Author Topic: Substantial Advantages to Equatorial Ramp Launch  (Read 11781 times)

Offline Admiral_Ritt

  • Member
  • Posts: 26
  • Liked: 6
  • Likes Given: 0
Substantial Advantages to Equatorial Ramp Launch
« on: 12/30/2015 04:17 pm »
 We know a few of the standard reasons to do this.

Near the Equator,  there is close to a 1,000 MPH free boost.
Near the Equator the atmosphere thins out faster due to Earth bulging distortion.
For Missions in the solar system orbital Plane,  No need to use extra fuel to maneuver you ship to this attitude.

Now there was/is a corporation that tried to take advantage of this, SEA LAUNCH.  but they were hampered by
bad engines that failed and went BOOM.  It did save something like  25% of the launch mass.  Which means
you could put a heavier payload to orbit OR  Put a heavier orbital insertion/maneuvering units to the stack.

But they were not ramp launched.   A ramp with a 3 : 1 slope is what I am proposing.
The ramp doesn't have to be built on a high mountain, but It can
be built in a handy accessible valley (probably in Ecuador).  The ramp would start with a strong downward
slope to get a few m/s from Earth's gravity.  about a 10 mile ramp is what I have in mind.  Below I will list the additional advantages.

1) you can use dumb Solid rockets to push a sled with a payload upfront.  They don't even need guidance.
2) If you ramp is sturdy enough you can pile on the solid boosters to move heavier payloads.
3) A solid booster abort.  There is a way to disable a solid rocket so is does not give net thrust(but will stay lit)
    The Space Shuttle could jettison burning SRB's but it was a risky maneuver.  Not so on a ramp.
4) You can recycle the booster casings, about 1/2 mile before leaving the ramp. You can use drag chutes
and brake friction to slow them down (after detaching from the orbital stack of course) 
5)  You can push your vehicle close to 3,000 Mph,  and be at say, 1 mile high. 

So you might say big deal 3,000mph that is not even close to final speed of 17,500 mph for low orbit.
But it is a very big deal.   It takes the Space shuttle stack more than 60% of it's fuel mass to reach this speed.
incidentally that is the speed It reaches when it's solid boosters detach.

It's a big deal also because you can make your orbital stack reusable.
That means there are no wasted components nothing gets thrown away.     

It not a panacea however:  Because:
1) The nose of your stack will need to be rugged and cover over the command module(equivalent) because of
the pressure and heat generated.  Nose cone can be ejected later.

2) The ramp would be unusable during rainy season.    which happens twice in the equatorial zones.  total
    loss of about 3 months, maybe a bit more.

3)  You might not retain control of It  as nations may change their minds and declare your ramp a national resource.

4) You have to transport the vehicle components to the equator. (there are some transport AC that specialize in this activity.

5)  Elon Musk just did something that MAY put he economics back in favor of boosters.  (by landing and reusing boosters)  But note they still have to examine the used engines and certify them to fly again They have to certify the fuel tanks and sensor suite too.(that can't be cheap).   With the Dumb solids in the ramp launch proposal you just use new dumb solids.

It's really a question of how much would it cost to build versus Dramatically lowering the costs of orbital launch.
If the rocket business goes into a fierce price war you might see movement toward this idea as competitors looks for any edge.
« Last Edit: 12/30/2015 04:20 pm by Admiral_Ritt »

Offline notsorandom

  • Full Member
  • ****
  • Posts: 1740
  • Ohio
  • Liked: 438
  • Likes Given: 91
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #1 on: 12/30/2015 05:12 pm »
One can determine rotational speed at a non equatorial latitude by taking the rotational speed at the equator and multiplying it by the cosine of the degree of latitude. Sea Launch gets the full boost from the equatorial latitude of 464m/s. KSC's has a latitude of 28.5o and thus gets a boost of 408m/s. The difference is only 56m/s. The reason why Sea Launch went to the trouble of launching at sea was because it was launching communications satellites destined for geostationary orbit. To get to that orbit a plane change maneuver needs to be done to reduce the orbital inclination to 0o. While the velocity boost gained over KSC was small the plane change maneuver was eliminated. The same rocket could deliver 17.5%-25% more payload because it didn't need to do that plane change maneuver.

