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Where is the Messenger Spacecraft right now?
The short answer to this question is: Messenger is on Mercury - where it crashed at the end of its mission on 30th April 2015.
The app above shows the trajectory of the Messenger Spacecraft and where it is right now. You can also wind the animation backwards in time to watch its launch and its successive flybys of the Earth, Venus and Mercury before entering Mercury Orbit in 2011.
Messenger Flight Path
Messenger was launched on the 3rd of August, 2004, with the aim of going into orbit around Mercury and studying this planet in more detail than ever before. The previous visit to the planet was the flyby of Mariner 4 a matter of 30 years before in 1975.
The idea of sending a probe to orbit Mercury had been evaluated before but it was considered too difficult/costly because of the problem of slowing the spacecraft down enough so that it matched the speed of Mercury closely enough. The problem is that as any craft falls into Mercury’s orbit it gains a lot of speed. In order to slow down in order to attain an orbit would require an enormous amount of fuel to decelerate. If Mercury had a thick atmosphere then the craft could possibly skim through the atmosphere to brake it, but Mercury's atmosphere is too thin for such a manoeuvre.
The problem was eventually solved by using a trajectory designed by Chen-wan Yen in 1985. This flight path involves using various flybys of the earth, Venus and Mercury so that gravitational sling shots (in reverse) would slow down the spacecraft sufficiently that much less fuel was required to achieve orbit.
The main manoeuvres are described here:
|Earth, Launch||3 August 2004|
|Earth, Flyby||2 August 2005|
|Venus, Flyby||24 October 2006|
|Venus, Flyby||5 June 2007|
|Mercury, Flyby||14 January 2008|
|Mercury, Flyby||6 October 2008|
|Mercury, Flyby||29 September 2009|
|Mercury, Orbit Achieved||18 March 2011|
|End of Mission||2015|
For an interesting 14 minute podcast about the Messenger Flight path and mission - visit the Physics Central website.
This NASA animation shows the spacecraft entering Mercury Orbit.
The orbit is very elongated with Messenger passing between 200km from the surface to 15,000km every 12 hours. This allows the spacecraft to cool off since it gets hot passing so close to such a hot planet.
Colour enhanced image of Mercury from Messenger. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Messenger has provided a huge amount of data and quite a few surprises. For a brief run down of discoveries, try this article.
Messenger ran out of fuel and eventually crashed into Mercury as its orbit decayed. The mission was extended by using cold helium gas to give an additional thrust to the craft which extended the mission by a or more month. Article. Messenger finally crashed on the 30th April 2015.