The NASA Transit Exoplanet Survey Satellite, which was near Earth for the first time since its launch a week ago, fired its engines early Wednesday and began its orbit to the Moon for one May 17 Gravity Assistance Maneuver to Amplify (19659003) The spacecraft's engines fired on early Thursday to bring the outermost point of the TESS orbit around Earth closer to the Moon. The maneuver was timed when TESS reached its first perigee – the lowest point of its elongated orbit – since April 18, from Cape Canaveral aboard a SpaceX Falcon 9 rocket.
The Falcon 9 launcher deposited TESS in an elliptical orbit that stretched 170,000 miles (270,000 kilometers) from Earth. TESS briefly fired its thrusters on Saturday when it reached the outermost point or apogee of its original orbit to increase its perigee from about 150 miles to about 1,400 miles (2,250 kilometers).
The next maneuver was conducted early Wednesday. According to the US military, the TESS apogee was positioned at approximately 220,000 miles (354,000 kilometers), more than 90 percent of the Moon's orbit's distance.
The ignition of the engine on Wednesday was the second of six maneuvers to send TESS to its final operational orbit. Another fire will occur next week as TESS reaches its new peak, followed by two more perigee maneuvers that fine-tune the satellite's trajectory and prepare for a moon flight on May 17.
The next month's moon flight – At a distance of about 8000 kilometers from the moon, TESS will be placed in orbit far beyond the lunar range, and a final large engine bombardment will reduce the height of the apogee in June.
Until June 17, TESS will be in its last science orbit and ready to begin the planet hunt.
TESS will end in an orbit that resonates with the moon and is between 67,000 miles (108,000 kilometers) and 233,000 miles (376,000 kilometers) from Earth. In this orbit, TESS will make a lap around the earth every 13.7 days, about half the time it takes for the Moon to orbit the Earth.
Since its launch on April 18, ground control equipment at Orbital ATK in Dulles, Virginia, which built the spacecraft, has turned on key components on the satellite, including reaction wheels and star trackers that keep TESS in space. On Wednesday, engineers sent orders to turn on the satellite's Ka-band transmitter, which routes signals through a high-gain antenna needed to send full-frame images of TESS's four 16.8-megapixel science cameras to Earth ,
Controllers planned to begin activating the cameras as early as Thursday, starting with a few weeks of calibrations and checkouts to ensure that MIT-built imagers are scientific observations.
Each of the four cameras is equipped with four red-sensitive CCD detectors, which transit in front of their host stars. The cameras will search starlight for short dips to find the planets, and sophisticated software algorithms will allow astronomers to scan wide swaths of the sky as images are doubled to Earth.
During Tess's Two-Year Mission MIT's built-in cameras will capture more than 85 percent of the sky and will spot close to 200,000 preselected bright stars, including some 6,000 stars visible to the naked eye in the night sky.
Read Our Earlier History for Mission Details
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