NASA Live Stream: Watch the Space Launch System Hot Fire Test

NASA has spent years and billions of dollars developing a giant rocket known as the Space Launch System, designed to carry astronauts to the moon and perhaps one day further into the solar system. But the rocket’s first launch, an unmanned test flight that will go to the moon and beyond, won’t take off until at least November.

This Saturday, however, NASA is scheduled to put on a fiery show as it performs a crucial test: firing up the four booster stage engines for up to eight minutes, simulating what would happen during an actual launch into orbit. However, the thruster will remain securely attached to a test bed at NASA’s Stennis Space Center in Mississippi.

The test fire is scheduled for Saturday between 5 and 6 p.m. ET. NASA Television has begun broadcasting coverage of the test, or you can watch it in the embedded video player above.

In the early afternoon, the agency moved the schedule forward an hour to 4 pm, saying that after loading the rocket with propellant, preparations were well under way.

However, the updated time frame was delayed and Alex Cagnola, a NASA engineer, said the test drivers were “working out some problems at the booth,” without describing the cause of the delay or how long it would last.

Jim Bridenstine, the NASA administrator, later said on Twitter that the test was expected “in an hour.”

That could push the intent toward the back end of the window to run the test, which NASA says takes about two hours.

A press conference is scheduled about two hours after the test.

The Space Launch System is the 21st century equivalent of the Saturn V that landed NASA astronauts on the moon in the 1960s and 1970s. Although there are many other rockets available today, they are too small to launch spacecraft that can take people to the moon. (One possible exception is SpaceX’s Falcon Heavy, but a human lunar mission would require two separate launches carrying parts that would later dock in space or go separately to the moon.)

The Falcon Heavy can lift up to 64 metric tons to low Earth orbit. The initial version of the SLS is slightly more powerful, capable of lifting 70 metric tons, and future versions of the rocket will be able to lift up to 130 metric tons, more than the rockets that carried the Apollo astronauts to the moon.

Although the Space Launch System will be expensive (up to $ 2 billion per launch for a rocket that can only be used once), Congress has given it strong financial support so far. Supporters argue that it is important for the government to own and operate its own powerful rocket ship, and parts of the system are built by companies across the country, distributing the economic benefits to many states and congressional districts.

The Space Launch System is a key component for Artemis, the program to get NASA astronauts back to the moon for years to come. Although President Trump promised to make the trip in late 2024, few expected NASA to actually meet that schedule, even before President-elect Joseph R. Biden Jr. was elected.

When NASA announced its plans for the Space Launch System in 2011, the first launch was scheduled for 2016. As is typical of new rocket designs, development ran into technical difficulties, such as the need to develop procedures for welding parts of metal as large as the rocket. NASA also halted work on the rocket for a time last year during the early stages of the coronavirus outbreak.

As the first release date slipped multiple times, the price increased. So far, NASA has spent more than $ 10 billion on the rocket and more than $ 16 billion on the Orion capsule where the astronauts will sit.

In a 2018 audit, NASA’s inspector general blamed poor performance by Boeing, the prime contractor that built the booster stage, for much of the delay. Another 2020 inspector general report said NASA “continues to struggle to manage the costs and schedule of the SLS program.”

The test fire is part of what NASA calls the green run, a series of fully assembled booster stage tests. The same thruster will be used for the first flight into space, so the engineers want to make sure it works as designed before launching it.

As with an actual launch, technical glitches occur. In a previous test, known as a wet dress rehearsal, in which the entire countdown was simulated, except for starting the engines, almost everything went well. But in the last few seconds, one of the thruster valves did not close as soon as expected. It turned out that the temperature was a little lower than expected, and that made the valve a bit more difficult to turn. Since then, the software has adjusted.

The worst case would be if a malfunction resulted in the destruction of the amplifier. That would add years of delay to the program and renew requests for NASA to consider alternatives.

Several other rockets are in development, and some may be close to their first trips into space.

United Launch Alliance, a joint venture between Boeing and Lockheed Martin, may launch its Vulcan Centaur in the fourth quarter of the year. The Vulcan Centaur is the successor to Atlas V, a long-standing workhorse for launching military and NASA satellites. However, that rocket uses Russian-made RD-180 engines, and Congress has grown increasingly wary of relying on technology from a country that is often seen as an adversary.

Blue Origin, the rocket company started by Jeff Bezos, Amazon’s billionaire founder, has also been developing a reusable rocket called New Glenn that would compete with SpaceX’s Vulcan Centaur and Falcon 9 rockets. (Blue Origin will also make money with every Vulcan Centaur launch; that booster uses BE-4 engines made by Blue Origin.)

Most intriguing is the gigantic Starship rocket being developed by Elon Musk’s SpaceX. When mounted on top of a huge booster stage, it would dwarf the Space Launch System, but it would be completely reusable as an airliner. It’s designed to get people to Mars, and SpaceX also won a contract to adapt it to bring NASA astronauts to the surface of the moon.

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Musk engineers have been conducting atmospheric test flights of Starship prototypes at a site in South Texas along the Gulf Coast. During the most recent test, which was streamed live on the Internet, the prototype rocket achieved a number of technical objectives before falling too fast during its landing and exploding in a spectacular explosion. The company appears to be preparing for its next test flight in the next few days or weeks.