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#251 2021-04-19 18:28:52

kbd512
Administrator
Registered: 2015-01-02
Posts: 4,893

Re: Settlement design

Calliban,

Reading that absolutely cracked me up! smile

1. Civilization is relative.  If you have the means to deliver all of those little floaters to the nearest waste water treatment plant, and to collect the trash, then I'd say things are pretty civilized.  Of all possible things, a hole in the ground left you traumatized for life?  Where did you expect it to go?  I mean, it has to go somewhere.

2. If you've ever frequented "non-ventilated pisseries", then you'll have an entirely new appreciation for "open air pisseries", so long as you're up-wind.  So long as there's no barf in the urinal, you're living the high life.

3.  My wife and her relatives are from Viet Nam, so we do get some interesting cuisine here and there.  I prefer to think of it as a dining adventure.  Unlike a box of chocolates, you truly never know what you're gonna get.

4. You actually turned down steak tartare?  Picky picky.  Only caviar and crumpets for the aristocracy?  My rule of thumb is that if it can be killed, it's on the menu.  And if you can't kill it, then you'd better make sure you're not on the menu!  In all seriousness, I draw the line at eating live animals, though, and I'm sure they appreciate that.

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#252 2021-04-19 20:45:54

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,249

Re: Settlement design

Calliban and kbd512-

I too, have used the hole on the floor crappers in Italy, at a mountain refuge back in 1963-64. This was at the Laverado Hut, near the Tre Cime di Laverado. About showers: I have done some winter mountaineering in Colorado, and extensive backpack trips in the California Sierra Nevada. The absolutely FIRST order of business upon return was always a long, hot shower. The backpack trips included some river crossings by using fords in some of the icy cold big rivers with hand ropes. I simply put on my swim trunks and sneakers, my wife into her bikini, and we got cooled off and (somewhat) cleansed.

A shower is really a tremendous morale booster. I recall coming into Ft.Carson barracks after a week in the field; there was a struggle to be first in the showers before the ancient barracks ran outta hot water.

Wet wipes just "don't cut it."

Last edited by Oldfart1939 (2021-04-19 20:47:33)

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#253 2021-04-20 07:34:46

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,983

Re: Settlement design

The discussion in recent days about the importance of providing sufficient water for expedition members will (most likely) be added by Noah and the team he is building to a requirements document for one or more plans.  I'll ask [Arctic Veteran] how that issue is handled at the Antarctic station where he spend a winter.

In the mean time, I've been thinking about the problem of decision storage needed for mission planners.

I decided to ask Google for help with the question, and it came back with an exhaustive list of references, most of which seem to involve NASA, but there would be thousands if not millions more if the search were allowed to continue. 

The Wiki format is a leading candidate for the purposes of forum members working on Settlement Design.  It has the distinct advantage of already being in place for a Mars Society outreach/education activity.  Whether it could be adapted for those who wish to plan missions to and in support of Mars is not clear.

Here is the list that Google came up with ...

Mission Planning Software - L3Harris Geospatial
Adwww.l3harrisgeospatial.com/mission-plan/software(303) 786-9900
Turn Geospatial Data/Imagery Into Timely, Accurate, & Actionable Intelligence. Contact Us! Custom & Off-The-Shelf Solutions Scientifically Proven For High-Confidence Decision Making. No Expereince Needed. Mission-Proven.

Object Tracking Webinar
GEOINT Training
Deep Learning Webinar
Product Stack

General Mission Analysis Tool (GMAT)
General Mission Analysis Tool (GMAT), Version R2020a  The General Mission Analysis Tool (GMAT) is the world's only enterprise, multi-mission, open source software system for space mission design, optimization, and navigation.
Mar 3, 2021

Space Mission Design Tools | NASA
www.nasa.gov › smallsat-institute › space-mission-design-tools
About Featured Snippets
Mission Planning & Operations | NASA
www.nasa.gov › centers › johnson › partnerships › otc › mission-planning-...
Aug 3, 2017 · With over 160 successful human space missions planned and executed, our teams ... We have extensive expertise that can be utilized in a wide spectrum of projects or ... of spaceflight hardware, software, facilities, plans and procedures. ... In addition, our comparisons of real time usage versus pre-flight ...

