Author Topic: Sequencing of deliveries for building a Mars base with Starship  (Read 75924 times)

Offline Slarty1080

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Assuming the goal is to build an initial settlement of 10,000 tonne settlement for 100 people and for it to be relatively self sufficient, what is the best sequencing of cargo? There will be disagreement over timing (no doubt) but that shouldnít matter so much to the ordering of deliveries. Deliveries might be classified as living space, power capacity, agricultural space, capacity for producing these three in situ, experimental and scientific payloads, people and their supplies.

In order to do this calculation in a logical way there needs to be some rational comparative basis. So I suggest using METís Mars Equivalent Tonnes. 1 tonne of useful structure on the surface of Mars counts as 1MET. Add to this the tonnes of useful materials it can produce over its expected lifetime and subtract from it the tonnes of useful materials it will consume. It should also be possible to come up with a rough cost in MET for 1MW of power using this system.

It would be very beneficial to develop this bare skeleton of an idea into a workable calculation (and yes it needs a lot of work but hopefully you get the scope of the idea) before everyone jumps in with their own numbers to prove that everything can or canít happen by year x. A forlorn hope perhaps, but Iím an optimist.
My optimistic hope is that it will become cool to really think about things... rather than just doing reactive bullsh*t based on no knowledge (Brian Cox)

Offline Slarty1080

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Reserved for a summary later after discussion
My optimistic hope is that it will become cool to really think about things... rather than just doing reactive bullsh*t based on no knowledge (Brian Cox)

Offline rakaydos

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Solar cells and fuel plants are key. Not only for reuse of the supply rockets, but also as feedstock for more advanced ISRU. a local chemical industry, and a local foundry, may be able to boostrap to simple photovoltaics, allowing some measure of local growth WITHOUT spending "Mars equivilant tonnage."

Offline Oersted

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Wel, those who know me from other threads won't be surprised that I think a tunnrel-boring machine, a truck and a roadheader (plus repair and maintenance gear) should go up pretty early in the process, so they can start building an unlimited amount of internal space. When they have got that underway THEN they can start actually filling up the internal space created. 

Offline Eer

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... So I suggest using METís Mars Equivalent Tonnes. 1 tonne of useful structure on the surface of Mars counts as 1MET. Add to this the tonnes of useful materials it can produce over its expected lifetime and subtract from it the tonnes of useful materials it will consume.
...
Point of clarification - do you mean "subtract from it the tones of useful imported materials it will consume"?
That is, don't count locally sources materials, solar energy, etc., but DO count the tonnes of materials imported from Earth, Moon, or other deep gravity wells.
From "The Rhetoric of Interstellar Flight", by Paul Gilster, March 10, 2011: Weíll build a future in space one dogged step at a time, and when asked how long humanity will struggle before reaching the stars, weíll respond, ďAs long as it takes.Ē

Offline Slarty1080

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... So I suggest using METís Mars Equivalent Tonnes. 1 tonne of useful structure on the surface of Mars counts as 1MET. Add to this the tonnes of useful materials it can produce over its expected lifetime and subtract from it the tonnes of useful materials it will consume.
...
Point of clarification - do you mean "subtract from it the tones of useful imported materials it will consume"?
That is, don't count locally sources materials, solar energy, etc., but DO count the tonnes of materials imported from Earth, Moon, or other deep gravity wells.
Ultimately I'm thinking how many tonnes of Mars base can be built per tonne on cargo delivered from Earth. Initially it will be one tonne imported for one tonne of base, but as time progresses one tonne of imported brick manufacturing kit might build the equivalent of 10 tonnes worth of habitat. And 1 tonne of agricultural unit should count as 1 tonne towards the base plus say 100kg/year of food that does not have to be imported.

There are lots of awkward issues to iron out that I'm hoping to identify them and come to some vaguely reasonable calculation.
My optimistic hope is that it will become cool to really think about things... rather than just doing reactive bullsh*t based on no knowledge (Brian Cox)

Offline Greg Hullender

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I don't think there would be any solar cells at first. Instead, they'd ship nuclear reactors, at 1500 kg/10 KWe. That's definitely what NASA is thinking.

Online wannamoonbase

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First step, power.

Nuke for baseload, keep a site running through a lunar night, Add PV and battery storage with more flights.

Second:
Modules or structures that provide usable habitat volume would use the power. Grow plants soon  in a greenhouse for food and naturally convert CO2 to O2.  That would require a permanent presence though.

Third:
A sizeable rover for extended mobility

Fourth:
Start working up the ISRU capabilities.
Superheavy + Starship the final push to launch commit!

