By 1994, Borucki and his team had closed in on the algorithms necessary to make sense of CCD data, and the project, nicknamed FRESIP (Frequency of Earth-Sized Inner Planets), was ready to compete for a NASA Discovery mission. (Discovery missions were to reflect NASA chief Dan Goldin’s vision of cheaper and more tightly focused projects that could be launched 36 months from selection and cost no more than $299 million from design through launch and data analysis.)
Though NASA liked the concept of FRESIP, it was shot down by reviewers, who said the effort would cost far more than the team anticipated. Several team members believed NASA overestimated costs by simply scaling down the expenses of bigger, more inherently complex missions. “We were put in the same box as the large high-precision astronomical telescopes,” says Larry Webster, Kepler’s project manager and an old NASA hand who has worked closely with Borucki for the past decade.
Two years later, Borucki and his team were ready again. This time they had three groups check out their costing scheme, but reviewers said that the system, renamed Kepler to distance it from FRESIP’s price tag flap, didn’t seem capable of imaging the promised tens of thousands of stars. So the team built a camera with a CCD and began testing it in October 1997 at Lick Observatory in the nearby mountains. Lacking funds to hire anyone to operate the device, called Vulcan, Borucki organized a program in which volunteers would take care of the night shifts required to keep Vulcan functioning.
It wasn’t too hard to convince people to pitch in. Researchers at SETI were eager for the Kepler team’s data so that they could point their giant radio telescopes at systems with Earth-size planets. Astrobiologists at Ames strongly supported the mission too. “We really believed in the potential of the project so we donated our time,” says Ames Integrative Studies Lead Lynn Harper. After many treks up to the observatory, Harper and other volunteers managed to find the money to enable Borucki to hire an operator.
Though the tests weren’t designed to spot terrestrial planets, other discoveries, later verified by spectroscopy, proved that the remotely operated camera was photometrically precise. “He’s shown that he can find eclipsing binaries, which are as hard to find as looking for transits,” says Koch.
Go Prove It
When the team came back with yet another Discovery proposal in 1998, reviewers complained that in space, cosmic rays or noise and jiggles in the spacecraft could interfere with the precision of the detectors. The Kepler team took it in stride. “They always loved the science [but] they always had a technical question about our ability to do the job,” says Larry Webster.
This time NASA granted Borucki a half-million dollars to build a demonstrator that could prove the proposed system would work. It was an unprecedented step for NASA headquarters. Ames agreed to match the amount, and within 88 days—Webster counted them one by one—the team assembled an end-to-end ground system. “We worked seven days a week, and had most of the machine shops in the [San Francisco Bay area] working with us,” Borucki says.
The Kepler Tech Demo, a 10-foot phone-booth-like steel-and-styrofoam frame, surrounded a single CCD, a coolant system, and other hardware. It took six months to get it working, and Borucki grew nervous. “We were spending Ames money like crazy,” he recalls, “and I was waiting for the moment they would say, ‘Hey Bill, great try, why don’t you move on to something else?’ ” The results from the contraption, however, clinched the deal: The Demo detected simulated planetary transits—brightness changes of 100 parts per million—in a mocked-up 1,600-star sky. In December 2001, reviewers ran out of criticisms. Kepler was chosen as a Discovery mission.
For Webster, NASA’s challenge made all the difference. “It was kind of a ‘We don’t quite believe you can do it. Go prove it. When you’re ready, come back,’ ” he recalls. “We did that in spades and came back in the 2000 proposal and there was just nothing left to critique. We were perfect.”
It wasn’t an unalloyed victory, though. Weeks later, following Borucki’s meeting with NASA managers, the Kepler team swallowed hard and turned mission development (everything up to launch) over to JPL—one of the two NASA centers, along with the Goddard Space Flight Center, designated to carry out missions beyond Earth orbit.