WASHINGTON — A generally positive outside review of the two firms under contract to deliver cargo to the international space station (ISS) contained strong concerns about software development procedures at Space Exploration Technologies Corp. (SpaceX) — concerns the company and the head of a NASA safety panel said have since been addressed.

The software concerns were mentioned in a recently released summary of an Aug. 9 meeting of NASA’s ISS Advisory Committee and the Aerospace Safety Advisory Panel held with SpaceX and Orbital Sciences Corp. at Johnson Space Center in Houston to review progress on the firms’ rival space station cargo vehicles.

“SpaceX is entrepreneurial; their thinking is a fresh approach … However, their comments with regard to software were very disturbing and presented a lack of insight and sophistication in what can go wrong in this business,” the summary states. Thomas Stafford, the retired Apollo astronaut who chairs the ISS Advisory Committee, submitted the summary to Congress as part of his Oct. 12 testimony before a House Science, Space and Technology subcommittee hearing on ISS safety.

“The SpaceX software presentation was unsettling to the review team,” the summary continues. “There was no Capability Maturity Model Integration (CMMI) accredited capability or process, and the software chief [at SpaceX] said he didn’t worry about errors because ‘there were no mistakes in the software.’ In the Review Team’s experience, this is unlikely.”

Joseph Dyer, the chairman of the Aerospace Safety Advisory Panel, said in an Oct. 19 phone interview that since the August meeting, “we’ve had the strongest assurance from SpaceX that [software] will be an item of special attention.”

Dyer added that “there’s been a lot of good discussion between NASA, SpaceX and [the Aerospace Safety Advisory Panel]” and that the software concerns raised in August were now “the farthest from my mind.”

“There was clearly a miscommunication,” SpaceX spokeswoman Kirstin Grantham said Oct. 20 about the August meeting at Johnson. “The ISS safety and mission assurance team has approved our software development processes [and] NASA engineers have access to SpaceX software to conduct their own detailed reviews.”

A NASA space station official said Oct. 20 the agency has the appropriate safeguards in place for future cargo deliveries to the international space station.

“NASA has been working with SpaceX on their overall software development processes, the software architecture, and both stand alone and integrated NASA and SpaceX software testing,”  Kathy Lueders, manager of the International Space Station Transportation Integration Office, wrote in an Oct. 20 email to Space News. “SpaceX has not yet passed all of the software milestones but these are planned. SpaceX will show compliance to all of the software requirements prior to the demonstration mission.”

SpaceX aims to launch the Dragon cargo vehicle on a demonstration flight to the international space station as soon as late December, but the company’s chief executive, Elon Musk, recently acknowledged the flight likely would slip into early 2012. Orbital Science’s demonstration flights also have slipped into 2012 (see related story above).

After SpaceX and Orbital demonstrate their spacecraft, the companies can begin hauling cargo to the space station. SpaceX’s $1.6 billion cargo resupply services contract is for 12 flights to ISS. Orbital’s contract, worth $1.9 billion, calls for eight flights.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.