Hi Dominux,
A ground-to-orbit vehicle is, indeed, going to have to have a large mass (read rocket equation), especially since small rockets are more greatly penalized by air resistance. That's why some teams are going for rockoons, as you mentioned (they were used for very cheap sub-orbital flights back in the 50s, with payloads of a few kg). Once you bypass the atmosphere in this way, scaling laws are a lot more favourable, and you really don't want to have to lift more than necessary - a lighter satellite saves you fuel.
I'm not sure what you mean about a little payload having to fling stuff or have energy imparted - the little payload is the satellite, not the launch system. You can use as much mass as you want in the launch system - the nanosat just has to stay in orbit, for which it doesn't need to do anything by way of propulsion.
Best,
Paul
Hi all,
Wow - this thread has grown fast. A few quick answers to some points raised:
1) Why? What use is it? - For fun, and none at all, in that order. Also to prove that the world isn't run by accountants and safety officers.
2) 20 grams is too light. - No it isn't. We're beyond valves. 20 grams is plenty for a half-watt transmitter, a few square cm of solar panels, and more. Most entrants are looking to put video on their satellite (you can get camera modules weighing less than a gram). Some entrants are going for optical signalling. Either way, it's not really a problem.
3) "Other" applications/ICBMs etc - So, what? We're supposed to say 'nobody is allowed in space because there are terrorists who could use this technology'? If so, they've already won, haven't they?
4) Space junk - Yes, we'll be adding one or two pieces to the tens of thousands already up there. However, N-Prize entrants are mostly aiming for low (sub-200km) orbits, which will decay quite quickly.
5) Feasibility at the price - it's on the borderline of possiblity, using either single-use launchers OR using a small recoverable launcher (in which case, you can spend what you like on the launcher, and only the fuel and refurb costs count).
6) Cost of permits etc - If you want to get permits etc, then that's fine. Their cost is not counted as part of the budget (see full rules).
7) Come on, guys, loosen up a little! This is an invitation to play, and to try something almost impossible for no practical reason whatsoever.
Slashdot Mirror
Hi Dominux, A ground-to-orbit vehicle is, indeed, going to have to have a large mass (read rocket equation), especially since small rockets are more greatly penalized by air resistance. That's why some teams are going for rockoons, as you mentioned (they were used for very cheap sub-orbital flights back in the 50s, with payloads of a few kg). Once you bypass the atmosphere in this way, scaling laws are a lot more favourable, and you really don't want to have to lift more than necessary - a lighter satellite saves you fuel. I'm not sure what you mean about a little payload having to fling stuff or have energy imparted - the little payload is the satellite, not the launch system. You can use as much mass as you want in the launch system - the nanosat just has to stay in orbit, for which it doesn't need to do anything by way of propulsion. Best, Paul
Hi all, Wow - this thread has grown fast. A few quick answers to some points raised: 1) Why? What use is it? - For fun, and none at all, in that order. Also to prove that the world isn't run by accountants and safety officers. 2) 20 grams is too light. - No it isn't. We're beyond valves. 20 grams is plenty for a half-watt transmitter, a few square cm of solar panels, and more. Most entrants are looking to put video on their satellite (you can get camera modules weighing less than a gram). Some entrants are going for optical signalling. Either way, it's not really a problem. 3) "Other" applications/ICBMs etc - So, what? We're supposed to say 'nobody is allowed in space because there are terrorists who could use this technology'? If so, they've already won, haven't they? 4) Space junk - Yes, we'll be adding one or two pieces to the tens of thousands already up there. However, N-Prize entrants are mostly aiming for low (sub-200km) orbits, which will decay quite quickly. 5) Feasibility at the price - it's on the borderline of possiblity, using either single-use launchers OR using a small recoverable launcher (in which case, you can spend what you like on the launcher, and only the fuel and refurb costs count). 6) Cost of permits etc - If you want to get permits etc, then that's fine. Their cost is not counted as part of the budget (see full rules). 7) Come on, guys, loosen up a little! This is an invitation to play, and to try something almost impossible for no practical reason whatsoever.