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jhwegener
2005-Feb-27, 02:16 PM
For the sake of pure curiosity:Has anyone ever seriously considered balloons for space travel? If Big and light enough (containing fewer atoms pr. volume)they could in theory be used for interplanetary travels?
On the other hand: some planets (and moons?) have heavier atmospheres than our (Venus, Jupiter, Saturn, Uranus, Neptune). So heavier, better protected Balloons or "Airships" Could eventually be used?

piersdad
2005-Feb-27, 04:49 PM
baloons will get you to the edge of space but from there you have to pick up speed to 17000 plus mph or the earths gravity will suck you back.
then you have to sligshot from earths gravity to pass the moon and a further speed up to get out of the suns gravity.
so yes and no the balloon will get you close an wont get past the atmosphere as it has to float on something.
a balloon will act as a platform so that a rocket will be able to take off with out too much air to stop it
and for space trael you need speed and lots of it

zrice03
2005-Feb-28, 05:46 AM
Hey, there's actually an organization that is attempting something like this.

http://www.jpaerospace.com/

I actually don't know if this could work (I think a balloon like that would create too much drag), but I certainly encourage them to try.

piersdad
2005-Feb-28, 07:19 AM
actually don't know if this could work (I think a balloon like that would create too much drag), but I certainly encourage them to try.

you bet and if they get above 10,000 feet the ballons gass will expand to twice its volume and they ether have to release it of have a bigger envelope.
most of the space faring ballons are about 1/4 full as they take off and once near space are fully inflated.

or to put it another way i certainly would not go up in their balloon above 3,000 feet

jhwegener
2005-Feb-28, 08:45 AM
Still, interplanetary(interstellar, intergalactic space for that) space is not exactly vacuum. There is always some atoms or even molecules - that is some mass. So in theory it should be possible to make a "lighter than space" device. Which - still in theory - would float "upward" (away from sun?)
Anyway some planets have rather "heavy" atmospheres. So balloons, planes, etcetera might be used there, even heavier than on earth? (of course there may be some problems with materials, for instance in acidic´or very cold or hot conditions. But are they unsolvable? There is also the question "is it worth it". But that´s allways a question with expensive space programs).

piersdad
2005-Feb-28, 06:55 PM
once in space you come under the effect of the earths gravity-- the moons gravity -- the suns gravity.

Its like a a roller coaster ride.
to get away from ther earth you have to get up to orbital speed then to get past the moon you have to go even faster and to get away from dropping into the sun you have to get faster still,
so a balloon floating in space if it could get there would drift straight into the sun or the nearest gravity field nearest it

however once up to speed 20,000 km p/h plus the speed of the craft can be increased very slightly by using a light(photon) powered sail or to focus lazerbeams on the craft from earth but this is just flea power compared to a short burst of rocket power.
ion power was used to help a recent sucessfull space craft

Fraser
2005-Feb-28, 08:08 PM
I'm pretty sure that a balloon can get outside most of the Earth's atmosphere. The question is, can it increase its velocity to get going to escape velocity. What if you put an ion engine on it and started going sideways and up at the same time, and then venting out gas as your orbital velocity starts canceling out gravity. The only issue that I can imagine is that the balloon would start acting as a brake in the thin atmosphere as your speed picks up - what a drag.

scott712
2005-Feb-28, 09:15 PM
MARS BALLOON!

My favorite Mars Exploration Proposal for a remote probe would be a Balloon that would just blow around, randomly sight seeing. Differences in day and night temperature would cause it to change altitude, even land and take off! It's position could be tracked by installing, I believe as few as four GPS satellites above Mars. (Or would it be MPS?)

What a Video feed that would be! Actual new scenery on a daily basis, and multiple landing sites from one mission!

Even if mission planners were locked into one landing sight initially, there is not reason to spend all our time there!

