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Civilian Astronauts
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You are currently reading a thread in /sci/ - Science & Math

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Has anyone ever been able to create their own rocket which was able to launch something into orbit or beyond? I'm talking like trying to launch something to the moon.

If not, how feasible is this with no access to highly controlled materials (i.e. rocket fuel, guidance system, etc.)?

What would happen if you were caught (international laws against this)?

I figured that I would ask /sci/
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>>6850861
When I was younger, we fooled around with model rockets and what not, never got more than that though. What are you launching? Just the rocket itself or did you want anykind of payload? Getting into orbit would be much easier than getting to the moon since you would have to figure out aim/traj. and probably need a way to make adjustments one you launch.

Probably feasible to do with off the shelf stuff though, as long as you get someone to fabricate your stuff (engineer).

No idea for legal issues, but will monitor out of interest.
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>>6850861

yeah, weather balloon.
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>>6850869
you can't take a weather balloon to the moon.

>>6850866
what makes it so much harder to get to the moon as opposed to into orbit? escape velocity?
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>>6850866
if you were to launch a rocket with say, a Q class rocket engine at 100 000 ft if you got it up there, would it have any more of a chance of achieving orbit? What kind of engine/thrust is necessary?
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>>6850861
SpaceX is a civilian company which does actually do orbital launch.

For a hobbyist to do orbital launch on their own time, however, would be a huge task.

>>6850885
It is a problem of velocity, yeah.
See, in space, "distance" isn't really a factor. Space is frictionless - you can coast from any point in space TO any point in space with even the slightest impulse.
The problem is velocity. Your orbital trajectory is dependent on how quickly you're going, and if you want to actually go somewhere, you don't just have to be in the same place, you have to be going the same velocity in the same direction.

Earth orbit is about 9.4 km/s of velocity-change away. (Taking into account the velocity you lose pushing against drag.)

Getting from Earth orbit to Moon orbit is another 4.8 km/sec of velocity change, and getting from Moon orbit to actually sitting stationary on the Moon's surface is another 1.6 km/s.

So to get to orbit you just need a rocket big enough to get the payload into orbit - to get to the Moon, you need a rocket big enough to get a whole 'nother rocket with the payload in it up to speed.

And orbit's already juuuuust on the edge of what a hobbyist could feasibly do (to the point where no hobbyist has done it yet). An orbital rocket big enough to take not just the payload, but another, smaller rocket? Far beyond hobby capacity.
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>>6850861
Amateur Rocketeers can barely get a rocket above the Karman line every now and then. By the time the rocket gets to that altitude it's approaching apogee and effectively not moving. To get into a semi-stable orbit, it would have to fly up to an altitude four times higher and then accelerate up to a speed of 17,500 MPH, or around mach 23. Achieving Earth orbit would be REALLY hard with limited resources, government restrictions, and a one-man work force. And even with a team of people, just look at North Korea. If you did manage it, you'd end up with something about the size of a Falcon 9, a 200 foot rocket weighing in at around a million pounds. I've actually given this a lot of thought and I've concluded that it really isn't feasible.
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>>6852183
>If you did manage it, you'd end up with something about the size of a Falcon 9, a 200 foot rocket weighing in at around a million pounds.
...which can take a 20-ton payload to orbit, or send 13 tons to orbit and then land the first stage back on Earth.

You don't need anything near that size if you just want to go to orbit. Studies have been done showing that orbital rockets could be done in a few hundred pounds. They'd just have very small payloads.

Getting permission is harder than getting to orbit. And yes, you'd be in a lot of trouble if you just broke the rules and got caught.
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>>6850861
No

Impossible

Idk, don't think there are any
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>>6850861
Not impossible. Amateurs have launched suborbital unmanned flights, scaling up is a matter of money. In terms of laws you should be good as long as you don't smuggle hardware accross borders.

In terms of controlled materials, you'll run into problems with solids but should be fine with liquids. N2O and O2 are availible oxidizers, with H2O2 as an option (but is illegal above a certain concentration in the UK).

In terms of guidance, you'll run into problems with 'cocom limits' (commercial gps receivers shut down above a certain altitude and velocity to stop you from using it for an ICBM for best Korea and such).

Goodluck, space Anon.
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>>6853309
Do you know of any literature which would help me get into orbit?

Any way to hack or diy own tracking system so that the gps won't cut out?
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>>6850861
check out copenhagen suborbitals
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>>6854228
Basic physics first. If you can't answer the questions you've already posed in this thread, then you have no business building orbital rockets.

Join a local rocketry club in your area. That will give you some hands-on experience.

>>6854256
They are cool guys, but are only aiming at suborbital hops to the Karman line (100km)

>>6850861
The smallest orbital rocket so far has been Japan's Lambda-4 (16.5 m long). Also Britain's Black Arrow (13 m, but 2m thick). The smallest design is Indonesia's RPS-420 (9.5 m), but they ran out of money to build it.

Seriously, if an entire country can't afford to make an orbital rocket, what makes you think an individual can?

And don't even ask about international regulations... breaking the law and going to jail are the least of your worries.
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>>6854612
They were trying to make a rocket tThe carry satellites to space. We just need one big enough to carry a single nanosatellite.
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>>6854619
no, those were all for nano-sats (about 50kg), so near the theoretical lower limit for size.

Another small launcher will have a debut early next year. The American Super Strypi or SPARK is 16.8 m long, has a payload of 300kg and will be launching from Hawaii.
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>>6854612
The Lambda-4 was designed to deliver a 26 - kg payload to orbit. We only need a tiny, tiny payload - a nanosat, say, at 1.33 kg. That suggests that our orbital rocket - keeping the same design - could be about 6 meters tall and 0.3 m diameter.

