Contamination found in shuttle engines to be used by SLS

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Now we know why the first launch is likely delayed: It appears that contamination has been found in the used and refurbished shuttle engines that the Space Launch System is using.

A “routine quality assurance inspection” of the core stage, he said, discovered contamination in tubing in the engine section of the core stage, which hosts the vehicle’s four RS-25 main engines and associated systems. That contamination turned out to be paraffin wax, which is used to keep the tubes from crimping while being manufactured but is supposed to be cleaned out before shipment.

“The prime contractor determined the vendor was not fully cleaning the tubes and it was leaving residue in the tubes,” McErlean said. “This was retained as a requirement in the prime contractor’s spec, but it was not properly carried out.” Boeing is the prime contractor for the SLS core stage, but he did not disclose the vendor who provided the contaminated tubing.

The contamination was initially found in a single tube, he said, but later checks found similar residue in other tubes. All the tubing in the core stage is now being inspected and cleaned, a process he said is not straightforward because of the “mass of tubing” in the engine section and also because cleaning is a “non-trivial process.”

Some obvious questions immediately arise:

1. These engines were previously flown on the space shuttles, numerous times. How did the paraffin wax, used “to keep the tubes from crimping while being manufactured,” remain in the tubes during all those shuttle flights?

2. Assuming the tubes were a new addition or replacement during the refurbishing process, it still seems astonishing that a subcontractor could be so lax. Did they really believe the wax did not need to be thoroughly cleaned?

3. While they have admitted that they will likely have to delay the launch because of issues with the core stage, why do they deny this contamination problem is the cause? More important, how much is it costing to fix? And how much time are they actually losing to fix it?

4. Finally, this is only one of many similar problems that we have seen with this entire project. Boeing and NASA have gotten so far about $40 billion to build this rocket, and have been working on it since 2006, more than a dozen years ago. Furthermore, they supposedly are building it using shuttle equipment in a Saturn rocket-type design in order to save money and time. Instead, they have wasted billions and taken more than three times longer than it took us to win World War II to get to a point where the program still has not flown.

Does anyone really believe this project is anything but a huge boondoggle? And if so, can they please tell me how it will be possible for the United States to really explore the heavens with a project run this incompetently?



  • Localfluff

    When rocket engines stand on the shelf for decades and decades, old age maybe makes them earwax?
    Sci fi people like to talk about generational space travel. Well, we have it right here and now! Soyuz from 1965 as the only crewed launcher outside of China, and NASA looking longingly back at that concept. Using some ancient engines they found in the storage (like the first version of Antares used Soviet engines for the N-1 Moon failure). Never making up anything new, that might be or become politically sensitive. Just looking back. That’s governmental rocket science, in human spaceflight anyway, robotics has such a great track record as contrast to show what would’ve been possible.

  • Dick Eagleson

    It sounds to me as though the paraffin contamination is in the tubing that carries LOX and/or LH2 from the SLS core stage’s tankage to the engines. These would be newly manufactured parts and would not have flown previously.

    Perhaps Boeing used a subcontractor whose experience is mostly in providing tubing for aircraft applications, not rocket plumbing. Paraffin in a line carrying jet fuel would quickly dissolve and present no problem. Paraffin in a line carrying LH2 would freeze so hard that pieces spalled off the tubing walls by launch vibration could potentially damage high-speed turbomachinery inside the engines. Paraffin in a line carrying LOX could cause an explosion.

    Such explosions have been known to occur when LOX tank trucks have been involved in traffic accidents, sprung leaks and LOX has spilled onto asphalt paved surfaces. Asphalt has a higher molecular weight than paraffin wax and is correspondingly more difficult to ignite. Paraffin is easier to ignite and, inside a piece of rocket plumbing, would be subjected to rapidly moving LOX flow at very high pressure, neither of which apply in traffic accident-caused LOX spills. An SLS core stage with paraffin in its LOX delivery plumbing could cause a launch-time explosion that would make SpaceX’s Amos-6 misadventure look like a damp squib by comparison.

    The “old reliable” legacy contractors are definitely old, but “reliable” seems increasingly to be equal parts nostalgia and vainglory.

  • Col Beausabre

    It all brings to mind Allen Shepherd’s remark about everything being made by the lowest bidder. And of course, no one will be held accountable and demoted or fired – despite what I learned as a Freshman ROTC cadet, “The commander is responsible for all the unit does or fails to do.”

