christheman200

Just put a lens from a harddrive or CD reader in front of the camera.

Just quick update to say that everything is going well. The school year has started up, and I should have 2 or 3 classes to work on this project for the rest of the year. We have a 3D printer, which I am going to be setting up over the next week. I now have an 8 foot 4 inch tall water rocket in my house. I'm developing the recovery system for a general unguided flight test, which is quite close to being done. It will be based off of Arduino/Freeduino boards, and since I only have an Uno at the moment I may have to wait for my Pro Mini Freeduinos to come in before I launch. Losing a 40 dollar Arduino isn't my idea of fun, even though the whole rocket has cost much more than that so far. The head of our First Robotics team is working on a table which will balance a ball by shifting the table upon which it sits, and this happens to be pretty similar to my gimballing engine. Hopefully her work can help me out with my project. California was awesome! I passed by SpaceX, Tesla Motors, Space Shuttle Endeavour, the Orion Capsule, got past the front gates of JPL, and toured Caltech. For those of you who know him, I met Veritasium after my campus tour. There were also numerous giant telescopes.

Slosh may be a large issue, but I feel that it is unlikely to cause much grief. Your post made me realize that the air may leak out if g forces start going upwards. Under a parachute this should not happen. I haven't seen that gimballed rocket before. It looks very interesting! I might just steal some of that code.

Getting back to this thread. The project is far from dead! I'll be travelling from LA through San Francisco starting Thursday for a week or so. If any of you can manage to get me a tour of Caltech, JPL, SpaceX, etc., send me a message. That would be a really big deal for me! I only have about a 50 percent chance of getting tours of the above at the moment. As such, there won't be much construction and testing going on for a while. To make good use of this time I've created 6 pressure vessels, which will have cured by the time I get back. What's happened in the time since my last post? I have pressure tested a tank to 100psi through launching a water rocket, and even after many massive impacts the bottle held strong. I haven't created a coupler to chain together multiple tanks yet. I've also assembled 6 more tanks, which will cure while I'm in California. Recently I created a gimballing nozzle from Styrofoam, albeit without a nozzle, yet. I am going to figure out how to easily make a flexible nozzle over the next week. Last night I hooked up a servo to my arduino, and I hope to control it with a wii nunchuck, acting as a crude gyroscope, which will be taken from accelerometer data. Here's a video of the last launch of the day: The plan is as follows while on vacation: Figure out how to get the nozzle to gimbal Find an easy method of connecting pressure tanks Learn some control logic I have no knowledge of control logic, so this is where I will need to spend some time learning in the future. If you have a favourite tutorial on control logic, feel free to reply with a link.

I think you guys might have had a chance of performing some real science in space if you had stopped changing your objectives and goals as you went along. Flying by Mars as a first space mission for any agency is absolutely ridiculous.

I'd like to see you propose crashing into Phobos to the IAU.

Webster is beyond top of the line... and very expensive, definitely not what you guys need. SurplusShed is ok, but you can buy an 8 inch dob with mirror for $400, or less. Much more value there.

Tons of them. I suggest you join cloudynights. They can give you an outline of the different mirror makers. I'm not going to give any specifics because they all grind to different levels of precision.

Hey, go and post this on cloudynights.com We are the largest astronomy forum on the internet, and you'll get a lot more (helpful) help. I've built a lot of equipment, and I would suggest buying your own equipment at first. If you don't have experience with similar projects, it will take you a good number of months.

I've now modelled a gimballing nozzle, to be 3D printed in ~1 month. By fiddling with an online simulator, I have found that my craft will have around 60-75 m/s of delta-v. I'm debugging my own simulator at the moment. As well, my website is very much a work in progress.

There might be a few too many variables with a moving centre of mass to get a properly stabilized craft. As well, most of the weight belongs to the water held in the bottles, so there wouldn't be much mass, making the craft even more vulnerable to effects from the hose. If you have some free time today (a couple of minutes), would you mind finding a lightweight valve that you think would work with your method? I've been a bit stumped in what to use. What type of fitting should I use to let the nozzle gimbal? I've also put out a request for a graphic logo over in the space lounge: http://forum.kerbalspaceprogram.com/threads/86074-In-Need-of-Some-Graphics If someone wouldn't mind making a logo for the project, we'd be looking much more professional!

I just spotted this thread, and I've got to say that it seems genius. What I love about KSP is that its community is filled with people who dare to try the "impossible". I'm currently working on an automated landing water rocket on a thread in the science labs here http://forum.kerbalspaceprogram.com/threads/84593-Curiosity-Style-Egg-Drop-Lander/page9 From what I learn in this project, I might be able to give you guys some actual help. Keep going with this project. I vote for a Phobos flyby, because if we can even manage to pull off a cubesat launch, I think we can use our collective minds to do whatever we want.

I've been hard at work on a real, automated landing water rocket over on the science labs forum http://forum.kerbalspaceprogram.com/threads/84593-Curiosity-Style-Egg-Drop-Lander/page9 Having very little experience in graphics, I'm in need of someone who wouldn't mind whipping up a small logo for me. I'm imagining (and have sketched) something resembling a bottle rocket, with lander legs, touching down on the bottom of the circle which is the perimeter of the logo. It would be nice to have the words "Lansdale Engineering" around the outside. If you know anyone that could make this for me, it would be greatly appreciated if you pointed them my way. Thanks for reading through!

