SPACECRAFT

Ariane 62 fairing

The Ariane 62 usable volume beneath payload fairing in single launch structure. This volume constitutes the limits that the static dimensions of the spacecraft, including manufacturing tolerance, thermal protection installation, etc shall not exceed.

Considering the volume available on the launcher fairing, different configuration options were considered during the CDF study, taking into account especially the solar array and SAR antenna configuration and accommodation (stored and deployed). Other factors to take into consideration were the mission profile, potential interferences, antennas position (VenSAR and SRS antennas wrt. HGA), and the radiators configuration in order to sustain the thermal requirements of the spacecraft.

Spacecraft stowed configuration

EnVision stowed configuration is shown without the launcher fairing. Approximate size is 2.0 x 2.0 x 2.0 m. The satellite has a compact body and the Solar Arrays, the SAR antenna and the SRS antenna are the elements stowed during launch and deployed in orbit. At the bottom right is the 420 N Main Engine. Also visible are 8 + 8 10 N thrusters for AOCS.

Spacecraft deployed configuration

EnVision deployed configuration and the position of the main deployable elements (i.e. SAR antenna, SRS antenna and Solar Arrays) in their selected positions as consolidated during the discussions in the CDF study sessions. Solar arrays are 97 kg with a 15.7 m2 area (57% solar cells, 40% optical reflectors). A fixed, 3-m HGA requires dedicated slews. Ka-Band downlink is 4.2 Mbps @ 1.7 AU [Venus superior conjunction], 75 Mbps @ 0.3 AU [Venus inferior conjunction] at transponder saturation limit.

Instrument locations

The location of the instruments are on the top panel of the spacecraft. This panel faces the launcher flight direction of the satellite in launch configuration. The top panel of the s/c will be nadir looking during observations.

Spacecraft top panel with mission instruments.
A detail of the EnVision Mission Instrument panel shows the distribution of the units.The top panel of the s/c will be nadir looking during observations.