Following an investigation into the Jan. 28 engine shutdown of a Delta II during a launch attempt of the ARGOS satellite, the Boeing [NYSE: BA] launch team determined that a propellant valve on vernier engine number two failed to open on command. This caused the engine shutdown and initiation of the autosafe mechanism on the launch vehicle.
The valves on both vernier engines have been removed and replaced and the launch team is preparing for a Feb. 7 launch attempt. The 30-minute launch window opens at 2:39 a.m. PST.
The first stage of a Delta II has a main engine and two vernier engines. Vernier engines are small rocket motors that allow the vehicle to be steered during flight. During the engine start sequence, the two vernier engines are required to ignite prior to ignition of the main engine. The main engine and two vernier engines were automatically shut down at approximately T-0 when it was detected that one of the vernier engines had failed to ignite. All vehicle safing systems performed as designed and expected.
The ARGOS launch has two NASA-sponsored secondary payloads, Ørsted and SUNSAT. These scientific satellites will be the first launched by Denmark and South Africa, respectively. There was no impact to any of the spacecraft systems as a result of the on-pad abort of the launch.
There will be a live broadcast of the launch beginning at 2:30 a.m. PST through spacecraft separation on: GE 2C, transponder 6, located at 85 degrees west, uplink frequency 6045 (vertical), downlink frequency 3820 (horizontal).
Delta II ARGOS Media Kit