In size, at least, that's about as big as the largest amateur rockets. The Lambda even used solid fuel, which is within hobby capability.

The difficulty is in the staging, which is really, really hard to do reliably. Even the Lambda 4 failed 4 out of 5 launches.
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>>6854626
Sorry; I didn't realize "nanosatellite" was a general term. I thought it referred to CubeSats specifically, which are 1.33 kg, 10 cm cubic satellites accessible to hobbyists.
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There was that one movie. Astronaut farmer or something.
Doubt it was really grounded in reality, but it was nice to watch ether way.
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>>6854646
>6 m
Check your calculations, that isn't right. Even multistage sounding rockets aren't that small.
At least show your work: the mass, altitude and delta-V you think each of your stages attains.

Staging isn't so bad compared to trajectory control. That is a problem that gets harder as the rocket gets smaller.
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>>6854663
I used the laziest possible calculation.

To maintain the same delta-v, the rocket needs to have the same mass ratio. Because payload mass is 19.5 times smaller - 1.33 kg as opposed to 26 kg - rocket mass is 19.5 times smaller as well. Assuming similar density, that means rocket volume decreases by 19.5, so that's equivalent to a decrease in scale of about 2.7. So diameter shrinks by a factor of 2.7 to get about 0.3, and length shrinks to about 6.

It's a rough estimate, nothing more.
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>>6854626
>those were all for nano-sats (about 50kg), so near the theoretical lower limit for size.
But that's not near the theoretical lower limit for size. It's near the practical lower limit for governments to think it's worth doing, and to think it's a meaningful step toward a much larger launch vehicle, which is how they generally view it.

It's definitely possible to make an orbital launch vehicle under 1 ton, however, you can't scale down existing technology, or expect to scale up what you've made. When you go that small, you need a scale-specific design.

Setting aside all regulatory concerns, if I were making a tiny launch vehicle, I'd start with a turbojet-powered UAV stage. Basically a model White Knight powered by big RC jet engines. You can put that together with off-the-shelf parts.

Then I'd go with proven high-power rocket motors. Something amateurs are already playing with regularly, that also won't require a development effort or give you nasty surprises. You might need two stages with them. The point is a boost out of atmosphere. You can get up the speed you need for this while you're still steering with fins, so you don't need to get too clever.

These first two parts you can get just with money and with recruiting hobbyists who would love to do it. You can start testing this before developing the upper stage.

The next part is somewhat harder. If you're not aiming at a particular orbit, you can probably just steer with cheap solid-state gyroscopes. However, to get to orbit, now you're going to need good specific impulse with low empty weight and adequate thrust, and you're going to need a way to stay pointed in the right direction without using fins.

This is like nothing else. Now you're doing spaceflight, and you can only get practice at it in accurate conditions with costly booster flights. So you've got to practice thrust-vectored flight in the atmosphere. A flight-weight lunar lander would develop the necessary capabilities.
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>>6854678
Nope, you can't scale stuff linearly like that, for many reasons. One, the rocket equation is exponential. Two, motor casings need to keep the same thicknesses even if shrunk. The smaller you go, the worse your mass fraction because of that.

Rocket science is a bitch.

There are some tools you can play with to get a feel for the problems. Try looking for OpenRocket.
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>>6854751
>One, the rocket equation is exponential.
You don't understand this shit at all. The rocket equation is exponential with regard to delta-V, but it's linear with regard to payload.

>Two, motor casings need to keep the same thicknesses even if shrunk.
Also completely wrong. For a fixed pressure, the mass of a pressure vessel is proportional to the volume contained. When you double the volume, you double the mass of the pressure vessel.

So that's two things that are each scale-invariant.

There are scaling issues, but these are not some of them.
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>>6854751
I'm aware the rocket equation is exponential. Dv = Ve ln (mass ratio). If Ve is constant, and mass ratio is constant, then you get the same Dv.

I was assuming the rocket mass was mostly propellant, so scaling down payload mass would allow you to scale down rocket mass proportionally and keep the same mass ratio. Ofc, if the rocket is not mostly propellant, this doesn't work, but it seemed a decent guess for a first approximation.

Or am I misrembering the rocket equation?
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>>6854763
I'd assume that the main issue is aerodynamics. I know nothing about the subject, but I'm pretty sure that air scales nonlinearly.
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>>6854774
Yeah, that's a big problem, and one reason air launch is favored for small orbital launchers.

Another one is "minimum gauge" (you can't buy and effectively work with sheet metal beyond a minimum thickness), which is one reason very small liquid-fueled rockets tend to be pressure-fed.

There are also efficiency considerations with small rocket engines. You may need a larger combustion chamber to get complete combustion. With very large rocket engines, the combustion chamber starts to become difficult to distinguish from the nozzle: there is little or no neck between them, which improves their mass efficiency. Then there are fluid dynamics issues with small tubes. None of this stuff scales simply.
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One of the ways you can deal with the aerodynamic scaling factors is simply to ascend more slowly.

You can do a rocket-powered subsonic ascent out of atmosphere. The great thing about this is that the challenge is very similar to the challenge of getting to orbit. You need good mass fractions and precise control, yet you're not spending any development effort dealing with the aerodynamic issues of supersonic and hypersonic flight.
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>>6854751

>Nope, you can't scale stuff linearly like that, for many reasons. One, the rocket equation is exponential.
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