An update from Jean-Michel Bois, head of ESA’s mission team at ATV Control Centre, on today’s debris avoidance:
This evening the ATV Control Centre performed the first-ever International Space Station Predetermined Debris Avoidance Manoeuvre (PDAM) using ATV Georges Lemaître to boost the orbiting science complex 0.5 m/s at 17:42 GMT (18:42 CET).
The objective was to avoid an object – 34881 (COSMOS 2251 debris) – set to cross the Space Station’s orbit at 20:13 GMT (21:13 CET). The slight change in the Station’s orbit due to the undocking of the Progress 51P this morning was not enough to avoid the debris.
The PDAM time computation did not put the Space Station in a risky situation with respect to other debris (in particular, object 31289 from FENGYUN 1C, that is passing close but that was not critical in the Station’s initial orbit).
A PDAM procedure was initiated by the Station’s international community in 2012 in response to a late detection of debris – just 6 hours before conjunction!
A PDAM activates a predefined manoeuvre with a unique boost value. This ‘coarse’ manoeuvre is enough to avoid a specific debris object and avoids the long computations necessary to define a tuned trajectory and boost value. The previous PDAM used the Russian Progress cargo vessel thrusters, but since ATV-4, ATV-CC can do the procedure as well.
This manoeuvre demonstrates again the reliability of ATV and the skill of the joint ESA/CNES ATV operations teams. ATVs have delivered all services they were designed for over the course of their five missions.