Thu. Mar 23rd, 2023

For most of the past five years, NASA’s space launch system has largely been a PowerPoint rocket, made up of designs on computers and disparate hardware in various stages of development across the United States. But now the massive SLS rocket is starting to converge, and senior NASA executives are optimistic about the future.

“This is an amazing period in American space travel,” Bill Gerstenmaier, chief of human spaceflight for NASA, said at a meeting of the agency’s advisory board last week. “I’m starting to see a real shift from just kind of hardware development to almost a flight rhythm. The amount of work is just amazing.” He added that with “about” two years to go before the first launch of SLS and the Orion spacecraft, the agency will begin testing flight hardware.

Barring further delays, the first launch of SLS will take place between September and November 2018. So far, NASA has mainly designed and built individual components of the massive rocket, which will initially be capable of carrying 70 tons to low orbit. earth, but could eventually grow into a 130-ton rocket. Now, however, the focus is on testing that hardware and, later next year and in 2018, it will start integrating for launch.

Historically, this is during development programs where the most problems and potential delays occur, as systems may not work together exactly as intended. And the SLS missile has many different parts. For the core stage, which provides the primary thrust, there is the liquid oxygen tank, the intermediate tank, the liquid hydrogen tank and the engine compartment. The core stage also houses the vehicle’s avionics. On the side of the core stage are two solid rocket boosters, which provide the initial thrust of the path. Then, on top of the core stage is the upper stage that provides thrust later in flight. Finally, there’s the payload itself, the Orion spacecraft and its service module, which are also under pressure to make it to the 2018 flight.

Gerstenmaier acknowledged this during his remarks last week. “We have a reasonable margin in our schedules,” he said. “It is foolish to think that there are no problems ahead, that is the nature of a development program. I guarantee you there will be more things to come. But we are in the process of building a robust schedule that can handle the challenges ahead.”


It costs NASA a lot of money to do all this work. The agency has committed to spending $23bn (~£17bn) from 2011 through 2018 to get SLS and Orion ready for first flight, and that doesn’t include another $9bn spent before 2011 during the Constellation program, which began work on Orion and a precursor to the SLS.

NASA has not said how much it will cost to continue development of these launchers beyond 2018, nor has it, crucially, specified the amount of ongoing or fixed costs once the SLS begins flying every two years in the mid-2020s . . This fixed cost for the space shuttle was about $2.5 billion a year, meaning a lot of spending was spent whether the vehicle was flying or not. NASA greats like Chris Kraft have warned that the fixed costs of the SLS will “eat NASA alive”.

Accordingly, one of the major concerns when it comes to the SLS and Orion is that the vehicles will cost so much to build and fly, leaving very little money to develop hardware for meaningful missions, such as stations in lunar orbit or flee beyond. the Earth-Moon system. “I can understand where one would come to that conclusion,” Bill Hill, the chief official overseeing SLS and Orion development for NASA, told Ars in an interview. “We are in the process of defining targets for flight testing, and we believe we can do so at least for now with the current budget level. We’re trying to set our pace.”

“Better than I expected”

But to reach those test targets in space, NASA must first complete them on the ground. At the Michoud Assembly Facility, Hill said, work is underway on “qualifying” tanks for both liquid hydrogen and liquid oxygen. These tanks will be shipped to the Marshall Space Flight Center for testing later this year. Meanwhile, work is also underway on the actual fuel tanks that will be used for the 2018 test flight, Exploration Mission-1. In addition, four of the 10 segments for the flight test solid rocket boosters have been cast, and main engine test firing continues.

After these tests and assembly, a big moment will come for the SLS program in the fall of 2017. At that time, NASA is planning a “hot fire test” of the entire core stage at the Stennis Space Center in southern Mississippi. During this test, the core stage is clamped down while a full thrust test of the launch system is performed. This test will go a long way toward proving that the large, 60-meter-tall core stage is ready for spaceflight.

Despite concerns about cost and low airspeed, Hill said NASA considers the SLS rocket and Orion spacecraft “fundamental” to its efforts to continue deep space exploration. And all things considered, he said NASA is doing well with the budgets provided by the president and Congress. “With the funding levels we have, we’re doing much better than I expected,” he said.

List image by NASA

By akfire1

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