Automated Planning and Scheduling - NASA
www.nasa.gov › centers › ames › research › technology-onepagers › auto...
The Ames Planning and Scheduling Group has developed and demonstrated ... with experience delivering planning and scheduling software to flight missions. ... More complex problems often have many such constraints, and can benefit from ... This is especially true for missions that take place far from Earth, where novel ...

Orbital Trajectory Analyzer Takes Mission Planning ... - NASA Spinoff
spinoff.nasa.gov › Spinoff2016

Orbital Trajectory Analyzer Takes Mission Planning to New Heights ... NASA had been using software called Swing By for mission calculations, but when ... in 2009; the Magnetospheric Multiscale Mission in 2015; and it will be used for Origins ...
Space Mission Design for Everyone | openNASA
open.nasa.gov › blog › space-mission-design-for-everyone

Jul 28, 2011 · This is software that NASA can't examine, modify, or learn from. Therefore, this ... NASA uses a suite of tools for trajectory planning including:.
Software Catalog- operations - NASA's Software Catalog
software.nasa.gov › operations
63 results · This implementation of the Constellation Program's C3I software has provided an ... The Mission Display (MDX) System can be used to visualize a wide variety of ... visualization with sophisticated planning and simulation capabilities.

9.0 Flight Software | NASA
www.nasa.gov › smallsat-institute › sst-soa-2020 › flight-software
Nov 27, 2020 · The more software has to do, the bigger the task and cost. ... It is used in space flight, medical, networking and many more embedded devices. ... Create a plan*, schedule, and budget for software: a plan is needed to fully ...
[PDF] NASA Software Catalog 2019-20 - NASA's Software Catalog
software.nasa.gov › NASA_Software_Catalog_2019-20
requester can download the software directly; it is not necessary to use the Request. Software button ... Flexible Docking Tool for Real-Time Planning Missions.

Planning & Scheduling - Intelligent Systems Division - NASA
ti.arc.nasa.gov › tech › asr › groups › planning-and-scheduling
Additionally, the group has extensive experience delivering planning and scheduling software to NASA missions involving ground, flight, and surface operations, ...

mission planning software: Topics by Science.gov
www.science.gov › topicpages › mission+planning+software
The STAMPS software is used for mission planning and analysis within ... NASA's Mars Science Laboratory (MSL) rover mission is planning to make use of ... the requirements for the Space Mission Planning and the benefits which can be ...

(th)

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#254 2021-04-20 07:43:44

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,983

Re: Settlement design

The need that **I** see for progress in planning for missions in support of Settlement design is the ability to fix a decision.

There will ** always ** be better ways of doing things, but human progress depends upon the ability to make a decision and build from there.

Occasionally it becomes painfully obvious that a decision made at some point has downstream consequences that mean the entire effort has to be stopped and work restarted from the point of failure.  However, the accumulation of wisdom/judgement by humans allows for ** some ** organizations to avoid rework.

That said, the number of people to be included in a mission to Mars is an example of one that MUST precede a cascade of downstream decisions.

Another such decision is about the quality of life the mission planners are willing to provide.  The best bet ( it seems to me ) is to error on the side of generosity, and accept the consequences of increased mass for the expedition.

(th)

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#255 2021-04-20 07:58:35

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,682
Website

Re: Settlement design

Re Louis post 229 above "steel gets brittle in the cold":  not all steels are the same.  Mild carbon steel gets brittle in the cold.  Sometimes just below the freezing point of water.  Depends upon the abuse it is exposed to.  Spacex's Starship is constructed of 304L stainless steel,  which is the most-preferred alloy for cryogenic tanks on Earth,  precisely because it is still somewhat ductile even at cryogenic temperatures.  It is also resistant to high temperatures,  if you don't demand too much of it,  and you don't care that it will revert to its soft,  annealed,  low-strength characteristics.  There are other alloy steels that will go hotter with higher strength,  but they get brittle cold.  Spacex needed both hot and cold properties.  The nonmagnetic 300 series,  specifically 304L,  was the right choice.

