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#76 2021-05-22 09:22:44

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For SpaceNut re Oldfart1939's request for feedback on the Primary topic ...

Can I interest you in tackling the request?  I'm willing to walk through the elements of his concept with you, if you have the time.

We have requested feedback multiple times, and no one has responded to date. 

If you are interested in this, let's discuss how we are going to proceed before we jump into it.

Edit#1: We sorely miss GW Johnson at this time.  Hopefully he'll acquire brand, spanking new hardware soon, and return to the fray.

(th)

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#77 2021-05-22 10:32:04

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 24,438

Re: Companion fo Mars Expedition Number One; 17 crew members

Mission architecture still needs some defining:
Some things that go beyond the solar nuclear battle is how many starships are to be used from launch to refuel, the leg of the journey to mars with or without AG, leaving anything in orbit for the return home, how many are going to land on mars surface with cargo and crewed, is there a small return capsule rocket landed that is not a starship for use of return to orbit to mate up with a waiting starship to go home.

Science and construction activity:
Defining has started with expansion and setup of critical power, water, air and food supplementing. The science of exploration has started with defining surroundings with a variety of interests from geological, life determination past or present and water hydrology for lessening energy requirements.

Payload cargo delivered:
There is some mention of vehicles to be used in exploration science roles, construction with heavy or light to be utilized for the tasks assigned, specialized equipment for water searching, there is power sources or both nuclear and some solar battery to be made use of, fuel creation processing equipment partially defined for desired return to earth.

Returning cargo:
This defines some of the science goals to bring samples back to earth and the question here is how much and what in particular to bring back. Natural water samples would also be included in the rock mineral selection as well.

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#78 2021-05-22 10:51:53

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For SpaceNut re #77

Thank you very much for taking up the challenge of helping Oldfart1939 with whatever he is trying to do here.

If the intention of the activity is to create an article for publication, then perhaps looking at the big picture, as you have done in this post, makes sense.

On the other hand, from my perspective, it is totally unnecessary for Oldfart1939 to worry about tasks that can be delegated to others.

From my perspective, transportation of the expedition crew and equipment to Mars is the responsibility of someone else.

It makes no sense (again, from my perspective) for Oldfartf1939 to spend one moment thinking about that.

The expertise Oldfart1939 brings to bear on this problem is that of a scientist with experience in running at least one business, and (if memory serves) more than one.

I would like to see the focus of this work entirely on choosing the personnel, and defining the tasks they will carry out.  From those two basic elements, the equipment needed and the supplies to be procured will flow.

Oldfart1939 has asked for specific feedback on specific text he has written.

Would you be willing to see if we (at the moment we are the only participants) can examine the specific text in detail, word by word, to provide feedback?

(th)

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#79 2021-05-22 11:02:06

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 24,438

Re: Companion fo Mars Expedition Number One; 17 crew members

power requirement and precursor mission to settle the nuclear vs solar argument

The first landed mission on mars would be automated no crew and its got to be able to return or we risk man if it can not....

Louis the watt hours are even higher as its 700w x 25 hrs x 456 day = 7,980,000 watt hours....

of which 7,980,000 / 1,750,000 = 4.56 hr of sun light at full strength hitting the field of panels being stored and used every hour at a constant rate of 17,500 watts hrs daily meaning the array is storing 3,192 watts during the charging of the battery process to meet the need for power minimum.

42000 m^2 is approximate 205 m x 205 m

The Krusty unit can handle the full power needs for the fuel processing plant if we have feed stock hydrogen....

You have no free standing water, or hydrogen to make into fuel at a ration of 1Kg H2 and mars co2 to come up with 18Kg of fuel.

Nuclear SP-100 to provide power for a reaction that makes a source of 5.8 tonne of H2 brought from earth to make a 3.6:6 mix ration of methane to oxygen for a grant total of 106 tonne of fuel over a 26 month period before you can send humans for the mars direct and that ship mass was not even a third of starships...

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#80 2021-05-22 11:45:13

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For SpaceNut re #79

Thank you for helping me to understand why we (forum members) have not yet been able to focus on Oldfart1939's request.

It would appear we are still trying to do Oldfart1939's work for him.

The mission Oldfart1939 has defined is a **manned** mission with 17 people!  It is NOT an automated mission.

What I'd like to do (or at least ** try ** to do) is to enlist forum members to give Oldfart1939 specific feedback on specific words he put into the Primary topic.

