Twelve years ago, the European Space Agency’s Rosetta probe took launched from French Guiana for a 10-year journey to rendezvous with Comet 67P. Its sidekick, a robotic lander named Philae, gained international attention when it had a bumpy landing on the comet in November 2014. Philae — the little lander that could — remained operational for a couple weeks before falling into hibernation as its battery weakened. It maintained sporadic communication thereafter. The episode gained international attention, depicted in a number of charming comic updates released by ESA.
The Rosetta spacecraft has now joined Philae on Comet 67P. Yesterday, the probe began a 13-hour free fall that ended in a (relatively) gentle crash at the Ma’at landing site at 6:39 a.m. ET on Friday. During its decent, the spacecraft snapped a series of images of Comet 67P with its OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) camera. The stunning photos reveal the comet’s bulbous “head,” jagged cliffs, and shadowy crevasses in unprecedented detail. It took roughly 40 minutes for the data to beam back to Earth.
Although Philae was designed to handle the impact of its landing, Rosetta was not. ESA published images of the signals it received from Rosetta during its last half hour in restful operation.
The Rosetta mission was marked by expected discoveries and surprises of the comet, which scientists see as a cosmic time capsule that can help unlock the history of our solar system.
When the spacecraft first arrived at 67P, a few months prior to Philae’s rough landing, the OSIRIS camera captured data that confirmed the comet’s irregular shape and structure. In September 2014, ultraviolet wavelength images showed that the comet’s surface was surprisingly dark and detected the presence of hydrogen and oxygen. Scientists were confident the comet would contain water ice due to its distance from the sun but, to their surprise, none was found. The significant ratio of heavy water to normal water on the 67P — nearly three times that found on Earth — suggested that the origin of water on Earth is unlikely from similar celestial bodies.
Regardless, any discovery can be considered a good discovery and, despite the challenges faced by both Philae and Rosetta, the mission’s ability to overcome adversity and transmit valuable data made it an overall success.