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NASA returns the SLS moon rocket to the hangar tonight – Spaceflight Now

NASA’s powerful new Space Launch System moon rocket will be transported from its launch pad to the Kennedy Space Center’s Vehicle Assembly Building overnight Friday through Saturday morning for final repairs, testing and shutdowns, closing in on liftoff later this summer after completing a fueling demonstration last month.

The 322-foot-tall (98-meter) lunar rocket is expected to leave its posts at pad 39B beginning around 11 p.m. EDT Friday (0300 GMT) Saturday. A diesel-powered crawler transporter will carry the Space Launch System rocket up the ramp and along the rock-covered crawler path on the 4.2-mile (6.8-kilometer) journey to the assembly building of vehicles, a trip that should take 8 to 12 hours.

The return of the SLS lunar rocket to the Vehicle Assembly Building brings the Artemis 1 mission one step closer to launching a test flight around the moon. After a decade of development costing more than $20 billion, the Artemis 1 mission will mark the first flight of the massive SLS lunar rocket, sending an Orion crew capsule on a trajectory in orbit around the moon.

The test flight will not carry astronauts, but will be the first launch of a rocket and spacecraft to the Moon since the Apollo program. If the Artemis 1 flight goes as planned, NASA intends for the next SLS/Orion mission – Artemis 2 – to carry a crew of approximately on a loop around the far side of the moon and back to Earth in 2024, marking the first astronaut to travel to the moon since 1972.

Future Artemis missions will include a commercial crew lander to transport astronauts between the Orion spacecraft in lunar orbit and the surface of the moon.

The NASA launch team fully loaded the moon rocket with cryogenic liquid hydrogen and liquid oxygen propellants during a practice countdown on June 20, accomplishing a major test goal that managers wanted to complete before making final preparations for the launch.

A series of practice countdowns in April were plagued by technical issues that prevented full refueling of the rocket.

The repeat of the June 20 countdown was not without its troubles. Engineers have detected a hydrogen leak in a quick-disconnect fitting near the bottom of the rocket’s center stage, in a line that dumps excess hydrogen overboard the system to thermally condition all four engines main RS-25 for ignition.

The launch team overcame the problem and continued the countdown to T-minus 29 seconds, about 20 seconds ahead of the time the engineers wanted to reach in dress rehearsal. One of the end goals of the test not achieved on June 20 was a hot-firing of hydraulic pumps powering the steering mechanisms of the rocket’s two solid-fuel boosters, which provide 80% steering control for the first two minutes. launch.

NASA’s Artemis 1 lunar rocket stands on Pad 39B at Kennedy Space Center on June 30. Credit: Stephen Clark/Spaceflight Now

NASA ground crews successfully activated the hydraulic power units in a separate test on June 25, clearing the way for crews to prepare the rocket for return to the Vehicle Assembly Building.

The return to the rocket hangar was scheduled to begin late Thursday, but NASA pushed the move back a day to complete work on the slope of the track track leading to the launch pad. Crews finished rasping or sifting the track path using heavy equipment before restoring Friday evening.

The robot will reach a top speed of nearly 1 mph during the return trip to the VAB. The combined stack of the SLS moon rocket, its mobile launch platform, and the tracked vehicle weighs approximately 21.4 million pounds.

After working through the night, the NASA ground crew will briefly stop the robot and the SLS moon rocket outside the VAB, allowing time for the crew access arm near the top of the tower. mobile launch of the rocket into position next to the Orion crew capsule on top of the vehicle.

The access arm is retracted against the mobile launcher tower while it is in motion, and cannot be extended once the rocket is inside the assembly building.

With the arm extended, the crawler should move through the vertical door of High Bay 3. The carrier’s lift and leveling system will lower the mobile launch platform onto pedestals inside the VAB to complete the journey from pad 39B.

The space agency hasn’t officially set a target launch date for the first SLS moon rocket, but officials aim to have the launcher ready for liftoff on the Artemis 1 test flight in late August or early September, when the alignment of the moon, the sun and the Earth will allow the mission to achieve all of its objectives.

A introductory period opens on August 23 and ends on September 6. NASA has another launch window available beginning September 19 and extending through October 4, followed by three more two-week launch windows through the end of the year. Depending on when the Artemis 1 mission lifts off, Orion’s test flight could last around 26 days or up to 42 days. The duration of the mission depends on the location of the moon relative to Earth, allowing the Orion spacecraft to perform a half orbit or a distant orbit and a half around the moon.

Launch times are limited by a number of considerations, including the position of the moon in its orbit around Earth, the time limits that the Orion spacecraft can fly in the shadows without direct sunlight on its solar panels, and re-entry and splashdown rules, including the requirement for a daylight return to Earth to aid in recovery operations in the Pacific Ocean.

Launch windows for Aug. 23-Sept. 6 windows are shown below. August 30, August 31, and September 1 are not viable launch dates because not all launch window constraints are met for those days.

Launch windows for Artemis 1 end of August and beginning of September. Credit: NASA / Spaceflight Now

Once the rocket is back inside the assembly building, workers will extend 10 sets of access platforms to reach different levels of the launcher and erect an access support to reach the leaking hydrogen pipe .

In addition to work already planned to prepare the rocket for launch, technicians will repair the leaking hydrogen connector discovered during the refueling demonstration last month. Workers will replace the Teflon seals on the quick-disconnect fittings in the tail service mast umbilical, the connection that carries cryogenic thrusters between the mobile launch pad and the SLS center stage.

Officials believe one of those joints came loose in the 4-inch quick disconnect that began to leak during the June 20 countdown rehearsal. Phil Weber, integration manager for the Artemis ground operations team, said last week that workers will likely replace a similar seal on a larger 8-inch thruster fill and drain line as preventive.

Other work inside the VAB will include changing an avionics box on the SLS upper stage and loading software on the upper stage computer. The ground crew will also stow final equipment inside the Orion spacecraft’s pressurized cabin and install flight batteries on the center stage, boosters and second stage, according to Cliff Lanham, flow manager. NASA Ground Operations Team Artemis 1 at Kennedy.

“Then, ultimately, we want to do our flight termination system testing, and once that’s done, we can do our final inspections on all volumes of the vehicle and do our fences,” Lanham said in a press of June 24. Report.

The flight termination system consists of pyrotechnic charges on the rocket that would be fired to destroy the vehicle if it veered off course and threatened populated areas.

The ground team inside the VAB will arm the flight termination system and conduct an end-to-end test, demonstrating the Space Force Range Security Team’s ability to send a kill command to the SLS lunar rocket. The flight termination system is only certified for 20 days after the end of the test, and the rocket should be taken back to the VAB to revalidate the destruction mechanisms.

According to Lanham, work on the SLS moon rocket inside the Vehicle Assembly Building will take about six to eight weeks.

Weber said the ground crew would “rush” the rocket back to pad 39B after the flight termination system check. The rocket will need to spend 10-14 days on the pad before the first launch attempt, and the timeline currently shows the Artemis 1 team could fit three launch attempts before the system certification clock expires. 20-day flight stoppage.

NASA officials are expected to set a target launch date as early as next week.

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