Would you be interested in working with me to see if we can show what that would look like?

It seems clear (to this point) that no one currently registered in the forum understands what was requested, or how to go about helping.

We can show the way.

(th)

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#81 2021-05-22 16:47:34

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 24,438

Re: Companion fo Mars Expedition Number One; 17 crew members

I made a bit of an error wih the power level as..... its only that level for 6 months of summer then it slowly will decrease through fall towards winter in which you will drop even more before coming back up in spring.... of which each is a 6 month spell

Spring and fall will have the power drop to under the 430 w level and by winter it will be down to 280 watts

so the above calulations will not yield the watt Hours we need as the time for charge gets shorter as well during each of the periods of the seasons.

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#82 2021-05-23 07:06:45

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For SpaceNut re Mars Expedition 17 crew members

I went back and re-read Post #1 ... Your vision of the topic as a kind of Wiki is interesting.

My vision for Oldfart1939's work is that it would develop into an article that could be published in a mainstream periodical, at the level of Popular Mechanics or Analog, or (stretching) Scientific American or Discovery or (really stretching) National Geographic.

Your vision of a Wiki format is compatible with all of those.

In the Companion topic, in Post #65

(th)-
I was hoping for some commentary and input on my latest post of the 17 astronaut crew thread.

The time of Post #65 was 2021-05-18 18:53:03

Working backward, the latest post in the primary topic was #10 at 2021-05-17 12:52:33

Some self-criticism and evaluation: everyone on the mission will be physically fit and able to pitch in with construction at least 4 hours of their on-duty shifts. As the base takes shape and construction of the essential habitat construction winds down, the scientists can get to work doing science, and the geologists doing the bulk of exploration and looking for water and other useful minerals for base use.
After the initial construction phase requires less input from the construction triads, they can be utilized in the greenhouse and food growing business. There will be a LOT of work in setting up the base, and why I'm self-critical is that the workers will be initially overloaded and scientists, geologists, and medical staff will be somewhat underutilized.

Let's think about this specific text, in the context of wanting to assist Oldfart1939 as best we can, as he takes on this enormous task.

Let's think about each sentence, and comment specifically on that.

1)Some self-criticism and evaluation: everyone on the mission will be physically fit and able to pitch in with construction at least 4 hours of their on-duty shifts.

2)As the base takes shape and construction of the essential habitat construction winds down, the scientists can get to work doing science, and the geologists doing the bulk of exploration and looking for water and other useful minerals for base use.


3)After the initial construction phase requires less input from the construction triads, they can be utilized in the greenhouse and food growing business.

4)There will be a LOT of work in setting up the base, and why I'm self-critical is that the workers will be initially overloaded and scientists, geologists, and medical staff will be somewhat underutilized.

(th)

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#83 2021-05-23 07:47:04

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For Oldfart1939 ... Noting your instructions in Post #75 ....

I have a request for you ... do you retain ownership of Post #1 of your topic?

If you do, please visit the topic and edit it until it suits you.

Then please report the update here.

As you may have noted, I am working on the challenge of obtaining useful feedback.

It is possible that some members of the forum have never submitted a paper for publication, and younger ones may not yet have submitted a paper for grading.

The needs of an author may not be known to some members of the forum.

I am hoping you have the patience to bring along those among the active membership who might be interested in helping.

The outreach effort is moving slowly at this point.  I suspect that all the "guests" showing up in the daily activity report are spammer software, probing the Internet for web sites that might allow them in to drop off advertising.

(th)

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#84 2021-05-23 07:56:54

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,097

Re: Companion fo Mars Expedition Number One; 17 crew members

We're talking about Mission One, right? I don't see a large work requirement for "construction".

Surely you would use Bigelow-style inflatables. These might need to be towed to the base location (some way from the nascent spaceport). The inflatable habs need integrated airlocks big enought to accommodate a small human rover, similar to NASA's Mars rover).
Personally I would favour double airlocks - a large external big enough to house the rover. You'd probably take along a couple of rovers. At about a couple of tons each that won't take up much mass.

For Mission One I think you'd probably have a small inflatable hab to house people while the main buildings are put up.

I can't see why all the habs wouldn't be inflatables. You might have two (or more) residential habs, an experimental farm hab producing salad crops. Maybe an electrical connector hab, to make monitoring and maintenance easier? Maybe a science hab for collecting and examining specimens. Lastly, maybe an industrial hab for 3D printers, experimental furnace and experimental construction techniques.

