After comet Siding Spring made a close flyby past Mars on Sunday, one of NASA's orbiters and a robotic rover captured images of it -- and they've already beamed them back to Earth.
"It's excitingly fortunate that this comet came so close to Mars to give us a chance to study it with the instruments we're using to study Mars," said Opportunity science team member Mark Lemmon. "The views from Mars rovers, in particular, give us a human perspective, because they are about as sensitive to light as our eyes would be."
Scientists pointed the Mars rover Opportunity's panoramic camera (Pancam) at the comet, also known as C/2013 A1, capturing images of the flyby. The image that the rover captured is from a 50-second exposure taken about two-and-a-half hours before the closest approach of the comet's nucleus to Mars, according to the space agency.
Opportunity, which has been working on Mars since January 2004, was unable to get images of the comet during its closest approach because the Martian dawn was too bright. The rover, working on the Martian surface, wasn't the only NASA machine to capture images and data, however.
NASA's Mars Reconnaissance Orbiter, which entered Martian orbit on March 10, 2006, used its High Resolution Imaging Science Experiment camera to grab images as the comet hurtled past.
The images the orbiter provided are the highest-resolution views ever acquired of a comet coming from the Oort Cloud, which is at the fringes of the solar system. The comet's Mars flyby provided spacecraft orbiting the Red Planet an opportunity to investigate it from close range, giving scientists information about its nucleus.
NASA has not yet released any details about what details its gleaned about the comet's makeup.
While NASA's rovers Opportunity and Curiosity were protected by the Martian atmosphere, the space agency's three orbiters -- the Mars Odyssey, the Mars Reconnaissance Orbiter and the Mars Atmosphere and Volatile Evolution orbiter -- didn't have that protection. To keep them from being damaged by debris from the comet's nucleus, NASA engineers positioned the orbiters on the far side of the planet during the comet's approach.
That didn't keep them from being able to grab images and data about it as it passed by just 87,000 miles away -- the equivalent of about one-third the distance between Earth and its moon.
Scientists hope to use the observations to gain new clues about comets and our solar system.
The Siding Spring comet is made up of a giant swarm of icy objects believed to be material left over from the formation of the solar system.