Two venture capitalists and a Facebook manager joined the B612 Foundation’s Founding Circle by donating at least $25,000 to the group’s bid to launch the world’s first privately funded deep-space mission.

The Mountain View, Calif.-based nonprofit announced this summer that it is negotiating a firm, fixed-price contract with Ball Aerospace & Technologies Corp. of Boulder, Colo., to build the mission’s Sentinel spacecraft and half-meter telescope. Launch is targeted for 2017 or 2018, when a Space Exploration Technologies Corp. (SpaceX) Falcon 9 rocket would send the asteroid-tracking spacecraft into solar orbit near Venus.

The Founding Circle donors announced Sept. 19 were: Steve Krausz, general partner of US Venture Partners; James Leszczenski, engineering manager at Facebook; and Shervin Pishevar, managing partner at Menlo Ventures.

The B612 Foundation also announced the addition of several new members to its strategic and science advisory board, including Roger Blanford, the Stanford University professor who recently chaired the National Academy of Sciences’ Decadal Survey of Astronomy and Astrophysics.