NASA Unveils Strategy for Return to the Moon

mknewman writes to tell us that NASA recently announced plans to build a permanent base on the moon by 2024. The (still tentative) plans call for building the base on one of the moon's poles, which constantly receive light from the sun and have less temperature fluctuation. This base will start small in 2020 and grow over time with the hopes of eventually supporting 180-day stays and providing a jumping-off point to Mars."

Comments

Analysis of launch architecture; critiques

[FleaPlus]

Coincidentally, a pretty good article analyzing the planned launch architecture was published yesterday. Here's the link.

Additionally, aerospace engineer Jonathan Goff over at Selenian Boondocks has a post titled Lunar Much Sooner (and Better) which discusses a number of alternatives to NASA's current plan.

Finally, Selenian Boondocks also has another post about some things revealed by one of the architects of NASA's plans, suggesting that several of the design constraints imposed on the architecture may be somewhat dubious, (arguably) making the whole project much more expensive and unsustainable.

Re:less energy to go direct?

[KonoWatakushi]

Wouldn't it take a LOT less energy and time to go directly to mars, rather than stopping off at the moon and having to escape the gravity well of *two* planetary bodies before going to Mars?

Yes, it is absolutely stupid to stop at the moon on the way to mars. Until we have a completely self-sustained presence on the moon, with full manufacturing capabilities, it makes no sense.

In fact, it takes *more* energy to get to the moon than to mars. See http://en.wikipedia.org/wiki/Delta-v#Delta-v.27s_a round_the_Solar_System

Cost for supporting people is high.

[reporter]

Although the moonbase certainly captures the imagination, we must ask whether the high cost of supporting human life on the moon is worth the benefit. Could we get a better return on investment by not supporting human life and by using a crude robot (or remotely controlled mechanism along the lines of the 2 Mars rovers)? The robot would need neither oxygen nor a regulated environment at 72 degrees Fahrenheit. Since the Moon is much closer to the Earth than Mars, remote-control of the robot should have a delay on the order of seconds instead of minutes.

Further, all the money that we save in not transporting life-support systems to the moon could be invested in many more vital science/technology experiments -- conducted by our trusty robots.

In my opinion, sending people on far-away space missions will never be cost effective until we solve the biggest problem: the speed of our space vehicles. They need to be so fast that going to and from Pluto should take no more than an hour. If your spaceship blows a fuse near Jupiter, NASA can send a space taxi in 15 minutes to give you a lift.

A while ago, SlashDot reported on plans by the US Air Force to utilize Heim theory to build a warp drive for space travel. The news about these plans seem to have disappeared from the popular press' radar. Does anyone have more information about progress on this exotic project?

Re:Cost for supporting people is high.

[testadicazzo]

+5 for informative? wow... if I had mod points that would get overrated.

sorry, that was pretty polemic. Your post and the rating it got show however, a lack of understanding of both physics, and the process of scientific discovery and eventual engineering.

A quick google search reveals tha the distance of pluto (presumably average distance) is 5.4 light hours. A light hour is the distance light can travel in an hour. It's also the shortest possible time anything can get from point a to point b as dictated by the fundamental limits of the universe as best we currently understand them. So travelling at the speed of light, which we are so very very far away from being able to achieve, we could get to pluto in 5.4 hours. For frame of reference, the fastest manned spacecraft to date is appolo 10 at 11000m/s (3.7e-5 c, a pretty impressive feat actually).

What are the issues facing high speed space travel?

First off you have the limitation of the speed of light. It might be there is some fancy sci-fi solution to this limit, but we don't even have a theoretical idea of how to approach the problem, so until there's a major revolution in physics (it could happen, it does from time to time) you're stuck with it.

A second issue is the problem of the energy required to accelerate a body to sufficiently fast speeds. This is the issue your Heim reference addresses. Well, another consequence of relativity is the mass of a body increases as you accelerate it. This means that the closer we get to light speed, the more force required to accelerate a given body by the same amount (f=ma, but a=a(v)!). Practically speaking this imposes another limitation on the speed we can accelerate to. To keep it simple, lets say we it really is possible to use this Heim stuff to overcome the limits of the rocket equation (extra mass for extra acceleration, yuck!). Well great. But we still don't even understand the theory properly, let alone have a working prototopy, so that's years and years away, and because of relativity we probably can't hope for better than ~.001c as maximum speed. That means 5000 hours at max speed to pluto.

