SES communications satellite in Florida for Falcon 9 launch
BY STEPHEN CLARK
Posted: October 5, 2013
A communications satellite booked for the next launch of the Falcon 9 rocket was transported by truck from Virginia to Florida this week as SpaceX seeks to allay the worries of the payload's owner - the global commercial operator SES - and the insurance community after the Falcon 9's test flight Sunday encountered a second stage engine restart anomaly.
SES 8 is slated to be the payload for SpaceX's next Falcon 9 launch, which is scheduled for no earlier than Nov. 1. But the launch depends on the outcome of an inquiry into the cause of a problem with the second ignition of the Falcon 9's upper stage on Sunday's launch from Vandenberg Air Force Base, Calif.
The launch of SES 8, which will be released in a supersynchronous transfer orbit stretching above its 22,300-mile-high operating post, requires two burns of the Falcon 9 second stage. The first firing will place SES 8 in a low-altitude parking orbit, then the second burn is designed to inject the 7,055-pound craft in an oval-shaped orbit.
SES 8 will maneuver itself into a circular orbit 22,300 miles over the equator, sliding into position in the geostationary arc at 95 degrees east longitude. The satellite will beam television and other services to fixed and mobile users across India, Indonesia and Indo-China.
Luxembourg-based SES announced the Falcon 9 launch contract for SES 8 in March 2011, but the company stipulated it wanted SpaceX to demonstrate its upgraded Falcon 9 v1.1 rocket on a test flight before it would approve SES 8's launch.
Yves Feltes, an SES spokesperson, said the company needs a "satisfactory technical explanation" for the restart anomaly Sunday on the Falcon 9 upper stage.
"There are still two issues with the launch at this stage," Feltes said. "One is the shutdown of NASA. We don't really know how that is going to affect us. This is an uncertainty right now. Then there is the issue of the reignition of the upper stage, which is required for geostationary transfer orbit, and therefore the launch of SES 8."
Sunday's flight successfully delivered Canada's Cassiope space weather satellite to orbit, demonstrating the upgraded launcher's new Merlin 1D engines, a 17-foot-diameter payload fairing, a more reliable stage separation system and a triply redundant flight computer.
SpaceX programmed the second stage to reignite its vacuum-rated Merlin 1D engine after deploying Cassiope and a cache of secondary payloads, but the upper stage aborted the burn during the ignition sequence, said Elon Musk, SpaceX's CEO.
"In the case of the upper stage relight, we initiated relight and the system encountered an anomaly and did not complete the relight," Musk said. "We believe we understand what that issue is and should have it addressed in time for the next flight of Falcon 9. Other than that, the ascent phase was excellent. That final burn was actually just a sideways burn, just to check propellant residuals."
Musk told reporters after Sunday's launch that he expected the restart anomaly could be fixed relatively easily.
"Before deciding what the issue was, I think we want a little bit more time to read the data before coming to any sort of definitive conclusion," Musk said. "But we saw the engine initiate ignition, get up to about 400 psi, and then it encountered a condition that it didn't like. We think that it may have been due to an extended spin start, maybe, but this is speculative. So it initiated an abort of the restart. We have all the data from the restart, so I'm confident we'll be able to sort it out and address it before the next flight. It's nothing fundamental."
The second stage of the Falcon 9 rocket uses a modified version of the Merlin 1D engines which power the launcher's first stage. The changes include a niobium nozzle, which glows red hot when the engine is firing.
"On the test stand, we've restarted the Merlin 1D engine sometimes dozens of times. We just have to work out some slight differences of it working in vacuum," Musk said.
SES 8 will be the first commercial communications satellite launched by a U.S. rocket company since 2009, when Lockheed Martin and United Launch Alliance put an Intelsat satellite in orbit on an Atlas 5 rocket.