The US company Kistler Aerospace worked on incorporating these engines into a new rocket design with the intention of offering commercial launch services, but the attempt ended in bankruptcy. Aerojet also modified the NK-33 to incorporate thrust vector control capability for Orbital Science's Antares launch vehicle. Antares used two of these modified AJ-26 engines for first stage propulsion. The first four launches of the Antares were successful, but on the fifth launch the rocket exploded shortly after launch. Preliminary failure analysis by Orbital pointed to a possible turbopump failure in one NK-33/AJ-26. Given Aerojet's previous problems with the NK-33/AJ-26 engine during the modification and test program (two engine failures in static test firings, one of which caused major damage to the test stand) and the later in-flight failure, Orbital decided that the NK-33/AJ-26 was not reliable enough for future use.