Yeah, I do actually. If it's Solar Flare radiation. To effectivly stop that kind of radiation you need about 12cm of water or the equivilant. On Mars, the CO2 in the atmosphere gives you 21 grams of protection looking straight up, or about 65 grams on average, so solar flare radiation isn't really a problem, even if you camp out in a clear plastic bubble on the surface.MKSheppard wrote:You think 60 pascals of atmospheric pressure will offer any appreciable protection from radiation? Dirt is cheaper in both locations, and you can simply pile up more in both locations.eion wrote:What Mars' atmosphere does offer is some very nice free radiation shielding.
But eion, I hear you say, what about Cosmic Rays? Well, those are a bit more of a bother. Instead of 12cm of water for protection, you'd need several meters of water to do the job. Since it just isn't possible on a spacecraft to provide that kind of protection at the moment, travelers are stuck taking that extra 15rem for the 6 month trip to Mars, and 15rem for the trip back. But once you get there, it's a different story. Throw out half the radiation because you've got a planet under you. That average of 65 grams of atmospheric protection cuts the radiation down by almost half again, which leaves us with about 10rems per year without any additional protection.
That's kind of a high level, higher than what a nuclear worker would be permited in one year, but the risk isn't all that great considering. A 40 year old woman (and women being at greater risk than men) at 10rems a year would take 60 years to accumlate enough radiation to give you a 10% chance of getting cancer within the next 30 years, i.e. by the time you're 130 years old, and probably already dead. Astronauts flying for 60 years face far bigger risks than radiation.
If you're really worried about 10rems a year for our Martians, you can cover (note cover, not bury) the hab roof in a half meter of sandbags and surround it with bags of borated ice. The roof alone will take you down to 6rems a year.
I agree, but then we're talking about greenhouses, not your bedroom. And by the time our Martian colony wants to build larger inhabitable domes, the cost of the glass or thicker plastic material won't be an issue.MKSheppard wrote:Repeat after me: I will not place large transparent domes with large habitable volumes in a hazardrous environment.
Do you have 500 megawatts of spare power sitting ready to go on the Moon that I don't know about? Because that's how much you'd need to grow 250 acres of crops under minimal artificial light.MKSheppard wrote:Placing them underground in hydroponics/soilponics labs with precisely controlled lighting will ensure a greater turnaround in plant lifecycles, and as a bonus, you can access it even in times of heavy solar flares, and you gain extra protection against random events like meteorite strikes, a lander going awry, from knocking out your food/air supply.
You might be able to grow everything you need for a few people, but the power requirements are still 2 megawatts per acre. With the natural radiation shielding offered by the Martian Atmosphere, not to mention its nearly Earth-identical day/night cycle you can grow all you need with just 340mb of atmosphere under your plastic greenhouse dome (Plastic which you can make on Mars thanks to the abundance of hydrogen and carbon, two things the Moon lacks)
And any idiot who puts the landing ellipse of a lander within sight of your greenhouses should be shot on sight.
And who the fuck said anything about getting air from these plants? Sure they’ll make a bit, but we have near infinite chemical reserves to tap into for our oxygen on both Mars and the Moon.
Please identify the carbon or hydrogen in this graphHey wow, so does the lunar regolith.The atmosphere also offers abundant CO2 feedstock for oxygen extraction, fuel production, and ballooning.
Without carbon and hydrogen you cannot make:
-Food
-Fuel
-Silicon metal
-Plastics
And much much more. Guess what Mars has plenty of?
Also, what’s easier, shoveling tons of regolith into your oxygen reactor, or turning on a pump and sucking in as much CO2 as you want?
I honestly don’t know why we’re fighting about this. We agree. I don’t care what SDLV they use, Ares, Jupiter, DIRECT, Not-Shuttle C. They’re all good. Ares is nice because it’s ready to go. I don’t care. The point is not to throw away 30 years of experienced and tested hardware. I want them to keep making ETs, SSMEs, and SRBs. It’s the best heavy lift vehicle out there right now. Just a shame they designed the STS upside down and have to take an extra 68,585 kg up every time.Considering the shuttle production line has long been shut down it would cost more than Orion/Ares to restart the line.Hopefully Obama is slowly backtracking and will relaunch a SDLV (Shuttle Derived Launch Vehicle) program in the near-term
And since scientists get to direct NASA’s goals I guess that’s enough… Wait a minute, NASA isn’t one of those political footballs that gets tossed around and chewed on by both parties is it? They aren’t reliant on a public interest in their survival and future are they?Wrong. There's a long list of scientists who would KILL to have the heavy lift capability of Ares V to loft giant radio observatories, telescopes etc into space. Imagine something like hubble; but ten times bigger.but without an ambitious goal like Mars, a heavy launch vehicle just doesn't have the payload manifest to support the cost.
Those are excellent scientific goals, and worth every penny it takes to launch them. But not a single one of those require a mission beyond maybe the L2 point if we want to put them in the radio shadow created by the Moon. Developing heavy lift vehicles capable of launching a manned mission to Mars means we have developed heavy lift vehicles that can launch unmanned, and damn heavy, platforms to Lunar orbit.
NASA needs the Astronauts, and it needs them to be pushing the edges of discovery. The ISS may well turn out to be an excellent zero-gee research facility, but few kids are going to get excited about taking a trip down the street to the gas station, but tell them they’ll going to Disneyworld, and watch what they do. No one every names a high school after a robot.
I think you and I agree that Mars is our eventual destination. We both want to go to Grandma’s house, but you want to stop at the gas station on the way. I’m telling you we have enough gas and sodas to get to Grandmas, and she’s got enough to keep us happy while we’re there, and get us back. We don’t need a pit stop, it’s just going to cost us more money and slow us down.
Someone’s going to manrate at some point. It’s only a matter of time and money. If the government told them, “Do it for less than $30 mil per seat and you can keep the change,” I think you’d see a lot of interest. The Russians just set the bar, now we can let private enterprise limbo under it. We just have to stop paying them on a cost-plus basis and treat them the way any sane private employer treats a contractor.As a short term thing, yeah, we can pay the Russians $50M a seat while we wait for our new launcher to come online -- but Obama just lengthened the delay from five years to more like ten-fifteen years with his dumbassedry.I'm absolutely alright with the Russians charging us $50 mil a seat; gives NASA all the more incentive to fund commercial space-taxis.
And Space Taxis? LOL. I dare you to man rate SpaceX's Falcon 9 Heavy.
If I had my dream though, it’d be a scaled up version of the Black Colt rocketplane, which has some very attractive features for both the military and the private sector that’d be doing the bulk of our low-weight LEO work.