Offline gbaikie

  • Full Member
  • ****
  • Posts: 1592
  • Liked: 49
  • Likes Given: 5
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #2 on: 12/30/2015 09:09 pm »
One can determine rotational speed at a non equatorial latitude by taking the rotational speed at the equator and multiplying it by the cosine of the degree of latitude. Sea Launch gets the full boost from the equatorial latitude of 464m/s. KSC's has a latitude of 28.5o and thus gets a boost of 408m/s. The difference is only 56m/s. The reason why Sea Launch went to the trouble of launching at sea was because it was launching communications satellites destined for geostationary orbit. To get to that orbit a plane change maneuver needs to be done to reduce the orbital inclination to 0o. While the velocity boost gained over KSC was small the plane change maneuver was eliminated. The same rocket could deliver 17.5%-25% more payload because it didn't need to do that plane change maneuver.

Yes. But in terms of a ramp [or whatever] adding something like 56m/s to the beginning of a rocket trajectory makes a significant difference. So the rotation speed isn't adding 56m/s to the beginning of a rocket trajectory rather it's subtracting from the final velocity needed.
Or a ramp [or whatever] added velocity would be relative to the atmosphere, gets you to higher elevation quicker  and is mostly relevant to the gravity loss that a rocket would otherwise have.

One problem of the 3000 mph ramp speed is the rocket is being send in the wrong direction, or it would be better if it was going nearly vertical. Or I would say 500 mph going vertical would as good [comparable/better] as 3000 mph going at less than 30 degree.

A problem with a mountain is related to the down range, or an advantage not mentioned with a sea launch is the down range can be ocean. If surrounded by ocean with nothing in launch range vulnerable to the explosive blast of rocket failure, there is no need to having a rocket capability of self destruct. The rocket might explode, but you don't need to make the decision to make it explode before the uncontrollable rocket reaches something it can damage.
« Last Edit: 12/30/2015 09:16 pm by gbaikie »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37440
  • Cape Canaveral Spaceport
  • Liked: 21450
  • Likes Given: 428
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #3 on: 12/31/2015 01:36 am »

It's really a question of how much would it cost to build versus Dramatically lowering the costs of orbital launch.
If the rocket business goes into a fierce price war you might see movement toward this idea as competitors looks for any edge.


The disadvantages greatly outweigh the minimal advantages.  In fact, the ramp has no advantages.

Offline Hotblack Desiato

  • Full Member
  • ***
  • Posts: 369
  • Austria
  • Liked: 74
  • Likes Given: 52
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #4 on: 01/01/2016 10:07 am »
One can determine rotational speed at a non equatorial latitude by taking the rotational speed at the equator and multiplying it by the cosine of the degree of latitude. Sea Launch gets the full boost from the equatorial latitude of 464m/s. KSC's has a latitude of 28.5o and thus gets a boost of 408m/s. The difference is only 56m/s. The reason why Sea Launch went to the trouble of launching at sea was because it was launching communications satellites destined for geostationary orbit. To get to that orbit a plane change maneuver needs to be done to reduce the orbital inclination to 0o. While the velocity boost gained over KSC was small the plane change maneuver was eliminated. The same rocket could deliver 17.5%-25% more payload because it didn't need to do that plane change maneuver.

Compared with that, the CSG (Centre Spatial Guyanais) sits at 5° north, and has a boost of 460m/s. It's just 4 m/s short of being perfect, without the hassle of launching stuff off from an oil rig. That's why the russians were interested in getting a soyuz-launchsite over there.


If a launch sled helps that much, I don't know. But somebody should be able to calculate it. In theory, it should be possible to get a rocket on a sled to pretty high speeds.

