NASA will press ahead with preparations for a second launch attempt of its new lunar rocket on Saturday, NASA officials said during a press conference on Tuesday.
Mission managers have come up with a plan they hope will resolve a rocket engine problem encountered during Monday’s first launch attempt.
The SLS rocket is the modern equivalent of the Saturn V rocket that took NASA astronauts to the Moon during the Apollo program half a century ago, and is a cornerstone of NASA’s Artemis program, which aims to return astronauts to the Moon in the coming years.
There won’t be any people on board for this mission, Artemis I, but it is a critical test of the rocket and Orion capsule for the crew, which the astronauts will ride during later missions. During the weeks-long journey, Orion will go into orbit around the Moon and then return to Earth.
The launch is now scheduled for a two-hour launch window on Saturday, beginning at 2:17 p.m. ET, although inclement weather could pass over the launch pad at the Kennedy Space Center in Florida at that time.
The problem that halted the launch on Monday was a liquid hydrogen streak that did not adequately cool one of the rocket’s four primary stage engines, part of the preparations needed before ignition.
John Honeycutt, the program manager supervising development of the Space Launch System rocket, said three of the engines had temperatures close to the minus 420 degrees Fahrenheit target, while the other was about 40 degrees warmer. Without cooler, a supercooled fuel temperature shock can break metallic engine parts.
However, Mr Honeycutt said, the warmer reading was probably the result of a faulty sensor. He said the engineers were analyzing other data that could verify that all the engines were cool enough.
“The way the sensor behaves doesn’t match the physics of the situation,” said Mr. Honeycutt. “And so we’ll look at all the other data we have, to use it to make an informed decision whether or not we have the engine, all engines have been cooled or not.”
It could mean that the countdown will continue on Saturday, even if the same temperature readings occur.
“What we need to do is keep looking at the data and then improve our plan on putting together the rationale for the trip,” said Mr. Honeycutt. “I think we have enough data to do that, but we will have to let the data guide us.”
Additionally, for the next launch attempt, a cooling test will be conducted 30 minutes to 45 minutes beforehand to reproduce what was accomplished during a successful launch test of core stage engines last year at the Stennis Space Center in Mississippi.
This week, technicians will also look at the leak that occurred while filling the rocket’s fuel tanks on Monday and tightening connections in the fuel line attached to the bottom of the rocket. This work can be done on the launch pad without the missile returning to the Vehicle Assembly Building, an enormous facility used to assemble and maintain missiles.
During Monday’s launch attempt, engineers were able to stop the leak and resume the flow of hydrogen into the tank.
Mission managers will also meet on Thursday to decide whether to go ahead with the launch attempt on Saturday.
If NASA cannot launch by early next week, it will have to return the rocket to the Vehicle Assembly Building. The flight termination system – explosives that can destroy the missile if it derails – must be retested 25 days after it is installed, and this can only be done in the vehicle assembly building.
Even when engineers try to fix technical issues, other variables are out of NASA’s control.
Weather conditions on Saturday “favor showers and perhaps a few thunderstorms moving from the coast during the morning and early afternoon hours,” Mark Burger, launch meteorologist for the US Space Force’s 45th Weather Squadron, said.
Mr Burger estimated the probability of a weather violation during the launch window being “close to 60 percent”, but added that there might be pockets of clear sky in between.
“We have a couple of hours to work with them,” he said, “and these bathrooms often have a great deal of real estate in between.” “So I still think we have a very good chance in terms of the weather to launch on Saturday.”
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