TESS exoplanet hunter tests camera as it swings by Moon
NASA's Transiting Exoplanet Survey Satellite (TESS) mission took its first image during a dramatic lunar flyby this week. On May 17, the next-generation planet hunter passed within 5,000 miles (8,000 km) of the Moon to execute a slingshot maneuver that hurled it towards its final orbit, where it will spend at least two years making a full-sky survey in search of planets beyond our Solar System.
Launched on April 18 from Cape Canaveral Air Force Station atop a SpaceX Falcon 9 rocket, TESS is the successor to the Kepler Space Telescope and is tasked with examining 200,000 of the brightest stars in our galaxy spread over an area that is 400 times greater than that observed by Kepler.
Its four cameras are much more advanced by those carried by Kepler and as part of the shakedown cruise while the spacecraft heads for its final science orbit, mission control ordered TESS to make a two-second exposure of an area in the constellation of Centaurus that includes 200,000 stars as well as the Coalsack nebula and the bright star Beta Centauri (lower left edge of the image). In June, the probe will return a science quality or "first light" image to show off its capabilities.
Until now, the spacecraft has been carrying out maneuvers to increase its elliptical orbit around the Earth, then Thursday's flypast sent it into a much larger orbit. When it completes one final thruster burn on May 30, the TESS will be in a lunar resonant orbit. That is, it will be in an elliptical orbit between 108,000 km (67,000 mi) and 375,000 km (233,000 mi) that circles the Earth every 13.7 days with an inclination of 37 degrees to the Moon's orbit.
The reason for this orbit is to make sure that TESS is always 90 degrees out of phase with the Moon, so the latter's gravitational field can't disrupt the spacecraft's trajectory for decades to come. In addition, this orbit will give TESS a clear view of the whole sky, allow it to maintain its temperature, and keeps it well out of the radioactive Van Allen belts.
The video below discusses the flyby maneuver.