Offline indaco1

  • Full Member
  • **
  • Posts: 283
  • Liked: 64
  • Likes Given: 37
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #5 on: 01/02/2016 07:20 pm »
It helps if the veichle is optimized for assisted launch.

A slightly lower thrust to mass is allowed (that enables a slightly better mass ratio) and lighter booster engines with lower sea level and better vacuum isp are also allowed.

To extimate the gain a trajectory optimizator is not enough, you have also to redesign the veichle.
Non-native English speaker and non-expert, be patient.

Online Prettz

  • Full Member
  • ****
  • Posts: 497
  • O'Neillian
  • Atlanta, GA
  • Liked: 259
  • Likes Given: 30
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #6 on: 01/02/2016 07:25 pm »
Does this help reduce the cost of access to space by an order of magnitude?

Offline gbaikie

  • Full Member
  • ****
  • Posts: 1592
  • Liked: 49
  • Likes Given: 5
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #7 on: 01/02/2016 08:43 pm »
Does this help reduce the cost of access to space by an order of magnitude?

Does it increase payload by 10 times or reduce cost to 1/10th to orbit?
I don't think so.
But it could half the mass of rocket with a sub-orbital- trajectory or double the payload.

In terms of orbital or Earth escape, it could increase payload by around 20%.
Or equatorial and boost vs 28 inclination and no boost, one could increase the payload to GEO by about 50%.

Edit: There is a way to lower chemical rocket launch cost by order of magnitude and that could be unrelated to a "Equatorial Ramp Launch".
And in simple terms it involves a higher launch rate per year and doing stuff like what SpaceX is doing
in terms of reusing it's first stage and it's Falcon Heavy.
And anything like a "Equatorial Ramp Launch" requires a high yearly launch rate. High launch rate being say, 20 or more launches per pad or "ramp" per year.
Or say 20 Heavy Falcon launched per year [can be from a number of pads] and their first stages being reused would be getting fairly close to order of magnitude reduction of costs/price.
« Last Edit: 01/02/2016 10:05 pm by gbaikie »

Offline mikelepage

  • Full Member
  • ****
  • Posts: 1218
  • ExodusSpaceSystems.com
  • Perth, Australia
  • Liked: 855
  • Likes Given: 1358
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #8 on: 01/04/2016 03:31 am »
Considering the logistical nightmare it would take to build this thing (I'm assuming you've never been to Ecuador :) ) there's no way the (relatively) minor reduction of energy expenditure would make it worth it.

I mean, even before you get to the socio-economic issues of that part of South America, or the high levels of resentment the local peoples have towards westerners (particularly Americans) coming in and building mega-projects which have little or no tangible benefit to the population, you'd be launching over one of the most pristine parts of the Amazon, and since the wet season often causes mudslides on the mountains, you'd need to drive your foundations deep into the side of potentially active stratovolcano (I suppose that means a volcano lair is an option).  In short, not happening.

I have been a fan of near-equatorial launch sites however, mainly because they are by far the easiest way of reaching equatorial LEO and the low radiation environment that exists there. 

The best candidate for that is probably French Guiana where the main ESA Kourou launch site is already in frequent use, and the port there is set up to move rockets, and the locals are actually proud of it.  There aren't any mountains in the vicinity, however.

Offline notsorandom

  • Full Member
  • ****
  • Posts: 1740
  • Ohio
  • Liked: 438
  • Likes Given: 91
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #9 on: 01/04/2016 05:35 pm »
Compared with that, the CSG (Centre Spatial Guyanais) sits at 5° north, and has a boost of 460m/s. It's just 4 m/s short of being perfect, without the hassle of launching stuff off from an oil rig. That's why the russians were interested in getting a soyuz-launchsite over there.
The Russians do have a much more tricky time of it having to launch from Baikonur into a 51.6 degree inclination. One can see how the difference between CSG and Baikonur is great enough that it becomes worth it to build another launch pad there (especially for GTO missions). However the difference between CSG and KSC is not nearly as much so it is likely easier to just build a slightly bigger rocket or a slightly smaller payload rather than build facilities at CSG.

