Update from ESA Mission Director Jean-Michel Bois at ATV-CC.
The chase is on!
Tonight’s three manoeuvres are complete. ATV-5 is now behind the ISS and ready to perform the rendezvous and docking on 12 August at 13:30 GMT (15:30 CEST).
After the fly-under on 8 August, ATV was located in front of, and below, the ISS. To put ATV into its nominal position to perform tomorrow’s docking, Georges Lemaître had to be brought back behind Station.
On 9 August, as set of boosts (‘TA manoeuvres’) were performed to boost ATV above the ISS; moving the vessel higher than the ISS means it will move at a slower speed relative to the ISS. During 10 August, ATV drifted slowly back above the ISS.
Tonight, we performed the ‘TB symmetrical manoeuvres’ to move ATV back down below and behind the ISS, and ATV is now chasing Station.
The three TB boosts performed today comprised:
- TB1 : at 16:55:49 GMT , retrograde manoeuvre of -4.00 m/sec of delta velocity
- TB2 : at 17:47:20 GMT , retrograde manoeuvre of –8.08 m/sec of delta velocity
- TB3 : at 18:44:10 GMT, retrograde manoeuvrer of -2.89 m/sec of delta velocity
The main OCS (orbital control system) thrusters were used to perform these boosts, with a very high accuracy estimated at 0.3%
— JMB, Mission Director on console