The company's Pegasus XL rocket was flown to a launch altitude of about 39, 000 feet by a specially configured L-1011 "Stargazer" jetliner taking off from the Kwajalein Atoll in the Marshall Islands in the Pacific, near the equator about halfway between Hawaii and Australia.

WSJ: NASA NuStar Telescope to Hunt for Black Holes

There are numerous types of spacecraft and missions that can be configured in various mix-and-match combinations, and many of which never launched off the drawing boards.

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