Antares rocket rolls out to the launch pad on Oct. 1, 2012. Orbital plans a hot-fire test of the Antares first stage, the maiden flight of an Antares rocket, and a cargo delivery demonstration mission to the ISS

Antares raised on the launch pad

Launch on April 21 - Photo credit: Orbital/Thom Baur

Mission details:

• Orbital's Antares rocket's first launch attempt was canceled on Apr 17, 2013 due to unfavorable upper level wind conditions. Teams are working a 24-hour turnaround to make the next launch attempt on Sunday, April 21 with the launch window opening at 21:00 UTC. If successful its first stage will be the first liquid rocket launch from Wallops to space since 1974.
• Orbital Sciences has conducted a successful test flight of its Antares launch vehicle on April 21, 2013. Antares embarked on its maiden flight at 21:00 UTC, blasting off from Pad 0A at the Mid-Atlantic Regional Spaceport, Virginia.
• At L-6:30, teams evacuated the launch complex and went to a fallback area from where they supported the activation of the launcher. The Propellant Loading Sequencer was activated at L-6 hours followed by the initiation of Helium Flow to the vehicle.
• Five hours ahead of the planned T-0 time, the launch vehicle was powered up to begin extensive testing of all systems. Hard-line communications systems were verified and the vehicle went through S- and C-Band communications checks, Flight Termination System testing, telemetry verifications, payload checks as well as a Mission Simulation Test. At L-4:45, the Guidance and Navigation System of the vehicle was aligned and verified. Pre-Launch processing was started four hours before liftoff and the vehicle underwent more checks before the LOX Ground Support Equipment was chilled down ahead of fueling.
• At the same time, electrical testing wrapped up and the Flight Termination System underwent a final open loop test which has to be satisfactory for the vehicle to get approval for launch. The FTS can be used to destroy the vehicle in case of any major problems during ascent. At L-2:24, the ordnances of the ground and launcher were armed before, at L-2 hours, the Propellant Loading Operation got underway with the Chilldown of Liquid Oxygen Transfer lines and the LOX tank.
• Propellants started flowing inside the vehicle on time at L-90 minutes. At the start of propellant loading, the launch window was reduced to 15 minutes due to LOX constraints.
• A total of about 177,260kg of LOX and 64,740kg of Rocket Propellant-1, rocket-grade Kerosene, were loaded into the first stage of the vehicle. Antares’ first stage stands 27.6 meters tall and is 3.9 meters in diameter with a liftoff weight of 260,700kg. It was designed by Yuzhnoye and is built by Yuzhmash in the Ukraine.
• The countdown progressed inside L-10 minutes at which point the engine chilldown was switched to medium-flow to prepare the engines for ignition. The two AJ-26 engines deliver a total liftoff thrust of 332,400 Kilograms (3,260 Kilonewtons) to allow Antares to blast off with an initial thrust to weight ratio of 1.18.
• Two minutes before T-0, the first stage propellant tanks were pressurized to flight level as Fill & Drain Valves were cycled to the closed position. The two main engines were purged with Nitrogen to make sure no combustible gases were within the propellant lines to ensure the ignition sequence occurs as planned. 15 seconds before ignition, the two engines completed a short pre-launch slew profile test, at T-5 seconds, the Transporter, Erector and Launch Device (TEL) retracted, and at T-1.5 seconds, Antares completed a final health check. As clocks hit zero, the two engines ignited and throttled up to liftoff thrust – being monitored by flight computers to ensure both engines reached operational conditions. At T+1.5 seconds, the vehicle was committed to launch as commands to fire hold-down and propellant interface separation pyros were sent.
• Blastoff occurred at T+2 seconds, right at the opening of the launch window at 21:00:02.2 UTC and Antares started its historic demonstration mission – becoming the largest rocket to launch from Wallops Island. Four seconds after liftoff, Antares cleared the TEL and continued its vertical ascent until T+17 seconds at which point the vehicle started its pitch and roll maneuver to place itself onto its precise ascent trajectory. As the vehicle ascended, it passed Mach 1 at around T+1:09 and Maximum Dynamic Pressure at T+1:19.
• The first stage went through a pre-determined flight & attitude profile and continued to burn until T+3:50 with each AJ-26 providing 1,815 Kilonewtons of vacuum thrust at 108% of rated performance, starting a throttle down at T+3:24 in order to maintain structural limits. Following an on-time shutdown, the first stage was separated from the stack at T+3:55. The vehicle started a 89-second coast phase to gain altitude before firing the second stage in order to inject the vehicle into an orbit with sufficient perigee. Shortly after first stage separation, the Cold Gas Attitude Control System of the second stage was activated to keep the vehicle stable and maneuver the stack to the proper orientation for second stage ignition.
• Approaching the end of the coast phase, the vehicle jettisoned its Payload Fairing (T+5:19) and Interstage Adapter (T+5:24). The Reaction Control System was deactivated for these two events to prevent the fairing from re-contacting the vehicle as a result of inadvertent RCS firings. At T+5:28, the Castor 30A second stage ignited on its 136-second burn during which the Guidance System of the launcher provided energy management to correct any injection inaccuracies of the first stage by adjusting the second stage flight profile targeting a pre-programmed set of orbital parameters: 250 by 303 Kilometers at an inclination of 51.64 degrees.
• Castor 30A is 2.34 meters in diameter and 3.51 meters long. It has an empty weight of 1,220 Kilograms and can hold 12,815 Kilograms of propellant.
• The vehicle achieved a 237 by 258 Kilometer Orbit with an inclination of 51.61 degrees, showing a considerable error on Apogee and a small error on Perigee.
• At T+10:03, the heavily instrumented 3800-Kilogram Cygnus mass simulator was released into its orbit. Shortly before that, the four secondary payloads were released via two Poly Pico Orbital Deployers (P-PODs). The flight ended at T+18:44 after the second stage completed Contamination and Collision Avoidance Maneuvers.

Astrophilately covers:

Launch cancel Wallops Island. Credit: #421