In early 1960 the US Air Force offered a development contract to build an "aerospaceplane" with a crew of three that could take off from any runway and fly directly into orbit and return. They wanted the design to be in operation in 1970 for a total development cost of only $5 billion. Several corporations submitted proposals, including Douglas with its 1962 Manned Aerodynamic Reusable Spaceship (Model 2235).
Needless to say, none of these spaceplanes were ever built. The technological challenges soon revealed that the project was too ambitious. As a writer with "Aerospace Projects Review" wrote:
"Clearly, someone at Douglas had watched "When Worlds Collide" a few too many times. This was designed not as a true SSTO, but as a twin-ship formation... one carrying payload, the other carrying extra propellant. They would meet up at a speed of Mach 6.5, and the mission aircraft would be refueled. That would, undoubtedly, be entertaining."
Here is a 2009 image of what it would have looked like in operation.
I have a vintage photocopy, stamped "UNCLASSIFIED", of Douglas' Manned Aerodynamic Reusable Spaceship proposal. It's hundreds of pages long (divided into 14 sections I'd have to add up to give an exact page count; suffice it to say that it's two inches thick) and full of diagrams, charts, and other details. It has two holes punched at the left and is bound by two metal rings.
Very interesting for someone interested in spacecraft design, and I can't find another copy of it, or even a mention of this specific document, anywhere online.
$30, plus another $5 for domestic shipping in a box.
(The "When Worlds Collide" reference pertains to the space ark built as a lifeboat in the 1951 movie, as planetwide disaster approaches. You can see at about 0:40 and 1:20 in the trailer (or in this photo of a model you can still buy today) that Douglas' design really did resemble it):
(By the way, if you are a character in a sci-fi disaster movie, do NOT say with a smug smile "I think all of you scientists are crackpots. Nothing is going to happen!" Just do NOT say it.)