NASA will hold an elaborate dress rehearsal with a new mega-rocket this weekend

Over the next three days, NASA is holding an elaborate dress rehearsal with its massive new rocket, the Space Launch System – practicing all the major steps the agency will need to perform when the vehicle launches for the very first time. It’s a major milestone for the rocket’s development and one of the last major tests it must undergo before the vehicle can be cleared to fly this summer.

The Space Launch System, or SLS, is the agency’s new flagship rocket, designed to transport people and cargo into deep space. He is expected to play a leading role in NASA’s Artemis program, the agency’s initiative to land the first woman and first person of color on the Moon by the mid-2020s. Lifting nearly 60,000 pounds of cargo into orbit beyond the Moon, SLS is designed to launch NASA’s new crew capsule called Orion, which will ferry future astronauts to the lunar surface.

But before any of that can happen, SLS just needs to get started. Its first flight, called Artemis I, is also something of a repeat. The rocket will launch Orion – without any crew inside – for a four to six week mission around the Moon, showcasing the vehicle’s capabilities. But before this can happen, NASA wants to go through all the steps leading up to the launch, what is called a wet dress rehearsal. The term “wet” refers to the fact that NASA flight controllers plan to run through the entire launch countdown, even filling the rocket’s tanks with ultra-cold liquid propellant, as they will on the day. of the launch. “This closely follows the launch countdown,” Charlie Blackwell-Thompson, NASA’s Artemis launch director, told a rehearsal news conference. “There are some minor differences, but they are, in fact, minor.” Of course, the main difference is that the countdown won’t actually reach T-minus zero, so there won’t be an actual launch.

It’s a test that’s been going on for almost a decade. NASA and its prime contractor Boeing have been working on SLS since the early 2010s, and there have been many delays and cost overruns along the way. The SLS rocket finally exited NASA’s iconic Vehicle Assembly Building on March 17, fully stacked, and slowly made its way to its main launch pad at Kennedy Space Center in Florida. Called LC-39B, the launch pad was used for an Apollo launch as well as several Space Shuttle launches.

NASA’s mobile launch pad at KSC
Image: NASA

It will now be the main headquarters of the SLS, and NASA wants to ensure that the infrastructure surrounding the SLS can work together for the first time. This includes all ground support systems, such as the massive mobile launch pad used to stabilize the rocket during launch, as well as the various tanks and structures used to funnel cryogenic propellant into the rocket. “There are thousands of components on the mobile launch vehicle that need to work,” Tom Whitmeyer, deputy associate administrator for NASA Joint Exploration Systems Development, said at the press conference.

In addition to testing the technology, NASA is also testing the capabilities of the large army of flight controllers. Since this is everyone’s first time working with this equipment and following these procedures, there are bound to be a few issues to resolve.

Things will start this afternoon at 5 p.m. ET, when the launch team arrives at their stations. Shortly after, the flight controllers will power up SLS and Orion. The excitement doesn’t really start until the morning of Sunday, April 3, however, when the team decides if they’re ready to refuel the vehicle. If they go, they will start filling the tanks of the SLS with cryogenic liquid oxygen and liquid hydrogen and will continue to fill the tanks during the day as the propellant inevitably boils.

After refueling, flight controllers will count down to a predetermined “launch” time, eventually reaching the final count. Just six minutes before T-minus zero, support crews will switch Orion to internal power, followed by the rocket itself. The countdown will continue until T-minus 33 seconds, at which time teams will manually abort the launch. They will then go through a refresher, when they try to run through the final part of the countdown again, testing the team’s abilities to attempt a second launch attempt in the event of a delay on launch day. Again, they’ll go through the terminal count and eventually reach T-minus 10 seconds before cutting things off again.

How to follow

For those interested in following the test, NASA plans to provide detailed updates on its Artemis blog, as well as send dispatches on Twitter. Live views of the SLS rocket will be shown on one of NASA’s YouTube channels.

However, in a somewhat controversial move, NASA will not provide live commentary or live audio of the countdown loop for the rehearsal. The agency cited restrictions surrounding the disclosure of information about the operation of rockets, which falls under the jurisdiction of the ITAR, or International Traffic in Arms Regulation. Enforced by the US State Department, ITAR is used to control the export of certain technologies that can be used to manufacture weapons. Generally, if a technology is listed on what is called the United States Ordnance List, you cannot export that technology to a foreign country or foreign national, or you must obtain approval to do so.

Rockets are on the US munitions list because many of the same technologies used to build rockets are also used to create intercontinental ballistic missiles capable of carrying nuclear weapons. And although NASA does not plan to physically export the SLS rocket to another country, the ITAR also regulates the release of what is known as “technical data” – essentially the blueprints and other knowledge used to manufacture and operate the rockets.

Regarding the SLS, NASA says it is concerned about the release of valuable information about its countdown sequence, as adversaries can use this information to create their own weapons. “Generally what they’re looking for is timing and sequencing data, flow rates, temperatures, how long it takes to do certain tasks,” Whitmeyer said. “It is considered important information by other countries. So we have to be very careful when sharing data, especially for the first time. »

Charlie Blackwell-Thompson in the KSC shooting range
Image: NASA

This is a curious position for several reasons. On the one hand, the SLS operates with liquid propellants, whereas most ICBMs these days operate with solid propellants. Additionally, commercial companies like SpaceX and United Launch Alliance (both of which use liquid propellants in their spacecraft) have released their countdowns over the past decade without clashing with ITAR. Within the ITAR, the regulations state that there are exceptions for the publication of technical data if it is already in the public domain.

“The existence of liquid rocket fuel can be found in a number of patent filings and publications,” writes Jack Shelton, an ITAR attorney at Aegis Trade Law. The edge in an email. “But there is certainly a lot of other information related to SLS that is not in the public domain. Many of them are technological secrets that the US government might not want China to get their hands on.”

NASA notes that ITAR restrictions have become stricter since the agency used to launch the space shuttle. It is also fully NASA may have received further guidance from the State Department regarding the non-disclosure of this type of technical data to the public. There may be a definition of technical data, but it remains quite vague and always subject to interpretation, which can certainly evolve according to current events and emerging technologies. The agency could be in trouble if it releases information that the State Department decides to report ITAR.

NASA also blames the lack of public information on the fact that the SLS is very new, but the agency plans to expand its coverage for the eventual Artemis I launch by releasing air-to-ground communications. “We’re actually going to talk to the export control people and share with them what we think is acceptable data, and then they’re going to verify that it’s acceptable data, and hopefully at launch we’ll ‘ll have a really good understanding,” Whitmeyer said.

For this weekend, hardcore fans can follow updates online. It’s also a dress rehearsal for NASA’s social team, which is sure to be working overtime during the launch of Artemis I.

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