NASA’s hopes fade for SLS test flight this year – Spaceflight Now

The first lunar rocket in NASA’s space launch system could be deployed from the vehicle assembly building to its oceanfront launch complex in Florida, officials told Spaceflight Now, leaving little time for a test refueling, bring the rocket back to the VAB for the final fences, then return to the pad for takeoff before the end of the year.

Stacking and testing the SLS heavy rocket took longer than NASA’s best projections earlier this year. But it’s not unexpected for the first time that teams have assembled the powerful new launcher inside the VAB at NASA’s Kennedy Space Center.

“It went well, in my opinion, for the first few operations,” said Cliff Lanham, senior director of vehicle operations for NASA’s exploration ground systems program, in a recent interview with Spaceflight Now. . “Everything is new for us, but in general things have gone well. “

Lanham said NASA, backed by ground systems contractor Jacobs, intentionally delayed stacking some elements of the space launch system this summer to complete some “higher priority” work in the critical path of the first. unmanned SLS test flight, which NASA calls Artemis 1.

Priority tasks included an initial power-up of the SLS mid-stage avionics and loading the flight software into the rocket’s computer system. The work also involved checks of an environmental control system before powering up the rocket.

NASA engineers didn’t find any major issues during SLS testing, but the key milestones leading up to the launch of Artemis 1 have gradually slipped to the right on NASA’s processing schedule.

Before NASA moved the Boeing-made SLS center stage to its mobile launch pad inside VAB’s High Bay 3 in June, officials hoped to connect the Orion spacecraft for the Artemis 1 mission at the top. of the rocket in August. It is now scheduled for this fall.

The first deployment of the VAB’s 322-foot-high (98-meter) rocket to Launch Pad 39B was scheduled for September at the earliest. This is now expected in late November, at the earliest, according to Lanham.

The schedule shifts, while not significant amid the history of SLS program delays, have put a major damper on NASA’s ambition to launch the Artemis 1 mission this year. The agency is evaluating opportunities to launch Artemis 1 in the second half of December, multiple sources said, but this would require NASA to halve the time initially allotted between the SLS refueling test and the actual launch date.

Earlier this month, NASA stacked an Orion Stage Adapter test article on the SLS in High Bay. The flight adapter will link the Orion spacecraft to the SLS upper stage and also carry a dozen CubeSats into deep space as ride-sharing payloads.

Next, the ground crews lifted a cylinder called the Mass Simulator for Orion above the rocket. This structure mimics the weight of the Orion spacecraft built by Lockheed Martin, allowing technicians to perform resonance measurements across the entire rocket stack, an important step NASA calls modal testing.

With the stacked mass simulator, ground crews began a series of interface verification tests earlier this year. These will be followed by an umbilical release and retraction test, during which engineers will check the swingarm delivery fluid release system and the support connections between the mobile launch tower and the SLS rocket.

The swing arms will rotate or move away from the rocket on takeoff.

Then the teams will move on to modal testing. The stingers, or shakers, will introduce vibrations to the rocket as it stands on its support poles at the base of the movable launch pad. Sensors across the rocket and along the mobile launch tower will measure the resonance response to vibrations.

The solid fuel boosters mounted on the sides of the rocket each rest on four vehicle support poles, the weight of the vehicle holding it on the moving platform – without the aid of hold-down bolts – during stacking, the deployment and countdown to take off.

Lanham said NASA’s ground systems team hopes to complete modal testing in September.

So we’d go into, you know, around the end of August-beginning of September, we’d go into the T-URL followed by modal, and we’d ideally end up in mid-September with the modal tests.

This will be followed by the removal of the Orion Mass Simulator and the Orion Stage Adapter test item. These will be replaced by the flight-ready stage adapter and the real Orion spacecraft, which has been supplied with a maneuver thruster in space and mated to its launch interrupt system at Kennedy.

Technicians are completing the installation of the bullet fairings above the Orion spacecraft, providing the aerodynamic shield that will cover the capsule during launch.

After further testing to verify the mechanical and electrical connections between the Orion spacecraft and the SLS rocket, NASA will be ready to roll the fully assembled launcher to place the 39B on one of the Apollo-era tracked carriers from the agency.

The rocket will spend about a week on the platform before the NASA launch team performs a simulated countdown, culminating in the loading of liquid hydrogen and super-hold liquid oxygen aboard the launch vehicle.

Assuming this test, known as the wet dress rehearsal, is successful, teams will drain the thruster, secure the rocket, and return the space launch system to the vehicle assembly building for final fencing.

Urgent work inside the VAB after the wet dress rehearsal will include the installation of pyrotechnic ammunition for the rocket separation systems and the scope safety destruction mechanism, which would end the flight if the rocket deviated. of its trajectory after take-off.

Then the rocket will return to pad 39B for another week of preparations before the first launch attempt.

During launch, the main stage Rocketdyne RS-25 Aerojet engines and twin powder rocket thrusters will generate 8.8 million pounds of thrust. It can send about 59,500 pounds (27 metric tons) of payload to the moon, according to NASA.

The Artemis 1 mission will propel the Orion spacecraft on a mission to orbit the Moon for several weeks, before the capsule returns to Earth for a landing in the Pacific Ocean. Artemis 1 will pave the way for the next SLS / Orion mission, Artemis 2, to transport a crew of four around the moon in 2023.

Artemis missions later in the 2020s will land astronauts near the moon’s south pole using commercially developed lunar landers. In April, NASA selected a variant of SpaceX’s spacecraft, a reusable heavy-lift rocket under development with majority private funding, to land Artemis’ first crew on the moon.

But NASA plans to use the government-owned space launch system rocket and Orion capsule for the round-trip flight between Earth and the vicinity of the moon, where astronauts will be transferred to a lunar lander, such as the spaceship, to descend to the surface.

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Follow Stephen Clark on Twitter: @ StephenClark1.