New Mars Forums

The wikipedia article says the ET is 46.9m by 8.4m diameter. Thats 2600m^3. To get 5200m^3 out of a 10m diameter tank, a tank length of about 66m is required.

Actually, the main tank of the Ares V is nearly there at around 60m, not including the upper stage tanks. Infact, I'd imagine you could, pad logistics permitting, mount two extra SRB's onto the Ares V, without increasing Max-Q or max heating over the space shuttle during launch.

That should be around 200T then.

Exactly. So how many tonnes is that?

No no, your not getting it (or maybe I'm missing something?).

What is the fundamental difference between 2 shuttle stacks melded into one, and 2 seperate shuttle stacks?

So thats twice as much payload, right?

Here's something I doodled in mspaint while thinking about applying the Delta-IV growth options to these new 10m diameter tanks and RS-68b engines. Enjoy.

What I'm suggesting here is 2 shuttle stacks melded into one. 4xSRB's on the outside, a main tank twice as heavy, and the equivalent of 6 SSME's underneath. The Space Shuttle doesn't have an upper stage, so I guess without one this 'duality'-booster should lift exactly twice as much as the shuttle stack, right? Whats that then?

If we added an upper stage, even more?

Your payload estimates seem too conservative to me.

Okay, could we just add 2 more SRB's to the Ares-V then?

You can see where I'm going with this though? Perhaps I could ask it like this: What is the best equivalent to 6 SSME's?

Here's what I'm thinking: During the first couple of missions, we'll use the basic Mars Direct or DRM mission profile. Later, after the first crews have safely returned, as part of each succesive mission, we'll implement an additional heavy-lift launch to deliver an additional supply vehicle to the surface.

The supply vehicle will contain spare parts for the hab, big drills, extra rations, etc. More importantly though, it'll have a small methane engine, or perhaps a fuel cell, and heaps of fuel. And last but not least, it'll have four really big tires around the outside.

This supply vehicle is then remotely driven towards the Hab, partially disassembled, then reassembled around the Hab (sort of like a bolt-on 4-wheeled cradle).

The Hab will keep its original long-range rover, as a contingency, but the roving Hab will likely either trace a path toward or around the ERV, depending on its landing proximity. Or, with the extra rations, you could allow the crew to keep on rovin' until the fuel gets low, setting a later ERV down ahead of them.

No radioactive power plants required. And yeah, it'll be a launch more expensive, but I think it'll be worth it considering the huge increase in science return (both from the mobile hab and the extra science equipment).

Plus, it'll be more fun!

Don't dig too deep, GCNR. Prove to me it won't work. I want to see some numbers.

No not 100% certainty. Never. What should be allowed though, is assumption.

If it looks like a pineapple, smells like a pineapple, and tastes like a pineapple, then you assume its a pineapple, right?

However, it wouldn't be agnosticism if there was no acknowledgement of at least a small amount of uncertainty. It could be a molecular assemblage of imitation flavor molecules on a starch-based substrate, a-la star-trek food replicator technology. But probably not.

How does this improve on fundamentalism?

Well, personally, I hope it enlightens us to the requirement of faith, and in turn, the ignorance of fundamentalism. Wow I just realized that most of you have no idea what I mean by that.

Fundamentalism = certainty.

Agnosticism = uncertainty, and don't you forget it.

Rational Agnosticism? = uncertainty, but its okay to make assumptions.

You make some good points, but I don't think any are real show-stoppers.

The Hab won't need to rove continuously. It'll stop for weeks at a time when it reaches a good science spot. It could even rove only at night, or at least when there's no decent science to do in the lab. (This thing'll be on the surface for 1.5 years, remember.)

As I've advocated before, any Mars Direct or similar plan could benefit a lot from an additional launch to deliver a cargo vehicle to the surface. Not only would this deliver the necessary components to modify the hab, but it could also deliver those large drills we need to, among other bits and bobs.

As for the power requirements: I think I'm as unsure as you are. We definately need to look into this. However, I'd like at least to do this much before dismissing the idea altogether. At the very least, I think this idea deserves to be brainstormed. I don't expect it to be immediately unquestionably adopted.

True, robots are/will be pretty good. But in order to guarantee good science, the robotic exploration phase may risk doing half the work. Anything left might amount to scraps in light of the order of magnitude capability difference between robot and man.

I suspect that in order to maintain a good case for manned exploration, thorough pre-scouting of the sites will be purposely minimized or omitted altogether. Otherwise the robo-fans will cry foul.

The idea of a super-long range rover presents a similar case. I think you get to the point where the rover becomes so big and comfortable that the astronauts compete for time between rover sorties and the hab. Then the leap from large rover to mobile hab (with small rovers) is small enough to step across.

Figuring how much tire contact patch a Mars Direct style hab should have will be a good first step.