Scientists Move Comet Lander in Effort to Boost PowerJohn Lauerman and Alex Morales
After putting the first-ever scientific lander on a comet, the project’s leaders shifted its orientation in an effort to preserve its life and continue studying the origins of the solar system.
Researchers at the European Space Agency, the international group overseeing the Philae comet lander, performed a “lift and turn” yesterday to move the apparatus into the sun, the agency said on Twitter. Without a recharge from solar power, the vehicle’s batteries would have died in less than a day, said Stephan Ulamec, project manager for the lander.
Systems on Philae shut down just after midnight U.K. time as the battery fell into standby mode because there was not enough sunlight to recharge, according to a blog post on ESA’s website. The next possible communication with the comet lander will come this morning.
ESA, a consortium of researchers funded by 20 nations, spent almost two decades building the Rosetta probe that carried the lander and maneuvering it 4 billion miles to the side of a comet headed for the Sun. Upon its initial touchdown, the craft bounced out of its intended, well-lit resting place, spurring the scientists to develop a plan to try to continue its work.
“It was a fantastic result that we landed on the comet,” Ulamec said in a telephone interview before the maneuvers. “Of course we’re all keen on extending this.”
Ulamec said one option considered was to turn the lander’s solar panels into a position that might get more exposure. Another was to try to push it by running the flywheel, a gyroscopic stabilizing device that kept the lander upright during landing.
“The flywheel gives it a ‘kick’ in the low-gravity environment,” Ulamec said. To carry out the maneuver, “we need energy, and I’m not sure the energy is available.”
Philae bounced twice after failing to deploy its anchor harpoons on touchdown three days ago, leaving it far from the planned landing site and in the shadows. Its solar cells were receiving about half the sunlight needed to reboot the lander and take measurements, scientists said. The initial battery-powered phase was planned to last for about 64 hours, according to an agency statement.
ESA sent commands for Philae to drill for samples from the comet, even though that risks dislodging the unanchored lander, said Paolo Ferri, head of mission operations. The plan was to gather samples from as deep as 23 centimeters (9 inches) below the surface. They can then be lifted up into an oven in the probe and heated to test for elements and molecules.
The lander reported data to the agency last night showing the drilling operation had been successful. The agency also reported that it had rotated Philae 35 degrees in the effort to find more sunlight for its solar panels.
“Looks like a whole new comet from this angle,” the agency said on Twitter.
While the lander sent data and photos for more than two hours after the maneuver, scientists said they wouldn’t know until today at the earliest whether the operation had shifted the solar panels into the sunlight to power the craft.
The agency has sought to gather as much data as possible about the Churyumov-Gerasimenko comet from Philae’s instruments before doing anything that might dislodge it from the surface, including deploying the drill.
Three months ago, the European mission’s Rosetta spacecraft became the first to orbit a comet. Philae separated from Rosetta on Nov. 12, embarking on a seven-hour descent to the surface of the rubber-duck shaped comet in the first such landing.
The comet, lander and probe are moving at 18.3 kilometers (11.4 miles) a second. Researchers hope that by studying the icy mass they can uncover clues about the early formation of the Earth because comets may have seeded the planet with water and the organic molecules needed for life.
The comet’s orbit also suggests that it may be a relative of ancient, relatively unchanged objects found at the far reaches of the solar system, called the Kuiper Belt, said Joel Parker, a director at the Southwest Research Institute in Boulder, Colorado, who’s a member of the Rosetta science team.
“It could be sort of a cousin of Pluto,” he said. “A very small cousin.”
The project also hoped to suggest ideas as to how Earth might protect itself against collisions with comets and asteroids, Parker said. Understanding the composition of Churyumov-Gerasimenko might help defend against events like the 1908 Tunguska blast, believed to be caused by an asteroid, that leveled trees over hundreds of miles in Siberia.
Scientists are particularly interested in how the comet changes as it approaches the Sun, flying into the stiff solar wind that creates its characteristic fiery tail. Instruments on board the lander will need power to carry out those observations, Parker said.
With a full dose of solar power, Philae has the potential to keep taking measurements into March, Parker said. At that point, dust on the panels would probably rob it of any further energy, he said.
Scientists are still hoping they can keep Philae going, Ulamec said.
“There’s a lot more one could do in long-term science,” he said. “We have the capacity to do many additional experiments and observe how the comet evolves on its way to the Sun.”
Rosetta launched in March 2004 and has been orbiting the comet since Aug. 6. Its 6.5 billion-kilometer journey has taken Rosetta as far as 1 billion kilometers from Earth. It’s now orbiting about 22.5 kilometers above the comet, more than 500 million kilometers from Earth and about 450 million kilometers from the Sun, between the orbits of Mars and Jupiter, according to ESA’s website.