Amateur rocket to orbit

[Hesp]

@wumpus Basically you need the know-how. To build that you need engineering time, prototypes, measuring lab and testing equipment, and failures. Lots of them. Any failure you investigate correctly gives you further knowledge of the topic.

Building a system that works at the first attempt without having previous experience and know-how is pure luck.

 

On a side note, that's why every aerospace supplier must have a AS9100 or EN9100 certification. 

Edited August 26, 2017 by Hesp

[Exoscientist]

 Two possibilities,

one liquid fueled:

Orbital rockets are now easy. 
https://exoscientist.blogspot.com/2015/08/orbital-rockets-are-now-easy.html

the other solid-fueled:

Orbital rockets are now easy, page 2: solid-rockets for cube-sats. 
https://exoscientist.blogspot.com/2017/08/orbital-rockets-are-now-easy-page-2.html

 

 Bob Clark

[cubinator]

Misread as "Amateur rock to orbit" and thought "yeah, that's doable."

[wumpus]

On 8/26/2017 at 9:42 AM, Exoscientist said:

 Two possibilities,

one liquid fueled:

While I can't take the "easy" seriously, I can't believe that I don't remember fuel (well, oxidizer) cross-feeding coming up in this thread.  Most of the reasons I'm aware of crossfeeding not being used involve the pickiness of turbopumps (as noted above, just building them is hard enough.  Although I'm shocked silly that crossfeeding *restartable* pump-fed engines is such a problem, perhaps the start/stop sequence keeps them off long enough to lose all efficiency gained from the crossfeeding). 

Of course there will be issues in that during the entire "changing between oxidizer tanks" output pressure *never* drops to the point that the flames/pressure/heat return back through the oxidizer plumbing, but it is presumably worth it to have oxidizer cross-feeding (or both fuel and oxidizer if using both).

[Exoscientist]

On 7/9/2017 at 3:25 PM, sevenperforce said:

Unless I recall incorrectly, HTP can be synthesized and distilled with a fairly small lab setup.

Also, to an earlier point -- we should be thinking less about "increasing payload" and more about actually ensuring we can get our rocket into orbit.

What single-stick target TWR should we have? 2? 3?

White Lightning can go as high as 214 seconds. Definitely a good kick-stage choice.

 

  These solid motors also have very high thrust/weight ratios in the range of 25 to 50 and above. Good for reducing gravity drag but bad since this increases air drag.

 

    Bob Clark

[FleshJeb]

@wumpus That was a great link to the DARPA paper on Nitrous Oxide/Propane rockets. (Re-linked, since it's a ways back.)

Benefits:

• Common, safe fuels
• Decent Isp
• Pressure-fed (Good link @Exoscientist)
• Throttleable
• Self-igniting
• Ability to cross-feed
• Already bench-tested

I'm envisioning a 3-stage non-recoverable serial stack:

1. NOP*4 - Differential throttle control. Need cross-feed to ensure that the fuel is balanced.
2. Identical, single NOP with altitude-optimized bell and RCS control.
3. Payload and guidance + Solid motor with carbon-fiber shell.

The 5 NOP cores are identical except for the engine bell. The RCS blocks can go on top of stage 2. Maybe altitude-compensating on the first stage.

Launch stages:

1. Full throttle to g-limit and/or Max Q
2. Full throttle to g-limit. Orient and spin-stabilize with the RCS on the coast to Apo.
3. Fire solid at Apo.

[DerekL1963]

9 minutes ago, FleshJeb said:

• Identical, single NOP with altitude-optimized bell and RCS control.
• Payload and guidance + Solid motor with carbon-fiber shell.

 

9 minutes ago, FleshJeb said:

• Full throttle to g-limit. Orient and spin-stabilize with the RCS on the coast to Apo.
• Fire solid at Apo.

Seems to me you could put the guidance on the second stage.  That way you could either get better performance out of the third, or for the same payload reduce the weight of the third to increase the performance of the overall vehicle.

[FleshJeb]

14 minutes ago, DerekL1963 said:

Seems to me you could put the guidance on the second stage.  That way you could either get better performance out of the third, or for the same payload reduce the weight of the third to increase the performance of the overall vehicle.

That's an excellent idea.

