Keith's note: SpaceX has field an amendment to their initial complaint about ULA. The amended complaint includes new information from a 20 June letter from Sen. John McCain to Under Secretary of Defense Frank Kendall. McCain's letter questions the lack of transparency around the cost of the Russian RD-180 engines that ULA currently uses for EELV launches.

- Text of SpaceX complaint amendment

- Text of McCain's letter

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"So neither the market nor the U.S. government gave RD Amross any reason to alter its business model. "ULA didn't get a gun to their head to make this deal," Keith Cowing, a former NASA astrobiologist and blogger at NASA Watch told Business Insider of ULA's use of a Russian-American joint venture as a rocket engine broker. "They do it willingly and openly, and the United States government sanctioned it. They're the sole supplier, they get to set the price, and we walk into this." But they're not really the sole supplier anymore. Whether McCain's accusations are true or not, SpaceX's entrance into competition for government launches would make RD Amross -- and business models based on an uninterrupted pipeline from foreign engine-builders to buyers in the U.S. government -- seem utterly outmoded."