On 28 November 2014, the flight control team at ESOC reported loss of contact with Venus Express.
It is possible that the remaining fuel on board VEX was exhausted during the recent periapsis-raising manoeuvres (see blog post here) and that the spacecraft is no longer in a stable attitude (the spacecraft’s high-gain antenna must be kept pointed toward Earth to ensure reliable radio contact).
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 oriented with its solar arrays pointing toward the Sun, and is rotating slowly.
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 (fuel situation or otherwise) remains to be established.
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.