NASA Engineers Propose Combining a Rail Gun and a Scramjet to Fire Spacecraft Into Orbit

why don't they just mount this rail gun on the side of a mountain near a nuclear power plant, make it 10-15 miles long, and curve the last 3 miles at the end so that it shoots strait up, and skip the whole scramjet stage.

I believe this is how Dr. Heywood R. Floyd was delivered to the Space Station at the begininning of the book, 2001: A Space Odyssey.

@VoodooX i was thinking the same think, or one coming from underground just like intercontinental missiles? As long as its pointing straight up. I think maybe this is the proposed plan because they get kickbacks from the manufacturers of these scramjets. its all about $

With their country led by engineers as opposed to the West where nearly all our leaders are attorneys, China has a much better idea for a cheap launch system.

The Chinese could care less about greenies, so a modification of Freeman Dyson's Orion scheme is in the works to give them all the lift capacity for which anybody could ever envision a need.

Build a 2 mile long pipeline and sink it in the ocean two miles deep. Put a small nuke at the bottom in a put a thick steel plate underneath an automated payload capsule. Light the nuke and let er rip. When the projectile exits slam the door shut and redirect the radioactive steam into the water. Radiation leaks - a lot less than the daily radioactive output of one of their coal plants.

3000 tons at $10 a lb straight to the moon.

Great for compressibles like ice, steel,frozen food,fuel tanks, rocket fuel, circuit boards, nuclear fuel, copper wire and a thousand other commodities needed in space.

Humans and flower petals will have to be launched another way.

http://nextbigfuture.com/2010/12/sea-based-launch-option-for-nuclear.html

With the cargo capacity available, a simple very efficient space based transport could use the nuclear engines from stolen NASA Nerva designs since we aren't allowed to use them.

You're worried about a conspiracy by ... Big Scramjets. Yes.

No, the *point* is the scramjet itself. Launch something out of a rail gun and it will steadily decelerate due to gravity and resistance. It doesn't get you anywhere; it's a Wile. E. Coyote approach to space.

A scramjet can reach escape velocity before it runs out of air on the way up. The reason that they're using a rail gun here to launch it - and they could just as easily call it a mag-lev - is because scramjets can't operate below supersonic speeds. Ordinarily they have to be launched from other jets, rockets, etc. The rail gun removes that problem. But the scramjet is still doing all the heavy lifting once it gets started.

So here's ... my question. How exactly do you put *people*, which the article *specifically mentions*, on a device that accelerates to Mach 1 in *two miles*?

@VoodooX While it's counter-intuitive, you need more horizontal speed to stay in orbit rather than just climbing straight up. The space shuttle and other rockets only climb straight up for about a minute before tipping themselves over. Also, it'll let the Scramjet produce some lift which'll translate to more payload.

build it up the side of a MOUNTAIN. Without snow on top of it there are plenty out in california by 29 palms that i thought would work out great. about a mile high with some consistant elevation. On a maglev line would be ideal and the skateboard lets it go at the end of the track.

@sethdayal

Radioactive waste produced by a coal fired power plant? Um dude, you're confused, last time anybody on this website checked, coal fired power plants don't burn Uranium, or Plutonium, or anything that is more radioactive than the graphite in your pencil... a NUCLEAR explosion at the bottom of the ocean would produce more radioactive waste than if all the coal on earth were burned at once...

And do you know why the Chinese won't put that plan you mentioned into action? Because they aren't idiots. All that radioactive fallout (from even one launch like that) would kill most aquatic life in the region, crippling most asian sea born economies. The fall of such economies and the lack of a large source of food would cause social upheaval, crippling probably entire societies, and I wager cause the start of WW3...

That said i'm pretty sure it's not "in the works" as you stated.

@dirk

"No, the *point* is the scramjet itself. Launch something out of a rail gun and it will steadily decelerate due to gravity and resistance. It doesn't get you anywhere; it's a Wile. E. Coyote approach to space."

Actually if you get it going fast enough it would work its just we cant get anything going that fast yet..

99.9999999999999% of an atom is empty space

Why don't spend they're time and money in researching how to launch spacecraft by using electricity? If they can manage to do it with electricity it'll be far cheaper!

- http://www.geek.com/articles/chips/plant-virus-makes-lithium-ion-batteries-last-10x-longer-20101210/

@scubasteve

Interesting post! However, there is uranium in coal. Burning releases it. See gov't report here: http://pubs.usgs.gov/fs/1997/fs163-97/FS-163-97.html

It's not necessary to have the rail gun pointed "up". A horizontal launch would be tangental to the Earth (it's round, remember)-- the further "out" you travel, the further "up" you are.

