In a brilliant nighttime launch, a Delta II rocket from United Launch Alliance (ULA) blazed into a black sky over Cape Canaveral Air Force Station, Fla., to place the Kepler planet-hunting space telescope into precisely the correct position.
ULA is a joint venture of The Boeing Co. [BA] and Lockheed Martin Corp. [LMT], and the Delta II is a medium-class Boeing- designed lifter, a three-stage rocket with six strap-on boosters.
It was a happy moment for NASA to see its extremely valuable Kepler spacecraft program, the product of years of effort and $591 million in funding, become a huge success story.
That unqualified win came after NASA just last month lost its Orbiting Carbon Observatory (OCO) satellite that was years in the making, when an Orbital Sciences Corp. [ORB] Taurus XL rocket launched well, but a nosecone fairing protecting the satellite during launch failed to separate. The OCO wound up plunging to the bottom of the sea near Antarctica. (Please see Space & Missile Defense Report, Monday, March 2, 2008.)
Experts checked to ensure that no similar fate would occur in the Kepler launch. And it didn’t.
Instead, right on schedule early Saturday morning, Kepler separated cleanly at 61 minutes, 49 seconds after launch. Omar Baez, NASA launch director and launch manager at Kennedy Space Center, said the launch and countdown appeared nominal, with the only tiny glitch being a hangup in getting ground-station data from Australia back to Florida. There also was a minor gyroscope issue that was never a real problem.
After a two-month checkout and calibration period, Kepler will begin hunting for a planet like Earth out in the void of space, according to Jim Fanson, Kepler project manager at the Jet Propulsion Laboratory.
Kepler will focus on just 100,000 stars in the Milky Way galaxy, attempting to detect Earth-like planets orbiting any of those stars, according to Patti Boyd, a Kepler expert who spoke in a NASA press briefing with Baez.
Such “exoplanets” outside the solar system including the sun and Earth could be difficult to find, and NASA experts said they don’t know whether there will be many Earth-like planets circling other stars, or perhaps very few, or none found, she said.
While 100,000 stars may sound like a huge number, it actually is tiny. There can be more than 100 billion stars in a galaxy.
Kepler will watch those 100,000 stars intently for three years or more, to see whether there is a slight tell-tale dimming that would signal a planet is transiting across the face of its star, passing between the star and Kepler.
While some 340 exoplanets have been discovered thus far, many are huge, or blistering hot, or freezing cold. “We’ve yet to discover a true analog to Earth,” Boyd said.
Kepler is looking for a rock planet such as Earth, rather than a gas giant, and the sought-after planet will be in a moderate zone, not so close to its star that the planet is scorching hot, but also not so far from the star that the planet is freezing cold. In other words, Kepler wants to find a planet that has a moderate temperature where liquid water could be present, because “we believe that water is necessary” for life to exist, at least life forms such as exist on Earth, Boyd said.
It’s possible Kepler could miss many Earth-like planets, according to Natalie Batalha, co-investigator at San Jose State University. She noted that planets around a star tend to move in a single plane around the star, like marbles on a plate.
What is perfect for Kepler is if the planetary plane of a star and its planets is tilted so Kepler views that plane edge-on: in that case, any planet in that system crosses directly between Kepler and the star, and is easier to spot. On the other hand, with a different tilt to the planetary plane, only a planet or two closest to the star might be visible. And if the plane is at right angles to Kepler, none of the planets will be visible for Kepler to spot transiting across the star and blocking a tiny bit of its light.
Where will all this lead? If Kepler finds some Earth-like planets, it won’t know whether they have atmospheres and water.
But Kepler will prove that it’s worth taking a closer look at some planets, and that closer look would involve serious money, perhaps $5 billion to $8 billion for a very large telescope to probe the mysteries of those orbs.
If the mission does find Earth-sized planets in the habitable zones of stars, it should find them first around stars that are smaller than the sun. This is because the habitable zone is closer for small stars; planets circling in this region would take less time to complete one lap and, theoretically, less time for Kepler to find them and for other ground-telescopes to confirm their existence. Any Earth-size planets orbiting in the habitable zones of stars like the sun — the true Earth analogs — would take at least three years to be confirmed.
Kepler is a NASA Discovery mission. Ames Research Center is the home organization of the science principal investigator and is responsible for the ground system development, mission operations and science data analysis.
The Jet Propulsion Laboratory in Pasadena, Calif., manages the Kepler mission development. Ball Aerospace & Technologies Corp. of Boulder, Colo., is responsible for developing the Kepler flight system and supporting mission operations. NASA’s Launch Services Program at Kennedy Space Center, Fla., manages the launch service including payload integration and certifying the Delta II launch vehicle for NASA’s use.
For more information about the Kepler mission, visit: http://www.nasa.gov/kepler