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#1 2018-07-22 19:20:46

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,854

Key Debates

I thought it might interesting, especially for new people here, to list some of the key debate fault lines on here (and if the mods like it, it could become a sticky). Here's my attempt at a summary:

  1. Pessimists v. optimists.     

Pessimists tend to think colonisation and terraformation of Mars is an extremely difficult task, one fraught with the possibility of failure.

Optimists think it's crazy to imagine that there is any big problem involved in getting to Mars and, once there, with all that land and all those resources, we will have no problem colonising the planet.  (I'm an optimist).

  2. Nuclear v. photovoltaic (PV) or solar power   

This is a recurring debate here.

Nuclear power enthusiasts point to its impressive energy density and reliability. They note how PV systems are seriously compromised during dust storms on Mars which can last for as long as 9 months.

PV enthusiasts note how PV power has been used successfully on Mars for decades, how flexible it is in terms of varying uses (transport, mining, exploration etc), and how lightweight modern printed PV is.

Some people argue for a mix of the two.

(I am a big PV fan. With back up from methane-based electricity generation and chemical batteries, we will be fine with that option in my view.)

3. Artificial gravity (AG) v. No  AG     

A lot of people argue we need an aritificial gravity system, at least for the transit to and from Mars, and possibly even on Mars. These people argue that the debilitating effects of zero G necessitate this.

Their opponents argue that space medicine and exercise regimes has greatly ameliorated the negative effects of zero G, and one can select for people with a good tolerance of zero G, plus once on Mars one can use weighted suits to mitigate the effects of the low G (0.38) on Mars.

(I favour the latter.)

4. Democratic v Autocratic     

What sort of government do we need on Mars and how soon?

There are in fact many shades of opinion. But one can see a pattern of those who think you can move to democracy very quickly and those who think autocratic, military style government is required.

(I tend to back the quick path to democracy route.)

5. Homesteaders v Centralists   

There are those who want to see Mars populated by lots of independent-minded homesteaders doing their own thing without interference from government.

Centralists think that is a romantic notion and that the realities of living in such a challenging environment require centralised direction, not eccentric homesteading.

(I am a bit torn between the two, but head normally wins over heart and I think Mars will be a v organised sort of place - think airplanes, airports, university campuses...not the rolling prairies. Maybe that would change once Mars is terraformed.)

6. Dead planet v. live planet 

Lots of people think Mars is a v. live planet with complex ecosystems ranging from bacteria to fully fledged alien "greys", or if not live now, it was in the past.

Others think it is a big lump of rock and has no life on it.

(I veer between the two, but am concerned if we think it genuinely a live planet, then there will be a big move to stop us exploring it.)

7. Chemical rockets v. other means of propulsion 

There are those who argue we need new and maybe novel forms of propulsion if we are ever going to successfully colonise Mars.

More conservative types (like me) argue the chemical rockets are there, we know they work, so let's proceed on that basis.

8.  Mars Now v. Moon First

This debate is probably a bit out of date now, since the BFR designs were announced by Space X, since they mean to use BFR for Earth transit, Earth orbital, lunar and Mars - and maybe beyond.

But this is still a slightly sensitive area of debate. Mars enthusiasts are always on the look out for someone trying to divert humanity away from the big prize towards lunar exploration or some such.

9. Artificial light agriculture v. natural light agriculture.

The idea of agriculture under natural light domes on Mars is a powerful one, and indeed was  one of the original motivations of Elon Musk - he wanted to see that developed.

But others point to the incredible amount of investment required to create and maintain such structures, certainly in the initial period of colonisation, when it might be more resource-effective to have multi-layered hydroponic agriculture in artificially lit enclosed spaces without windows. However, the counter-argumnet is that those pushing for hydroponics refuse to acknowledge the massive investment required to build and operate hydroponics, e.g. manufacturing appropriate nutrient solutions and providing much the much higher power requirement if it is artificially lit.

