Question about space shuttles, space and leaving orbit

[Combat squirrel]

As title, just listening to the podcast of the close out of discovery last month. Find it all interesting, people’s experiences working on it.

Then something occurred to me, it was designed as an earth orbiteer, BUT theoretically, if they fitted the biggest fuel tank possible in its cargo bay, given the maximum launch weight, SURELY there would have been enough fuel to send it to the moon. I remember reading that the Apollo space crafts stage 3 only burned for a few minutes to send it moonwards ?

Even if it was only *just* possible they could have done a free return trajectory around the moon so they didn’t have to burn more fuel to come back to earth.

So is it theoretically possible? If not why not and if it is, why didn’t they do it ? It would have made the USA look like they still had the ability to do lunar trips.

ALSO could; in theory, we send ISS to the moon in a lunar orbit? Obviously im thinking a lot less likely given that it’s a sprawling fragile structure compared to the space shuttles relatively solid construction (i.e. it can fly in atmosphere and not be damaged so it could im sure survive the inertial energy of accelerating to the moon)

Of course im guessing we would have to launch a fairly hefty rocket motor and fuel tanks to the ISS 1st to give it the required power to leave earth orbit, sort of basically bolt the engine to the ‘back’ of the ISS and give it some welly.

Anyways your input OCUK is most welcome, I like theorizing on such things, stuff that’s a little unusual, but surely not impossible………..

 

[PistolPete]

I'm not sure on the answer as to "could they" but my question would be "why would they".

Costs of doing so against what they would gain from doing so may be the reason why.

 

[Combat squirrel]

"why would they".

Off top of my head:

1) Huge range of experiments in another 'space environment' outside of earth orbit, i.e. more distance away from earths magnetic field

2) Many experiments with 'deep space' radiation

3) Close up analysis of lunar orbit, the lunar surface from orbit.

4) Remote control of lunar robots with no time delay

5) geo sync orbit of the moon or an orbital speed around the moon staying on the 'dark side' of moon, i.e. the moon always blocking the sun for a quiet spot to use sensitive deep space telescopes (i.e. cold and not much of the earths / suns influence


Im sure there are many thousands more reasons, but those I can think off top my head quickly.

 

[checjb]

6) Get anyway from Magick's sulphur fire/fumes

 

[Combat squirrel]

6) Get anyway from Magick's sulphur fire/fumes

Say what ?

What im asking is perfectly reasonable, the space shuttles main engines im sure are powerful enough to send it to lunar orbit, its just the required fuel and the orbiters mass, it can be answered with math, I just don't know the formulas.

 

[touch]

Off top of my head:

1) Huge range of experiments in another 'space environment' outside of earth orbit, i.e. more distance away from earths magnetic field

2) Many experiments with 'deep space' radiation

3) Close up analysis of lunar orbit, the lunar surface from orbit.

4) Remote control of lunar robots with no time delay

The moon is not as far away as you seem to think. On average, its around 220,000miles. My car has almost driven that far.
Its not outside of Earth's orbit or away from Earth's magnetic field and it's definitely not 'deep space'.

edit: by my (quite possibly incorrect) calculations, the delay in sending a signal to something on the surface of the moon would be 1.18 seconds

 

[Tefal]

As title, just listening to the podcast of the close out of discovery last month. Find it all interesting, people’s experiences working on it.

Then something occurred to me, it was designed as an earth orbiteer, BUT theoretically, if they fitted the biggest fuel tank possible in its cargo bay, given the maximum launch weight, SURELY there would have been enough fuel to send it to the moon. I remember reading that the Apollo space crafts stage 3 only burned for a few minutes to send it moonwards ?

Even if it was only *just* possible they could have done a free return trajectory around the moon so they didn’t have to burn more fuel to come back to earth.

So is it theoretically possible? If not why not and if it is, why didn’t they do it ? It would have made the USA look like they still had the ability to do lunar trips.

