Algodoo

engines run out of fuel, and activated by pressing "w", and parachutes don't work yet, just for decoration, fuel tanks also don't work (because scripting is hard), so liquid fuel engines just don't use fuel at all. decouplers are activated by pressing "d".
If you want to make a spacecraft, glue the parts together
added engine exhaust, removed part impact (it caused too much bugs)
comes with free starter rocket!