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NASA Vets & Administration Clash Over Moon Plans
mattnyc99 writes "There's a serious feud brewing this week over the Bush administration's plan for a manned mission to the Moon as an eventual stepping stone to Mars. The Planetary Society, a top group of former mission managers, space-based scientists and NASA astronauts argues, is set to rebuke the Moon plan at a conference next month in favor of hopskotching an asteroid on the way to the Red Planet. Agency chief Michael Griffin issued an abnormally strong response to the society, calling it an overly political criticism of Bush for a plan that he says was 'the best legislative guidance NASA has ever had.' Either way, it's clear that the stars are aligning for the whole space race to be reconsidered as a new administration steps into the White House. So far Clinton and Obama (who just added his) are the only contenders with space proposals."
Weird, they don't even address any of the technical of economic objections to the Moon vs Mars mission. The article misses a lot of key points.
1) There is very little technical overlap in designs between a lunar and martian based program. The Moon has no atmosphere. That means no atmospheric braking. A lander landing on the Moon is radically different than one landing on Mars since the lunar one has to use only rockets to slow its descent. The Martian one can use rockets and parachutes as well as glide. Also, the lack of an atmosphere means that the Moon can not as easily provide oxygen or fuel as Mars, where those products can be pulled directly from the atmosphere. The Moon requires regolith mining to obtain any materials.
2) The transfer vehicle to the Moon is going to be able to complete the trip within 120 hours, or 240 hours if you have to do a return. That is easily within the range of not needing to recycle. You can just load up with consumables and then replenish at either end of the trip. The Martian vehicle will have to have some pretty hefty recycling technology.
3) The day/night cycle on the Moon is vastly longer than that of Mars. Mars is pretty close to that of Earth. Solar power is not even remotely practical on the Moon. (Except in the polar regions where it s theorized that would be possible to find spots where you have continual daylight). If you want to go somewhere other than the poles on the Moon for any duration, you are looking at needing a new generation of nuclear power. Which would also be useful on Mars, but there is a tradeoff there in terms of mass and other factors.)
4) I am back to "There is no atmosphere on the Moon" because it keeps impacting multiple areas. One of the problems that needs to be solved is HVAC type issues. Keeping things warm or cold. The Moon has no atmosphere, hence no convective heat transfer. All heat transfer is radiative or conductive. That necessitates a completely different thermodynamic paradigm than would be possible on Mars.
5) In terms of Human factors, the Moon is 1/6th gravity and Mars is 1/3th. That means items on Mars weighs twice as much as that on the Moon. The lunar space suits can not be worn on Mars as they are too heavy. New ones need to be designed. (We're also back to "The Moon has no atmosphere". Space suits need to be able to maintain a steady temperature inside. Since a lunar space suit is essentially a thermos when you consider it is in vacuum, all you have to worry about it shedding excess heat. On Mars, you are essentially enveloped by a fluid - the atmosphere - which has a temperature and can carry away excess heat.)
Actually, the reason for the asteroid mission instead of the lunar one is simple. It will require essentially the same type of spaceship that is required to get to Mars. The lunar base only has about 20% overlap with Mars technologies and - honestly - for those 20%, Earth is as good an analog as the Moon. When you develop a technology to go to the Moon, that is what you are developing. You are not developing one for Mars.
Essentially, you get the Moon and Mars for only twice the amount as getting the Moon or Mars.