PARIS — European officials say a software change should correct a problem on the inaugural Ariane 6 launch in July that prevented the rocket’s upper stage from performing a final maneuver.
The Ariane 6 task force, which includes the European Space Agency, French space agency CNES, ArianeGroup and Arianespace, said in a joint statement Sept. 16 that a review of the data collected during the July 9 inaugural launch found “no showstoppers” for a second mission, currently scheduled for the end of this year.
That inaugural launch was not perfect, though, as the Vinci engine in the rocket’s upper stage failed to reignite for a final burn to deorbit the stage. The stage’s auxiliary propulsion unit (APU) did not start up during a long coast phase, which prevented the Vinci engine from performing that final burn at the end of the mission, leaving the stage in low Earth orbit.
In its statement, the task force said that one temperature measurement exceeded a limit, triggering a shutdown of the APU. Engineers will implement a software change to adjust the chill-down of the APU “to improve ignition conditions and solve the identified anomaly.”
That will not require any changes to vehicle hardware itself. The software change will be implemented before the next Ariane 6 launch, of the French military’s CSO-3 reconnaissance satellite, said Stéphane Israël, chief executive of Arianespace, during a Sept. 16 briefing held in conjunction with World Space Business Week here.
“We could have done the second flight without correcting it,” he said, since the mission does not require multiple burns of the Vinci engine to place the satellite in its planned orbit. “But we want to deorbit the second stage during this second flight, and to deorbit the upper stage we need to correct what has happened.”
He added that the software change needed to fix the problem should be “quite easy” to implement. The task force statement mentioned a “few unexpected behaviors” with the inaugural launch but didn’t elaborate on those issues and any changes needed for the second launch.
Israël said Arianespace is still planning to conduct the second Ariane 6 launch by the end of the year, weeks after the return to flight of the Vega C rocket currently planned for late November or early December, even with the APU software change. “We will see if we match this objective in the coming weeks and months,” he said of the schedule.
