Presentation #317.03 in the session Hybrid Missions Introduction.
The ORCAS mission, a first-of-its-kind hybrid space and ground observatory, will enable new science, otherwise only accessible to flagship class missions over a decade from now, at a SmallSat budget, providing unprecedented angular resolution, exquisite sensitivity and a unique flux calibrator. By enabling adaptive optics and flux calibration observations, ORCAS will deliver highly detailed images, unlocking the ability to detect a population of supermassive black hole binaries for the first time, as well as constraining the number densities of the faintest star forming clumps and understanding dark energy by measuring the distances of 10-billion-year-old supernovae. It will also deliver calibrated light that will vastly improve cosmology measurements, among many other advances. The low-cost ORCAS mission operating in collaboration with the W. M. Keck observatory will provide Great Observatory quality capabilities open to all US observers via a community driven observation plan. These observations will result in unique science for the mission, while also complementing and extending the science of HST, JWST, and Roman, as well as other potential future missions.
ORCAS mission objectives are met by a new combination of space and ground hardware which will enable high performance Adaptive Optics (AO) at visible and NIR wavelengths on the Keck 10 m telescopes. We deploy low-risk flight hardware, which includes a commercial ESPA-Grande class satellite bus with solar electric propulsion (SEP) carrying a modified commercial laser module as an AO beacon and a photometric calibrator. The spacecraft is positioned in a 5-day Highly Elliptical Orbit (HEO), enabling 3 AO observation opportunities per orbit, such that the spacecraft remains within the isoplanatic patch (region of good AO performance) for periods of up to a few hours (target declination and wavelength dependent). The available mission sky coverage is the Keck observable sky. The bus is augmented with a high-altitude GPS system demonstrated by GSFC on the MMS (Magnetospheric Multiscale) mission, enabling high precision orbit management to place the ORCAS predicted trajectory within (± 3 milliarcsec, 3σ). ORCAS will enable ∼ 300 AO observations and 1,500 photometric observations throughout its 3-year mission lifetime.