Test Launch: https://www.youtube.com/watch?v=QQt-9SSJ51c
Test Landing: https://www.youtube.com/watch?v=lXy-x6lkQvQ
This appears to be working with solid rocket motors, thrust vectoring, and a carefully timed ignition. How do they get accurate distance to ground? Is altitude just a constant for these tests?
I wonder what scale you would need to get the rocket into space/orbit? SpaceX should fund this guy to find out, could prove to be a valuable bootcamp for real SpaceX employees in the future?
There's a great "what if" xkcd about using solid fuel model rocket engines (the same type used in BPS.space's rockets) to get to space and orbit.
The summary is that you may be able to use a stupendously large number of them to get to space, but orbit is physically impossible. You'll need a different propulsion method.
The smallest rocket that has ever carried a payload to orbit is the SS-520. It's ~30 feet tall, ~2 feet in diameter and weighs ~5,700 pounds. It set the record in February 2018, so it's a pretty recent record.
(1) Flight control and guidance systems (including guidance sets) specially designed for articles enumerated in paragraph
(a) of this category (MT for those articles enumerated in paragraphs (a)(1) and (a)(2) of this category);
Note to paragraph (h)(1): A guidance set integrates the process of measuring and computing a vehicle's position and
velocity (i.e., navigation) with that of computing and sending commands to the vehicle's flight control systems
to correct the trajectory.
Hobby rockets use simple solid fuel engines you’ll need to build an actual liquid rocket engine with controlled thrust that can be reignited the rocket it self also need to be large enough to be aerodynamically controlled and hobby rockets tend to be too light so they’ll simply tumble in the wind.
While you don’t need to build something the size of a falcon 9 for propulsive landing you’ll need something way larger than any hobbiest rocket I know of for sure.
If you just want the control part then simulating it is likely going to be a better use of your time, you can even build your own auto-pilot for something like Kerbal Space Program it won’t be the real thing but it would at least be achievable.
Hybrid engines which use solid fuel and a liquid/gaseous oxidizer can be controlled better but these are often very hard to reignite.
So this means you'll have to have additional engines that are used just for the slam landing, technically possible but again might be harder to construct than a liquid engine since solid fuel engine ignition is also fairly inconsistent.
The Soyuz capsule uses rockets to soften the landing but these technically aren't propulsive landing and the landing forces tend to vary quite a bit between landings.
Overall when I think about this problem as a hobby the software isn't going to be the biggest blocker here especially considering the speeds/altitudes that we are talking about as well as the overall mass of the rocket, in fact since these rockets are going to be considerably smaller and would travel considerably slower you could absorb much more of their relative energy via hydraulics so the amount of precision needed for the slam/hover landing isn't as great.
You might be able to do it with a hybrid rocket engine where the oxidizer is liquid or gaseous but the fuel is solid but I'm not sure.
As for the weight if you make it small but heavy then you are likely to lose aerodynamic control since it essentially will be a free falling brick.
You need something that is massive enough to resist the wind but have a large enough surface area to be aerodynamically stable and controllable, I'm not saying it's not possible I'm just saying that the time and money that you'll have to invest in it is going to be quite likely astronomical and while I don't doubt that there might be individuals that might be able to do it on their own this likely would require a pretty large team of dedicated people to solve.
If you are capable of building a rocket engine I would actually focus on simply building a hovering rocket rather than trying to land it, or at least you better off trying to build a hobbyist grasshopper https://en.wikipedia.org/wiki/Grasshopper_(rocket) than a Falcon 9.
But realistically even for something like this you should be better prepared to spend the better part of a decade building it and likely at least a few $100K's in funding since none of this is going to be cheap to produce.
If you go this route you might as well just use an EDF engine instead of a rocket engine for the landing.
Scale matters. Bigger things are more stable.
The same effect makes walking robots harder at small scale, unless they cheat by having large feet and stiff ankles.
If you can react 2x as fast the control problem is easy. If you can react 1x as fast, the control problem is feasible but requires accurate tuning.
For average-height humans on earth, the height of the center of mass is about 1.3m, so sqrt(l/g) is about 350 mS. Human response time, from the inner ear to the ankle muscles is about half of that. That gives some intuition for how hard it is to balance with 2x faster response. Balancing a yardstick on your finger is closer to 1x faster response.
This could theoretically be used to land vertically, though that hasn’t been achieved.
As others have been commenting, it's a completely different ballgame if you want to use propulsion engines and still be able to land it. At that point, you're just building a smaller version of the real SpaceX rockets, and that sounds much more difficult (not to discourage anyone from trying!).
No, but that is what people will tell you about every idea from Facebook to a pet rock.
If you want to do it, good luck. It will not be easy.
If you want a simple project- Add your arduino, get GPS, accelerometer and a noise maker. (Edit: if you are really ambitious, get it to communicate live)
See if you can optimize anything. I would guess your goal is to play in embedded C++ anyway.
The software is written by one guy in his freetime. Pretty amazing feat, considering how difficult it is, and that he has no way of testing it before the actual launch. It worked flawlessly the first time.
