KENNEDY SPACE CENTER, Fla. — Thousands of people had come from near and far to fill the beaches, roadsides, rooftops, and waterways. Some even camped out overnight hoping to see NASA’s giant new moon rocket launch for the first time, rising with a thunderous roar and fiery jets from its engines.
“We’re leaving,” proclaimed NASA banners hung throughout the space center. Even Vice President Kamala Harris was on hand to watch.
But on Monday, the rocket didn’t leave, and NASA officials said it was too early to guess whether it might launch on Friday, the next potential opportunity, or later. Mission managers will meet Tuesday to discuss their next steps.
Although there will be no astronauts on this test flight, this rocket, which NASA calls the Space Launch System, will usher in a new era of human exploration, including sending the first woman and first person of color to the surface of Moon.
The first mission, without astronauts, will be a week-long flight around the moon to test both the rocket and the Orion crew capsule, where astronauts will sit on future missions. In particular, NASA wants to make sure that Orion’s heat shield can survive a fiery entry through Earth’s atmosphere at 25,000 miles per hour, the speed of a spacecraft returning from the moon.
Monday’s canceled launch added another delay to the lunar program, called Artemis, which has already cost more than $40 billion and is years behind schedule. Nonetheless, the program, including the giant rocket, has received steady support from Congress and NASA officials.
The issue that halted the launch on Monday was a liquid hydrogen line that failed to properly cool one of the rocket’s four core-stage engines, part of the necessary preparations before ignition. Otherwise, the sudden contraction from the temperature shock of the supercold propellants cracks the metal parts of the engine.
Troubleshooting efforts proved unsuccessful within the limited time, and around 8:40 am ET, Charlie Blackwell-Thompson, the release manager, decided it was time to call it off and try again another day. Even if they had worked out the technical issues, weather conditions likely would have prevented a launch.
“This is a brand new rocket,” said Bill Nelson, the NASA administrator, during an afternoon news conference. “It’s not going to fly until it’s ready.”
If launch can’t happen over Labor Day weekend, the rocket will have to return to the giant vehicle assembly building, essentially a rocket garage. A trip there would probably mean a delay of a month or more.
NASA officials said it was important to prudently approach each problem as it arose and not rush decisions that could lead to catastrophic failure.
“We’re going to give the team time to rest, first of all, and then we’ll come back fresh tomorrow and re-evaluate what we learned today and then develop a number of options,” said Mike Sarafin, manager of the Artemis mission. “It’s too early to say what the options are.”
Had it taken off, the flight would have capped off a strong summer for NASA, which ignited the world’s imagination when it released the first views of the cosmos captured by the mighty James Webb Space Telescope in early July.
Instead, NASA engineers, VIP spectators, and the general public were disappointed, but many were sympathetic.
That included Ms. Harris, who was scheduled to give a speech after the launch of Artemis I. Instead, she spoke to reporters on Monday after NASA canceled the flight.
“Innovation requires this kind of moment where you try something that has never been done and then you regroup,” he said. “And you find out what the next step is to get to the ultimate goal, which for us is to go to the moon and show how humans can live and work on the moon.”
Camille Calibeo, 25, who studied aerospace engineering in college, woke up around 2 am to board a boat for a prime view of the launch pad. She said that she expected the launch to still happen in the next few days. “There are so many people here and the excitement was crazy and definitely sad,” she said, “and I hope I can stay.”
kendal van dyke, 46, a senior program manager at Microsoft who lives in Orlando, and members of his family were ready to watch the launch from the NASA Causeway. Although disappointed, he emphasized that canceled launches were a standard risk in spaceflight.
“It’s not about captivating people. It’s about getting billions of dollars worth of hardware into space safely,” Van Dyke said. “Sometimes it works and sometimes it doesn’t, but that’s okay. We had a good experience and were able to spend some time together.”
Six of his seven siblings traveled from across the region to watch the launch together and commemorate their father, who died in November and worked as a contractor on the Apollo program installing audiovisual equipment to monitor astronauts on the launch pad. Several of his brothers now also work in the space industry.
“We thought it would be a great way to celebrate his passing and the family’s accomplishments,” said Mr. Van Dyke.
It is not uncommon for technical problems to arise during the first launch attempts. In 1981, the first space shuttle, Columbia, was on the launch pad with two astronauts strapped in for the first launch into orbit, but the countdown stopped due to a computer glitch. Columbia successfully launched on the second attempt two days later.
For the Space Launch System rocket, the countdown began on Saturday. Despite several lightning strikes at the launch site on Saturday afternoon, the countdown continued smoothly for most of the weekend. Then early Monday morning, the threat of nearby thunderstorms caused a 45-minute delay before liquid oxygen and liquid hydrogen could begin flowing into the rocket’s propellant tanks.
Another problem arose when a leak was detected in a hydrogen fuel line that connects to the bottom of the rocket. That was the recurrence of a problem that occurred during a practice countdown in April.
Engineers were able to fix that problem and filling the hydrogen tank resumed.
The engine issue that surfaced later in the countdown also involved hydrogen, but in a different part of the rocket. In the last part of the launch countdown, some liquid hydrogen and liquid oxygen are diverted to flow around the four engines to cool them down and prepare them for firing.
Three of the four engines were fine, but in the fourth, a hydrogen line didn’t seem to open properly and one of the engines wasn’t as cold as the others.
This was the first test of engine cooling, which usually occurs 4 minutes and 40 seconds before launch. Dress rehearsals of the countdown procedures earlier this year were designed to catch such problems, but were interrupted by technical problems. As a result, engine cooling was not tested. But mission managers believed the rocket had passed critical test objectives and continued preparations for launch.
For Monday’s countdown, a relaxation test was added at an earlier point to allow for troubleshooting should a problem appear. Mission managers recognized the risk.
“That’s something we’re going to demonstrate, from start to finish, for the first time on launch day,” Sarafin said last week after the mission team decided to go ahead with the launch attempt. “And if we don’t prove it successfully, we’re not going to pitch that day.”
Sarafin turned out to be right.
Kenneth Chang reports from the Kennedy Space Center and Christine Chung from New York. Zolan Kanno-Youngs contributed reporting from Washington.