I'm working out a new hypothesis to put a load into orbit for the ISS.
But I can not get a certain answer from the following problem: with the current launch systems I assume that at least 9/10 of the total mass of a rocket (+orbiter + load included) is lost to put in orbit at about 7.66 km / sec the aircraft with the load. It's true?
You can work the rocket equation Jim linked backwards to give the mass ratio achievable with some assumptions about specific impulse. Note also that you don't just need the final 7.6 km/s of lateral orbital velocity but also vertical speed to get to height and account for losses, meaning that typical delta-v for orbital launch is more like 9.6-10 km/s.
Welcome to the world of rocketry ! Yep, that's pretty right. 9 km/s, average, to get into a very low Earth orbit.
More or less 7.7 km/s plus the gravity losses and the drag losses. It hurts.
And yes, 92% of a SSTO, as standing on the launch pad, is pure propellants - most of it LOX with a bit of fuel.
Single Stage To Orbit is hard.
Staging makes things easier. Drop dead mass.
Earth is a massive rocky planet at the bottom of a deep gravity well, with a thick atmosphere on top of that.
But once we get out of that deep well and start operating at merely ground level, and not coming back down to the bottom of the well all the time, the technology we made to climb out of it will be quite capable. SSTO on Mars or the Moon doesn’t require staging, for example, just a decent-performing rocket.
Thank you all
I will try to repay you within about 1 month and a half offering a resolutive hypothesis .... you just have to be patient because I mainly fight another war
www.asps.it/versomarte.htm :-)