CubeSats could help calibrate future space telescopes

Segmented space telescopes such as the James Webb (JWST) – currently set to launch in 2021 – need to remain incredibly still when taking measurements, particularly when investigating exoplanets in other solar systems. The variations in light they need to detect are miniscule and the slightest movements can throw them off. Complimentary CubeSats, positioned a few thousand kilometres away, could act as ‘guide stars’ for space telescopes, allowing the giant instruments to calibrate themselves periodically in space.

Though there are currently no plans to use small satellites in this way for the JWST, its proposed successor, LUVOIR (Large UV Optical Infrared Surveyor), will potentially employ the technology. To achieve its desired accuracy, LUVOIR will need to remain perfectly still within 10 picometres, which is around a quarter the diameter of a hydrogen atom. In a paper in The Astronomical Journal, the MIT team describes a laser communications system that could be deployed on a CubeSat and enable LUVOIR to maintain the requisite level of stability. This in-orbit calibration would reduce the need for exhaustive levels of testing on the ground and ultimately help keep the costs of these marquee projects down.