Having rolled the Space Launch System lunar rocket out to its launch pad and powered it up successfully, NASA engineers and technicians say they’re just about ready for a prelaunch wet dress rehearsal this week.
During the prelaunch test, which is scheduled to kick-off on April 1, the rocket and team will run through launch day procedures from fueling to just before start up, without actually launching the behemoth.
“NASA’s mega moon rocket is sitting at the pad, it’s powered up and ready for final testing,” Tom Whitmeyer, deputy associate administrator for common exploration systems development, NASA Headquarters in Washington, D.C., said during a media teleconference Tuesday.
The news sets the stage for the massive SLS to blast off an a jaunt around the moon in the next few months. Before it can do that, the rocket needs to carry out its last major milestone, a wet dress rehearsal.
“Wet dress is a two-day test designed to closely follow the launch day countdown,” said Charlie Blackwell-Thompson, Artemis launch director, NASA Exploration Ground Systems program, NASA Kennedy.
Blackwell-Thompson said the teams will put a variety of systems through their paces, including the command and control system in the launch control center, as well as ground systems at the launch pad.
Engineers will also load, and unload, the vehicle with the 700,000 gallons of super-cooled liquid hydrogen and liquid oxygen the vehicle’s engines and core stage rely on.
“Tanking — fuel loading — is a very interesting process,” Whitmeyer said. “The fuel is very cold, so it’s like watching a ballet — you’ve got pressure, volume and temperature all working in sync as the fuel is loading.”
The planned wet dress follows the slow trek from NASA’s massive Vehicle Assembly Building to the launch pad, a journey that took the mega launcher about 11 hours.
“[The rollout] was an iconic moment — a very special moment for us here at NASA,” Whitmayer said. “We had more than 7,000 people in attendance at the roll out — these folks are the ones who have worked so hard on this rocket.”
First conceived in 2011, NASA has spent more than a decade on the development of SLS. The eventual goal is for the vehicle to carry astronauts and cargo out into deep space, the moon and Mars.
Each SLS rocket uses four RS-25 engines to launch its 212-foot-tall core stage. It also relies on two solid rocket boosters strapped to the core’s sides and an upper stage to propel NASA’s Orion crew capsule beyond low Earth orbit.
SLS will embark on a series of lunar missions, culminating in boots on the lunar surface for the first time since 1972.
The first mission, called Artemis 1, will send the SLS rocket currently perched atop Pad 39B at NASA’s Kennedy Space Center on an uncrewed trip around the moon. It will be the first-ever flight for the SLS and the second for its crew capsule, called Orion, which took an uncrewed trip around the Earth in 2014.
Lasting roughly a month, Artemis 1 is to be followed by Artemis 2 in 2024, sending astronauts around the moon. Artemis 3 is expected to land people on the moon as soon as 2025 or 2026.
Once the prelaunch testing is complete, the rocket will be rolled back to NASA’s Vehicle Assembly Building, where the SLS was pieced together.
After a thorough review of the data, NASA plans to announce an official start date for the Artemis 1 mission, which is currently expected no earlier than June. The agency said will set a firmer launch date once testing is complete and engineers know how the vehicle performed.
The agency last month said the launch would slip to April or May, noting at the time that there were no “major issues” but that there were things to close out ahead of the uncrewed test flight of the new rocket.
