...But there are many possibilities, e.g. neutral particle beam propulsion - a beam of neutral particles at almost the speed of light is fired at the spacecraft, it ionizes them and then uses magnetic fields to deflect them producing a very high Isp drive. The technology to do that is formidable!...
As suggested before, I think the $500,000 per passenger price could be achieved with high-performance light sails acclerated and decelerated by orbital lasers. These "lightcraft" could make the trip in a matter of days / weeks regardless of launch windows. The laser stations would have to be huge though, in the multi-GW range at least. The advantage is that these lasers could be used at all times. Chemical or solar electric rockets would be much slower and launch window constrained and thus not suitable for a reusable transportation system, which requires a high number of trips to recoup capital costs.
But there are many possibilities, e.g. neutral particle beam propulsion
Quote from: MikeAtkinson on 11/29/2012 08:13 pmBut there are many possibilities, e.g. neutral particle beam propulsionAnother possibility is teleportation. Russians perfected this technology long before they perfected oxygen-rich rocket engines. Using ethanol fuel, you get from point A to point B without remembering anything in between. Works great when travelling in Russia.
The ideal velocity for the particles (power-wise) is probably something like twice the relative velocity of the neutral particle and craft at impact.
Quote from: DLR on 11/29/2012 08:31 pmAs suggested before, I think the $500,000 per passenger price could be achieved with high-performance light sails acclerated and decelerated by orbital lasers. These "lightcraft" could make the trip in a matter of days / weeks regardless of launch windows. The laser stations would have to be huge though, in the multi-GW range at least. The advantage is that these lasers could be used at all times. Chemical or solar electric rockets would be much slower and launch window constrained and thus not suitable for a reusable transportation system, which requires a high number of trips to recoup capital costs. GW? Need much more than a Gigawatt, at least for the kind of payloads and timescales we're talking about. Terawatt, maybe?
If a Mars colony actually does take off, you'll see this topic discussed quite a bit. Prison colony... Australia II!
Quote from: Robotbeat on 11/29/2012 09:15 pmIf a Mars colony actually does take off, you'll see this topic discussed quite a bit. Prison colony... Australia II! Slave colony... America II!
Quote from: Robotbeat on 11/29/2012 08:54 pmQuote from: DLR on 11/29/2012 08:31 pmAs suggested before, I think the $500,000 per passenger price could be achieved with high-performance light sails acclerated and decelerated by orbital lasers. These "lightcraft" could make the trip in a matter of days / weeks regardless of launch windows. The laser stations would have to be huge though, in the multi-GW range at least. The advantage is that these lasers could be used at all times. Chemical or solar electric rockets would be much slower and launch window constrained and thus not suitable for a reusable transportation system, which requires a high number of trips to recoup capital costs. GW? Need much more than a Gigawatt, at least for the kind of payloads and timescales we're talking about. Terawatt, maybe?Multi-GW! Of course it depends on the speed and size of the craft ... and the technology used. If your optics are good enough you can utilise one photon several times by bouncing it back and forth between sail and emitter. ...
Quote from: Robotbeat on 11/29/2012 08:54 pmQuote from: DLR on 11/29/2012 08:31 pmAs suggested before, I think the $500,000 per passenger price could be achieved with high-performance light sails acclerated and decelerated by orbital lasers. These "lightcraft" could make the trip in a matter of days / weeks regardless of launch windows. The laser stations would have to be huge though, in the multi-GW range at least. The advantage is that these lasers could be used at all times. Chemical or solar electric rockets would be much slower and launch window constrained and thus not suitable for a reusable transportation system, which requires a high number of trips to recoup capital costs. GW? Need much more than a Gigawatt, at least for the kind of payloads and timescales we're talking about. Terawatt, maybe?Of course it depends on the speed and size of the craft ... and the technology used. If your optics are good enough you can utilise one photon several times by bouncing it back and forth between sail and emitter.
