mardlamock

Just do a 4 DoF simulation of the rocket launch with orbital mechanics and drag taken into account, subdivide gravity turn into say 100 steps and use a solver to get an estimate. Its not all that hard. When doing the actual numerical simulation you will have to split the diff equation as many times as needed in order to be able to even do it. Pop an excel sheet to do it first and it shouldnt take you longer than a couple of hours.

Nakka is the place to go

How accurately can a spacecraft hold its attitude? Wouldnt that also affect the range of a laser weapon due to the aiming being off? Lets assume the maximum error in aim is of around 4 meters. Current space telescopes can hold an attitude with 0.007 arsecs of accuracy, that gives us that the maximum engagement distance is of 83000 kilometers. Lets also say that the approach speed is of 6 kilometers per second, which is sort of reasonable considering the distance between colonies and the orbital mechanics associated (say a moon colony vs GEO colony). That gives us an engagement time of almost 4 hours, that doesnt seem too long actually. What do you guys think?

What makes you think that? An old Atlas with modified engines could take a considerable payload into orbit. Besides, only having to use the same set of engines reduces costs a lot, if you look at the numbers, the motors take a really significant chunk of the total launch cost. The dry mass to payload ratio is also significantly lower for SSTO's than for regular multi stage vehicles, that means that for each kg of payload you need less rocket. - - - Updated - - - Yup, thats what I am talking about.

Staging events are the most critical event in any rocket launch. Read this http://exoscientist.blogspot.com.ar/2013/11/the-coming-sstos-falcon-9-v11-first.html

I for one agree with most of what you said. I think they should dump their current 2 stage model and go for a vertical takeoff SSTO using a modified falcon 9's first stage, the lowered complexity thanks to no staging events and only using one set of engines would lead to a significant decrease in prices. Maybe the could get reusability in that SSTO too, idk though.

You are forgetting about the tyranny of the rocket equation people, the delta v used to compensate for gravity losses equates to a lot of propellant and a much larger vehicle overall.

Use nose blown recovery.

Hi everyone! So, I ve been thinking about how high a plane can climb given an initial airspeed and a minimum airspeed. I first thought it was a simple matter of potential+kinetic energy remaining equal throughout the flight, but then I brain farted and now I dont really know what to think. If the only forces acting on the aircraft were gravity and drag, then the final mechanical energy would be always less than the initial, but that is never true because we also have lift. When you add lift into the equations, the rate at which you lose energy diminishes considerably, if you are ascending at a constant rate that is. This is because the vertical lift force cancels the weight of the aircraft, and the resulting energy losses are only due to drag and the horizontal lift force component. Example: a plane is going at 200m/s, it performs a climb until it reaches 180m/s at a constant ascent rate of 5m/s. Without lift or drag the maximum height the plane coud reach would be 20m (1/2*20^2=g*h). Assuming that the angle with respect to the surface of the earth is small then the horizontal lift force component is negligible. In order for the final energy to be less than the initial energy, the acceleration due to drag has to be more than 5 m/s^2. But what if it isnt? Lets say instead of it being 5m/s^2 its 4m/s^2, then, the plane will take 5 seconds to lose the 20m/s we were willing to convert into height. And as we said before, the climb rate remained constant at 5m/s, which means that the height will increase by of 25m. The thing is that, if it increased to 25 m then the system has more mechanical energy than at the start of the climb. So, what am i missing here? I have seriously got no idea where the extra energy comes from and wether its actually available for use. Anyways, thanks for reading so far! Please reply and tell me what you think!

You guys need some Subjective theory of value here. http://en.wikipedia.org/wiki/Subjective_theory_of_value.

I think there is potential for a next spacex, but it would have to be in India or some cheap ass place. Massively manufactured modular rockets, with cheap indian labour. Thats how electronics became so cheap people. OUTSOURCING!!!

I would like to be Cryopreserved and launched into space, that way I can avoid natural disasters whilst still having the small chance of being revived.

Gold is not really used for speculation by people who know its value, its valuable because it is useful for the industries, does not depend on a central bank for its creation and is a great way of storing value, it lasts thousands of years without losing its properties. Gold is the underdog of investments in the modern world, people would much rather fool around with stocks and cheap central bank money than actually mine gold.

