Hey Raoul, ça va, ça va?

Un des peu des voix civiles dans cette discussion. C'est toujours un plaisir a discuter (au lieu de disputer) avec toi!

Et alors...
<<Asteroid detection:
Why not ESL1 and ESL2 ?...<snip>... And here comes Triana :-))))>>

There's nothing wrong with ESL-1 and 2 for asteroid detection, in fact it's probably a really good idea to have those locations covered as part of a network. By the same token, MSL-2 (Mars-Sun) would probably be a great spot for an asteroid belt watcher. We could even start getting good enough data to start trying to determine families and back-track to earlier, potentially larger objects (and determine whether there's periodicity in the break-up of those earlier objects, setting forth a timeframe of cosmic danger to the Solar System). Oooh, and a JSL-2 craft could watch the Kuiper Belt and Oort clouds for long-period comets (plus its on a low-energy trajectory from EML-1). and, and (see, this is why managers have to ride roughshod on engineers and scientists)

I'm not even going to talk about Triana. Silly navel gazing if you ask me. I think we should point it at something else. What, I don't know, but Earth from 1.5Mn km away? Come on, let's find something more interesting to point it at.

In the end, I feel there's no single solution to the issue, but it needs to be built, sooner rather than later. And while the engineers would probably love to go nuts on a systems design for the entire asteroid detection architecture, we'd likely end up with another space shuttle. Better to start slow and simple and learn now from experience, not computer models.

So why EML-1 to start?
-It's not too big a step, but still gets us beyond the cocoon of the Van Allen belts.

-There's really no inclination penalties for the different LEO orbits. At least once a day (I think it might be twice, I'll have to check) an ellipse superimposed on a LEO orbit can have an apogee that intersects with the EML-1. The same holds true for the return. No plane change dV penalty to get there.

-Going there is part of NASA's NExT plan (although the NExT plan couldn't figure out any really compelling reasons for going there, which is why it languishes in file cabinets)

-delta-V to land anywhere on the Moon is about 2.5-2.6km/s with no location penalty. Getting back is the same dV.

-It's an on-ramp for the Interplanetary Superhighways. Probes can be sent from EML-1 to either ESL-1 or 2 (or out into deep space) for effectively 0 dV. Plus, the trajectories can be plotted in such a way that the probe will travel out to the libration points, halo orbit them for a while, and then wander back to EMl-1 with effectively NO impulsive maneuvers (in an "ideal" situation, of course). Check out the work Martin Lo did on the Genesis mission for more details.

-Getting to AND from GEO requires less than 4 km/s dV, much cheaper than from LEO to GEO. 4 km/s capability also gets you to Mars.

-Free-flyer platforms launched from EML-1 can circumnavigate the Moon on low-energy trajectories and arrive back at EML-1 after some period for harvesting, with no impulsive maneuvers required, a wet dream for microgravity scientists and manufacturers.

-Very close fall-back position for lunar missions.

-And the list goes on and on. Fundamentally, the reason I picked EML-1 as the next logical "destination" is because it offers SO many levels of redundant capabilities, all of which offer direct utility and value for other missions besides asteroid watch.

-It doesn't have to be a crewed station at first, just a tended outpost. We can build up to a crewed station over time (the Chinese seem at least to have that part right).

<<The Moon:...>>

The Moon offers a wealth of industrial and scientific opportunities which are far too casually dismissed by, well, pretty much everyone. I'm not even going to get started 'cause there's not enough bandwidth for that spiel. But it does offer a lot more near- and medium-term utility for Earth than does Mars.

I often ask myself "Why do we spend soooo much money on terrestrial infrastructure for second-hand solar power?" The ONLY energy we get that is not is nuclear and geothermal. Everything else is a result of the Sun's energy, from wind and rain (for hydrothermal), to archaeophotosynthesis for petrochemicals and coal. So why don't we just go to the source and get free and unlimited solar energy en directe? Sure it will require a good bit of infrastructure, but think of the untold trillions that have been sunk over the last 150 years or so, worldwide, into the infrastructure that requires and operates on the internal combustion of fossil fuels.

