Antares Rising: Orbital’s New Booster Joins NASA Line-Up

In a sign of growing confidence, NASA has accepted Orbital's Antares booster to compete for medium-class payload contracts. Image Credit: Orbital Sciences

Six months after gaining a new name, and only weeks before its scheduled maiden voyage, Orbital Sciences’ Antares rocket has been added to NASA’s Launch Services Contract (NLS-II), enabling it to bid for future missions to carry medium-class scientific payloads into orbit. The ‘on-ramp provision’ offers an annual opportunity for launch service providers not currently involved in NLS-II to compete for contracts to fly spacecraft weighing in excess of 550 pounds into minimum 124-mile circular orbits. As Orbital closes in on the first Antares launch in August and the first flight of its Cygnus cargo craft to the International Space Station in October-November, the move illustrates NASA’s confidence in the new rocket.

Coming hot on the heels of last month’s triumphant SpaceX Dragon mission, Orbital has much to prove in 2012. As NASA’s second Commercial Resupply Services partner, the Dulles, Virginia-based company – which celebrates its 30th anniversary this year – received a contract worth $1.9 billion in December 2008 and must execute a smooth flight of Antares and a full-up demonstration of Cygnus’ capabilities before it can progress with the first of eight manifested cargo missions. Achieving these targets have been problematic, and rocket and cargo carrier are both many months behind schedule, not least because of delays in building Antares’ launch pad and certifying its propellant handling facilities at the Mid-Atlantic Regional Spaceport (MARS) on Wallops Island, Virginia.

However, in recent weeks the rocket’s Aerojet-developed AJ-26 first stage engine has sailed smoothly through hot-fire tests at NASA’s Stennis Space Center in Mississippi. The AJ-26 has an interesting heritage: it is a rebuilt version of the Soviet NK-33 engine, originally conceived to power the ill-fated N-1 rocket to the Moon in the 1960s. Aerojet purchased 36 unused NK-33s from Russia in the mid-1990s, at a price of $1.1 million per engine, and subjected them to extensive performance enhancements and incorporated modern electronics. Fed by rocket-grade kerosene (known as ‘RP-1’) and liquid oxygen, the twin AJ-26s in Antares’ first stage will be complemented by a second stage, equipped with an Alliant TechSystems solid-fuelled motor and, eventually, by a hypergolic final stage. When fully operational, Antares has the capacity to deliver up to 15,000 pounds into low-Earth orbit, although last summer Aerojet partnered with Teledyne Brown to build a fully-US version of the AJ-26. This new engine will reportedly be capable of 500,000 pounds of thrust and may be a contender for NASA’s next heavy-lift booster, the Space Launch System (SLS).

Powered by two Aerojet AJ-26 engines in its first stage, Antares will have the capacity to deliver up to 15,000 pounds to low-Earth orbit. Photo Credit: Orbital Sciences/NASA

As Orbital’s rocket evolved, so too did its name. Until December 2011, Antares was known as ‘Taurus II’, but this nomenclature was changed in accordance with the company’s tradition of using Greek celestial names. As well as being one of the brightest stars in the sky, the reddish-coloured supergiant Antares also lent its name to the lunar module which carried astronauts Al Shepard and Ed Mitchell to the Moon’s surface on Apollo 14 in February 1971. Commenting on the change, Orbital President and CEO David Thompson remarked that “a launch vehicle of this scale and significance deserves its own name”.

That scale extends far beyond Cygnus and the fulfilment of the Commercial Resupply Services contract with NASA; Orbital has plans for Antares to deliver scientific, civilian government, military intelligence and commercial payloads into orbit. Certainly, NASA’s acceptance of Antares into the fold of its NLS-II contract carries great promise for the future of the rocket.

For now, Antares is very much linked in the public eye to Cygnus. In a sense, the first voyage of Orbital’s craft to the International Space Station, later this year, draws many parallels with the SpaceX Dragon. After launch, Cygnus will undertake a three-day rendezvous profile and perform numerous systems and functionality tests during final approach, before receiving authority to proceed within range of the Canadarm2 robotic arm for grappling and installation onto the nadir port of the Harmony node. Like Dragon – which will launch on its first ‘real’ delivery mission in early October – Cygnus is designed to spend about a month berthed at the International Space Station. Unlike its counterpart, though, it is not intended to survive re-entry and will be commanded to perform a destructive hypersonic dive into the atmosphere.

Dependent upon the performance of Antares during its first flight, and the performance of Cygnus itself, Orbital is contracted to deliver a total of 44,000 pounds of cargo to the station on its eight missions between 2012 and 2015. And it can be held in no doubt that NASA will be closely monitoring the new rocket’s fortunes in light of future NLS-II contracts.

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