Gold prices kept high artificially? If anything they are being kept low due to speculation, there is an overall fear of gold, every major investment and banking firm is pulling the price down with bearish long term views. We'll see what they say in the next recession.

That price must be way off, that is 1/3 of the price of gold per kg. Demand would also rise with lower prices, demand for computers rose when they became more affordable, same with pretty much any other useful product. I think gold is a safer bet for mining, and I believe its a lot more common in asteroids.

With current technology and prices its impossible, in the future with cheaper launch vehicles it may become a reality. Im just saying its not as far fetched as you think. Return on investment would not be that high though, probably around 10%. I'll leave it to DSI and Planetary Resources to find out

Im afraid your numbers are wrong, a metric ton of scandium is $270 millon. And if you are the only supplier, then flooding the market isnt an issue, you will never sell it below your operational costs+what you are willing to compromise.

Its not easy, but it can still be profitable. Even with the current prices, it only costs around 33K/kg to return cargo from orbit, the current price of gold is at 38k, of course you have to mine it and stuff, but you only need to launch once. If we assume that within the next decade or so the price per kg to launch into orbit gets cut in half, we re looking at a very profitable business (but you'd need a decent chunk of capital to get even remotely started). The price of gold could also go up a lot, as some people are predicting, which would also help boost the profitability. The most important part about the whole process is getting space ore processing and manufacturing working, there are many challenges to be overcome but its not unreasonable to think that within the next few decades it can be solved. Even current gold mining operations are unprofitable for the first couple of years, and they also require millons of dollars to set up.

I think that we should all remember that what is profitable or valuable is just what people want, we dont need computers to survive, we dont need KSP to stay alive, yet we still have these things, even though they are pointless in it of themselves. Space is no different, what matters most is getting regular people to support the space industry, billons of dolars are donated every year to human rights organizations, charity funds, and churches,etc. space exploration could be no different. For that matter, I strongly believe a Moon mission is better, it gets people interested in space and shows them what we can do with current technology. We should not work towards getting NASA a bigger fund through taxes, instead, we should get people to voluntarily fund space exploration, just as they do with hundreds of other things. Of course that working within current demand for goods is important, the growth must not depend now on national space programs, it must be founded on solid economic ground; but getting the average joe to voluntarily give 100$ for space exploration is also extremely important.

Cool, I ve only built up to J-K class, but completly on my own. I cant really test anything larger here. Electrical ignition is a must for the first stage, that would be tricky, but not impossible. APCP would make this waay more feasible, 3 stages or even less. Im sure most of you have already seen this rocket, but OP's would have to be like 4 of them stacked up ontop of each other. (its ridiculous, i know)

Of course there would be path deviations, but I dont really think they would be as large as you say. The trickiest ignition would be the first one, the rest would be so hard as you could just expose the pyrogen of the next stage as the earlier finishes its burn. The motors I am talking about last 1.5ish seconds each, so the total burn time wouldnt be all that long. OP doesnt have the building skills IMO to build such a motor, but someone experienced might. May I ask, what class were the motors you built in?

I know, but I did the math and it does work. gives about 1600m/s of dv, launching from a balloon thats more than enough. With 5 stages you get 2000m/s of delta V, so you could do with a camera. - - - Updated - - - That depends alot on the rocket itself and its initial acceleration, the first stage should have a good TWR and it should be spin stabilized (Like most rockets this size). It would be like 2,5 meters tall and could probably have diameter as small as (or 5 if you really want to minimize drag losses).

It would have to be a motor with fins, I can build a pretty decent motor with 900m/s of delta v, wet mass 1.5kg, dry mass 0.5kg, so I guess you could do with that. 4 stages would just about give you enough delta v to make it into space.

You dont seem to know much about building engines and stuff, someone with experience might just be able to make into space, but you have more chances of losing your fingers due to CATO.

I was thinking about making a t-shirt that showed and arm but instead of it having blood carrying veins and arteries, had UDMH and N2O4. It would read ''100% hypergolic veins''