FCI, it is not feasible to run the craft off of an external source. The lines leading into the craft would destabilize it. I have already constructed two large water chambers, with two more on the way.

I have started an official twitter account! You can follow me at @LansdaleEng, or via https://twitter.com/LansdaleEng I will be posting daily updates on the lander, as well as engineering related subjects. At the moment, my father and I are working to put up a custom domain, and set up a blog sorts. Plans for today include working on a simulator, and making some graphics.

The lander may not be as unstable as you think at low velocities. The drag should still push in the same direction, and once it reaches a velocity of zero there will be a drag force of zero. I like the simplicity of a dumb landing system, but that's not what I'm looking to get out of this project. The official DragonEgg lander blog will be put up very soon. The idea of a kickstarter campaign to raise funds for this project is creeping into my mind.

K^2, I've witnessed the extreme accuracy of stepper motors in the past. They seem like a better option. If the rocket is designed to be aerodynamically stable, it should be statistically more stable, because any variation in the thrust of each engine in a 4 thruster system would make the rocket unstable, whereas in a single engine scenario, there is an overall smaller chance of this being as significant. Cantab, I would like to use your umbilical hose approach, but it would make the craft unstable from any interaction of the mass of the hose with the lander. I'm continuing research regarding the performance of the rocket.

The new idea is to use a SpaceX Grasshopper style rocket, which is much easier to construct, and can be used for a number of purposes. Hobby servos can slew around 60 degrees in 0.24 seconds. The fastest can do that in 0.04 seconds. I don't have much experience working with servos, however, so I suppose their may be a considerable time delay until rotation. Other than time delay, I don't see the servo speed being much of an issue, if fast servos are used. A stable rocket would ideally need very little corrective control as well.

I've gone ahead and spliced together a few pop bottles, which should be sealed in one week. Now I'm trying to set my mind on creating a gimballing nozzle. I've found what seems to be an almost perfect design here: I've sent the designer a message, and asked what he used to give the nozzle its degrees of freedom, perhaps a ball joint or piece of tubing. That's where I'm stuck at the moment. Another conundrum I have regards the use of solenoid valves and exhaust velocity. If I throttle the flow with a solenoid valve by pulsing the flow on and off, the pressure in the nozzle should be less than it is inside the tank. And if the exhaust pressure is lower, the exhaust velocity must be lower, and there will be a considerable delta-v loss. Is my reasoning valid?

Creature, your idea is very logical but I'm certain it won't work. Once any air pressure is released into the water tank, that pressure will stay in the tank until it can leave, and if your rocket is pointing down that is when all of the water has exited. I'm trying to comprehend the arrangement of the nozzle, valve, and gimbal point at the moment. It seems that if the throttle is before the gimbal point, the standard size of the nozzle after it would reduce pressure as the thrust is decreased, lending to a lower performance. It seems like a tough challenge to control the added mass of a solenoid valve after the gimbal.

^Yes, a common misconception with water rockets is that they are more efficient with convergent-divergent nozzles. I've managed to push a pop bottle to a pressure of 120 psi before, albeit I reinforced the bottle with plastic around the outside. However in retrospect it was a very bad method of reinforcement, and I expect that the bottle used could have withstood the pressure. If you want to hold 120 psi with a small metal tank, it can be incredibly thin. The problem with this is that it is very hard to form the metal this thin. Realistically, it is possible to make your pressure tank as thick as the plastic in a pop bottle, which will make it too heavy. One of the most important things about making metal tanks is that they are much, much more dangerous than plastic bottles. If the tank explodes, you'll have deadly shrapnel going everywhere, and cut metal is very sharp. Yes, chutes are crucial. I'm on our school's FRC team. I can't wait for school to start up again.

I've been playing around with a reputable on-line water rocket simulator, and my numbers aren't adding up to those of typical low power water rockets. I've now come to realize that I have been overestimating the weight of the craft by a factor of ~2. I have found that it may be considerably easier to construct a SpaceX Grasshopper style lander, using a single gimbaling engine with a throttle. For now I will assume that the engine is somehow gimbaled via servos. A conventional pop bottle weighs 49 grams, and with a 5 water bottle system, including a 50 gram egg, 3 50 gram servos and a 100 gram solenoid valve, the weight will tally to ~550 grams. At 120 psi, according to the following simulator, such a rocket will produce a delta-v of >28.6m/s. The simulator: http://polyplex.org/rockets/simulation/simulate.cgi This project is looking much more feasible now.

It seems that you did notice my comment regarding the egg coming down at >5m/s. Your servo motor option could work if it had a fast enough response time.

Well, landing the egg in a similar manner to that of the Yutu lander demands just as much technologically as it does to land on rocket power. As well, the parachute will only slow the craft to a speed of some odd 5m/s. If the craft has a TWR<1, the egg will come down at >5m/s. That is far too fast. If you are talking about using gyroscopes as in KSP, those don't really work very well in real applications.

OK, I'll keep the egg! Since the pressure varies over time, I'm going to need to recalculate my tolerances for landing. I've researched the construction of a thrust test stand, and I've come up with a solution. Two good resources among others are: http://www.instructables.com/id/Arduino-Load-Cell-Scale/ http://www.nerdkits.com/videos/weighscale/ - this company also sells the sensors for ~$10 in-case you don't want to take apart a scale In short, the load cell inside of a bathroom scale is hooked up to a signal amplifier, which is read by an arduino and logged to a computer. Finer details will come in the morning when I'm actually awake.