Cheap open source orbital capable rocket

[Aghanim]

The idea is to make the rocket from materials you could by in your nearest hardware store, like this:

Fuel and oxidizer tank made from either sheet metal or fiberglass composite, fuel is diesel fuel or kerosene, oxidizer is liquid oxygen. Engine will be made from common metal, using pintle injector and piston pump, guidance using Arduino microprocessor and Sparkfun 6 DOF IMU, control using rollerons

Of course, with this low performance rocket, the only fitting payload is a Cubesat or some of it, but the point is everyone with some sort of machining tool could build it. And the design will be open source so everyone could build it. Hopefully, some workshop could be dedicated to build this rocket, reducing labor costs.

Now, is this possible?

Edited May 20, 2014 by Aghanim

[dharak1]

If you just want to launch a 1L cubesat then you would need something equivalent to JAXA's first orbital rocket. I recall reading somewhere on the forums it was their rocket that had a payload of 1Kg to orbit. I'm sure you could do it. Depending on how fast you want it done you might have to roll the dice and ignore the laws and such, but if you do it might be your only launch considering how difficult it is to miss an orbital launch. You can for sure build the control stuff from off the shelf components all you really need is one of those unlocked GPS units. For fuel I would go with kerosene. I would use something like this:

for a solid first stage, a hybrid for second because you can throttle it and get decent ISP and thrust and then a kerosene third stage because of efficacy.

[Winter Man]

Only problem with a reliable open source rocket is anyone with the proper tools could build it. North Korea, for example.

[Brethern]

Only problem with a reliable open source rocket is anyone with the proper tools could build it. North Korea, for example.

You know it's amusing how arrogant some people are, whose to say they don't already know how to build one?

[Streetwind]

Yes, it's called hobby rocketry, and a lot of people do it

Well, they do not launch cubesats, or even reach the Karman line - to do these things you need a license that hobbyists don't get (and for good reasons). You would also need a staged rocket - remember, this is Earth, not Kerbin, and you need close to 10 km/s dV to circularize in low earth orbit even with a perfectly flown gravity turn. And since the kinds of fuel you can buy at the hardware store are limited to around 200 Isp at most*, and single rocket stages are practically limited to just over 20x Isp in dV, there's no way whatsoever you're going to be launching a non-staged rocket anywhere close to space, even without payload. SSTO rockets don't actually work IRL.

*Hardware stores don't sell liquid oxygen. Cryogenic materials cannot be stored losslessly over time, even if the store owner wanted to pay the significant storage costs 24/7, 365 days a year. Your best bet is probably nitrous oxide and polybutadiene rubber, which lets you build a hybrid bipropellant rocket like the one Virgin Galactic is planning to use for their suborbital tourist flights. That mixture does around 180 Isp and gives you an engine that is throttleable, reasonably easy to handle and relatively cheap.

If you want to watch some guys build such a rocket, here's a video:

Keep in mind that, like all reality TV shows, this is fairly overdramatised. But it shows you roughly the upper bounds of what you can expect to achieve by bolting together a hobby rocket out of storebought materials.

As for serious, commercial launch services, there are/were quite a surprising number of small launch vehicles around. Look for example at the US Athena I rocket. 820 kg to LEO, also fueled by polybutadiene rubber - although as a pure-solid fuel with baked-in oxidizer, which simplifies the design and greatly increases Isp. But that's already not something you can get at the hardware store anymore, you need specialized fuel production facilities to make that stuff. Also, you can probably expect the rocket to have dedicated production facilities with bulk-ordered materials as well.

The need for these kinds of rockets isn't very large, though, considering how easy it is to launch cubesats piggyback on larger rockets. SpaceX for example just completed their CRS-3 resupply mission to the ISS for NASA... and also carried five cubesats along on the side, because they had a few kg worth of payload left that NASA didn't need. You can get these secondary payload slots extremely cheap if all you have is a cubesat, much cheaper than buying your own rocket, no matter how small it would be. And you get the benefit of riding on a reliable and highly sophisticated booster like the Falcon 9 instead of something someone glued together in his backyard.

Edited May 20, 2014 by Streetwind

[Comrade Jenkens]

In the UK all stages would have to be hybrid as building solid rocket motors get you charged with terrorism! Apart from that and it being at least 5 miles from houses and airfields (almost impossible in the UK) I think anything goes.

[Aghanim]

Hybrid is easier than liquid rockets, noted

But it seems that launch on existing boosters costs $40k... I starting to agree with Streetwind here

And no one is saying that this rocket won't be staged... but how do you create cheap decoupler? Is it even possible?

