10 ms·

Build Your Own Thrust Vectored Rockets for Vertical Landings Like SpaceX

457 points by gscott 7y ago

stwr 7y ago
Been a big fan and supporter of Joe's work for a long time, really amazing work he is doing and how open he is about it, sharing lots of his knowledge in the BPS.space discord. Great to see him on the front page!
- Sendotsh 7y ago
  He’s such an inspiration. Zero background in any of this and just went “This looks cool, I’m going to figure it out”. His videos are incredibly entertaining and educational too.
gridspy 7y ago
If you want a quick video overview: "BPS.Space - Channel Trailer - 2019" https://www.youtube.com/watch?v=OE0_-g7YV1M https://www.youtube.com/watch?v=OE0_-g7YV1M
jiofih 7y ago
The Falcon Heavy model launch is one of the funniest and inspiring things I’ve seen: https://m.youtube.com/watch?v=ff5245EBfis https://m.youtube.com/watch?v=ff5245EBfis
- JoeAltmaier 7y ago
  Awesome you mean! Even when it doesn't work, it's doing something amazing. Somebody buy this guy a Red Button, he deserves it.
anovikov 7y ago
Trick of SpaceX success wasn't in vertically landing rockets - with mass being concentrated in the bottom in form of engines, thrust structure, and legs, it's not all that hard. What was extremely hard, is havigation and control to enable return back to launch site optimally, going through narrow corridors of acceptable parameters (go too shallow and you risk being unable to correct your position in the end as precision drops, go too steep and rocket breaks up due to aerodynamic forces, and so on), while burning minimum fuel. That was an insanely difficult GNC task which took so many iterations to perfect out... Plus yes, on landing they didn't have a second chance as rocket couldn't hover - minimum engine thrust was bigger than it's mass so if it missed, it either crashed, or flew back up until running out of fuel and crashing, too.
- taneq 7y ago
  Mass distribution isn’t part of it as long as things are symmetrical (https://en.m.wikipedia.org/wiki/Pendulum_rocket_fallacy https://en.m.wikipedia.org/wiki/Pendulum_rocket_fallacy) but yeah, threading the needle like SpaceX does is not easy.
  - anovikov 7y ago
    Due to fuel slosh, things aren't symmetrical really.
  - TeMPOraL 7y ago
    Got to say, I don't understand how the argument in that article works. If Goddard's rocket that's on the photo had a canvas stretched between the wires/pipes that form its body (I assume it's a part of the rocket, and not a launch platform), then I'd expect aerodynamic forces to act on them, countering the tilt. Conversely, if such surfaces were above of the engine, I'd expect them to make the construction unstable.
    - taneq 7y ago
      You're right that any canvas stretched around the frame could act as aerodynamic stabilizer fins. The pendulum rocket fallacy is the assumption that a higher mounted engine will stabilize the rocket's direction due to it 'hanging' from the engine, by analogy with a pendulum (where the higher a point you 'hang it from' the more stable it is). The fallacy lies in the fact that the pendulum is hung from a fixed point which can apply forces to generate a stabilizing torque, whereas there are no such outside forces generated by the rocket engine (other than the thrust it produces). Fins totally work and that's why almost all rockets use them to some degree for stabilisation while in the atmosphere.
  - anovikov 7y ago
    But for landings, it's totally a part of it. If there is a mentionable lateral velocity component, rocket will tip over on landing unless it's center of gravity is very low. It happened just once with SpaceX rocket though.
protomikron 7y ago
Cool project, but ... that website gave my browser cancer (if you scroll down too far, your history is messed up and back button does not work).
choeger 7y ago
That is innovation right there in our faces. All that stuff was theoretically possible ten or twenty years ago. But completely impractical for a single hobbyist. Not to mention that propulsive rocket landing is a thing for -what? Six years?- in the real world now.
- steeve 7y ago
  It's crazy how some things can rapidly go from breakthrough to commodity nowadays. It reminds me of early drones vs ArduPilot in a way.
- madengr 7y ago
  More like 50+ years, if you count the LIM, and all other retro-rocket use.
- ballooney 7y ago
  There were hobbyists making thrust-vectored rockets at this scale twenty-ish years ago. e.g. http://michael.sdf-eu.org/Gyroc/ http://michael.sdf-eu.org/Gyroc/
  - perfectphase 7y ago
    Gyroc was amazing at the time and is still spoken about in hushed tones in the UK HPR community. While it was using ADXL50 devices for acceleration, the main gyro was an entirely custom built mechanical rotating gyro, wish I still had some pictures of it. Now that's all on a single chip you hardly even notice on the board :) Some pictures of it are here http://ukrocketman.com/rocketry/gimbal.shtml http://ukrocketman.com/rocketry/gimbal.shtml
- tigershark 7y ago
  The first falcon 9 landing was about 4 years ago if I remember correctly
lnsru 7y ago
In my eyes it’s amazing business using affordable hardware components. Respect for the creator! I dream finding similar niche.
illys 7y ago
Like SpaceX? "If you love rockets, you can’t help but notice that real space launch vehicles lift off the pad slowly, but model rockets zip up like darts." That reminds me of a common issue with modeling: when you divide sizes by N, you divide surfaces/light-reflexion/air-resistance/lift by NxN and volumes/weights by NxNxN. A 1/10th model is 1/1000th of the original weight with identical materials. All the dynamics are different and easier at smaller scales. This makes the real thing an expert work while modeling is reachable by hobbyists - very good ones in this case.
- tomxor 7y ago