Re Calliban 193 "role of Young's modulus in concrete (or any other composite)":  you have a reinforcing rod or fiber embedded in a matrix,  with lots of shear strength along the boundary between the two.  Thus when you load the part, both must deform by the same amount.  That deformation,  normalized by a part dimension,  is called strain.  The stress corresponding to that strain is that strain multiplied by Young's modulus,  and it must be less than the failure value for that material,  something that depends how it is loaded.  The forces carried by that composite part's matrix and reinforcement are their stresses (which are quite different) multiplied by their cross-sectional areas normal to the force direction (also quite different). 

In concrete that gets loaded in tension (either directly,  or via bending),  you have to have enough of the higher-modulus steel rebar to carry essentially all of the tension force.  Otherwise the concrete will crack and the rebar will (eventually) corrode away.  Steel has about 3 times the Young's modulus as the concrete matrix.  Anything with a lower Young's modulus used as reinforcement will require a substantially higher proportion of reinforcement cross section.  Plus,  the elongation-at-failure of the reinforcement must be higher than the elongation-at-failure of the matrix,  or the combination cannot work correctly as a composite,,  because of a very undesirable failure mode.  The elongation-at-failure of mild steel is 6-8%.  That of concrete in tension is essentially zero.

So there are two critical requirements for your reinforcement selection:  (1) Young's modulus substantially higher to reduce reinforcement proportion to practical values,  and (2) elongation-at-failure substantially higher so that at failure cracks first appear in the matrix,  not the reinforcement. 

In addition,  the shear strength of the bond between the two needs to be very high.

GW

Last edited by GW Johnson (2021-04-20 08:18:01)


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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#256 2021-04-20 08:46:00

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,983

Re: Settlement design

For GW Johnson re #255

SearchTerm:Analysis of design of steel reinforced concrete (extended to general cases) see #255
SearchTerm:Failure analysis for reinforced concrete
SearchTerm:Elongation requirement for tension element of composite structure
SearchTerm:Sheer strength for elements of composite architectural structure.

(th)

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#257 2021-04-20 08:49:25

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,298

Re: Settlement design

Thanks GW.  Considerations like this certainly limit design options.

The more I weigh the pros and cons, the more sensible it begins to look building most things underground on Mars.  On Earth, an underground house has 20-30% higher capital cost, though negligible heating costs.  But on Mars, everything built on the surface requires the use of space suits and pressurised vehicles until it is pressure tight.  The buildings and equipment must tolerate low temperatures and high temperature ranges.  Structures like domes, would not protect their inhabitants from cosmic radiation.  Whilst this won't be imminently catastrophic to human health, it is a hazard that should be avoided.  Surface structures must be insulated and heated.  A dome would lose a lot of heat over the course of a Martian night. 

I think that Elon Musk probably realises this and this explains his interest in shipping boring machines.  There are some things that cannot easily be done underground, like growing food.  We still need sunlight for that, unless electric power is very cheap.  So heated greenhouses are going to be a necessity.  For most other infrastructure, it makes more sense going underground.  One additional advantage to going underground, is that most structural elements can be designed with compressive forces in mind.

Last edited by Calliban (2021-04-20 08:52:07)


Interested in space science, engineering and technology.

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#258 2021-04-20 08:53:16

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,983

Re: Settlement design

Requirement for Encouragement of Failure

In order to attain good judgement, a candidate for leadership must subject (self) to the certainty of failure

The Silicon Valley rule-of-thumb is that only 1 venture out of 10 funded will result in success, so that success must out weigh the losses for 9.

I'm not sure if that rule-of-thumb extends to actual human beings who lead ventures that fail, but I suspect there must be ** some ** such number.

