In early 2013, NASA had serious concerns about the ability the Kepler space telescope to continue his hunt for exoplanets. To locate these stars by the planetary transit method, we must point the telescope precisely, which requires at least three reaction wheels, flywheels used in probes and satellites to change their angular momentum without consuming fuel .
In fact, by rotating these flying by electric motors, one can change the intrinsic angular momentum to a satellite, for conservation of total angular momentum, must rotate in the opposite direction, according to a new axis. Cella allows to change the orientation of a spacecraft to properly point a star with a telescope or a satellite dish, for example.
As shown in this video, the gravitational field of a massive exoplanet nomadic light rays the star to which it passes and acts as a lens temporarily increasing its brightness ( brightness ). Kepler is able to observe a microlensing effect of this kind. © NASA’s Ames Research Center YouTube
Kepler was equipped with four wheels, for safety. When two of them dropped, the question of the continuation of the mission arose. But the engineers of NASA are smart and work program, as amended, has been continued (see previous article).
Unfortunately, last week, these same engineers during a routine renewal of contact with Kepler discovered that the instrument was placed in “Emergency mode” (EM). Kepler has five operating modes (which affect the operations performed on board and opportunities for maneuvers): one for observation, both for maintenance and two trigger in case of failure. The EM mode is the worst because the internal mass memory (SSD) is cleared. The latest observation data, awaiting download to Earth, so have disappeared (the interested reader, and English, will find explanations on the technical manual Kepler Instrument Handbook , especially page 85) . Moreover, the statement said NASA, the vehicle uses more fuel, which will therefore reduce its life time.
The mission managers ignore the reason for the malfunction and even if Kepler will be again be used. Just before the crash, astronomers were about to use it to detect exoplanets nomads in the Milky Way by microlensing effect.
Kepler has enabled us to discover over a thousand exoplanets (1,041 were validated) and spotted thousands more who are waiting to see their existence confirmed by ground-based observations.
In artist’s impression, hunting Kepler exoplanets within the Milky Way. The instrument uses the planetary transit method, consisting in identifying the low drop in brightness of a star when a planet passes in front. Launched in 2009 for a mission of 3½ years, Kepler saw his mission prollongée 2016. The telescope has spotted about 5,000 exoplanets, of which slightly more than a thousand were confirmed by . observations from the ground © Nasa
Kepler exoplanet hunters is down again – Photo 1
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