AHC: Reach Space by 1900

I don't know if this has been done before, but it might be an interesting thought experiment. Which PoD(s) could allow humans to exit the earth's orbit orbit by the year 1900? What's the latest PoD which would allow this?
 
Don't think is really needs a POD, as such. Large gun tec was nearly there in the late 1890's. More money spend on these large cannon (for want of a better word) maybe able to get something into space, not orbit. Some navel guns could shoot stuff 8 miles, or more by then.
Getting a stable and guided object is something very hard. Rockets were still something 'new' in the 1930's and the Germas still had trouble in the 1940's.
A new 'mega brain' would be needed. A new Newton? Plus much more advanced electronics and the need to work with light weight metals.
Plus liquid would be great.
If there was a POD it should happen by 1885.
 
Don't think is really needs a POD, as such. Large gun tec was nearly there in the late 1890's. More money spend on these large cannon (for want of a better word) maybe able to get something into space, not orbit. Some navel guns could shoot stuff 8 miles, or more by then.
Getting a stable and guided object is something very hard. Rockets were still something 'new' in the 1930's and the Germas still had trouble in the 1940's.
A new 'mega brain' would be needed. A new Newton? Plus much more advanced electronics and the need to work with light weight metals.
Plus liquid would be great.
If there was a POD it should happen by 1885.

WHOA NELLY!

By "Reach Space," do you mean simply "fire a cannonball into a 360 degree semiballistic orbit so it can come round the Earth and blast the very gun it was fired out of?"

Because firing guns alone, that's all you're gonna get.

Actually in principle, every shell fired out of every gun, including a BB gun, is in orbit. In a semiballistic orbit (one seriously modified by air drag, of which more anon). And so are you and I at the moment; whether we are standing still or flying in an airplane, at each instant we are in a ballistic orbit, one constantly being changed by the accelerations we experience.

A shell fired out of a gun with exactly half the kinetic energy it would have at escape velocity would have just the energy it needs for a circular orbit. If we fired it sideways, and could ignore air drag and the fact that objects would get in its way, it would be in a circular orbit. But we can't ignore those factors, we have to lob it upward as well as sideways. Diverting some of the kinetic energy into upward motion means it has less angular momentum than it would need for a circular orbit. It is in an elliptical orbit, one that intersects the point of launch. We can throw more energy into it, but all we get out of that is a more elliptical orbit with a higher apogee; it still whacks back into the surface because the ellipse must include the point of launch. We could in principle fire with more energy than escape velocity; then it will never come back--ie the a apogee of that ellipse is at infinity--it's really now a parabola and firing harder yet just gets us hyperbolae.

To achieve a circular orbit, we'd need some kind of second acceleration, first to lob it up to the height we want, second to speed it up there.

But how are you going to incorporate any kind of secondary firing mechanism than can survive an initial launch out of a gun?

Meanwhile we just can't ignore the atmosphere. Air drag is already a force that seriously alters the ideal trajectories of the relatively slow projectiles we fire here on Earth. But orbital velocities are something like 8-10 times what guns on Earth are known to achieve; air drag on a given shell would be hundreds of times worse.

And of course to achieve muzzle velocities close to 8 kilometers/sec, we need guns that can handle bursts of energy something like 100 times more than in OTL guns firing the same sort of shell. More than that because we need the shell to have enough velocity to overcome drag and still have full orbital velocity left over.

Not to mention the astronaut fired out of such a gun will instantly become a fine red mist.

So--we need guns 100 times more powerful than anything OTL, to achieve a single suborbital trajectory that, an hour and a half after firing, brings it round and down to blow its own launch gun up. Forget putting a person in there or any kind delicate machinery in there!

Now, if you are prepared to leave the Jules Verne Space Gun club, and look instead at rockets, we'd need to burn either the same fuels used OTL five decades and more later, meaning engines that can take the same stresses and operate as reliably as the ones we had OTL. Metallurgy has to be much more advanced than it was in 1900 in our time. Or we use inferior fuels that are easier to burn, but they won't produce the same specific impulse, hence the fuel tanks must be much bigger.

To make this possible by 1899 would require that many many fields of endeavor be very much improved. A POD 15 years before will not do it.
 
We could start with someone other than the British getting ahold of Tipoo Sultan's rockets in the Anglo-Mysore war of 1799.
 
That is what I mean by using a gun, just getting something into space.

Well, it depends on what you mean by "in space." If you just mean "get some inert object above some arbitrary altitude," the easy way is to fire gun or rocket straight up. Say we call "space" 200 kilometers up, and all we ask is that a shell coast up to there, stop, and fall back down. Well, that would only require a muzzle velocity of 2 kilometers/sec, just a quarter of orbital. (Actually muzzle velocity needs to be higher to overcome air drag). However, bear in mind that during WWI, German "height-climber" Zeppelins hoped to bomb Britain with impunity by flying five kilometers or so high; later a big part of US strategic bombing doctrine was to fly very high, again so as to get beyond the effective range of ground based German or later, Soviet, guns. Effective range might not mean "higher than the shells absolutely reach," it might have been mainly a matter of spoiling their aim by forcing a very long time lag between firing the gun and the arrival of the shell. Still I believe even the best German artillery of the second war era would have been very hard pressed to push a shell even 50 kilometers up, let alone 200. So you are talking about making a much better gun in terms of muzzle velocity than the best things Hitler could order, a couple generations after the OP deadline. Also check out the "V-3," Hitler's third-string Vengeance weapon--it was to be a cannon that could strafe Britain. Note, not a cannon that could strafe New York or Moscow, note also what a big and complicated monster it was, with second and third stage booster shots to further accelerate the shell stationed like chevrons along the barrel. Could this contraption have fired a shell straight up to reach 200 km height? Maybe. But it was being designed in the 1940s, not before 1900!

