http://www.esa.int/Our_Activities/Human_Spaceflight/Orion
Quote from: hektor on 12/04/2015 01:39 pmhttp://www.esa.int/Our_Activities/Human_Spaceflight/OrionIt looks like they didn't get the memo about the shiny coating on the capsule.
Quote from: Oli on 12/03/2015 06:57 pmQuote from: woods170 on 12/03/2015 06:26 pmYou make the mistake of assuming that SpaceX would, under equal requirements, come up with the same behemoth vehicle that NASA forced onto LockMart.I don't get it. So you think NASA forced the "behemoth" on Lockheed but would not force it on SpaceX? What's your argument again?The lunar Dragon from the Evolvable Lunar Architecture by the way is almost as heavy as Orion, all things included, and can only keep a crew of 4 alive for 14 days (not that I trust the study, but its the only one I know of).Two major flaws with your argument:- Orion and Lunar Dragon cannot be compared as apples-to-apples: Orion does not carry it's LAS all the way to lunar orbit. That add's quite a bit of mass to Dragon.- No actual input for the Evolvable Lunar Architecture actually came from SpaceX, so all mass figures for the Lunar Dragon, including those of the required modifications are to be taken with quite a bit of salt.
Quote from: woods170 on 12/03/2015 06:26 pmYou make the mistake of assuming that SpaceX would, under equal requirements, come up with the same behemoth vehicle that NASA forced onto LockMart.I don't get it. So you think NASA forced the "behemoth" on Lockheed but would not force it on SpaceX? What's your argument again?The lunar Dragon from the Evolvable Lunar Architecture by the way is almost as heavy as Orion, all things included, and can only keep a crew of 4 alive for 14 days (not that I trust the study, but its the only one I know of).
You make the mistake of assuming that SpaceX would, under equal requirements, come up with the same behemoth vehicle that NASA forced onto LockMart.
Quote from: woods170 on 12/04/2015 08:06 amTwo major flaws with your argument:- Orion and Lunar Dragon cannot be compared as apples-to-apples: Orion does not carry it's LAS all the way to lunar orbit. That add's quite a bit of mass to Dragon.- No actual input for the Evolvable Lunar Architecture actually came from SpaceX, so all mass figures for the Lunar Dragon, including those of the required modifications are to be taken with quite a bit of salt.- Dragon's LAS engines and fuel are used for LLO insertion/departure.- I agree, the cost projections are silly and they assume 324s of ISP for the SuperDracos, so I don't trust the study at all. Too "optimistic".
Two major flaws with your argument:- Orion and Lunar Dragon cannot be compared as apples-to-apples: Orion does not carry it's LAS all the way to lunar orbit. That add's quite a bit of mass to Dragon.- No actual input for the Evolvable Lunar Architecture actually came from SpaceX, so all mass figures for the Lunar Dragon, including those of the required modifications are to be taken with quite a bit of salt.
Quote from: Oli on 12/05/2015 04:18 pmQuote from: woods170 on 12/04/2015 08:06 amTwo major flaws with your argument:- Orion and Lunar Dragon cannot be compared as apples-to-apples: Orion does not carry it's LAS all the way to lunar orbit. That add's quite a bit of mass to Dragon.- No actual input for the Evolvable Lunar Architecture actually came from SpaceX, so all mass figures for the Lunar Dragon, including those of the required modifications are to be taken with quite a bit of salt.- Dragon's LAS engines and fuel are used for LLO insertion/departure.- I agree, the cost projections are silly and they assume 324s of ISP for the SuperDracos, so I don't trust the study at all. Too "optimistic".Have you even bothered to read that study properly?- If you had you would have noticed that LLO insertion is not done by Dragon's LAS engines but by the still-attached Falcon 9 second stage.- LLO departure (aka Trans Earth Injection) is done by Dragon's LAS engines using propellants being drawn from a second attached trunk.- The propellants stored in the Dragon service module (Dragon's own, internal propellant supply) is exclusively reserved for LAS duties and Earth propulsive landing. So my point, that Dragon carries it's LAS systems (including the needed propellants) all the way to the moon and back to Earth again, stands. It also means that comparing lunar Orion and lunar Dragon on weight alone is not apples-to-apples.
- The propellants stored in the Dragon service module (Dragon's own, internal propellant supply) is exclusively reserved for LAS duties and Earth propulsive landing.
Quote from: woods170 on 12/07/2015 06:33 am- The propellants stored in the Dragon service module (Dragon's own, internal propellant supply) is exclusively reserved for LAS duties and Earth propulsive landing.This is incorrect. Once launch is successful, what would have been used for LAS (all of it) is split up between mission propulsion needs (orbit/trajectory adjustment and attitude) and propulsive landing. There is no separate propellant supply for the Draco thrusters.
Quote from: Lars-J on 12/07/2015 06:29 pmQuote from: woods170 on 12/07/2015 06:33 am- The propellants stored in the Dragon service module (Dragon's own, internal propellant supply) is exclusively reserved for LAS duties and Earth propulsive landing.This is incorrect. Once launch is successful, what would have been used for LAS (all of it) is split up between mission propulsion needs (orbit/trajectory adjustment and attitude) and propulsive landing. There is no separate propellant supply for the Draco thrusters.No. In the quoted study it is assumed that the propellant in the service module is reserved for LAS and Earth landing duties.It does not matter if this not actually the case. What matters is what assumptions are made in the study.
Quote from: woods170 on 12/07/2015 09:11 pmQuote from: Lars-J on 12/07/2015 06:29 pmQuote from: woods170 on 12/07/2015 06:33 am- The propellants stored in the Dragon service module (Dragon's own, internal propellant supply) is exclusively reserved for LAS duties and Earth propulsive landing.This is incorrect. Once launch is successful, what would have been used for LAS (all of it) is split up between mission propulsion needs (orbit/trajectory adjustment and attitude) and propulsive landing. There is no separate propellant supply for the Draco thrusters.No. In the quoted study it is assumed that the propellant in the service module is reserved for LAS and Earth landing duties.It does not matter if this not actually the case. What matters is what assumptions are made in the study.Then the assumptions are wrong, and the study is questionable. How can propellant be reserved for LAS duties when the launch has already happened?
Quote from: Lars-J on 12/08/2015 04:28 amQuote from: woods170 on 12/07/2015 09:11 pmQuote from: Lars-J on 12/07/2015 06:29 pmQuote from: woods170 on 12/07/2015 06:33 am- The propellants stored in the Dragon service module (Dragon's own, internal propellant supply) is exclusively reserved for LAS duties and Earth propulsive landing.This is incorrect. Once launch is successful, what would have been used for LAS (all of it) is split up between mission propulsion needs (orbit/trajectory adjustment and attitude) and propulsive landing. There is no separate propellant supply for the Draco thrusters.No. In the quoted study it is assumed that the propellant in the service module is reserved for LAS and Earth landing duties.It does not matter if this not actually the case. What matters is what assumptions are made in the study.Then the assumptions are wrong, and the study is questionable. How can propellant be reserved for LAS duties when the launch has already happened?Launch escape requires ~300m/s. Landing 200m/s according to the study and deorbiting probably ~100m/s. It does add up.