Two weeks ago, for a moment it looked as if Aerojet Rocketdyne stood a fair shot at walking away with United Launch Alliance for something close to its $2 billion dollar unsolicited offer. Had the deal gone through, Aerojet would have presumably been in a much stronger position to secure government funding for its AR-1 engine, which the company hoped to pair up with the Atlas V to replace the controversial Russian built RD-180. Instead, Boeing crashed the party last week when company execs announced that not only was the offer not being accepted, it was not even being taken seriously.
That news came as Blue Origin announced that is proceeding with a new Florida based rocket plant for a booster which will employ that company’s BE-4 methane engine. It is the same engine which ULA is prioritizing over Aerojet’s AR-1, and the Blue Origin commitment to the BE-4 for its own purposes had the side of effect of weakening Aerojet’s standing. That was bad enough, but yesterday ULA announced that it is dropping Aerojet’s solid rocket strap-on boosters currently employed on the Atlas V, for an alternative motor which will be supplied by Orbital ATK. Furthermore, the change will happen fairly quickly in launch contract terms, beginning in late 2018 for Atlas and continuing after that with the Vulcan booster now in early development.
Aerojet designates the Atlas V Solid Rocket Motor as the AJ-60A, saying on its website:
“The motor is configured with a thrust profile that reduces aerodynamic loads during max-Q and thrust-differential during tail-off. It can be configured for other applications that require a different case length and/or attach interface requirement. It could also be used as an in-line stage for small launch vehicles or strategic missiles.
The composite graphite fiber and Aramid-filled EPDM insulation monolithic motor case has no segmented joints, thus eliminating historical failure modes and provides functional and operational simplicity. At 62” in diameter and 669” in length, it is the largest monolithic motor currently in production in the world.”
Orbital ATK currently supplies United Launch Alliance the GEM-60 (Graphite Epoxy Motor) motor for two versions of the Delta IV Medium booster. With the advent of the new Vulcan rocket, Orbital ATK will now upgrade the SRB’s to a 63 diameter version.
While the switch for Atlas is being presented as a cost savings move, and has been in the works for some time as ULA struggles to compete with SpaceX on price, the timing of the announcement may also be a polite “up yours” in response to the dismissed bid for the entire company. Alternatively, if Aerojet knew the change was coming, that awareness might have proven to be an important factor in the decision to make a play for ULA in the first place. With the RS-68 main engines going out with the soon to be discontinued Delta series, the unfunded AR-1 in a poor competitive position versus the BE-4, and Orbital ATK having going to the Russian built RD-181 for the new version of Antares, there was in retrospect, little left to lose in the effort.