NERVAfan

You can buy them from here (http://www.moss-stock-center.org/) but they are really expensive... I think we should save buying the "real thing" for the actual experiment (cubesat and Earthside control). I believe Mazon Del said he might be able to get some free though. Any "pre-work" we should probably do with other mosses.

That could actually work. I couldn't see complex life evolving on such a planet, but Hoth might be an Earth that went into a temporary Snowball Earth phase. Most stuff would go extinct, definitely, but some life would persist around hydrothermal/volcanic features. I'm not sure it would be able to support animals as big and energetic as the Tauntaun and Wampa, but... EDIT: The ice planet in Alan Dean Foster's Icerigger and sequels has a warm/cold cycle tens of thousands of years long, and the life switches between 'ocean age' and 'ice age' forms. There are plants that burrow roots through the ice.

Hal Clement had lots of great ones. In addition to Mesklin... Tenebra (from Close to Critical) is basically Venus with water and life - the temperature is constantly close to the critical point of water (thus the title) planetwide, so small temperature variations between day and night cause it to change from liquid to supercritical fluid. (I'm not sure life would actually be able to work in near-supercritical water since supercritical water tends to break down organic compounds... OTOH, I wouldn't have expected life to be able to exist at battery-acid pH and there are microbes that can do that). Dhrawn (from Star Light) is basically a super-jovian-sized rocky planet with liquid ammonia/water mixtures which have weird freeze/thaw properties. It doesn't have intelligent natives, I think there might be some simple plants though (haven't read the book in a while). Abyormen (from Cycle of Fire) is a planet in a binary system that passes between a cooler and a hotter sun; totally different forms of life exist on the planet in the different seasons (one is water-based and organic like us, I can't remember what the super-heated life uses).

Yeah, there's a huge huge difference between a machine which can make its own parts and a machine that can actually self-assemble. I'm pretty skeptical of self-replicating machines that would work on the Moon - life needs a water medium and generally has a much more restricted temperature range, as it does it by chemistry rather than assembly of macroscopic parts.

Oh, I'm pretty sure it's possible. In fact, you might be able to form a complete diet by combining different species of existing algae (spirulina is a complete protein, for example, though as a cyanobacterium you could argue it's technically not an "alga"). But I don't think an all algae diet would be much fun.

Yeah, it's not really that much thicker, though it looks like it if you compare the nominal values. But the nominal value for Mars is at a "datum" altitude and much of the planet is much lower than that. Mars datum altitude pressure is about 0.006 atm, but the highest pressure (in Hellas Basin) is around 0.016 atm, whereas Duna's nominal pressure at 0 altitude is 0.20 atm - but, as KerikBalm says, it doesn't quite get down to 0, so I'm not sure what the actual max is. In any case the difference is somewhat more than a factor of 10, but definitely not 30.

Well, there's also rover wheels (but those aren't on spaceships) and transmitting antennae. EDIT: I agree more power consumption would be nice.

Electric propellers would be cool, and likely would be sufficiently speed-limited to prevent making Eve returns too easy. I'd like to see those, combined with a change to the ion engine that makes it not work except in vacuum (or near vacuum).

But the average drag losses are so low because Earth launch vehicles are large. I believe Starman4308 is correct that a, say, 20kg rocket wouldn't be able to reach orbit on Earth even if it had the exact same mass ratio and Isp as a Falcon 9 or Proton. (Although you also need the rocket parts to survive the pressure and stuff, so I doubt a pencil-sized LV would work even on an airless body - unless it was a really low-gravity one.)

Unfortunately, the US signed the Outer Space Treaty (a huge mistake, IMO), which would prevent the US from claiming the Moon, so even if they did build a Moonbase they wouldn't call it anything like that.

I think the best near-term chance to find life in the Solar System is sampling the plumes of Europa/Enceladus - much more accessible than fossils on Triton. It wouldn't even require a landing if the probe could fly through a part of the plume thin enough to survive a flyby.