Wm. Scott Smith

Silverwing
2005-Mar-01, 05:18 AM
[B][FONT=Times][SIZE=1][COLOR=red] <_< You know, I think that a balloon wouldn&#39;t work because it has to float on something&#33;

Sp1ke
2005-Mar-01, 03:14 PM
Bingo&#33; A balloon floats up because it&#39;s lighter than the surrounding air. No air, no float.

A better solution would be a solar sail that uses the solar wind to propel it outwards. But that makes for a difficult and slow return trip.

piersdad
2005-Mar-01, 06:37 PM
there is apparently enough atmosphere on mars to fly a very efficient aeroplane so a balloon is not sci fi for mars
as long as it dont get caught up in some trees

adiffer
2005-Mar-01, 09:08 PM
The balloons meant for floating at an altitude of 30 km start out only a few percent full with respect to helium. You need about 60 cubic meters of volume for that helium for each kilogram of mass if you want to float at that altitude.

Using balloons to go to space is possible, but not in the traditional sense. You have to shape them, strap engines on them and accelerate them to orbital speeds and higher if you want to go anywhere.

Every balloon has a theoretical maximum altitude at which its buoyancy goes neutral. Getting that altitude out past GEO so that no propulsion would be required would currently require unobtanium.

Matthew
2005-Mar-03, 07:42 AM
However what about using baloons to get a satellite and some fuel further from the planet, leave the baloon behind at a certain height, fire thrusters and due to the decreased gravitational force it would require less fuel. This though of course would only work with small satellites, but I wonder if this is a possible way to decrease costs of launching a lightwieght satellite.

piersdad
2005-Mar-03, 07:47 AM
they already do this with rockets taken up to max flying height by large aeroplane and launch from 80 000 feet approx but it is limited to a few kg of actual satelight

gnosys
2005-Mar-07, 01:42 AM
I&#39;m impressed by the plan outlined at the site mentioned above --

http://www.jpaerospace.com/

One airship takes your cargo up to a suborbital space station at 140,000 feet (a stationary helium airship). From there, a bigger airship (which could not survive the weather at lower altitudes) takes the cargo on up to orbit (a five-day trip).

These guys have some money from NASA for one of the elements, and they&#39;re actively doing tests with various components at altitude. They claim they&#39;ll have a manned prototype of the space station within two years. They&#39;re confident they can overcome the various challenges -- the danger of radiation at that altitude, etc.

I don&#39;t know if the plan will work, or whether it&#39;ll end up being economically viable, but I like the pragmatism of the approach -- the fact that they&#39;re out there actually building stuff and testing it at the edge of space, rather than just producing more and more impressive brochures and websites to attract potential investors.

gnosys
2005-Mar-07, 01:43 AM
Anyone know of any similar projects?

piersdad
2005-Mar-07, 02:46 AM
One airship takes your cargo up to a suborbital space station at 140,000 feet (a stationary helium airship). From there, a bigger airship (which could not survive the weather at lower altitudes) takes the cargo on up to orbit (a five-day trip).
i thought the record height for a baloon was well under 140 000 feet.
to go any higher --- well theres no more air to float on.
its like swimming in a pool of water you can float on the surface buit no amount of --lightness-- can make you float above the water
i think the guys at this site

http://www.jpaerospace.com/

are doing research but the design of their balloon is so short of basic knowledge of balooning that the baloon would burst at a height above 10 000 feet with out venting the expanding gass and then they will go no further.

they have their research money and they might contribute some thing to science but it may not be in the science of balloons

adiffer
2005-Mar-10, 02:07 AM
The air pressure at 42 km is around 2mb. There is still air up there on which one can float. It&#39;s not easy to do it, but it is possible.

For those who are curious, we will being doing the high altitude ballooning thing too. We don&#39;t have much on the website right now, so don&#39;t expect sudden enlightenment. 8)

http://gocorp.biz

The trick to getting to those altitudes is to use a double envelope. The gas containing one holds the helium. The outer one bears the loads. Fill the outer one with air and vent it as the helium tries to expand. Provide 60 cubic meters of expansion volume for each kg of vehicle mass and you can float at 30 km. You need a lot more for 42 km.