FICTION
While on the subject of future spaceplanes let us have a look at how these were (and still are) depicted in fiction. The existence of spaceplanes as an efficient means of transportation between Earth and space is generally taken for granted in science fiction, much like airliners are used in the real world. Apart from ideal aircraft-like operations, one thing that most of the spaceplanes in science fiction books, movies and television series appear to have in common is an amazingly efficient propulsion system because most of the volume is available for passengers and cargo rather than being taken up by bulky propellant tanks.
Take for instance the Orion III ‘Pan Am Space Clipper’ of the famous movie 2001, A Space Odyssey of 1968. We are shown a spaceplane that operates much like an airliner, even with stewardesses. No take-off is shown in the movie but it appears that the Orion is a single stage vehicle with double-delta wings (similar to those of the Space Shuttle, which had not yet been designed when the movie was produced). Windows cover only a short stretch of the middle of the fuselage, which makes sense for a spaceplane requiring large volumes of propellant. Still, as a relatively small single-stage-to-orbit spaceplane (judging from the size of the windows) 200Гs Orion must have fantastically efficient engines; jet engines, if the series of holes that can be seen on the leading edges of the plane’s wings and in front of the engine module are air intakes. However, having intakes on the wing leading edges would be rather poor engineering: tapping off the air before it has a chance to flow over the wings would seriously reduce lift. Nevertheless, Orion is probably the most believable spaceplane ever depicted in any block-buster movie.
The most famous space fighters of the movies, the Star Wars’ X-wing and Battle Galactica’s Viper, have wings and very apparent air intakes but spend most of their time in the vacuum of space. Even so, they seem to require only very small amounts of propellant as there are no large tanks to be seen. This does not seem to make sense: if you can fly and maneuver in space for hours without any external airflow, why bother with air intakes and wings for the brief periods in an oxygen-rich atmosphere? Moreover, these vehicles seem to maneuver in space as if they were flying through air, banking into nice round turns, flying in loops etc. In space there are of course no aerodynamic lift and drag forces, making such maneuvers only possible with the help of a serious set of reaction control thrusters which aren’t apparent in these fictional designs. Moreover, such airplane-like actions are rather useless in space (but not in a movie, as it certainly looks more exciting than real orbital mechanics).
Fireball XL5, a spaceplane shown in the British 1962-1963 television series of the same name also lacks apparent propellant tank volume, but according to the series it is powered by a “nutomic reactor” that enables it to have a range of many lightyears. Although the Fireball is a fictional vehicle without any regard for the limitations of real spaceflight, it is interesting to note that it takes off using a rocket powered sled and a mile-long launch rail that culminates in a 40 degree “sky ramp”, whereupon the spacecraft uses its own propulsion to ascend into space; very similar to the takeoff mode of Sanger’s Silverbird.
In reality, even although serious work on orbital spaceplanes has been underway since before the Second World War, they still only fly in the realms of fiction. Like most of the hardware depicted in 2001, A Space Odyssey, nothing like an Orion III was available in the real year 2001; nor in 2011 for that matter. Only the videophone used the movie is actually better in today’s reality. In general, science fiction often overlooks the complexity of spaceplane transportation, and especially the limitations of propulsion technology. Of course, with engines working on fantasy and built out of unobtainium, anything is possible. What the spaceplanes of the movies do show us, however, is the ultimate goal of the real-world launch business: airline-like flights into space.