Florad # 2

To show the MIOSAT platform flexibility  Spacesys proposed to Rheinmetall to study the compatibility of that platform with the FLORAD payload.  In addition we wanted to demonstrate  the possibility of flying all three minisatellites making up the FLORAD  constellation,  on board VEGA.

MIOSAT-derived platform for a three-bands MMW radiometer payload

The Study performed by Spacesys on a subcontract to RHI aimed at adapting the MIOSAT platform to exploit the  MMW region beyond 80 GHz to complement other satellite data for the purpose of improving the medium term regional weather prediction, and longer term climate change forecasts. A small constellation of minisatellites injected in LEO  with a circular or slightly elliptical orbit, was assumed as a goal for the Study, with the additional self-imposed constraint of demonstrating that three satellites, as a minimum, could be launched towards the destination orbit by a single VEGA launch.

The platform was partly modified, the key addition being two lateral  solar array wings to better cope with the payload power demand during eclipses. Due to the limited transversal dimensions of the service module - including the solar panel extensions which are fixed mounted- three spacecraft can be fitted inside the VEGA shroud envelope. 

The Study went in some depth about the payload and its integration in the  modified platform. Since the operating system would have three operating satellites, redundancies were minimized. The payload features a rotating fully offest paraboloid fed by a conical multiband horn fixed mounted to the satellite. This geometry redirects the RF beam towards Earth: a rotation of the reflector around the spacecraft roll axis, coincident with the feed axis, results in a linear,raster-type, scan which is limited to +-60° around the nadir. A robust auxiliary structure carries a temperature controlled fine grain absorbing mat used for hot calibration. Cold calibration is, instead, obtained when the antenna beam looks at the cold sky. 

The MMW  section is based on professional HW while the remaining channellized and video sections  can be fully miniaturized.  An extended survey demonstrated the availability of most of the required components, which is instrumental to shorten the payload development time and costs. The payload is mounted on a spacecraft panel which can be easily assembled on the Service module. The electronic boxes are installed on the inner panel side, while the antenna components, including a flat fixed structure carrying the hot load, are externally mounted.