After the original undocking was postponed on 26 September due to a technical glitch in Station configuration just minutes before the planned 00:35 departure, a new departure time had been set for 23:00 CEST, 27 September.
However, this, too, will be delayed. Instead, ATV-3 will perform a short-notice debris avoidance manoeuvre (DAM) in order to safely boost the Station away from a possible conjunction with a piece of the defunct Indian PSLV rocket.
The decision came during today's ISS Mission Management Team (IMMT) meeting, the body comprising all international partners that manages the Station.
When ATV is docked, the Station's other propulsion systems cannot be used for DAM burns. Since Edoardo Amaldi is still attached, it will now be called on to perform the DAM.
The DAM is expected to take place at 14:12 CEST.
The joint ESA/CNES mission control team at ATV Control Centre have already started planning the DAM operation for tomorrow. Engineers will be on console in the main control room as of 10:00 CEST to oversee the critical manoeuvre. The burn will target changing the Station's orbital velocity by just 0.3 metres/second – small, but sufficient to do the job.
"It's part of our business. Technical problems and unexpected developments can really affect how we work and what we do from day to day," says Jean Michel Bois, head of ESA's mission team at ATV-CC.
"Just a couple days ago, we were looking forward to the successful conclusion of ATV-3; tonight, we are planning for an important debris avoidance manoeuvre. We've got a professional and dedicated team, so I know we can handle anything that space throws our way."
Whether ATV-3 could make use of the next potential undocking slot on Friday, 28 September, will be decided later tomorrow.
For now, all eyes are on ATV and its powerful engines.
Details will of course be posted here in the ATV blog.