Baikonur is actually 45.9 degrees north but the higher inclination is needed to prevent spent stages from falling in certain areas. But that brings up another important point. We are comparing launch site inclination using a low orbit of the lowest inclination a launch site can do. As the inclination increases the benefit from a lower latitude launch site decreases. For example when comparing a launch to the ISS at 51.6 degrees the difference between KSC and CSG is very little. Also an immovable ramp can launch to just one inclination.

Offline indaco1

  • Full Member
  • **
  • Posts: 283
  • Liked: 64
  • Likes Given: 37
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #10 on: 01/04/2016 05:57 pm »
Considering the logistical nightmare it would take to build this thing (I'm assuming you've never been to Ecuador :) )

I think that if something similar to this will be attempted it could be not Equador and it could be not so equatorial.

It could be Mauna Kea, instead, sharing some of the facilities with MKO, including the road.  Just small launchers that can be transported in parts by truck.  Orbits will be very interoperable with KSC (same latitude), no assist, ramps and catapults initially,  just a traditional launch pad but engines optimized for high altitude launch. Other reasons because Mauna Kea could be better are obvious.

Besides economics that probably don't justify the extra cost (but it's worth some calculation) there's a reason because it can't be done: range safety.  But this is true for Ecuador, also...  A launch pad has to be by the ocean or in a very desert desert, period.
Non-native English speaker and non-expert, be patient.

Offline dchill

  • Full Member
  • *
  • Posts: 116
  • Liked: 39
  • Likes Given: 4
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #11 on: 01/04/2016 06:07 pm »
As far as possible locations, Mt. Chimborazo in Ecuador has only been discussed on these forums at least 42 times before:
<<https://www.google.com/#q=Chimborazo+site:nasaspaceflight.com>>

Offline indaco1

  • Full Member
  • **
  • Posts: 283
  • Liked: 64
  • Likes Given: 37
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #12 on: 01/04/2016 06:42 pm »
^^ I remember some of them, but Chimborazo is not that better than Mauna Kea for performances, but it's much worst for facilities, logistics and politics.

Altitude is 6200 instead of 4200, but it's a rocky and step peak, it's unreasonable to arrive to the top with a road, maybe a little lower quote is more reasonable.  Mauna Kea already has a road to the very top and many useful facilities.   

Now, just check air density wwith this standard atmosphere calculator:

http://www.digitaldutch.com/atmoscalc/

Sea level:  1.22500
Mauna Kea (4200m): 0.801981
Chimborazo reasonable (5200m): 0.720317
Chimborazo unreasonable (6200m): 0.645172

Others in this thread have explained that be closer to the equator doesn't give that gain.

Do you think that a 0.15 gain in air density and the lower latitude are worth the problems you'll have with Chimborazo?
Non-native English speaker and non-expert, be patient.

Offline Admiral_Ritt

  • Member
  • Posts: 26
  • Liked: 6
  • Likes Given: 0
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #13 on: 01/04/2016 11:01 pm »
    I never suggested this be done in a high mountain.
THAT, would be expensive and not worth it IMO because of the logistics of
building the Ramp, and bringing the vehicle components to the site.

I suggested a lower valley,  at most 1km high so that costs to
build and operate are low.

The savings from this approach are as I stated before.

DUMB, solid boosters, Lots of them.  No guidance required.
An initial Downward slope to give the rocket inertia.
Equatorial Launch bonus, both to orbit and orbiting the plane of the solar system.
Atmosphere thins faster at the equator due to equatorial  bulge.
Used Boosters can braked before leaving ramp so that they don't land on a adjoining landscape/country.

Unfortunately I think about 3,000 MPH is the maximum feasible launch speed due to still thick atmosphere.
And I don't think it's worth it to building a ramp 5-6 KM high,  in some god forsaken peak, just to get
to maybe 5,000MPH.


