Physicist Proposes Using Cannon to Fire Payloads into Space

If memory serves me right, the Lawrence Livermore Lab's hydrogen gun was developed so meteor impacts and other projectile impact effects could be studied. So the payload was never intended to survive the experiment. A little simple Newtonian manipulation of the 6 kilometer per second muzzle velocity, a 1.1 kilometer barrel gives me an average acceleration inside the barrel of 1668 g's.

a=V_f²/(2*L) With V_f=6000m/s and L=1100m, this gives me about 16,400m/s² acceleration. The article said that a rocket engine in the payload will then be controlled to permit orbital control. Can anyone build a rocket that can survive 1700 g's? Maybe they want to promote shock protection packaging design.

I am certainly all for research, but it should at least be plausible research.

Possible potential plausible survivability depending on the electronic payload.

The WASP UAV was designed to handle up to 15,000g and was launched from 155mm field artillery.

http://www.edn.com/article/CA341454.html?text=WASP

http://www.metisdesign.com/wasp_example.htm

The UAV mechanics survived testing but I am note sure if they successfully incorporated electronics and cameras (there has been little information since 2003 so perhaps the project failed or it succeeded and was made classified and taken out of the public domain).

Well I guess for some payloads this will be a plausible launch platform. Certainly not a method for launching a human being, but for some satellites a possibility. Nice find Jack.

Here's another example - electronic precision guided artillery rounds fired from mobile artillery.

http://en.wikipedia.org/wiki/M982_Excalibur

Saw a documentary on it on Discovery's "Future Weapons" a while ago, quite impressive.

Standard artillery shells have a muzzle velocity of anywhere between 400 m/s and 1600 m/s so while significantly slower than the 3 km/s quoted I think we can assume these are subject to significant g-forces, yes?

With this in mind address the Excalibur M982 "smart" artillery shell which has a GPS based guidance system to allow extreme accuracy.

Note; the "X" designation has been dropped - this is an operational weapon.

John Hunters launch device seems a little more plausible when taken in this context, agreed?

Just a clarification in the numbers.

The 3km/s speed cited in the entry posting is what the Lawrence Livermore gun produced. The satellite launcher in the linked article is supposed to get 6km/s.

Would it be possible, when firing humans, to build into the passenger
unit a suspension which would absorb the initial thrust on them?
Like a field gun with a recoil spring. A sprung sliding compartment;
perhaps compressing a gas in a chamber? To absorb the initial "kick."

I always thought the idea of economically "firing" units into space
could be quite viable, either electronically, or other means. e.g.
a solenoid driven type projectile, or this explosive gas charge.

jt.

In this case it cannot help. For the passengers must leave the barrel with the projectile or they're not going anywhere. (Actually the mush that use to be passengers.) I calculated the average acceleration required to leave the "launcher" barrel from the data given in the article. The shock absorber system you describe would soften the impulse acceleration that would likely occur in going from zero but cannot effect the average.

Attach the passanger behind the projectile with a bungee cord.

"Would it be plausible..."

redfred's post #1 gave me pause, reflecting on a concept that I've dwelled upon, off-and-on for years now.

With "free-energy-from-the-oceans" being an oft-discussed topic... why hasn't NASA (since its first mention of a possible offshore launch platform) considered such a Firing-Tube device ... but...

...anchored to the seabed (like a tension-legged-platform); surrounded by platforms having enormous pumping facilities; using lots of 'free' water-pressure-energy to get things moving (pressure is already approx 0.45psi/ft on bottom). At some point {feel free to help, redfred} CO₂ assist could be added, as in submarine-missile launch...

Loads of room for engineering-fun with this one (Del). Maybe even mechanical cat-fish to keep other marine life chased out of any possible harm's way...

Who's our resident oceanographer...? Where would be the safest/deepest/least-affected-by-currents spot in the bathyal depths??

Feel free to call us for installation quotes...

