Space would be fine, you could then also change the jammer button to Q or shift so it is easier to press with the space bar. Another option is to have "z" as jump and "x" as jammer with the arrow keys instead of wasd. Hope this helps :)
Actually the control you mention is all there in the game.... (except shift) you can use both x and space to jump. you can use both Q and Z to use jammer. you can use both arrow and WASD to move.
