NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard is seen atop the mobile launcher at Launch Pad 39B on Monday, August 29, 2022, as the Artemis I launch teams load more than 700,000 gallons of cryogenic propellants including liquid hydrogen and liquid oxygen as the launch countdown progresses at NASA’s Kennedy Space Center in Florida. Credit: NASA/Joel Kowsky
NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is "To discover and expand knowledge for the benefit of humanity." Its core values are "safety, integrity, teamwork, excellence, and inclusion."” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NASA remains on schedule for an Artemis I cryogenic demonstration test on Wednesday, September 21. In the days since the previous launch attempt, engineering teams have analyzed the seals that were replaced on an interface for the liquid hydrogen fuel line between the Space Launch System (SLSNASA's Space Launch System (SLS) will be the most powerful rocket they've ever built. As part of NASA's deep space exploration plans, it will launch astronauts on missions to an asteroid and eventually to Mars. As the SLS evolves, the launch vehicle will to be upgraded with more powerful versions. Eventually, the SLS will have the lift capability of 130 metric tons, opening new possibilities for missions to places like Saturn and Jupiter.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>SLS) rocket and the mobile launcher. They also adjusted procedures for loading cryogenic, or supercold, propellants into the rocket. A small indentation was discovered by engineers on the eight-inch-diameter liquid hydrogen seal. It may have been a contributing factor to the leak on the previous launch attempt.
With new seals, updated cryogenic procedures, and additional ground software automation, Artemis teams are now preparing to demonstrate the updates under the same cryogenic conditions the rocket will experience on launch day. The four main objectives during the demonstration include assessing the repair to address the hydrogen leak, loading propellants into the rocket’s tanks using the new procedures, conducting the kick-start bleed, and performing a pre-pressurization test.
Credit: NASA/MSFC
Based on recent engineering assessments, the new cryogenic loading procedures and ground automation will transition temperatures and pressures more slowly during tanking. This is expected to reduce the likelihood of leaks that could be caused by rapid changes in temperature or pressure. After the liquid hydrogen tank transitions from the slow fill phase to fast fill, NASA teams will initiate, or “kick-start,” the flow of liquid hydrogen through the engines to begin conditioning, or chilling them down, for launch.
After both tanks have reached the replenish phase, the pre-pressurization test will bring the liquid hydrogen tank up to the pressure level it will experience just before launch while engineers calibrate the settings for conditioning the engines at a higher flow rate, as will be done during the terminal count. Performing the pressurization test during the demonstration will enable teams to dial in the necessary settings and validate timelines before launch day, reducing schedule risk during the launch countdown.
The four RS-25 engines on NASA’s Space Launch System rocket produce more than 2 million pounds of thrust. The four RS-25 engines last fired during the core stage Green Run hot fire test at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, in March 2021. Credit: NASA/Robert Markowitz
Call to stations for the demonstration occurred at 5 p.m. EDT (2 p.m. PDT) Monday, September 19. The launch director is expected to give a “go” to begin loading cryogenic propellants into the rocket at approximately 7 a.m. on Wednesday. The test is planned to conclude around 3 p.m. after the teams have met the objectives and will not go into the terminal count phase of the launch countdown. Teams may extend the duration of the test should circumstances warrant it.
During the test, teams will load propellants into both the core stage and upper stage tanks, and Orion and the SLS boosters will remain unpowered. Meteorologists currently predict favorable weather for the test with a 15% chance of lightning within 5 nautical miles of the area, which meets the criteria required for the test. Meteorologists will continue to monitor expected conditions.
NASA Television will provide live coverage with commentary of the demonstration beginning at 7:15 a.m. EDT (4:15 a.m. PDT) on Wednesday, September 21. Continuous live video of the Artemis I rocket and spacecraft at Launch Pad 39B remains available on the Kennedy Newsroom YouTube Channel.
Source: SciTechDaily
