Monday , June 5 2023

The SLS rocket may have slowed development of on-orbit refueling for a decade


The Space Launch System (SLS) rocket oxygen tank structure test was manufactured and stacked in June 2019 at NASA's Michoud Assembly in New Orleans.
To enlarge / The Space Launch System (SLS) rocket oxygen tank structure test was manufactured and stacked in June 2019 at NASA's Michoud Assembly in New Orleans.


Almost a decade ago, when Congress directed NASA to build a large rocket based on a space-age spacecraft called the Space Launch System, the agency also quietly put its back burner to work on developing in-space refueling technology.

It has long been rumored in airspace that funding for NASA's efforts to develop so-called propulsion tanks, and the ability to store and deliver cryogenic rocket fuel into orbit, has been hampered by the threat it posed to the SLS rocket and its main carrier. , Boeing.

Finally, if smaller, cheaper rockets could launch rocket fuel and stack it in low-Earth orbit for staged missions to the Moon or beyond, why would NASA have to spend $ 2 billion a year to develop the SLS rocket? Why not just use that money to buy commercial launches, starting from the Delta IV Heavy and then the Falcon Heavy, and building a research program around existing capabilities? It would probably be faster and cheaper.

Now, thanks to comments on Twitter from George Sowers, a physicist in the middle of this controversy, we have confirmation of sorts. In the early and mid-2010s, Sowers led the advanced program at United Launch Alliance (ULA), the rocket company owned by Boeing and Lockheed Martin. Proprietary repositories were among the technologies he worked on. Sowers is now a professor at the Colorado School of Mines.

ULA works on deposits

One of ULA's key assets was its upper Centaur, and the company wanted to build an innovative version that could be refurbished in space and reused, called Advanced Cryogenic Development Stage, or ACES. As part of this development, in 2011, ULA proposed an in-space spacecraft test to NASA that would cost less than $ 100 million.

"We have released a series of papers showing how a repository / refurbishing architecture would enable a human research program using existing (at the time) commercial rockets," Sowers tweeted on Wednesday. "Boeing has been furious and tried to kill me. It will thank my CEO for protecting me. But we were banned from even saying the word out loud. The sad part is that ULA has done a lot of work in that area and was able to own the market. of supply / deposition, enriching Boeing (and Lockheed) in the process. But it was closed because it threatened SLS. "

United Launch Alliance concept for propellant deposition based on its ACES upper stage. "Src =" "width =" 941 "height =" 709

United Launch Alliance concept for fuel deposition based on its ACES upper stage.

United Launch Alliance

A Boeing spokesperson said he would investigate these comments, and Ars will update this story if Boeing responds. United Launch Alliance CEO Tory Bruno told Ars in late 2018 that ACES development has remained "out of the way" on the company's path.

Sowers' suggestion that "deposits" should not be publicly in line with observations at the time by a U.S. Senator from Alabama, Richard Shelby, had said NASA should stop talking about propulsion tanks. The NASA spaceflight center, which manages the development of the SLS, the Marshall Space Flight Center, is based in Alabama.

Can't I have a Falcon Heavy?

Publicly, in the early and mid-2010s, proponents of the large SLS rocket were critical of repositories as they claimed the technology was not ready for the premature. Then-NASA Administrator Charles Bolden also said that the agency cannot plan its research plans around the Falcon Heavy and propulsion tanks because the SpaceX rocket was not a true rocket.

"Let's be very honest again," Bolden said in a 2014 interview. "We don't have a commercially available heavy lift vehicle. Falcon 9 Heavy may have been a day ago. It's on the drawing board now. SLS is real. You saw it in Michoud. We're building the core stage. We have all the engines ready to be put on the test stand at Stennis … I don't see a device for Falcon 9 Heavy, except he will take three Falcon 9s and join them and that will become the Heavy. it's so easy on a rocket. "

SpaceX privately developed the Falcon Heavy rocket for about $ 500 million, and it flew its first flight in February 2018. It has now flown three successful missions. NASA has spent about $ 14 billion on the SLS rocket and related development costs since 2011. It is not expected that a rocket will fly until at least mid or late 2021.

The issue of repossession has flared up this week as NASA's Space Technology program announced it would work with SpaceX, as part of a Space Act agreement in which no funds are exchanged, to help develop an on-orbit refueling for a Starship vehicle. the company. It marked the first time NASA truly formally recognized Starship. It also signaled that NASA is now ready to take the concept of re-orbit refueling seriously. This probably spurred senior officials in the White House. Vice President Mike Pence, who heads the National Space Council and supports business efforts, even mentioned propulsion depots in talks.

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