My rule-of-thumb (based on nothing at all at the moment) is that a leader must fail repeatedly in order to attain good judgement.

It is possible to absorb wise advice (or ignore it) but in the end, it is the judgement of the leader that must be tested in contest with the Universe.

The decision to go with an 8 person crew for an expedition is an example of one that must be put to the test.

There have been human expeditions of various sizes for hundreds of thousands of years.

The most common is likely to be the individual who explores the terrain within walking distance.

Expeditions have reached the hundreds in the flourishing period of exploration starting in the 1400's and extending onward.

Oldfart1939 has recommended the number 17.

There ** should ** be historical data to help a leader to evaluate the optimum size for a given mission.

(th)

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#259 2021-04-20 09:41:56

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,249

Re: Settlement design

Perhaps an explanation of my number of 17 is needed here.

I have adopted a concept from various military organizations, in that the minimum effective survival and operational group is 3, a "triad." We're not doing military activities on Mars or even the Moon, but it makes sense if this is the size of a group "going exploring." There is enough manpower (womanpower?) available to effectively rescue an injured person, and that is a distinct possibility when walking on unknown terrain.
The military concept was this: in a group of 3, 1 was alert and keeping watch; a second was doing the meal preparations and dealing with equipment maintenance; the third was sleeping.

If we are doing any sort of heavy construction or moving equipment from point A to point B, the need for an ability to rescue an injured/ill person is paramount.

For an expedition lasting over 2 years, we'll need 3 in the medical professions: doctor, dentist, and a nurse.

We'll certainly do cross training with other members of the crew as backup for these professions, but we cannot be too optimistic about nobody getting hurt or having an heart attack or appendicitis.

A triad of geologists to do the bulk of scientific explorations, working mostly outside the hab.

Construction workers, and equipment operators; 2 triads.

Scientists doing laboratory analysis and plant growth experiments; another triad.

Leadership and planning: just a mission leader and an assistant (backup) mission leader and communications specialist.

We're going to Mars to explore and do science, so we let the scientists and geologists do their jobs without overloading them with secondary tasks. But everybody pitches in with hab cleanliness and cooking and cooking cleanup.

The construction of a permanent base will be left to the construction and equipment operators as will be maintenance of the rovers.

But there will be 5 triads, and 2 persons in leadership roles. They could be another doctor or a highly trained medic and/or an engineer.

This adds up to 17.

Last edited by Oldfart1939 (2021-04-20 09:49:13)

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#260 2021-04-20 10:38:52

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,983

Re: Settlement design

For Oldfart1939 re #259

SearchTerm:triad Groups of triads of specializations to make up optimum recommended exploration team Oldfart1939 Post 259
SearchTerm:group size for an expedition to Mars analysis of
SearchTerm:expedition size for Mars

(th)

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#261 2021-04-20 10:42:33

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,983

Re: Settlement design

Considering the size of the archive of this forum, I am confident this is NOT a new idea, but it seems time to re-introduce it ...

Supplies for an expedition NEED NOT be landed!

Backup supplies of drinking water and other critical items can (and I believe ** should ** be) stashed in orbit.

There's been discussion recently in Orbital Mechanics and elsewhere of the advantages of high elliptical orbits.

Such orbits seem (to me ahead of correction) to be suitable for caches of supplies that are positioned ahead of an expedition for emergency use if needed.

Such supplies can certainly be used at some point if they are not needed for emergency backup, so the investment is not wasted.

(th)

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#262 2021-04-20 13:47:57

Noah
Member
From: Zurich (Switzerland)
Registered: 2020-07-28
Posts: 38

Re: Settlement design

Thomas wrote:

I do have one question about your preference for 8 people in a mission ... You no doubt saw the recommendation of 17 by Oldfart1939.

Yes, I saw his recommendation and he had some important points. Especially in regards to the workload for the settlers.

I will post a rationale for my number by the end of this week.

