Could A Space Shuttle Get To The Moon?

[Photon Guy]

I know the space shuttle was retired in 2011 but could a space shuttle go to the moon? I know back when we did send people to the moon it was with the Saturn V rocket and from what I heard you need a powerful rocket such as the Saturn V to make it to the moon. But if a space shuttle can escape the Earth's gravity, which it obviously can, I see no reason why it couldn't make it to the moon. 

[zapatos]

No, the space shuttle could not go to the moon as it didn't carry enough fuel. The space shuttle never escaped earth's velocity.

[StringJunky]

Zap means gravity, methinks.

[Eise]

5 hours ago, Photon Guy said:

But if a space shuttle can escape the Earth's gravity, which it obviously can, I see no reason why it couldn't make it to the moon. 

It couldn't. Orbiting earth means that the space shuttle did not escape earth's gravity. Why else would it keep in its orbit? Apollo could travel to the point where the gravitation of the earth and moon exactly cancel. Getting over that point means that it 'falls' to the moon. But the moon itself neither escapes earth's gravity, otherwise it would fly away. Escaping earth's gravity for space vehicles means that gravity fields of other objects (planets, moon, sun, ...) have (much) more impact than the gravity field of the earth. 

[Danijel Gorupec]

Could two or more space shuttles do it - by refueling in the orbit? At least an one-way trip... You park one shuttle in the orbit, and then use other(s) to bring more fuel.

[Genady]

7 hours ago, zapatos said:

No, the space shuttle could not go to the moon as it didn't carry enough fuel. The space shuttle never escaped earth's velocity.

The last part meant to be rather "never reached the Earth's escape velocity"?

[swansont]

57 minutes ago, Danijel Gorupec said:

Could two or more space shuttles do it - by refueling in the orbit? At least an one-way trip... You park one shuttle in the orbit, and then use other(s) to bring more fuel.

Not as designed, I think. The shuttle dropped its main tank and solid-rocket boosters. Even if it kept the tank, now you have to continue the launch with the dead weight of the tank and engines. Plus, the fuel was liquid hydrogen and liquid oxygen, so refueling would have been difficult, even if you could haul enough fuel up to LEO - the fuel mass was over 700,000 kg and shuttle payload 23,000 kg - and were able to keep it cold.

[John Cuthber]

You don't need to reach earth's escape velocity to get to the moon. The moon is in orbit, clearly well under the influence of Earth's gravity.

You can't get to the moon with A space shuttle but...
I'm sure there's an XKCD cartoon with a small flattish hill made of fireworks.
How many shuttles would it take to launch a fully fueled shuttle into space?

[zapatos]

2 hours ago, Genady said:

The last part meant to be rather "never reached the Earth's escape velocity"?

Yes, thank you.

6 hours ago, StringJunky said:

Zap means gravity, methinks.

Yes, that way too.

Funny how what you are thinking can get lost in translation on the way to your fingers.

[TheVat]

I what you mean.

Maybe one could combine Clarke's space elevator and a magnetic mass accelerator so that one could accelerate a shuttle without the use of onboard engines until it came off the rails already at some velocity.  You would have some engineering limits, e.g. crushing passengers would not be permitted.  

[Janus]

From the normal LEO orbit for the Space shuttle, you would need ~ 2.2 km/sec additional delta V to attain a Moon intercept trajectory (~1 km/sec less than needed to attain escape velocity).   Using the SSMEs, this would require ~ 50,000 kg of additional propellant, which is about 7% of the mass of propellant in the main external tank at launch.   The shuttle cargo capacity is 24,000 kg.  So, even if you were to fit an additional fuel tank into the cargo hold, you'd come up short.

Now, if you were to put up a secondary fuel tank in a separate launch, and had the Shuttle meet up with it in orbit, you might, with some retrofitting, be able to attach it to the shuttle in much the same way as the external tank was, and give you that extra needed fuel.

Of course, this just gets you to the Moon.  If you want to come back and put the shuttle into the proper re-entry trajectory on return, you'll need to up this fuel requirement considerably.

[Halc]

6 hours ago, John Cuthber said:

You don't need to reach earth's escape velocity to get to the moon. The moon is in orbit, clearly well under the influence of Earth's gravity.

Escape velocity of Earth from the surface is about 11.2 km/sec, and of that energy is needed to get to the moon, which is around 1/2 km/sec from escaping Earth itself.  I wouldn't call that 'well under'.

Similar reasoning shows why it is so much easier to escape the solar system from Earth's orbit than it is to drop an object into the sun, let alone actually go into low orbit around it, which is currently beyond our technological limits.

[Sensei]

1 hour ago, Halc said:

Similar reasoning shows why it is so much easier to escape the solar system from Earth's orbit than it is to drop an object into the sun, let alone actually go into low orbit around it, which is currently beyond our technological limits.

What does this have to do with escape velocity? Artificial satellites simply melt because the temperature exceeds the melting point of any known human materials..

1370 W/m^2 reaches the orbit of the Earth. On the Moon's equator at noon it is the equivalent of 120 C. At a distance of 75 million km from the Sun it will be 5500 W/m^2. At a distance of 10 million km from the Sun it will be 308 kW/m^2. etc. etc.

[Sensei]

Quote

Could A Space Shuttle Get To The Moon?

Obviously:

https://en.wikipedia.org/wiki/Moon,_South_Dakota

ps. But I think it would be a hard landing..