(I argue for a phased switch from initial artificially lit agriculture to natural light farming over a few decades.)

10. Mars Goldrush v. Mars dependency.

This goes back to no. 1 but concerns the Mars economy in particular.

The optimists (like me) think Mars will be flooded with investment through commercial sponsorship, TV rights, books sales, sale of regolith and meteorites found on Mars, film rights, university research grants, space agency projects, niche industries on Mars like luxury watch manufacture, art works on Mars, and a range of other revenue sources.

The pessimists think the Mars colony will be basically supplicants dependent on subsidies from big space agencies or billionaires like Musk.

I am of course an optimist!

Any more Key Debate topics to mention?

In view of the discussion below I am adding another fault line:

11. Space Xers v. Alternative Mission Designs

In the past, when the prospect of a Mars Mission seemed very distant, everyone was happy to advocate for their preferred mission design.  But the announcement of a real Space X mssion design that is now being built has changed the landscape. There are those who think we should focus on the Space X plan whilst others maintain that the Space X plan has flaws (potentially fatal some argue e.g. the difficiculty of landing a huge BFR rocket on unprepared ground on Mars) or is unlikely to be realised because it is too ambitious, and so we should continue to examine alternative mission architectures that might have a better outcome.

My own view is that discussion of alternative mission designs is now somewhat redundant, in view of the Space X project. I think it very unlikely anyone else will come up with a project that can deliver so much mass and people to Mars so quickly. So it is unlikely to be bettered from that point of view.  For the rest, I am an optimist and doubt the objections raised to Space X's architecture are insurmountable. It seems to me therefore that going over designs for smaller-style missions is really a waste of time and effort. It is more interesting  I feel to focus on Space X's mission and how that will proceed. However, this is really a matter of personal choice, not an issue of fact.

Last edited by louis (2018-07-28 03:35:59)


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#2 2018-07-22 20:40:46

kbd512
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Registered: 2015-01-02
Posts: 3,558

Re: Key Debates

1. Some of us are just realists.  The reality of this endeavor is that it is a severe test of our technology, ingenuity, and will to persevere.  However, a human presence on the red planet is only a matter of hard work and ingenuity.  There's nothing "impossible" about it.

2. I'm a fan of never running out of electrical power.  I don't care how it's supplied, but it had better be available at all times.  Of all possible fates, loss of electrical power is an incredibly stupid way to die in space.  Thus, I'm in favor of making use of all available electrical power generation technologies.

3. Science says humans were adapted to function best in 1g and I've never seen any science that contradicted that statement.

4. After the first two people set foot on Mars, they can decide what kind of government they should have.  Unless you're living there, you shouldn't have any say-so in the matter.

5. Any space exploration and colonization activity will demand lots of coordination and cooperation.  The fact of the matter is that homesteaders did cooperate a lot with each other just to survive.  Mars is not a place amenable to "going off to do your own thing".  There are so many ways to die there that the idea of not cooperating with your team mates or following the orders of your mission commander is absurd.

6. We're so stunningly ignorant of life on Earth that there's no way to know whether or not Mars has life, which is why we need to go there to find out.  The robots we've sent to other planets have only served to create more questions than they've answered.  Until we sent the robots, we were too ignorant to even know what questions to ask.  Exploration of the vast expanse of space demands the use of both robotics and humans.  Lately, there hasn't been enough emphasis on the human component to space exploration.

7. The use of high power electric propulsion makes the prospect of Mars exploration and colonization affordable.  The chemical rockets are just barely sufficient to get the job done at all, but yes, they also happen to work well enough.  Even so, the entire point of space exploration and colonization is to achieve a better result.  The use of electric propulsion is part of achieving a better result.

8. This is the "New Mars Forum", not the "New Moon Forum", so I would hope everyone here wants humans to go to Mars.  The moon happens to be a convenient nearby proving ground, so I think we should test new technologies there so that we know with some degree of certainty that the tech we want to send to Mars will function as intended.

