WASHINGTON — Not a month after the Chelyabinsk meteorite strike prompted a series of congressional hearings here about dangerous asteroids, the nonprofit B612 Foundation unveiled new details about its plan to build and launch a $450 million asteroid-hunting telescope called Sentinel.

The price tag alone offers a new level of detail about the mission, which an official with Sentinel prime contractor Ball Aerospace of Boulder, Colo., said will resemble a cross between two space telescopes the company helped build for NASA.

“If we take what we learned on Spitzer and what we learned on Kepler, you can derive Sentinel,” John Troeltzsch, Ball’s Sentinel program manager, said April 9 during a press briefing at the National Space Symposium in Colorado Springs, Colo. Troeltzsch also is Ball’s program manager for the Kepler Mission, which launched in 2009 on a 3.5-year prime mission to search for potentially habitable planets orbiting distant stars.

B612 plans to launch Sentinel in 2017 or 2018 aboard a Space Exploration Technologies Corp. Falcon 9 rocket, possibly as a secondary payload, according to Troeltzsch. The telescope will be placed into a Venus-like orbit for its six-and-a-half-year mission to map the asteroids in the inner solar system with orbits that crisscross with Earth’s. Sentinel will be looking especially for space rocks with a diameter greater than 140 meters.

Stanford University professor Scott Hubbard, a former NASA official now working as B612’s program architect, said the Mountain View, Calif.-based foundation has raised about $2 million during the last six to eight months.

All funding raised so far has come from B612’s inner circle of angel investors, Hubbard said during the April 9 press briefing.

“We’re very hopeful and positive about another [funding] increment, because we are close to an agreement with Ball on this next phase of detector testing and preparations for the system review that will be coming up this year,” Hubbard said.

The foundation’s goal is to raise $30 million to $40 million a year for Sentinel, much of which likely will come from wealthy individuals, Hubbard said.

Sentinel’s main observatory comprises 16 infrared detector chips assembled into what Troeltzsch called a “compound camera.” This array would be sensitive to thermal energy radiated into space by target asteroids that are heated by the sun. Sentinel’s detectors will be tuned to flag reflections with wavelengths between 5 and 10.4 microns, Troeltzsch said. Prototyping for the detectors will happen over the next six to eight months, he added.

Because it is intended to spot larger “city killing” asteroids, Sentinel would not be the optimal instrument for detecting relatively small asteroids, such as the 25-meter rock NASA plans to haul to lunar orbit for astronauts to visit by 2025 or so, Hubbard said.

However, under a Space Act Agreement with NASA, B612 will give the agency access to the data the Sentinel telescope gathers in return for access to NASA’s Deep Space Network communication system, technical consulting, and access to personnel at the Jet Propulsion Laboratory’s Minor Planet Center, who will help vet and archive Sentinel data.

B612 took the Sentinel concept public last June. The nonprofit group’s chairman and chief executive is former astronaut Ed Lu. The Sentinel project manager is Harold Reitsema, former director of science mission development for Ball.



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Dan Leone is the NASA reporter for SpaceNews, where he also covers other civilian-run U.S. government space programs and a growing number of entrepreneurial space companies. He joined SpaceNews in 2011.Dan earned a bachelor's degree in public communications...