I think we could get more mileage out of making the third stage non-solid. However, that would require developing another core, and small solids are robust and commercially available.

The guidance system I envisioned uses the payload camera as a sun or moon tracker. With some mirrors and some software, you could specify an offset angle to the light source that changes throughout the trajectory. Fairly similar to how heat-seeking missiles work today.

[DerekL1963]

9 minutes ago, FleshJeb said:

The guidance system I envisioned uses the payload camera as a sun or moon tracker. With some mirrors and some software, you could specify an offset angle to the light source that changes throughout the trajectory. Fairly similar to how heat-seeking missiles work today.

That's a pretty sophisticated system - and it may lock you into a single payload and a dead end program.  That's certainly a valid choice, but one that should be made deliberately rather than bumping into it by accident.

[FleshJeb]

3 minutes ago, DerekL1963 said:

That's a pretty sophisticated system - and it may lock you into a single payload and a dead end program.  That's certainly a valid choice, but one that should be made deliberately rather than bumping into it by accident.

Agreed on the payload.

I disagree that it's sophisticated. Certainly less than inertial guidance. A dual-axis solar tracker with 4 photodiodes can be built as a completely "dumb" system for <$10.  Even if the tracking system is a bit more sophisticated than photodiodes with strategically-placed shades, the algorithms and math are already well-developed.

Hmm, I'm sure I could figure out a way to do one out of a side window on the rocket that could compensate for launch latitude, time of year, and time of day of launch.

 

[DerekL1963]

1 hour ago, FleshJeb said:

A dual-axis solar tracker with 4 photodiodes can be built as a completely "dumb" system for <$10.

Accurate to arc minute tolerances and capable of withstanding the vibration and acceleration of a launch with an acceptable (.95+ at a minimum) degree of reliability?  Just because the concept is simple, that doesn't mean the design and execution is equally simple.

The algorithms and the math are the easy parts.  The hardware is the hard part.  The hardware is almost always the hard part.

[FleshJeb]

2 hours ago, DerekL1963 said:

Accurate to arc minute tolerances and capable of withstanding the vibration and acceleration of a launch with an acceptable (.95+ at a minimum) degree of reliability?  Just because the concept is simple, that doesn't mean the design and execution is equally simple.

The algorithms and the math are the easy parts.  The hardware is the hard part.  The hardware is almost always the hard part.

I see, we misunderstood each other. I'm not suggesting sticking a $10 guidance system on a $100k rocket (it would be paired with an inertial guidance system, as well), but rather something simple, robust, and "good enough". Of course it requires high tolerances, but I don't think a single arc-minute is necessary. As long as the periapsis gets comfortably above the Karman line, I should think that's good enough.

Which brings us to another point: We could simply slap a commercially available INS on this thing and call it good. What's our balance between innovating and just doing systems integration of commercial (COTS) parts? Systems integration IS a tough and worthwhile subject...

[DerekL1963]

1 hour ago, FleshJeb said:

I see, we misunderstood each other. I'm not suggesting sticking a $10 guidance system on a $100k rocket (it would be paired with an inertial guidance system, as well), but rather something simple, robust, and "good enough". Of course it requires high tolerances, but I don't think a single arc-minute is necessary. As long as the periapsis gets comfortably above the Karman line, I should think that's good enough.

Ah, that happens.  I'm with you on simple, robust, and "good enough".  But what constitutes "good enough" also depends on what's acceptable to the relevant regulatory bodies.  We're not going to orbit from any first world country without a launch license.

Though if you have an inertial system...  why do you need a sun tracker in the first place?
 

1 hour ago, FleshJeb said:

Which brings us to another point: We could simply slap a commercially available INS on this thing and call it good. What's our balance between innovating and just doing systems integration of commercial (COTS) parts? Systems integration IS a tough and worthwhile subject...

An amatuer effort is generally stuck in a strange place...  Not enough money for pro gear, but often also not enough money for a R&D program to develop a suitable replacement on a reasonable timeline.  And almost never enough for "innovation".

[wumpus]

While the vacuum Isp of propane and N₂O isn't that bad, I'm less convinced of the sea level performance.  It might need some boosters.

