NASA’s safety advisory panel discussed SpaceX's proposal of loading rocket propellants when astronauts are aboard. It seems to be a reasonable option in place of the group. Members of the Aerospace Safety Advisory Panel have maintained that loading crew the even before fueling is done is viable. However, the possible hazards need to be controlled.
According to Brent Jett (Retired Captain) of the panel, if the controls can be decided on and implemented for causes of hazard and situations which could end in an emergency, loading and going is an option to be considered. Boeing Co. and SpaceX have contracts from NASA contracts to manufacture crew capsules. These will be used for the transportation of astronauts to ISS (International Space Station). SpaceX and Boeing are supposed to carry out test flights in August and flight tests (with crew) another few months later.
The rocket fueling process of SpaceX has been subjected too much deliberation since the issue cropped up during a meeting in the House Committee on Science, Space and Technology. SpaceX makes use of liquid oxygen (super chilled). This maximizes the amount which can be contained in the tank, thus increasing the rocket's power during liftoff. The super cold temperature implies that the fuel must be kept right before the launch. Hence in case of crewed flights, astronauts would already be onboard.
A Falcon 9 rocket of SpaceX had exploded on a launch pad in 2016. The rocket propellant was being loaded then. This explosion damaged the pad and destroyed the SpaceX’s communication satellite. On further investigation, SpaceX discovered that the tank had most likely failed since the chilled liquid oxygen had collected in some buckles used onboard the vehicle. "Breaking fibers or friction" had then ignited the oxygen present in the carbon overwrap, according to the company. SpaceX redesigned its pressure vessels. NASA then began an intensive test program to examine the vessels’ behavior under cold temperatures.
Previously, astronauts boarded the vehicle only after the propellant had been loaded. The Safety Advisory Panel had previously warned about the method proposed by SpaceX in a previous report. Saying, according to the panel, the associated risks of this method had not been understood. However, SpaceX believes that the faster fuel-loading process is preferable and safer when compared to traditional methods as it lessens the time of the crew’s exposure to a fuel-loaded rocket. It has also created an abort system to carry astronauts to safety, if an explosion takes place.