OSIRIS-REx spacecraft photographs Earth and Moon

Ten days after Earth gravity assist, MapCam camera looks back on Earth-Moon system.

Laurel Kornfeld | Oct 17, 2017

On its way to the asteroid Bennu, from which it will send samples back to Earth for study, NASA's Origins, Spectral Interpretation, Resource Identification and Security Regolith Explorer (OSIRIS-REx) snapped a photo of the Earth-Moon system just 10 days after flying by our planet for a gravitational assist.

The composite image was taken by the probe's MapCam camera from a distance of approximately 3.2 million miles (5.1 million km), about 13 times the distance between the Earth and the Moon.

OSIRIS-REx launched in September 2016 to the 1,600-foot- (500-meter-) wide asteroid, where it will arrive in late 2018. After studying Bennu from orbit, it will land on the asteroid's surface and collect a minimum of 2.1 ounces (60 grams) of surface rock, which will then be returned to Earth five years later.

Never previously explored, Bennu frequently passes near the Earth.

Gravitational assists are common maneuvers used to speed up spacecraft and alter their trajectories without using fuel. OSIRIS-Rex's September 22 flight past Earth used the planet's gravity to slightly change its path in the direction of Bennu.

Immediately following the flyby, MapCam obtained a closeup of the whole planet from a distance of just 106,000 miles (170,000 km). The Pacific Ocean, Australia, and Baja, California, are visible in that color composite photo.

On October 2, MapCam imaged the Earth and Moon in a single frame.

In addition to MapCam, OSIRIS-Rex contains two other science cameras, a Canadian-built laser altimeter, a student-built dust experiment, a thermal emission spectrometer, a visible and infrared spectrometer, a student-built regolith X-ray imaging spectrometer, a sample acquisition mechanism, a sample return capsule, and a redundant navigation system.

Mission scientists used the Earth flyby as an opportunity to recalibrate some of the probe's instruments, which will study the asteroid's mineral and chemical makeup and search for organic molecules that make up the building blocks of life.

These advance searches will determine the site where the probe will land and collect samples.

Both the laser altimeter and the student-built dust instrument will not be turned on until the spacecraft reaches Bennu.

OSIRIS-REx's three cameras will begin photographing Bennu in August of next year and also search for moons and rings that could potentially pose a hazard to the spacecraft.

Detailed images of the asteroid will captured beginning in October 2018.