Orion heat shield redesigned before its launch?

Chronological Encyclopedia of Discoveries in Space cover

After being in print for twenty years, the Chronological Encyclopedia of Discoveries in Space, covering everything that was learned on every single space mission in the 20th century, has finally gone out of print.

I presently have my last four hardback copies available for sale. The book sold new for about $90. To get your own autographed copy of this now rare collector's item, please send a $120 check (which includes shipping) payable to Robert Zimmerman to

Behind The Black, c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652

"Useful to space buffs and generalists, comprehensive but readable, Bob Zimmerman's Encyclopedia belongs front and center on everyone's bookshelf." -- Mike Collins, Apollo 11 astronaut


"The Chronological Encylopedia of Discoveries in Space is no passionless compendium of information. Robert Zimmerman's fact-filled reports, which cover virtually every spacecraft or probe to have ventured into the heavens, relate the scientific and technical adventure of space exploration enthusiastically and with authority." -- American Scientist

Even before Orion’s first flight next month to test its heat shield, engineers are proposing a major change in the shield’s design and manufacture.

The Orion heat shield’s titanium skeleton and carbon fiber skin was fabricated by Lockheed Martin — the craft’s prime contractor — in Colorado. The skeleton was shipped to Textron Defense Systems in Massachusetts for installation of a fiberglass-phenolic honeycomb structure. More than 330,000 individual cells make up the honeycomb, and Textron technicians — using a special dispensing gun — filled the cells by hand with a material called Avcoat. The Avcoat insulation is supposed to ablate away during the Orion spacecraft’s re-entry, protecting the underlying structure from searing temperatures. The Apollo moon capsule used the same type of manually-applied material for its heat shield, and it worked so well Lockheed Martin and NASA decided to dust off the design.

Engineers scaled up the heat shield for the Orion crew capsule, which is about four feet wider at its base than the Apollo command module. “That’s what worked for Apollo, and that’s what we’ll work with for this mission,” Bray said, referring to the EFT-1 launch in December.

But a review of the heat shield on the Orion spacecraft set for launch Dec. 4 revealed the Avcoat was slightly more uneven than expected, according to Jim Bray, crew module director at Lockheed Martin, Orion’s prime contractor.

It also appears that it is too expensive to build the shield by hand, as it was done during Apollo. Instead, they intend to build future heat shields as single blocks assembled not by hand but by machine.

This is another example of why SLS/Orion is an incredible money black hole. What is the point of next month’s test flight of the heat shield if the shield they are testing is not going to be used on future flights?

Meanwhile, the press (apparently ignorant and uninformed about this subject and brainwashed by a NASA Orion press event) is filled with numerous stories claiming that this test flight is NASA’s first step to getting to Mars. What hogwash.

I especially like this quote from the space.com article:

On Dec. 4, NASA officials are expected to launch the Orion spacecraft on its first test flight, putting the capsule through its paces in space before it splashes down in the Pacific Ocean. The goal of the flight is to see how some key Orion systems — like its huge heat shield and parachutes — work before launching humans into deep space sometime in the future. [emphasis mine]

Yet, most of the heat shield test data obtained by this test flight will be worthless and inapplicable to future Orion capsules. In other words, this test flight is, as I said, hogwash, a public relations stunt to sell Orion to Congress and to uneducated reporters. It is also an enormous waste of taxpayer money and the limited resources NASA has.



  • Pzatchok

    You would think they would have planned on using the heat tiles off of the shuttle.

    On Orion they would be protected inside the assembly until the time of re-entry. Thus much safer.

  • Mike

    Orion is using shuttle-style (mildly upgraded) tiles for the sides of the capsule. This is a good test of the new design and config for them.

    The argument in favor of this version of the heat shield still being a valuable test is that the ablative mix being used for the honeycomb design is the same they’d intend to pre-build in blocks for installation. It’s sort of like if they’d flown a Shuttle flight with hand-done small tiles, then decided that larger tiles would work better, and adjusted the design to improve the operability. This does not mean you can’t learn actual useful technical knowledge from the flight, as you’re still finding out if the shape and the material itself perform as expected. I’d note that my hypothetical is somewhat less than one, as some of the layout and design of the Shuttle underside did indeed evolve over the course of the program. Some manual processes were indeed replaced with manufactured designs. This didn’t mean earlier flights weren’t useful.

