Question Shuttle to the Moon

[Bonanza123d]

Why not just get the shuttle in orbit around the moon, and hold somekind of ship in the cargo bay that will land. When the mission is done, it'll go up back into the shuttle, and the shuttle will somehow return to Earth.

Maybe you could stick a booster stage or two on the shuttle, and that will get it to the moon and back.

Definitely not practical, but anything is possible in Orbiter.

That booster stage could be another pair of SRBs that would not fire until in orbit ready for TLI burn.


I had an idea for some time on a practical concept. Cut the shuttle bay in half. You then put a apollo heat shield onto it. You finally add 2 SRBs to it. When done, you will have a good spacecraft (Not to mention a good orbiter addon)

 

[Fabri91]

There's a problem: each SRB weighs 590 tons. That's 170 tons more than the entire ISS.

 

[Grover]

i9 had an idea to lift a heavier shuttle, but it can easily be adapted (or enlarged) to make it get the space shuttle FURTHER

the blue and yellow are boosters, to get over the initial gruelling liftoff stage, then the green is an entire stage and the red is another, like a normal space shuttle, but the ET has two stages, engines of its own, and four extra boosters.

its probably best for the tricky direct launches, but what the heck!

note to self: it can always be solved with a bigger launcher

 

[N_Molson]

Ok, lets calculate this the proper way. I take my numbers from Shuttle Fleet v4.7

Orbiter mass, with OMS tanks full : 96,000 kg
Maximum payload : 24,500 kg

Let's assume we install tanks (MMH/N2O4) in the payload bay, which mass are 500 kg empty for the both.

The "internal" OMS tanks can hold 15,200 kg of propellant.

So we get a 24,000 kg from the payload bay tanks, plus 15,200 kg from the standard tanks.

24,000 + 15,200 = 39,200 kg of propellant.

We need the dry mass of the Orbiter :

96,000 - 15,200 = 80,800 kg

We have enough data to feed Tsiolkovski rocket equation, that works very well in our case.

Dv = Ve * ln (120,000/80,800)

Ve is Velocity Exhaust, in the case of the OME it is 3100.

Dv = 3100 * ln (120,000/80,800)

Dv = 1,226 m/s

Even with a 24 tons tank in the payload bay, you can only change you velocity by 1,226 m/s , assuming you burn all the tanks to the last drop. You won't even get a lunar pass, only an elliptic orbit around Earth. I'd guess that the apogee will even be under 10,000 kilometers.

The Orbiter is far too heavy. Three solutions :

a) Get a better ISP. Which means using nuclear power, in the current state of our knowledge. Something like NERVA or VASMIR could be interesting.

b) Make the ship lighter, which means keeping only the cabin and a piece of heat shield : we've got a capsule !

c) Use big solar panels (folded in the payload bay) and Ion engines. It will take a lot of time. And fuel cells will last only 20 days at best.

IMHO the Space Shuttle is one of the worst vehicles for a lunar mission.

 

[Topper]

Hmm intersting here...
So i have two more suggestion (i don't know if this is possible or realistic).

1- Why insert into a lunar Orbit? Why not use just a "free return trajectory"?

2- The Shuttle is not designed for a "High orbit reentry, sure, but maybe the heat shild is good enogh for an aerobraking maneuver!? After a first and (maybe) a second and a third aerobraking, the time period is long enogh that the heat shild can cool down for the next aerobraking maneuver. And if not, maybe it's possible to advance the heat shild for such a mission ;-)

 

[Grover]

the life support only lasts so long, you gotta do it first time or not at all

its true, you can only get a small thing up there, but other than my previous idea (which i now see flaws in) there is an alternative:
on orbit construction, use the shuttle for 3-5 missions taking modules up that assemble a large spacecraft, then if you want, you can sit a shuttle in the middle and use it as the vehicle, or you could just send it on its way after transgressing crew. so the shuttle can help get to the moon, but i doubt one will ever land on the moon

 

[FADEC]

Ok, lets calculate this the proper way. I take my numbers from Shuttle Fleet v4.7

Orbiter mass, with OMS tanks full : 96,000 kg
Maximum payload : 24,500 kg

Let's assume we install tanks (MMH/N2O4) in the payload bay, which mass are 500 kg empty for the both.

The "internal" OMS tanks can hold 15,200 kg of propellant.

So we get a 24,000 kg from the payload bay tanks, plus 15,200 kg from the standard tanks.

24,000 + 15,200 = 39,200 kg of propellant.

We need the dry mass of the Orbiter :

96,000 - 15,200 = 80,800 kg

We have enough data to feed Tsiolkovski rocket equation, that works very well in our case.

Dv = Ve * ln (120,000/80,800)

Ve is Velocity Exhaust, in the case of the OME it is 3100.

Dv = 3100 * ln (120,000/80,800)

Dv = 1,226 m/s

Even with a 24 tons tank in the payload bay, you can only change you velocity by 1,226 m/s , assuming you burn all the tanks to the last drop. You won't even get a lunar pass, only an elliptic orbit around Earth. I'd guess that the apogee will even be under 10,000 kilometers.

Did you calculate a direct insertion?

To be more precise: the person I am talking about claims that the Shuttle does not need to aim for escape velocity because the OMS has enough power to adjust the orbit multiple times to go into a TLO.

---------- Post added at 12:26 PM ---------- Previous post was at 10:26 AM ----------

Okay, and here comes another interesting thought: what about doing it the same way like it was done with SMART-1? Would the payload bay hold enough OMS fuel to reach the Moon like SMART-1 did? And would the payload bay also hold enough life support so that a crew of 2 would survive this mission?

 

[Keatah]

Basically the problem boils down to the shuttle having too much extra mass for LEO operations AND a gliding re-entry. All that "stuff" has to be taken to Lunar orbit and back. And decelerated for a gentle re-entry.

Apollo craft were downright anorexic and lightweight and airy compared to the bloated and densely packed shuttle.

 

[Cras]

Check out the book Back to the Moon by Homer H Hickham. It is based on that NASA internal on getting the Shuttle to the Moon. A bit of a fanastic story, but Hickham worked at NASA and does do a good job keeping the whole thing in a very real tech way. And it is a fun book to boot.

 

[n122vu]

It was actually investigated. Turns out that to enable such a flight the Shuttle and its ET would have to be refueled in LEO, which would take about 13 to 15 lanunches of the Shuttle-C cargo carrier. Possible, yes, but quite impractical. Would be something to try in Orbiter though.

So, we're talking about not jettisoning the ET, but keeping it attached, and using the SSMEs to perform the necessary burns in this particular scenario, correct? That seems more feasible but I still think you would come up short on Dv even after refilling the ET.