Also, consider that the idea is to launch an airplane. Once launched, the airplane (whether working off turbojets, or scramjets) would be able to change its angle of ascent. IOW, it could easily convert forward momentum into vertical climb.

Finally, the plan calls for a scramjet. Scramjets need to be travelling very fast, before they can be fired. A very fast horizontal launch, from a rail gun, followed by a boost from a turbo jet, would be the best way to get the scramjets up to speed. A vertical launch would require a lot more powerful railgun, to reach the required speeds.

I have a proposal that can do better than this, all the energy is used by ordinary trucks and pumping stations in getting mass on top of a hill. The mass generates acceleration the old fashion way, down a hill. It's called gravity assist, the old classic Galileo way of accelerating an object.

1/4 of the rocket fuel used on the space shuttle is expended getting up to 400 kilometers per hour the speed of a rocket launched sled using gravity assist alone to get up to speed, therefore a two stage to orbit space plane can be launched, this isn't rocket science folks this will really work it is about 400 years old technology, an object accelerates down an incline.

Ron Bennett

@VoodooX and @SKRIBE'

i don't think your proposal would be realistic for manned flight.
one of your assumption is to rely solely on momentum for the atmospheric part of the fly, which requires to accelerated the air/spacecraft to insane speed at ground level.
this will probably kill any pilot or passenger and/or melt the fuselage of the ship. assuming enough momentum will be left to reach 200.000'.

I'm surprised the author / PR writer used the term "rail gun". Later in the article the track is called a "linear motor", which usually refers to a very different sort of track.

Conventional magnetic levitation combined with a linear motor would probably be the best near-term tech for this sort of launcher. A rail gun is for launching small projectiles at very high velocities.

I guess they used the incorrect term "rail gun" to create a false link with recent news on rail gun weapons development...

scubasdsteve87,

A typical old tech 1,000 MW coal fired power plant releases more than 5 tons of uranium and 12 tons of thorium each year.

Even modern plants with ash capture still generate the waste, it is just stockpiled in the captured ash. This radioactive waste is due to the naturally occuring trace amounts of uranium and thorium in coal.

Here's a link that discusses it from a farily technical viewpoint:
www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html

Right, that's the whole idea here - the railgun just gets the engine up to operating speed. Voodoo, I understand that it would be *possible* to shoot things into space on a rail gun, but that's not what's being proposed here, it would take a hell of a lot more energy, and it would take a hell of a lot more than a two-mile track.

@Dirk Mcbratney:

"So here's ... my question. How exactly do you put *people*, which the article *specifically mentions*, on a device that accelerates to Mach 1 in *two miles*?" (Dirk)

I could tell you to read the article, where it says:

"The craft accelerates from 0 to 1,100 mph (Mach 1.5) in under 60 seconds— fast, but at less than 3 Gs, safe for manned flight."

However, the article is obviously wrong -- or at least grossly misleading. A decent sport car could cover two miles in under 60 seconds, from a standing start; so, it is obvious that the launch is going to take a lot less time. If the craft is accelerating at a uniform rate; and reaches Mach 1.5 in two miles; it's going to get to the end of the rail in about 12 seconds. Sure, the article says "under 60 seconds" -- but, 12 seconds is a lot under 60 seconds.

That said, the rest of the article is correct -- 3Gs would do the trick, and it would be safe for humans.

concepts :) aren't they fun?

Using a railgun is a good alternative to launching a vehicle, as it wouldn't be as expensive to do, and it shouldn't require as much fuel. Using it throughout the entire launch is not so smart though. Simply put, why would you require more energy of the railgun when you could use the air already rushing past you to your advantage instead?
Scramjets work quite well in that regard ;)

Cool, but use a plasma rocket for the spacestage. Sounds great to me!

I-pads
Mobilephones(Cellphones)
Now Fireball XL5 What ever next?

What about lifting a rocket to the edge of space with a balloon,and then lighting the rocket to attain orbit? It would cost a lot less than building a multi-billion dollar rail-gun launch system.

Good idea -- here's an improvement. Build the track up the side of a large mountain at the equator. If the mountain is 10,000 - 14,000 feet high, that drops the air resistance at launch time. The combined craft is already two miles high. Launching toward the East you get another 1000mph in the rotation speed of the Earth.

