New technical problems for SLS?
A new GAO report [pdf] issued yesterday has revealed that SLS engineers are concerned that the rocket’s core stage will develop leaks during its first full test, hopefully scheduled for this year.
[T]he new “Assessments of Major NASA Projects” report released on Wednesday contains what seems to be an entirely new bit of information about the Space Launch System rocket NASA is developing for deep space exploration. The report asserts that engineers at NASA and the SLS rocket’s core-stage contractor, Boeing, are concerned about fuel leaks.
Earlier this year, NASA moved the big rocket’s core stage to a test site at Stennis Space Center in southern Mississippi. Before the COVID-19 pandemic temporarily halted work, NASA and Boeing teams were working toward a critical summer exercise. During this “green run” test, the clamped-down rocket will ignite its engines and burn for about eight minutes to simulate an ascent into orbit.
“Program officials indicated that one of the top remaining technical risks to the green run test is that the core stage may develop leaks when it is filled with fuel,” the report states on page 82. “According to these officials, they have conducted extensive scaled testing of the gaskets and seals used in the core stage; however, it is difficult to precisely predict how this large volume of liquid hydrogen will affect the stage.”
My god, for them to think that the core stage might leak when it is filled with fuel for the first time illustrates the entire bankrupt nature of this entire project. This is why you do tank tests early in the process (as SpaceX has been doing with Starship), so that you don’t get surprised late in the game.
The report also notes further issues with the Orion capsule.
The Orion program plans to reduce the 7-month-long pre-launch processing period by 1.5 months. The program plans to use a mass simulator—instead of the Orion spacecraft—to conduct some prelaunch tests that would otherwise be done after integrating Orion with SLS—providing the program with extra time to complete work before delivering Orion for integration and further testing according to officials. With this shortened process, the program has only 1 week of schedule reserve remaining to the November 2020 launch date, and program officials have said this date will likely be delayed
I must remind everyone that Lockheed Martin got the contract to build Orion in 2005. They have had fifteen years to build this one capsule, and will still deliver it late.
Personally, I hope SLS leaks. If it does, it will force a very long new delay to the program, and very well might finally force Congress and the Trump administration to face reality and cancel it.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
A new GAO report [pdf] issued yesterday has revealed that SLS engineers are concerned that the rocket’s core stage will develop leaks during its first full test, hopefully scheduled for this year.
[T]he new “Assessments of Major NASA Projects” report released on Wednesday contains what seems to be an entirely new bit of information about the Space Launch System rocket NASA is developing for deep space exploration. The report asserts that engineers at NASA and the SLS rocket’s core-stage contractor, Boeing, are concerned about fuel leaks.
Earlier this year, NASA moved the big rocket’s core stage to a test site at Stennis Space Center in southern Mississippi. Before the COVID-19 pandemic temporarily halted work, NASA and Boeing teams were working toward a critical summer exercise. During this “green run” test, the clamped-down rocket will ignite its engines and burn for about eight minutes to simulate an ascent into orbit.
“Program officials indicated that one of the top remaining technical risks to the green run test is that the core stage may develop leaks when it is filled with fuel,” the report states on page 82. “According to these officials, they have conducted extensive scaled testing of the gaskets and seals used in the core stage; however, it is difficult to precisely predict how this large volume of liquid hydrogen will affect the stage.”
My god, for them to think that the core stage might leak when it is filled with fuel for the first time illustrates the entire bankrupt nature of this entire project. This is why you do tank tests early in the process (as SpaceX has been doing with Starship), so that you don’t get surprised late in the game.
The report also notes further issues with the Orion capsule.
The Orion program plans to reduce the 7-month-long pre-launch processing period by 1.5 months. The program plans to use a mass simulator—instead of the Orion spacecraft—to conduct some prelaunch tests that would otherwise be done after integrating Orion with SLS—providing the program with extra time to complete work before delivering Orion for integration and further testing according to officials. With this shortened process, the program has only 1 week of schedule reserve remaining to the November 2020 launch date, and program officials have said this date will likely be delayed
I must remind everyone that Lockheed Martin got the contract to build Orion in 2005. They have had fifteen years to build this one capsule, and will still deliver it late.
Personally, I hope SLS leaks. If it does, it will force a very long new delay to the program, and very well might finally force Congress and the Trump administration to face reality and cancel it.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Personally, I hope SLS leaks.
Delicious. Yeah, it would help.