Offline 1

  • Full Member
  • ***
  • Posts: 367
  • El Segundo, CA
  • Liked: 749
  • Likes Given: 10
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #14 on: 01/05/2016 03:01 am »
In fact, the ramp has no advantages.

Not true! Run in reverse, it would make a fantastic ski jump.

Offline mikelepage

  • Full Member
  • ****
  • Posts: 1218
  • ExodusSpaceSystems.com
  • Perth, Australia
  • Liked: 855
  • Likes Given: 1358
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #15 on: 01/05/2016 11:07 am »
   I never suggested this be done in a high mountain.THAT, would be expensive and not worth it IMO because of the logistics of
building the Ramp, and bringing the vehicle components to the site.

I suggested a lower valley,  at most 1km high so that costs to
build and operate are low.

The savings from this approach are as I stated before.

DUMB, solid boosters, Lots of them.  No guidance required.
An initial Downward slope to give the rocket inertia.
Equatorial Launch bonus, both to orbit and orbiting the plane of the solar system.
Atmosphere thins faster at the equator due to equatorial  bulge.
Used Boosters can braked before leaving ramp so that they don't land on a adjoining landscape/country.

Unfortunately I think about 3,000 MPH is the maximum feasible launch speed due to still thick atmosphere.
And I don't think it's worth it to building a ramp 5-6 KM high,  in some god forsaken peak, just to get
to maybe 5,000MPH.

Emphasis mine.  I see where the misunderstanding is now - you're assuming the ramp would save fuel if you can get your vehicle to 3000MPH (because the shuttle had spent 60% of its fuel to get to 3000MPH) - but the problem is that unless you are at the same altitude as the shuttle was when it was doing 3000MPH (~30 Miles or so) then the air friction of the lower atmosphere will wipe out most of that saving.

This thread is actually quite similar in concept to the railgun launcher concepts that have been before, and the problem is that they all need to be built on top of a tallest mountain you can find to even have a chance of working (hence all the logistical problems of finding high mountains on the equator).  Thing is, even if you built this on top of Everest you would still be way below the kind of speeds that might make it worthwhile.

What might work however is if you build a hyperloop style railgun (on a ramp) that launches things into suborbital trajectories (say at 2 km/s up to 200km) and have a space tether in a high elliptical orbit that comes past at the right moment and pulls it into orbit.  If it's a rocket-less craft, you might even get away with building such a megaproject above a rainforest.

Offline Burninate

  • Full Member
  • ****
  • Posts: 1145
  • Liked: 360
  • Likes Given: 74
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #16 on: 01/05/2016 11:55 am »
Emphasis mine.  I see where the misunderstanding is now - you're assuming the ramp would save fuel if you can get your vehicle to 3000MPH (because the shuttle had spent 60% of its fuel to get to 3000MPH) - but the problem is that unless you are at the same altitude as the shuttle was when it was doing 3000MPH (~30 Miles or so) then the air friction of the lower atmosphere will wipe out most of that saving.


As I understand the proposal, that's not the problem.  The problem is that dumb, solid boosters cost just the same whether they're on an incline or vertical;  They're going to pitch over shortly after launch anyway in a conventional launch.  There is little actual savings.  At best, you save a tiny bit of dV on gravity losses, about equivalent to how long it stays on the track multiplied by 9.8m/s^2... but as you mention, then you pay for that in air resistance.

It doesn't actually help to build it on Everest, because you're still paying rocket prices for your dV.  You need some other mode of propelling the rocket along a track, for a track to be worthwhile (and you're not going to get much from an initial decline with a gravity drop, unless you start out at the opposite mountain range).  Several proposals for impulsive methods exist: linear electromagnetic motors, light gas guns, air-breathing first stages, ram accelerators.  All of the above seem fairly feasible, so long as a customer could be found who will pay for thousands of tons of high-G cargo launched per year.
« Last Edit: 01/05/2016 11:57 am by Burninate »

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3024
  • Liked: 543
  • Likes Given: 604
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #17 on: 01/05/2016 12:07 pm »

Near the Equator the atmosphere thins out faster due to Earth bulging distortion.

