Sentinel Space Telescope

Sentinel Space Telescope

Artist rendering of the Sentinel Space Telescope
Mission type	Space Telescope
Operator	B612 Foundation
Website	SentinelMission.org at the Wayback Machine (archived 8 October 2015)
Mission duration	≤10 years (planned)
Spacecraft properties
Manufacturer	Ball Aerospace
Launch mass	1,500 kg (3,300 lb)
Start of mission
Launch date	Cancelled
Rocket	Falcon 9
Orbital parameters
Reference system	Heliocentric
Main
Wavelengths	7–15 μm
Instruments
IRAC IRS

The Sentinel Space Telescope was^[1] a space observatory to be developed by Ball Aerospace & Technologies for the B612 Foundation.^[2][3] The B612 Foundation is dedicated to protecting the Earth from dangerous asteroid strikes and Sentinel was to be the Foundation's first spacecraft tangibly to address that mission.

The space telescope was intended to locate and catalog 90% of the asteroids greater than 140 metres (460 ft) in diameter that exist in near-Earth orbits. The telescope would have orbited the Sun in a Venus-like orbit (i.e. between Earth and the Sun). This orbit would allow it clearly to view the night half of the sky every 20 days, and pick out objects that are often difficult, if not impossible, to see in advance from Earth."^[4] Sentinel would have had an operational mission life of six and a half to ten years.^[5]

After NASA terminated their funding agreement with the B612 Foundation in October 2015^[6] and the private fundraising goals could not be met, the Foundation eventually opted for an alternative approach using a constellation of much smaller spacecraft under study as of June 2017^[update].^[1] NASA/JPL's NEOCam has been proposed instead.