I am writing to correct the record on the cost of development of the Falcon 9 launch vehicle and Dragon spacecraft. In a letter printed on Jan. 24 [“Understating the Cost of SpaceX’s Success,” page 18], Joseph W. Hamaker, a senior cost analyst for SAIC, makes erroneous guesses about Space Exploration Technologies Corp. (SpaceX) expenditures to date, and concludes that “playing with these numbers and being as optimistic as I dare results in costs of well over $1 billion for Falcon 9/Dragon — probably more like $1.5 billion.”