Quote from: Robotbeat on 03/30/2016 08:24 pmAn ICE is a really bad idea. Batteries work great. Solar panels also work great. 100 days is much too long to be using a ICE. An ICE throws away 70-80% of your energy. At least a fuel cell only throws away half. And you already have to throw away about half your energy to produce the methane and oxygen in the first place. So you're left with a round-trip efficiency of between 10 and 25%, ie you're left with only one tenth to one fourth of the energy you started with. Bad bad bad. Solar panels, on the other hand, are producing energy and are also improving all the time.I take it this applies to ACES IVF system as well? AIUI, its powered by a Roush Racing built ICE.
An ICE is a really bad idea. Batteries work great. Solar panels also work great. 100 days is much too long to be using a ICE. An ICE throws away 70-80% of your energy. At least a fuel cell only throws away half. And you already have to throw away about half your energy to produce the methane and oxygen in the first place. So you're left with a round-trip efficiency of between 10 and 25%, ie you're left with only one tenth to one fourth of the energy you started with. Bad bad bad. Solar panels, on the other hand, are producing energy and are also improving all the time.
It's hard to imagine Elon Musk taking SpaceX down the internal combustion engine road (i.e., Tesla, Giga-battery factories, Solar City, ZBO Methlox, minimal mass-to-orbit limitations, etc.), but the remaining ACES/IVF concepts are great and almost can be assumed to be part of BFS/MCT.
Quote from: AncientU on 04/03/2016 03:37 pmIt's hard to imagine Elon Musk taking SpaceX down the internal combustion engine road (i.e., Tesla, Giga-battery factories, Solar City, ZBO Methlox, minimal mass-to-orbit limitations, etc.), but the remaining ACES/IVF concepts are great and almost can be assumed to be part of BFS/MCT.Elon did say that you can make all modes of transportation electric on the exception of rockets. A rocket engine by definition is a combustion engine, adding an internal combustion engine to MCT is no big deal.Kaoru
Quote from: kaoru on 04/04/2016 12:36 amQuote from: AncientU on 04/03/2016 03:37 pmIt's hard to imagine Elon Musk taking SpaceX down the internal combustion engine road (i.e., Tesla, Giga-battery factories, Solar City, ZBO Methlox, minimal mass-to-orbit limitations, etc.), but the remaining ACES/IVF concepts are great and almost can be assumed to be part of BFS/MCT.Elon did say that you can make all modes of transportation electric on the exception of rockets. A rocket engine by definition is a combustion engine, adding an internal combustion engine to MCT is no big deal.KaoruI imagine the advantage of using an ICE is much bigger with LH/LOX than methane/LOX. It is not that hard to get methane/LOX to zero boil off and purely for electric power I believe solar is the better solution, especially beyond LEO.
Quote from: JasonAW3 on 03/29/2016 02:12 pmAdding things like internally stored cargoWhere else would you put the cargo for a vehicle capable of EDL on a planet with an atmosphere?
Adding things like internally stored cargo
Quote from: JasonAW3 on 03/29/2016 02:12 pmGuys, what happened to "Keep It Simple Stupid"?...Not to disagree with the rest of your post, I'd like to suggest that by the time this thing gets built, Musk's and his engineers' concept of Simple will be interesting to behold. Also, completely aside, I'd note that that phrase, addresses stupid, which people building MCT are not
Guys, what happened to "Keep It Simple Stupid"?...
Here is the latest model of my design speculation. For context, the attached image shows the engineering module focusing on the lower part. Specifically I'm only showing the pressure vessel which would contain (not shown) IVF, Sabatier reactor, batteries, pumps/compressors, etc. which are serviceable. The very lower part would be storage/cargo containing hoses/lines, etc. to hook up the systems externally/on surface or to another module via the CBM ring. Outside the pressure vessel, would contain structure and tankage for various systems, mostly CH4, O2, CO2, etc.. The top deck (which is not done yet) will contain removable water tanks, ECLSS, and other life support systems. Total height as shown is 26.5 meters (87 feet) which obviously does not include the payload (aka crew decks or cargo/consumables/propellants).Kaoru
Hi! Elon just said this on Twitter, do we think he could be talking below the $500,000 point?https://twitter.com/elonmusk/status/718598761832968192"Tickets to orbital hotels, the moon and Mars will be a lot less than people think."
Quote from: Craig_VG on 04/09/2016 01:26 amHi! Elon just said this on Twitter, do we think he could be talking below the $500,000 point?https://twitter.com/elonmusk/status/718598761832968192"Tickets to orbital hotels, the moon and Mars will be a lot less than people think."First time Elon talking about orbital hotels and the moon, to my knowledge.
I don't think the Moon is a necessary step, but I think if you've got a rocket and spacecraft capable of going to Mars, you might as well go to the Moon as well - it's along the way. That's like crossing the English Channel, relative to Mars. So, it's like, if you have these ships that could cross the Atlantic, would you cross the English Channel? Probably. It's definitely not necessary, but you'd probably end up having a Moon base just because, like, why not, ya know.
Quote from: Craig_VG on 04/09/2016 01:26 amHi! Elon just said this on Twitter, do we think he could be talking below the $500,000 point?https://twitter.com/elonmusk/status/718598761832968192"Tickets to orbital hotels, the moon and Mars will be a lot less than people think."First time Elon talking about orbital hotels and the moon, to my knowledge. Might indicate a shift towards more "attainable" goals. As for "what people think". NASA will pay $58m per seat on average to LEO. That's the reality.