I came across your account of your trip to White Sands in 1980:

We completed our work by the second day, and we had several spare hours before heading for the airport — so off we went to see the much-fabled "Northrup Strip" (a careless misspelling of the aviation firm, Northrop, that had built and used it decades before).

A dusty corner of space shuttle history (MSNBC)

That caught my eye because I could've sworn that the school I almost attended in 1972 was the Northrup Institute of Technology in LA, and so I got curious about the discrepancy.

The Web search was a headache: Apparently Google considers "Northrup" to be an alternate spelling of "Northrop", and indeed many genealogies showed an entry for "Northrop/Northrup". It turned up all the Northrop-Grumman Web sites, but none of them contained the variant spelling or explained the confusion.

As far as the landing strip goes, I finally found a history piece at White Sands Missile Range that explained it:

Northrup Strip History

Northrup Strip, in the salt/gypsum area called Alkali Flats, became part of WSMR in 1952. The strip is centered in a 100 square-mile area about 45 miles due north of WSMR Headquarters. In the late 1940s Northrop Aviation Corporation used the natural landing area for target drone projects. The strip was unofficially called "Northrop Strip" through association with the contractor. An early press release $Äed a typographical error, misspelling Northrop as "Northrup." The error was reproduced in subsequent releases, and later signs, route markers and official Army maps carried the name Northrup Strip, making it quasi official.

Northrup actually has two strips, crossing like an "X." The original and primary strip runs almost due north and south, while the secondary strip (added for shuttle program use) runs northeast/southwest. These hard packed gypsum strips, each 35,000 feet long, provide what the shuttle needed in the early landings -- a long, forgiving runway. Later flights have terminated on the shorter, concrete runways at Kennedy and Edwards. Northrup is virtually unobstructed, can be seen from space and is blessed with excellent weather 90 percent of the time.

I suspect that the reason that the typo stuck (on top of bureaucratic inertia) is because of the geneaological association between the two spellings, which would've reinforced the alternate spelling and sown confusion among anybody trying to figure it out.

So there you go--the tiniest of historical nits satisfactorily picked.