Actually I’d like SLS to launch, fly to a safe distance but still easily visible and go BOOM. Wouldn’t that be the perfect end to it? I’d rather it blew up the launch pad like the N1 but the risks are way, way too much.
Yes. Elon is going to need that pad soon and it would be nice if it wasn’t any more of a fixer-upper situation than it already is.
If it did, it wouldn’t be the first time there was a leak with a government project.
I don’t see anything there that provides a basis for fearing a leak, that might just be a “this is what could go wrong” CYA prep. But I wouldn’t be surprised at all if there are leaks, contaminants, and whatever other unforeseen problem that will delay things yet again.
A simple (I think) question. How is it that the Saturn V could be designed and built in a relatively short period of time when much of the technology that was used then was relatively new and untried?
Now, almost sixty years on, the SLS seems to present insurmountable technological problems, even though one might suspsect that everything from materials science to the digital modeling of structural components has advanced over the intervening decades. (Hummm. Are we building better aircraft today than in 1965? In the case of Boeing, perhaps not.)
Have the laws of physics and the nature of materials changed?
Have the technology and techniques that created and built the Saturn rockets somehow become “lost” to present day engineers? (Sort of along the lines that nobody around today knows how the pyramids were built or how the Romans made their cement?)
Are our engineers (with vast computational power behind them compared with the 1960s) less skilled / capable than their grandfathers?
Has there been no real progress in the field of rocketry in the last five decades?
Oh, wait. SpaceX *does* seem to be building rockets using all of the new methods and technologies that have evolved over the last 50 years. Perhaps there HAS been progress in this field over the ensuing decades, but the folks trying to build the SLS just weren’t interested in using it…
Milt, you kind of get it backwards. The technology has advanced by leaps and bounds. Robotic friction-stir welders, carbon composites, etc. etc. And with those changes, everything is new again. And we’re faced with the conundrum that there isn’t much expertise around in the old way of brute force aluminum and steel welding, but the new robotic high-tech solutions are bleeding edge and not really ready for prime time. One could say that Boeing is trying to milk the government not just for raw cash, but also for R&D on industrial processes.
SpaceX started down that path, and then changed their minds, and are spinning back up on the “old” way of doing things, with lots of guys out on the line swinging around on cranes with welders on bare steel. The product won’t be as nifty or as high-tech, but it will actually exist and get the job done at great scale.
Milt asked: “How is it that the Saturn V could be designed and built in a relatively short period of time when much of the technology that was used then was relatively new and untried?”
Dave has it right. Few, if any, welders know some of the welding techniques used on the Saturns. We cannot make another Saturn V if we wanted to. However, Saturn’s technology is old. Its first stage F1 engines were powerful but inefficient. SpaceX’s Raptor engines are much more efficient and about 1/3 as powerful.
Apollo’s short development period was due to it being a national priority with all the resources of the nation behind it. SLS is Congress’s baby, and although it has the resources of Congress behind it, there is no sense of urgency. Congress seems to be using it only as a jobs program and not as a national resource to drive us into the depths of space.
On the other hand, SpaceX has set space exploration as a priority (hence the company’s name, Space Exploration Technologies Corp). Although its launch vehicles are not a national priority and SpaceX only has its own profits, employees, vendors, and facilities as resources, its philosophy is rapid development. Getting a product to market sooner rather than later is important to them, and this means that they sometimes don’t maximize efficiency (like they didn’t with Apollo’s F1 engines) in favor of rapid development in order to, as David put it “get the job done.”
Rapid development and innovation are why so many people are enthusiastic about SpaceX. Taking so long with Shuttle-age technology and hardware is why so few people are enthusiastic about SLS. Orion, on the other hand, has been hampered by the slow development of SLS — finishing it earlier than SLS would mean that those who built it would be on other projects (or at other companies) and would have to be replaced by people who knew little about it in order to operate and service it.
David wrote: “I don’t see anything there that provides a basis for fearing a leak”
See page 82: “Program officials indicated that one of the top remaining technical risks to the green run test is that the core stage may develop leaks when it is filled with fuel. According to these officials, they have conducted extensive scaled testing of the gaskets and seals used in the core stage; however, it is difficult to precisely predict how this large volume of liquid hydrogen will affect the stage.”
This may be another difference between SpaceX and SLS. SpaceX seems to be testing these kinds of things early, while SLS seems to have held off on this particular test until late in the development program.