How the propellant production facility created is probably the main question.

Furnishings for the hab would be pretty much auto-assembly I think.

tahanson43206 wrote:

For SpaceNut re Mars Expedition 17 crew members

I went back and re-read Post #1 ... Your vision of the topic as a kind of Wiki is interesting.

My vision for Oldfart1939's work is that it would develop into an article that could be published in a mainstream periodical, at the level of Popular Mechanics or Analog, or (stretching) Scientific American or Discovery or (really stretching) National Geographic.

Your vision of a Wiki format is compatible with all of those.

In the Companion topic, in Post #65

(th)-
I was hoping for some commentary and input on my latest post of the 17 astronaut crew thread.

The time of Post #65 was 2021-05-18 18:53:03

Working backward, the latest post in the primary topic was #10 at 2021-05-17 12:52:33

Some self-criticism and evaluation: everyone on the mission will be physically fit and able to pitch in with construction at least 4 hours of their on-duty shifts. As the base takes shape and construction of the essential habitat construction winds down, the scientists can get to work doing science, and the geologists doing the bulk of exploration and looking for water and other useful minerals for base use.
After the initial construction phase requires less input from the construction triads, they can be utilized in the greenhouse and food growing business. There will be a LOT of work in setting up the base, and why I'm self-critical is that the workers will be initially overloaded and scientists, geologists, and medical staff will be somewhat underutilized.

Let's think about this specific text, in the context of wanting to assist Oldfart1939 as best we can, as he takes on this enormous task.

Let's think about each sentence, and comment specifically on that.

1)Some self-criticism and evaluation: everyone on the mission will be physically fit and able to pitch in with construction at least 4 hours of their on-duty shifts.

2)As the base takes shape and construction of the essential habitat construction winds down, the scientists can get to work doing science, and the geologists doing the bulk of exploration and looking for water and other useful minerals for base use.


3)After the initial construction phase requires less input from the construction triads, they can be utilized in the greenhouse and food growing business.

4)There will be a LOT of work in setting up the base, and why I'm self-critical is that the workers will be initially overloaded and scientists, geologists, and medical staff will be somewhat underutilized.

(th)


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

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#85 2021-05-23 08:03:35

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,097

Re: Companion fo Mars Expedition Number One; 17 crew members

OF might find this useful for comparison. I haven't been through it yet...

https://digitalcommons.lmu.edu/cgi/view … ntext=ulra


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

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#86 2021-05-23 12:43:12

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For OF re http://newmars.com/forums/viewtopic.php … 82#p180282

Bravo!  Nice addition to the Primary topic!

Thanks for keeping the momentum going, while we (in the forum) try to sort out how we can help.

(th)

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#87 2021-05-23 13:25:07

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,270

Re: Companion fo Mars Expedition Number One; 17 crew members

We all know that survival is THE primary goal for the crew; adequate shelter is prime importance to keep them protected from the hostile environment. My goal was another example of using the KISS principle. I'll be expanding and expounding later.

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#88 2021-05-23 14:31:30

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 24,438

Re: Companion fo Mars Expedition Number One; 17 crew members

Well if going with inflatables then we will need to recycle the metal shell from an unused cargo ship to place them under so as to allow for regolith soils of mars to be piled on top of these structures to gain radiation protection.

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#89 2021-05-23 15:07:36

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For SpaceNut re #88

The forum archive contains some number of references to and discussions of brick arches ...

Here is the most recent: http://newmars.com/forums/viewtopic.php … 48#p178848

I think that an arch made of native material by robot expeditions before humans show up would be a useful preparation.

(th)

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#90 2021-05-23 15:31:36

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 24,438

Re: Companion fo Mars Expedition Number One; 17 crew members

The arch would need to not bare weight to the outside of the inflatable so a gap would be present between the bricks and the round shape of the units. That would lead to rubbing on the rough surfaces of the brick or rock depending on what its setting on. The wear and tear of rubbing would not be something we would want.

It also does take quite a bit of time to fabricate the brick as you must select the correct regolith to make them with even if you send the machinery to do so.