ALSO could; in theory, we send ISS to the moon in a lunar orbit? Obviously im thinking a lot less likely given that it’s a sprawling fragile structure compared to the space shuttles relatively solid construction (i.e. it can fly in atmosphere and not be damaged so it could im sure survive the inertial energy of accelerating to the moon)

Of course im guessing we would have to launch a fairly hefty rocket motor and fuel tanks to the ISS 1st to give it the required power to leave earth orbit, sort of basically bolt the engine to the ‘back’ of the ISS and give it some welly.

Anyways your input OCUK is most welcome, I like theorizing on such things, stuff that’s a little unusual, but surely not impossible………..

hugely expensive and you just removed your payload so no landing.


also would put astronauts at risk by having them exposed to radiation for longer.

all for very little gain and phenomenal cost.

Probably quite risky too.

 

[PistolPete]

6) Get anyway from Magick's sulphur fire/fumes

I couldn't work this out at first.....

 

[Blinkz]

As has been said, simply there was no reason to do it. The Apollo program cost over 20 billion dollars and was basically a PR stunt. Sure they learnt a lot and it was an amazing achievement, however it was NOT cost affective.

The whole aim of the space shuttle was to try and make space travel cost affective. Being able to reuse the orbiters and SRBs to keep the costs down. They would be able to launch large numbers of commercial satellites and make a profit out of space travel. It was realised that this was never going to happen and as such it was then decided that the main goal of the STS was to build the ISS, to do all of the experiments etc that you mention. There was no benefit to returning to the moon.

Could the shuttle of done it? Yes probably it could have been retrofitted to get into lunar orbit and back, but again why? There is no difference in a lunar orbit then in earth orbit for the reasons you talk about. The shuttle would never have been able to land on the moon, not without huge modifications at ridiculous costs.

 

[Combat squirrel]

The moon is not as far away as you seem to think.
Its not outside of Earth's orbit or away from Earth's magnetic field and it's definitely not 'deep space'.

I know exactly how far it is thanks, and its defiantly out of low earth orbit It is far enough to have significantly different magnetic field properties. Course not deep space in universal scales but statistically way further than a couple of hundred miles obviously

hugely expensive and you just removed your payload so no landing.


also would put astronauts at risk by having them exposed to radiation for longer.

all for very little gain and phenomenal cost.

Probably quite risky too.

Yeah I never said we would land, also you could not fill the cargo bay with fuel, to heavy, so there would be room for a Columbus experiments module or similar, significantly more room than an Apollo, the idea would be scientific experiment.

Cost would be something, but id imagine not massive amounts or much more than a normal shuttle flight, you would just need a way to pump fuel to the engine from cargo bay, this may of been designed into the shuttle anyway as far as I know.

Risk, no more than flying into earth orbit, I guess the only risk would be a 3 day return time as opposed to less than an hour from earth orbit if wanted to get to earth ASAP.

Radiation, not that much, infact as far as I know its not worse than low earth orbit and you fly fast through the radiation belt around earth, forget its name, allen belt or something.


I think my main point is, to achieve lunar orbit would ironically not have cost much more at all than just flying a shuttle into orbit.

So im thinking relatively low cost for distance/science/PR than we probs think.

My only curiosity would be hitting the atmosphere at 25000mph instead of 17500 on return from the mun.

 

[touch]

I know exactly how far it is thanks, and its defiantly out of low earth orbit

Yes, correct....but thats not what you said earlier:

outside of earth orbit

The moon is not 'outside of earth orbit'.

 

[Blinkz]

I think my main point is, to achieve lunar orbit would ironically not have cost much more at all than just flying a shuttle into orbit.

This is where you are wrong. It would be significantly more expensive to go. You can't just chuck a fuel tank into it and fit a hose to the engines.

 

[Tefal]

Radiation, not that much, infact as far as I know its not worse than low earth orbit and you fly fast through the radiation belt around earth, forget its name, allen belt or something.

during the journey you're not protected like in low orbit, one flare and everybody dies.


also the old Apollo astronauts are all suffering from catteracts etc from the radiation they were exposed to on lunar trips.

 

[SillyHeatsink]

It is not theoretically possible. The shuttle could not contain enough fuel in its payload bay (4,6 x 18m) to allow it to get to the Moon and take off again.

A free return trajectory is only really intended for use used in complete utter SHTF emergencies. They're highly dodgy manoeuvres; you wouldn't want one as the backbone of your flight plan.