I wouldn't underestimate what a photodiode can do.  A quick check of digikey showed plenty of photodiodes that wouldn't be a limiting factor, and a cheap and available had 7.5ns response (it should be higher than you sampling rate needed to filter out the vibrations, actual change in position is trivial compared to that).  I'd expect an array of much more than 4 would be needed (wait till the lens/canopy warps due to maxQ pushing it around).

I strongly suspect that off the shelf options are out of reach, unless they are some sort of side-hobby of the manufacturer.  The volume for this type of thing is just too low.  I imagine the huge issue would be getting something that would naturally filter/accumulate the vibrations that happened in each sample (further filtering isn't hard, but you really need good samples:  you could combine analog filters with fairly high sampling and have great data from those photodiodes).  I'd be more concerned with trying to do avionics at high vibration, perhaps you would have multiple engines and throttle the oxidizer in a specific direction.

I suppose I've heard of a few launches exploded due to guidence failures, but even more engine failures.  I'm curious why Copenhagen Suborbitals remain "suborbital", and I'm guessing mainly cost.  On the other hand, their main goal is human flight, and launching a satellite really doesn't help much that way (they really don't  intend to put a person in orbit any time soon, thus the name).  It really looks like they are as close to getting to orbit as Korelev and von Braun were in 1955 or so.

[Edit] Scott Manley just released a video: "10 dump space mistakes".  Plenty of them were guidance errors, but I suspect a lot of that has to do with Scott being a software developer and knowing "how hard could that be" and also knowing that such software is typically the proverbial straw that breaks the camel's back.  Still, I'm more familiar with engine/staging failures than guidance errors causing rockets to fail/explode/be exploded for range safety.

Edited September 19, 2017 by wumpus
after [edit]

[quasarrgames]

I'm not sure if this has been mentioned before, but for side/lower stage boosters, a propellant like ALICE might be effective. The fuel seems incredibly easy (and a bit safer) to make compared to the other fuels discussed here. In addition, the Isp of the propellant seems to get drastically better with the size of the booster. For a respectable 1ft diameter booster, i'd suspect an Isp of 250s could easily be achieved. The only major drawback seems to be that a large amount of spent fuel seems to want to stay inside the rocket after combustion, but i suspect that this is simply because little research has been done into optimizing its fuel flow. 

In addition, how small could the payload be reasonably made in order to still communicate with earth? Several kilograms of payload seems a bit heavy. 

Finally, i don't mean to beat a dead horse, but how much money would this "amateur" rocket be expected to cost? A few thousand? A few hundred thousand? A few million?

[Riven]

11 hours ago, quasarrgames said:

Finally, i don't mean to beat a dead horse, but how much money would this "amateur" rocket be expected to cost? A few thousand? A few hundred thousand? A few million?

It would be at least in the high six figures, seven if you're going bipropellant with turbopumps. Be prepared to ask executives of companies in person to sponsor you.

Source: VP of operations for a space exploration org at my university. Our current flagship project is for the FAR-Mars competition. TL;DR for competition description: you fly an unguided liquid methane fueled rocket with 1 kilo payload to as close to 45,000 feet as possible, and we have until May 2018 to put something together that flies. We've done a lot of the theoretical calculations so far, and we have designed the engine already, but guess why we can't do testing and manufacturing yet? Money. We estimated that this rocket - including GSE, ground station electronics, custom fabricated test stands, test equipment - will cost us upwards of $60k. The engine itself would cost $15k to 3D print out of Inconel 716. It would be 3D printed because drilling extremely long and thin regenerative cooling channels into the thin, curved walls of a small methane fueled engine is probably impossible. While most of our efforts are focused on continuing to design, the president and I are organizing business majors to go to companies in person to attempt to get funding (or even spare rocket parts). We had limited success with Cryoquip, Inc. when we talked to them in person over the summer for example - they were extremely excited to design high pressure composite cryogenic tanks for us - but they got some LNG deal in South Korea recently and they dropped our project.

I skimmed through this thread and saw something about using turbopumps. If you can shell out tons of money for the manufacturing of it, then sure. We considered turbopumps over our helium pressure-fed system for a week, but after realizing the engineering required for the complexity of designing and manufacturing one, we elected to use a helium pressure fed system pressurized to 15Mpa.