Cutting the shell of the starship cargo off should be possible and the underlying insolation would pad the inside for the inflatable to rest against once inflated inside of the shell.

raw material to layer from the shell "4 millimeter thick steel"
https://wisc.space/blog/materials-scien … -starship/
https://www.nextbigfuture.com/2020/02/s … eight.html

ringsegmentsstarship.jpg

pick and chose the sections that make the most sense to build a shell for the inflatable to be contained within.

Cut the top of the tank and its might work the quickest

1585824.jpg

https://www.octalmetals.com/304-stainle … ate-sheet/


Bigelow is the only company with the patent to make what was once a Nasa owned thought which was made real over quite a period of time.

This is the test article for the use on the ISS but while its does fit inside of the Dragon cargo truck its only got the one port to it.
7RxvrKbYkyfYsjAzNZXJuZ-1200-80.jpg

They were shooting for the moonlgrush_190912_3664_0002.jpg
but since then Bigelow Aerospace laid off all of its workers The company’s hardships are the result of a ‘perfect storm of problems.’

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#91 2021-05-24 06:39:29

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For SpaceNut re arches ....

The concern you have raised about the surface of an arch being rough/not-even/not-smooth on the interior seems reasonable to me.

Traditional solution to that on Earth is to finish the interior of the arch with a cement like material, and then to paint the interior if it is to be used for living space.

The Arabs have been building arched buildings of dried brick for thousands of years.  This is ** not ** a new idea.

You have (quite rightly) brought up the issue of time it takes to make brick, and to position them.

There are two (Earth) years between Hohmann Transfer windows, so I would propose designing the robot equipment to complete the assigned task in two (Earth) years, so that the arched habitat cover is complete and ready for an inflatable component when they arrive.

Equipment can be designed and tested on Earth before it is shipped to Mars.

***
For OF re topic ....

Recently, in conversation with SpaceNut, I tried to think of the alternative futures that might arise from your initiative here.

The one that SpaceNut suggested is a kind of Wiki that would live/reside within the context of this forum.  That is actually quite feasible, and the work would become available to anyone reading the forum in future.  Since you have control of the topic (by agreement of the Administrators and Moderators) you can shape the content to provide the maximum possible benefit to future readers. 

You ** can ** edit any individual post, just as you would edit a paragraph in a paper.

The next option, which I had thought appealing, is to design the Primary to build content that could be transferred smoothly to an article for publication in a periodical via printed format, or perhaps via the increasingly common eBook format.  I have some elementary experience with that. 

Finally, a recent conversation with a member (it might have been Louis) awakened my awareness you could write a proposal directly to Elon Musk.

Mr. Musk (no doubt) already has staff thinking about what an expedition would look like.

You have a perspective and contacts not available to Mr. Musk or his staff, so a communication from you might be interesting to him/them.

I would be willing to work on a communication to SpaceX on your behalf.  I am confident the active members of the forum would be interested in shaping the correspondence, but you would be the one who ultimately prints out a hard copy and puts postage on an envelope to send it to SpaceX.

We are at least an (Earth) year away from that. 

(th)

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#92 2021-05-24 09:25:28

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For GW Johnson re OF's request ...

It appears that few of the currently active members of the forum are tuned into what OF is attempting ...

He asked for feedback on one of his posts, and nothing showed up.

I'm hoping you might be willing to teach (by example) how to respond to a serious request on a serious subject.

http://newmars.com/forums/viewtopic.php … 71#p180071

If you have not had a chance to review the Primary Expedition topic, please try to schedule some time for it.

My hope is this work will evolve into either

a) (SpaceNut concept) a Wiki-like series that will reside in this forum as is
b) (my idea) An article that will qualify for submission to a recognized print journal (or electronic equivalent)
c) (Something Louis inspired) A proposal to Elon Musk and the SpaceX staff

However, ultimately, everything depends upon what the author wants, and even he may not be certain at this point.

(th)

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#93 2021-05-24 09:26:33

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,270

Re: Companion fo Mars Expedition Number One; 17 crew members

Sierra Nevada Space Corporation has also developed a system of inflatable habitats which are suitable for incorporation into a commercial LEO space station. I suggested their designs in the parent thread to this one.

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#94 2021-05-24 11:04:34

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For OF re Primary topic ...

Would you be interested in making a five minute pitch to the North Houston chapter of the National Space Society on June 5th after 3 PM EST?

I've emailed an inquiry on your behalf, to see if they might be interested.


Presentation regarding the MS in Space Architecture master's degree program at the University of Houston.


