Just about every kind of scientific instrument has been put on a satellite.
The first scientific instruments sent into space were launched on Feb. 1, 1958, on the Explorer I satellite. In the intervening decades, hundreds of space missions have carried thousands of other scientific instruments into space. The types of instruments used in space are as varied as those used on Earth. A quick review will illustrate the variety.
Explorer I: Space Science is Born
The first U.S. satellite was the result of a frantic rush to demonstrate that American technology was second to none. The Soviet Union had launched Sputnik in October 1957, and the U.S. was madly trying to catch up. Scientists had known that the U.S. would launch satellites sooner or later, and they had built and tested instruments to make interesting measurements. What turned out to be the first significant instrument was essentially a geiger counter --- a device that counted energetic particles. Explorer I provided unexpected measurements, so scientist James Van Allen modified his instrument for Explorer III and detected bands above the Earth packed with high energy particles, regions now called the "Van Allen Belts."
Energetic Particle Detectors
Energetic particle measurements provided evidence of water on the moon.
On Earth, the atmosphere shields the surface from high energy particles, so it was very difficult for scientists to predict what kinds of particles would exist. Just about every satellite that goes to a yet-unexplored location will have some kind of energetic particle detector looking for particles ejected from the sun, "cosmic rays" produced elsewhere in the universe, and products of radioactive decay. For example, the neutron spectrometer on the Lunar Prospector mission is an energetic particle detector --- and that's the one that provided evidence of water near the surface of the moon.
Chemical Analysis
Scientific instruments on the Mars rovers continue to provide information about the red planet.
For space probes that land on a planet, one of the obvious questions becomes, "What is this planet made of?" There is a wide variety of instruments designed to answer that question. One type, first used on the Surveyor lunar exploration program in the late 1960s, is called the "alpha scattering surface analyzer." It looked at the reactions of a sample to radioactive particles and measured elements in the sample. A similar instrument is still in use on the surface of Mars.
Cameras, Cameras, Everywhere
Little can match the emotional impact of a picture sent from a distant world.
Sometimes the most amazing measurements are so abstract that it's difficult to understand their importance. There is no escaping the emotional impact of a picture. Cameras and telescopes have provided images of distant galaxies, swirling clouds on other planets, volcanoes or frozen wastes on distant moons, dramatic cometary crashes --- these images are noteworthy for their beauty, yes, but also for the information they provide about the scientific rules by which our universe operates.
Biology
People evolved in a very benign environment. On Earth there is oxygen at decent pressure, temperatures not too difficult to deal with, and another benefit often taken for granted: gravity. Wherever people have ventured into space, part of the mission is to evaluate the effect of the unusual environment on the human organism. The health of every astronaut is frequently --- if not continuously --- monitored. Other biological experiments are designed to look for other forms of life. For example, the "labeled release" experiment on the Viking Mission was designed to look for chemical signals indicative of life. It found positive results, but most scientists now believe this was the result of unanticipated chemical reactions.
Only an Introduction
An article that attempted to provide a comprehensive list of every type of scientific instrument ever flown would be many pages long. There are just about as many different kinds of scientific instruments in space as there are on Earth. There are laser rangefinders that map clouds and planetary surfaces, optical spectrometers that measure the wavelength of light emitted or absorbed by a sample, magnetometers to measure magnetic field strength, even grinding wheels and shovels designed to expose soil on other bodies and investigate the way it moves. Space scientists are very interested in spreading the results of their work, so a lot of information is available on the Internet (see Resources).
Tags: into space, scientific instruments, about every, designed look, emotional impact
