Foxster

2001: A Space Odyssey rocket launch

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In the slow-burning start to the book 2001, Floyd leaves Earth in a horizontally-launched rocket on a track that curves up through 90°. 

In the 1951 movie "When Worlds Collide" there is something similar, with a rocket launched along a track down into a wide valley and then up the other side to be released from the track at a steep angle. There are other examples from the era. 

EjBZKMJ.png

As far as I know, there have been no practical deployments of this launch style. So, why do you think several sci-fi writers and film-makers thought this was going to be the launch method of the future and does it have any merits?

Edited by Foxster

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I see with the Hyperion concept that a first "stage" would be provided by a re-reusable rocket powered sledge, so I can see some advantages with that. 

Obvious downside being the need for a 1.7km high mountain. 

Still leaves me with the question of what problem with vertically-launched rockets the concept was designed to overcome.  Ability to launch with lower TWR? More fuel efficiency? Safer? A semi space-plane advantage with some lift from wings?...

Edited by Foxster

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I just reread the relevant passage in my copy of 2001, and while the launch described does involve a track, there is no mention of the upward curve. 

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12 minutes ago, Kerwood Floyd said:

I just reread the relevant passage in my copy of 2001, and while the launch described does involve a track, there is no mention of the upward curve. 

Oh, my bad. I was assuming the upward curve and perhaps remembering the launch in When Worlds Collide as there was no Earth launch scene in the movie 2001

Similar idea though still I suppose. 

Edited by Foxster

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I would assume that the author wasn't an aerospace engineer and didn't know how to stabilize a rocket other than aerodynamically?  Launching it from a long track might give the rocket enough speed to be stable?  

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The track ideas have clearly been around a while. The Hyperion concept only gives the vehicle 300 m/s, though clearly that's a lot of propellant the vehicle doesn't have to carry (and the sled can be arbitrarily large, and easy to reuse). Phil Bono threw a lot at the wall to see if anything would stick. He had done the math, and knew the only way to do what people wanted to do required massively reducing costs via reuse.

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27 minutes ago, Xd the great said:

How high would the bending gee forces be?

Also: launching a rocket from a vehicle:

https://goo.gl/images/hJJTxh

 

Not really. The Crawler Transporter does carry the Mobile Launch Platform to the pad, but then the MLP is locked in place at the pad and the CT is withdrawn before launch.

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Well. It was the time when people learned that rockets can actually lift off vertically and adding anything including wings only makes things worse ...

37 minutes ago, Xd the great said:

How high would the bending gee forces be?

https://en.wikipedia.org/wiki/Acceleration#Tangential_and_centripetal_acceleration

Edited by Green Baron

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Thinking about it, the V1 launched on a disposable sled running along an angled track. That would have had some practical benefits in terms of providing a smooth portable runway. Perhaps this is what inspired writers as footage of their launch might have been their only experience of "rocket" launches. 

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1 hour ago, Foxster said:

Thinking about it, the V1 launched on a disposable sled running along an angled track. That would have had some practical benefits in terms of providing a smooth portable runway.


It wasn't portable - it was a massive fixed installation, very visible and very identifiable from the air.
 

1 hour ago, Foxster said:

Perhaps this is what inspired writers as footage of their launch might have been their only experience of "rocket" launches. 

Footage/images of V2 launching vertically would have been available too.

 

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Another fictional example from the 1960s was Gerry Anderson's Fireball XL5:

https://www.youtube.com/embed/u7LMlr9cWO4?start=31&end=50

I guess that as in that series they simply ignored the lack of gravity in space, they could also hand-wave the enormous vertical acceleration on that short ramp.  (Not to mention the shadow of the exhaust on the sky...).   Simpler times.

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10 minutes ago, DerekL1963 said:


It wasn't portable - it was a massive fixed installation, very visible and very identifiable from the air.
 

Not quite "portable" true but there was a kit form that meant the whole thing could be delivered and setup  from a couple of trucks. 

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Bono talks about Hyperion in his book from the late 1960s. I think it was in a chapter about early attempts to reuse rockets, and it was really to buy some margin by loading a % of props onto the sled, instead of carried on the spacecraft. It was subsonic, so we're talking about under 343 m/s total dv given the vehicle. As a reality check, that's maybe the first 20 seconds of a launch. It's similar to air-launching, really.

Still, very limiting in terms of spaceport location (though they could put one right near my house, lol).

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As others have noted, it's hard enough to make a rocket which can resist the vertical compression of riding on its thrust against gravity, so making one which could also resist bending forces as it moved through a curve would complicate the problem and add to structural mass. And as we know from playing KSP, you'd want to launch vertically to get through the thickest part of the atmosphere as quickly as possible, and coming off a launch facility at anything other than 90 degrees to the ground would prolong that. In short, a swoop like this would seem to make things harder rather than easier. 

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On 11/30/2018 at 5:07 PM, RealKerbal3x said:

Not really. The Crawler Transporter does carry the Mobile Launch Platform to the pad, but then the MLP is locked in place at the pad and the CT is withdrawn before launch.

This, the crawler takes the rocket and the bottom structure including the launch tower to pad. 
Russia and spacex uses an horizontal assembly and an rail with an ejector at the end. 
Note that this get less practical with huge rockets as in saturn 5, space shuttle, N1, buran and probably BFR. 

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Why make the launchway vertical? It should be horizontal and finish at several kilometers above the sea level.

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5 hours ago, kerbiloid said:

Why make the launchway vertical? It should be horizontal and finish at several kilometers above the sea level.

I doubt that either the plateau in the Himalayas* or the Andes would be high enough for a "pre-completed" pitchover.  Your best bet would be to run up a mountain, although the obvious places in Ecuador have somewhat populated areas (often in Brazil) downstream, as does Leadville, CO.

