The ESA, CNES and industrial support teams at ATV-CC are hard at work today preparing the vehicle for departure from the ISS tomorrow. ESA’s Charlotte Beskow, taking a short break from her work as part of the Engineering Support Team (EST), gave us a quick update just a few minutes ago.
Since departure preparations began, around 11:00CET this morning, teams have been working to configure all the systems needed to operate ATV-5 once it’s in free flight. These include the propulsion system, telecommunications and guidance and navigation. Various parameters also have to be updated for undocking, including setting the GPS almanac.
All these systems have to perform without the (failed) No. 4 power chain (the battery is no longer functioning), and the challenge today is that the team have to configure the rest of the vessel’s systems to fly without ‘thinking’ that there’s a problem.
Charlotte says that ATV stores numerous pre-defined alarms on board, and when certain limits or criterion are reached/exceeded, the vessel sounds an alarm to let controllers on Earth know there’s a problem. Therefore, teams have to go through all the alarm limits and filter out those that are due solely to the failed (and fully known/characterised) power chain. “We need to ensure that ATV doesn’t overreact,” says Charlotte.
The team are getting most of the departure preparations done today, since the undocking timeline tomorrow is very tight.