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View Full Version : No Moon Missions, That's a Relief



Fraser
2010-Feb-01, 07:10 PM
The rumors were true, Constellation is cancelled. No Ares 1 crew vehicle, no Ares V heavy lifter, no Altair lander. No bases on the Moon, and no human exploration of Mars. NASA is canceling the human return to the Moon.Good.(...)Read the rest of No Moon Missions, That's a Relief (561 words)© Fraser for Universe Today, [...]

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Gerald McKeegan
2010-Feb-01, 08:44 PM
Sorry, but I think that column of smoke you see off in the distance is NASA's funeral pyre. The "bold new approach" with no clear direction of objective will just lay the groundwork for more cutbacks and downsizing in the future. When Bush announced the "return to the moon" plan in 2004, I bet a friend $5 that we'd fail to execute. Rather than collect my $5 today, I'm going to make a new bet: Once NASA pulls out of the ISS program in 2020, there will be no more NASA human spaceflight program.

BigDon
2010-Feb-01, 10:10 PM
How could that man do that to his own children? Take away the most fantastic legacy he could have given them?

R.A.F.
2010-Feb-01, 10:29 PM
The "bold new approach" with no clear direction of objective will just lay the groundwork for more cutbacks and downsizing in the future...snip...Once NASA pulls out of the ISS program in 2020, there will be no more NASA human spaceflight program.


Unfortunately I agree. Looks like the chinese will inherit the Moon. Serves us right for being so short-sighted.

IsaacKuo
2010-Feb-01, 10:49 PM
I'm more excited about what's in the budget than I ever was about what's out.

We need space infrastructure, like in-orbit refueling and solar electric space tugs. With that infrastructure, we will make space exploration more affordable--both manned and unmanned exploration--and this will be a true step toward permanent manned habitats (hopefully in places that actually make sense, like Earth orbit).

Jerry
2010-Feb-02, 12:33 AM
Last time I checked, to refuel, you need a fuel dump. Electric space tugs? Newton still requires something to tug againsts. What is missing in both cases is the legs to get into space - near earth orbit of otherwise. Fuel dumps add nothing but complexity without addressing the biggest hurdle: The atmosphere.

SolusLupus
2010-Feb-02, 12:39 AM
Unfortunately I agree. Looks like the chinese will inherit the Moon. Serves us right for being so short-sighted.

The Chinese can have the moon. Division of labor: China goes to the moon, the US does science elsewhere.

Actually sounds like a good idea, if you ask me.

Ivan Viehoff
2010-Feb-02, 02:17 PM
I agree it is well cancelled. The money would be much better spent on Cassini style missions to Uranus and Neptune, etc, where we would learn a lot more.

We won't be sending men to Mars in your children's potential working life time either. Probably not their entire lifetime. The much higher gravity of Mars than the moon makes the return trip so very much more difficult. Just work out the payload and energetic requirements of it all. It will require very many separate spacecraft, probably with swarms of reserves too in case any single one is lost. We need to have a much lower Mars spacecraft failure rate even to consider it, even with provision of reserves. It will a very long time to acquire that kind of reliability. And we will need to be so very much richer for such a massively mission to be affordable.

IsaacKuo
2010-Feb-02, 03:30 PM
Last time I checked, to refuel, you need a fuel dump.
Yes. An orbital fuel dump could be used to support space missions. There are many possibilities. Obviously, it would be nice if we could acquire fuel from orbit--like with atmospheric scooping--but an orbital fuel supply can still be useful even if every gram of fuel ultimately comes from the surface of Earth.

For example, water is dense and requires much less overhead than liquid hydrogen to boost into orbit. An orbital fuel depot could use solar power to generate hydrogen and oxygen from water.

Or a solar electric thruster may be used to bring fuel from LEO to an elliptical orbit with little propellant. This would allow refueling of missions to GEO or beyond with a much better payload ratio.

Electric space tugs? Newton still requires something to tug againsts.
Umm...solar electric thrusters don't need anything to tug against. They use electric rocket propellant.

What is missing in both cases is the legs to get into space - near earth orbit of otherwise. Fuel dumps add nothing but complexity without addressing the biggest hurdle: The atmosphere.
The atmosphere is not a big hurdle. Sounding rockets offer access to LEO altitudes at a small fraction of the cost to orbit. The big hurdle is the inconveniently large delta-v to orbital speed.

Now, it would be nice if there were some magic wand which gave us cheap boosts to LEO...but there isn't. I've pondered various methods of assisting boost to LEO, but these schemes tend to involve both extreme technology risk and extreme investment for a given payload capability.

Space infrastructure to assist getting from LEO to GEO and beyond may not have as big a potential payoff as novel technology to get to LEO, but it offers a bigger bang for the buck right now. We need to look at what's possible and practical, and that means technologies which are at realistic levels of technology risk and initial investment.

The good news is that this technology and investment will likely assist in developing future technologies to get to LEO. For example, solar electric space tugs could be fitted with spray nozzles for inverted aerobraking (http://www.walthelm.net/inverted-aerobraking/). Or if we supply fuel depots with lunar regolith, then the regolith might be used to power kinetic impact powered rocket boost (sort of "inverted lithobraking", where the moon powder directly impacts an ablative pusher plate).

Or maybe there is no easier way to LEO than big dumb boosters. In which case our investment in space infrastructure to assist from LEO to beyond is still a wise move.

djellison
2010-Feb-05, 10:18 PM
more cutbacks and downsizing in the future.

NASA just gots its budget INCREASED. Not cutbacks. Not downsizing. MORE money.

What has been cancelled is a program that was failing, and burning money.