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#263 2021-04-20 13:50:27

Noah
Member
From: Zurich (Switzerland)
Registered: 2020-07-28
Posts: 38

Re: Settlement design

SpaceNut  wrote:

Noah's reminder;
The crew size is determined when the amount of mass from each incremental person slows the amount of change in ship dry mass to get man leaving Earth to go to mars as to the only thing changing are the life support quantities.
Which effects recycling numbers.
What goes into the selection process
https://www.mars-one.com/mission/mars-one-astronauts
Some of the risk
https://ieeexplore.ieee.org/document/6836241
Nasa Gateway mission to Phobos is a prover that we can survive
https://www.space.com/29562-nasa-manned … hobos.html
The Cost and Equivalent System Mass of Space Crew Time
https://spacecraft.ssl.umd.edu/design_l … e_cost.pdf
This is the one that talks to all of how the rockets are designed all the way to its surface and back to earth for the crews survival which means it covers the ballistic entry to mars
Part 1 & 2
https://space.nss.org/wp-content/upload … o-Mars.pdf

Thank you for the information. I will definitely consider them.

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#264 2021-04-20 17:25:42

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,087

Re: Settlement design

Well as I posted above I see this really as a Phase 2 of urban development on Mars. Personally I would favour terraced hillside boring for residential habs, and not too far into the hill, so we remain connected to the daily cycle of light. But true tunnelling may be fine for applications like rover garaging and maintenance, (artifical light) farm habs and warehousing.

Calliban wrote:

Thanks GW.  Considerations like this certainly limit design options.

The more I weigh the pros and cons, the more sensible it begins to look building most things underground on Mars.  On Earth, an underground house has 20-30% higher capital cost, though negligible heating costs.  But on Mars, everything built on the surface requires the use of space suits and pressurised vehicles until it is pressure tight.  The buildings and equipment must tolerate low temperatures and high temperature ranges.  Structures like domes, would not protect their inhabitants from cosmic radiation.  Whilst this won't be imminently catastrophic to human health, it is a hazard that should be avoided.  Surface structures must be insulated and heated.  A dome would lose a lot of heat over the course of a Martian night. 

I think that Elon Musk probably realises this and this explains his interest in shipping boring machines.  There are some things that cannot easily be done underground, like growing food.  We still need sunlight for that, unless electric power is very cheap.  So heated greenhouses are going to be a necessity.  For most other infrastructure, it makes more sense going underground.  One additional advantage to going underground, is that most structural elements can be designed with compressive forces in mind.


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

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#265 2021-04-20 18:27:35

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,826

Re: Settlement design

Earth under ground builds have the issues of water in springs, ground water tables to start with and rain storms that never seem to stop for why its harder here than it will be on mars.....

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#266 2021-04-20 22:27:46

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,249

Re: Settlement design

th-

Re: post #261.

This isn't the first time I've mentioned the triad concept; you can go back 3-4 years to find my original posting.

Noah mentions the work load aspect of things and this is one of the reasons a larger crew is valuable. It's also better for the mission psychology to have a larger group for some more normal social interactions. I personally think that a 4 man crew would be a disaster, and an 8 man crew only marginally better. I toyed with the idea of 11 as something of a compromise, but the workload will be enormous. There will need to be some TIME OFF from duties, to simply go exploring and appreciate where they are. Mission planners tend to overlook that sort of detail, and have the daily workload scheduled from dawn to dusk. I also insist on an odd number within this group, if something comes down to voting--there won't be ties that will cause problems.

I'm really glad that Elon has planned on a large scale, which makes a larger mission possible--with adequate food supplies for an aborted return if something goes wrong at the Hohmann Transfer window. Remember Murphy's Law; then remember that Murphy was an optimist.

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#267 2021-04-21 06:26:18

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,983

Re: Settlement design

For Oldfart1939 re #266 and your earlier work

Thanks for reminding me (and hopefully other forum readers) of the wealth of previously stored knowledge/insight/practical advice available in the archive,

As you have no doubt noted, I've been attempting to address the issue of the nature of the design of the forum, which allows contributions to flow under the bridge into oblivion.   This aspect of the forum structure has an advantage that i do not discount ... it is constantly in need of refreshing, and often, as members restate their earlier work for new arrivals (or lately, for old members who cannot remember), they improve upon the earlier version.

