SHARPEx: the first space-to-space VLBI Experiment

Kurzfassung

Space is the next frontier for high resolution imaging with very long baseline interferometry (VLBI). The limited size of the Earth and atmospheric absorption and turbulence at high frequencies prevent order-of-magnitude resolution improvements from current black hole imaging with the Event Horizon Telescope. A 2 or 3-element submm space-based array like SHARP would image the thin black hole photon ring and measure the black hole spin and spacetime. We present the SHARP Experiment (SHARPEx) mission concept. SHARPEx will demonstrate key enabling technologies for space-to-space VLBI, including clock synchronization between two satellites, on-board correlation, and sub-wavelength orbit determination. SHARPEx will consist of two CubeSat or SmallSat platforms carrying small (~1 m) antennas, observing at cm wavelengths. Depending on the intersatellite link properties (range and bandwidth), a follow-up of SHARPEx may produce images of bright AGN with unprecedented resolution and fidelity.