Part of the show Science Q&A Show
Connor in Tillingham asked:
Could you launch satellites and perhaps many small capsules from airships to save on all that fuel getting it off the ground?
There's still a problem with this, which is that you have to achieve what's called orbital velocity. You could get very close to space in a big airship, but if you let go you would still fall. In order to be in orbit you have to be moving fast enough that gravity is just strong enough to hold you in a circular orbit. This is about 27 000km/hr so whilst a large balloon would help you get into space, it wouldn't help with the difficult bit of moving fast enough to stay there.
Saying that some american companies are suggesting it as a way of getting into space, because if you can get up above the atmosphere, you don't need to fight air friction so a large rocket to get into space in not needed, you can gently gain height using a much smaller one for much longer.