----- Forwarded Message -----
From: NSS North Houston Space Society <info@meetup.com>
Sent: Monday, May 24, 2021, 7:19:33 AM CDT

Subject: ? Just scheduled: Monthly North Houston Space Society Chapter Meeting – Mahsa Esfandabadi – SICSA

Meetup

Nathan Price scheduled a new event in NSS North Houston Space Society Just now
Monthly North Houston Space Society Chapter Meeting – Mahsa Esfandabadi – SICSA

NSS North Houston Space Society
   

Saturday, June 5, 2021

2:00 PM to 4:00 PM CT
   

Online event

Link visible for attendees
Reserve your spot

Details

Join us for our Monthly NSS North Houston Space Society (http://NorthHoustonSpace.org) meeting. Connect with others who are excited about exploring the cosmos, learning how to use the resources of space to improve human life, and who want to go and s...
Hosted by

Nathan Price

Longtime space enthusiast. I stay up for SpaceX launches and Elon speeches. I work as a consultant for Anaplan but am looking for ways to get more involved in the exciting activities happening in Space Exploration.

I'm hoping at least one member of their audience might be interested in helping you think through what is required, ** and ** (hopefully) able to do so.

(th)

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#95 2021-05-24 19:11:08

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 24,438

Re: Companion fo Mars Expedition Number One; 17 crew members

Good that a second company has something but it has not flown yet as far I know...

In 2019, SNC delivered a full-sized ground prototype of the LIFE Habitat to NASA's Johnson Space Center. After living in the habitat for three days and going through a simulated mission, crew members gave the inflatable space habitat a positive evaluation.

inflatable-space-habitat-2-1200x.jpg

Sierra Nevada Corporation (SNC), has designed an inflatable space habitat made of a Kevlar-like fabric.

Dubbed the LIFE Habitat, the module is 27 feet long, 27 feet wide, and three stories tall when fully inflated. That's enough room for four astronauts, plus their science equipment, a medical center, and even an in-development space garden.

Gateway-inflated-w-credit-3-1-980x721.jpg

ratio3x2_1150.jpg

The inflatable is just set inside of the circular section and then inflated to full diameter with in the stainless structure. No arch is required but we will want to know what mass the shell thickness can withstand at a given thickness. If its not capable with the 1 shell thickness then double it up for gained strength...

When time allows for a redo of the external covering of soil then make an arch as time permits.

Mission 1 time is an enemy of the crew....

All images are open to the public for inclusion in the document we are trying to create.

Not to the adding of brick making equipment at some point we are adding a second cargo unit and then another and another to which we are playing with the mission profile and not really what we want to accomplish.

I would keep the number of starships to a minimum that are required until we know that 1 can not do it...

Preloading and waiting for equipment to do work is also a change of the mission architecture as its a crewed mission that we desire....

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#96 2021-05-24 20:47:16

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,742
Website

Re: Companion fo Mars Expedition Number One; 17 crew members

TH:  I am not sure what it is you want me to do.  Bear in mind that I am a very concrete sort of person:  vague generalities do not work with me. 

Bear also in mind that,  while I did successfully get my data recovered,  I still do not have a new computer. 

I can use my wife's machine on occasions,  but it is not set up or equipped for me to do what I used to do.  So,  in the interim,  I can provide calculations (etc) that I have already done,  or links to same. 

That being said,  my understanding of the topic at hand (which may or may not be accurate),  is to look at a 17-person crew on Mars.  These crew plus many tons of cargo would be sent there,  either by multiple Spacex Starships,  or by some sort of large orbit-to-orbit transport plus some sort of lander or ferry. 

I have looked at the best models of Starship that I can find,  and those feature (so far) an inert mass of 120 metric tons,  a propellant max capacity of 1200 tons,  and a payload of "100+ tons".  The very best mission requirements that I have are a factor-1.000 departure delta-vee from LEO of 3.659 km/s for an 8.6-month one-way Hohmann transfer at average planetary distances,  or 4.347 km/s for a fast 4.3-month one-way trip on a "2-year abort" orbit.  Either way demands a kitty of 0.5 km/s factor-1 delta-vee for 2+ course corrections,  and a factor-1.50 value of 0.533 km/s to land on Mars directly from the interplanetary trajectory.  By limiting payload,  you can cut tanker flights about in half.

