Orbital set May 6 for next Cygnus mission to the ISS

by Chris Bergin

The next launch of Orbital’s Cygnus spacecraft has been targeted for a No Earlier Than (NET) launch target of May 6. The CRS-2/ORB-2 mission will be launched by the company’s Antares rocket from the Mid-Atlantic Regional Spaceport at NASA Wallops in Virginia – the fourth launch of Orbital’s new medium class rocket, providing the ride uphill for Cygnus’ third trip to the orbital outpost.


Antares has enjoyed a flawless opening salvo of launches, beginning its career with the A-ONE test launch in 2013.

Just a few months after its debut, Antares launched again, this time with the first operational Cygnus spacecraft as its passenger.

Z77The ORB-D1 mission saw Cygnus make her first journey to the International Space Station, achieving top marks on the Commercial Orbital Transportation Services (COTS) program scorecard.

This allowed the Orbital duo to begin Commercial Resupply Services (CRS) operations, with the CRS-1/ORB-1 Cygnus berthing with the ISS, following its successful ride atop of the third Antares rocket.

ORB-1 delivered 1,466 kilograms (3,232 lb) of upmass, out of a maximum of 2,000 kg (4,400 lb), before being unberthed and released by the Space Station Remote Manipulator System (SSRMS) on February 18.

As with all Cygnus missions, the spacecraft – full of Station trash – completed her service with a fiery re-entry.

The next mission, CRS-2/ORB-2 now has a firm launch date, following Orbital’s announcement on Wednesday.

With agreement between Orbital, Range assets and NASA, Antares will set sail at 3:44 pm (EDT) – the beginning of a 5-minute launch window that extends to 3:49 pm (EDT) – on May 6.

Z5At the completion of the ORB-2 mission, Orbital’s system will have delivered approximately 3,800 kilos (about 8,400 lbs) of cargo to support the Expedition crews conducting research and living aboard the ISS.

Antares’ ORB-2 mission will utilize the Castor 30B upper stage, which – during the ORB-1 launch – replaced the less powerful Castor 30A used for the previous two Antares missions.

The 30B will itself be replaced after the upcoming launch with an even more capable Castor 30XL.

Orbital originally intended to switch to a liquid upper stage called the HESS, utilizing the Russian RD-0124. However, the company later decided to go with a stretched version of the original solid-based Upper Stage, built by another industry stalwart, ATK.

The CASTOR 30XL will also allow for the eventual transition towards the launch of extra cargo on a larger Cygnus Spacecraft. The “enhanced” Cygnus is scheduled to fly the last five CRS missions, boosting payload capacity to 2,700 kg.

Screenshot from L2 video of CASTOR 30XL static fireThe CASTOR 30XL solid rocket motor is 92 inches in diameter, 236 inches in length and weighs approximately 58,000 pounds.

The nozzle is eight feet long with a submerged design with a high performance expansion ratio (56:1) and a dual density exit cone well suited for high altitude operation.

According to L2 information, ATK have wasted little time since test firing the test motor at the Arnold Engineering Development Center in Tennessee in 2013, with three CASTOR 30XLs constructed and ready to be used by Orbital.

CASTOR 30XLAll that after an expedited test program that took only two years to get to the test fire stage.

“In less than two years the ATK team has designed and built the static test article for a new commercial product that will significantly improve the performance of Orbital’s Antares launch vehicle,” noted John Slaughter, vice president of Commercial Programs for ATK’s Defense and Commercial Division at the time.

With the ISS now extended to a lifetime that will reach into at 2024, Orbital – and the other CRS partner, SpaceX – are likely to be the front runners for a second round of CRS contracts.

Z3132Known as CRS2, this second round will cover services from 2017 through 2024, with the NASA RFI noting the Agency may elect to have one contract or multiple contracts to meet the requirements.

The document also notes the Agency expects to allocate between $1.0B and $1.4B per year to facilitate these services.

CRS2 outlines call for the delivery of 14,250 to 16,750 kilograms (kg) of pressurized cargo, along with 1,500 to 4,000 kg of unpressurized cargo per year.

SpaceX’s Dragon will be the next CRS mission to the Station, with a current target of March 30 for CRS-3/SpX-3, a delayed launch date after contamination was found on blankets in the trunk section.

The root cause and forward plan are currently being evaluated with specific details of the cause – provided to L2 – currently awaiting a response from SpaceX officials.

(Images: L2, ATK and Orbital)

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