Antares, known during early development as Taurus II, is an expendable launch system developed by Orbital Sciences Corporation. Able to launch payloads heavier than 5,000 kg (11,000 lb) into low-Earth orbit, it made its inaugural flight on April 21, 2013. Designed to launch the Cygnus spacecraft to the International Space Station as part of NASA’s COTS and CRS programs, Antares is the largest rocket operated by Orbital Sciences.
The NASA COTS award was for US$171 million and Orbital Sciences expected to invest an additional $150 million, split between $130 million for the booster and $20 million for the spacecraft. As of April 2012, development costs were estimated at $472 million. The total cost of the rocket is well over $200M, not including the destruction to property.
The first stage uses RP-1 (kerosene) and liquid oxygen (LOX) as propellants, powering two Aerojet AJ-26 engines, which are modified Soviet-built NK-33engines. Together they produce 3,265 kilonewtons (734,000 lbf) of thrust at sea level and 3,630 kN (816,100 lbf) in vacuum. As Orbital has little experience with large liquid stages and LOX propellant, some of the Antares first stage work was contracted to the Ukrainian Yuzhnoye SDO, designers of the Zenit series. The core provided by Yuzhnoye includes propellant tanks, pressurization tanks, valves, sensors, feed lines, tubing, wiring and other associated hardware.
“During hot-fire testing earlier at NASA’s Stennis Space Center, Aerojet Rocketdyne’s AJ26 engine experienced a test anomaly. There were no injuries,” noted Aerojet Rocketdyne spokesperson Jessica Pieczonka to NASASpaceflight.com. A previous failure of an AJ-26 occurred in June, 2011 – when the fourth Antares engine caught fire on the E-1 Test Stand. The fire was caused by a kerosene fuel leak in an engine manifold, with the root cause was subsequently determined to be stress corrosion cracking of the 40-year old metal. First stage failure was confirmed with the initial conference call to the press, which can be heard below.
Like Zenit, the Antares vehicle has a diameter of 3.9 m (150 in) with a matching 3.9 m payload fairing. The fairing is manufactured by Applied Aerospace Structures Corporation of Stockton, California, which also builds other composite structures for the vehicle, including the fairing adaptor, stage 2 motor adaptor, stage 2 interstage, payload adaptor, and avionics cylinder.
The second stage is a solid-fuel rocket, the Castor 30. Developed by ATK as a derivative of the Castor 120 solid stage, the Castor 30B produces 293.4 kN (65,960 lbf) average and 395.7 kN (88,960 lbf) maximum thrust, and uses electromechanical thrust vector control. The first two flights of Antares used a Castor 30A, followed by two flights of the Antares 120 using an enhanced Castor 30B. The longer Castor 30XL second stage will be used on subsequent ISS resupply flights, allowing Antares to carry larger Enhanced Cygnus.
Orbital Sciences offers two optional third stages, the Bi-Propellant Third Stage (BTS) and an ATK Star 48-based third stage. BTS is derived from Orbital Sciences’ GEOStar spacecraft bus and uses nitrogen tetroxide and hydrazine for propellant; it is intended to precisely place payloads into their final orbits. The Star 48-based stage uses a Star 48BV solid rocket motor and is planned to be used for higher energy orbits.
The October 28th flight was the first Antares launch to use Castor 30XL upper stage; payload included a Planetary Resources Arkyd-3satellite and a NASA JPL/UT-Austin CubeSat mission named RACE. The Antares rocket encountered an anomaly about 6 seconds into the mission leading to the explosion of the rocket and loss of the payload.
Since NASA is a publicly funded company, the details of the conference call is offered to you below. As the recording below states, Root Cause Analysis will be conducted. If anyone in the area locates an “Unknown Object” report it to the Incident Response Team at 757-824-1295. For more information visit www.NASA.gov