Orbital ATK "Return to Flight" launch of the re-engined space rocket cargo mission was delayed for a month mainly because of the need for a more detailed analysis of the modified booster.

"Orbital ATK is currently working with NASA to target a window in the second half of September for the launch of the OA-5 mission. A more specific launch date will be identified in the coming weeks," an Orbital ATK official said in a statement.

The commercial space flight company, Orbital ATK announced the delay of the launch two weeks before the supposed liftoff. The launched that was moved to mid of September was originally scheduled on Aug. 22 from the company's launch pad at Virginia Space's Mid-Atlantic Regional Spaceport (MARS) Pad OA at NASA's Wallops Flight Facility.

The Antares 230, Orbital ATK's spacecraft is a medium-class commercial launch rocket was modified in order to upgrade the engine to the first stage Russian-built RD-181 engines. The Russian RD-181 engines will have to be fully validated by NASA before it executes its mission to the International Space Station (ISS).

"Due to a variety of interrelated factors, including the company's continuing processing, inspection and testing of the flight vehicle at Wallops Island, and NASA's scheduling of crew activities on the International Space Station in preparation for upcoming cargo and crew launches, Orbital ATK is currently working with NASA to target a window in the second half of September for the launch of the OA-5 mission," an official from Orbital ATK announced in a statement.

NASA's validation of all incoming and outgoing missions to the ISS is vital to guarantee the smooth execution and delivery of supplies and experiment equipment to the ISS.

Orbital ATK Antares is tasked to carry OA-5 Cygnus need to undergo review before being sent to the ISS. The current OA-5 launch will carry 5,290 lbs (2,400 kg) of cargo, supplies for the crew and experiment equipment to the ISS.