We could start with someone other than the British getting ahold of Tipoo Sultan's rockets in the Anglo-Mysore war of 1799.

Or why not have the British just make the better use of them you think a non-Brit would have?

No matter, a gunpowder rocket will not cut it for reaching orbit. It isn't clear to me how much gunpowder combustion is a matter of reacting with oxygen in air and how much it explodes based on reacting materials it already contains. The more oomph it gets from air, the more clearly its function would be degraded on the edge of space.

Vice versa, rocket performance is degraded when the gases need to rush out against air pressure, and by the late 19th century improved forms of gun explosive that clearly did not need air to work at all were in development. A rocket fuel is different from gun explosive anyway; the latter you want to go to complete reaction as quickly as possible so its complete force is available to propel the projectile in the barrel; you want rocket fuels to be burning over an extended time. Solid fuels can indeed be used to get to orbit; modern ones have performance about 2/3 as good as fair liquid fuels.

The shuttle main engines have ISP in the range of 420 or so as did the hydrogen/oxygen burning upper stages of the Saturn V; using kerosene and oxygen instead the booster stage had one around 300, which is also typical of "storable" liquid propellants such as those used in the Titan missile, which also launched Gemini. Mercury was launched into orbit on oxy-kerosene Atlas rockets. IIRC the modern solid fuel boosters used on the Shuttle had ISP in the ballpark of 200; I might therefore believe that a dedicated 19th century program of solid fuel rocket development might achieve something like 150. The basic rocket equation is exponential; divide total change of velocity required (including virtual velocity as in overcoming gravity and air drag) by the effective exhaust velocity, and take the exponent of that and you have the ratio of total rocket mass before firing to what finally reaches the target speed. ISP such as I have cited is the amount of kilograms of mass a kilogram of propellant per second can thrust at one G; a G is 9.81 meters/sec^2, so roughly speaking multiply them by 10 (less roughly, by 9.81) to get the effective exhaust velocity of various fuel mixes--bear in mind they are lower in the lower atmosphere, and that a nozzle designed for good performance in vacuum is different from one that gives the best performance in air.

"Mission delta-v" is a conceptual way of summing up all the velocity change needed, including the virtual parts, to achieve a given goal; to achieve its 200 km nominal circular orbit the Shuttle had a mission delta-V of about 9 kilometers/sec. With rockets putting out exhaust at about 1500 meters/sec clearly the ratio is exp^4, or about 55. So less than 2 percent of the pad mass is going to get to orbit with these kinds of solid, and that 2 percent includes the mass of the rocket itself as well as payload. Using the idea of staging we can improve things a bit; it solves many problems. (The lowest stage engine is the one that has to worry about thrusting in atmosphere for instance; we can design them for thrust there and the upper ones for thrust in vacuum). OTOH when I try to estimate necessary launch pad masses for systems of a given performance using just the rocket equation I always wind up underestimating it, even though I'm not attempting to factor in the economies involved in staging.

What are we trying to get into orbit? If all we want to do is orbit something that people on the ground can see is orbiting in their telescopes, the rocket will still be big but not nearly as enormous as one that puts up a capsule that contains an astronaut. Since we are talking 1900, clearly the only way to get anything useful done in space is to send up a person.

But now we have to worry about getting that person safely down to Earth again. 19th century science would be only moderately useful in designing a survivable reentry method. Tsiolovsky was I believe then already on the right track in suggesting some kind of ablative dumping of the orbital energy--he suggested carrying water and keeping the outer hull acceptably cool by evaporating it. That would require a lot of water, which greatly adds to the minimum mass that has to be launched along with even a very small person.

So yes, I suppose with rockets, solid fuel rockets, and a POD much earlier than 1885 (this stuff is going to take a lot of time and effort to develop) some sort of steampunk Vostok might be launched by 1900, and its astronaut even returned safely to Earth. The effort and time involved in just getting some silvery sphere into orbit just so you could point at at and say "I did that!" is somewhat less, still more than a 15 years project I think.
 
In King David's Spaceship by Jerry Pournelle a primitive world puts someone into orbit using a craft with a rapidfire cannon fitted to it. They ask some offworlders to recover the capsule because they have not developed technology for it to re-enter the atmosphere.
 
Well, it depends on what you mean by "in space." If you just mean "get some inert object above some arbitrary altitude," the easy way is to fire gun or rocket straight up.
Right. The first man-made object to enter the stratosphere was a shell fired by the Paris Gun.
 
In King David's Spaceship by Jerry Pournelle a primitive world puts someone into orbit using a craft with a rapidfire cannon fitted to it. They ask some offworlders to recover the capsule because they have not developed technology for it to re-enter the atmosphere.

yeah. the gun used in question in the book was a heavily modified gatling cannon, and threw out explosive shells that detonated behind a bowl shaped pusher plate. so a conventional Project Orion type craft.
 
Top