I was a bit surprised to learn that the Buran used heat tiles looking very similar to that of the Space Shuttle. Considering its potential for military application, and the cold war period in which both the US Space Shuttle and Russian Buran were developed, was any of the heat tile technology ever classified as state secret? If so, how did the Russian space program end up with something so similar? Was any/all of the technology patented (which would account for public disclosure and availability of the necessary information to reproduce it)?

  • $\begingroup$ What potential for military application? ICBM reentry vehicles have to use thick ablative heatshields - SS/Buran-like tiles would burn up under those sorts of thermal loads, and and turnaround time isn't a factor for something that's only ever going to be used once. $\endgroup$
    – Vikki
    Jul 21, 2019 at 0:44

2 Answers 2


Apparently the technology wasn't even patented.

"Lockheed refused to file a patent, saying there was no market for it," Forsberg said. "It was put on the shelf and his research stopped for two years. Then interest from the shuttle program revived it."

As described in Heppenheimer's Development of the Space Shuttle, 1972-1981 Chapter 6, Thermal Protection, manufacture of the tiles is fairly simple. (I am sure the devil is in the details though).

A slurry of silica fibers of 1.5 micron diameter mixed with a collodial silica binder is pressed into rectangular molds, dried in a microwave oven, then baked in kilns. The resulting blocks were then shaped and coated with a reaction-cured glass coating.

(summarized by me)

The manufacture was simple enough that after Orbiter production ceased, replacement tiles were made in a small tile shop at Kennedy Space Center.

enter image description here

Picture from Wings in Orbit

Ancedotally, I don't remember any aspect of tile technology being treated as sensitive when I worked in the program. Detailed information is available in the Press Kit which was contemporary with the first launch.


  • 2
    $\begingroup$ re: "not even patented" - a patent requires you to disclose what you're patenting, so a patent would have contained a detailed description of how to produce these tiles. Patenting is not something you do for classified processes. $\endgroup$
    – Hobbes
    Mar 4, 2018 at 14:44
  • 1
    $\begingroup$ I know, I included the quote just because I thought it was interesting that LockMart thought it was worthless tech. $\endgroup$ Mar 4, 2018 at 14:51
  • 1
    $\begingroup$ Not filing a patent doesn't necessarily mean they thought it was useless. Patents have a ticking clock -- they require disclosure, and they expire. If you don't make any money before the patent expires, then you just gave away your tech for free. Putting it on the shelf allows them to keep it as a trade secret, until the time is right. You don't file for a patent on something like this unless a) you think you can use it to make money before it expires, and b) you are worried someone else might patent it first. $\endgroup$
    – Tristan
    Mar 5, 2018 at 17:35
  • 1
    $\begingroup$ The quote says they thought there was no market for it. $\endgroup$ Mar 5, 2018 at 18:19
  • $\begingroup$ That sounds rather similar to the fibrous refractory insulation that is used in most recently-built industrial furnaces, except that this insulation is probably denser and definitely alumina-silica rather than just silica. $\endgroup$
    – ikrase
    Mar 1, 2020 at 3:43

Even though it occasionally launched military satellites from the Shuttle, NASA is explicitly civilian, created during the Cold War to demonstrate to the world our peaceful use of space for all mankind, etc, etc. Thus, they don't develop State Secrets.

(Military rockets that launch from Cape Canaveral launch from Cape Canaveral Air Force Station, which is next door to Kennedy Space Center.)

From the law authorizing NASA:


§ 20101. Short title This chapter may be cited as the ‘‘National Aeronautics and
Space Act’’

§ 20102. Congressional declaration of policy and purpose (a) DEVOTION OF SPACE ACTIVITIES TO PEACEFUL PURPOSES FOR BENEFIT OF ALL HUMANKIND.— Congress declares that it is the policy of the United States that activities in space should be devoted to peaceful purposes for the benefit of all humankind.

(b) AERONAUTICAL AND SPACE ACTIVITIES FOR WELFARE AND SECURITY OF UNITED STATES.— Congress declares that the general welfare and security of the United States require that adequate provision be made for aeronautical and space activities. Congress further declares that such activities shall be the responsibility of, and shall be directed by, a civilian agency exercising control over aeronautical and space activities sponsored by the United States, except that activities peculiar to or primarily associated with the development of weapons systems, military operations, or the defense of the United States (including the research and development necessary to make effective provision for the defense of the United States) shall be the responsibility of, and shall be directed by, the Department of Defense; and that determination as to which agency has responsibility for and direction of any such activity shall be made by the President.

  • $\begingroup$ Various computer technologies (encryption being one in particular) have been on embargo lists because of their potential for military application, even though its critical to civilian use like securing internet sites for purposes like online banking. Technology related to vehicle re-entry could be be used for nuclear warheads. $\endgroup$
    – Anthony X
    Mar 3, 2018 at 23:20
  • $\begingroup$ @AnthonyX was encryption developed by NASA? No. $\endgroup$
    – RonJohn
    Mar 3, 2018 at 23:37
  • $\begingroup$ @AnthonyX quite successful heat shielding for nuclear warheads were developed by both the US and Sovs loooong before the 1970s. $\endgroup$
    – RonJohn
    Mar 3, 2018 at 23:39
  • $\begingroup$ Much of the information relating to those DOD payloads on the shuttle was classified at the time, including launch times, azimuths, etc, which information was certainly developed by NASA flight design based on customer requirements. As were the flight plans, crew training plans, and other mission related documentation. Some of that information is still classified. $\endgroup$ Mar 3, 2018 at 23:58
  • $\begingroup$ @OrganicMarble that has nothing to do with whether or not NASA is a civilian agency? $\endgroup$
    – RonJohn
    Mar 4, 2018 at 4:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.