Getting into orbit from a gravity well is difficult. Fully 69% of the liftoff mass of the Space Shuttle was the semi-disposable rocket boosters used just for achieving orbit. Yet ships in science fiction routinely do orbit in a single stage (without any visible propellant tanks, which could very well be its own trope—sometimes even with propulsion systems like ion engines, that basically don't work in atmosphere
Relatedly, not only do ships in science fiction get off planets easily, the same ships are used for achieving orbit as for orbit-to-orbit interplanetary flight. This is unlikely in the extreme; people are more likely to use dedicated shuttle-like entry vehicles, or else methods like space elevators, to get to orbit, and then, once in space, board dedicated system rockets for orbit-to-orbit. Especially noticeable when ships that can do this—what is, again, basically impossible—are described as "pieces of junk" or similar, often because they belong to the tramp steamship...uh, spaceship...captain
Relevant external link here
. Probably a subtrope of Space Does Not Work That Way
and Artistic License – Physics
, as well as involving Sci-Fi Writers Have No Sense of Scale
, namely regarding the amounts of energy involved. Sometimes worked around by Phlebotinum
- The Serenity can do SSTO and orbit-to-orbit, yet is routinely called a clunker and a piece of junk.
- Ditto the Millennium Falcon.
- Both averted and played straight by the Halo franchise. Military ships seem to have no problem landing and taking off again, at least on the eponymous Big Dumb Objects, but most humans and their cargo seem to get to planetary orbit by means of space elevators or, in the case of the Sabers in Reach, by means of Two-Stage to Orbit rocket boosters.