After a journey lasting more than 10 years, a spacecraft is just days away from softly landing a robotic probe on a comet.
The European Space Agency's Rosetta spacecraft is scheduled to land the probe, dubbed Philae, on comet 67P/Churyumov-Gerasimenko on Wednesday at 10:35 a.m. ET. The probe is supposed to land on the comet's nucleus and then track the cosmic object and send data back to Earth as the comet continues on its path, hurtling past the sun.
NASA noted that if all goes as planned, it will be the first time a spacecraft makes a soft landing on a comet.
The Philae lander is expected to take the first photos ever snapped on a comet's surface, according to NASA. It's also expected to study, up close, how the object changes as it approaches the sun and drill into the comet to study its composition.
Scientists from both the European Space Agency and NASA are hopeful the probe can remain working on the comet's surface for about two and a half days.
The Rosetta spacecraft, however, should have a much longer mission, remaining in orbit around the comet through next year, studying the comet's advance and then its departure from its closest approach to the sun.
The spacecraft already has taken images of the comet, showing steep ravines, sharp cliffs and numerous boulders. Some of the photos have been taken from as close as 18.6 miles away from it.
The lander and the Rosetta spacecraft are both carrying scientific instruments to carry out observations, imaging and geological studies on the comet.
NASA, working together with the European Space Agency, provided three of the 16 instruments on board the Rosetta orbiter. The NASA instruments include a microwave instrument designed to study how gas and dust peel off the comet's surface to form its tail, along with an ultraviolet spectrometer, called Alice, which can analyze the gases in the comet's coma and tail.
The U.S. space agency also built the spacecraft's Ion and Electron Sensor, which is one part of a suite of five instruments to study the comet's plasma environment and the charged particles in the sun's outer atmosphere as they interact with the comet's gases, according to NASA.
Scientists are eager to get information about the comet since comets are thought to hold critical clues to the birth of our solar system. Particles from the very beginnings of the solar system have been frozen inside the comets; NASA has theorized that the particles are the building blocks of our own system.
Comets also are thought to have helped provide Earth with water and other necessary ingredients for life as we know it.
The European Space Agency launched Rosetta, and its onboard probe, in March 2004. It spent 957 days in a scheduled hibernation as it flew through space toward the comet.
Scientists woke the spacecraft up in January as it began its approach to the comet. Rosetta rendezvoused with the comet in August and maneuvered into orbit around it.