why are the americans obsessed with BIG rockets?

[womblemaster]

BBC News - Nasa unveils Space Launch System vision

surely its more efficient to use a `drop ship` type craft like the new virgin space ships. ie a carrier ship that returns to earth, that drops a smaller vessel near orbit.

isnt the `blast off from earth` type rocket 50yearold technology?

am i missing something or is it just american ego to require these big launch rockets?

[Superewza]

Getting into orbit isn't simply a matter of getting up high enough, it's to do with how fast you have to go - you have to go so fast that you miss the Earth when you fall. The Virgin space craft aren't nearly capable of that, and are only viable because they use existing technology (in in-atmosphere flight) to provide 'relatively' cheap sub-orbital trips to space. Which aren't much use in scientific terms.

Larger rockets means larger payloads which means the potential for what you could do with it is much higher. We could have launched the entire ISS on something like three or four Saturn Vs. It also means you can have (manned) spacecraft with their own engines which the launch vehicle would drop into orbit, and from they they could under their own power travel beyond LEO, to the moon or on interplanetary missions - something that smaller rockets don't have the capability of doing, without designing a modular craft that would assemble in orbit and then go off, requiring far more launches for any particular task.

[jabberwocky]

like said above, to get get stuff into space you need a blumming big rocket, the shuttle may have been reusable but it still needed a bloddy big rocket to get it into space. this new rocket has the capacity of 4 or 5 shuttles. the virgin thing only just gets to space, ish, sort of, not really.

[Earl]

I wonder why Rockets are not launched from higher altitudes?

Pondering on this, I can imagine that the costs of building, getting to and maintaining a High altitude Space Port probably out-way any benefits (if there are any)

[Breakintheclouds]

It was this sort of issue that Arthur C Clarke spent a lot of time thinking about. Read The Fountains of Paradise to see his space elevator solution...

[FraserClarke]

I wonder why Rockets are not launched from higher altitudes?

Highest point on the Earth is only 8km, only about 2% of the way to the ISS. So in altitude terms it doesn't make much difference. Maybe a slight gain from starting in a thinner atmosphere.

Main thing is to be as close to the Equator as possible, so that you get more 'slingshot' on launch.

[Superewza]

Highest point on the Earth is only 8km, only about 2% of the way to the ISS. So in altitude terms it doesn't make much difference. Maybe a slight gain from starting in a thinner atmosphere.

Main thing is to be as close to the Equator as possible, so that you get more 'slingshot' on launch.

Assuming that you're launching into an orbit in the same direction of travel as the rotation of the Earth, polar and retrograde orbits don't get such a boost, and could benefit from launch sites being as far away from the equator as possible.

[Teal Rain]

There's an excellent book called "Halfway to Anywhere" - written about the time SSTO was the in thing or Robert Zubrin's "The Case for Mars" - both are a good source of info.

M

[Superewza]

Ha, my sig on another forum is "As Robert Heinlein noted, once one gets into Earth orbit, you are "halfway to anywhere."" That's just a quote i pulled from Atomic Rockets though, which is a really great website however you cut it. I'll be sure to put that book on my list though!

Atomic Rockets