But we haven't addressed acceleration yet, which is my point 3: The human body can only withstand so many G's (1g = earth's gravity, a unit of acceleration, 9.8m/s^2). the space shuttle accelerates at 3G which uncomfortable but doable (note that special materials were developed as part of the space program to reduce the impact of acceleration, for example tempur. These materials now have civilian applicatons). The detonator at thorpe park goes to -5.5g. Wikipedia says the highest g force sustained by humans were (voluntary 46.2g astronaut john stapp, involuntary 180g F1 driver David Purley in an accident). But surviving high g's for a short time and for a long time are different things. We'll take a n aggressive estimate and say we could accelerate at 5g's sustainably. To reach .001c with 50g's would take .003e8 m/s / (5 * 9.8m/s^2) ) ~= 8 hours (neglecting relativistic effects, real time would be longer... lets say we can increase the force arbitrarily to compensate for relativity, again more new physics needed). So we need 16 hours to reach that speed, and another 16 hours to decelerate at the other side, means 16 hours accelerating and decelerating, and I'm neglecting more relativity here, but again on the aggressive side.

My next point is often neglected. What happens if you hit a little meteorite (It could be the size of a pebble, or even just a little cloud of dust). If that smacks into you at .001c relative velocity, you can bet it's going to do a lot of damage, even without considering relativistic mass. Think about how much damage small meteors do impacting earth at terminal velocity, which is probably at .00001 c or something... So we need shielding technology. Think about how much trouble the shuttle has with it's shielding tiles...

The up

Re:The plan will adapt to commercial developments.

[WindBourne]

Well, it appears that Zubrin is pushing for us to go onto Mars. The nice thing about all this, is that Zubrin and the mars society probably will convince some billionare (or 2) to invest in sending us to Mars. In doing so, much of the same tech that goes to the moon will work on mars and vs.-versa.

In space "direct" != "efficient"

[Cordath]

A direct transfer orbit (which is nowhere near a straight line) to Mars is the fastest way to reach Mars, but it's also one of the least fuel efficient ways. For this reason, large payloads such as the orbiter, rover, etc. have been sent to Mars via gravity assisted transfer orbits instead. These usually involve multiple trips around the sun and a couple close passes with other planetary bodies. If the payload goes past a planet or moon at just the right angle it will sling-shot around, effectively stealing momentum from the body. (don't worry, planets have plenty to spare) Go watch Star Trek IV to get the hollywood version. Gravity assisted transfer orbits are more difficult to plot, far far slower, and overall just a PITA, but there isn't any other option at the moment. Even if we had the money to spare nobody makes rockets big enough to send large payloads to Mars "directly".

Unfortunately, sending humans to Mars via gravity assited transfer orbits is not as easy. It's a much longer trip, so unless we sort out that suspended animation gig soon they would need much more food, supplies, etc.. That means more mass and more fuel, so a direct transfer orbit starts to look more economical for human travellers. As an added bonus, they don't spend several years in deep space, probably much closer to the Sun for much of their journey facing who knows what kind of added health risks. Given that there's little chance we'll ever build a rocket big enough to blast off directly for mars,we'll have to assemble the ship that goes to mars in orbit or on the moon. The moon's low-gravity environment may well prove to be an easier and safer environment for assembling an interplanetary space vessel. The moon is only about 1.2% as massive as the Earth so it's not that much of a "detour".

Correction

[volpe]

Crap, I forgot a square root in there. The required speed is 0.9696c. Sorry.

Heim theory may permit "warp drive"

[maddogsparky]

http://space.newscientist.com/article/mg18925331.2 00

The above article at the above link has a quote indicating that physical constants may be different if one were to travel along the different dimensions described by Heim Theory. If that was the case, the speed of light may be raised and the trip to Pluto shortened. Note that this would not actually require traveling faster than light, just faster that light as measured in "our" vacuum.

Think of it as a real theory which predicts warp-drive-like effects.