X-15 on the tarmac
In this slideshow, we'll take a look at the X-15 rocket plane, which first flew 50 years ago this week and which NASA calls "the most successful research aircraft ever built." This image shows the X-15-1 aircraft in 1958, at which point the XLR-99 rocket engine intended for it was not ready, so it was fitted with a pair of older XLR-11 engines, like the one used in the earlier X-1.
June 12, 2009 8:54 AM PDT
Photo by: NASA
| Caption by: Jonathan Skillings
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