Statement prepared by NASA November 1, 2016:

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 Sept. 1 mishap investigation will be incorporated into NASA's evaluation.

Independent advisory groups provide input on commercial crew safety considerations, among 

which the Aerospace Safety Advisory Panel is the primary independent adviser for commercial 

crew activity. Other groups, such as the ISS Advisory Committee, also seek information, and we 

treat all inquiries seriously. The ISS Advisory committee focuses on the International Space 

Station and international systems.
LT. GEN. THOMAS P. STAFFORD, USAF (Ret.) 

Chairman, NASA ISS Advisory Committee 

NAS~· Headq11arte,n 

Wullmlfoa., DC 20546 

l)e(;ember 9, 2015 

Mr. William Gerstenmaier 

Associate Administrator for Human Exploration and Operations 

National Aeronautics 8nd Space Adminis1ration 

300 E Street SW 

Washington, D.C. 20546 

Dear Mr. Gerstenmaier, 

We sincerely appreciated the briefing on the Commercial Crew Program from Kathy Lueders and Bill 

Jordan to our U.S. committee members. Thank you for making the briefing available to the committee. 

As is nonnal when the committee begins reviewing a topic, the briefing raised about as many questions 

as it answered. I will not list all the topics we will continue to follow, but there is one major issue that I 

believe deserves your careful attention. · 

There is a unanimous, and strong, feeling by the committee that scheduling the crew to be on board the 

Dragon spacecraft prior to loading oxidizer into the rocket is contrary to booster safety criteria that has 

been in place for over 50 years, both in this comttry and internationally. Historically, neither the crew 

nor any other personnel have ever been allowed in or near the booster dming fueling. Only after the 

booster is fully fueled and stabilized are the few essential people allowed near it. 

FurthenDore, in addition to the personnel risk, there is the risk of operating the engines outside their 

design input conditions. As an exp«ienced ''Prop" guy you know the problem here as well as anyone. 

Pump·.fed chemicil engines require a sufficient and consistent input pressure to reduce the likelihood of 

cavitation or mtsteady flow operations. We arc concerned that there may be insufficient precooling of 

the tank and plumbing with the current planned oxidizer fill scenario, and without recirculatiOn there 

may be stratification of oxidizer temperature that wiiJ cause a variation in the input conditions to the 

oxidizer pmnp. · 

In summary, we are deeply concerned about introducing the practice of fueling with the crew onboard, 

and about the lack of even a recirculation pump for oxidizer conditioning on Falcon 9. 

Thomas P. Stafford 

Lt. Gen., USAF (Ret.) 

Chairman 

NASA International Space Station Advisory Committee