Here are the data from "Rocket Vehicle Performance Spreadsheet" dated 9 Feb 2021,  located on my "exrocketman" site:

source     transfer        payload, m.t     propellant, m.t    remarks
Fig.2        Hohmann     353                     1200                      payload larger than capability to LEO
Fig.4        Hohmann     150                     686
Fig.3        fast 2-yr        248                     1200                      payload larger than capability to LEO
Fig.5        fast 2-yr        150                     879

The return voyage is actually more demanding,  and limits payload to smaller values.  However,  with propellant manufacturing on Mars,  getting a full refill is not a problem,  as there are no tankers.  Same article,  same site:

source     transfer        payload, m.t     propellant, m.t     remarks
Fig.6        Hohmann     100                     1200         
Fig.7        fast 2-yr        2                         1200                       reduced course correction budget to 0.4 km/s !!!

Now I did look at the LEO tanker problem,  using the same inert mass and propellant capacity for Starship,  plus 180 metric tons of Superheavy inert and 3400 metric tons of Superheavy propellant capacity.  The cargo starship needs about 20-25 tons of propellant for landing from orbit,  with its payload,  as an abort option,  while the tankers do not (they only need 10-12 tons to land).  This was in the 3-17-2021 article titled "Spacex Tanker Investigation".  The numbers come from Table 1 in that article:

configuration                                                             deliverable propellant,  m.t
dedicated tanker with extra tankage space          232
ordinary Starship flown at zero payload                192.5

To load 1200-20 = 1180 tons of propellant into a Mars-bound Starship with 248-353 tons of payload would require some 5.09 dedicated tankers (which is 6 tankers),  or 6.13 ordinary-Starship tankers (which is 7 tankers).  I'm showing Starship/Superheavy can only fly some 148-171 tons of cargo to orbit (depending upon what assumptions one makes).  The extra payload mass would require yet another cargo flight,  plus transferring many tons of cargo from one vessel to the other,  in zero-gee flight.  That last is NOT an attractive picture!

To load only 686 - 20 = 666 tons into a Mars-bound Starship carrying only 150 tons payload,  would require some 2.87 (really 3) dedicated tankers,  or some 3.46 (really 4) ordinary-Starship tankers.  Here the payload is set by the ferry capacity to LEO,  and the reduced propellant load cuts the number of tanker flights drastically.   This picture is quite attractive!

Musk has been talking about 2 unmanned cargo flights to Mars,  followed by the manned flight or flights.  I think that would be 2 more ships 2 years later,  for a total of 4,  with one returning.  Think 2 ships at 150 tons cargo each,  plus 2 more ships carrying cargo and crew.  Allowing 1 ton per person,  and putting 8 on one ship and 9 on the other (total 17),  you get 142 tons cargo plus 8 crew on the one ship,  and 141 tons plus 9 crew on the other. 

That's 583 metric tons of cargo and 17 crew,  if you deliver all of it with four Starship flights. 

For the return voyage,  17 crew is 17 tons,  plus a ton or two of Martian samples.  Call it a nominal 20 ton payload.  My numbers say that 100 tons is returnable via Hohmann,  but only 2 tons via the fast 2-year abort orbit,  and that's with a 20% reduction in your course correction kitty.  You can't get anything back that fast (4.3 months),  but there's loads of margin at 8.6 months back via Hohmann. 

Something in-between (near 6 months) should be possible at only 20 tons,  but with the full delta-vee kitty for course corrections.  I haven't run exactly those numbers.  Just bear in mind that you have about a crewed year on Mars to make some 1200 tons of propellant.  That's about 250 tons of methane,  and some 950 tons of oxygen,  at r = 3.8.  1200 tons per year is the required production rate,  with a crew on-site to handle troubles.

There is another option if something like RobertDyck's large orbit-to-orbit transport (or the ones I looked at in prior years on "exrocketman") becomes available.  You could use a couple of Starships sent unmanned to Mars as ferry craft from the surface of Mars to low Mars orbit,  and back.  They would have to be refuelled by propellant manufacture on Mars,  and at higher production rates than for the all-Starship mission described above.

I already looked at this some time ago. 

