from one engineer to another, those issues suck.
You should really delve far deeper into your topics instead of being incredibly broad.
let's take your first one, alternative fuels...
fuels for what? Factory work, construction, moulding, deformation, electical power, commercial aircraft, combat aircraft, consumer goods, manufacturing goods, unmanned equipment.
That's all of the top of head
another problem with your titles are that they seem very cliche. Go and do some research into fields and see what the issues they are facing are now so your work is up to date and relevant rather than back dated stuff that has reached the medium of television and everyone from your gran has an unrealistic opinion about.
the same goes for space exploration
are you talking about manned, unmaned, developments of optical telescropy, shielding of vehicles from meteorite bombardment, gamma rays, extreme temperatures as well as all the psychological issues of people in space and dealing with boredom, reproduction, sustainable food sources etc.