No, it does not.

Quote
For Missions in the solar system orbital Plane,  No need to use extra fuel to maneuver you ship to this attitude.

I think you are wrong on this too. The advantage is if you launch stuff to equatorial *Earth* orbit.

Quote
But they were not ramp launched.   A ramp with a 3 : 1 slope is what I am proposing.

This was discussed over the decades over and over and over. It's not worth it.

Solid rocket motor reuse, money-wise, did not work too well e.g. for Shuttle. Definitely not a gas-n-go exercise.

Solid motor aborts are not demonstrated and while they may be possible, they are likely problematic for the rocket, payload, and ramp.

Without abort capability, you must lit your LV booster engines when you already committed to launch. No hold-down. Check out how often todays launches are aborting in the last ~30 seconds. It is not too uncommon - and this happens on a stationary rocket, not on a rocket riding a multi-g sled!

Ramp and sled need maintenance. They aren't trivial pieces of equipment.

For US customers, launch for US soil is easier for logistical, language, and paperwork reasons. That's one of the reasons why customers will jump Proton in favor of SpaceX, even while SpaceX prices are not substantially lower than Proton's.

This boils down to:

At best, The Ramp allows you to cut your LV size by 20-30% size. In which case, you could just design it to be 20-30% bigger from the start, and not torture yourself with all the added hassle.
« Last Edit: 01/05/2016 12:07 pm by gospacex »

Offline Admiral_Ritt

  • Member
  • Posts: 26
  • Liked: 6
  • Likes Given: 0
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #18 on: 01/05/2016 03:12 pm »
   You are correct, Mr GoSpaceX
 RE equatorial atmosphere,  the atmosphere is taller, but less dense, so it's a wash out.  I did read that Incorrect information somewhere, I did not pull it out my hat.

Equatorial orbital insertion are the majority of non-military launches. 

If solid boosters are expensive, why not an efficient Jet engine stack to drive the stack
to 1800MPH,  Then use Solids,  (You would certainly need fewer solid boosters) to bring
yourself to about 3,000MPH.  (yes I know I changed the composition of the vehicle so do not
scream it back at me.)   It is true that the jet engines would have to drag their own fuel, and push
the solids it will use in the assist off the ramp.

But you are correct, MR goSpacex in the END.  Is it cheaper?

  Not even Sea Launch thought so, or they would have propositioned some Equatorial nation to build a scaled down version of the 10 mi ramp.  Even an additional 2,000MPH is nothing to sneeze at.



Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37440
  • Cape Canaveral Spaceport
  • Liked: 21450
  • Likes Given: 428
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #19 on: 01/05/2016 03:36 pm »
Equatorial orbital insertion are the majority of non-military launches. 


Not true.  Weather, mapping, comm, science etc used other orbits.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37440
  • Cape Canaveral Spaceport
  • Liked: 21450
  • Likes Given: 428
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #20 on: 01/05/2016 03:37 pm »

  Not even Sea Launch thought so, or they would have propositioned some Equatorial nation to build a scaled down version of the 10 mi ramp.  Even an additional 2,000MPH is nothing to sneeze at.



Cheaper to build a bigger rocket and fly from Florida or Texas than to build and use a ramp and solid rockets.  Also, the rocket that uses the ramp and sled would be heavier since it would have to lay on its side on the sled and take the lateral loads.

And so again,  there are no "savings" and hence will be no movement towards this.