Although the numbers I used back then are now incorrect,  the trend shows that 100-ton-class payloads could be retrieved from low Mars orbit and returned to the surface of Mars.  This was on "exrocketman" as the article titled "Spacex Starship as a Ferry for Colonization Ships",  dated 9-16-2019.  I was using an 85 metric ton inert and an 1100 metric ton propellant load,  in those days.  The landing requirement was not quite high enough at 0.495 km/s,  the rendezvous requirement of 1.0 km/s was arbitrary,  and the factored to-orbit requirement was quite realistic at 3.621 km/s.  I think I probably ignored the 50 m/s = 0.050 km/s deorbit burn. 

However,  even with bad data,  the trend as reported in Fig.1 was fairly attractive:

payload, m.t                          propellant load,  m.t
100                                          650
200                                          990
234                                          1100

My guess (and only a guess it is !!!) is that at 120 ton inert and 1200 ton capacity,  a number near 100-150 tons might require only a near-capacity fill.  300 tons came with the two unmanned cargo Starships.  That leaves us to bring down about 283 tons cargo and 17 crew (total 300 metric tons) from an orbit-to-orbit transport.  You would need about 2 to 3 flights of a Starship (or Starships) as ferries.  That's about 2 to 3 1200-ton loads of propellant (2400-3600 tons) that you need to make during the 2 years between the unmanned flights and the orbit transport flight. 

That production rate is 1200-to-1800 tons per year,  for 2 years,  unmanned.  And you are screwed if there is trouble!  So this unmanned high propellant production rate is a really long pole in the tent,  for this mission scenario.  (The long pole in the tent for the all-Starship scenario is crashing Starships on Mars.)

You then have about a year to make another 1200 tons for the single flight back to the orbit transport,  for the trip home,  landing that Starship back on Mars robotically.  That's a 1200 tons per year rate,  with crew on-site to handle troubles.

This is all stuff that I have already done.  It applies to this mission plan.  Some of it needs updating,  but I cannot do that yet. 

Hope what I have offered helps. 

And,  yes,  I can teach others how I did this stuff.

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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#97 2021-05-25 06:20:10

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For GW Johnson re #96

First, thank you for picking up on my request dropped off in another topic! 

Second, thank you for your comprehensive summary of what OF can expect will be available for an expedition, using SpaceX supplied components.

Now ... to try to help ** you ** to understand what I'm hoping you might be willing to do ....

This is a request for you to help Oldfart1939 to organize his thoughts.

You won't need your spreadsheet or any of your articles, although it is certainly good to know you recovered the one and still have the other reliably available at the Wordpress site.

If your wife will allow you to use her computer, (and I realize that cannot be assumed), the request is that you bring your particular experience and proven good judgement to bear on his writing.

OF has specifically asked for feedback on his writing.

I am trying to help with the experience and abilities I have, but am hoping others will join in to give OF a boost.

It has been many years since he submitted his thesis to the committee, and many years since he built multiple companies.

The undisciplined free-for-all nature of the NewMars forum has taken a toll.

The task at hand is to create a work suitable for submission to a major publication (print preferably or electronic if necessary) or (and this is a stretch) suitable for submission to SpaceX for their consideration as they plan future missions.

Elon Musk is not and never will be a scientist.

OF ** is ** a scientist, and he has the distinct advantage of having thought about the Mars problem for a number of  years,

I am attempting to support OF in this endeavor.

SpaceNut has agreed to an experiment we are conducting.

OF has received assurance he is the only author whose posts will appear in the primary topic.

The Companion topic is set up so that all registered forum members can contribute.

However, OF has asked for specific feedback on a specific post, and to this point, no registered member has accepted responsibility to take on that request.

I am hoping you will do so.

We (all forum membes) need an example of how to provide useful feedback to an author.

From my perspective, this project should be quite similar to a thesis proposal ...

OF will be (in effect) asking a funding agency to give him the money to hire the people and procure the equipment and supplies needed for a two year expedition to Mars.

For 20 years, (or more) NewMars has been a science fiction paradise, and the archives are filled with the most astonishing visions and interesting related facts. 

This undertaking is a major step up from the norm for this forum, and it is challenging to try to pull it off.

Thanks again for your reply!

(th)

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#98 2021-05-25 08:20:51

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,742
Website

Re: Companion fo Mars Expedition Number One; 17 crew members

Now I understand better.  I am to look at the 17 crew topic,  and respond in the companion to 17 crew topic.  I am to help something get written by OF39. 

What I know about successful report writing goes counter to what "they" teach in tech writing classes: stay far away from "technish" jargon.  The format is basic English:  tell 'em briefly what you're going to tell them,  then tell them in detail,  then summarize very briefly what you just told them. 