  > All the dynamics are different and easier at smaller scales. Are you sure about this part? (not rhetoric). Non-linear scaling of surface and volume are simple to understand, but dynamics doesn't look so straight forward to me... in my short lived experience trying to fly very small model helicopters, it was clear that the smaller they are the more unstable they were. I wasn't sure how much of this was due to limitations in human reaction time and how much was inherent aerodynamic instability at smaller scales. In these rocket models the human limitation is clearly removed, the remaining dynamics look faster at least which may or may not run up against higher frequency sensor data and processing requirements... are there other dynamics i'm missing? i guess materials don't bend much at this scale?
  - TeMPOraL 7y ago
    Different? Yes. Easier? Depends. One thing you gain with size is intertia, which grows with N³, and depending on the design, can be helpful for stability.
    - tomxor 7y ago
      Yes, thanks, this is what I meant but the relationship was not clear to me before, it seems obvious in retrospect: n^3 * density = mass scales cubed, which as far as control is concerned is both good (lower impulse requirements), and bad (lower relative mass requires much finer control)... happy to be told how to express the later formally :)
andreareina 7y ago
Fun fact, the landing method described is called a "suicide burn"[1]. [1] https://space.stackexchange.com/questions/10307/what-is-a-suicide-burn#10308 https://space.stackexchange.com/questions/10307/what-is-a-su...
Robotbeat 7y ago
Joe Barnard, who looks a bit like the energy & space entrepreneur, earning him the title among his friends of “discount Elon Musk,” is one of the very best channels among tinkerer YouTube. Not annoying or fake enthusiasm like some of the other channels (but is enthusiastic!), innovative, informative, and fun-loving. A joy to watch his videos. Also, I had ice cream with him one time after watching an Antares launch in Virginia. Also good to see Make isn’t dead.
- jcims 7y ago
  Totally agree. Very prolific with a mix of software and hardware engineering, not at all shy about showing failures and setbacks and puts a lot of effort into the production value of his content. One of my favorites on YouTube for sure. I do hope he gets into hybrid or liquid propellant to avail himself of some basic thrust control...his new test stand has me hopeful. https://www.youtube.com/channel/UCILl8ozWuxnFYXIe2svjHhg https://www.youtube.com/channel/UCILl8ozWuxnFYXIe2svjHhg
  - Fiahil 7y ago
    > not at all shy about showing failures and setbacks This is the same reason why I like Alec Steele, a popular blacksmith channel! It's much more interesting to learn about all the mistakes, failures and bad assumptions than to see a perfect, finished product from end to end.
    - EvergreenTree 7y ago
      If you haven't found him already, you might like Wintergatan. Martin Molin of Wintergatan is currently in the process of designing and building a successor to a marble machine instrument he built a few years ago and is extensively documenting the process through YouTube. He doesn't shy away from showing mistakes either and all of his videos are beautifully shot and scored (often with music by him). If you are interested in engineering of any kind, I would highly recommend watching the Marble Machine X series from the start. He learns (and thus teaches) a lot of valuable lessons in the process and it is really satisfying to see it all finally coming together.
JoeAltmaier 7y ago
I showed my wife the video, and she remarked "You know, we went to the moon with less than that". So, puts it in context! So much possible now that was unthinkable back then.
stuff4ben 7y ago
We've gone from Elon Musk doing cutting edge stuff as a billionaire to a guy doing the same thing in his backyard within a decade. What an amazing time to be alive!
chasd00 7y ago
I highly suggest doing some digging into the rocketry hobby (especially high power rocketry). Or, as my wife would say, "go down the rabbit hole". It's like software development, there's some heavy duty stuff being done by incredibly skilled and talented people outside of work hours. For example, this guy put a rocket over 200k feet altitude on COTS motors https://mach5lowdown.com/2018/11/07/phx4-rocket-launch-to-200000ft/ https://mach5lowdown.com/2018/11/07/phx4-rocket-launch-to-20... Also, check out the engine this guy is building http://www.watzlavick.com/robert/rocket/regenChamber3/photos/index.html http://www.watzlavick.com/robert/rocket/regenChamber3/photos...
monocasa 7y ago
I thought vectorable thrust could run you afoul of ITAR, and pushed you into a much higher realm of scrutiny, since you've basically designed a missile.
- robotresearcher 7y ago
  In the article he declares he is doing stability control as opposed to guidance control, and only the latter is regulated.
  - monocasa 7y ago
    How do you land without doing guidance control?
    - fotbr 7y ago
      He's not landing it back at the pad or anything like that, just wherever it happens to be coming down at. Then keep it vertical(ish), keep it from moving too fast sideways or it'll tip over (again, stability, not guidance), and wherever it touches down, it touches down.
      - monocasa 7y ago
        So by design, the rocket motor is going to be active, and pointing at something he doesn't control?
deleted 7y ago
[deleted]
nategri 7y ago
After all the dire news in May I'm very happy so see good content on a Make domain :)
georgeecollins 7y ago
I have been launching rockets with my son the last few years, but it was kind of boring after a while because you I thought you can't (legally) introduce any controls. I thought! This has taught me that you can introduce controls for stability. That sounds pretty exciting.
davefp 7y ago
After seeing the headline I thought "If this is by anyone other than Joe Barnard they've really missed an opportunity here". Glad to see it's him! His videos are always in-depth and don't hand-wave or gloss over the various technical problems he encounters/fixes. He also does detailed breakdowns on the successes and failures of his launches which I really enjoy.