Sounds good! A vertical tube into the sea, (water pumped out)
with the space unit in the tube sealed at the sides.
It sits on top of an air cushion with the sea water then released
underneath it. The cushion "floats" to the surface under the
immense pressure of the sea water.
- what is the exit speed of the unit at the surface?

jt.

Does it float my boat!

As stated above "{feel free to help, redfred}", I'll defer to others, with respect to the math here ... [I have more than my fair share of numbers/equations with which to deal!].

Just seems as though gaining the INITIAL momentum for any space-bound craft that we have launched thus far consumes way, Way, WAY too much explosive energy.

My father spoke of being the "Safety Officer" at White Sands, testing a number of V2's in his early years. Standing atop a gantry to make the "final connection" scared the eebie-jeebies out of him, knowing the potential of the fuel / oxidizer below him.

We have suffered a number of tragedies in our race thus far ... some due in no small part to the enormous quantity of fuel required just to "get-things-going".

I have always thought that finding a non-explosive 'sling-shot' method of getting things going would be a dramatic impetus to the program, leap-frogging us out of the seeming doldrum that we've been in for decades now.

Just my two cents sense worth...

"PS"~ "exit speed" depends on more factors than *I* could calculate, including how big those "assist-pumps" could be (see post above), and, whether CO₂ was employed as a boost at some point, and what sort of 1^st stage rocket motor design would/could be optimized for such a project.

sounds like a great dream! but whose gonna make pipe that big!

float my boat! ------ one of my fav sayngs as a kid was "whatever floats your boat!"

it beats the simple "WHAT-EVER!" that most kids say nowadays in fact someone said that on tv recently that that is the most annoying thing people say these days!

" Oh , WHATEVER! "...

Since the guests deserve civility now and again... here goes: (remember, this is simply an idea based on knowing "this-that-and-another-thing-or-two", and wondering what is really stopping them from being put together....(?)) To repeat from my original post (above):

It isn't simply a 'door/port' that gets opened at the base, letting water slowly gurgle into the tube...

...there would HAVE to be enormous pumps involved. (Still, safer than tons of explosive fuels, me thinks).

The legs from the "Pumping Platforms" could be used (to save on materials) to pipe water down to the bottom (below point "A")...

As the projectile/ship/(whatever) reaches points "B" and "C", additional (pressurized) water and/or gasses (?) get introduced via huge flexible lines such as those that fill tankers... in addition to whats still going in the bottom.

Somewhere around point "D", the initial booster stage would kick-in, requiring some of that "shock-absorber" concept mentioned by jt (post 10)... but more like special multi-layered seats than a slung 'compartment'. Thus, the wad is discarded due to the scorching it takes. Yes, I'm sure the internal pressure in the "pipe" would be "dangerous" at the top (on exit) ... (reinforcements not shown here) ... and I'm sure that the pressure would dictate special requirements for the booster, if not the remaining stages and capsule/payload as well. Here, "Timing IS everything"...

No more "answers" til monday. Have a blessed weekend.

Oh..."PS": it ain't 10 miles deep/long, either... (again, refer to my initial post: "bathyal depths")

Sigh. This improper mixture of forces is exactly where people get P machine ideas.

The payload sits on it's seal at point A. I will ignore the friction that occurs through orifices that will reduce pressures and the rubbing of the seal on the tube. As the water fills the cavity under the payload the payload will move up for the tube. The net force on the payload is the water pressure at the bottom times the cross section area minus the weight of the payload. As the payload moves to B then the pressure will be the pressure at B times the area minus the payload. But the pressure at B is not the pressure at A for the weight of the water from A to B will reduce this pressure. So at some point before reaching point D, no net force will be pushing the payload. To reach point D the payload, and the water must have enough inertia to reach D.

Don't believe me, take a glass of water and a drinking straw. Put your finger on the top opening of the straw before you put the straw into the glass of water. The straw will be filled with air and no payload. When you release your finger the water rushes first quickly into the bottom of the straw. Depending on how high the top of the straw is above the water line you will only get a slight, brief surge of water in the straw above the water line. Remember this is better than what you get with any load to push against.

whats bathyal depht mean ----- the depht of you bath water?

