Hybrid Space-Ground Observatories

Apr 27, 2023 - 11:00 am to 12:00 pm

Campus, PAB 102/103

John Mather (JWST) In Person and zoom

Zoom Recording

We can build hybrid systems, with hardware in space working closely with hardware on the ground, to observe and discover things we could never see before. With NIST-traceable photometric calibrators in space, we could advance fundamental physics, modeling of exoplanet hosts and other stars, and dark energy measurements. With orbiting laser beacons we could advance adaptive optics performance through the entire visible wavelength band, where the sky is darkest and angular resolution and sensitivity are the best. The beacons would use “astro-stationary” orbits, with apogee about 200,000 km, so that they appear to stand still in front of the target star. Given the D4 scaling law for observing speed with diffraction limited observations of point sources, a large telescope on the ground can readily exceed the sensitivity of proposed 6 m space telescopes. The beacons could enhance Extreme Adaptive Optics searches for exoplanets, without adding to stray light. Orbiting starshades working with the largest telescopes could enable direct imaging of an exo-Earth at 5 pc distance in a one-minute exposure. With an exposure of an hour, visible band spectra could show exo-oxygen and exo-water signatures despite terrestrial interference. Augmented by orbiting millimeter antennas, the Event Horizon Telescope could achieve far better angular resolution and image quality on black holes, observing additional targets beyond M87* and Sgr A*. I will outline these mission concepts and show the progress to date.