It’s the most powerful telescope NASA has ever launched.
The primary mirror undergoes inspection.
The Kepler spacecraft, set for launch from Cape Canaveral today (March 6), is taking aim at about 100,000 stars in a section of the galaxy, hoping to detect planets that might resemble Earth in size and temperature.
The craft, built by Colorado-based Ball Aerospace, is packing a camera that dwarfs the power of the Hubble. It has an aperture of about 1 meter and boasts a 55-inch mirror and 95 megapixels of imaging capacity, using 42 CCDs (2200x1024 each), made by e2v.
Kepler will follow Earth in its solar orbit. The plan is to find planets as they pass in front of their suns and affect the light that reaches Kepler—a tactic NASA has likened to detecting a flea passing in front of an auto headlight, or measuring a difference in brightness of about 20 parts per million.
By measuring the period of orbit around the sun (fast for planets close to their stars, slow for planets further away), scientists can take a guess at the planets' temperatures.
“I call it our planetary census taker,” Jon Morse, director of NASA’s Astrophysics Division, said at a briefing on the project. “It may fundamentally alter humanities’ view of itself.”
Once a month, the unit will spend about a day sending data back to Earth at about 4 Mbps over K-Band. The data will be received at sites in California, Spain and Australia. After that, more work begins as the complex data gets processed, ultimately for release to the public so the scientific community and even amateurs can take closer looks.
The first “exoplanet,” or planet outside our solar system, was only discovered in 1995, and only about 300 have been identified since. Most tend toward the giant, Jupiter-like planets, as they are easier to spot. But NASA hopes Kepler will identify thousands of new exoplanets, including dozens or even hundreds of objects with Earth-like characteristics.
“Kepler may not find ET, but it’s hoping to find ET’s home,” said William Borucki, principal investigator for Kepler science, based at NASA's Ames Research Center, Moffett Field, Calif.
The project is slated to last three-and-a-half years at a cost of less than $600 million, although NASA said the craft is designed to operate for six years or longer.