SpaceX is facing a potential roadblock in its path to sending astronauts to the International Space Station as part of NASA’s Commercial Crew program. Yesterday, Lt. Gen. Tom Stafford, a veteran astronaut who flew during the Gemini and Apollo eras, and who happens to be chair of the ISS Oversight Panel, an independent safety committee with purview over all things ISS, raised strong objections to SpaceX’s plans to fuel the Falcon 9 with the crew already aboard.
“It was unanimous … Everybody there, and particularly the people who had experience over the years, said nobody is ever near the pad when they fuel a booster,” Stafford said, referring to an earlier briefing the group had about SpaceX’s proposed fueling procedure. (spacepolicyonline).
Presciently, Stafford had written a letter to Bill Gerstenmaier, NASA’s Associate Administrator for Human Exploration and Operations on December 9th 2015 expressing the uniform objection to SpaceX’s plan of action. As currently formulated, that plan would see astronauts enter the Dragon 2.o and strap themselves in 30 minutes before fueling of the rocket begins.
Those objections took on added gravity following the September 1st ‘anomaly’ which saw a Falcon 9 explode on the pad during fueling operations for a pre-flight test. Oddly enough, according to the report of the meeting provided by Marcia Smith, Stafford had called Gerstenmaier the day before the incident because NASA had not officially responded to his letter.
It remains to be seen whether or not SpaceX will substantially change its fueling procedures for the Falcon 9 to accommodate those concerns for crewed flights, and it may not even be practical to do so. The current Falcon 9 depends depends on last minute loading of super-cold propellants to achieve maximum density and performance, and the current iteration Merlin engines have been configured to operate in those conditions. A switch back to previous procedures could be problematic.
While Stafford’s objections come from a long and storied background, as well as what is standard practice throughout the launch industry, there is another aspect to the situation. The September 1st SpaceX pad explosion marked the first time such an event has occurred while fueling a launch vehicle in the U.S. since the earliest days of the space age. It was in that regard, a truly rare instance, but that does not make it the only one possible.
Had astronauts, as well as any ground personnel assisting them, been in the process of boarding the Dragon, or any other crew vehicle sitting atop a fully fueled rocket at the moment a similar incident took place, they would not have survived. It is a brief but unavoidable window of risk which comes with what has thus far been standard practice.
Consider this excerpt from NASA’s Apollo history audio of the countdown to Apollo 11:
“The spacecraft Commander Neil Armstrong and the Command Module Pilot Michael Collins now proceeding across the swing arm into the small white room that attaches at the spacecraft level. In the meantime, about 100 feet below, we have a technician – a team of technicians working on a leaking valve which is a part of the Ground Support Equipment, a part of the system that’s used to replenish the fuel supply for the third stage of the Saturn V rocket. He is proceeding to tighten a series of bolts around this valve in the hope that this will correct the leak. Once the technicians do depart, the hydrogen will again be flowed through the system to assure that the leak has been corrected.”
While NASA took every practical precaution, the astronauts and technicians were clearly very exposed to the risk, no matter how remote, of working on and around, a fully fueled Saturn V.
On the other hand, after boarding an empty rocket in comparative safely, a launch pad emergency, even one as energetic as what took place with the Falcon 9, would still see the crew, secured within their spacecraft, have an excellent chance of survival due to the emergency escape system and a pad abort procedure which has already been successfully demonstrated.