Nah, just think a little more. The high water pressure outside of this launch tube will not be of any help and can only hurt. For if you intend on flooding the bottom of the tube with this water, then this pressure will go into moving the payload and the mass of the water filling the tube. There's a very good reason the guys at LLL used pressurized hydrogen gas. Now how the water can hurt this launcher. At the bottom of this launch tube the pressure will be compressing the diameter of the tube much more than at the top of the launch tube. This will make maintaining a reasonable seal between payload and tube more difficult. Lastly, a submerged submarine ICBM missile launch is done near the surface. The pressurized gas bubble and spring under the ICBM provides the force for the missile to move the water above the missile out of the way enough so that the missile will be above the surface before ignition.

Re : "At the bottom of this launch tube the pressure will be compressing the diameter of the tube much more than at the top of the launch tube. This will make maintaining a reasonable seal between payload and tube more difficult."

Ahhh...! But this is what engineers do, n'est ce pas...?! Flexible seals are absolutely positively not new. (Again, Dad's expertise / not mine, here) When difficulties were encountered designing a steerable 3rd stage nozzle for a certain era (warhead) ... when he entered the project, his take on it was: "Why not make it flexible (layered fiberglass and rubber) and allow it to be consumed during use? It doesn't have to LAST, so as to be reused!" [The FlexSeal nozzle...It worked GREAT.]

Our country has had craftsmen throughout its history who are great at working with wood products. (Think I'm nuts, yet?) Today's high-tech CNC-type woodwoorking shops would have composites, rubbers, plastics (as well as flexible metals, etc. etc.) with which to bring-together disposable one-shot 'wads' that could accomodate such launches, I am certain.

Between submarine hulls and offshore oil and gas wells & associated facilities, a lot of "caisson / pontoon" work (and thus, data-bank) has already been accumulated.

I, for one, would be happy to sign-up for such a ride...

But what would be the advantage? No matter how easily a drawback can be overcome, any drawback from doing something without an advantage in return seems foolish to me.

hmmm...

Static launch at ground level:

2000 lbs fuel just to lift everything the 1st foot... 1975 lbs fuel to get it all the 2nd foot... 1950 lbs to get it the 3rd foot... 1925 lbs to get it the 4th foot... (or, "whatever-it-is")...

The gargantuan-titanic-enormity of the explosive force required just to start-to-begin-to-commence-to-initiate a veritable "crawl" skyward...

Keep doing this enough times, especially with "reusable" boosters...

There really aren't all-that-many people who would willingly sit atop a firecracker big-enuf to "pop" them into space.

IF a significant amount of the earth-trembling "boom" of lift-off was able to be traded for a "ka-whooosh!" ... me thinks a whole lot more payload & people could be sent up with greater safety, and, at much greater frequency. Meaning, ultimately ... get much further-on much more quicklier......that's all.

Ok, but I don't see anywhere in your reply anything about using water pressure from the sea floor. You've given me a non-answer.

You know if we could just use all the pressure from the core of the sun to lift the economy, there be no complaint about Icelandic freedom.

"ok"...My apologies for not spelling-out all the details (just pitching-out the gist, so-to-speak)... but...

please refer to (my) original post #12 above:

"surrounded by platforms having enormous pumping facilities; using lots of 'free' water-pressure-energy..." ...was meaning to paint the picture of mechanical energy effectively magnifying the pressure (as noted, already on-bottom)... I have seen some pretty impressive pumps in my day; and, I am sure that *they* are not pushing the envelope of capacity by any stretch of the imagination.

And, once again ... the water itself is NOT intended to act like that in a child's pump-up toy plastic water-rocket _ only-a-gazillion-times-better-fully-putting-a-payload-into-space. Repeat: NOT.

Using its potential is merely envisioned to eliminate the veritable clap-of-the-Almighty explosive thunder required (by our current processes) just to get things rolling, and headed the right direction; with, hopefully, less chance for a deadly flip-over-nose-dive to death for anyone (or anything). [Tell me *that* has never happened, and will never happen again...]

