The European Space Agency’s landing of a spacecraft on a comet, a first for humankind, provided a welcome and refreshing break for a space community that recently has made global headlines for all the wrong reasons.
Like the October failures of Orbital Sciences Corp.’s Antares rocket and Virgin Galactic’s SpaceShipTwo rocket plane, the successful touchdown Nov. 12 of ESA’s Philae lander on the Comet 67P/Churyumov-Gerasimenko grabbed the attention of the general public. And with good reason: The degree of difficulty was such that the likelihood of failure was widely viewed as greater than that of success. That might explain the absence of key ESA government officials from events related to the landing.
But succeed it did in a sequence that was captured by a camera aboard the 3-ton Rosetta mothership that had brought Philae to the comet over a 10-year journey that covered some 6.4 billion kilometers. The tense moments leading up to the touchdown, and the relief and jubilation that followed, were reminiscent of NASA’s landing, in August 2012, of a 1-ton rover on the surface of Mars using an unlikely looking contraption known as the Sky Crane.
The success cannot help but generate good will among ESA members on the eve of what could prove to be a landmark ministerial conference aimed at setting the agency’s future priorities, on which key several members differ. News that France and Germany had come to terms on a future launcher strategy ahead of the meeting was a positive development in that regard, although one must assume that the timing in relation to Philae’s landing was purely coincidental.
Of course, the landing did not go exactly as planned. While Philae originally touched down on its assigned spot on the rocky comet, it failed to secure itself to the surface and effectively bounced, not once but twice, before finally settling down on a spot about a kilometer away. Unfortunately, that spot was in an area where sunlight is scarce, leaving Philae unable to recharge its batteries, which consequently ran out of juice some 57 hours later.
Philae was nonetheless able to collect a wealth of data — 63 hours’ worth if its descent to the surface is included — which it was able to transmit back to Earth via Rosetta before going into what could be a permanent hibernation mode. Much to their credit, ESA managers, who had scheduled Philae’s data collection tasks based on the expectation that it would operate for much longer, were able to quickly reorder the agenda when it became apparent that the mission would be cut dramatically short.
ESA managers have since confirmed that the instruments that were activated operated as planned, although many questions — notably whether Philae was able to collect and analyze a Comet 67P soil sample — remain unanswered, at least for now. Agency officials are holding out hope that as the comet gets closer to the sun in the coming months its solar arrays will be able to capture enough sunlight to recharge its batteries, enabling more scientific data collection.
In the meantime, scientists will have plenty of fresh data to work with that should go a long way toward unlocking some of the longstanding mysteries surrounding comets, whose eccentric orbits around the sun make them visible from Earth for only brief periods of time. Already Rosetta and Philae have sent back stunning images of Comet 67P, and Rosetta will continue to chase and gather data on the object for another 18 or so months. There can be little doubt that the Rosetta mission will provide a new foundation for the scientific community’s understanding of comets, notwithstanding Philae’s truncated operations on the surface.
Here’s hoping ESA’s optimism that Philae can resume its science mission proves to be well founded. Even failing that, the mission has been successful both from a purely scientific point of view and for generating a global buzz beyond the friendly confines of the space community.
The lesson to be learned within the community is that when it comes to robotic exploration of the solar system, it always pays to aim high and take risks — within bounds of reason, of course. As with the NASA Curiosity rover’s successful Mars landing, Rosetta and Philae have demonstrated that there’s a perpetual — if occasionally elusive — pool of underlying public enthusiasm and support for challenging space endeavors that’s there for the taking with the right combination of chutzpa, drama, science and skill.
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