NASA’s Commercial Crew Program and SpaceX are finalizing plans for launch day operations as they prepare for the company’s first flight test with astronauts on board. The teams are working toward a crew test flight to the International Space Station, known as Demo-2, with NASA astronauts Bob Behnken and Doug Hurley in April 2019. In preparation for this test flight, SpaceX and NASA will continue to complete and review the important analyses and tests leading to launch.
A key question the program and the company have been assessing is whether the astronauts will climb aboard the Crew Dragon spacecraft before or after SpaceX fuels the Falcon 9 rocket. NASA has made the decision to move forward with SpaceX’s plan to fuel the rocket after the astronauts are in place. While the agreement makes this plan the baseline for operations, it is contingent upon NASA’s final certification of the operation.
SpaceX is continuing to test and qualify many of the systems and components of the Falcon 9 rocket. NASA teams will review, verify, and evaluate both those individual systems and components as well as the overall SpaceX launch system. NASA teams will continue to conduct independent analysis and testing to ensure all identified risks have been mitigated or accepted.
“To make this decision, our teams conducted an extensive review of the SpaceX ground operations, launch vehicle design, escape systems and operational history,” said Kathy Lueders, manager of NASA’s Commercial Crew Program. “Safety for our personnel was the driver for this analysis, and the team’s assessment was that this plan presents the least risk.”
Additional verification and demonstration activities, which include five crew loading demonstrations of the Falcon 9 Block 5, will be critical to final certification of this plan. These loading demonstrations will verify the flight crew configuration and crew loading timeline prior to Demo-2. After these conditions have been met, NASA will assess any remaining risk before determining that the system is certified to fly with crew.
If all goes according to plan, on launch day, the Falcon 9 composite overwrap pressure vessels, known as COPVs, will be loaded with helium and verified to be in a stable configuration prior to astronaut arrival at the launch pad. The astronauts then will board the spacecraft about two hours before launch, when the launch system is in a quiescent state. After the ground crews depart the launch pad, the launch escape systems will be activated approximately 38 minutes before liftoff, just before fueling begins. SpaceX launch controllers then will begin loading rocket grade kerosene and densified liquid oxygen approximately 35 minutes before launch. The countdown and launch preparations can be stopped automatically up to the last moment before launch. In the unlikely event of an emergency at any point up to and after launch, the launch escape systems will allow the astronauts to evacuate safely.
This timeline is consistent with the fueling procedures SpaceX uses for its commercial resupply missions and satellite launches.
The crew launches of NASA’s Commercial Crew partners SpaceX and Boeing will return the nation’s ability to launch our astronauts from the United States to and from the International Space Station on American spacecraft.
Source : Scitechdaily