It will be destroyed on re-entry, we don't really have to worry about it hitting anything. And even if it somehow survived, it wouldn't hit the ground at some crazy speed due to terminal velocity (and it would be less dense than your average meteorite) so the damage would be less than that of a meteorite of comparable size, which are not that rare. (And the chances of an object dropped at random onto Earth hitting an artificial structure are actually quite low.)

Oh - I thought you could make the reactor fuel elements out of oxides to prevent O2 issues (the Atomic Rockets site talks about that, I think). A NERVA doesn't emit radioactive material unless something goes wrong, so wouldn't the pad be fine after the (terribly radioactive) active reactor departed?

Since we have a NERVA thread anyway... ...two questions. I love nuclear propulsion ideas (hence my username) but the problem is politics of launching nuclear material*. Could you mine thorium in the thorium-rich region of the moon to produce nuclear fuels? And, if so, what kind of specific impulse would a NERVA using liquid oxygen get? I know it wouldn't be good, but oxygen is easily available on the moon whereas hydrogen and other light elements aren't (except in the polar craters). Would it be good enough to SSTO from the Moon (at which point you could fuel with hydrogen from Earth or asteroids or whatever). *this is silly because we launch RTGs and plutonium is vastly more radioactive than U-235, but...

One of the Sandy Antunes books describes how to do that stuff DIY (including a low pressure/"vacuum" chamber). I will post more details when I have a chance, kind of in a hurry now. As for custom made stuff... my worry is that we are all in different parts of the world so it will be hard to get together and physically put stuff together. So if we can get enough money through the kickstarter (and I'm optimistic) it might be better to buy stuff rather than make it so that we can get this done in a halfway reasonable timeframe.

That does sound potentially problematic. And it would probably be cheaper without the deployable ones. So if we CAN do it without the deployable ones, maybe we should set that as the baseline, and consider the deployable ones as an "extra"/stretch goal if we get more money than we expect on the kickstarter. What will consume power? -Transmitter -Magnetorquers (attitude control) -Camera and IR LED(?) What else? Will thermal control be just insulation?

I made a Kerbin orbit which intersects the Mun's SOI. It survived 4 Mun encounters; the 5th pitched it into solar orbit. EDIT: Here's the orbit I started with Here's the last one that still intersected Mun's SOI: I have a bunch of intermediate screenshots too, I'll post them if you want more.

As for design - basic limits... Dimensions: 1U is limited to 10cm x 10cm x 10cm, maximum mass 1.33 kg, center of gravity must be within 2 cm of its geometric center in all 3 dimensions. Price: Not sure yet, depends on kickstarter so we can't really have a finalized design until after that, though yes, we certainly need a working design going in to the kickstarter. Power: I don't know what the limits are or how much we will need. K^2, do you know? Time/labor: This is tricky also. We are all in different parts of the world, so how will the physical assembly be done? A lot of things, like the basic structure & solar panels, we can buy "off-the-shelf" specifically for Cubesats, and I think we should so that we can focus our efforts on the mission-specific stuff. http://www.clyde-space.com/cubesat_shop/structures/1u_structures http://www.cubesatshop.com/index.php?option=com_virtuemart&page=shop.browse&category_id=1&Itemid=66 http://www.cubesatshop.com/index.php?option=com_virtuemart&page=shop.browse&category_id=17&Itemid=79

Yeah. One accident is not really a reason to impose more regulation on the industry. Virgin Galactic may be a dead end, but other companies aren't.

For airships, at least, it wasn't a single event. The Hindenburg gets all the press, but previous accidents had ended other nations' airship programs, e.g. the US loss of Akron & Macon.

Could you use argon instead? It is dramatically cheaper. This is something I've wondered about for a while. Cubesats deorbit quickly since they are small and have a high surface area/mass ratio. So why don't the paint chips and stuff deorbit really fast?

Glad to see you back K^2!

Is this still alive?

The transmitter will need much more than 100km range. That's the Karman line, but the drag doesn't really get practical to orbit till well above that. Also, it would be nice to not have to be directly over the ground station.

Wow. (10 characters)