Coriolis (P98-2)

Coriolis [SpectrumAstro]

Coriolis is an Air Force Space Test Program and Office of Naval Research (ONR) mission to demonstrate remote sensing of global wind vectors using the Microwave Polarimetric Radiometry technique, as risk reduction for the Conical Microwave Imager Sounder (CMIS) element of the NPOESS system, and for demonstration of more rapid and more accurate predictions of geomagnetic disturbances to orbiting satellites through continuous observation of solar Coronal Mass Ejections (CME).

As prime contractor, Spectrum Astro has end-to-end system responsibility, including spacecraft design, manufacture, integration and test; experiment integration; space vehicle verification; launch processing; and on-orbit checkout. The spacecraft is designed to accommodate two government furnished payloads on a three year test mission:

• the Naval Research Laboratory's (NRL) WindSat, a 305 kg yaw-spinning multi-frequency polarimetric microwave radiometer experiment to passively measure the ocean surface wind vector; and
• the Air Force Research Laboratory's (AFRL) 35 kg Solar Mass Ejection Imager (SMEI), built by the United Kingdom's University of Birmingham and the University of California at San Diego, to monitor solar activity.

Key features of the Coriolis spacecraft design include extremely low levels of electromagnetic interference for compatibility with the ultra-sensitive WindSat radiometer (e.g., radiated emissions are < 6.5 dBµV/m at 6.8 GHz); and a system architecture to support the 30 RPM yaw spin of WindSat's rotating assembly, while providing power plus precise attitude knowledge and control.

WindSat extracts the brightness temperature data from the microwave energy emitted by the ocean and generates data products for downlink, while SMEI gathers data from its three optical cameras. Science data is continuously transferred to the spacecraft via a 1553B interface. Data is stored in mass memory and subsequently downlinked at up to 51.2 Mbps to a commercial X-band station with end-to-end latency as low as 4 hours. Following a year of on-board calibration and validation, the WindSat data products will also be continuously downlinked in real time to ground users employing small tactical terminals.

The Coriolis spacecraft was shipped to NRL in July 2001 for spacecraft level EMI testing, WindSat experiment-to-spacecraft integration, and space vehicle environmental testing. It was launched aboard a Titan-2(23)G on 6 January 2003. It is still active in early 2016.

An experimental replacement for Coriolis' Windsat payload was to be launched in 2018 on the ORS 6 (COWVR) mission, but this was cancelled. The COWVR payload will then fly on the STP-H8 ISS payload.