We intend to apply what we learn building (and hopefully launching) this rocket to design an orbital cubesat launcher over the span of a few years because we need research, experience, and money/sponsors with operating something like this, and who knows, another university with extremely deep pockets (cough Purdue, USC, etc) could beat us to it by then.

12 hours ago, quasarrgames said:

In addition, how small could the payload be reasonably made in order to still communicate with earth? Several kilograms of payload seems a bit heavy.

1U cubesats - 10x10x10 cm. These can be as light as 1 kilo. If you have a highly directional VHF/UHF antenna and the right radio equipment, you can communicate with one in LEO.

[Steel]

10 hours ago, Riven said:

It would be at least in the high six figures, seven if you're going bipropellant with turbopumps. Be prepared to ask executives of companies in person to sponsor you.

Source: VP of operations for a space exploration org at my university. Our current flagship project is for the FAR-Mars competition. TL;DR for competition description: you fly an unguided liquid methane fueled rocket with 1 kilo payload to as close to 45,000 feet as possible, and we have until May 2018 to put something together that flies. We've done a lot of the theoretical calculations so far, and we have designed the engine already, but guess why we can't do testing and manufacturing yet? Money. We estimated that this rocket - including GSE, ground station electronics, custom fabricated test stands, test equipment - will cost us upwards of $60k. The engine itself would cost $15k to 3D print out of Inconel 716. It would be 3D printed because drilling extremely long and thin regenerative cooling channels into the thin, curved walls of a small methane fueled engine is probably impossible. While most of our efforts are focused on continuing to design, the president and I are organizing business majors to go to companies in person to attempt to get funding (or even spare rocket parts). We had limited success with Cryoquip, Inc. when we talked to them in person over the summer for example - they were extremely excited to design high pressure composite cryogenic tanks for us - but they got some LNG deal in South Korea recently and they dropped our project.

I skimmed through this thread and saw something about using turbopumps. If you can shell out tons of money for the manufacturing of it, then sure. We considered turbopumps over our helium pressure-fed system for a week, but after realizing the engineering required for the complexity of designing and manufacturing one, we elected to use a helium pressure fed system pressurized to 15Mpa.

We intend to apply what we learn building (and hopefully launching) this rocket to design an orbital cubesat launcher over the span of a few years because we need research, experience, and money/sponsors with operating something like this, and who knows, another university with extremely deep pockets (cough Purdue, USC, etc) could beat us to it by then.

1U cubesats - 10x10x10 cm. These can be as light as 1 kilo. If you have a highly directional VHF/UHF antenna and the right radio equipment, you can communicate with one in LEO.

Welcome to the forums!

That's a really nice summary, echoing what some of us have been saying earlier in the thread. Your project sounds really interesting (I wish there had been something like this at mine when I was there) do you mind if I ask what university you are a part of?

[wumpus]

13 hours ago, Riven said:

It would be at least in the high six figures, seven if you're going bipropellant with turbopumps. Be prepared to ask executives of companies in person to sponsor you.

 We estimated that this rocket - including GSE, ground station electronics, custom fabricated test stands, test equipment - will cost us upwards of $60k. The engine itself would cost $15k to 3D print out of Inconel 716. It would be 3D printed because drilling extremely long and thin regenerative cooling channels into the thin, curved walls of a small methane fueled engine is probably impossible.

And this is for [scribbles using equations unused for decades] 500m/s delta-v?  There's a reason that Copenhagen Suborbitals hasn't put anything into orbit (even though they are working with turbopumps).  Are you making a big deal about guidance systems (plenty here assume it is critical)?

* For 45,000 feet, I'd rather use a weather balloon.  If there was ever a reason for balloon-launch, this is it.  I suspect that launching at 30,000 and trying to get 75,000 feet would be easier.  Or possibly 73,000 feet thanks to Edward's elevation (since the rules state two liquid fuels).

[Riven]

2 hours ago, wumpus said:

And this is for [scribbles using equations unused for decades] 500m/s delta-v?  There's a reason that Copenhagen Suborbitals hasn't put anything into orbit (even though they are working with turbopumps).  Are you making a big deal about guidance systems (plenty here assume it is critical)?

Zero guidance systems allowed, otherwise we would be violating ITAR. As long as the center of pressure is below the center of mass, it'll fly straight given our fins are installed straight and the launch rail is straight. But for altitude control, we're gonna throttle the engine (won't give specifics on how until competition is over), which doesn't fall under guidance systems. And yes we're working with roughly 500m/s.

