Orbital Rolls Antares to NASA Pad To Prepare for Hold down Test

Orbital Sciences Corp. on Oct. 1 rolled the first stage of its Antares rocket out to the launch pad at NASA’s Wallops Island Flight Facility to prepare for a series of tests that, if successful, will clear the way for the company to begin routine cargo deliveries to the international space station sometime next year.

Orbital wanted to move the Antares stage to the pad Sept. 27, but a power problem with a transporter vehicle used to haul the rocket from its hangar to the pad, coupled with expectations of foul weather on the Virginia coast during the weekend, prompted the company to delay rollout until Oct. 1, spokesman Barron Beneski said.

Orbital holds a $1.9 billion NASA contract signed in 2008 that calls for eight cargo flights to the space station.

Orbital will deliver that cargo with its unmanned Cygnus space freighter, which Antares will loft to low Earth orbit from Wallops.

Before it can collect on the delivery contract, however, Orbital has to complete a hold-down test of the Antares first stage, then conduct two Antares demonstration flights out of Wallops.

The first-stage hold-down test will take place at the pad sometime in the next four to five weeks, Orbital said in its Oct. 1 press release.

In the hold-down test, the rocket core’s two liquid engines — Soviet-vintage NK-33s refurbished by Sacramento, Calif.-based Aerojet and rebranded as AJ-26s — will be lit for about 30 seconds.

Antares would have its maiden flight a month after a successful hold-down test, Orbital said Oct. 1.

Assuming a successful test flight, a full-up Antares-Cygnus stack would be cleared to fly a demonstration cargo run to the space station before the end of the year, Orbital said.

In that mission, Cygnus would deliver 550 kilograms of freight and relieve the outpost of about 1,000 kilograms of trash, Orbital said.

Antares will launch all of its space station resupply missions from Pad 0-A at the Mid-Atlantic Regional Spaceport (MARS), a facility at the southern tip of Wallops Island that is operated by the state-funded Virginia Commercial Spaceflight Authority.

Because MARS and Pad 0-A are on a NASA range, the agency had to give its approval for Orbital to begin operations at the launch pad.