imho My little feasible pony is ... Lissajous...My big pony: ... Don't lick the moon. ... Meat upflux ...
...The key idea is that NASA's money is limited. ...The article notes that the total Near-Earth Asteroid Human Space Exploration Architecture, using the Commercial Launch/Propellant Depots program costs, is around $83 billion dollars. And, the total Near-Earth Asteroid the NASA Heavy Lift baseline program is about $122 billion dollars. And, the Apollo program costs were about $120 billion dollars.The article notes, "The black line in Fig. 12 represents the available exploration budget based on several assumptions like cancellation of the International Space Station program.Based on current budget projections for NASA, a flat line budget of $3B to $4B seems to be more realistic.Even with the commercial launch/propellant depothaving 32 percent less cost, either the Near-EarthAsteroid program needs to be scaled back or a lessaggressive program like lunar science and in-situresource development may be a better choice."From: Evolved Human Space Exploration Architecture Using Commercial Launch/Propellant Depots By Dr. Alan Wilhite, Dr. Dale Arney, Christopher Jones, and Patrick ChaiAt: http://www.newspacewatch.com/docs/IAC-12.D3.2.3.x15379-NASAStudy.pdf...
Where is the money coming from? Mars robot missions are going on a money diet. {snip}
Quote from: HappyMartian on 10/18/2012 03:12 pmWhere is the money coming from? Mars robot missions are going on a money diet. {snip}That's a good point. Most of the focus on the usefulness of depots has been for human missions, but would having depots in place allow for more cost-effective robotic missions to Mars and the outer planets?
Quote from: neilh on 10/18/2012 06:20 pmQuote from: HappyMartian on 10/18/2012 03:12 pmWhere is the money coming from? Mars robot missions are going on a money diet. {snip}That's a good point. Most of the focus on the usefulness of depots has been for human missions, but would having depots in place allow for more cost-effective robotic missions to Mars and the outer planets?Yes by the same means/methods. More throw-weight and delta-V if you refuel before starting. Manned and unmanned could benifit, as long as the depot has the right propellant and the transfer equipement is compatible.Of course that's "part" of the conflict generated by the idea of depots is which propellant and how they'd operate Randy
Quote from: neilh on 10/18/2012 06:20 pmQuote from: HappyMartian on 10/18/2012 03:12 pmWhere is the money coming from? Mars robot missions are going on a money diet. {snip}That's a good point. Most of the focus on the usefulness of depots has been for human missions, but would having depots in place allow for more cost-effective robotic missions to Mars and the outer planets?Working out how cost effective may be a complex question however it would allow heavier probes.On another thread it was calculated that an Ariane 5 could send 7 tonnes to EML-2. So by refuelling a 7 tonne dry weight probe can be sent to orbit Mars.The 7 tonne includes docking hardware, refuelling hardware, thrusters, fuel tanks and RCS. Transfer propellant, (Mars RCS propellant?) and Mars landing propellant could be refuelled at the EML-2 depot.
The ACES based depot was to be globally compatible. So for all this to work it does need to be globally compatible.
Do Lunar propellant ISRU and you can reduce the costs of needed Earth launchers for asteroid and Mars missions. Hauling propellant out of the Lunar gravity well to a high Lunar orbit for an asteroid mission staging assembly location is a lot easier than hauling it in the Earths deep gravity well all the way to L2. ...L1 and L2 are currently useless for what we can afford to do.
The delta-v between high lunar orbit and EML1 or EML2 is very, very small.
...Hauling propellant out of the Lunar gravity well to a high Lunar orbit for an asteroid mission staging assembly location is a lot easier than hauling it in the Earths deep gravity well all the way to L2. ...
Quote from: HappyMartian on 10/18/2012 02:12 pm...The key idea is that NASA's money is limited. ...The article notes that the total Near-Earth Asteroid Human Space Exploration Architecture, using the Commercial Launch/Propellant Depots program costs, is around $83 billion dollars. And, the total Near-Earth Asteroid the NASA Heavy Lift baseline program is about $122 billion dollars. And, the Apollo program costs were about $120 billion dollars.The article notes, "The black line in Fig. 12 represents the available exploration budget based on several assumptions like cancellation of the International Space Station program.Based on current budget projections for NASA, a flat line budget of $3B to $4B seems to be more realistic.Even with the commercial launch/propellant depothaving 32 percent less cost, either the Near-EarthAsteroid program needs to be scaled back or a lessaggressive program like lunar science and in-situresource development may be a better choice."From: Evolved Human Space Exploration Architecture Using Commercial Launch/Propellant Depots By Dr. Alan Wilhite, Dr. Dale Arney, Christopher Jones, and Patrick ChaiAt: http://www.newspacewatch.com/docs/IAC-12.D3.2.3.x15379-NASAStudy.pdf...L1 and L2 are currently useless for what we can afford to do.
Quote from: Robotbeat on 10/18/2012 11:48 pmThe delta-v between high lunar orbit and EML1 or EML2 is very, very small.I was actually attempting to look it up online but couldn't find it...
Quote from: HappyMartian on 10/18/2012 03:12 pmQuote from: HappyMartian on 10/18/2012 02:12 pm...The key idea is that NASA's money is limited. ...The article notes that the total Near-Earth Asteroid Human Space Exploration Architecture, using the Commercial Launch/Propellant Depots program costs, is around $83 billion dollars. And, the total Near-Earth Asteroid the NASA Heavy Lift baseline program is about $122 billion dollars. And, the Apollo program costs were about $120 billion dollars.The article notes, "The black line in Fig. 12 represents the available exploration budget based on several assumptions like cancellation of the International Space Station program.Based on current budget projections for NASA, a flat line budget of $3B to $4B seems to be more realistic.Even with the commercial launch/propellant depothaving 32 percent less cost, either the Near-EarthAsteroid program needs to be scaled back or a lessaggressive program like lunar science and in-situresource development may be a better choice."From: Evolved Human Space Exploration Architecture Using Commercial Launch/Propellant Depots By Dr. Alan Wilhite, Dr. Dale Arney, Christopher Jones, and Patrick ChaiAt: http://www.newspacewatch.com/docs/IAC-12.D3.2.3.x15379-NASAStudy.pdf...L1 and L2 are currently useless for what we can afford to do.I read through the paper again and I believe you misunderstood the passage you keep on citing. The passage isn't describing (presumably robotic) lunar science and ISRU as alternatives to establishing depot(s) at EML2, but rather as alternative activities that you can use an EML2 depot -for-.