Lt. Gen. Tom Stafford (Ret.) and other members of NASA’s International Space Station (ISS) Advisory Committee are worried about a proposal by SpaceX to fuel its Falcon 9 rocket while crews are aboard when it conducts commercial crew launches. The committee was made aware of the SpaceX proposal last year and wrote a letter to the head of NASA’s human exploration program, Bill Gerstenmaier, expressing concern, but has not received a reply. The September 1 incident in which a SpaceX vehicle caught fire and exploded during fueling has accentuated the committee’s concerns.

Stafford is a very highly respected former astronaut who flew on Gemini and Apollo missions, including commanding the U.S. portion of the U.S.-Soviet 1975 Apollo-Soyuz Test Project (ASTP). He chairs the ISS Advisory Committee, which is chartered to assess all ISS aspects related to safety and operational readiness, utilization and exploration. The committee also meets as a joint commission with its counterparts on the Roscosmos state space corporation’s Advisory Expert Council.

At the end of its public meeting at NASA on Monday, committee member Joe Cuzzupoli raised the Space X issue. He asked Stafford if the committee had received a response from Gerstenmaier, especially considering the fire and explosion that destroyed a SpaceX Falcon 9 rocket and the Amos-6 satellite during a routine pre-launch on-pad test on September 1. Cuzzupoli has many decades of industry experience in designing and building rockets dating back to the Apollo-Saturn and space shuttle programs.

Stafford noted that the committee first learned of the SpaceX proposal at a briefing last December by Kathy Lueders, NASA’s program manager for the commercial crew program. Lueders told the committee that SpaceX wants crews strapped into their seats before the Falcon 9 rocket is loaded with superdensified chilled oxygen, which would happen just 30 minutes before launch. Stafford said committee members were “unanimous” in opposition because no one should ever be near the pad when fueling takes place, which is true internationally. On December 9, he wrote a letter to Gerstenmaier, NASA’s Associate Administrator for Human Exploration and Operations, expressing those concerns.

The committee was briefed again by Lueders in February 2016 and “she said she would get back to us,” Stafford continued. She had not done so by August, however, so he called Gerstenmaier who promised the committee another briefing within two months.

That call was just days before the September 1 incident, he said. NASA has not provided the committee with any further information, but Stafford said he expects a briefing at the committee’s next

meeting in December in Houston, asserting that “our letter hit the nail on the

head that this is a hazardous operation.”

SpaceX is still trying to determine the root cause of the fire, but believes it is associated with helium loading conditions in one of three composite overwrapped pressure vessels (COPVs) in the second stage liquid oxygen tank. SpaceX noted that no one was injured: “Per standard operating procedure, all personnel were clear of the pad.”

Falcon 9 is used for launches of commercial satellites like the Amos-6 communications satellite that was destroyed on September 1, as well as commercial cargo launches of its robotic Dragon spacecraft for NASA to support ISS. It is developing a version of Dragon to take astronauts to and from ISS called Crew Dragon. It has an integrated abort system that would propel the crew capsule away from the rocket in an emergency. It can operate at any point during launch and ascent, including on the pad. SpaceX conducted a pad abort test of the system last year.

SpaceX founder and CEO Elon Musk said via Twitter (@elonmusk) the day of the incident that if a Dragon had been on top of the rocket, it “would have been fine.”

@scrappydog yes. This seems instant from a human perspective, but it really a fast fire, not an explosion. Dragon would have been fine. — Elon Musk (@elonmusk) September 1, 2016

SpacePolicyOnline.com asked NASA for a copy of the letter Stafford sent to Gersternmaier immediately after Monday’s meeting, but has not received a reply. Separately, however, NASA sent the following statement via email:

“Spacecraft and launch vehicles designed for the Commercial Crew Program must meet NASA’s safety and technical requirements before the agency will certify them to fly crew. The agency has a rigorous review process, which the program is working through with each commercial crew partner.

“Consistent with that review process, NASA is continuing its evaluation of the SpaceX concept for fueling the Falcon 9 for commercial crew launches. The results of the company’s mishap investigation will be incorporated into NASA’s evaluation.”

Editor’s Note: NASA released the letter on November 4.