The Rosetta spacecraft, which orbits the comet, captured this series of images of the Philae lander bounding off the surface. The precise spot the lander came to a stop remains unknown. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA hide caption

itoggle caption Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Onlookers take cell phone pictures of stranded window washers hanging from scaffolding on the side of One World Trade Center. Timothy A. Clary/AFP/Getty Images hide caption

itoggle caption Timothy A. Clary/AFP/Getty Images

The ESA released this composite panoramic image showing Philae's surroundings on Comet 67P. To illustrate the lander's orientation, the agency superimposed a sketch of the craft. ESA Rosetta/Philae/CIVA hide caption

itoggle caption ESA Rosetta/Philae/CIVA

Engineers at the European Space Agency fear that they won't be able to communicate with the Philae lander after Friday. Here, lander manager Stefan Ulamec (left, in foreground) watches as data confirming the comet landing arrived Wednesday. European Space Agency hide caption

itoggle caption European Space Agency

Matthew McConaughey plays an astronaut explorer in Christopher Nolan's Interstellar. Paramount Pictures/Melinda Sue Gordon hide caption

itoggle caption Paramount Pictures/Melinda Sue Gordon

The Philae lander beamed back images showing one of its three feet on the surface of Comet 67P/Churyumov-Gerasimenko . This photo is compiled from two images; a wider version will be released later Thursday. ESA/Rosetta/Philae/CIVA hide caption

itoggle caption ESA/Rosetta/Philae/CIVA

The Philae lander took this photo of its descent onto comet 67P Wednesday, when it was about 3 kilometers from the surface. The landing site is seen with a resolution of about 3 meters per pixel. ESA/Rosetta/Philae/ROLIS hide caption

itoggle caption ESA/Rosetta/Philae/ROLIS