A few days ago I was reading a news story about a new comet that’s bound to be rather awesome this fall, C/2012 S1 (ISON). (C means comet, 2012 is when it was discovered, and S1 means it was the first comet discovered in the second half of September. ISON is the name of the observatory that discovered it.) The story was about all of NASA’s probes in the solar system that were going to help observe it. I was rather amazed by what all we have out there drifting around. Since most people probably aren’t too familiar with this little Earthling fleet, here’s the rundown, starting from the sun and working our way out.
MESSENGER
It’s amazingly hard to get to Mercury. Deep down in the Sun’s gravity well, you get going pretty darn fast. That’s why MESSENGER (short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging) had to do an Earth flyby (watch the video…. it’s awesome!), two Venus flybys, and three Mercury flybys before just barely squeezing itself into an elongated orbit. Six and a half years and four billion miles later, it safely began science observations. Discoveries include the fact that Mercury actually has ice in some shaded craters at its poles (despite the fact that some parts of the planet can reach 800 degrees) and the fact that Mercury’s core is nearly the size of the planet itself, indicating that perhaps a huge collision once blasted off most of the mantle.
Venus Express
This probe is actually the European Space Agency’s. NASA doesn’t have a Venus orbiter at the moment. I personally find Venus a bit boring- yes, it’s kind of awesome with its sulfuric acid rain and all, but there really isn’t much there. Venus Express has done some cool experiments, though, such as looking back at Earth and taking pictures to see what an habitable planet’s signature would look like from far away.
Lunar Reconnaissance Orbiter
The Lunar Reconnaissance Orbiter was launched in 2009 and has undergone the process of mapping most of the lunar surface. From its only 50km high orbit, it can spot things as small as tracks made by Apollo astronauts. It has also discovered ice in lunar craters, potentially enough for humans to use as fuel, a source of oxygen, and water in the future.
Mars Odyssy, Mars Express, Mars Reconnaissance Orbiter, Curiosity, Opportunity
Mars Reconnaissance Orbiter
Mars Odyssy, Express, and Reconnaissance Orbiter are all orbiters that help take pictures of Mars, send data back from the two rovers (Curiosity and Opportunity), and conduct other scientific studies, such as measuring Mars’ magnetic field and atmospheric composition.
Curiosity Rover
The two rovers we have are some of the most sophisticated pieces of hardware we’ve ever sent to space. Opportunity has now been on Mars for about 10 years and is still limping along (though slowly… and only in reverse.) It has discovered all kinds of things, including the first solid evidence of former liquid water on Mars. Curiosity is MUCH larger, nearly the size of a car, and nuclear-powered.
Juno
Juno is one of NASA’s most recent missions, sent to Jupiter to study its atmosphere, magnetic field and composition. Despite being such a large and easily observable planet, we don’t quite know what it’s made of on the inside. Juno is on schedule to arrive in 2016.
Cassini-Huygens
Cassini has been one of NASA’s most successful missions ever. Launched in 1997, it has now been orbiting Saturn for 9 years. Huygens was a small probe that Cassini dropped onto Saturn’s moon Titan, the only small body in the solar system to possess an appreciable atmosphere.
View from Huygens at 16 kilometers up
It spied lakes, rivers, and other landforms only thought to exist on Earth during descent before landing in a mud puddle. (Rivers and a shoreline are visible in the picture at left.) However, instead of water, methane and ethane cover the planet.
New Horizons
This rocket, specifically.
New Horizons will be the first spacecraft to ever visit Pluto in about two years. It’s 2/3 of the way now and speeding away faster than any other spacecraft has. It was launched into a direct earth and solar escape trajectory, meaning that the rocket carrying it was not only powerful enough to take it past our orbit, but out of the solar system for good. After Pluto, New Horizons will look for other dwarf planets to explore, then fly out of our solar system.
Voyager 1 & 2
Voyager 1 and 2 were launched in the 1970s and gave some of the first detailed observations of the outer giant planets- all four of them. Due to a wonderful alignment, Voyager 2 managed to visit Jupiter, Saturn, Uranus, Neptune, and could have gone to Pluto, too, but opted for better observations of Titan instead. They still offer some of the best data about Uranus and Neptune, and are somehow still working. Despite 35 years of traveling through the cold and darkness of space, both are still transmitting data from outside of our solar system. In fact, today Voyager 1 just officially left our home solar system, becoming Humanity’s first interstellar spacecraft.
The Pale Blue Dot image of Earth was taken by Voyager 1 from 3.7 billion miles away. Earth is the pale blue dot in the middle of the rightmost diffraction ray.