457 points by gscott 7y ago

stwr 7y ago

Been a big fan and supporter of Joe's work for a long time, really amazing work he is doing and how open he is about it, sharing lots of his knowledge in the BPS.space discord. Great to see him on the front page!

Sendotsh 7y ago
He’s such an inspiration. Zero background in any of this and just went “This looks cool, I’m going to figure it out”. His videos are incredibly entertaining and educational too.

gridspy 7y ago

If you want a quick video overview: "BPS.Space - Channel Trailer - 2019" https://www.youtube.com/watch?v=OE0_-g7YV1M https://www.youtube.com/watch?v=OE0_-g7YV1M

jiofih 7y ago

The Falcon Heavy model launch is one of the funniest and inspiring things I’ve seen: https://m.youtube.com/watch?v=ff5245EBfis https://m.youtube.com/watch?v=ff5245EBfis

JoeAltmaier 7y ago
Awesome you mean! Even when it doesn't work, it's doing something amazing. Somebody buy this guy a Red Button, he deserves it.

anovikov 7y ago

Trick of SpaceX success wasn't in vertically landing rockets - with mass being concentrated in the bottom in form of engines, thrust structure, and legs, it's not all that hard. What was extremely hard, is havigation and control to enable return back to launch site optimally, going through narrow corridors of acceptable parameters (go too shallow and you risk being unable to correct your position in the end as precision drops, go too steep and rocket breaks up due to aerodynamic forces, and so on), while burning minimum fuel. That was an insanely difficult GNC task which took so many iterations to perfect out... Plus yes, on landing they didn't have a second chance as rocket couldn't hover - minimum engine thrust was bigger than it's mass so if it missed, it either crashed, or flew back up until running out of fuel and crashing, too.

