Author Topic: Mountain Launch System  (Read 7069 times)

Offline Iikka Keranen

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Re: Mountain Launch System
« Reply #20 on: 10/09/2009 07:57 PM »
Right, the concept isn't new. It ultimately goes back to Jules Verne.

I was thinking a bit more about the "lid" issue. The tube door will need to be heavy in order to survive the pressure, so it physically cannot be opened instantaneously or by the direct impact of the rocket against it. A possible solution would be to only partially evacuate the tube, causing the air pressure to build up in front of the launch platform as it approaches the door. The door would be designed to be held shut by the pressure differential, and passively pop open when the pressure inside matches that of the outside. The system would be tuned so that this happens when the rocket is traveling the last few hundred feet of the tube. If the launch platform has a good enough seal against the walls of the tube, this will also allow using gas pressure to drive it instead of counterweights.

The reason to use a mountain rather than a building would be cost. A kilometer tall building is more expensive than a kilometer deep shaft, and buildings don't scale much higher than that. There is a vertical shaft in a mine in South Africa that's just a hair short of 3km while the current record for a building height is 818m. Longer length of the launch tube translates to either higher launch speed, or lower acceleration which are both desirable.

Offline MLSman

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Re: Mountain Launch System
« Reply #21 on: 10/09/2009 08:37 PM »
Regarding to comments on business case for the MLS system, I agree it woulld not be justified.  When I mentioned Sea Launch I was referring to the technical success and am aware of their bankruptcy.  But I think the business evaluation is secondary to the technical evaluation.  In my mind it comes down to an equation, unfortunately it is an equation I don't know how to solve.  I'm hoping there is someone on this site that can answer this.  Here is the problem:
  According to the text I have (Wertz) the Atlas IIAS payload to LEO is 8560 & GEO is 3460 from the Eastern test range.  Similarly for Ariane 44L payload to LEO is 9600 and GEO is 4200.  I don't know if the Atlas numbers include a plane change manuever.  But the question is what would be the increase in payload capicty given the MLS paremeters of 500 mph initial speed, 17,000 altitude, and the corresponding aerodynamic drag reduction.  Hopefully someone has a model that churn out an answer.
  I would appreciate anybody that can help with this to see if the idea merits further work.
Thanks,
MLSman
 

Offline hop

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Re: Mountain Launch System
« Reply #22 on: 10/09/2009 11:46 PM »
But I think the business evaluation is secondary to the technical evaluation.
No, it isn't secondary. If the cost of your scheme is greater than the cost upgrading existing launch vehicles to have the same capacity (which it almost certainly is at anything close to current launch rates), then everything else is irrelevant.

We can estimate (by looking at the cost of things like long railroad tunnels and other launch site projects) that your scheme will cost at least several billion just to set up. This would buy substantial upgrades on any existing LV. Furthermore, since your scheme involves launching existing rockets, and is undeniably more complex than existing fixed pads, we can say with high confidence that no reduction in per launch cost will take place. At best, you would get slightly increased payload for the same cost.

Quote
According to the text I have (Wertz) the Atlas IIAS payload to LEO is 8560 & GEO is 3460 from the Eastern test range.  Similarly for Ariane 44L payload to LEO is 9600 and GEO is 4200
Note that these vehicles are retired.

Quote
But the question is what would be the increase in payload capicty given the MLS paremeters of 500 mph initial speed, 17,000 altitude, and the corresponding aerodynamic drag reduction.  Hopefully someone has a model that churn out an answer
Do your own homework. You should easily be able to find sufficient information on the internet to get a BOTE estimate.

Offline Lab Lemming

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Re: Mountain Launch System
« Reply #23 on: 10/10/2009 04:33 AM »
At the risk of getting off-topic, would launching Ares-I from a 10.000 foot site lower the max-Q appreciably (as you'd go trans-sonic in much thinner air)?  If the USAF won't certify a Canaveral launch, maybe they should shop around the high altitude equatorial countries...

Offline mrhuggy

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Re: Mountain Launch System
« Reply #24 on: 10/10/2009 07:04 PM »
At the risk of getting off-topic, would launching Ares-I from a 10.000 foot site lower the max-Q appreciably (as you'd go trans-sonic in much thinner air)?  If the USAF won't certify a Canaveral launch, maybe they should shop around the high altitude equatorial countries...

No need really, Monu Kea Hawaii

Offline Lab Lemming

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Re: Mountain Launch System
« Reply #25 on: 10/13/2009 02:57 AM »
Oh sure, vibrations aren't bad for telescopes...

At the risk of getting off-topic, would launching Ares-I from a 10.000 foot site lower the max-Q appreciably (as you'd go trans-sonic in much thinner air)?  If the USAF won't certify a Canaveral launch, maybe they should shop around the high altitude equatorial countries...

No need really, Monu Kea Hawaii

Offline khallow

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Re: Mountain Launch System
« Reply #26 on: 10/13/2009 03:09 AM »
Oh sure, vibrations aren't bad for telescopes...

