know all the details yet,” Ferri says. “Keep your fingers crossed and we hope we’ll have some positive results overnight.”
*Update, 19 October, 5:00 p.m.: This story has been updated with information about the uncertain status of the Schiaparelli lander.