After months of testing, troubleshooting and repairs, engineers fitted the Moon’s Space Launch System rocket for Monday’s long-awaited explosion on NASA.A mission to send an unmanned Orion crew capsule on a 42-day mission beyond the moon and back. But after working through weather delays and a brief indication of a hydrogen leak, a cooling problem for one of the rocket’s main engines forced managers to cancel the countdown.
“We don’t shoot unless it’s true,” said NASA Administrator Bill Nelson. “I think it’s clear that this is a very complex machine, a very complex system, and all of these things have to work. You don’t want to light the candle until it’s ready to go.”
It was a frustrating disappointment to the more than 25,000 NASA employees, dignitaries, and other guests who gathered at the Kennedy Space Center to witness the historic launch, and to the thousands of area residents and tourists lining the area’s roads and beaches.
It was equally frustrating for the hundreds of engineers and technicians who worked for months to prepare the giant moon rocket for launch. But it wasn’t to be.
“This is just part of the space business, and it’s part of a test flight in particular,” Nelson said. “We’re toughening and testing this rocket and spacecraft in ways you’d never do with a crew on board. That’s the purpose of a test flight.”
However, NASA did not risk the $4.1 billion rocket, the most powerful rocket ever built for the civilian space agency and a key factor in its plans to return astronauts to the Moon in the next three years in the Artemis program.
After repeated attempts to solve the hydrogen cooling problem failed, launch manager Charlie Blackwell-Thompson canceled the countdown at 8:35 a.m. EDT, two minutes after the two-hour launch window opened at 8:33 a.m.
next oneAssuming the issues you encountered on Monday can be resolved in time and assuming no additional fuel testing is needed, it’s 12:48 PM on Friday.
Depending on the ever-changing positions of the Earth and Moon, there’s only one more chance after that — September 5 at 5:12 p.m. — before the rocket is pulled off the platform and back to the iconic Vehicle Assembly Building for servicing.
In this case, the launch will likely begin in late September or, more likely, October. But no decisions will be made until the engineers have had time to review the data and determine what needs to be fixed or modified.
The launch team will “get to the end of it, they’ll fix it and then we’ll fly,” Nelson said.
The Artemis 1 test flight aims to verify the rocket’s ability to propel Orion capsules into Earth orbit and then onto the Moon. Engineers will also test the ship’s myriad crew systems in deep space and ensure that the heat shield can protect the returning astronauts from the 5,000-degree return heat.
NASA plans to follow up on the unmanned Artemis 1 mission by launching four astronauts on a circular flight around the Moon in 2024, paving the way for the first astronaut to land in nearly 50 years when the first woman and next man step onto the surface in the 2025-26 time frame .
But first, NASA must demonstrate that the rocket and capsule will operate as planned, beginning with an uncrewed Artemis 1 test flight.
SLS missile isBuilt by NASA, it stands 322 feet tall, weighs 5.7 million pounds when loaded with fuel and generates 8.8 million pounds of thrust on takeoff, 15 percent more than NASA’s legendary Saturn 5, the current record holder.
The countdown began on Saturday and continued smoothly until late Sunday night when marine storms with rain and lightning moved within about six miles of Launch Complex 39B, violating NASA safety rules.
After a 55-minute delay, the six-hour refueling finally began at 1:14 a.m., as engineers, working by remote control, began pumping 730,000 gallons of supercooled liquid oxygen and hydrogen fuel into the primary stage of the SLS, Paving the way for another 22,000 gallons to be pumped into the upper stage.
During the transition from “slow fill” to a 10 times faster rate, sensors detected higher than permissible concentrations of hydrogen in the umbilical housing delivering propellant to the base of the primary stage, indicating a leak somewhere in the system.
After returning to a slow fill and allowing the temperatures to balance through the plumbing, a quick refill was done and this time, there were no issues.
Then another issue developed. When the hydrogen tank was full, propellant was diverted to the four RS-25 engines at the base stage to cool or condition them, to the extremely low temperatures they would encounter at the high flow rates needed for ignition.
NASA reported that three of the engines were properly adapted, but engine number 3 did not initially “see” the required flow. This led to further troubleshooting, including increasing the pressure in the line, to no avail.
NASA did four countdowns to dress rehearsals and fueling tests that led to Monday’s attempt, and all four ran into problems. During the most recent test on June 20, a leak occurred in one of the 4-inch quick-disconnect fixtures, used to direct hydrogen into engines for cooling.
The installation was fixed back in the Vehicle Assembly Building, but the work was done under ambient conditions. Hydrogen leaks usually only appear in extremely cold conditions, which didn’t happen until Monday.
There were no indications of any additional leaks this time around, and it wasn’t immediately clear what was causing the cooling problem on engine #3.
As if that wasn’t enough, an unusual streak of frost was observed on the outside of the rocket’s core stage, a possible indication of a leak of some sort. But as it turned out, the frost was caused by a slight stress crack in the tank insulation and was not a problem with the launch.
But the hydrogen issues couldn’t be resolved before the end of the launch window, and Blackwell-Thompson canceled the countdown.
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