Landings are done near sea level so slower landing speeds are possible.

So that's my idea. I have a lot of good ideas -- all of them ignored.....

This idea is great, but has any body here thought about how to keep the plane on the track, or even centered? Because at 1100 miles an hour i would not want to catch that track.

You kids are all clearly stuck in the paleolithic age, teleportation is clearly where it's at.

I just say do away with the humans and have the thing shoot at full speed into space... the only thing human onboard are frozen cells and robots with an automated lab for growing and developing your future colony. Only problem is accelerating the development of the crew and training them to operate the ship - minor problem :)

There's also a problem with delivering that much electricity into the rail system. If the thing is burning 180Mw then you need to store a whole lot of energy in a system that can deliver it fairly rapidly without sustaining much damage. It's not something that can be plugged into the grid and fired at will. If you give it it's own power plant that detracts from it's efficiency since most large generators will need to be on for a lot longer than the 12 to 60s launch time.

In any case, whatever the cost is, we can expect it to be 10 times more expensive with the government holding the reins.

demonduck...i been saying this for some time too...powered by a nuclear reactor...its an idea that cant hide forever

lnwolf41
No one here has mentioned the use of banks of capacitors along the track/rail line. they could be charged slowly reducing the strain on the power grid. Use a cooled superconductor to relay the trip signal with little to no resistance, also by using a cradel you reduce The overall weight of the craft. Build the system in the salt flats or desert with several mesa's. One other thing with an unmaned payload you could ramp up the intial velocity and use less fuel during flight or go from rail to rocket into orbit saving the scram jet for passengers flight.

Accelerating to Mach 1 over two miles is easily humanly survivable and I would guess the G loading would be well less than half of an aircraft carrier launch .

Shooting a space borne payload "straight up as some have suggested is foolhardy since that would make it impossible to enter orbit (which is just falling in an arc that perfectly matches the earth's size aka "falling with style")

Dale

"The craft accelerates from 0 to 1,100 mph (Mach 1.5) in under 60 seconds— fast, but at less than 3 Gs"
Hmm. At 3 Gs:
v=at
t = v/a
= 1100 mi/hr * 1 hr / 3600 s * 1609 m/mi /29.43m * s^2
= 16.71 seconds. Yes, that is less than a minute. A bit of an understatement there.
d = 1/2 a*t^2
= .5 * 29.43m/s^2 * (16.71 s)^2
= 4108.26 m * mi/1609m = 2.55 miles
but not a 2 mile track

@twooding
Or you could always do it the other way too.
2 miles = 1/2a*t^2
3618m=.5a*3600s
(3618m/3600s^2)*2=a
=2.01m/s^2 Much less than 3Gs

but then that also defeats the whole point of the system going that slow... so ignore that last comment.

That would be a capacitor bank in the vicinity of 3GJ and it needs to be delivered in under 17s, based on other people's math. Of course, it will probably need to be higher than my estimate after leakage, resistance, and other factors. Whatever materials they use to deliver that energy, the system is going to require some innovation.

all this bs inferior technology is boring me, come back when the photon torpedos has been added.

Maybe if we lengthen the track to build up more speed so we can dump the turbojets and go straight to scramjets. Less weight, more payload.

Jules Verne...Jules Verne...how did you see the future?

its like a space Prius!

@ Dirk McBratney: ("So here's ... my question. How exactly do you put *people*, which the article *specifically mentions*, on a device that accelerates to Mach 1 in *two miles*?")

At 12 g's of acceleration, the max sustained accel. a human can take applied perpendicular to the spine, the craft would reach mach one in 1800 feet, less than a fifth of the proposed two miles of launch track. The required acceleration would be well within human tolerances.

This will never work.

NASA should solve the anti-gravity problem then the universe is at our door step.

Several solutions to anti-gravity have been proposed including the one at

www.colossalstorage.net

With anti-gravity solution could lift cities to outer space.

@ cs4:
If you get rid of the turbojets, you can't do a low-speed powered landing. Also, BEST case is that track length, cost, and energy use rise with the square of final velocity, so going up from Mach 1.5 at the end of the launcher to the Mach 4 that the article specifies is necessary to light off the scramjet would take, AT BEST, (4/1.5)^2 = 64/9 or about 7 times as much track, motor, and energy storage. That being said, I hate the turbojets too - let's reduce payload, increase acceleration by dropping the requirement that it carry passengers, and build a space gun/plane.

