Neil Armstrong

mudcow007

if space shuttles have to use so much fuel to break through the atmosphere an cost so much, why not use helium to lift up to a certain altitude then light boosters an away you go

if a $200 helium balloon can do it , why cant Nasa

Kieran_Burns

mudcow007 wrote:

if space shuttles have to use so much fuel to break through the atmosphere an cost so much, why not use helium to lift up to a certain altitude then light boosters an away you go

if a $200 helium balloon can do it , why cant Nasa

Yeah and while your at it why should I pay hundreds of pounds when my 99 quid bike from tesco is as good as your fancy crabon racer thing and those tires must be really hard and my suspension makes it dead cumfortable not like yours and my bikes got 27 gears and why has yours only got 1

Daz555

mudcow007 wrote:

if space shuttles have to use so much fuel to break through the atmosphere an cost so much, why not use helium to lift up to a certain altitude then light boosters an away you go

if a $200 helium balloon can do it , why cant Nasa

The space shuttle alone weighs in at over 100,000kg.

BIG balloon and helium is both rare and expensive.

mudcow007

Daz555 wrote:

The space shuttle alone weighs in at over 100,000kg.

BIG balloon and helium is both rare and expensive.

lots of balloons?

how much do the rocket motors cost to run?

tgotb

mudcow007 wrote:

Daz555 wrote:

The space shuttle alone weighs in at over 100,000kg.

BIG balloon and helium is both rare and expensive.

lots of balloons?

how much do the rocket motors cost to run?

OK, just did the sums for this on the back of an envelope. The difficult/energy-intensive part of getting to low earth orbit (LEO) isn't getting the altitude, it's getting up to orbital velocity. Around 90% of the energy imparted to an object in LEO is kinetic, rather than potential.

Minimum altitude for LEO is around 200km. Even if you could get a balloon up that high (which you can't), your rocket still needs to be able to provide 90% of the energy of an Earth-launched one. If you take the marginally more realistic balloon altitude of 100km, that rises to 95%. So you trade the relative simplicity of launching from solid ground, in order to make your rocket ~5% smaller. Very unlikely to be worthwhile.

Quick bit of Apollo trivia: The Saturn 5 trajectory started off relatively vertical, to get the rocket out of the thickest part of the atmosphere before it was going fast enough to cause aerodynamic loading issues. This gave it too much vertical speed for the target LEO, and so for a subsequent part of the trajectory it was actually pointing slightly downward!

Greg T

ahhhhhhh . . . .

So it's not getting it to altitude - it's getting it to orbit and then getting it going round fast enough to stop getting it pulled down again that takes the energy . . .

JamesB5446

milleman wrote:

Very poignant speech, thankfully not needed.

I too consider the Apollo mission to be mankinds greatest achievement, surely the future for our kind is in space-we are simply using up this planets resources at too fast a rate to survive here in the long term

Brilliant plan!

Or, this might sound silly, we could just focus on wasting our resources less.

mudcow007

TGOTB wrote:

mudcow007 wrote:

Daz555 wrote:

The space shuttle alone weighs in at over 100,000kg.

BIG balloon and helium is both rare and expensive.

lots of balloons?

how much do the rocket motors cost to run?

Lots of stuff....

nice, well it was just an idea

there was a plan awhile ago to use a weather balloon to roughly 25km up, launch a uav drone and camera. when the balloon burst the plane would glide down (hopefully has enough lift to sustain flight) an flies back home using predetermined route via gps

i think the team struggled with gps reception so high

interesting project though

Kieran_Burns

mudcow007 wrote:

TGOTB wrote:

mudcow007 wrote:

Daz555 wrote:

The space shuttle alone weighs in at over 100,000kg.

BIG balloon and helium is both rare and expensive.

lots of balloons?

how much do the rocket motors cost to run?

Lots of stuff....

nice, well it was just an idea

there was a plan awhile ago to use a weather balloon to roughly 25km up, launch a uav drone and camera. when the balloon burst the plane would glide down (hopefully has enough lift to sustain flight) an flies back home using predetermined route via gps

i think the team struggled with gps reception so high

interesting project though

Geostationary orbit is something like 22,500 miles up - I would think a piffling 25k would not be a problem.

rick_chasey

TGOTB wrote:

Quick bit of Apollo trivia: The Saturn 5 trajectory started off relatively vertical, to get the rocket out of the thickest part of the atmosphere before it was going fast enough to cause aerodynamic loading issues. This gave it too much vertical speed for the target LEO, and so for a subsequent part of the trajectory it was actually pointing slightly downward!

Good quality trivia that. 8/10.