Posted on 5 December 2014 by Daniel
Venus Express anomaly
(Updated 08.12 with additional clarifications from the operations team) On 28 November 2014, the flight control team at ESOC reported lack of contact with Venus Express at the first opportunity for communication with a ground station after execution of the 6th of the pericentre-raising manoeuvres.
It is possible that the remaining propellant onboard VEX was exhausted during the manoeuvre (see blog post here).
Repeated attempts to re-establish contact using ESA and NASA deep-space tracking stations have been made since then, and there has been some limited success in the period since 3 December.
Although a stable telemetry link is not available, some telemetry packets were successfully downlinked. These confirm that the spacecraft is currently in survival mode pointing the solar arrays to the Sun; the spacecraft is in a ‘2-axes stabilised’ mode, meaning that it is rotating around the axis of the line connecting VEX to the Sun (the ‘Sun line’).
The operations team is currently attempting to downlink the table of critical events that is stored in protected memory on board, which may give details of the sequence of events which occurred over the past few days. The root cause of the anomaly (propellant situation or otherwise) remains to be established and investigations are on-going.
We will provide an update as soon as something more concrete is known.
Today, Venus Express is in the eighth year of its fantastic mission – pretty good for a satellite originally designed for just two years of orbiting in Venus' challenging conditions.