of impact events with our planet, allowing for asteroid deflection by the use of gravity tractors to divert their trajectories away from Earth. In order to communicate with the spacecraft while it is orbiting the Sun (at about the same distance as Venus), which can be at times as far as 270 million kilometres (170 million miles) from Earth, the B612 Foundation entered into a Space Act Agreement with NASA for the use of their deep space telecommunication network. Design and operation Sentinel was designed to perform continuous observation and analysis during its planned -year operational life, although B612 anticipates it may continue to function for up to 10 years. Using its telescope mirror with sensors built by Ball Aerospace (makers of the Hubble Space Telescope's instruments), its mission would be to catalog 90% of asteroids with diameters larger than . There were also plans to catalog smaller Solar System objects as well. The space observatory would measure by with a mass of and would orbit the Sun at a distance of approximately the same orbital distance as Venus, employing infrared astronomy to identify asteroids against the cold of outer space. Sentinel would scan in the 7- to 15-micron wavelength band across a 5.5 by 2-degree field of view. Its sensor array would consist of 16 detectors with coverage scanning "a 200-degree, full-angle field of regard". B612, working in partnership with Ball Aerospace, was constructing Sentinel's 51 cm aluminum mirror, designed for a large field of view with its infrared sensors cooled to using Ball's two-stage, closed-Stirling-cycle cryocooler. B612 aimed to produce its space telescope at a significantly lower cost than traditional space science programs by making use of space hardware systems previously developed for earlier programs, rather than designing a brand new observatory. Schweickart stated that about "80% of what we're dealing with in Sentinel is Kepler, 15% Spitzer, 5% new, higher-performance infrared sensors", thus concentrating its R&D funds on the critical area of cryogenically-cooled image sensor technology, producing what it terms will be the most sensitive type of asteroid-finding telescope ever built. Data gathered by Sentinel would be provided through existing scientific data-sharing networks that include NASA and academic institutions such as the Minor Planet Center in Cambridge, Massachusetts. Given the satellite's telescopic accuracy, Sentinel's data may have proven valuable for other possible future missions, such as asteroid mining. Mission funding B612 was attempting to raise approximately $450M