Can you explain what the phrase 'inertial energy' means? Haven't come across the concept before.

 

[Blinkz]

Its not just a matter of fuel. Its about thrust. The escape velocity for a lunar injection is much high then just LEO, the shuttles engines don't have the power to lift the weight of fuel needed. It only gets into LEO with the help of the SRBs!

 

[Combat squirrel]

Yes, correct....but thats not what you said earlier:



The moon is not 'outside of earth orbit'.

Yeah but an orbit is an orbit from 200 to 500000 miles, it only stops being an orbit when Lagrangian points are reached. Kind of both barking up the wrong tree with that debate,lol.

This is where you are wrong. It would be significantly more expensive to go. You can't just chuck a fuel tank into it and fit a hose to the engines.

Yeah I know its not quite that simple, but its not silly difficult, the shuttle pumps fuel from the external tank and then drops it when its finished, so the config internally is already there for tank switching on the fly, just have to add another 'junction' in the piping from the cargo bay....speaking in simple terms.

during the journey you're not protected like in low orbit, one flare and everybody dies.


also the old Apollo astronauts are all suffering from catteracts etc from the radiation they were exposed to on lunar trips.

It's not that bad as far as I know, besides the shuttle could have a 'refuge' tank from the airlock, i.e. a fairly shielded area on detection of solar spikes, and generally there not frequent.

Remember this is a cool 'what if' discussion, half serious and half fun dreaming it up

 

[Tefal]

shielding is heavy.

very heavy.

 

[Combat squirrel]

It is not theoretically possible. The shuttle could not contain enough fuel in its payload bay (4,6 x 18m) to allow it to get to the Moon and take off again.

Can you explain what the phrase 'inertial energy' means? Haven't come across the concept before.

Im only talking about going to lunar orbit and back not at all landing. Soyuz was originally designed for lunar orbit trips, they both have similar engine power.

I was trying to explain (albeit in caveman terms,lol) the forces exerted upon the space craft as it accelerated from 17500 to 25000mph

Its not just a matter of fuel. Its about thrust. The escape velocity for a lunar injection is much high then just LEO, the shuttles engines don't have the power to lift the weight of fuel needed. It only gets into LEO with the help of the SRBs!

This is true, but, you can have a low thrust ONCE your in orbit to leaving orbit, they got from orbit to lunar orbit with one engine on apollo. Remember there is a MASSIVE difference from accelerating a 3000 ton object sitting at sea level to a 100 ton object already sitting in orbit at 17500, I.E. thousands of times less power required.

You just need enough continuous thrust to increase your apoapsis (kerb space program player here )

 

[Blinkz]

Its not that simple to assume you just need low thrust to accel to a certain speed. Its about Delta-V. Read this http://en.wikipedia.org/wiki/Delta-v to understand it better.

 

[Combat squirrel]

Its not that simple to assume you just need low thrust to accel to a certain speed. Its about Delta-V. Read this http://en.wikipedia.org/wiki/Delta-v to understand it better.

From what I get from that and I know bugger all about the math, I need approx 7.5-9kps to increase by 1.6kps (km per second) to go to the moon.

Still makes interestin convo didnt anyone here draw space ships at school, or design new ships when should have been doing school work, lol.

Kerbal SP while a game uses 'real' orbital simulation for its physics, not a great deal of power is needed compared to take off to fly to the mun, assuming the same applies in real life, ill have a google.

EDIT: This is a good read:

http://www.permanent.com/space-transportation-earth-moon.html

seems if you want to launch a geosync satallite, if you launched it from the moon it requres 10 times less energy, not quite what im lookin at, but a good indicator of power/mass ratios once we get further from earth.

Also the further away from earth you get - the less earths mavity is an influence, thus you can slow your kinetic energy speed in comparison to the potential energy, i.e. you apply 'x' thrust in the space shuttle, and the further from earth you get the faster the ship will go, increasing its speed, or maintain a constant acceleration curve requires you have less power from the shuttle as you get further from earth, so maintaining the same acceleration, you would have to gradually lower the power of the engine as you go.........I think anyways.