'Hubble Hugger' space shuttle engine mounted on Artemis 2 moon rocket (photos)

view of hubble with two solar panels above a space shuttle in space. the earth is behind. a robotic arm is between the shuttle and hubble
Space shuttle Atlantis (bottom) releases the Hubble Space Telescope into a free-flying orbit on May 19, 2009, using the robotic Canadarm. An RS-25 engine powering that space shuttle is now being used for Artemis 2, a human moon mission. (Image credit: NASA)

A rocket engine that helped power a servicing mission to the Hubble Space Telescope is now readying for the moon.

NASA's Artemis 2 mission is scheduled to fly four astronauts around the moon no earlier than November 2024. The big Space Launch System (SLS) rocket that will launch Artemis 2 is coming together: Technicians at a NASA center installed the first of four recycled R-25 space shuttle engines on the powerful rocket's core stage on Monday (Sept. 11). 

That engine, No. E2059, was once nicknamed a "Hubble Hugger" by NASA officials due to a special mission it had with the space shuttle: Making the last astronaut visit to the Hubble Space Telescope to service the venerable observatory, on the STS-125 mission in 2009. Hubble continues to run in excellent health today, 14 years later.

Artemis 2 will send NASA's Reid Wiseman, Victor Glover and Christina Koch, along with Canadian Space Agency astronaut Jeremy Hansen, around the moon and back. Glover, Koch and Hansen will become the first Black person, the first woman and the first non-American, respectively, to travel beyond low Earth orbit. The four astronauts are already deep in training for the effort.

Related: How Artemis 2 astronauts are training for their 2024 moon mission

Engine E2059 on the Boeing-made SLS core stage flew to space five times during the space shuttle program, according to NASA. Notably, it delivered the wraparound cupola viewing window to the International Space Station aboard mission STS-130 in 2010.

Two of the remaining three RS-25 engines (E2062 and E2063) to be installed on the SLS core stage are new engines with flown hardware inside, while the third (E2047) flew on 15 space shuttle missions.

When the four RS-25 engines, manufactured by Aerojet Rocketdyne, roar to life on SLS, they will burn their fuel at a rate that would drain one Olympic-sized swimming pool each second: that's 1,500 gallons (5,678 liters), according to agency documentation.

The core stage is being assembled at NASA's Michoud Assembly Facility in New Orleans. After assembly, it will be shipped to its launch site at NASA's Kennedy Space Center (KSC) in coastal Florida by barge. There, the core stage will be mated to the rest of the rocket and then tested ahead of the historic launch.

While the rocket is being put together, ground teams are working on other prelaunch prep. The high tower supporting the rocket is now at Launch Pad 39B at KSC undergoing months of testing, with new steps being added to assure crew safety, as this is the first launch with astronauts of NASA's Artemis program.

And on Monday — the same day the first rocket engine was being mounted to the Artemis 2 SLS core stage — a team led by NASA launch director Charlie Blackwell-Thompson completed a terminal countdown at KSC to get ready for key liftoff milestones, NASA officials wrote on X (formerly Twitter).

Artemis 2 is the second mission of NASA's larger Artemis program, which includes international funding and hardware. The first one, Artemis 1, saw the SLS send the Orion spacecraft on an uncrewed mission to lunar orbit and back late last year. Assuming that Artemis 2 goes to plan, NASA will send another quartet of astronauts to the moon again in late 2025 or 2026.

The primary goal of that mission, called Artemis 3, is to land some of those people on the moon, in the first such effort since Apollo 17 in 1972. NASA, however, is awaiting the arrival of key hardware such as the SpaceX Starship lander that will carry astronauts to the surface, and the spacesuits that will be used for lunar excursions.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for Space.com for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: https://qoto.org/@howellspace

  • MetalMan
    This article states that "the four RS-25 engines . . . . will burn their fuel at a rate that would drain one Olympic-sized swimming pool each second: that's 1,500 gallons." I have a 1500-gallon anhydrous ammonia tank not far from my house, and although it's a pretty good-sized tank, it is far, far smaller than the volume of water in an Olympic-sized swimming pool. I'd estimate that this statement is off by about a factor of 100.