9. The surface radiation environment is not amenable to human or plant life as it exists on Earth.  If we could make glass on Mars with sufficient thickness, this would be less of a problem.  There's no glass factory on Mars... yet!

10. Nobody flooded the moon with venture capital after NASA sent humans to the moon.  Why would it be reasonable to expect that Mars will be any different, at least in the short term?

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#3 2018-07-22 20:55:07

SpaceNut
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From: New Hampshire
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Posts: 19,183

Re: Key Debates

Sustainable independance of earth vast resupply capability to self dependance on Mars insitu materials.

Amend: This goes into mining and what materails and methods to be used for construction of above and below ground chambers for habitats, for food or for storage which include fuels, co2 or other energy forms.

Create and store excess for future needs, not consume then just because we can and do not over expand mars presence or population to numbers that can not be sustained.

Ability to adapt to harsh conditions being able to plan for hard times as they will happen.

Amend: the ability to use what you have to made what you need.

Begin self reliance on the ability to turn nothing into something to be able to create a return transport system that is mars born.

Plan to leverage mars to go farther into the depths of space as its gravity hole is less, as that is the giant leap for man kind.

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#4 2018-07-22 22:14:13

JoshNH4H
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From: Pullman, WA
Registered: 2007-07-15
Posts: 2,526
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Re: Key Debates

I quite like your list of central arguments and I think you've really captured the main axis of debates on the forum


-Josh

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#5 2018-07-23 19:18:37

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,183

Re: Key Debates

I think logical thinking is required to rule out those that are not important in each of our posts for first mission and add in those that are for future growth, continuance in base manning and lessening of risk to those that stay.

First mission is a Toehold mission to go with a safe return home, do some science, get samples, explore an area to allow for a reason to go back to this site, set up the experiments for future alterations from the plans used in the first mission to allow for expanding the efforts for the future at a lower cost and of sustainability to mans presence on mars.

Second mission is the Foothold mission in that insitu ISPP is set up for man's return flight home, Proving water and oxygen plants are setup plus running not only for safety but for a future mars return with even larger crews, A food growth greenhouse is setup and operational to provide the food needs based on want to grow the crew size and a continued exploration plus science about and of mars.

Third mission on are phased in settlement providing an even deeper root existance for man's future.

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#6 2018-07-24 19:15:44

SpaceNut
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From: New Hampshire
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Posts: 19,183

Re: Key Debates

Wow no more thoughts?

Third mission something to think of for the ispp would be to do trial runs refueling on the surface for hops around designated areas of mars for cargo landers using it like an outpost and crew lander for a second and forward mission use of the created methane /lox fuels using part of the fuel to go to the new site and being able to return to the original site to do the process all over again doing new science at each hop location before returning. That would be one way to set up for missions to land at the other outpost sites to continue to explore each if something is of interest at them.

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#7 2018-07-24 19:19:49

kbd512
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Re: Key Debates

SpaceNut,

Some kind of technology evaluation must be undertaken to determine how "ready" we are.  Right now, testing or basic development of key technologies is still lacking.  There's no coherent program to go anywhere and do anything and it's blatantly obvious.

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#8 2018-07-24 19:53:23

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,183

Re: Key Debates

Are we talking scalable demonstrator flights with key components or just a version of a lander that can bring to the surface also a scalable mass with the components to test out on mars

Are we talking a lander stuffed with a kilowatt power reactor, trial ISPP, moxie what are we really talking about to go. As far as I see its putting together the ship with the features required and landing them on mars for crew and cargo types.

We have many parts tried and tested with but not intergrated into a solution for use aside from a lander types for mars. .

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#9 2018-07-24 22:03:02

kbd512
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Re: Key Debates

SpaceNut,

We're talking scale flight demonstrators.  There aren't any.  We don't fly in space with untested technologies, period.  There are lots of things that need to fly before we can even think about sending people to Mars.  I would like to start with the technologies required to go there and come back, without a surface stay.  For example, a two year free return mission that demonstrates long duration habitation in space.