From a practical standpoint,  you have to have clear in your mind exactly what you are going to write about.  Failing that,  your writing becomes obvious filler.  That is why I suggested a couple of mission scenarios.  OF needs to pick one and run with it.  Each such scenario is worthy of its own document.

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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#99 2021-05-25 08:42:21

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 8,641

Re: Companion fo Mars Expedition Number One; 17 crew members

For GW Johnson re #98

Thank you for your reply here!  I am asking for your help, because OF is planning (or at least I ** think ** he's planning) a piece that would qualify for peer review. And while the majority of registered active NewMars members are enthusiastic, creative and helpful, few are peers.

If you provide a demonstration of what peer review looks like, hopefully everyone else will try to emulate your example.

An  article for publication in Analog (as just one example) has characteristics that are fairly identifiable.  I have started a series about Analog fact articles, and have posted a couple of entries in the Other Space Index level.

There is always a set of references, and usually these are identified by footnotes in the work.

The forum members can assist by reading the references to be sure they match up with the citations. 

Forum members can assist by suggesting references that might support whatever theme OF develops as he goes along.

In my opinion, the expedition designer has absolutely NO need to be concerned about navigation to a site.

All the expedition designer has to do is to designate the site of interest, and then delegate responsibility to those who make a living doing navigation to and delivery of supplies.

There is no one right now who makes a living delivering people to Mars, but there are a great many people around the world engaged in laying the foundation for that achievement.

That activity can and (in my opinion ** should ** be ) left to them.

The Expedition designer is by necessity exploring, although data about the destination is already accumulating rapidly, and more will be available by the time the launches and landings occur.

(th)

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#100 2021-05-25 09:31:49

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,270

Re: Companion fo Mars Expedition Number One; 17 crew members

Just to let everyone here know what my mission format would be:

These are not well organized thoughts and are pretty much a stream of conscious ramble.

I envision there will be 4 Starships in this mission. One crewed vessel with my 17 member crew, plus 3 other freighters. The freighters will NOT return to Earth, and will later be cannibalized for building supplies and possibly as repair parts for the crew return vessel. There will be a superabundance of food and survival type supplies. I envision the possibility of a mission return problem caused by inadequate fuel production. Remember: Murphy was an optimist. The 2 freighters will create a 100% surplus, should they both land intact and not have any sort of RUD activities. I'm a believer in redundancy of essentials, of which food and shelter are most important. I earlier stated that we need to consider the possibility that there will be inadequate fuel and Oxygen production in 500 days for a mission to accomplish Earth return safely. I'm planning on the possibility of missing the first Hohmann transfer opportunity and the crew will be there for 3 years instead of 18 months. I'm planning on the Zubrin model of Mars Direct for power requirements: there will be 4 nuclear reactors taken along. One on each Starship, so power will not become an issue. Solar power will also be utilized as battery recharge power during daylight hours; if everything survives there will be lots of regolith moving capability with up to 6 Bobcat-style tracked front end loaders. With my construction Triad, 3 would be in operation at any given time while 3 are in battery recharge/maintenance mode.

You will note that my 3 most essential requirements listed are: (1) Shelter, as described in the primary thread; (2) Food in abundance; (3) Adequate power. Exploration and doing science will follow simple survival in importance, and manufacturing an adequate supply of Oxygen and Methane will be the first task.

I envision that the Habs will be as something as I described in the primary thread; buried in trenches excavated by the loaders, and after setting up the Nuclear reactors and Sabatier reactors and Moxie units, are next on the list. This is why there are 6 construction type crew members. Three will be involved in dealing with the nuclear reactor setup and starting a Sabatier reactor and either a Moxie unit or if water is close at hand--electrolysis system. Preferably BOTH. This leaves 3 construction crew to do the digging of the habitat shelter trenches and moving the inflatable structure into position, then construction of the prefabricated arches over the inflatables, followed by partial inflation while being buried with regolith, and finally put into service.

The sequence of importance for the Habitat modules: (1) sleeping and sanitation facilities; (2) dining and food preparation; (3) Shop and maintenance module (Larger in diameter and higher ceilinged); (4) laboratory and medical facilities; (5) headquarters and data/communications facility. The Starships will serve until each of these is fully functional.

Last edited by Oldfart1939 (2021-05-25 09:37:33)

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