Orbital’s Antares rocket is finally set to make its debut flight into space, following the approval of a launch window that opens on April 16. Dubbed the A-One mission, Antares will be tasked with a 603 second validation mission to loft a Cygnus mass simulator payload to a target orbit of 250 km x 300 km with an inclination of 51.6 degrees.
Antares road to Launch:
Orbital’s new medium class launcher was set to launch in 2012. However, the schedule was delayed several times, as the Mid-Atlantic Regional Spaceport (MARS) team at the Wallops launch site struggled with the completion of construction work on the pad’s propellant handling and pressurization systems.
Pressing ahead with the milestones, engineers conducted wet dress rehearsals – known as cold flow testing – ahead of the recent 7K hot fire test, as the rocket’s AJ26 engines roared into life, while the vehicle was held down at the launch pad.
The 27 second test fire proved to be successful, with a review of the results providing a green light to proceed towards the debut launch – a validation flight that will be the last major milestone ahead of the first Cygnus spacecraft mission to the International Space Station (ISS).
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Starting life under the name Taurus II, the Antares is the first cryogenically powered rocket to be produced by Orbital Sciences, and it’s also the largest rocket they have ever produced as well.
Antares will not only join Orbital’s well known fleet of rockets, but will also be the United States’ latest domestically produced launch vehicle. It’s important primary role – along with the Cygnus spacecraft – will be join forces with SpaceX’s Falcon 9 and Dragon duo, providing vital Commercial Resupply Services (CRS) to NASA and the ISS.
While SpaceX are currently in the midst of their second official CRS mission, Orbital first need to complete their COTS (Commercial Orbital Transportation System) milestones, ahead of being approved for what will be designated the “CRS-1 (OrB-1)” flight.
This will require two successful launches of the Antares, the first with a Cygnus mass simulator payload, to be followed by a second launch, this time with an actual Cygnus that will fly on a mission to the ISS under a similar scenario to that employed for SpaceX’s C2+ flight.
Orbital are currently targeting opportunities within a launch window that opens on April 16 and closes two days later.
Utilizing the countdown procedures used during Antares’ hot fire test, the AJ26’s will once again come to life, this time lifting the vehicle off Pad 0A at Wallops Island, Virginia.
The first stage will fire for approximately four minutes, propelling the launch vehicle to an altitude of approximately 113 kilometers, before staging takes place. The sequence calls for Main Engine Cut Off (MECO) at 230 seconds, followed five seconds later by 1-2 sep.
The second stage – or “upper stack” will continue the ride uphill, unpowered, with payload fairing separation scheduled for T+319 seconds at an altitude of 184 kilometers.
Ignition of the ATK Castor 30 solid rocket motor will occur at T+328 seconds into the mission, at an altitude of 189 kilometers – firing for a duration of just over two minutes, before burning out at an altitude of approximately 256 kilometers.
The stage will coast through to a mission elapsed time of 603 seconds, prior to spacecraft separation, completing the milestones for the A-One mission. However, a bonus element of the mission will see four small “pico satellites” deployed from two dispensers that will be integrated with the mass simulator.
Following a review of the mission parameters, Orbital will then press ahead to the next launch, this time on a mission to the orbital outpost.
This mission will be the key COTS validation flight, involving an Antares launch vehicle carrying a fully operational Cygnus spacecraft that will rendezvous and berth with the ISS to demonstrate the full capabilities of the cargo resupply system.
The Cygnus vehicle consists of an advanced Service Module and a Pressurized Cargo Module (PCM). The Service Module incorporates avionics, power and propulsion systems from Orbital’s flight-proven LEOStar and GEOStar satellite product lines.
Thales Alenia Space are providing Orbital with the pressurized modules for cargo missions to the ISS. The first PCM was followed by three more units in “standard” configuration, capable of transporting up to 2,000 kg of cargo each, along with five “enhanced” configuration units to follow, boosting payload capacity to 2,700 kg.
A large amount of planning for this mission has already been undertaken, such as several full simulation runs at Orbital’s mission control center, one of which can been seen in an exclusive video provided – with permission – to L2.
Like SpaceX’s C2+ validation mission with Dragon, ORB-D’s Cygnus will deliver actual cargo on its demo mission to the Station.
While the full list of cargo has not been finalized, ISS status notes (L2) recently spoke of two printer spares that have been designated to ride on Cygnus’ demo mission, showing ISS managers are keeping the new spacecraft’s debut run in the forefront of their upmass evaluations.
This involves the crew opening the hatch and removing the “top layers” on PORT and STBD pallets to make room in PCM. They will then be tasked with removing components of the Secondary Structure as required, ahead of emptying the FWD and AFT pallets to gain access to the Standoff pallets, which they will empty and repack.
The reverse sequence will be employed until the vehicle has been repacked, although all the return cargo won’t be classed as downmass, because – unlike Dragon – Cygnus won’t be returning to the ground or water.
Instead, it’ll be sent on a path to a destructive re-entry.
ORB-1 (CRS-1) Onwards:
Once the COTS requirements are satisfied, Antares will swap the Upper Stage from the Castor 30A to an upgraded version called the Castor 30B. This will be used for the CRS-1 (Orb-1) and CRS-2 (Orb-2) ISS runs under NASA’s Commercial Resupply Services (CRS) contract.
Orbital are already working the forward path requirements, recently ordering four additional Cargo Module Power Units (CMPUs) from Andrews Space, to be used to supply power to payloads aboard the CRS-1 (OrB-1) Cygnus. The CMPUs provide up to 150 Watts of 28VDC payload power to mid-deck locker payloads destined for the ISS aboard the Cygnus cargo vehicle.
For the last six CRS flights scheduled for the Antares, the transition towards the launch of extra cargo on a larger Cygnus Spacecraft will be enabled by ATK’s CASTOR 30XL Upper Stage motor, which is currently preparing for a static fire test.
The “enhanced” Cygnus is scheduled to fly the last five CRS missions, boosting payload capacity to 2,700 kg.
Under the CRS contract, Orbital will be delivering a total of 10 metric tons of cargo to the ISS.
(Images: via Orbital and L2’s Antares and Cygnus Section – containing presentations, videos, images, interactive high level updates and more, with additional images via Orbital).
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