Map from a paper on Lava tubes. Dark blue dots are tubes.http://marsed.asu.edu/sites/default/files/msip_reports/Martian%20lava%20tubes.pdfAnd as a little decoration, my take on an elliptical dome
We present a map of the near subsurface hydrogen distribution on Mars, based on epithermal neutron data from the Mars Odyssey Neutron Spectrometer. The map’s spatial resolution is approximately improved two-fold via a new form of the pixon image reconstruction technique. We discover hydrogen-rich mineralogy far from the poles, including ∼10 wt.% water equivalent hydrogen (WEH) on the flanks of the Tharsis Montes and >40 wt.% WEH at the Medusae Fossae Formation (MFF). The high WEH abundance at the MFF implies the presence of bulk water ice. This supports the hypothesis of recent periods of high orbital obliquity during which water ice was stable on the surface. We find the young undivided channel system material in southern Elysium Planitia to be distinct from its surroundings and exceptionally dry; there is no evidence of hydration at the location in Elysium Planitia suggested to contain a buried water ice sea. Finally, we find that the sites of recurring slope lineae (RSL) do not correlate with subsurface hydration. This implies that RSL are not fed by large, near-subsurface aquifers, but are instead the result of either small ( < 120 km diameter) aquifers, deliquescence of perchlorate and chlorate salts or dry, granular flows.
I found a paper that links pit chains to a certain type of faulting. Distribution, morphology, and origins of Martian pit crater chains
Martian lava tubes, and do we have any evidence that there is plenty of the critical water resource nearby?
I think the water ice and the lava tubes are in different places...Water ice is at high latitudes and low altitudes, features possibly associated with lava tubes are at low latitudes and high altitudes - specifically the tharsis bulge and the big volcanoes there.
Quote from: Robotbeat on 10/14/2017 12:54 amQuote from: rsdavis9 on 10/14/2017 12:50 amAnd what will get to mars first. Earth movers(bulldozers) or tunnel borers?Just put the bigelow modules in the tunnel.Best to just forget about Bigelow for SpaceX's Mars plans, IMHO. The BFS itself is cheaper for habitable volume than a Bigelow module is, even including all the useless overhead of all the fuel tanks and engines and stuff.For the record, I'd bet on earth (regolith) movers, first.Yes, bulldozers first. Need to smooth regolith for landing pads, roads, and structures. Cut and cover for habitats would be an easy way to add protection. If there's not a convenient steep hill or cliff nearby, they'll need a bulldozer to cut into the regolith deep enough for the tunnel borers to get started.
Quote from: rsdavis9 on 10/14/2017 12:50 amAnd what will get to mars first. Earth movers(bulldozers) or tunnel borers?Just put the bigelow modules in the tunnel.Best to just forget about Bigelow for SpaceX's Mars plans, IMHO. The BFS itself is cheaper for habitable volume than a Bigelow module is, even including all the useless overhead of all the fuel tanks and engines and stuff.For the record, I'd bet on earth (regolith) movers, first.
And what will get to mars first. Earth movers(bulldozers) or tunnel borers?Just put the bigelow modules in the tunnel.
If you have pressurised habitats inside a dome, then you can get away with pressurising the dome a lot lower. 0.07atm is above the Armstrong limit, so no need for a pressure suit "outside", and the triple point of water is ~40°C, so you can have lakes etc. A breathing mask would still be required. External pressure at the bottom of a deep canyon such as Melas Chasma should be ~0.01atm.For a minimally breathable atmosphere you could probably get away with ~0.2atm.
Quote from: Dao Angkan on 10/15/2017 09:28 amIf you have pressurised habitats inside a dome, then you can get away with pressurising the dome a lot lower. 0.07atm is above the Armstrong limit, so no need for a pressure suit "outside", and the triple point of water is ~40°C, so you can have lakes etc. A breathing mask would still be required. External pressure at the bottom of a deep canyon such as Melas Chasma should be ~0.01atm.For a minimally breathable atmosphere you could probably get away with ~0.2atm.You could have pressurized habitats inside a partially pressurized dome, but the bigger question is why would one want to do that... it seems that on an apples-to-apples basis, partial-pressure domes provide less habitable volume for a higher lifetime cost and more system complexity. Of course, a partially pressurized dome would be good for a greenhouse.
a partially pressurized dome would be good for a greenhouse.
A dome is good for multiple reasons. First, it gives you pressure vessel redundancy. A big increase in safety.
Second: it can be pretty cheaply made, lightweight
It is only a pity that newbies who have not seen the threads on this may be left with the impression that you can put up a dome just like pitching a tent
Quote from: Robotbeat on 11/08/2017 02:28 amA dome is good for multiple reasons. First, it gives you pressure vessel redundancy. A big increase in safety.Except domes aren't pressure vessels, that's their problem.I'm not arguing against the idea of using a partial pressure environment to allow large volume at a lower cost (it might be useful, it might not, that's a different debate), just that domes are a really, really stupid way of doing it.Quote from: Robotbeat on 11/08/2017 02:28 amSecond: it can be pretty cheaply made, lightweightNot if you actually want to hold an atmosphere (even a partial one), then they need more construction to hold them in place than any proper pressure vessel. Making them more expensive, complex and fragile than alternatives.You can force domes to work, by creating over-engineered anchors, by sufficiently sealing the floor, by reinforcing the rim, etc etc. For what? To expensively gain the same volume that could be vastly more easily gained by using a proper pressure vessel.The only reason people suggest domes is that, like you no matter how many times we go over this, they always have this image in their heads that domes are "easy". Just throw together a few panels, or a plastic sheet, add some air, and viola! instant Martian/Lunar habitat. And, like you, no matter how many times we go into the details of why domes are just the dumbest concept for pressure-vessels, somehow as soon as the subject changes, they go back to that mental image of the easy dome on Mars or the Moon. It's almost like a very specific anterograde-amnesia (where people can't form new memories.)Can't you guys get a tattoo or something? Keep a special notebook? Have a little macro pop-up on your computer wherever you type d-o-m-e, with a quick summary of why domes are stupid, and a counter showing how many times it's had to do that?