Here we briefly describe the spacecraft, its payload, performances, data analysis and data dissemination to the astronomical community. ULTRASAT’s key performance characteristics are given in Table 1. The ULTRASAT spacecraft will be constructed by the Israeli Aerospace Industry (IAI). It will carry a single instrument - a wide field of view (204 deg2) telescope constructed by Elbit/Elop, with a focal-plane array (i.e, "camera") constructed by DESY, including a UV-optimized detector produced by TowerJazz and designed by AnalogValue. It will reach a 5σ sensitivity of 22.4 ABmag limiting magnitude in the mission band (230-290 nm; hereafter NUV) in 3x300s integration (based on detailed S/N calculations).
ULTRASAT will be launched to geostationary transfer orbit (GTO) and then self-perform GTO-GEO transfer to acquire its final Geosynchronous Earth Orbit (GEO) position. It is planned for a minimum 3-year mission operation, with sufficient propellant for a 6-year science mission.
| Property | Value | Comments | |
|---|---|---|---|
| Mission lifetime | 3 years | Propellent for 6 years | |
| Orbit | GEO | ||
| Total FoV | 204 deg2 | Covered by 4 dies | |
| Operation waveband | 230-290 nm | ||
| Cadence | 300 s | For the high cadence survey | |
| Mean effective PSF | 8.3’’ |
In central 170 deg2 For T = 20,000 K blackbody source |
|
| Mean limiting magnitude (in 900s, 5σ) | 22.4 ABmag |
In central 170 deg2 For T = 20,000 K blackbody source |
|
| Real-time download of data | Continuous | ||
| Transient alert after image capture | < 15 min | For both survey and ToO modes | |
| Sky accessibility at any given moment | > 50% | ||
| Observation start after ToO trigger | < 15 min | At any visible position | |
Table 1