June 17, 2008
A Great Year for NASA
2008 has turned out to be a great year for NASA _ one of the best in its 40-plus year history. And the last couple of weeks have been especially impressive. Let's take a look at what NASA has accomplished.
One of the most amazing feats was the successful touchdown of the Mars Phoenix Lander near the north pole of Mars. This is the first soft landing on Mars in 30 years. When the spacecraft turned on its cameras and gave us our first look, the setting appeared absolutely desolate. But the mission is focused less on what we see, and more on what's beneath the surface.
NASA scientists hope to find a giant block of ice at the north pole. If there is ice on Mars and it is close to the surface, it might make a Mars mission easier. The ice could provide fuel, drinking water, irrigation and maybe a raw ingredient for construction. And obviously if there was once lots of water on Mars, and if some of it remains, there is hope that some type of life might have appeared on Mars in the distant past.
So how will the lander figure out whether or not there is ice on Mars? It has three different instruments that can look at the soil in incredible detail. The first instrument is the TEGA, or the Thermal and Evolved Gas Analyzer. TEGA starts with a small sample of soil that the lander's robotic arm digs from the surface. TEGA slowly heats the sample, looking at the amount of energy it takes during the heating process. The sample's temperature eventually rises as high as 1,800 degrees F. Meanwhile, different gases are boiling off the sample, and they get analyzed by a tool called a mass spectrometer. Think of a mass spectrometer as a very very sensitive nose that can detect individual chemicals in incredibly dilute quantities and report back to Earth.
There is also a microscope and a wet lab. The microscope lets scientists on earth look at soil grains down to the atomic level. The wet lab lets scientists measure the acidity and conductivity of the soil, and also check for different kinds of common soil chemicals. After running all these tests, scientists will have a detailed analysis of Martian soil, and will know how much ice it contains.
While the Phoenix lander has been getting a huge amount of press, another mission lifted off recently with much less fanfare. It is called GLAST, or the Gamma-ray Large Area Space Telescope. It's an orbiting telescope in the same way that the Hubble Space Telescope is an orbiting telescope. But instead of looking at light like the Hubble does, GLAST looks at gamma rays.
The interesting thing about gamma rays is their source. Gamma rays come from some of the most energetic events in the universe. For example, when a star explodes in a supernova, it usually produces gamma rays. When black holes swallow stars, the same thing can happen. GLAST will let scientists better understand what is going on, and why.
NASA has also been adding to the International Space Station, and the June shuttle flight played an important role. The STS-124 mission took up the biggest piece of the space station so far _ a compartment as large as a Greyhound bus. It's part of the Japanese science lab, and it will allow scientists to perform a wide range of experiments in areas ranging from biology to materials science.
One of the interesting things about the Japanese lab is that it has both the huge pressurized section for humans, as well as a "terrace" that is out in the open vacuum, completely exposed to the space environment. A robot arm and an airlock will let scientists manipulate the experiments outside.
The space station now weighs more than 600,000 pounds and has an internal volume of 11,000 cubic feet. That makes it about as big as a 1,400 square foot house on Earth. Seven more missions over the next two years will complete the space station.
And the year isn't but half over. NASA is planning a huge mission in October to service and repair the Hubble telescope one more time. There are two more construction flights to the ISS planned in November and December. Several other smaller satellite missions will launch as well.