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#10 2018-07-25 10:24:19

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,027
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Re: Key Debates

My take on overall strategy is 3 phases,  rather similar to Spacenut.  We differ mostly in details (I have more of them). 

First (phase 1) is the initial landing (or the first few landings,  depending upon your mission architecture).  I call this “exploration”,  in the sense that you are primarily there to find out “what all is there, and where exactly it is”.  I mean that purpose quite literally,  just as written.  It is VERY far from the “flag-and-footprints with a tiny dab of science” that we did on the moon with Apollo. 

Visiting more than one site makes phase 2 success more probable.  Few mission architectures can do this,  though.  So the choice of one or many sites may have significant bearing on the mission architecture you actually select,  more so than most folks have considered so far.

A secondary objective would be to try out your resource utilization technologies,  but without having to depend upon them actually working!  Or being full scale size!  Depending upon your transportation design,  you may (or may not) have to make return propellant.  I would recommend against depending upon propellant manufacture in this phase,  unless you are absolutely forced to by your transportation design.

Second (phase 2) is where you prove-out,  adapt,  and improve your resource utilization technologies,  in an attempt to start a small permanently-occupied base that is at least partly self-sustaining.  If you have visited and experimented at multiple sites in phase 1,  then success doing this in phase 2 is far more likely.  This is precisely because you can pick the “best” site for the technologies you have in hand.  That IS important!  No two sites there will be alike, anymore than here.

The base is quite small,  and “permanent occupancy” is by crews that rotate in and out,  just not necessarily at every opposition.  There are low-gravity exposures and radiation exposures to consider,  as well as the psychological effects of years of confinement indoors.  Being outside in a bulky spacesuit is no better than being indoors,  psychologically speaking. 

One way to reduce the confinement effect is to “get on with war” and develop a real MCP suit,  so that going outdoors wearing it actually has significant beneficial effect psychologically. I still suggest doing the compression garment as vacuum-protective underwear that you can mix and match with outerwear appropriate to whatever task is at hand.  This is the absolute opposite of conventional spacesuit design practices today.

I would also suggest combining the elastic compression garment approach with the inflated capstan tensioner approach of the old partial pressure suits,  in order to solve the problem of rapid and easy donning and doffing the suit.

Phase 2 may go on for some time (several years or more,  even a few decades) before a permanent settlement of larger population is attempted.  It is the proving ground for “living off the land”,  as well as for coping with health effects. Do NOT attempt a settlement until you know that you really can “live off the land”,  and that you have acceptable health solutions.

Third (phase 3) is the larger-population permanent settlement.  This is where people come to stay permanently,  provided the feasibility of that is proven in phase 2’s base.  You must have long-term solutions for “living off the land”,  for health effects of low gravity and radiation,  and for the psychological confinement effect.  Lack of any one of these is a disqualifier to start the settlement.

It is not until after the settlement is established that social things like mode of government become appropriate.  These will develop naturally,  as will an economy relative to Earth.  I would hazard the guess that the initial exports from Mars would be intellectual property that can be transmitted electronically.  After that,  who knows?

This larger settlement will naturally grow into the colony that folks dream of.  It will happen pretty much in one of the same ways it happened here on Earth.  No one can predict which.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#11 2018-07-25 11:52:32

Oldfart1939
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Registered: 2016-11-26
Posts: 1,872

Re: Key Debates

My approach has always been very conservative optimism; in this manner, I support a stepwise and sustainable sequence of missions. But, Elon Musk and his BFR aside, we desperately need some stepwise pioneering style missions in the mode of Kit Carson and John Fremont in the American West. And do it with available COTS hardware, not sitting around debating about which is "better," electric propulsion or NTP. Neither of these is ready to perform NOW. Next mission window is 2020, and something needs be done then, or all the BFR/BFS broughhaha is revealed to be just more "Elon Dreams." On another thread, the one I started about the gaps in the BFR/BFS planning, I suggested using existing throw capabilities of the Falcon Heavy to resurrect the Red Mars missions, along with use of older, previously flown Falcon vessels suitably modified for this purpose. There is a LOT that needs done before a single astronaut/Marsonaut ever sets foot in a Mars bound spacecraft, so let's get the hell with the program!

