NASA unveils its colossal moon rocket in grand display

NASA paraded its megarocket to the launchpad in Cape Canaveral, Florida, on Thursday evening, and not just for a flashy photo-op a la the Oscars red carpet.

The U.S. space agency is readying the 5.75 million-pound behemoth for a mission to the moon, known as Artemis I. It's the first in a series of deep space exploration voyages that could lift off as early as May. The upcoming launch won't include astronauts, but the flight will prepare NASA to send a crew on the next, more complex mission, Artemis II.

At its Kennedy Space Center launchpad, the fully assembled rocket, known as the Space Launch System, with the Orion spacecraft on top, will undergo a so-called "wet dress rehearsal" because the crucial test involves filling the rocket with liquid fuel. Only after successfully completing this loading and countdown simulation will NASA set a date for the first lunar mission, agency leaders say.

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The redeye rollout of the 322-foot rocket began at 5 p.m. ET and continued through nightfall. It arrived at the launch site at about 4 a.m. ET Friday. Eventually, the wet dress rehearsal will begin on April 3 and occur over two days.

Wheeling out the rocket was a grander display than the last time NASA showcased its largest rocket. When the agency hauled the (now retired) Space Shuttle to the launch pad, the team transported it under the cover of darkness at midnight, Mike Bolger, exploration ground systems program manager, said during a call with reporters in February.

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NASA's moon rocket begins the 4-mile trek to the launchpad for a wet dress rehearsal. Credit: NASA / Joel Kowsky

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Since then, the agency has perhaps learned a lesson in public relations, taking advantage of a spectacular Space Coast sunset for the road trip, which will creep at speeds less than 1 mph.

"This is a very different vehicle than what we normally see here in Florida," said Tom Whitmeyer, associate administrator for exploration systems development, in a press briefing on Monday. "There hasn't been something like this for quite some time."

What makes this rocket stand out (pun intended) is its imposing, colossal height. The megarocket towers above the Statue of Liberty and London's Big Ben, comparable in size to Saturn V, the rocket used for the Apollo missions.

"It just catches your breath," Whitmeyer said.

The journey from storage to launchpad is about four miles — some might say the longest four miles of NASA engineers' lives. It will take around 11 hours for the megarocket to lumber down the path on a crawler transporter, a more than 50-year-old machine reminiscent of a Star Wars mobile desert fortress.

Once the rocket is docked at the launch pad, the team will connect the mobile launcher to utilities, such as water for fire suppression, power, and air. The next step is a meeting to assess the health and status of the rocket and Orion spacecraft. Lastly, the team will load the core and upper stages of the rocket with propellant, liquid hydrogen, and liquid oxygen.

The wet dress rehearsal allows the team to practice fueling and walking through a countdown. If you get fidgety at the gas station, consider this: Filling the tanks of the megarocket will take about eight hours. By comparison, the Space Shuttle only took 2.5 hours.

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NASA engineers will also practice a "scrub." A so-called "scrub" is aeronautics-speak for a cancellation. In theory, the space agency can call off a launch right down to the wire for foul weather, temperature, mechanical failures, or a litany of other problems. Back in the Space Shuttle days, a launch was once delayed because a woodpecker poked over 200 holes in an external fuel tank.

After filling'er up, the NASA team will practice a launch countdown, stopping with just 10 seconds remaining. Then, they'll rehearse resetting the countdown clock to 10 minutes before takeoff. The tests will conclude with draining the fuel from the rocket.

"The next time when we roll, when we actually roll out for launch, we'll refer to that four-mile trip as the first four miles of NASA's return to the moon," Bolger said.

UPDATE: Mar. 18, 2022, 10:30 a.m. EDT NASA's Space Launch System rocket successfully arrived at Launch Complex 39B at the Kennedy Space Center.