This morning, ahead of the first log in of the day, I've been thinking about a structure that might work within the existing environment, to build up a tutorial on the nature of heat at the quantum level.  I'm inspired by memories of the presence of JoshNH4H, who often suggested ideas in the realm of physics that were (and remain) thought provoking.  I'll ** never ** forget his lesson on the nature of electron shells, for example, as he led a discussion on how energy might be stored by (somehow) bottling the potential energy of galactic protons, which arrive in our vicinity with no electrons at all.

Now to the point you are renewing ...

I am persuaded by your argument, but am not the owner/manager/guiding spirit of this topic.  Noah is still at a point where he could change his mind, but it is important for ** someone ** somewhere ** to make a decision about crew size in order for this topic to progress in an orderly manner toward whatever success is going to look like.

At the moment, unless Noah instructs us otherwise, he is committed to the number 8 for the crew of an expedition.

Your presentation of the advantages of 17 seems worth continuing as an alternative waiting in the wings while the choice of 8 is given a thorough review.

Please consider assembling links to your earlier work and editing them into post 266.

Something we can all keep in mind is that our earlier posts remain secure (thanks to the generosity of good management of the Mars Society), so we can edit them to improve them ... they do not need to remain static.  The My Hacienda PlotMaster is an example of a work-in-progress.

Now, back to the matter at hand ... human history ** should ** include a great number of examples of expeditions of all sizes.

The number 8 may turn out to have been spectacularly unsuccessful, or successful, or some mixture.  At this point ** I ** have no idea, but what I CAN do is to invite present forum members to do some research in this very specific focus ... compare and contrast expeditions with 8 members and with 17.

If there is a forum member who has not yet posted a message, please consider doing so.  A review of membership records is about to begin, and (if SpaceNut approves) records with no posts and no logins since registration will be converted for use by new members we hope to recruit over time.

The first phase of this ID review will be limited to already banned User Id's, so there is plenty of time.

I bring this up because there are hundreds of you who went to the trouble of securing a membership in this forum but have done nothing with it.

There is a ** lot ** of work to be done to help Noah and his team to develop plans to settle Mars, or to support Mars settlers from the safety and security of Earth, which is what the vast majority of Mars settlement participants are going to be doing.

Edit: To start things out ... Magellan started out from Spain with five ships and (about) 300 men. One ship and 18 men returned.

The Lewis and Clark expedition started out with some number of personnel.  All I'm sure of is that the number was greater than 17. My recollection is that only on member died, and that was of natural causes, untreatable at the time but easily corrected today.

The English attempt to explore the Northwest passage had at least two ships and several hundred personnel.  They had the distinct disadvantage of unproven and ultimately deadly canning procedures that resulted in lead poisoning.  Such a mistake is unlikely for a Mars expedition, but there may be something fundamental like that waiting in the wings to wipe out unwary humans.

(th)

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#268 2021-04-21 10:23:19

Noah
Member
From: Zurich (Switzerland)
Registered: 2020-07-28
Posts: 38

Re: Settlement design

Thomas re #267
I am constantly looking for new arguments concerning crew size. As Thomas said, if someone has new arguments, I will adopt them.

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#269 2021-04-21 11:23:19

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,249

Re: Settlement design

Thomas-

My Triad concept began in 2016, I believe. But at the time, I initially was looking at a 7 person crew because of a perceived  transportation bottleneck or limits. I subsequently expanded to 11 and most recently to 17 based on the Starship concept. Taking TOO MANY people on an exploratory/experimental mission is fraught with hazards, and I'm leaning towards using the mass saved by a smaller crew to bring extra food and equipment required for building habitats and survival. I am of the opinion that more than 17 isn't a very good idea, and that 11 could also work, but with lower productivity overall.

For similar reasons to mine, the US Army infantry squad is 11; two 5 man fire teams and a squad leader.