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#12 2018-07-26 12:21:23

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,027
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Re: Key Debates

As near as I can tell,  Red Dragon was a modified crew Dragon.  They ripped out the seats and life support,  and installed cargo racks more like cargo Drago,  inside the pressure shell. 

They deleted the parachutes entirely. It was to use the same landing legs-through-the-heat shield that crew Dragon was originally supposed to have. 

I'm just guessing it had the cargo Dragon-type unpressurized service module,  with the solar wings. 

Crew Dragon carries more propellant than cargo Dragon,  as best I can tell.  1800 kg vs 1200 kg of MMH-NTO.
If you judiciously limit cargo weight loaded aboard to 1-2 tons,  then as best I can tell,  the delta-vee without the service module is about 1 km/s.  There's side and top hatches for moving stuff in and out,  just like crew and cargo Dragon.

That is just barely enough for a propulsive landing after aerobraking reentry direct from an interplanetary trajectory.  I'd prefer something in the 1-to-1.4 km/s range,  but Spacex knows its ship better than me. 

Current status is Red Dragon "gone",  and the legs and propulsive landing capability removed from crew Dragon at NASA's insistence. 

GW

Last edited by GW Johnson (2018-07-26 12:22:04)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#13 2018-07-27 02:03:46

louis
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From: UK
Registered: 2008-03-24
Posts: 5,854

Re: Key Debates

I've added a No.11.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#14 2018-07-27 17:18:36

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,183

Re: Key Debates

You could add in planetary transportation as we talked from light mass to pressurized to RV living from battery solar and nuclear powered as a number 12..

Amend: could include internal combustion, electric cart and or Bikes, running on compressed gasses something other than walking...

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#15 2018-07-27 23:06:44

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,026
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Re: Key Debates

This thread is a great idea, but at least some debates have been presented in a biased manner. For example, one I have been involved with...

louis wrote:

9. Artificial light agriculture v. natural light agriculture.

The idea of agriculture under natural light domes on Mars is a powerful one, and indeed was  one of the original motivations of Elon Musk - he wanted to see that developed.

But others point to the incredible amount of investment required to create and maintain such structures, certainly in the initial period of colonisation, when it might be more resource-effective to have multi-layered hydroponic agriculture in artificially lit enclosed spaces without windows.

(I argue for a phased switch from initial artificially lit agriculture to natural light farming over a few decades.)

I take exception to "incredible amount of investment required to create and maintain such structures ... more resource-effective to have multi-layered hydroponic". This statement blatantly ignores the massive investment in industry necessary to manufacture nutrient solutions required for hydroponics. Soil agriculture is simple, with few resources. Melting white sand to make glass is easy, simple, requires little investment. Artificial light sources and power supplies for them require significant resources. A fundamental of this debate is those pushing for hydroponics refuse to acknowledge the massive investment required to build and operate hydroponics. They refuse to accept that simple soil agriculture in a greenhouse requires far less investment. There are other arguments, but this is the one in your post.

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#16 2018-07-28 03:37:37

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,854

Re: Key Debates

I've made an amendment to reflect that.

RobertDyck wrote:

This thread is a great idea, but at least some debates have been presented in a biased manner. For example, one I have been involved with...

louis wrote:

9. Artificial light agriculture v. natural light agriculture.

The idea of agriculture under natural light domes on Mars is a powerful one, and indeed was  one of the original motivations of Elon Musk - he wanted to see that developed.

But others point to the incredible amount of investment required to create and maintain such structures, certainly in the initial period of colonisation, when it might be more resource-effective to have multi-layered hydroponic agriculture in artificially lit enclosed spaces without windows.

