Operating Venus Express
All communications to and from Venus Express are controlled through one single centre, the Venus Express Mission Control Centre (VMOC), located at ESOC, ESA’s control centre, in Darmstadt, Germany.
Immediately after launch, the antenna dishes at the European deep-space ground stations at Villafranca, Spain (15 m), New Norcia, Australia, (35 m) and Kourou, French Guiana, (15 m) were used for communication and orbit determination.
When the spacecraft is in orbit around Venus, communication with Venus Express will be done using the 35 m antenna dish located at the new ESA ground station at Cebreros near Madrid, Spain. The 35m antenna in New Norcia will be used to support the Venus Radio science experiment (VeRa).
Once in orbit around Venus, Venus Express essentially plays on a ‘look-store-downlink’ mission scenario, already implemented for the Mars Express and Rosetta missions. The spacecraft will collect most of its scientific data during about one hour and a half passage over the pericentre, when the spacecraft is closer to the surface of the planet.
The part of the orbit where the spacecraft is farther from the planet will be shared between global remote sensing observations, in situ observations and periods of data transmission.
All data collected during observations are transmitted to Earth for about eight hours a day (one orbit around Venus is one day, or 24 hours, long). Eight hours of transmission correspond to the downlink of between 100 and 800 megabytes of data, depending on the actual distance between Earth and Venus.
NB 00:00 hours corresponds to the passage over the pericentre
Throughout the mission, ESOC will provide the Venus Express Principal Investigators with the complete sets of raw data acquired from their instruments, and with any other necessary spacecraft data, for further processing and analysis.
The ESA Venus Express Science Operations Centre (VSOC), located at ESTEC, ESA’s research and technology centre in Noordwijk, the Netherlands, is collecting and co-ordinating all observation requests from the Principal Investigators.
It also generates and cross-checks the instrument command files that are passed to ESOC for upload to the spacecraft. VSOC is also managing the Planetary Science Archive where all data will be stored and be available to the wide scientific community after the six-month period when the data are proprietary to the PIs.
The data will be archived in a standardised format that is now applied to all new planetary missions of ESA (the same is used for Mars Express and Rosetta).