If telescopes can't coexist, we can always move the telescopes or the launch system. Depends what's more important.
Karl Hallowell

Offline hop

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Re: Mountain Launch System
« Reply #27 on: 10/13/2009 04:40 AM »
If telescopes can't coexist, we can always move the telescopes or the launch system. Depends what's more important.
Somewhat more seriously, the logistics of operating from a mountain top would be rather challenging and expensive. Good luck getting the crawler-transporter up that road to Mauna Kea ;)

Offline blazotron

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Re: Mountain Launch System
« Reply #28 on: 10/13/2009 05:05 AM »
Remember that any vertical velocity eventually goes into altitude, since once you reach orbit your vertical velocity is zero.  So, an extra 500 mph is roughly equivalent to launching the rocket from about 8000 ft higher (total of 25000 ft) at zero velocity.  This does not account for the air resistance, but that will be something on the order of a 10% effect.  In any event, you still have to pump the enormous horizontal velocity into the payload to achieve orbit. 

Maybe you can rig orbiter to launch from such an altitude to get the performance answers you want (I don't actually know its capability as I have not played with it before)?

Offline renclod

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Re: Mountain Launch System
« Reply #29 on: 10/13/2009 08:02 AM »
...
One of the largest advantages of the MLS concept is that it would be designed to use all of the existing launch vehicles as is.
...

Existing liquid fuel boosters (first stages) generaly ignite at zero velocity, in a hold-down posture, so as to be able to abort the launch if an engine malfunctions (see Falcon 1 in recent years).

Obviously at 500mph the vehicle is committed and the hold-down procedure doesn't makes sense any more.

The other launch vehicles not using hold-down have solid rocket first stages.

----------------

Another interesting issue is what kind of vibrations would be induced in a 10,000 ft long, 1 inch dia wire rope turning a ?ft dia wheel at 400-500mph. What is the world record speed (linear) for 100s tons pulleys ?

« Last Edit: 10/13/2009 08:12 AM by renclod »

Offline JohnFornaro

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Re: Mountain Launch System
« Reply #30 on: 10/16/2009 01:32 PM »
Here, here, AlexinOK.  I too, was glad to read Jim's first remarks, for one.  The neutral tone is greatly appreciated by me and enhances the discussion.

A lotta people have toyed with various schemes of launch assist.  I was one of many who suggested a MagLev rail as a possible first stage, per:

http://forum.nasaspaceflight.com/index.php?topic=16553.0

Having done some of the math, I was surprised to find that a 500 to 1000 mph assist, while helpful, was overcome by the substantial costs of the infrastructure which would have to be constructed.

I think a technical evaluation should take place on the first envelope.  As a goofy example, compressed hummingbird wings may not prove to be a feasible fairing structure at the forces expected.  I disagree with hop only slightly.  The second envelope should address the "business evaluation".

Also, it's good to see Mt. Chimborazo considered again.  Yet another quibble, in my style of elocution.  MLS is the Multiple Listing Service.  Choose another acronym.

I did review your patent award however.
Sometimes I just flat out don't get it.

Offline fatjohn1408

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Re: Mountain Launch System
« Reply #31 on: 02/28/2011 04:34 PM »
hello,

I've been playing with the idea of mountain launch for a while now. Now that i've read your report I would say ditch the vacuum part. Just coat the fairing with a bit of ablative material and you'll be fine.
Secondly, ditch the 10,000+ feet requirement of the counterweight tunnel. Make it 500 and replace the force of gravity by the magnetic force by making the counterweight to act like a maglevtrain and the tunnel to act like a maglev rail. Provide a pulley system that the counterweight/maglevtrain needs to move only 1 feet for every 20,30,50 feet (you name it) that the rocket needs to move.
Third ditch the rocket tunnel, place it roughly on the mountain slope since if you eject at a certain altitude and speed a vertical position is not preferred. That's why the M-V was tilted during launch, went too fast too quickly.
Fourth change mt chimborazzo to mt Huyani potosi. A nice mountain with a plateau in front of it.

Thoughts?

Offline baldusi

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Re: Mountain Launch System
« Reply #32 on: 02/28/2011 05:37 PM »
You can brake the counterweights by simply narrowing the tunnel. This will  create an overpressure and do a pneumatic brake. In fact, you could put vacuum only on the counterweight tubes and connect them to the main tube, they will also work as pneumatic pumps (since the counterweight will pull the air).
In any case, you should consider what's the cost of installing a new launch site, of making a four lane, road to the top o a mountain and rated for a million tonnes vehicles. You can look up the cost of making a subway (15M to 30M per km). It should be way higher than that. Think that current boring machines are designed to work in horizontal. If you want to go vertical you can't remove the debris fast enough for what the boring machine can do. But that's not the most important part. The most important part is the development effort. Are you aware of the cost of design, validation and qualification of a normal pad? That's with basically known technology. Here you have to start from zero.
You might also want to use a magnetic system that give you around 4G. With a 3.3km tube (that's close to 10k feet), you'd have 510m/s of delta v. Which is about a 5% of the total necessary delta v. Doing a quick number, this would add about 18% of payload (Rocket Equation with ISP of 305s, single stage, and 3.5% payload fraction initially, and assuming 10,000m/s of delta v necessary to reach LEO).
Again, an 18% increase in payload is less than you get from using a single SRB in an Atlas V or Delta IV. In other words, you have to think how many SRB are you spending on research and development just to get there. I don't have the number right now but I estimate that's some 6 to 8 are spent on EELV per year.

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