AT 00:45 GMT on 18 March 2011, NASA’s MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) spacecraft became the first probe to enter into the planet Mercury’s orbit.
MESSENGER was launched from Cape Canaveral, Florida, back on 3 August 2004. To finally get into a position to be captured by the smallest planet’s gravity, MESSENGER had to complete no less than six planetary flybys: one of Earth, two of Venus and three of Mercury itself.
During its mission from here on in, MESSENGER will orbit Mercury approx. 730 times, and will capture some spectacular pictures of the planet with orbits on average just 36 million miles (58 million Km) from the Sun.
Because of its close proximity to the Sun, Mercury’s surface temperature can reach over 427˚C, which is hot enough to melt lead. So to cope with these extreme mercury levels (couldn’t resist) MESSENGER has had special heat deflecting shields attached to it. But that’s just when it is facing the Sun. The night side of Mercury has to suffer temperatures of a chilling -183˚C.
MESSENGER is only the second spacecraft to visit the innermost planet. Back in 1974/5, Mariner 10 mapped around 45% of Mercury’s surface. It is now MESSENGER’s job to map the rest. Hopefully we’ll be getting some more great images of Mercury like the one below, which MESSENGER took on a previous flyby.
Meanwhile, deep in the Solar System another NASA probe reached an important milestone. The New Horizons spacecraft crossed the orbit of the planet Uranus on the very same day MESSENGER entered Mercury’s orbit at 22:00 GMT. But unfortunately no pictures could be taken because Uranus was nearly 3.9 billion Km away at the time.
New Horizons is just over five years and two months into its mission to the dwarf planet Pluto, and will be the first probe to reach the ex-planet. On its long voyage across the Solar System, New Horizons crossed Mars’s orbit on 7 April 2006, got a gravitational assist from Jupiter on 28 February 2007 (and took some awesome pictures of the gas-giant and its moons to boot), passed Saturn’s orbit on 8 June 2008, and reached half-distance on 29 December 2009. New Horizons will cross Neptune’s orbit on 24 August 2014.
Pluto will finally be visited on 14 July 2015 at 11:47 UTC at a distance of 13,695 Km. 14 minutes later, New Horizons will flyby Pluto’s three moons: Charon, Hydra and Nix. The probe will then do as Pioneers 10 and 11 and Voyagers 1 and 2 did and leave the Solar System. This is expected to happen in 2029, 99 years after Pluto was discovered.
A day later (19 March) it was the Moon that made the headlines as it made its closest approach to Earth in almost 20 years. The Supermoon appeared about 14% bigger and up to 30% brighter than a normal full moon in the cleat Saturday night sky.
I for one wasn’t going to miss it, and went up into my garden with my plucky digital camera. I go a few pictures, but they are far off being world class. The one below is the one I am most proud of. I think I set it to black and white, and was quite stunned to find that I had captured some of the detail on the lunar surface.
And finally, today (23 March 2011) is the tenth anniversary of the deorbit of the Russian space station Mir.
After years of service, it became unfeasible for the Russians to fund both it and the International Space Station (ISS). So Mir was brought back down to Earth over Fiji in a fire ball, which as an eight year-old boy I found rather exciting.