An interesting post today from Germany’s Fraunhofer Institute for High Frequency Physics and Radar Techniques, the folks who operate the TIRA space observation radar (located at Wachtberg, Germany). The radar will be used starting just after launch to observe Ariane 5 and ATV-4 so as to provide highly accurate orbit determinations; the data will be provided to the flight dynamics teams at ATV-CC and to a ground station in New Zealand.
Today just before midnight, an Ariane 5 launcher will start from the Spaceport in Kourou, French Guiana. On board is Automated Transfer Vehicle (ATV-4) Albert Einstein. Several challenging manoeuvres are necessary before it arrives at the International Space Station. TIRA, a unique Tracking and Imaging Radar developed by Fraunhofer FHR, will support this part of the mission of the European Space Agency vessel.
With tonight’s launch at 23:52 CEST, the week-long preparations at Fraunhofer FHR will come to a conclusion. A group of scientists and engineers will be busy all night to track ATV-4 and analyse the data.
Approximately 20 minutes after launch, the Ariane 5 rocket will enter the field of view of the TIRA radar. In this phase, it is the task of the Fraunhofer scientists to precisely measure the trajectory so as enable an ESA ground station New Zealand to be precisely pointed and acquire contact. This antenna will send the command to the rocket to separate from its upper stage.
In the next orbit after about 90 minutes later, the Ariane upper stage and ATV-4 will already be separated from each other – but still be very close – at an altitude of 250 kilometres. TIRA must clearly identify the space transporter so it can receive further commands from the ground.