(I argue for a phased switch from initial artificially lit agriculture to natural light farming over a few decades.)

I take exception to "incredible amount of investment required to create and maintain such structures ... more resource-effective to have multi-layered hydroponic". This statement blatantly ignores the massive investment in industry necessary to manufacture nutrient solutions required for hydroponics. Soil agriculture is simple, with few resources. Melting white sand to make glass is easy, simple, requires little investment. Artificial light sources and power supplies for them require significant resources. A fundamental of this debate is those pushing for hydroponics refuse to acknowledge the massive investment required to build and operate hydroponics. They refuse to accept that simple soil agriculture in a greenhouse requires far less investment. There are other arguments, but this is the one in your post.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#17 2018-07-29 03:36:20

elderflower
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Registered: 2016-06-19
Posts: 1,260

Re: Key Debates

Finding white sand or other sources of reasonably pure silica, to give a glass with good translucence, is likely to be difficult on a planet where most everything comes with iron oxides attached. Failure to remove iron oxides will result in a dark glass. To rely on finding a suitable deposit is to further constrain the location of your permanent base.

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#18 2018-07-29 04:25:21

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,026
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Re: Key Debates

Silica deposits on Mars with features resembling hot spring biosignatures at El Tatio in Chile

Abstract
The Mars rover Spirit encountered outcrops and regolith composed of opaline silica (amorphous SiO2·nH2O) in an ancient volcanic hydrothermal setting in Gusev crater. An origin via either fumarole-related acid-sulfate leaching or precipitation from hot spring fluids was suggested previously. However, the potential significance of the characteristic nodular and mm-scale digitate opaline silica structures was not recognized. Here we report remarkably similar features within active hot spring/geyser discharge channels at El Tatio in northern Chile, where halite-encrusted silica yields infrared spectra that are the best match yet to spectra from Spirit. Furthermore, we show that the nodular and digitate silica structures at El Tatio that most closely resemble those on Mars include complex sedimentary structures produced by a combination of biotic and abiotic processes. Although fully abiotic processes are not ruled out for the Martian silica structures, they satisfy an a priori definition of potential biosignatures.

Sol721A_P2538_L257F-A721R1.jpg

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#19 2018-07-29 05:10:20

elderflower
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Registered: 2016-06-19
Posts: 1,260

Re: Key Debates

Looks like a possibility, but your selected location still has to have available water ice and a flattish and uncluttered (boulders etc.) area to land on, away from potentially unstable slopes like cliffs and large dunes. My point is that aa silica requirement is another constraint.

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#20 2018-07-29 07:59:05

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,183

Re: Key Debates

Silica falls under building materials and for what it will be used for in the design layout of what it is that we are building.
Ex. all glass greenhouse vs just a window to let light into an underground chamber.

Thanks for the post RobertDyck as I also remember an up turning of sulfur as well just below the rusting surface.

Which brings us back to the mining, exploration and science question of when and how we will go into trying to use insitu resources for mars.

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#21 2018-07-29 09:51:20

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,027
Website

Re: Key Debates

For those "first landing" explorations,  you only need a place flat and smooth enough not to crash,  and warm enough not to freeze to death at "reasonable" power expenditure.  For any size landing vehicle design,  the wider your landing leg span relative to your height is,  the more local roughness you can tolerate.  We're talking about shape differences under about a meter in a 5 to 10 meter distance here.

If you also intend to locally make your return propellants (presumed to be LCH4 and LOX,  but could be LH2 and LOX),  then you also need local massive ice deposits as a very crucial added requirement.  You do not want to be limited by the power,  time, and labor to process a thinly-spread resource: that would require more and heavier equipment to accomplish,  plus you might well miss your return opportunity.

The kind of resources needed to make local equivalents to glass,  concrete,  etc.,   are more appropriate to a semi-permanent or permanently-occuppied base or settlement.  That imposes much more stringent requirements on the site where you attempt such things. This is because surface travel across Mars will initially be by slow,  short-range surface rovers,  or by propellant-hungry "rocket hopper" travel.  No way around that,  not initially.