taneq 7y ago
Mass distribution isn’t part of it as long as things are symmetrical (https://en.m.wikipedia.org/wiki/Pendulum_rocket_fallacy https://en.m.wikipedia.org/wiki/Pendulum_rocket_fallacy) but yeah, threading the needle like SpaceX does is not easy.
- anovikov 7y ago
  Due to fuel slosh, things aren't symmetrical really.
- TeMPOraL 7y ago
  Got to say, I don't understand how the argument in that article works. If Goddard's rocket that's on the photo had a canvas stretched between the wires/pipes that form its body (I assume it's a part of the rocket, and not a launch platform), then I'd expect aerodynamic forces to act on them, countering the tilt. Conversely, if such surfaces were above of the engine, I'd expect them to make the construction unstable.
  - taneq 7y ago
    You're right that any canvas stretched around the frame could act as aerodynamic stabilizer fins. The pendulum rocket fallacy is the assumption that a higher mounted engine will stabilize the rocket's direction due to it 'hanging' from the engine, by analogy with a pendulum (where the higher a point you 'hang it from' the more stable it is). The fallacy lies in the fact that the pendulum is hung from a fixed point which can apply forces to generate a stabilizing torque, whereas there are no such outside forces generated by the rocket engine (other than the thrust it produces). Fins totally work and that's why almost all rockets use them to some degree for stabilisation while in the atmosphere.
- anovikov 7y ago
  But for landings, it's totally a part of it. If there is a mentionable lateral velocity component, rocket will tip over on landing unless it's center of gravity is very low. It happened just once with SpaceX rocket though.

protomikron 7y ago

Cool project, but ... that website gave my browser cancer (if you scroll down too far, your history is messed up and back button does not work).

choeger 7y ago

That is innovation right there in our faces. All that stuff was theoretically possible ten or twenty years ago. But completely impractical for a single hobbyist. Not to mention that propulsive rocket landing is a thing for -what? Six years?- in the real world now.

steeve 7y ago
It's crazy how some things can rapidly go from breakthrough to commodity nowadays. It reminds me of early drones vs ArduPilot in a way.
madengr 7y ago
More like 50+ years, if you count the LIM, and all other retro-rocket use.
ballooney 7y ago
There were hobbyists making thrust-vectored rockets at this scale twenty-ish years ago. e.g. http://michael.sdf-eu.org/Gyroc/ http://michael.sdf-eu.org/Gyroc/
- perfectphase 7y ago
  Gyroc was amazing at the time and is still spoken about in hushed tones in the UK HPR community. While it was using ADXL50 devices for acceleration, the main gyro was an entirely custom built mechanical rotating gyro, wish I still had some pictures of it. Now that's all on a single chip you hardly even notice on the board :) Some pictures of it are here http://ukrocketman.com/rocketry/gimbal.shtml http://ukrocketman.com/rocketry/gimbal.shtml
tigershark 7y ago
The first falcon 9 landing was about 4 years ago if I remember correctly

lnsru 7y ago

In my eyes it’s amazing business using affordable hardware components. Respect for the creator! I dream finding similar niche.

illys 7y ago

Like SpaceX? "If you love rockets, you can’t help but notice that real space launch vehicles lift off the pad slowly, but model rockets zip up like darts." That reminds me of a common issue with modeling: when you divide sizes by N, you divide surfaces/light-reflexion/air-resistance/lift by NxN and volumes/weights by NxNxN. A 1/10th model is 1/1000th of the original weight with identical materials. All the dynamics are different and easier at smaller scales. This makes the real thing an expert work while modeling is reachable by hobbyists - very good ones in this case.

tomxor 7y ago
> All the dynamics are different and easier at smaller scales. Are you sure about this part? (not rhetoric). Non-linear scaling of surface and volume are simple to understand, but dynamics doesn't look so straight forward to me... in my short lived experience trying to fly very small model helicopters, it was clear that the smaller they are the more unstable they were. I wasn't sure how much of this was due to limitations in human reaction time and how much was inherent aerodynamic instability at smaller scales. In these rocket models the human limitation is clearly removed, the remaining dynamics look faster at least which may or may not run up against higher frequency sensor data and processing requirements... are there other dynamics i'm missing? i guess materials don't bend much at this scale?
- TeMPOraL 7y ago
  Different? Yes. Easier? Depends. One thing you gain with size is intertia, which grows with N³, and depending on the design, can be helpful for stability.
  - tomxor 7y ago
    Yes, thanks, this is what I meant but the relationship was not clear to me before, it seems obvious in retrospect: n^3 * density = mass scales cubed, which as far as control is concerned is both good (lower impulse requirements), and bad (lower relative mass requires much finer control)... happy to be told how to express the later formally :)

andreareina 7y ago

Fun fact, the landing method described is called a "suicide burn"[1]. [1] https://space.stackexchange.com/questions/10307/what-is-a-suicide-burn#10308 https://space.stackexchange.com/questions/10307/what-is-a-su...