Oil derricks, pipelines, oil tankers, railcars, processing refineries, distribution centers, storage tanks, automobiles, airplanes, on and on. Suddenly the strategic investment in solar power sats doesn't seem so daunting. An EML-1 station could conduct early trials (and who knows what materials efficiencies we'll find across the spectrum once we're unleashed from the tyranny of the atmosphere).

But the Moon offers vast resources that don't require us to tear apart our own planet, and will be effectively free after an infrastructure develops and scale is ramped up. Plus on the Moon there's just enough gravity to make the initial assembly of components easy, and also the benefit of vacuum for cold welding.

From a strategic standpoint, once you get your power generation capabilities into space, they're much harder to tamper with, at least in the near-term.

So I'm 100% with you on the Moon.

My concern is that if the Chinese get to the Moon first they'll grab the prime real estate at the South Pole. While they can't claim sovereignty, by the same treaty once they have a base there it CANNOT be interfered with. First come, first served (The Chinese know this, too).

<>

You know who I'd hate to be? The Captain that has to tell his crew on a Mars-bound voyage that oops, telemetry indicates the robotic factory that's been alone and untended on Mars for the last couple of years making our return fuel blew a gasket/got punctured by a micrometeoroid/wasn't serviced post-launch/whatever, and now all of our fuel is happily re-integrating into the rare Martian atmosphere. So our first job is to fix it and, well, it looks like we're going to be there a while.

Now that would really be a bummer.

My concern really, though, is an aerobraking maneuver (the crux of all the Martian dV arguments) with an object as large as one envisioned for a Mars mission. It's one thing to do it with a teensy, tiny little three-man capsule, quite another with a large lander. It could probably be done (I'd want a couple of dry runs first), but I just imagine that sort of thing giving senior management many, many gray hairs, because we certainly don't have a perfect record in that regard.

And again, what does it offer with regards to Earth-related benefits? If it's going to be a pain getting infrastructure to the Moon, it's certainly going to be a real pain getting it to Mars, and take a lot longer, too.

Should we go there? Absolutely! I firmly believe the greater the variety and diversity of human culture the better. Thing is, a culture will also develop on the Moon. Perhaps not as "good" a culture as the one that will develop on Mars, but extant nonetheless. The Martian Culture argument doesn't hold water either.

And speaking of water, we also happen to know that hydrogen and oxygen are on the Moon. The hydrogen may or not be in the form of water (I'm reserving judgement until we actually go and look), but it is there. That makes rocket fuel, that makes water. If we can get solar furnaces on the Earth up to 4,000 degrees Fahrenheit, we can liberate oxygen from the regolith with solar furnaces on the Moon. The water may not be as easy to get on the Moon, but are we doing this whole space thing because it's easy?

<<Search for life:...>>
Of what utility will finding life on Mars be? I've never heard a compelling answer, and it seems like quite an expensive endeavour to satisfy curiosity.

Personally, I have no doubt that life exists out there in some way, shape or form. If terrestrial bacteria can survive on the Moon then for crying out loud it makes sense that it's out there. My question is: "Why are we in such a hurry to find it RIGHT NOW?"

As I said, I'm waiting for the first pre-Solar System fossil. Now that will be really cool - far cooler than anything that could be found on Mars. Anything else will just confirm what I've long suspected, so why do we have to find out as quickly as possible?

I'd love to go to Mars, I'd just rather do it sensibly, as part of a long-term strategy to bring the benefits of and mitigate the dangers from space to Earth. That, at least, is something that I hope we could all agree on. To conquer the Solar System, in the words of Enjie Luan (from his verbal remarks to the SGF at UNISPACE III, that phrase is not in the printed copy that was handed out).

a toute a l'heure,
Ken