Orbital Sciences has announced comprehensive plans to fulfill its contract commitments under NASA's Commercial Resupply Services (CRS) program as well as to accelerate an upgrade of the Antares medium-class launcher's main propulsion system.

Under the new approach and in line with Orbital's existing CRS contract, all remaining cargo will be delivered to the International Space Station (ISS) by the end of 2016. There will be no cost increase to NASA and only minor adjustments will be needed to the cargo manifest in the near term.

Orbital's Antares launch failure Accident Investigation Board (AIB) is making good progress in determining the primary cause of last week's failure. A preliminary review of telemetry and video data has been conducted and substantial debris from the Antares rocket and its Cygnus payload has been collected and examined.

While the work of the AIB continues, preliminary evidence and analysis conducted to date points to a probable turbopump-related failure in one of the two Aerojet Rocketdyne AJ26 stage one main engines. As a result, the use of these engines for the Antares vehicle likely will be discontinued.

To maintain the CRS program's critical ISS supply line, Orbital plans an early introduction of its previously selected Antares propulsion system upgrade in 2016. This will be preceded by one or two non-Antares launches of the company's Cygnus cargo spacecraft to the ISS in 2015-2016, employing the spacecraft's compatibility with various launch vehicles and its flexibility to accommodate heavier cargo loads as launcher capacity permits.

In addition, the company expects repairs to the Mid-Atlantic Regional Spaceport (MARS) launch complex at NASA's Wallops Flight Facility to be undertaken quickly, allowing launch operations to continue at Wallops Island with the upgraded Antares beginning in 2016.

"Orbital is taking decisive action to fulfill our commitments to NASA in support of safe and productive operations of the Space Station. While last week's Antares failure was very disappointing to all of us, the company is already implementing a contingency plan to overcome this setback.

"We intend to move forward safely but also expeditiously to put our CRS cargo program back on track and to accelerate the introduction of our upgraded Antares rocket," said Mr. David W. Thompson, Orbital's Chairman and Chief Executive Officer.

"Exact financial impacts to Orbital will depend on which of several specific options for near-term launches is selected, but they are not expected to be material on an annual basis in 2015. In all cases, no significant adverse effects are projected in 2016 or future years, in part because the cost of the Antares propulsion system upgrade was already part of our internal investment plan during that time," he added.

"We very much appreciate the tremendous support Orbital has received from NASA and Virginia's MARS commercial spaceport team over the last seven years on our Antares rocket and CRS cargo programs. We look forward to working closely with them to quickly recover from last week's setback," Thompson concluded.