  • Edward

    On your fourth question, all projects run into trouble, and even when I was working on space instruments we would have multiple schedule-slipping problems rear their ugly heads. This really is to be expected, and managers should be setting their schedules to allow for problem solving, especially on development projects. One difference between those instruments and SLS is the order of magnitude of cost when a delay happens. Another difference is the amount of delay.

    I know that I have just sounded like I am defending SLS’s problems, and maybe I am, but to counter what I just said, the article states: “We have a lot of mitigation activities in work across the board.

    That sounds like there is more trouble on SLS than should be expected. Coming from a space agency that designed, built, tested and successfully used a huge rocket, spacecraft, and lunar lander in under a decade, we have great expectations from that agency. Are these expectations unjustified?

    Maybe, but I don’t think so. NASA should have learned how to manage a large project, even one that is unique in history.

    Among the differences between then and now is that on Project Apollo there was a sense of urgency, which produced a requirement for high quality control on first production items. Planning had to be right the first time, design had to be first rate, manufacturing had to be accurate, and test had to only rarely find problems. The budget may have been larger for Project Apollo, but they had to build everything from scratch. Most of those things had never been done before, and no one knew how to do them.

    Today, there is not nearly as much national pride in SLS as there was in Apollo (or as much as in Falcon rockets, for that matter), and there likely is not as much pride felt by the subcontractors or their workers, either. Back in the 1960s space was virtually everywhere in American culture; today it is an afterthought — mostly the thought is that it is merely an everyday tool, such as GPS.

    Apollo had its difficulties, but it still succeeded within schedule. The Space Shuttle also had some delays, but it ultimately worked, although not as well as intended. The ISS took 15 years to start getting hardware into space, but there was a lot of politics involved, creating that lag. A part of SLS’s problem was also political, since it replaces the politically cancelled Constellation project. The James Webb Space Telescope is also suffering from problems, costing almost an order of magnitude more than originally expected.

    This brings up another difference between the 1960s and now: the politicians holding the purse strings today just are not in a hurry to get anything done, and don’t seem bothered when things don’t get done right. Meanwhile, commercial companies are working hard to get things going sooner rather than later and are trying hard to get it done right at lower cost.

    Civil space went from a “can do” attitude in the 1960s to a “no can do” attitude. It seems to me that the NewSpace companies are bringing back “can do.” Even when at first they don’t succeed, as with Armadillo Aerospace, the people of New Space try, try again, as with Exos Aerospace. (Also compare Rotary Rocket, XCOR, and Agile Aero.)

    Theoretically, we should have learned a lot of lessons between the 1960s and today, but it seems as though those lessons were lost on NASA, its contractors, and its subcontractors — and I’m not sure that Congress ever learns anything. It seems as though those who are involved in SLS do not have any sense of urgency or of that 1960s sense of pride in their workmanship.

  • Edward: In writing my post, I provided in question #4 links to a variety of equally embarrassing problems that the SLS program has experienced. In writing it, I was tempted to describe those problems, but got lazy and didn’t. I should have. They were:

    Each of these is unacceptable. All of them is disgusting, and exposes this project for the disaster that it is. If I was an astronaut I certainly would be afraid to fly on it.

    In fact, much of this reminds me of the terrible engineering foolishness that led up to the Apollo 1 fire. As astronaut Frank Borman noted after being a major participant in the post-fire investigation, “Quite frankly, we did not think.”

    I don’t think there has been much thought involved with the entire SLS/Orion project. It has been driven entirely by Congress, and they certainly are not the ones to design a rocket or space capsule. But in this case, they have.

  • Localfluff

    But it sounded like such a great idea for a quick cheap stop-gap after the shuttle was canceled. Just launch the shuttle without the shuttle! Can you do that next time? -Sure, that only makes everything much easier! No development work needed, no new infrastructure. Just more of the same but cheaper. Oh well, and here we are decades later.

  • Ryan

    SLS is a disaster and I don’t Believe it will ever fly. The government motto of a jobs program and no care of what the result is very destructive. The government cannot compete with the private sector such as SpaceX. We can only hope that the Trump administration makes our government space agency like the private sector. I doubt that will ever happen. In the meantime it is a total embarrassment.

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