Robotbeat 7y ago

Joe Barnard, who looks a bit like the energy & space entrepreneur, earning him the title among his friends of “discount Elon Musk,” is one of the very best channels among tinkerer YouTube. Not annoying or fake enthusiasm like some of the other channels (but is enthusiastic!), innovative, informative, and fun-loving. A joy to watch his videos. Also, I had ice cream with him one time after watching an Antares launch in Virginia. Also good to see Make isn’t dead.

jcims 7y ago
Totally agree. Very prolific with a mix of software and hardware engineering, not at all shy about showing failures and setbacks and puts a lot of effort into the production value of his content. One of my favorites on YouTube for sure. I do hope he gets into hybrid or liquid propellant to avail himself of some basic thrust control...his new test stand has me hopeful. https://www.youtube.com/channel/UCILl8ozWuxnFYXIe2svjHhg https://www.youtube.com/channel/UCILl8ozWuxnFYXIe2svjHhg
- Fiahil 7y ago
  > not at all shy about showing failures and setbacks This is the same reason why I like Alec Steele, a popular blacksmith channel! It's much more interesting to learn about all the mistakes, failures and bad assumptions than to see a perfect, finished product from end to end.
  - EvergreenTree 7y ago
    If you haven't found him already, you might like Wintergatan. Martin Molin of Wintergatan is currently in the process of designing and building a successor to a marble machine instrument he built a few years ago and is extensively documenting the process through YouTube. He doesn't shy away from showing mistakes either and all of his videos are beautifully shot and scored (often with music by him). If you are interested in engineering of any kind, I would highly recommend watching the Marble Machine X series from the start. He learns (and thus teaches) a lot of valuable lessons in the process and it is really satisfying to see it all finally coming together.

JoeAltmaier 7y ago

I showed my wife the video, and she remarked "You know, we went to the moon with less than that". So, puts it in context! So much possible now that was unthinkable back then.

stuff4ben 7y ago

We've gone from Elon Musk doing cutting edge stuff as a billionaire to a guy doing the same thing in his backyard within a decade. What an amazing time to be alive!

chasd00 7y ago

I highly suggest doing some digging into the rocketry hobby (especially high power rocketry). Or, as my wife would say, "go down the rabbit hole". It's like software development, there's some heavy duty stuff being done by incredibly skilled and talented people outside of work hours. For example, this guy put a rocket over 200k feet altitude on COTS motors https://mach5lowdown.com/2018/11/07/phx4-rocket-launch-to-200000ft/ https://mach5lowdown.com/2018/11/07/phx4-rocket-launch-to-20... Also, check out the engine this guy is building http://www.watzlavick.com/robert/rocket/regenChamber3/photos/index.html http://www.watzlavick.com/robert/rocket/regenChamber3/photos...

monocasa 7y ago

I thought vectorable thrust could run you afoul of ITAR, and pushed you into a much higher realm of scrutiny, since you've basically designed a missile.

robotresearcher 7y ago
In the article he declares he is doing stability control as opposed to guidance control, and only the latter is regulated.
- monocasa 7y ago
  How do you land without doing guidance control?
  - fotbr 7y ago
    He's not landing it back at the pad or anything like that, just wherever it happens to be coming down at. Then keep it vertical(ish), keep it from moving too fast sideways or it'll tip over (again, stability, not guidance), and wherever it touches down, it touches down.
    - monocasa 7y ago
      So by design, the rocket motor is going to be active, and pointing at something he doesn't control?

deleted 7y ago

[deleted]

nategri 7y ago

After all the dire news in May I'm very happy so see good content on a Make domain :)

georgeecollins 7y ago

I have been launching rockets with my son the last few years, but it was kind of boring after a while because you I thought you can't (legally) introduce any controls. I thought! This has taught me that you can introduce controls for stability. That sounds pretty exciting.

davefp 7y ago

After seeing the headline I thought "If this is by anyone other than Joe Barnard they've really missed an opportunity here". Glad to see it's him! His videos are always in-depth and don't hand-wave or gloss over the various technical problems he encounters/fixes. He also does detailed breakdowns on the successes and failures of his launches which I really enjoy.