Author Topic: Ariane 5 delivers SES-14 and Al Yah 3 to orbit despite telemetry loss  (Read 83 times)

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Ariane 5 delivers SES-14 and Al Yah 3 to orbit despite telemetry loss

The two satellites that launched Thursday evening on an Ariane 5 are in orbit and communicating with the ground despite a harrowing loss of contact with the rocket a few seconds after the its upper stage ignited.
SpaceNews.com

            Updated at 8:49 p.m. Eastern. 
WASHINGTON — The two satellites that launched Thursday evening on an Ariane 5 are in orbit and communicating with the ground despite a harrowing loss of contact with the rocket a few seconds after the its upper stage ignited.
The Ariane 5 lifted off at 5:20 p.m. EST from the Guiana Space Center in French Guiana carrying the SES-14 and Al Yah 3 communications satellites. During Arianespace’s live webcast of the launch, the launch appeared to be going well through separation of the first satellite, SES-14, about 27 minutes into the flight. The second satellite, Al Yah 3, riding in the rocket’s lower berth, was scheduled to deploy about eight minutes later. Instead of confirming separation, the Arianespace webcast eventually cut away from the live launch animation to pre-recorded footage of the Ariane 5 prior to launch.
About 20 minutes after that, Arianespace CEO Stephane Israel appeared on camera to announce that the team had lost contact with the rocket and had not yet heard from the satellites.
“[W]e have had an anomaly on this launch. Indeed, we lost contact with the launcher a few seconds after ignition of the upper stage,” he said. “Up to now, our customers do not have contact with the satellite. We need now some time to know if they have been separated, and where they are exactly, to better analyze the consequences of this anomaly.
“Arianespace, in full transparency, will come back to you to provide you with some more information as soon as we have them. I apologize on behalf of Arianespace,” Israel concluded.
An hour and a half after Israel spoke, Arianespace released a statement saying “both satellites were confirmed separated, acquired and they are on orbit. SES-14 and Al Yah 3 are communicating with their respective control centers. Both missions are continuing.”
A live animation from Arianespace’s webcast showing separation of SES-14.
Arianespace did not say whether the satellites are in their intended orbits, and did not immediately respond to a SpaceNews inquiry. 
SES-14 is an all-electric satellite that normally requires months to reach its geostationary slot — a timeline heavily influenced by launcher accuracy. SES said prior to launch that the satellite was expected to enter service in July. In addition to its communications payload, SES-14 is carrying NASA’s Global-scale Observations of the Limb and Disk science payload. 
Yahsat’s Al Yah 3 uses chemical propulsion and was designated for a super-synchronous orbit with an apogee of roughly 45,000 kilometers. Onboard propulsion has the job of circularizing the orbit to the geostationary arc at 36,000 kilometers over the course of five burns.
Ariane 5 lost telemetry a few seconds after ignition up the upper stage and the outage lasted “throughout the rest of powered flight,” according to the Arianespace statement. The loss of contact with the rocket became apparent when “the second tracking station located in Natal, Brazil, did not acquire the launcher telemetry.”
Israel, in his speech, apologized for the anomaly. “We know that there is no launch with no risk. We know that launch is always difficult, and tonight Ariane 5 has had an anomaly, so let’s take time now to better understand the situation of the satellites.”
Ariane 5 has completed 82 successful missions since a December 2002 failure that destroyed two satellites — Eutelsat’s Hot Bird 7 and France’s experimental Stentor communications satellite. Those 15 years of smooth sailing have allowed Arianespace to market the rocket as the champion of reliability.
It is unclear what impact tonight’s anomaly will have on Arianespace’s target of completing 14 launches this year — a goal announced just two weeks ago. The SES and Yahsat mission, designated VA241, is the first of those 14.
 
SpaceNews.com

Source: Ariane 5 delivers SES-14 and Al Yah 3 to orbit despite telemetry loss