Vega Suffered Telemetry Outage in First Flight

The otherwise successful inaugural flight of Europe’s Vega small-satellite launcher in February featured a loss of telemetry during the rocket’s crucial fairing-jettison phase as the ground-telemetry station was blinded by the rocket’s plume, European Space Agency (ESA) officials said Oct. 1.

The anomaly — apparently the only notable problem during the flight — will force Vega managers to either switch ground-telemetry stations for future flights, or change Vega’s launch path to permit the current tracking station to capture the telemetry. The change in flight paths likely would force a redesign of one or more of the rocket’s fuel tanks to permit a longer burn to compensate for the less-ideal trajectory.

In interviews and presentations here at the 63rd International Astronautical Congress (IAC), ESA officials said that, in a situation they had not anticipated, the Vega rocket’s trajectory during the ignition of its third stage lined up exactly with the ground telemetry station. The ground station was unable to capture telemetry as the signal was lost amid the plume particles emitted by the Zefiro-9 solid-fueled stage.

The Zefiro-9 was ignited 216.5 seconds after Vega’s liftoff from the Guiana Space Center in French Guiana, on South America’s northeast coast.

Five seconds later, the fairing that protected the eight satellites being delivered into two separate low Earth orbits was separated, an event important to register, especially during an inaugural flight.

Vega was at 135 kilometers in altitude when the Zefiro-9 stage began firing. By the time it finished its work about two minutes and 13 seconds later, the rocket was at 182 kilometers, according to a paper presented here by Stefano Bianchi, ESA’s Vega project manager.

In his presentation, Bianchi said Vega managers had to contend with “the interruption of the radio-frequency link during a significant part of the [Zefiro-9] propulsive phase, related to the [Zefiro-9] radiation effect under the aspect angle. This in particular affected the fairing separation phase, for which environmental and kinematics data could not be recovered.”

A task force including ESA; Vega prime contractor ELV SpA; the French space agency, CNES; and launch-services provider Arianespace was formed to determine how to mitigate the problem in future flights, Bianchi said.

Antonio Fabrizi, ESA’s director of launchers, said the 20-nation agency will be asking its member governments in November for a Vega-consolidation package that includes funds to avoid the problem in the future.

“We need to work on the first stage and either invest in a new ground station or in a new Vega trajectory,” Fabrizi said. “If we adjust the trajectory, that would result in a loss of performance, and we will need to compensate for that.”

Fabrizi said Vega is scheduled to make its next flight in March, when it will carry ESA’s Proba-V Earth observation satellite into polar low Earth orbit.

ESA has booked five Vega flights, starting with the Proba-V mission, as part of a 400 million euro ($500 million) program to guide the Vega program to a point at which its per-launch costs make it competitive on the global market.

With several Russian and Ukrainian converted ballistic missiles now facing questions as long-term space-launch alternatives, Vega managers believe the rocket should be able to establish itself as a reliable small-satellite launcher — if managers can get its prices down.

Vega’s ELV managers have said the vehicle now costs about 32 million euros, including the cost of Arianespace’s marketing and sales activities. If they can increase Vega’s launch rate from one per year now to four per year, that price could be reduced to 22 million, these officials have said.

Fabrizi agreed. “We have a window of opportunity now and it would be stupid not to catch it,” he said. “The various small improvements in the vehicle we are proposing [to the November meeting of ESA governments] should also help with the vehicle’s competitiveness.”

“One flight per year is not ideal,” Fabrizi said. “If Arianespace is able to increase the rate to three or four per year, Vega can be competitive.”

Fabrizi noted that despite Vega’s infancy, there are no plans at ESA to finance its operations in the same way that the heavy-lift Ariane 5 rocket is supported. Ariane 5 operating costs are financed at level of about 120 million euros per year.

“There is no need for this kind of support for Vega now,” Fabrizi said.

Credit: spacenews.com