Here I must again emphasize that no two sites will be alike,  any more than here.  Resource availability will vary widely from site to site,  and the nature of that availability will be quite different for each different resource. 

Further,  remote sensing is not fully trustable enough to bet lives on.  There's simply too much ambiguity and inference in those results,  at this time in history.  You therefore must dig and drill deeply at each site to confirm exactly what is there and where exactly it is.  We just haven't been doing that with our unmanned landers and rovers. 

So,  does that not portend that multiple sites need to be explored and evaluated by crews on the surface for longer-term suitability?  Given the expense of interplanetary travel,  don't you want that answer out of your first trip there?  Just asking!!!!  It's a super-important question,  is it not?

I ask also because this question's answer utterly drives appropriate mission architecture and vehicle designs.  In all these debates,  I really haven't seen that aspect raised,  except by myself.  Yet it is crucially important for a program that could eventually successfully yield a viable permanent settlement.

Direct entry from the interplanetary trajectory is cheaper in a delta-vee sense (because of aerobraking in the Martian atmosphere),  but is very unadaptable to exploring multiple sites widely separated.  Orbital basing is more adaptable to exploring widely separated sites,  no one can really argue otherwise.  It just costs more delta-vee to do that. So, is exploring multiple sites important or not?  It sets what you actually attempt to do. 

There are supporting technology requirements for either approach, in terms of sending supplies and equipment ahead of the crew.  I'm not at all sure that either is yet "ready for prime time",  but orbital rendezvous might be closer to reality.  We did it at the moon,  but not from the approaching trajectory.

Landing of multiple vehicles at the same site will require an equivalent to GPS about Mars,  plus some sort of interactive beacon system to help the on board terminal guidance,  for landing exactly where you want.  All the direct landing scenarios require this,  and we do not yet have it. Even the orbital basing mission designs may need it,  if you land more than one vehicle at a site.

In terms of both long-term success and crew survival, these questions I raise are far more important than "simply" defining a mission architecture by min thrown mass or min program cost. (None of these are really simple.)

Just sayin'

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#22 2018-07-29 10:39:24

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,183

Re: Key Debates

So what makes a selectable site more or less a sustainable site than another?

Is it only a source of water?

What would be the next item if there is one that makes it so?

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#23 2018-07-29 10:54:14

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,026
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Re: Key Debates

Years ago I listed my requirements for a site, based strongly on NASA requirements. Members of this forum convinced me that the frozen pack ice meets all my requirements. That's in Elysium Planetia within driving distance of Gusev crater. A long drive, too far for Spirit or Curiosity, but a rover that drives the speed of an off-road vehicle can do it.

GW mentioned propellant.  Have to point out the difference of an exploration mission vs permanent settlement. Mars Direct showed us how to do exploration: bring LH2. An ice deposit must be proven and well characterized before committing human lives to it.

We're debating here. This thread is supposed to be a list of key debates. Could we move this to another thread?

Last edited by RobertDyck (2018-07-29 19:50:07)

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#24 2018-07-29 11:05:30

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,183

Re: Key Debates

I would suggest that each topic be created with the debate topic identifier with the poster making the topic with the article of debate that we are saying that we need. Repost as many Items from this one to start the discusion.
Once that is done we could each remove our own posts to reduce this back to the louis post that records each topic.

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#25 2018-07-29 11:17:31

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,027
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Re: Key Debates

To answer Spacenut in post 22:  it depends upon what resources you think you need while you are there.  Could be ice,  could be a lot more.

To answer RobertDyck in #23 and Spacenut in #24:  What I pointed out was that your mission architecture and vehicle designs are utterly driven by what you intend to accomplish while you are there.  This is further constrained by the expense and difficulty of even making just one trip. 

What that really means is that "what you intend to do while there" REALLY IS a fundamental debate item!  It's probably the prerequisite for all the others!

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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