I need to quote an early post.  There are no advantages.
« Last Edit: 01/05/2016 03:45 pm by Jim »

Offline Admiral_Ritt

  • Member
  • Posts: 26
  • Liked: 6
  • Likes Given: 0
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #21 on: 01/05/2016 04:16 pm »
 
Jim, Regarding equatorial insertion, which is required for geostationary satellites.

 go look at this site http://www.orbiter-forum.com/showthread.php?t=26464
Remove all the PLA, Russian, and US Military.  Do you see a majority of launches being
weather and deep space launches?  I don't.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37440
  • Cape Canaveral Spaceport
  • Liked: 21450
  • Likes Given: 428
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #22 on: 01/05/2016 04:42 pm »

Jim, Regarding equatorial insertion, which is required for geostationary satellites.

 go look at this site http://www.orbiter-forum.com/showthread.php?t=26464
Remove all the PLA, Russian, and US Military.  Do you see a majority of launches being
weather and deep space launches?  I don't.

Look at 2015.  I only see 16 or commercial GSO missions.   I see 30 or so ISS missions, Orbcomm, MMS, SMAP, DSCOVR, Galileo, etc missions.

Offline Admiral_Ritt

  • Member
  • Posts: 26
  • Liked: 6
  • Likes Given: 0
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #23 on: 01/05/2016 10:29 pm »
 Fine, GeoSych Sats are a minor business.

  What is surprising to find when you do a cost per Delta V capacity is that Boosters are not that
cheap at all.   This is surprising to me.  This is because a liquid fuel LOX rocket has to be replaced with about 2 Solid fuels rockets to get the same total lift capacity, negating the cost savings.   But still Liquid rockets are more complex and less reliable.
   This is why I though the Solid would do better  Ramp Launched,  You don't really need to reinforce much as in a rocket with LOX tanks. But cost reduction is not significant.
    Maybe a better question is, are solid rockets overpriced?  maybe because the only alternative
is Liquid fuel rockets and there is not a 3rd option.
« Last Edit: 01/05/2016 10:31 pm by Admiral_Ritt »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37440
  • Cape Canaveral Spaceport
  • Liked: 21450
  • Likes Given: 428
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #24 on: 01/05/2016 11:16 pm »
  But still Liquid rockets are more complex and less reliable.
   

Not true for new solid motors
« Last Edit: 01/05/2016 11:17 pm by Jim »

Offline indaco1

  • Full Member
  • **
  • Posts: 283
  • Liked: 64
  • Likes Given: 37
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #25 on: 01/06/2016 12:14 am »
A launch assist could be a game changer is if it enables a reusable quasi-SSTO, eg. expendable dumb tank, rest of the veichle reusable with minimal refurbishment and low turnaround time, say just thermal shield replacement and add a new refuelled tank.   This has to use liquid engines, of course.

Any reasonable assist, including high quote ramps and air launch, will probably not be enough to achieve this or simply there's not the request for the high number of launches required to justify the huge r&d, investments and fixed costs.


Non-native English speaker and non-expert, be patient.

Offline Burninate

  • Full Member
  • ****
  • Posts: 1145
  • Liked: 360
  • Likes Given: 74
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #26 on: 01/06/2016 12:39 am »
OP is making a lot of highly speculative statements here about vague approaches to tackle a problem that has been explored exhaustively for half a century without the economic problems ever working out.  The thing is, it's basically just been 90% solved, two weeks ago.  SpaceX has reusable first stages now.  If you can make a reusable first stage, or a reusable first stage plus reusable middle stage, then any of the purported benefits of a 9-10km/s SSTO can be realized with a 3km/s or 6km/s upper stage to orbit, with a fraction of the engineering diffuculties, and no need for megastructures.

Several proposals for impulsive methods exist: linear electromagnetic motors, light gas guns, air-breathing first stages, ram accelerators.  All of the above seem fairly feasible, so long as a customer could be found who will pay for thousands of tons of high-G cargo launched per year.

All of these and more have been investigated by thousands of people in detailed engineering studies over the years.
« Last Edit: 01/06/2016 12:43 am by Burninate »

Offline Burninate

  • Full Member
  • ****
  • Posts: 1145
  • Liked: 360
  • Likes Given: 74
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #27 on: 01/06/2016 12:54 am »

    Maybe a better question is, are solid rockets overpriced?  maybe because the only alternative
is Liquid fuel rockets and there is not a 3rd option.