Here's a video of the Nexø 1 launch that uses the system to control the rocket on its ascent.
This video shows some technical data streamed live from the rocket that gives a good overview of what the jetvanes are doing. Notice the graphic in the lower left corner; The H in the middle is the floating launch platform (12x14 meters) and the moving red dot is the position of the rocket in the X-Y plane. On the whole trip it never moves more than a few meters from the center. Really impressive stuff...
I know it's not exactly what you're asking, but it's close, so I thought it might have some value.
But for all the model rockets I've seen, their mass ratios are quite small, and their motors don't allow for throttling. They blow their load as fast as they can and then drift down.
Software is not the biggest problem, you need a hobby quality throttling and gimbaling rocket motor, and I'm not sure if they even exist.
One of my hobbies is baking bread. I've seen professional bakers bake 100% whole wheat loaves with an open crumb. It's semi-magic and not practical. They literally spend years failing at it, learning every variable, sourcing different artisanal flours and setting up a professional workspace.
I do try it sometimes, and I always fail. It's interesting, but...
Sometimes I actually want to eat some nice bread. There are times when I say, just do a 33% whole wheat loaf Erik, it's fine. It is practical and it's still fun and it's a nice day doing my hobby. There's still plenty of sport in it and plenty to learn.
I don't think there's any open-source software for this, but the software isn't really the problem anyways. It's more about getting sensors that are accurate enough and actuators for thrust direction and power that are accurate and fast enough. I don't think there's anything off the shelf for this, and building and testing it, at that scale, is possible, but not cheap or easy. Once you get all of that together, the software is a relatively small and simple problem, and probably too specific to your exact setup for it to make sense to open-source.
Probably the biggest problem is that model rockets use solid-fuel engines, which cannot be controlled once ignited and probably don't have the greatest consistency in thrust and time. Short version is you ain't gonna do a propulsive landing with that. You'd have to build your own micro-scale liquid-fuel rocket engine. I don't know that much about building rocket engines, but it sure looks like building ones on the scale to take commercially viable weights into orbit is very hard. I'm going to bet that building one on a micro scale would be substantially harder and probably require the services of several experts in the field.
If you're interested in the area, see what info you can find about military missiles, like for MANPADS, guided anti-armor missiles, and some of the lighter AAMs. Every one I've heard of uses solid-fuel engines too, but they do have good control systems for guidance. I don't think any of them care much about the exact thrust levels, just get it going good and fast and the active guidance systems can handle the rest. But you're gonna need that precise thrust control if you want to land propulsively. Relatedly, if you tried to actually build your landable model rocket, I would expect the appropriate Government agency in your jurisdiction to take a very keen interest in exactly what you plan to do with these things. It may involve spending lots of time and money to convince them that you definitely won't give any of your stuff to whatever the relevant agency considers to be a terrorist group or rouge state.
A team of engineering graduate students with a bit of funding might succeed, but the cost and custom hardware would be pretty high. The problem also gets more difficult as the rocket gets smaller.
Also, failed rockets are flying bombs, not something to be done lightly.
You can see what spacex (probably) does to turn it into a tractable problem for real time control in http://www.larsblackmore.com/iee_tcst13.pdf (Blackmore leads entry, descent, and landing at spacex).
And the design of the control system for a small model rocket and whatever control authority can be created for it in hardware are super hard compared to however it is implemented.
There's no "practical" reason to make it land vertically. Model rockets can land safely using parachutes.
I don't know whether he got shut down by the authorities or not.
> “Missiles”. (All) Rocket systems (including ballistic missiles, space launch vehicles, and sounding rockets) and unmanned aerial vehicle systems (including cruise missiles, target drones, and reconnaissance drones) “capable of” delivering at least 500 kilograms payload to a range of at least 300 kilometers.
Not as broad as I would have thought. You could do a lot of damage with 499 kg of TNT, and nuclear bombs weigh less. Little Boy was 64 kg of uranium according to .
A gun-type bomb doesn't require a very complex system to set it off. The complicated bomb was Fat Man, an implosion bomb, that required very precisely calculated explosive lenses and precise timing circuits.
Or the W54 was reputedly much lighter, but with a larger diameter.
which is the story of a German rocket club which first got shut down by the Nazis because "somebody could get hurt" and then the Nazis thought it over...
Probably your best bet is a hypergolic monopropellant such as hydrogen peroxide.
For example (see J. Clark, Ignition!) nitric acid is hypergolic with turpentine, but not hypergolic with kerosene.
But from previous research it sounds really simple to concentrate (up to 70%) if you can acquire enough low concentration hydrogen peroxide. So much so that it kinda scares me that I have a bottle of 3% hydrogen peroxide in my house.
Edit: Again, this is a bad idea, but here's the title of my source: Methods for Concentration of Hydrogen Peroxide To Obtain It in Anhydrous Form
A bottle that large of TATP could blow up a plane but you'd be lucky to make it to the airport with it before it explodes.
The 90%+ stuff used in rocketry is hard to get because it is dangerous to handle.