Quote from: DLR on 11/29/2012 09:25 pmQuote from: Robotbeat on 11/29/2012 08:54 pmQuote from: DLR on 11/29/2012 08:31 pmAs suggested before, I think the $500,000 per passenger price could be achieved with high-performance light sails acclerated and decelerated by orbital lasers. These "lightcraft" could make the trip in a matter of days / weeks regardless of launch windows. The laser stations would have to be huge though, in the multi-GW range at least. The advantage is that these lasers could be used at all times. Chemical or solar electric rockets would be much slower and launch window constrained and thus not suitable for a reusable transportation system, which requires a high number of trips to recoup capital costs. GW? Need much more than a Gigawatt, at least for the kind of payloads and timescales we're talking about. Terawatt, maybe?Of course it depends on the speed and size of the craft ... and the technology used. If your optics are good enough you can utilise one photon several times by bouncing it back and forth between sail and emitter. Whoa hold on. My alarms for perpetual energy claims are going off. How does bouncing it multiple times solve anything? One bounce won't get you anything less than 1000 bounces.
Quote from: mlindner on 11/30/2012 01:21 amQuote from: DLR on 11/29/2012 09:25 pmQuote from: Robotbeat on 11/29/2012 08:54 pmQuote from: DLR on 11/29/2012 08:31 pmAs suggested before, I think the $500,000 per passenger price could be achieved with high-performance light sails acclerated and decelerated by orbital lasers. These "lightcraft" could make the trip in a matter of days / weeks regardless of launch windows. The laser stations would have to be huge though, in the multi-GW range at least. The advantage is that these lasers could be used at all times. Chemical or solar electric rockets would be much slower and launch window constrained and thus not suitable for a reusable transportation system, which requires a high number of trips to recoup capital costs. GW? Need much more than a Gigawatt, at least for the kind of payloads and timescales we're talking about. Terawatt, maybe?Of course it depends on the speed and size of the craft ... and the technology used. If your optics are good enough you can utilise one photon several times by bouncing it back and forth between sail and emitter. Whoa hold on. My alarms for perpetual energy claims are going off. How does bouncing it multiple times solve anything? One bounce won't get you anything less than 1000 bounces.I'd assume that the frequency of the photon drops on each bounce, so that is where the energy is coming from, but I admit this is not my strong suite.
I add that the ticket price is one way, based on a line from a SpaceX employee giving a presentation (during questions afterward) that the $500k ticket price is "one way."
The key I was trying to figure out was, with volume, is it possible to get the cost of moving to Mars down to under half a million dollars, which is I think is - no-one can argue about the exact threshold, but I think that is about the threshold which enough people would save up money and move to Mars. I mean, that's how America got created, basically. They can come back if they like, if they don't like it, of course. You get a free return ticket. There's sometimes a debate about going to Mars one-way and whether that makes things easier, and I think for the initial flights perhaps, but long term, to get the cost down, you need the spacecraft back. Whether the people come back is irrelevant, but you must have the ship back because those things are expensive. So anyone who wants to return can just jump on.
Quote from: LegendCJS on 11/30/2012 12:51 amI add that the ticket price is one way, based on a line from a SpaceX employee giving a presentation (during questions afterward) that the $500k ticket price is "one way."Nope.QuoteThe key I was trying to figure out was, with volume, is it possible to get the cost of moving to Mars down to under half a million dollars, which is I think is - no-one can argue about the exact threshold, but I think that is about the threshold which enough people would save up money and move to Mars. I mean, that's how America got created, basically. They can come back if they like, if they don't like it, of course. You get a free return ticket. There's sometimes a debate about going to Mars one-way and whether that makes things easier, and I think for the initial flights perhaps, but long term, to get the cost down, you need the spacecraft back. Whether the people come back is irrelevant, but you must have the ship back because those things are expensive. So anyone who wants to return can just jump on.http://shitelonsays.com/index.php/transcript/elon-musk-the-future-of-energy-and-transport-2012-11-14