MESSENGER will live
The team’s engineers have decided to make use of the gas pressurization in the propulsion system of the spacecraft to allow the MESSENGER spacecraft to extend by one month its study on the closest planet to our star.
MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft was launched on August 3, 2004, and entered orbit about Mercury on March 17, 2011 (March 18, 2011 UTC), to begin a yearlong study of its target planet.
MESSENGER’s first extended mission began on March 18, 2012, and ended one year later. MESSENGER is now in a second extended mission, which is scheduled to conclude in March 2015. Dr. Sean C. Solomon, the Director of Columbia University’s Lamont-Doherty Earth Observatory, leads the mission as Principal Investigator. The Johns Hopkins University Applied Physics Laboratory built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA. There are only a few days that we gave farewell to the European probe Venus Express precipitated on the surface of the planet that has explored for ten years, now exhausted all forms of energy. And the same fate is awaiting NASA’s MESSENGER, which in March next year will have consumed all the fuel available and will make its mark on the surface of Mercury. But we know, in scientific research, space exploration, every second gained can be very valuable to learn about celestial bodies that man studies using probes. And so the team’s engineers have decided to make use of the gas pressurization in the propulsion system of the spacecraft to allow the MESSENGER spacecraft to extend by one month its study on the closest planet to our star. “MESSENGER has virtually exhausted its liquid propellant preventing new maneuvers to keep it alive longer, changing the orbit” explains the system engineer of the mission, Dan O’Shaughnessy, of the Johns Hopkins University Applied Physics Laboratory. “However, the helium gas used to pressurize the propellant tanks of the probe that could be used to continue to make small adjustments to the trajectory.”
This gas is certainly less efficient, and more or the motors are not optimized for its use, but it is still as effective as liquid propellant to change the trajectory of the spacecraft. Thanks to this ploy MESSENGER will spend more time exploring Mercury from close range. Since last summer, in fact, has started an observation campaign at low altitude to acquire high resolution images of Mercury. “During the additional period of operation, up to four weeks, the probe will measure the variations of the internal magnetic field of Mercury in horizontal scales shorter than in the past,” adds Haje Korth, head of the magnetometer on the spacecraft. Currently, the MESSENGER spacecraft is in orbit at 101 km altitude. The next correction will take place January 21 next, when it drops to 25 km altitude, to be pushed back up to 80 km.