The MESSENGER spacecraft left Earth in early August 2004, is just days away from the end of its mission

Apr 28, 2015 08:50 GMT  ·  By

This coming Thursday, April 30, NASA scientists will say goodbye to the MESSENGER probe, launched in early August 2004 as part of the agency’s second mission to Mercury, after the Mariner 10's flybys of the planet in 1974 and 1975. 

The probe, whose name stands for MErcury Surface, Space ENvironment, GEochemistry, and Ranging, is all out of fuel. This means that it can no longer keep itself in flight and will soon plunge to its doom.

Mission scientists expect that, come April 30, the MESSENGER spacecraft will crash into Mercury at a speed of nearly 4 kilometers per second (approximately 2.5 miles per second). The not-so-smooth landing will mark the end of its mission.

Interestingly, the probe managed to keep itself in Mercury's orbit for much longer than anticipated. Thus, it's primary quest ended in 2012 and scientists have since extended its mission on two occasions.

Why NASA scientists launched this mission

In a recent interview with Nature, mission scientist Sean Solomon explained that the MESSENGER mission to Mercury was launched in an attempt to level the field and not leave this planet out of the space exploration game.

“We had multiple missions to Mars and the Moon, and only Mariner 10 had gone to Mercury. It flew by three times [twice in 1974 and once in 1975], and its images gave us our first ideas about Mercury’s geological history. But there was so much unanswered,” Sean Solomon said.

Having left Earth in early August 2004, the MESSENGER spacecraft completed a total of three flybys of Mercury before having finally settled in its orbit in March 2011.

As part of its mission, the probe studied Mercury's chemical makeup, its geology and its magnetic field. One of its best finds was deposits of ice water resting at the planet's poles under a layer of organic-rich material similar to the one found in some meteorites and comets.

The probe also found that some of the geological features on Mercury are younger than others. This means that, rather than be frozen in time, the planet has several times changed over the years.  

A few weeks back, scientists released a series of images obtained by the MESSENGER spacecraft from an altitude of merely 15 kilometers (roughly 9 miles). The images, showing impact craters and cracks in the ground visible on the surface of Mercury, are available in the gallery below.

Another Mercury mission will soon follow

Come 2017, the European Space Agency will launch its own Mercury mission, which will see not one but two probes being sent to this planet. Should all go well, the probes will reach Mercury in 2024.

Commenting on this upcoming Mercury mission, NASA's Sean Solomon pointed out, “They have a dual spacecraft with many more instruments than us. The different viewing geometry, the slightly different mix of instruments and the fact that they have two spacecraft will give them opportunities.”

NASA images reveal Mercury's geology (6 Images)

Artist's depiction of the MESSENGER probe and Mercury
Craters containing iceThe wall of a volcanic vent
+3more