Edited May 20, 2014 by Aghanim

[astropapi1]

You might want to check out the N-Prize. These guys are gluing stuff together with bubble gum and duct tape, but they might just make it. Check out the "Wikisat" team in Youtube too. Bet you won't believe what their second stage is made of.

[sgt_flyer]

Well, for decoupling, most mechanical latches systems are simply too heavy / not reliable enough. So you'll need to be able to use explosive bolts - which uses pyrotechnic stuff, which are regulated almost everywhere.

[Aghanim]

You might want to check out the N-Prize. These guys are gluing stuff together with bubble gum and duct tape, but they might just make it. Check out the "Wikisat" team in Youtube too. Bet you won't believe what their second stage is made of.

Now I remember it!

The N-Prize is again accepting new teams. The Prize will remain open until it is won. Details in the revised Rules In Full.

And 2154 days has elapsed since the original deadline...

Now this makes me wonder. Assuming we successfully launch an object into space, how do we know that it is there? Orbiting Earth instead of going suborbital and falling again?

[peadar1987]

Well, for decoupling, most mechanical latches systems are simply too heavy / not reliable enough. So you'll need to be able to use explosive bolts - which uses pyrotechnic stuff, which are regulated almost everywhere.

Or hot stage with a polymer connecting structure that is structurally sound at ambient temperature will melt and fail when the upper stage is fired? Is that a possibility?

[Tommygun]

I would like to see someone take another shot at the Otrag system for something like this:

http://www.astronautix.com/lvs/otrag.htm

[Floppster]

Or hot stage with a polymer connecting structure that is structurally sound at ambient temperature will melt and fail when the upper stage is fired? Is that a possibility?

Copenhagen S used something like that for...Sapphire?... not sure about the rocket but the stages were tightened using some really strong rope that would melt and snap when the second stage ignited.

[cantab]

Now this makes me wonder. Assuming we successfully launch an object into space, how do we know that it is there? Orbiting Earth instead of going suborbital and falling again?

By the fact that it, y'know, doesn't fall.

[R0cketC0der]

Now this makes me wonder. Assuming we successfully launch an object into space, how do we know that it is there? Orbiting Earth instead of going suborbital and falling again?

We can measure its speed by comparing two different GPS measurements and the distance between them. From this speed, we can calculate its orbital parameters.

[sgt_flyer]

Or hot stage with a polymer connecting structure that is structurally sound at ambient temperature will melt and fail when the upper stage is fired? Is that a possibility?

It's a possibility, but you'll have to ensure that all of the connection points burn / separate at the same time. (Else your system might risk to pivot around the last remaining connection point (+ the thrust of the upper stage) fully destabilising the rocket

[Aghanim]

We can measure its speed by comparing two different GPS measurements and the distance between them. From this speed, we can calculate its orbital parameters.

GPS. Yes, I know we could use unlocked receivers to bypass ITAR restrictions, but still, for some reason measuring satellite speed by another satellite doesn't seems right. Is there any other way, like using radio or something?

[R0cketC0der]

GPS. Yes, I know we could use unlocked receivers to bypass ITAR restrictions, but still, for some reason measuring satellite speed by another satellite doesn't seems right. Is there any other way, like using radio or something?

Measuring speed with radio is possible, but if the rocket goes over the horizon before it completed its orbital injection, you will need multiple stations.

[cantab]

Yeah, if it's transmitting, plain old radio direction finding. Helps to have recievers in different places but not essential. Take a few observations and you can figure out the orbit.

Or, if it's big enough and reflective enough, optical tracking. Don't even think you'd need that fancy a telescope, though you'd want a fast-tracking and precise mount.

[Tex]

Can't give the link ATM, but you can make solid-state rocket fuel using potassium nitrate and sugar. Will try to provide link ASAP

[Aghanim]

R candy? I have tried to make it once but it failed to burn...

[YNM]

http://what-if.xkcd.com/24/

All using model rockets...

[christok]

R candy? I have tried to make it once but it failed to burn...

Careful with that stuff. There's a reason not all amateur rocketeers have ten fingers.

[Tex]

Careful with that stuff. There's a reason not all amateur rocketeers have ten fingers.

Aw, please, don't lecture me on- *boom*

[astropapi1]

*Sigh* Why do I always have to be the guy who revives threads?

Here's Wikisat's second stage:

[spoiler=]

Their satellite masses less than 20g

Combined with a high altitude balloon, it shouldn't take that much to put it in orbit. What I don't understand is their guidance system. I remember reading something about using the earth's magnetic field to rotate the spacecraft, but is it enough to guide a rocket? What kind of alternatives are there for such a small engine?