Superman - Shuttle

[ecoli]

Warning... this thread may contain spoilers.

 

 

I just saw the movie yesterday, and I had to laugh at a shuttle being launched off a 747. Even if this is possible (is it?) the force required to launch the shuttle into space would be really great, so wouldnt it push the 747 backwards too much. They didn't show that at all in the movie though.

 

Not to mention the amount of fuel it would take for a 747 to carry a space shuttle.

[Cap'n Refsmmat]

747s do carry Space Shuttles routinely, but they never launch them.

[Sisyphus]

I wouldn't think a space shuttle by itself could possibly carry enough fuel to get into orbit from any altitude a 747 could reach carrying all that weight.

[Cap'n Refsmmat]

The Space Shuttle actually only carries enough fuel to alter its orbit by a few miles - the rest is all in the external tank and boosters.

[SmallIsPower]

I've googled the gross mass for the shuttle & 747

 

Shuttle 2,000,000 kg

747 300,000 kg

 

I'm surprised it can carry the shuttle anywhere, yet I've seen the pictures of 747s carrying shuttles.

[insane_alien]

small, thats a fully fuelled shuttle stack(the orbiter, ET and SRB's)

 

the orbiter only weighs in at about 50 tonnes. the shuttle can kind of be launched from a 747 but its more of a pull up over the tail and glide down thing.

[ecoli]

small' date=' thats a fully fuelled shuttle stack(the orbiter, ET and SRB's)

 

the orbiter only weighs in at about 50 tonnes. the shuttle can kind of be launched from a 747 but its more of a pull up over the tail and glide down thing.[/quote']

 

In the movie, the shuttle would (not entire sure of the correct terms here) use it's engines to thrust off the 747. Knowing how much velocity is needed to break earths atmo, you could calculate the probable speed of the shuttle at take off. Knowing the mass, you could then calculate the force imparted to the 747, and then calculate how much 'kickback' the 747 would take. Right?

 

I wouldn't be surprized if a 747 would be destroyed in such a process.

[ydoaPs]

On takeoff, in real life, the sound of the engines alone would smash the shuttle to pieces. That is why they have the water.

[Cap'n Refsmmat]

The water sprayers are left over from Apollo when the sound of the engines could blast the roof off of the press building three miles away. I'm not sure what effect the orbital maneuvering system (the only system that works without the external fuel tank) would have on a 747.

[scicop]

The funny part to all this is that the shuttle cannot fly!!! I.e. its wings do not give it any form of lift that can sustain flight, especially at the maximal altitudes that a 747 can fly!

 

Basically the space shuttle is nothing more than a "rock" with a body-shape/ wings that allow for a "controlled" drop (i.e. some steering capabilities), so forget about a shuttle being able to escape earth's gravity at the maximal height that a 747 can fly.

 

P.S. I've had the pleasure of meeting two astronauts in person, including one from the Neruolab mission (a MD, PhD, and guest lecturer who ran one of my journal clubs in grad school), and his video(s) were amazing! Basically had footage (from escorting jets) showing how the shuttle (his own) just dropped like a rock upon reentry. Basically the escorting jets were in a kinda of nose dive to keep up with the shuttle...neat footage..direct from NASA.

[padren]

I haven't seen the movie so I don't know if the shuttle in question was trying to achieve a stable orbit or just escape earth's atmosphere, but you need a heck of a lot of forward velocity to get into orbit.

 

If you are not moving forward, you'd have to go into geosynchronous orbit to not fall, which from wikipedia is:

 

A circular geosynchronous orbit in the plane of the Earth's equator has a radius of approximately 42,164 km (from the centre of the Earth) or approximately 35,786 km (22,236 statute miles) above mean sea level.

 

According to the same source to enter low earth orbit (200 - 1200 km (124 - 726 miles) ) you'd need to be travelling forward at 27,400 km/h (8 km/s) to stay up.

 

It also says the Boeing 747 travels "typically mach 0.85 (1041 km/h)" so that little shuttle would really have to kick it to both get up and get into orbit....not much chance of that.

[ecoli]

I wonder though, would you still need the same escape velocity if you're starting from higher up?

[Cap'n Refsmmat]

padren: The space shuttle is not capable of reaching geosynchronous orbit. Only up to about 400 miles.

[padren]

padren: The space shuttle is not capable of reaching geosynchronous orbit. Only up to about 400 miles.

 

I know, its a low orbit craft. I was citing geosynchronous orbit as the only means to achieve orbit without immense laterial velocity, which it cannot do even with the full solid rocket boosters and external fuel tank, and to achieve the laterial velocity required for a low orbit would be impossible from a boeing 747.

 

 

 

Speaking of shuttles its great to see Discovery off to a great start today.

[Cap'n Refsmmat]

You can't go into geosynchronous orbit without lateral velocity, even if you were directly at the equator.

[Evil Genius]

Even though I havent seen Superman yet, I think what you are talking about has already happened in a movie. If i remember right, it was also used in beginning the Bond film Moonraker when the villain got his men to hijack back a shuttle.

Of course, the 747 carrying it was blown up as the shuttle flew off the top of it.

 

(Is that what you are on about?)

[padren]

You can't go into geosynchronous orbit without lateral velocity, even if you were directly at the equator.

 

Lateral velocity relative to the surface of the earth, since we were looking at a scenario when the shuttle was being launched from the back of a jet that was within the moving atmosphere.

 

You still have to be able to circle the earth every 24 hrs but we are doing that right now sitting in our chairs.

[SmallIsPower]

Then the 747 could use lift and turn to get away from the shuttle's launch. There are scramjets that don't function until hypersonic velocities, should an engine be designed for efficency only at supersonic speeds, the 747 would be a plus, in addition to whatever altitude the 747's lift provided. It would never be a great improvement, but it could help somewhat.

[ecoli]

I just saw the movie again, and I should correct myself. The plane was a 777 not a 747, if that makes a difference.

[SmallIsPower]

for what it's worth- The 777-300ER contains many modifications, including the GE90-115B engines, which are currently the world's most powerful jet engine with 115,300 lbf (513 kN) thrust.

 

There's a 777 frieghter coming out too.