Saturday Night Space Agency Announce plans to roll off the large SLS rocket from the launch pad at the Kennedy Space Center to the Vehicle Assembly Building in the coming days. This represents a significant step back for the program, which since April 1 has attempted to load the rocket with supercooled liquid hydrogen and liquid oxygen (a “wet” rehearsal test), check important models and software interface.
The decision comes after three attempts over the past two weeks. Each attempt to refuel was thwarted by one or more technical problems with the missile, mobile launch tower, or ground systems providing the fuel and gases. During the last attempt, Thursday, April 14, NASA successfully loaded 49 percent of the primary stage liquid oxygen fuel tank and 5 percent of the liquid hydrogen tank.
While this is an advance, it did not include the more dynamic part of the test, during which the rocket is fully refueled and pressurized; Ground and computer systems are put into the final countdown when each variable is closely monitored. NASA had hoped to complete this rehearsal test to work out the kinks of the complex launch system so that when the rocket launches later this year for its actual launch, the countdown will continue fairly smoothly.
NASA said its contractors, as well as its agency, will use the next several weeks to address problems that arose during refueling tests when the SLS rocket returns to the large vehicle assembly building. For example, Air Liquide, a supplier of gaseous nitrogen system, will upgrade its capabilities. NASA will also replace a defective check valve on the rocket’s upper stage, as well as fix a leak in the mobile launch tower’s “secret tail service mast,” the 10-meter-high structure that provides the missile’s thruster and electrical lines to the pad.