    While I’m somewhat biased by working directly on the program, I think it is absolutely fair to be critical about how we’re spending your tax dollars. Only way we’ll do better is by listening to critiques and doing our best to learn from them and find ways we can improve.

    I just think in this particular case you are going a couple steps farther down the “useless experience” trail than is truly fair. Fine to argue it’s a capsule to nowhere, but if we do use it, this test flight does give us some actual engineering data to help with subsequent flights.

    My two cents at least. Appreciate your thoughts, critical and otherwise!

  • Your points are well taken. I appreciate them.

    Though I have always recognized that some good engineering data will come from this Orion test flight, the overall dishonesty surrounding the SLS/Orion program just infuriates me beyond words. For the amount of money we are spending on this rocket and capsule, neither of which will ever accomplish any of their stated interplanetary goals, we could have fully funded three privately built manned spaceships, given the unmanned planetary program more money than it knows what to do with, and still reduced NASA’s budget by a couple of billion, thereby helping to reduce our debt.

    Instead, we get this Potemkin village of a rocket. It makes me sick.

  • Pzatchok

    Since they are using thin, light heat tiles on the outside of the capsule, is that why they have an ejectable shell on it for lift off?

    Something Apollo never seemed to need.

  • Mike

    I have some concerns and uncertainties about the SLS path. I can see the benefits of having a super heavy launcher, but a low flight right and high cost per flight are significant downsides for a wide range of reasons. In a way I have tended to see it as trying to keep open the possibility of recovering an Apollo-era style program, but one which would need larger than current budgets to be functional. Plenty of other things I dislike about various aspects of the architecture and design, but it seems a set path that DC wants us to pursue, so I think it’s the path we’ll keep working on for the foreseeable future.

    I’d honestly be okay with a budget reduction if the rest of the federal budget took similar or reasonably larger diets too. I’m honestly tired of science and engineering investments getting crunched while other sections of the federal budget continue to expand with surprisingly efficiency and speed. It perhaps is one thing Government is actually good at. Rapidly bloating budgets. Not that such could be called a good feature, unless your interest is in political power and ability for kickbacks and payoffs. Bit out of my field of expertise though. I’m not a fan of an ever growing national debt. Just don’t consider NASA to be a statistically significant cause.

    I do hope that if we stick with the SLS we at least use it for some useful projects. Likewise, if Orion survives the coming of the COTS vehicles I hope we’ll use it for useful projects that help expand our ability to live and work in deep space. Not going to argue it’s the most theoretically cost effective path, but I’m trying to be pragmatic. If it’s the program we’re tasked with, I hope we can at least make productive use of it.

  • Mike

    If I understand right there actually was a LAS ‘cover’ of some sort over the top of the command module on the Apollo flights. Best I could scrounge up with a little google searching was: http://www.apollosaturn.com/boost.htm

    I don’t know how solid or how heavy this was, but I recall reading something about having a pair of hatches while sitting on the launch pad, not just the CSM hatch. I think this got improved following Apollo I in some fashion as well, but I’m unclear on the details.

  • Edward

    The next time you watch the movie “Apollo 13,” look for the sun to shine through a window into the CM just as the escape tower jettisons. That is the Cover coming off with the tower.

  • Pzatchok

    The Apollo shield was small (just covering the nose) compared to Orions.


    Add this disposable shield to all the ones going to be installed on the service module and you have a huge amount of wasted weight and space junk to worry about.

    Adding these on when the shuttle didn’t need any ( or at least didn’t use any) does not make sense.
    The excuse that they will cut down on vibration and noise is a little thin since they could have just made the Orion capsule that same shape and lived with the noise.

Leave a Reply

Your email address will not be published. Required fields are marked *