Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

PLIND · 2004-05-01 17:09:56

Here's a simple idea, I just want to know if it's been thought of and/or tried.

You have a spacecraft that will use one of the new, clever methods of propulsion for getting from LEO to Mars. As I understand it, as a result of viewing a number of different threads, the number one biggest challenge at the present time is the cost etc of getting a fair sized payload into LEO (Hope I'm correct with that statement?). This spacecraft sits on top of a very large inflatable baloon/s (for lack of a better word). However, this large balloon is integral (not discarded) to the ship, it is filled with hydrogen, not helium!
It provides initial lift for the spacecraft. After the craft has reached the appropriate altitude and acceleration the hydrogen is funnelled into the spacecraft's engines and ignited. Now the craft is really taking off! The balloons are reduced in size as the hydrogen is used up. Eventually the balloons are stored inside/outside the spacecraft as it leaves Earth orbit. There is a reason we do not discard these balloons, they double as living/planting/radiation protection areas etc for the trip to or upon reaching Mars. On the return trip they could be used in a similar manner (filled with Martian hydrogen) to assist the craft leaving Mars after their use on the trip/surface.

Now I know this sounds kind of strange but think about it, I think it is very efficient use of materials? I'd like to know why this is not an excellant way to get a martian trip started?

Cheers,

PLIND

???

GCNRevenger · 2004-05-01 17:36:36

Ain't gonna happen...

-Not enough hydrogen in the balloons to use for rocket fuel. Dozens of tons would be required

-Difficult to vacuum up hydrogen gas fast enough to feed a rocket engine

-Lag time between balloon deflation and engine overcoming weigh + drag would cause loss of altitude

-Giant balloons not suited for pressurized volume... TransHab's walls are almost two feet thick

PLIND · 2004-05-01 17:55:54

Thanks for the reply GCNRevenger.

Does that mean that a dome on the surface of Mars intended for growing food etc is 2 ' thick? That's going to create a challenge?

Is there no argument for using helium/hydrogen for initial lift? Doesn't lifting all that weight up several miles buy us anything? How high would a hydrogen baloon reach before topping out?

Cheers,

PLIND

Euler · 2004-05-01 18:53:11

Does that mean that a dome on the surface of Mars intended for growing food etc is 2 ' thick? That's going to create a challenge?

The reason why transhab is 2 feet thick is to stop micrometiors and radiation. This would not be as necessary on Mars because of Mars' atmosphere, so a dome on Mars could have thinner walls.

GCNRevenger · 2004-05-01 20:07:56

The height you can reach depends quite a bit on the payload... The big problems with balloon launch are low payload mass and no inertia at launch altitude, that it would require a balloon of unreasonable proportion to lift a rocket big enough to climb the other 80% of altitude and reach Mach-25 laterally. The big F-1 rocket stage on the Saturn-V contributed a large amount of lateral inertia. Just climbing 20mi high isn't that useful, its easier just to build a bigger rocket.

Ian Flint · 2004-05-04 08:56:21

Just curious.

How high can a hydrogen balloon climb without any payload. I'm looking for a theoretical limit using all the latest technology.

PLIND · 2004-05-06 17:07:37

One of the canadian X-prize entries (http://www.davinciproject.com]www.davinciproject.com) shows the balloon phase reaching a max at 24,400m.

PLIND ???

Mark Friedenbach · 2004-05-06 22:32:34

Just curious.
How high can a hydrogen balloon climb without any payload. I'm looking for a theoretical limit using all the latest technology.

Depends on what it's made of. Just calculate the weight of the balloon + payload, the volume of the balloon, and from there the buoyant force. The weather balloons used for x-ray astronomy can lift a fair sized payload to 100,000ft with about $80,000 of helium.

laser737 · 2004-05-21 18:26:14

Hi , i must build a blimp (car balloon) and would like to know how many payload (grams) 1mt³ of balloon mix( He²+H² ) can to lift?

Euler · 2004-05-21 19:48:07

How high do you want your ballon to go?

laser737 · 2004-05-22 11:02:00

....about 6 meters only, ll be a R/C balloon with a car shape 1:1. i ll use radio controll and engines, i need know: HOW MANY THRUST HAVE 1 mt³ OF GAS BALLOON, cause i need calculate the weight of propulsion, controlls wardware and balloon skin.The car balloon ll use about 9 m³ of flyballoon gas.

Rxke · 2004-05-23 04:55:43

http://www.msnbc.msn.com/id/5025388/]You want a balloon? you got one!

... That guy thinks big...

bolbuyk · 2004-05-24 06:23:18

Hi , i must build a blimp (car balloon) and would like to know how many payload (grams) 1mt³ of balloon mix( He²+H² ) can to lift?

Calculating the lifting capabilities of a balloon.

The law of Archimede: The force putting something up is equal to the weight of the stuff that is put away. In this case, surrounding air is put away, instead of it comes your mix of He and H2 (He2 doesn´t exist).

First it is importaant to know the mix-numbers of He and H2. From this you can calculatee the molecular mass of your mix, which is the weighted mean of the two components. Eg when you havee a volumetric mix of 1:1 (Which in case of gases is equal to a molecular 1:1 mix) the molecular mass is .5x4+.5x2=3 g/mol

Then you substract from this molecular weight the molecular weight of the air, which is about 29 g/mol. Difference is -26 g/mol, which implies you can consider your balloon as something with a negative weight.

Then with the gas-law you calculate the lifting properties. At sea-level, airpressure is 101325 Pa, T is about 390 K, depending on the place where you are, the general Gas-constant is 8.3145. The laws are:

pV/T=nR and m=1000xMn

p is pressure (Pa)
V is volume of balloon (m3)
T is temperature (K)
n is amount (mol)
R is gas-constant (8.3145)
m is (negative!) mass (kg)
M is (negative!) molecular mass (g/mol)

So you can calculate an imaginable negative mass. This can be compensated by a positive mass (That what you want to lift up) to get a net-mass of 0. In that case it flies.

samardza · 2004-06-01 21:57:23

Hi , i must build a blimp (car balloon) and would like to know how many payload (grams) 1mt³ of balloon mix( He²+H² ) can to lift?

Unfortunately at sea level, 100% purity, and 100% inflation H2 lifts about 75#'s per 1000 cubic feet, and He about 65#s. as a ballpark it work out to about 1 KG per cubic meter. Pre WW2 the german zep crews allowed 1% inflation per 100 Meter's of altitude. The expansion is the reason that WW1 "height climbers", which reached 26000 ft had nearly half of their sea level lift taken by ballast.

SpaceNut · 2018-05-04 18:29:57

bump will need to fix the topic

SpaceNut · 2018-05-04 20:13:10

Oh the how to defeat gravity mass equation not going to work.....

New Mars Forums

Announcement

#1 2004-05-01 17:09:56

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#2 2004-05-01 17:36:36

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#3 2004-05-01 17:55:54

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#4 2004-05-01 18:53:11

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#5 2004-05-01 20:07:56

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#6 2004-05-04 08:56:21

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#7 2004-05-06 17:07:37

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#8 2004-05-06 22:32:34

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#9 2004-05-21 18:26:14

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#10 2004-05-21 19:48:07

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#11 2004-05-22 11:02:00

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#12 2004-05-23 04:55:43

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#13 2004-05-24 06:23:18

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#14 2004-06-01 21:57:23

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#15 2018-05-04 18:29:57

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

#16 2018-05-04 20:13:10

Re: Is this a new idea for getting to LEO? - A possible efficient way to get to LEO?

Board footer