I believe this is a variant on the old (ca. 1995) Black Horse spaceplane concept that was supposed to take off lightly fueled and fuel up with tankers (KC-135s or something). The catapult allows the plane to take off with a full fuel load, allowing us to dispense with the tankers.

Hmmmm... let me know when headlines read "NASA Engineers Propose Putting Rail Gun on a Spacecraft". *pew-pew-pew*

I hate you iRobot.

Pop Sci did an article on achieving space by "rail gun" Problems arise with the amount of energy needed and how it either needs to be really tall for thin atmosphere (cost limited) or when it exits the end on of the tube the sonic boom will flatten a few miles of whatever is nearby.

This is really no different than every other idea that has been floated for public consumption; it always takes at least 10 years to get to the next step.

We have been going to Mars since the age of the Apollo program and each time it is promised, the reality of such a flight is just over the far horizon. And each time we get close enough to see it, the time scale is pushed back yet again just out of sight.

It is almost a foregone conclusion that the generation that grew up with Apollo, will never live to see a human on Mars or the advent of a new means to even get into low Earth orbit. The chances are not much better for those younger generations that have followed.

The problem is not technology. It is having the will and political courage... items that have been so notably absent for decades now.

Pop Sci may take a well deserved bow here for a very good story... but they are in no better a position than anyone else when it comes to having the immortality needed to see any of this ever come to reality.

@rlb2: Gravity assist actually refers to a vehicle already in orbit which gains speed by passing near a planet.
http://science.howstuffworks.com/dictionary/astronomy-terms/question102.htm
http://www2.jpl.nasa.gov/basics/grav/primer.php

What you're suggesting appears to be going downhill to pick up speed, then using the momentum to go uphill. The only problem is that you can't go much further uphill than downhill, if at all.

Final velocity squared minus initial velocity squared = 2 times acceleration times distance.
With the initial velocity being zero (starting from rest at the top of a hill) and the acceleration being -9.8 m/s/s (acceleration due to gravity on Earth), speed increases as distance decreases (d<0 because you're headed down).

However, when you bottom out and start heading upward, things change:
The final velocity is now the initial velocity, and it still equals 2ad, so the final velocity is zero, and the distance doesn't change.

This doesn't even take into account the friction or air resistance involved.

If you started on a mountain, you'd just end up back at the mountain's elevation. If you started at ground level, you'd have to go down and then just end up back at ground level.

If there's a part of the process I've misunderstood, let me know. If it does work it seems like this would be a nice, simple solution.

What if we keep using the quite successful solid-fuel booster rockets we currently employ, but now attached to the launch vehicle, the 'rail-gun' sled, thereby removing the need to launch their weight as well?

And now that we have a rocket engine propelling the launch vehicle across a mag-lev track, we design the track to function in part like a generator, using energy from the fast-moving rocket-powered sled to induce current into the mag-lev system; and also, if I'm not violating conservation here, supplementing the current required for magnetic propulsion of the sled as an adjunct to the rocket thrust.

In my defense, I am neither a PhD nor a rocket scientist.

Adjunct idea: Make the sled a two-stage vehicle, with the rocket-propelled stage providing thrust to both separable stages while simultaneously powering the linear motor to produce current for the mag-lev and mag-propulsion of the second stage. It seems that if the rockets are powerful enough and have a long-enough burn time, that the mag-propulsion of the second stage could allow it to accelerate away from the first stage even while the first stage is still thrusting to power the linear motor. Of course the second stage would have the assist from the orbiter rocket(s), which by then would have to be at full thrust.

The equator at the coast of Somalia would be perfect.
Launch east over the Indian Ocean.
Drill a 20 degree tunnel back toward the west, 5 miles.
Around the site, install solar panel which will be used to charge battery banks and power up dynamos.
Use a series of dynamos to generate the electricity required along the track. Massive concrete dynamos can store enormous amounts of on demand energy.
The return landing strip would be place right along side of the launch tube.

This new SpaceLev industry converts Somalia into an economic boom country. Puts the US and other space nations in the region with instant launch facilities for "other" types of launch vehicles.

Expansion of the number of tubes and solar acres would be made north and south.

It's already dreamed up: wikipedia - spacetram

en.wikipedia.org / wiki / StarTram

They should just make the rail gun about 100 miles long. We have roads much longer then that by far and gives you plenty of room in case you need to abort. In 100 miles you should be able to reach escape velocity and you can dump the scramjet.