On spaceflight (or, the mun is a huge nerd)
There are two basic levels of Space Mods for cybertronians: Space Rated and Space Optimised.
Space Rated is what we see on Starscream in the show - he clearly is able to manuver in vaccuum with no ill effects but there is no indication of radiators on his frame (as well, he would probably find them unsightly). Subsurface radiators in the wings hooked into the atmospheric cooling system already in place,as well as energon burning rcs thrusters mounted strategic places on both root and alt modes. This is suitable for a while, but has endurance limits, as it draws against a bot’s main energon reserve, but requires only a minimum of extra systems. However, it is limited in orbital endurance by heat buildup in the systems, and safe maneuver time by energon supply.
Space Optimised is a much more involved mod package, including a large reaction mass tank, and the plumbing to all rcs thrusters and the main engines, as well as beys for dedicated folding solar panels and radiator arrays.
A Space Rated bot would be able to perform EVA without assistance, but may not be able to reach orbit alone. It is not unknown however, and is a very freeing capability, not being limited by needing a dedicated ascent vehicle.
A Space Optimised bot, however, is not limited in orbital endurance except by reaction mass (dV for my fellow space nerds). The energon powered thrusters have a much higher mass efficiency (Isp) than energon burning, with the added benefit of not depleting frame energon.
something for your perusal