In a blog posted May 31 on, defense consultant Loren Thompson launches a second lengthy critique of Space Exploration Technologies Corp. (SpaceX), saying the upstart commercial launch services company has yet to establish a track record for reliability and is basing its pricing claims on dubious market assumptions.

Less than a month ago, Thompson, chief operating officer of the Lexington Institute, went after SpaceX and its founder, Internet tycoon Elon Musk. His original blog, posted May 5 on the Lexington Institute’s website, was entitled: “SpaceX: Glib Salesman Takes NASA for a Ride.” republished the piece May 23.

SpaceX fired back with its own commentary the next day, painting Thompson as a shill for Lockheed Martin and characterizing the Lexington Institute as the “defense industry’s pay-for-play ad agency.”

In his latest blog, Thompson addresses these criticisms, including the fact that he does consulting for Lockheed Martin, a parent company to United Launch Alliance whose U.S. government business is being targeted by SpaceX.

    “[S]ome readers were incensed by my criticism of SpaceX, the best known of the new commercial launch companies. Several, including SpaceX spokesman Robert Block, submitted comments alleging that my post was incomplete, misleading, or motivated by my business relationships with other launch companies such as Lockheed Martin.

     “I plead guilty to the charge that the piece was incomplete — I had much more research material than could reasonably be fit into a single blog posting. This week’s commentary will provide some of that additional material, since it speaks to the points raised by my critics.”