During asteroid search operations, NASA’s OSIRIS-REx spacecraft snapped several images of Jupiter and its Galilean moons: Io, Europa, Callisto, and Ganymede.
OSIRIS-REx obtained the image above with the PolyCam imager — the spacecraft’s longest range camera — on February 12, 2017. The distance to Jupiter is 418 million miles (673 million km).
The image was produced by taking two copies of the same image, adjusting the brightness of the gas giant separately from the significantly dimmer moons, and compositing them back together so that all four objects are visible in the same frame.
The image below was taken by OSIRIS-REx’s MapCam instrument on February 9. The distance to Jupiter is 419 million miles (675 million km).
With an exposure time of two seconds, this image renders Jupiter overexposed, but allows for enhanced detection of stars in the background.
OSIRIS-REx is currently on a two-year outbound journey to the asteroid Bennu.
On February 9, the spacecraft began its search for an enigmatic class of near-Earth objects known as Earth-Trojan asteroids.
According to NASA, OSIRIS-REx will spend almost two weeks searching for evidence of these small bodies.
Although astronomers have discovered thousands of Trojan asteroids accompanying other planets, only one Earth-Trojan has been identified to date, asteroid 2010 TK7.
They predict that there should be more Trojans sharing Earth’s orbit, but these small bodies are difficult to detect from our planet as they appear near the Sun on the Earth’s horizon.
OSIRIS-REx is currently traveling through Earth’s fourth Lagrange point, which is located 60 degrees ahead in Earth’s orbit around the Sun, about 90 million miles (150 million km) from our planet.
The mission team will use this opportunity to take multiple images of the area with the spacecraft’s MapCam camera in the hope of identifying Earth-Trojans in the region.
The study plan includes opportunities for the camera to image Jupiter, several galaxies, and the main belt asteroids 55 Pandora, 47 Aglaja and 12 Victoria.
On each observation day, MapCam will take 135 survey images that will be processed and examined by the mission’s imaging scientists at the University of Arizona.
Whether or not the mission team discovers any new asteroids, the search is a beneficial exercise.
The operations involved in searching for Earth-Trojan asteroids closely resemble those required to search for natural satellites and other potential hazards around Bennu when the spacecraft approaches its target in 2018. Being able to practice these mission-critical operations in advance will help the team reduce mission risk once the spacecraft arrives at Bennu.