For 45kFt ASL, that's the altitude we're trying to achieve - it has to be launched from the ground. Due to FAA restrictions on the site for that day, we can't fly above 50kFt and we have to achieve at least 30kFt to qualify.

6 hours ago, Steel said:

Welcome to the forums!

That's a really nice summary, echoing what some of us have been saying earlier in the thread. Your project sounds really interesting (I wish there had been something like this at mine when I was there) do you mind if I ask what university you are a part of?

Thank you!

Thanks! I attend SJSU, and I'm interested in electrical propulsion, specifically gridded ion thrusters and MPDTs.

[BillKerman1234]

Is anyone still using this thread?

[BillKerman1234]

A few years ago this thread started.

It looked at what it would take to get an amateur built rocket into orbit, and over time it evolved into a full blown feasibility study, and we got a few really good ideas and designs, along with some really good conversations, until late 2017, when it suddenly stopped. I was wondering if it would be a good idea to restart the thread again, and see if we can continue trying to come up with a rocket design that, one day, might actually get built. (Oh, and just for the record, I didn’t actually participate in the original thread, but I did read all of it)

Since no ones touched on this in a while, I’ll start off the conversation.

The consensus of everyone on the rocket design was to have ether a single core with 4 boosters and a upper kick stage, or, if that didn’t have enough delta v, 4 cores and 4 boosters with the same upper kick stage. The cores and boosters would be identical, using fins to steer in the atmosphere, while using RCS to steer in vacuum. The motors would be hybrids, running of a propellent that most people agreed would be some sort of htp/gasoline (I think). The RCS would be built into the core, and the side boosters would use the empty holes where the RCS would be on the identical core stage to mount gas thrusters to act as sep motors. The boosters and core would be recovered with parachutes. The upper stage would be a cluster of ether solid or hybrid motors. For simplicity it would have no guidance system other than gyros and accelerometers.

Some people also suggested air launch from a ballon, but this was generally thought to be to complex.

I propose that we use the same first stage design, and the boosters, but switch out the second stage to be a (very small, like just slightly larger than RCS sized) liquid engine running on ether methane/lox, gasoline/lox, or alcohol/lox (We could machine it with a lathe). It will be capable of thrust vectoring using simple hydrolic pistons to move the engine, and the fuel lines will be ether rubber tubes (which might turn brittle in space) or segmented plastic/metal tubes. The payload will be a cylinder covered in simple solar cells, (you can get them very cheaply on Amazon, though if they’ll survive space I’m not sure) and will contain ether a RPi or an arduino for control, with a series of accelerometers and mangatorquers for direction control. It would also have a very basic thruster (maybe ion? Check this out: https://m.youtube.com/watch?v=_TYvUdaLjRA, otherwise it could just be a CO2 cartridge with a valve) for station keeping.

I’ve included some diagrams of the proposed rocket, and some calculations for it.

As for cost, if we use standard aluminium sheets that we bend and weld into cylinders for the fuel tanks, and if we keep everything cheap enough, we could probably do it for 20k to 50k (maybe).

Anyway, I hope that we will get some good conversations, ideas, and designs from this, and maybe, one day, someone will actually try to build it!

 

Edited September 11, 2018 by BillKerman1234

[Vanamonde]

That was not "a few years ago" but one year ago, so why not continue the original thread to keep the discussion all in one place?

Overlapping threads have been merged. 

[BillKerman1234]

Oh wow, I didn’t expect a reply so quickly! Also, forgive me for being rude, but is anyone from the original thread still here (other than the moderators)? It’s just that no ones posted in half a year. Do you know why?

[James Kerman]

Welcome to the forum, @BillKerman1234.

Many members (Including the thread originator) are still active on the forum.  Some threads go dormant for a while, until they are brought back into the community consciousness by new ideas, such as your post.  It's not uncommon for threads on space missions to go quiet after launch until the probe gets to it's target location - which can be a long time depending on the destination.

[Mad Rocket Scientist]

I understand gasoline to be a bad fuel compared to alcohol. As to ITAR: what are the rules in other countries? Does copenhagen suborbitals have to deal with the local equivalent of ITAR there?