Solid rockets require precision formulation, even mixing, and molding of solid/plastic mixtures of live explosives.  They're great for weapons of war because they can be fired off at short notice without fueling, but the bulk propellant is much, much more expensive than RP-1/LOX, and the safety & handling requirements are much stiffer.  It also apparently creates a need (necessarily?  unsure) for vertical integration, which requires a pricy construction bay.

Is it more expensive than throwing away an entire RP-1/LOX engine every time you launch?  We can say conclusively: Sometimes.  The prices are comparable for a first stage.  If they weren't, either liquids or solids would rule the industry, but they coexist in fact, with 'strap-on boosters' being very common for the first phase of flight where low Isp hurts least.  Solids also have an implicit subsidy from their history and R&D expenditures as strategic weapons.

Is it more expensive than a reusable RP-1/LOX first stage?  Probably not.
« Last Edit: 01/06/2016 12:56 am by Burninate »

Offline Nilof

  • Full Member
  • ****
  • Posts: 1177
  • Liked: 597
  • Likes Given: 707
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #28 on: 01/06/2016 02:10 am »
Main issue with solids imho is the need for completely different engineer skillsets, manufacturing techniques, handling, and production facilities. Since most of the cost of launch is ultimately fixed costs related to this infrastructure, and since all-liquid is clearly better than all-solid; the only reason to use them is if you are required to make them for other reasons than space launch and can get them at subsidized prices. Otherwise, LRB's like on the R7 family that have commonality with the center stage make more sense economically.

Of course, if keeping infrastructure costs down isn't a priority or actively discouraged for political reasons, solids can have a great performance with decent Isp and optimal thrust at all times.
« Last Edit: 01/06/2016 02:12 am by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline gbaikie

  • Full Member
  • ****
  • Posts: 1592
  • Liked: 49
  • Likes Given: 5
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #29 on: 01/06/2016 07:36 pm »
A launch assist could be a game changer is if it enables a reusable quasi-SSTO, eg. expendable dumb tank, rest of the veichle reusable with minimal refurbishment and low turnaround time, say just thermal shield replacement and add a new refuelled tank.   This has to use liquid engines, of course.

Any reasonable assist, including high quote ramps and air launch, will probably not be enough to achieve this or simply there's not the request for the high number of launches required to justify the huge r&d, investments and fixed costs.

I agree.
I would say once we have more rocket launches per year [globally] this will create a market for launch assist. But this includes sub-orbital launches. And the increases in launch could happen soonest with the sub-orbital market.
Another direction of increased launch could be possible were NASA to explore the Moon to determine if and where there were commercially minable lunar water. Which basically means find region in polar region of the Moon which are about 1 square km and have about 100,000 tons of minable water within 1 meter depth, but instead of just water, the 100,000 tons it could include other volatiles: CO, CO2, CH4, H2, etc.
And a mixture volatiles in addition to water could make a mining location more minable- and of course many other factors can make an area more minable.

Another way of getting more launches is cheaper launch prices and getting a launch quicker is also related to cheaper launches- or one could call this more access to more people to space.

I think with assisted launch the cost of rocket fuel for the entire launch is important, so generally that argues against "dumb" solids but could include "dumb" reusable liquids. And solids could have "environmental issue" particularly with many launches.
« Last Edit: 01/06/2016 07:54 pm by gbaikie »

Offline JasonAW3

  • Senior Member
  • *****
  • Posts: 2443
  • Claremore, Ok.
  • Liked: 410
  • Likes Given: 14
Re: Substantial Advantages to Equatorial Ramp Launch
« Reply #30 on: 01/06/2016 09:12 pm »
  But still Liquid rockets are more complex and less reliable.
   

Not true for new solid motors

Solid/liquid hybrid rockets have a lot of potentile as well, but they seem to need much more development before they are ready to be a primary booster system.
My God!  It's full of universes!

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1