Blessings to all ~

you said "2000 lbs fuel just to lift everything the 1st foot... 1975 lbs fuel to get it all the 2nd foot... 1950 lbs to get it the 3rd foot... 1925 lbs to get it the 4th foot... (or, "whatever-it-is")..."

The public television show about Hubble's repair states that the shuttle burns 11,000 lbs of fuel per second during takeoff.

I wonder how far it actually moves during the first ten seconds after ignition (google cant seem to find the answer.

I am tempted to make a drawing, but hopefully can describe it well.

Imagine a vertical tube as wide as the missile/rocket, to the sea bed.
Around the base of this is a "slide" cover, which when dropped exposes
the base of the tube flooding the whole bottom (of the tube) instantly.

Surrounding the firing tube (doughnut style) is a much wider tube which
rises higher than sea level, say 100 ft into the air. (or several wider tubes.)

This is filled with sea water to the top to add to the firing tube water
at any point necessary in the firing tube. There is now a massive amount
of water giving pressure well beyond the exit point of the firing tube.

i.e we have a firing tube, within a much wider tube(s) which are higher than
sea level. Dropping the all round base cover plate exposes the firing tube
to a massive amount of sea water under pressure from a considered height.

Filling the tube would be no problem, as only the last 100ft (ish) is pumped,
containing the pressure the same, by the structure of the twin(+) tube walls;
sliding (dropping) the release plate (sleeve) down no problem; and the auxiliary
tube(s) would only need a height to give the firing tube a required exit velocity.

What do think guys? Would it work? You don't need a diagram to visualise this?

jt.

ok, so it didn't float my boat... you sank it; how childish is that!

ps - logged-in now - jt.

Now were talking , redfred just wants to prove it cannot be done! Instead of nope that won't work the reply should be Here is what would need to be done to make that work.

I think the picture intends to show multiple pumps like in water pumps (10,000hp each time 4 maybe)? But instead, whats needed is large tubes like the one for launching (all full of water) standing higher than the sealevel . and then whats missing is pneumatic over hydraulic power; for several days before a launch , air would be compressed sufficiently in some additional tubes. Then the compressed air is used to blast the water from the standing water-filled tubes into the base of the launcher tube, thus rushing the missile out of the launching tube.

Thats kind of more like how the toy rockets work ecept for a much larger scale.

Tell us how big the rocket will be size and weigt and wel'l have fun with the math (tube sizes ect air pressures ect). Now thats fun!

I like the idea. There is a lot of difference between 47 metres and 1.1 Km. Explosives can be designed to start off slow and build up pressure as the projectile moves up the tube. You've got 1.1 km (or more) to play with. I like the ocean based idea. This is only for payloads, not people, but if you insist, we could send Vermin up as an experiment. You could also have the projectile be a rocket that would ignite after it exits the cannon. I think this is doable.

So who's going to feed the giraffes after I'm gone???

Any royalties please? (follow the money.)

jt.

It's no shame to be poor... but it's no shame to be rich either!

Jules Verne would be proud...the world finally listened to him...again.

Having re-read r-f's post_27 a second time before shutting-down friday night, and thinking on it over the weekend, it became clear to me...

...even with a dozen of the enormous pumps being considered, by the time the column was approaching the top of the tube (as redfred emphasized ... adding-to the head against which the pumps are working), the velocity of such a projectile / missile would not be sufficient to consider this approach.

However, it appears that a Guest (or two?) may have offered a viable alternative force mechanism...(?)

Gotta dig-out some data (Gas Laws, etc) and toy with how much (compressed air) piping would be required to effectively push said water column up the launch tube.

Now, how heavy IS that "Shuttle-Replacement"...?!

Story on FOXNews.com about a concept for a 1 kilometer long space cannon powered by hydrogen and submerged below the surface of the ocean. There is a company named Quick Launch Inc. that was created to try to sell this idea.