Image: NASA/Cory Huston
NASA early Saturday called off its second attempt to launch the Artemis 1 mission into lunar orbit after engineers were unable to seal a hydrogen leak that occurred while loading propellants into the rover’s fuel tanks. center stage of the rocket. After the second launch attempt failed, NASA will likely not fire for a third attempt in September.
NASA said the hydrogen leak occurred at an “interface between the liquid hydrogen fuel supply line and the Space Launch System (SLS) rocket.” The SLS is capable of carrying the Orion spacecraft, astronauts and supplies to the Moon in a single mission.
The second launch of the Artemis 1 mission, an unmanned test, was set for Saturday at 2:17 p.m. ET (11:17 a.m. PT) at the Kennedy Space Center in Florida.
The SLS center stage, manufactured by Boeing, is 212 feet (64.6 meters) tall with a diameter of 27.6 feet (8.4 meters). It stores cryogenic liquid hydrogen and liquid oxygen, as well as the systems to power the stage’s four R2-25 engines.
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Artemis is a multi-stage project that plans to send astronauts back to the Moon and beyond. The Artemis mission will also see the first woman and person of color land on the Moon.
NASA’s Artemis mission team had previously canceled an Aug. 29 launch attempt when engineers were unable to cool the four RS-25 engines to minus 420 degrees Fahrenheit (-250 C), a necessary step to ensure that the center stage was not damaged at eight. -One-minute trip to low Earth orbit. After reaching low Earth orbit, the center stage separates from the upper stage and the Orion spacecraft.
During the second launch attempt, one of the four engines showed higher temperatures than the others, according to NASA. This so-called “bleed test” happens before the super-cold liquid hydrogen flows into the rocket’s center stage.
During the first launch attempt, engineers also discovered a hydrogen leak in a “purge can”, but at this stage it could be managed by manually adjusting propellant flow rates.
After Saturday’s failed bid to launch the Artemis 1 mission, NASA revealed it tried three times to cover up the leak.
“Engineers saw a leak in a cavity between the side of the floor and the side plates of the rocket surrounding an 8-inch line used to fill and drain liquid hydrogen from the SLS rocket. Three attempts to reposition the seal was unsuccessful,” NASA said in an update on Saturday evening.
NASA is investigating whether an “inadvertent command” sent during an initial phase of hydrogen loading temporarily increased the pressure in the system and may have contributed to the seal leak.
“While in an early phase of hydrogen loading operations called chilldown, when launch controllers cool the lines and propulsion system before flowing super-cold liquid hydrogen into the rocket tank at minus 423 degrees F, sent an inadvertent command that temporarily increased pressure. Although the rocket remained safe and it’s too early to tell if the pressurization stroke contributed to the leaky seal, engineers are looking into the problem.” say NASA.
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At approximately 11:17 a.m. ET, about three hours before Saturday’s launch window opened, Artemis launch manager Charlie Blackwell-Thompson opted to scrub the second attempt.
According to Reuters, NASA had booked backup launch times for Monday or Tuesday this week, but concluded that it would take longer to repair the new hydrogen leak. The next available window is between September 19 and 30 or another window in October, NASA Associate Administrator Jim Free said at a media briefing.
Mike Sarafin, NASA’s Artemis mission manager, said it would take “several weeks of work” to resolve the current technical issues. If that involves returning the SLS to the assembly building, any launch could be pushed back to mid-October.
According to NASA’s Artemis mission availability webpage, there are 11 launch opportunities between October 17 and October 31. The rocket cannot be launched on any day: there are four key criteria to be met.
- The day of the launch must take into account the position of the Moon in its lunar cycle so that the upper stage of the SLS rocket can time the translunar injection burn to intercept the “on-ramp” of the distant lunar retrograde orbit .
- The resulting trajectory must ensure that Orion is not in darkness for more than 90 minutes at a time, so that the solar array wings can receive and convert sunlight into electricity.
- It must support a trajectory that allows for the planned “jump entry” technique during Orion’s return to Earth, which sees the spacecraft plunge into the Earth’s upper atmosphere, slow down and return to exit the atmosphere, and then re-enter by final descent and splash.
- The launch date should mean a splash of daylight for Orion to facilitate the recovery of the spacecraft from the Pacific Ocean.