Catapults
In Spaaaaaaaaaace!
An electromagetic catapult is a pretty simple thing.
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I built one when I was but a lad from a length of plastic pipe and some wire. I used it to shoot nails
Mom did not approve.
On a somewhat larger scale the latest AirCraft carriers are installing them instead of the old SteamPowered Cats.
The USS Gerald R. Ford (CVN-78) Aircraft Carrier has one.
Why put one in orbit?
The simple answer is Fuel.
Rockets use a LOT of fuel.
SpaceX's Falcon heavy, that sent starman in the little red roadster toward the asteroid belt, for example, has a launch weight of 1394 tonnes. Most of that is fuel. The payload to low earth orbit is only 28 tonnes, it cost 350,000 pounds sterling to refuel and it can only be used ten times.
The second stage is mostly fuel too. LOTS of (very expensive) fuel is required to get something into orbit and even more is needed to go anywhere else. Like the moon, mars, or the asteroids.
An orbital electromagnetic catapult would avoid all that.
Imagine a YUGE cat. Many, many times longer than that on the USS Gerald Ford. In fact there is really no limit to how long it could be. Think miles, or tens of miles long. A hyperloop in space.
It could be powered by sunlight.
- At the upper reaches of our atmosphere, the energy density of solar radiation is approximately 1,368 W/m2 (watts per square meter) That's about two horsepower per square yard. Once again..there is no real limit to how big solar panels can be made....square miles perhaps?
That's all 24/7 forever.
Imagine how much could be accumulated in super-capacitors to be used to launch?
But WAIT..there's more.
Low Earth Orbit (LEO) isn't very high. That's why it's called LOW. LEO sattelites, like the International Space Station almost skim the atmosphere. In fact that's why the Chineese space station crashed the other month. Atmospheric drag.
But they have to go FAST to maintain orbit. 24,000 miles per hour fast.
Well imagine that a payload was launched at 24,000 mph in the opposite direction.
It would just be sitting there. Not moving anywhere...about 200 miles up.
No need to 'burn off' orbital speed.
Of course it would stay there but for an instant before it started to fall. Gravity is like that..
So.
The Roton.
So here's the deal.
Build a YUGE solar powered electromagnetic catapult in low earth orbit. Use it to provide the excape velocity for trips to...anywhere. If/when asteroid mining commences some of the materials from the asteroids (refined in space) could be used to make a one-use Roton re entry vehicle. Use it once and throw it away. (of course the material would be recycled)
Or...use a parachute.
Easier but not as cool.
This is an extra fun post with even more fun added in comments...
I'm a mechanical engineer and you schooled me on some things.
thank you.
I'm a retired trucker.
Truckers know everything about everything.
Just ask one.
But all seriousness aside.
Rockets are 'self propelled' (duh) and autonomous.
No reason to settle for that.
Build 'infrastructure' which doesn't require onboard propulsion.
That'd save a bunchaton of weight that could be used for payload.
You would still need a propulsion system, I recommend an Ion drive. This is because when you shoot a parcel from a catapult, the catapult will see an equal and opposite reaction.
A small ionic thruster could restore the catapults orbit, with a minimum fuel expenditure using a solar power source; to stabilize it, after each shot.
:Dwell yeah.
In reality there would be a lot of 'fiddly bits'
Remember the 'equal but opposite reaction' though.
Anything 'incoming' would increase the velocity, if it used the 'catapult' to slow down.
It might be possible to balance the in coming and out going somewhat
If you are off, even by a small amount over interplanetary distances, the catch could get dangerous. But the whole system is fascinating. :)
well yeah..precision is important.
Always is for sure! If you combined an orbital elevator with one of these, the entire game changes.
:)It occurs to me that we may have made a mistake.
consider.
If an orbit-to-earth pod is launched via electromagnetic catapult...it will tend to increase the orbital velocity of the launch facility (space station)...will it not?
Absolutely, slow the package, speed the catapult. That is why we need the ion drive, very low thrust, but uses almost no reaction mass (fuel) to restore stable orbit.
or an orbital pinwheel, or an array of orbital pinwheels, or a combination of many systems.
'rockets are wrong' according to a character in a SF book I once read.
There are a bunchaton of alternatives...but they're not vehicles. They're 'infrastructure'
....So can I come to you, to ask for advice on changing fuses then?
😂😂
I use circuit breakers.
I use something.. something....got ya.