Sunday, January 06, 2019

Hypertelescope: I in the Sky

Israeli researchers have come up with a way to make a low-cost but powerful "eye in the sky" using a constellation of many tiny satellites:

https://www.jpost.com/HEALTH-SCIENCE/BGU-imaging-system-can-produce-images-at-higher-resolution-and-lower-cost-575988

Technology like this could be very useful for India, given that ISRO has already demonstrated its ability to deploy large numbers of satellites in a single launch.


While it would be nice to use this hypertelescope technology to observe the heavens and image distant alien worlds in the search for life, there are other earthly applications which could be possible.


ISRO's HySIS (HyperSpectral Imaging Satellite) was recently launched into geostationary orbit, providing India a means to observe the Indian Ocean region continuously at all frequencies, but at a very low resolution. HySIS will allow India to detect the presence of large military ships in the Indian Ocean, but can't see in closer detail than that.

Most Earth-observation satellites, including spy satellites, are positioned in Low Earth Orbit, usually at a couple of hundred kilometers in altitude, passing over their target at periodic intervals. However, a geostationary satellite which continuously stays above the same spot due to its orbital period matching the Earth's rotation, requires an altitude of 40,000 km. Needless to say, this large distance is why spy satellites aren't typically put into geostationary orbits, and are instead limited to merely passing over their target periodically at lower altitude. But a a powerful hypertelescope in the form of a large constellation swarm of satellites could provide extremely high-resolution images of the Earth's surface even from distant geostationary orbit.

A large geostationary eye-in-the-sky positioned above the Iran-Pakistan region could provide otherwise impossibly high resolution images of the ground in realtime. It would be useful for India and Israel to collaborate on such projects as part of joint space cooperation -- after all, two I's are better than one.

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