NASA to conduct elaborate dress rehearsal with new megarocket this weekend

Photo by Loren Grush / The Verge

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

The Space Launch System, or SLS, is the agency's new flagship rocket, designed to carry people and cargo into deep space. It is meant to be a lead role in NASA's initiative to send the first woman and the first person of color to the moon by 2020. Capable of lifting nearly 60,000 pounds of cargo to the Moon, SLS is designed to launch NASA's new crew capsule, which will carry future astronauts bound for the lunar surface.

SLS needs to launch before all that can happen. The first flight, called Artemis I, is a rehearsal. On a four- to six-week mission around the Moon, the rocket will launch without any crew inside, showcasing the vehicle's capabilities. NASA wants to do a wet dress rehearsal before that can happen. The term "wet" refers to the fact that NASA flight controllers plan to fill the rocket's tanks with liquid propellant just as they will on launch day.

It has been nearly a decade in the making. NASA and Boeing have been working on SLS since the early 2010s, and there have been many delays and cost overruns along the way. On March 17th, the SLS rocket rolled out of NASA's Vehicle Assembly Building and made its way to Kennedy Space Center in Florida. The LC-39B was used for multiple launches of the Space Shuttle.

Image: NASA

NASA wants the infrastructure surrounding the SLS to work together for the first time now that it will be the primary home. The various tanks and structures used to funnel the cryogenic propellant into the rocket, as well as the massive mobile launch platform that is used to stabilizing the rocket during launch, are all included.

NASA is testing the abilities of the large army of flight controllers. Since this is the first time everyone will be working with this equipment, there will be some issues to be worked out.

The launch team will arrive at their stations at 5PM. After that, the flight controllers will power up SLS and Orion. The excitement doesn't really start until the morning of Sunday, April 3rd, when the team decides if they are ready to proceed with fueling the vehicle. They will fill the SLS's tanks with liquid oxygen and liquid hydrogen and replenish them over the course of the day as the propellant inevitably burns.

After fueling, flight controllers will count down to a time that will reach the terminal count. The support teams will switch to internal power at six minutes before T-minus zero. The teams will manually cut off the launch when the clock hits 33 seconds. They will attempt a second launch attempt if there is a delay on launch. They will go through terminal count and eventually reach T-minus 10 seconds before cutting things off again.

How to follow

NASA plans to give detailed updates on its Artemis blog and provide dispatches on social media during the test. The live views of the rocket will be on NASA's channels.

NASA will not be providing live commentary or live audio of the loop for the rehearsal. The agency cited restrictions surrounding the release of information about how rockets operate, which falls under the purview of ITAR. ITAR is used by the US State Department to control the export of technologies that can be used to make weapons. If a technology is listed on the US Munitions List, you can't export it to a foreign country or foreign national, but you need to get approval to do so.

Many of the same technologies used to build rockets are also used to create intercontinental ballistic missiles that can transport nukes. NASA does not plan on exporting the SLS rocket to another country, but ITAR does regulate the release of technical data used to make and operate rockets.

NASA is concerned about releasing valuable information about the SLS, as adversaries may use that information to create weapons of their own. We have to be very careful when sharing data for the first time.

Image: NASA

It is a curious position for a number of reasons. Most ICBMs these days run on solid propellants, while the SLS runs on liquid propellants. The United Launch Alliance, which uses liquid propellants in its spaceships, has made its countdowns public for the last decade without running afoul of ITAR. There are exceptions for releasing technical data if they are already in the public domain.

Jack Shelton, a lawyer specializing in ITAR at Aegis Trade Law, writes in an email that liquid rocket fuel can be found in any number of patent filings and publications. Many of these are technological secrets that the US government might not want China to have.

ITAR restrictions have become more strict since NASA launched the Space Shuttle. It is possible that NASA received new guidance from the State Department about not releasing this kind of technical data to the public. The definition of technical data is vague and subject to interpretation, which can evolve based on current events and emerging technologies. If the State Department decides that information falls under ITAR, the agency could get in trouble.

NASA is blaming the lack of public information on the fact that the SLS is very new, but the agency does plan to expand its coverage for the Artemis I launch by releasing air-to-ground communications.

Hardcore fans can follow updates online. It is also a dress rehearsal for NASA's social team, which will be working overtime when Artemis I does launch.