I'm of the opinion that the rover should be built to accommodate 7 persons; 2 triads and a leader, one of which will be the driver. The crew remaining at the hab/base camp should avoid radiation exposure until their turn to venture forth on some exploration and outside work.

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#270 2021-04-21 19:02:48

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,826

Re: Settlement design

tahanson43206 wrote:

Considering the size of the archive of this forum, I am confident this is NOT a new idea, but it seems time to re-introduce it ...

Supplies for an expedition NEED NOT be landed!

Backup supplies of drinking water and other critical items can (and I believe ** should ** be) stashed in orbit.

There's been discussion recently in Orbital Mechanics and elsewhere of the advantages of high elliptical orbits.

Such orbits seem (to me ahead of correction) to be suitable for caches of supplies that are positioned ahead of an expedition for emergency use if needed.

Such supplies can certainly be used at some point if they are not needed for emergency backup, so the investment is not wasted.

(th)


No need to have the cargo stay in orbit unless you are planning to send the cargo to another location on the planet at a later time than for when it gets delivered to mars orbit. Station keep fuel is not really being planned on for the cargo ships to stay there for any period of time as would be the case for the ISS or satelites.

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#271 2021-04-21 20:38:06

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,983

Re: Settlement design

For SpaceNut re #270

I read your post here several times, and I still get the same result.

It ** sounds ** as though your concept is to land all your supplies to get home, instead of leaving them safely in orbit, out of harm's way.

(th)

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#272 2021-04-21 23:29:46

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,249

Re: Settlement design

It actually makes a lot more sense to land the supplies; the environment on Mars is cold and very dry, so dried foods and rations should be fine almost indefinitely. If the supplies are brought down to the surface, they will be put to a good use.

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#273 2021-04-21 23:35:09

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,892
Website

Re: Settlement design

tahanson43206 & Oldfart1939,
You guys appear to be talking about different things. Landing anything needed for return to Earth is a waste of fuel. Better to leave it parked in Earth orbit. Remember, supplies for return to Earth cannot be used on Mars. At all. If you use them, then you don't have what it takes to get home.

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#274 2021-04-21 23:59:25

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,892
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Re: Settlement design

This made me think of mission architecture again. In post #142 on page 6, I described my idea and how to fit that in Starship. It requires 2 cargo Starships + 2 tanker Starships + 1 Falcon 9. Compare that to Elon's plan for Mars. Each launch requires 1 Starship, plus up to 6 tanker Starships. And Elon's plan is to pre-position several cargo Starships before crew arrive. Whether cargo or crew, each requires 6 tanker Starships. If 8 cargo Starships are sent, that requires 8 cargo, 1 crew, (8+1)*6=54 tankers, for a grand total of 63 Starship launches.

I remind anyone reading this, that my smaller mission plan means a dedicated habitat for Earth return is left in Mars orbit, loaded with supplies for the return trip, and a Dragon capsule.

Cost (number of launches) is only one concern. Another is safety. I suspect one reason Elon wants to pre-position supplies is to practice landing Starship on Mars. I could post video of Starship tests to date. His approach means rapid innovation, but it also means first try does not survive. Anything with crew must survive first try. I argue a deployable heat shield (ADEPT or HIAD) with parachute is far safer. Yes, final touch-down on Mars must be propulsive. But touch-down with a low centre of gravity and legs with wide stance, shock absorbers, large feet (pads), and landing rockets that only operate from 200 mph to landing, is a lot safer. (Perseverance rover separated from back shell with parachute at that speed.)

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#275 2021-04-22 00:54:52

kbd512
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Registered: 2015-01-02
Posts: 4,893

Re: Settlement design

I just thought of a good name for the first crewed Starship that lands on Mars.  That first ship shall be christened Audacity.  Her sister ship that carries the other four astronauts shall be christened Alacrity.  The first true colonization class ship, a ship of the line, a vessel that Starship clearly isn't, shall be christened Enterprise, for that is what she truly represents.

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