Cygnus Orb-3

Orbital-3, also known as Orb-3, was an attempted flight of Cygnus, an automated cargo spacecraft developed by United States–based company Orbital Sciences, on October 28, 2014. The mission was intended to launch at 22:22:38 UTC that evening. This flight, which would have been its fourth to the International Space Station and the fifth of an Antares launch vehicle, resulted in the Antares rocket exploding seconds after liftoff.

This would have been the third of eight flights by Orbital Sciences under the Commercial Resupply Services (CRS-1) contract with NASA. This was the first attempted flight of the Antares 130, which uses a more powerful Castor 30XL second stage, and the last flight of the standard-sized Cygnus Pressurized Cargo Module.

In an Orbital Sciences tradition, this Cygnus spacecraft was named S.S. Deke Slayton after one of NASA's original Mercury Seven astronauts and Director of Flight Operations, who died in 1993. As the launch failed, the next spacecraft was also named after Deke Slayton.

The mission was scheduled to launch on October 27, 2014, at 22:45 UTC from the Mid-Atlantic Regional Spaceport at the Wallops Flight Facility in Wallops Island, Virginia, with rendezvous and berthing with the ISS early in the morning on November 2, 2014. This was the first night-time launch for both the Antares launcher and Cygnus spacecraft. The first launch attempt was scrubbed due to safety concerns of a sailboat entering the exclusion zone less than ten minutes before launch. A 24-hour delay was put in place, with the next launch opportunity scheduled for 22:22:38 UTC on October 28, 2014.

The Antares rocket carrying the Orb-3 Cygnus launched as scheduled from Launch Pad 0A on October 28, 2014. Fifteen seconds after liftoff a failure of propulsion occurred in the first stage. The vehicle began falling back to the launch pad and the Range Safety Officer engaged its flight termination system just before impact.

The resulting explosion was felt in Pocomoke City, Maryland, 20 miles (32 km) away. The fire at the site was quickly contained and allowed to burn itself out overnight. Initial review of telemetry data found no abnormalities in the pre-launch, the launch sequence, and the flight, until the time of the failure.

In a press release, NASA stated that there were no known issues prior to launch and that no personnel were injured or missing but that the entire payload was lost and there was significant damage to the launch pad. On October 29, 2014, teams of investigators began examining debris at the crash site, while a survey the same day found that there was no serious damage to the launch pad and site fuel tanks, although repairs would be required.

Subsequent investigation found that the LOX turbopump had exploded, which in turn, caused a shock wave that severed surrounding propellant lines and started a fire from leaking fuel. The fire damaged various components in the thrust section leading to the engines gradually being shut down, although a specific reason for the failure could not be determined. Possible causes were a defective pump bearing, ingestion of loose debris, or a manufacturing defect.