SpaceX Launch Positioned Eutelsat, ABS Satellites For Faster Start
PARIS — The two commercial geostationary-orbit telecommunications satellites launched March 1 aboard a SpaceX Falcon 9 rocket — a launch that debuted the rocket’s dual-launch-to-geo capability and a new all-electric satellite design by Boeing — are expected to reach their final orbits at least a month ahead of schedule, their owners said.
The owners, ABS of Bermuda and Eutelsat of Paris, said a particularly good launch injection by the Falcon 9 is the main reason why the ABS-3A and the Eutelsat 115 West B spacecraft will reach their operating stations in late August and late September, respectively.
ABS and Eutelsat both disputed industry rumors of a Falcon 9 underperformance in the days following the launch. It now appears that the suspected launch anomaly was in fact a better-than-expected performance by the Falcon 9.
Eutelsat officials said the confusion may have been due to the fact that the Falcon 9 vehicle was operated in “minimum residual” shutdown mode rather than in “guided command” shutdown. Minimum-residual mode uses a higher percentage of the total fuel available, in effect pushing the satellites a bit closer to their destination.
ABS Chief Executive Tom Choi said immediately after the launch that the Falcon 9 performed better than expected and would reduce the time-to-destination below the expected eight months.
Choi reiterated this on May 14, saying ABS-3A likely will be in geostationary position in late August, six months after launch. As the lighter of the two satellites, ABS-3A was in the upper position in the unusual one-atop-another configuration that is a selling point for the Boeing all-electric 702SP design. ABS-3A weighed about 1,900 kilograms at launch.
Eutelsat spokeswoman Vanessa O’Connor on May 13 said the Eutelsat 115 West B, which weighed 2,200 kilograms at launch, is now expected to arrive at its destination in late September, at least a month earlier than expected.
Boeing Space and Intelligence Systems of El Segundo, California, has made the dual-stack feature a key selling point for the 702SP when launched aboard a Falcon 9. The low weight of electric-propulsion satellites compared to their chemical-propellant counterparts, combined with the ability to put one satellite on top of another without the need for a separate structure separating them means owners get two satellites in orbit with a single $60 million Falcon 9 launch.
As Boeing has found out since its original March 2012 four-satellite deal with ABS and Satmex -— since purchased by Eutelsat — the scenario works only when one or two satellite owners have satellite development programs that coincide so closely that a Falcon 9 launch of both can be reserved two or three years in advance.
Boeing has since been unable to find a two-satellite pairing. It has sold just one commercial 702SP since the original deal, to SES of Luxembourg, which will be launching it in the lower position on a European Ariane 5 rocket.
Most satellite industry officials — satellite owners, builders and operators — agree that partial- or all-electric configurations are the coming trend for commercial geostationary satellites. The debate now is over the tradeoffs between weight savings, which result in lower launch costs, and the time it takes to reach orbit and begin generating revenue.
Lockheed Martin Space Systems of Sunnyvale, California, Airbus Defence and Space of Europe have said their electric propulsion technologies will cut the orbital journey time by as much as 50 percent compared to the Boeing 702SP. In addition to the earlier revenue, that would mean the satellites spend less time in the Van Allen radiation belt.
Whether these companies’ products weigh more than Boeing’s, and how owners might view that set against the promise of adding more payload onto a lighter satellite, is one of the many issues being discussed by fleet operators.
Choi said that ABS-3A likely will reach its destination before Eutelsat’s satellite because of its lower mass and was in the upper position under the Falcon 9 fairing. So far, he said, there is no indication of any radiation effects.
“All systems are checking out fine and we left the Van Allen belt with no issue,” Choi said. “As far as I can see, the all-electric satellite platform is a success.”