After months of testing, troubleshooting, and repairs, engineers began powering the Lunar space launch system rocket to lift off Monday on a long-delayed test flight to send an uncrewed Orion capsule on a 42-day journey around the moon.
Lightning showers moved within five nautical miles of Launch Pad 39B just after midnight, forcing launch director Charlie Blackwell-Thompson to delay the start of propellant loading by 55 minutes. But the six-hour procedure finally got underway at 1:13 a.m. EDT.
The only other topic under discussion as the countdown reached its final hours was troubleshooting to find the cause of a momentary communications failure on one of the channels that transmit commands and telemetry to and from the Orion spacecraft.
It was not immediately clear what impact, if any, the delay in fueling and resolving issues might have on the planned 8:33 am launch time. But engineers were optimistic that NASA’s most powerful could lift off on its long-awaited maiden flight sometime during a two-hour launch window.
The carefully designed fueling procedure is required to load 196,000 gallons of liquid oxygen and 537,000 gallons of hydrogen into the massive core stage of the rocket. Another 22,000 gallons of oxygen and hydrogen are required for the upper stage, for a total of 750,000 gallons of propellant.
The SLS’s four shuttle-era engines and two extended-belt solid-fuel boosters will generate a ground-shaking 8.8 million pounds of thrust to propel the 5.7 million-pound rocket away from Pad 39B. at the Kennedy Space Center.
The rocket is part of the Artemis 1 The mission will last just one hour and 36 minutes, propelling the Orion capsule and its European Space Agency-supplied service module into space, out of Earth orbit and on a trajectory toward the moon.
After a close flyby at an altitude of just 60 miles, Orion will quickly return to a distant orbit around the moon for two weeks of testing and verification. If all goes well, the capsule will drop back toward the moon for another close flyby on October 3 that will set up a high-speed descent to a splashdown in the Pacific Ocean on October 10.
NASA plans to follow up the Artemis 1 mission by launching four astronauts in a circular flight around the moon in 2024, setting the stage for the first astronaut landing in nearly 50 years when the first woman and next man step foot on the surface in the time frame. 2025-26.
But first, NASA must prove that the rocket and capsule will work as planned, and that starts with the launch of Artemis 1 on Monday.
Starting about 6.6 seconds before launch, the four RS-25 engines at the base of the core stage will ignite and accelerate to full thrust, generating a combined thrust of two million pounds.
When the countdown reaches zero, after a whirlwind round of computer checks to check engine performance, commands will be sent to ignite both solid rocket boosters. At the same instant, the signals will detonate four explosive bolts at the base of each booster, freeing the SLS from its launch pad.
Solid rocket boosters provide most of the power needed to lift the SLS out of the dense lower atmosphere, firing for two minutes and 10 seconds before falling to an altitude of 27 miles.
The RS-25 core stage engines will continue the ascent on their own, firing for another six minutes to propel the rocket to an altitude of 87 miles.
The core stage’s RS-25 engines will fire for eight minutes, propelling the ship to an altitude of 87 miles before shutting down.
The flight plan called for the rocket’s upper stage, carrying the pilotless Orion capsule and its service module provided by the European Space Agency, to separate from the now-empty core stage and continue to glide skyward to an altitude of approximately 1,100 miles, the highest point, or apogee, of its initial orbit.
The engine driving the interim cryogenic propulsion stage, or ICPS, was expected to ignite 51 minutes after liftoff to raise the low point, or perigee, of the 20-mile orbit to about 115.
Reaching that low point forty-five minutes later, one hour and 36 minutes after launch, ICPS was programmed to fire its RL10B engine for 18 minutes, increasing the vehicle’s speed to approximately 22,600 mph, more than 10 times faster than a rifle. bullet.
That’s what it takes to break free from Earth’s gravity, lifting the apogee to a point in space where the moon will be in five days.
After spreading its four solar wings and separating from ICPS, the Orion capsule will head for a 60-mile-high flyby of the moon on Sept. 3 and then into a “distant retrograde orbit” that will carry the spacecraft farther. from Earth: 280,000 miles. — than any previous human-rated spacecraft.
The flight is the first in a series of missions aimed at establishing a sustained presence on and around the moon with a lunar space station called Gateway and periodic landings near the south pole where ice deposits may be accessible in cold, permanently shadowed craters.
Future astronauts can “mine” that ice if it’s present and accessible, turning it into air, water, and even rocket fuel to greatly reduce the cost of deep space exploration.
More broadly, Artemis astronauts will conduct extensive exploration and research to learn more about the origin and evolution of the moon and to test the hardware and procedures that will be necessary before sending astronauts to Mars.
The objective of the Artemis 1 mission is to put the Orion spacecraft to the test, testing its solar power, propulsion, navigation and life support systems before returning to Earth on October 10 and a 25,000 mph dive into the atmosphere that will subdue to its protective heat shield at a hellish 5,000 degrees.
Testing the heat shield and confirming that it can protect astronauts returning from deep space is the number one priority of the Artemis 1 mission, a goal that requires the SLS rocket to send the capsule to the moon first.
If all goes well with the Artemis 1 mission, NASA plans to launch a second SLS rocket in late 2024 to propel four astronauts on a looping free-return trajectory around the moon before sending off the first woman and next man. to land on the moon’s surface near the south pole on the Artemis 3 mission.
That flight, scheduled to launch in 2025-26, hinges on the readiness of NASA’s new spacesuits for moonwalkers and a lander being built by SpaceX that is based on NASA’s Starship reusable rocket design. company.
SpaceX is working on the lander under a $2.9 billion contract with NASA, but the company has provided few details or updates and there’s no word yet on when NASA and the California rocket builder will actually be ready for the mission. lunar lander Artemis 3. .
But if the test flight of Artemis 1 is successful, NASA may meet its requirement for a super-heavy-lift rocket to launch initial missions. With 8.8 million pounds of liftoff thrust, 15 percent more than the Saturn 5, the SLS rocket is the most powerful ever built by NASA.
Congress directed NASA to build the rocket in the wake of the Space Shuttle retirement in 2011, requiring the agency to use leftover shuttle components and existing technology where possible in an attempt to keep costs down.
But management errors and technical problems caused delays and billions in cost overruns. According to NASA’s Inspector General, the US space agency is “projected to spend $93 billion on Artemis (lunar program) through fiscal year 2025.”
“We also project the current production and operations cost of a single SLS/Orion system at $4.1 billion per launch for Artemis 1 through 4, although ongoing Agency initiatives aimed at increasing affordability seek to reduce that cost.”
Among the causes listed as contributing to the astronomical price of the SLS: the use of single-source cost-incremental contracts” and the fact that, except for the Orion capsule, its subsystems, and supporting launch facilities, all components are expendable and ‘unique'”. use’ as opposed to emerging commercial spaceflight systems.
In stark contrast to SpaceX’s commitment to fully reusable rockets, everything except the Orion crew capsule is thrown away after a single use. As SpaceX founder Musk likes to point out, that’s like flying a 747 jumbo jet from New York to Los Angeles and then ditching the plane.
“That’s a concern,” Paul Martin, NASA’s inspector general, said in an interview with CBS News. “This is a single-use, expendable system, unlike some of the launch systems that exist on the business side of the house, where there are multiple uses. This is a single-use system. And so the $4.1 billion per flight. … we are so concerned that in our reports, we said we see it as unsustainable.”