I'm pretty sure the whole idea is to "get away" with lower TWR as you go up the rail (at a slope instead of vertical).  Having fuel in the sled sounds like a great idea, but I'm not aware of any asparagus/drop tanks in actual use (the Electron does have "drop batteries").  This whole idea appears to have been replaced by solid boosters, which give you "cheap" TWR for that initial thrust much farther than any practical rail.

* China has a launch site with some serious elevation.  I'm pretty sure they go even higher before completing the pitchover.

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38 minutes ago, wumpus said:

I doubt that either the plateau in the Himalayas* or the Andes would be high enough for a "pre-completed" pitchover.  Your best bet would be to run up a mountain, although the obvious places in Ecuador have somewhat populated areas (often in Brazil) downstream, as does Leadville, CO.

I'm pretty sure the whole idea is to "get away" with lower TWR as you go up the rail (at a slope instead of vertical).  Having fuel in the sled sounds like a great idea, but I'm not aware of any asparagus/drop tanks in actual use (the Electron does have "drop batteries").  This whole idea appears to have been replaced by solid boosters, which give you "cheap" TWR for that initial thrust much farther than any practical rail.

That's true for a vertical launch. But it probably can ease a horizontal one, allowing to use HTHL SSTO.
This of course won't help with superheavy payloads, but would be nice for 10..40 t capable crafts (so in most cases). To replace every rocket less capable than Saturn V.

They launch anti-aircraft missiles with ramjets with solid boosters.
Let's equip a spaceplane with a hybrid ramjet/rocketjet (like in KSP). Let replace the boosters with maglev.

The initial speed for ramjet ignition is ~2.5 M.
Not so much.

The initial altitude to reach it safely is ~several kilometers.

Early projects (1950s-60s) required turbojets to reach the ignition condition.
Let's replace these turbojets with a maglev and make the plane much lighter.

Edited by kerbiloid

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3 hours ago, kerbiloid said:

The initial speed for ramjet ignition is ~2.5 M.

You can ignite them somewhere between .5-.8 mach, although don't expect much thrust (and I'd expect the ability to do so will limit efficiency at high speed).  Top speed is no higher than mach 6 (you might as well ignite a rocket stage at that point).

The biggest problem for this type of idea is that the Stratolaunch jet is more or less complete, and could lift such a payload to "several kilometers" and drop it at some subsonic level (and presumably dive to some ignition point).  Once it ignites, at best you will leave the atmosphere approaching mach 6 and can use essentially vacuum-optimized nozzles (I suspect that the need to keep the nozzle finite will cut it off more than the need to optimize for the thin atmosphere).

So you get maybe 2000 m/s out of your first stage, and it isn't entirely clear how expensive reusable ramjet engines are: the only ones I can think of were on the SR-71 blackbird - at speed they essentially ran in "ramjet mode", and would require an "impossible" amount of launches to justify such an engine over using 2000m/s worth of solid rockets (of course, this includes the compressors used to get to speed, so maybe you can make them much cheaper).

Before KSP I was a huge fan of air breathing engines.  Since playing, only the X-43 (which was still accelerating at mach 6.8 and could even have "net positive thrust" at mach 11) seems to have the delta-v necessary to justify such a thing.  But at least the Stratolaunch aircraft gives the whole idea the "zeroth stage" such a rocket would need: I don't think anyone would want a rail unless negotiations for the thing completely bogged down.

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44 minutes ago, wumpus said:

You can ignite them somewhere between .5-.8 mach

1. To take as much from the external power source as possible.
2. Why use subsonic+hypersonic+rocket 3-in-1 engines when can 2-in-1, without sub-.

44 minutes ago, wumpus said:

Top speed is no higher than mach 6

(10 M iirc, but no matter).
Yes, and (as this has been proposed in the 1960s designs) while ascending, it should scoop and store the liquid oxygen.

The spaceplane starts with full hydrogen tank and with empty oxygen one.
While it is accelerating with ramjets, it fills the oxygen tank with the oxygen from the air intake. Unlike other planes, its mass is increasing during the aerial phase of flight.

Once it has reached altitude ~25-30 km and speed up to 8-10 M, it has its oxygen tank full, while the external air is thin.

It switches the engine from ramjet mode to the rocket mode and spends the rest of the hydrogen and the stored oxygen.

It reaches the lowest orbit, releases the payload, performs 1-2 turns and makes a retroburn.
Then it vents out the oxygen remains.

It aerobrakes like any spaceplane.
At 25 km and ramjet-friendly speed it opens the intakes and performs a ramjet flight to the runway.
Then lands as a sailplane, like Shuttle.

Then it's recovered, lifted up to the launchway, set on the EM-carriage again, refueled and launched with next payload.

44 minutes ago, wumpus said:

Stratolaunch jet is more or less complete,

Imho, all stratolaunchers are a heresy*). Any separation at the hypersonic speed would likely cause a crash, and doesn't help too much.
Only SSTO, only hardcore. 

While, I believe, VTVL SSTO like BFR is the same heresy.
When you anyway have to put the payload on its top, why make it single-stage.

So, regular 10-40 t launches are by HTHL SSTO, while 500+ t launches are by VTVL TSTO.

*) Except the subsonic pegasus-carrier-like ones. They are handy for orbits with unusual inclinations and as a backup launchpad after a global nuke war (as they were designed)

 

P.S.
Certainly, I was thinking is it possible in KSP, not just irl.
It is. One needs KSPI-E, Kerbal Foundries, Kerbal Konstructs.

Edited by kerbiloid

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