 

[John Cuthber]

13 hours ago, Sensei said:

What does this have to do with escape velocity?

The escape velocity isn't strictly relevant, but it's a proxy for gravitational energy.
Essentially you "drop" your spacecraft towards the sun and it accelerates as it goes.
If you don't fire retro rockets to slow it down, it hits the sun.
It takes pretty much as much fuel to get something "down" as it does "up".

 

 

13 hours ago, Sensei said:

On the Moon's equator at noon it is the equivalent of 120 C

What's the temperature at midnight?
If you make sure your satellite rotates fairly fast you need to look at the average temperature, not the peak.


 

11 hours ago, Sensei said:

Obviously:

https://en.wikipedia.org/wiki/Moon,_South_Dakota

ps. But I think it would be a hard landing..

 

There's a difference between "flying to Moon" and "flying to the  moon".

But...
https://www.tripadvisor.co.uk/Hotel_Review-g5113909-d5113592-Reviews-The_Moon_Inn-Stoney_Middleton_Hope_Valley_Peak_District_National_Park_England.html

[Janus]

17 hours ago, Sensei said:

What does this have to do with escape velocity? Artificial satellites simply melt because the temperature exceeds the melting point of any known human materials..

1370 W/m^2 reaches the orbit of the Earth. On the Moon's equator at noon it is the equivalent of 120 C. At a distance of 75 million km from the Sun it will be 5500 W/m^2. At a distance of 10 million km from the Sun it will be 308 kW/m^2. etc. etc.

From Earth orbit, escape velocity from the Sun is ~ 42 km/sec.  The Earth in it orbit is already moving at ~30 km/sec, so it would only take roughly 12 more km/sec in delta V to escape the Sun.  However, to "drop" an object into a close pass around the Sun, you first have to shed most of the Earth's orbital velocity.  Then if you want to insert it into a circular orbit at that distance, you'll have to shed a good part of the velocity it picked up falling in towards the Sun. 

[paulsutton]

So on a related note,  what about the spacecraft that we launch to dock with the ISS?  that seems small enough.   In order to fly humans to the moon or elsewhere,  would it not need to store fuel and oxygen?   if we didn't fly people then could the same spacecraft hold more fuel.?  and perhaps be automated. 

Is automation a solution here?

 

 

 

 

[zapatos]

18 minutes ago, paulsutton said:

Is automation a solution here?

 

A solution to what?

[paulsutton]

22 minutes ago, zapatos said:

A solution to what?

Getting things around in space,  I would guess the reason the idea of a space shuttle getting to the moon was brought up is because we need to get from earth to the moon or from low orbit to the moon and back.

If we wanted to transport cargo,  then these transport options could be automated to allow more fuel as the need for oxygen for humans is not needed.

 

[Janus]

7 hours ago, paulsutton said:

Getting things around in space,  I would guess the reason the idea of a space shuttle getting to the moon was brought up is because we need to get from earth to the moon or from low orbit to the moon and back.

If we wanted to transport cargo,  then these transport options could be automated to allow more fuel as the need for oxygen for humans is not needed.

 

The mass of the oxygen used per person for a trip to the Moon and back is pretty insignificant. compared to the mass of the person themselves. The real savings in not sending a person is in the mass of the person themselves, not in the oxygen they would use.

[swansont]

I was curious about the amount of oxygen used -

We breath in around 10,000 L of air per day (search results vary from 7500 to 11500), so that’s ~2,000 L of oxygen, but only convert about a quarter of that to CO2, so 500 L. At 22.4 L per mole for an ideal gas, that’s around 22 moles. ~350 grams per day.

[Eise]

12 hours ago, Janus said:

The real savings in not sending a person is in the mass of the person themselves, not in the oxygen they would use.

I thought the real savings are in all the systems needed to keep humans alive.

[Sensei]

On 10/11/2023 at 11:54 AM, John Cuthber said:

Essentially you "drop" your spacecraft towards the sun and it accelerates as it goes.

..and so what? It's a one-way mission anyway, because of what I said earlier. It will melt down..

 

14 hours ago, Janus said:

The mass of the oxygen used per person for a trip to the Moon and back is pretty insignificant.

Oxygen can be (and is) regenerated from CO₂, which is exhaled. "Half" of the Apollo 13 movie is about how to make CO₂ filters. You can have CO₂ to O₂ converters built into the suit.

An interesting option for scuba divers in emergency situations.

 

Edited October 12, 2023 by Sensei

[iNow]

1 hour ago, Eise said:

I thought the real savings are in all the systems needed to keep humans alive.

Of course, but the billionaire can barely care about the loss or gain of a penny. The issue here is one of scale. All systems are relevant, but some are marginal enough to be mostly dismissed in this context. Janus is far more capable than me of responding, just adding my own thoughts to this particular critique which strikes me as somewhat specious. 

[swansont]

2 hours ago, Sensei said:

Oxygen can be (and is) regenerated from CO₂, which is exhaled. "Half" of the Apollo 13 movie is about how to make CO₂ filters. You can have CO₂ to O₂ converters built into the suit.

An interesting option for scuba divers in emergency situations.

The Apollo CO2 scrubbers removed CO2 but did not regenerate oxygen. LiOH is converted to Li2CO3 and water.

If you regenerate the oxygen you require extra mass and energy. The Apollo fuel cells used oxygen to generate power, so is there even a net saving?