Wary of Another Beagle Moment, ESA Managing Expectations for Rosetta’s Ride-along Lander


PARIS — Call it the Mars Express syndrome, or the anthropomorphism effect: Whatever the name, it is a potential problem for managers of Europe’s Rosetta comet-chaser satellite, which is now heading toward its target following a preset wake-up Jan. 20 after 31 months’ hibernation.

Rosetta is scheduled to make a series of close-quarter flybys of Comet 67P starting in August, gathering and analyzing comet particles and using its 11 instruments in a thorough analysis of the comet from every angle through a series of looping maneuvers around 67P Churyumov-Gerasimenko as it makes its way toward the sun.

If it succeeds, it will be an exploit.

But that is not all. Rosetta is carrying a small lander, named Philae, that will be jettisoned from the satellite in November in an attempt to latch onto Comet 67P by harpoon, Nantucket sleighride style, and hang on long enough to make an even closer analysis of its properties, including subsurface characteristics through the use of a drill.

Rosetta mission managers agree that the risk profile of Philae is much higher than that of Rosetta, which is high enough by itself. They would like those following Rosetta to understand that the mission is by no means a failure if Philae fails in its attempt to hitch a ride.

But how to communicate this fact? Space scientists are just as superstitious as the average citizen, and are wary of saying anything that might jinx a mission.

One European scientist went to far as to wear, on the day of a satellite launch, the same shirt he wore several years earlier, when the same mission had ended in launch failure. The thinking was that a launch failure would not strike the same shirt twice.

But if they say nothing to put at least some daylight between Rosetta and Philae, mission managers risk the Mars Express effect.

Europe’s Mars Express orbiter, launched in June 2003, arrived in Mars orbit around Christmas of that year. It carried the small British Beagle 2 lander, a brave attempt to give Europe a place on Mars’ surface but one that suffered from multiple budget crises. At the time of Mars Express’ launch, mission managers quietly agreed that a Beagle 2 mission success was not the most likely outcome.

Nonetheless, the story of a plucky little lander heading out on its own on Christmas day was too tempting for much of the world’s media. And when Beagle 2 was lost, headlines around the world suggested that Europe’s attempt to get to Mars had ended in a crash landing.

And Mars Express? It entered its operating orbit as planned and during the past 10 years has been mapping the red planet’s surface to create a rich catalog of data, much of it visually stunning. It is still operating.

Philae is more important to Rosetta than Beagle 2 was to Mars Express. Philae carries 10 instruments of its own.

Asked to put Philae in perspective, Rosetta mission managers were reserved, but acknowledged that the Mars Express effect is an issue.

“The transit around Comet 67P is Rosetta’s mission and it has enormous scientific value,” said Alvaro Gimenez, director of science and robotic exploration at the 20-nation European Space Agency, which financed Rosetta.

Matthew Taylor, Rosetta project scientist at ESA, said that while it is probably not accurate to calculate Philae’s value strictly in terms of its instrument count — with 10 sensors, nearly equal Rosetta’s 11 — he would not want to speculate what percent of the mission would be lost if Philae cannot attach itself.

ESA senior scientific adviser Mark McCaughrean also declined to assign relative weights to Rosetta and Philae, but cautioned the media not to fall into the easy trap of assigning human roles to the two machines.

“You can see us getting into a situation where the media play this as the mother, Rosetta, casting her small daughter, Philae, off into this harsh environment,” McCaughrean said. He said that might not be the most helpful way to look at it.