posted 03-09-2016 08:13 AM               

Please use this topic to discuss Orbital ATK's OA-6 Cygnus resupply flight to the International Space Station. The S.S. Rick Husband is launching on a United Launch Alliance Atlas V rocket from the Cape Canaveral Air Force Station in Florida.

posted 03-24-2016 08:36 AM               

The RD-180 main engine, powering its 68th Atlas, concluded its firing just over four minutes after liftoff. But it shut down about five seconds prematurely compared to pre-flight predictions, robbing the flight plan of the durable thrust — and speed — for the final five seconds of the first stage burn.

The core stage separated and the RL10C engine of Centaur was ignited to produce 22,900 pounds of thrust. It was supposed to be a burn lasting just shy of 14 minutes to heave the payload into the targeted orbit.

With the first stage performance shortfall, however, the Centaur ended up firing for 15 minutes to get Cygnus where it wanted to go.

...United Launch Alliance is not taking the situation lightly. It is studying the data to figure out root-cause of the first stage shortfall and determine what, if anything, needs adjusted before the next launch.

posted 03-31-2016 01:10 PM               

ULA successfully launched and deployed the OA-6 Cygnus spacecraft to its desired orbit on Tuesday, March 22. During the launch, the system experienced a premature first stage shutdown. The first stage cut-off occurred approximately 6 seconds early; however the Centaur automatically compensated by burning longer. The robustness of the system achieved mission success, delivering Cygnus to a precise orbit as planned.

The ULA engineering team is continuing to review the data and has developed initial fault trees with our industry partners. The team has been successful in isolating the anomaly to the first stage fuel system and its associated components.

Per standard processes when a flight anomaly such as this has been identified, ULA and our partners have formed a robust review team with full collaboration with major customers. The review will thoroughly assess all flight and operational data to determine root cause and identify appropriate corrective actions prior to future flights.

posted 04-08-2016 06:37 PM               

The Atlas V MUOS-5 launch is delayed and indefinite on the Eastern Range due to ongoing evaluation of the first stage anomaly experienced during the OA-6 mission.

ULA successfully delivered the OA-6 Cygnus spacecraft to the International Space Station (ISS) on March 22. The MUOS-5 spacecraft and launch vehicle are secure at their processing facilities.

posted 04-29-2016 08:55 AM               

ULA successfully delivered the OA-6 Cygnus spacecraft to its precise orbit as planned on March 22. During the launch, the system experienced a premature first stage shutdown. Atlas is a robust system. The Centaur upper stage compensated for the first stage anomaly, delivering Cygnus to a precise orbit, well within the required accuracy.

The ULA engineering team has reviewed the data and has determined an anomaly with the RD-180 Mixture Ratio Control Valve (MRCV) assembly caused a reduction in fuel flow during the boost phase of the flight. In addition to analysis and testing, all RD-180 engines are being inspected.

Last Friday, in preparation for the MUOS-5 launch, the Atlas V completed the Launch Vehicle on Stand (LVOS) operation, erecting the Atlas V into the Vertical Integration Facility at Cape Canaveral Air Force Station. LVOS will allow configuration of the vehicle to support RD-180 engine inspections and confirm all engine components are ready for launch.

The Atlas V MUOS-5 launch is targeted for early summer; a new launch date has not been secured on the Eastern Range. The impact to the remainder of the Atlas V manifest is in review with new launch dates being coordinated with our customers. All missions manifested for 2016 are expected to be successfully executed by the end of the year, including OSIRIS-REx, which will remain in early September to support its critical science window.