Editing Unobtainium (section)

== Engineering origin ==
Since the late 1950s, aerospace engineers have used the term "unobtainium" when referring to unusual or costly materials, or when theoretically considering a material perfect for their needs in all respects, except that it does not exist.

{{blockquote|Unobtainium, n. A substance having the exact high test properties required for a piece of hardware or other item of use, but not obtainable either because it theoretically cannot exist or because technology is insufficiently advanced to produce it. Humorous or ironical. |source=Listed in "Interim Glossary, Aero-Space Terms," as compiled by Woodford Heflin and published in February 1958 by the Air University of the US Air Force.<ref name="Langley">Since at least the 1950s: [https://history.nasa.gov/SP-4305/sp4305.htm Hansen, James R. (1987) "Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917–1958". The NASA History Series, sp-4305.] Chapter 12, recounting an October 1957 meeting, mentions the problems caused by "the lack of a superior high-temperature material (which the Langley structures people dubbed 'unobtainium')" This paragraph in turn cites Becker, John V. "[https://books.google.com/books?id=nM9KrgEACAAJ&q=unobtainium The Development of Winged Reentry Vehicles, 1952–1963]", unpublished, dated 23 May 1983.</ref>}}

By the 1990s, the term was in wide use, even in formal engineering papers such as "Towards unobtainium <nowiki>[</nowiki>new composite materials for space applications<nowiki>]</nowiki>."<ref>{{cite journal |url=http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=TRD&recid=200114009286MT&recid=A9116974AH&q=towards+unobtainium&uid=788302480&setcookie=yes |archive-date=2009-04-24 |archive-url=https://web.archive.org/web/20090424223613/http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=TRD&recid=200114009286MT&recid=A9116974AH&q=towards+unobtainium&uid=788302480&setcookie=yes |title=Towards unobtainium <nowiki>[</nowiki>new composite materials for space applications<nowiki>]</nowiki> |last=Misra |first=Mohan <!-- see www.itnes.com/misra.html-->|journal=Aerospace Composites and Materials |volume=2 |pages=29–32 |date=Nov–Dec 1990 }}</ref><ref>{{cite conference |title=Parametric cost analysis: a design function |last=Dean |first=Edwin B. |book-title=American Association of Cost Engineers 33rd Annual Meeting |volume=25 |pages=28 |date=1989
 |citeseerx = 10.1.1.45.5018}}</ref>

The term may well have been coined in the aerospace industry to refer to materials capable of withstanding the extreme temperatures expected in [[atmospheric reentry|re-entry]].<ref name="Langley" /> [[Aerospace engineering|Aerospace engineers]] are frequently tempted to design aircraft which require parts with strength or resilience beyond that of currently available materials.

Later, unobtainium became an engineering term for practical materials that really exist, but are difficult to get.<ref>{{cite web |url=http://www.metalsuppliersonline.com/research/Charts/periodic/113Unobtainium.asp |title=Unobtainium |publisher=Metal Suppliers Online |access-date=2010-06-04 |quote=We can loosely define it as any metal that is specified by Engineering and unavailable to Purchasing }}</ref> For example, during the development of the [[SR-71 Blackbird]] spy plane, [[Lockheed Corporation|Lockheed]] engineers at the "[[Skunk Works]]" under [[Kelly Johnson (engineer)|Clarence "Kelly" Johnson]] used unobtainium to refer to [[titanium]]. Titanium allowed a higher strength-to-weight ratio at the high temperatures the Blackbird would reach, but its availability was restricted because the [[Soviet Union]] controlled its supply.  This created a problem for the U.S. during the [[Cold War]] because the Blackbird required huge amounts of titanium; subsequent U.S. military aircraft such as the [[B-1 Lancer]], [[F-15 Eagle]], [[F/A-18 Hornet]], and [[F-22 Raptor]] required relatively large amounts of it as well.