Offline rakaydos

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I don't think there would be any solar cells at first. Instead, they'd ship nuclear reactors, at 1500 kg/10 KWe. That's definitely what NASA is thinking.
NASA can plan for nukes, because NASA has links to the DoE.  As a private civilian, Elon intended to brute force solar until someone ELSE figures out the paperwork for nukes on mars. Someone not him.

Nuclear power vs solar power is like isogrid milled aluminum/lithium alloy, vs stainless steel. Some advantages, tons of cost and headaches.
« Last Edit: 04/28/2021 07:39 pm by rakaydos »

Offline steveleach

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If I've learned anything from playing games like Planetbase (clearly the most important source of robust engineering insight in this conetxt), it is that you can't focus too heavily on any one thing.

Build a bit of everything, then a bit more of everything, etc.

Only focus on one-big-thing(TM) when you absolutely have to, and only when everything else is running sweet as a nut.

Or not.

[edit: typo]
« Last Edit: 04/28/2021 07:48 pm by steveleach »

Offline Slarty1080

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I don't think there would be any solar cells at first. Instead, they'd ship nuclear reactors, at 1500 kg/10 KWe. That's definitely what NASA is thinking.
I think nuclear is the way to go, but I'm not sure how ready it is, when it will be or what the political challenges will be
https://physicstoday.scitation.org/do/10.1063/PT.6.2.20201223a/full/
My optimistic hope is that it will become cool to really think about things... rather than just doing reactive bullsh*t based on no knowledge (Brian Cox)

Offline Vultur

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I don't think there would be any solar cells at first. Instead, they'd ship nuclear reactors, at 1500 kg/10 KWe. That's definitely what NASA is thinking.
NASA can plan for nukes, because NASA has links to the DoE.  As a private civilian, Elon intended to brute force solar until someone ELSE figures out the paperwork for nukes on mars. Someone not him.

Nuclear power vs solar power is like isogrid milled aluminum/lithium alloy, vs stainless steel. Some advantages, tons of cost and headaches.

Yeah.

Also, is 1500kg for 10 kilowatts even that good compared to modern thin film solar?

Mars solar constant is like 500W/square meter.

Say 1/8 of that for night + dust + poor sun angle, 20% efficiency = 12.5W/square meter.

Thus 1000 square meters = 12.5 kW.

What's the mass of thin films per square meter?

Offline jabe

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Power and isru machinery. Regolith movers. lots of arduino/raspberry pis and lots of ic chips/small motors to control things you make using materials made by isru process
« Last Edit: 04/28/2021 10:54 pm by jabe »

Offline AU1.52

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If we stick with Solar power initially they will need to think of easy ways to keep them free of sand and dust. Having them on a mount a little about the ground and have them shake a little every few weeks may help clear the dust.

Offline AC in NC

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I don't think there would be any solar cells at first. Instead, they'd ship nuclear reactors, at 1500 kg/10 KWe. That's definitely what NASA is thinking.
I think nuclear is the way to go, but I'm not sure how ready it is, when it will be or what the political challenges will be
https://physicstoday.scitation.org/do/10.1063/PT.6.2.20201223a/full/

My recollection of previous discussions was that Solar was considered far superior for initial power requirements.  Solar beat nuclear on a power/kg basis and there's nothing readily available to scale up nuclear in the capacity required.

I thought this was pretty well settled.  A few kilopower units aren't going to make a dent.

Offline Greg Hullender

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What makes solar expensive on Mars is that you have to bring enough batteries to survive a weeks-long sandstorm that blocks 99% of the light from the sun.

So taking 645 W hrs/kg for the specific energy of NASA's best batteries, I figure you'll need about 8 metric tons of batteries to provide 10 kW of power through a 3-week sandstorm. That's pretending the solar cells themselves are zero-weight.

That's 8,000 kg of batteries vs. 1500 kg of reactor. And that's assuming 3 weeks has enough safety margin.

Once you've got enough base power from nuclear, though, you could use solar for everything else. You'd have an emergency low-power plan, where everyone would crowd into one or two shelters for up to three weeks. But with no nuclear at all, then if the batteries run down, everyone dies.

Offline Greg Hullender

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I thought this was pretty well settled.  A few kilopower units aren't going to make a dent.
When I work through the numbers for solar, including enough batteries for a 12-hour night at aphelion (but ignoring sandstorms), I come up with about 6 or 7 W/kg--just about the same as for Kilopower. Can you find a link to any of those older discussions that reached a different conclusion?

The fact that the human colony cannot ever lose power makes solar a lot more expensive than it would be for a rover that can just hibernate for a while if it has to.

Offline AC in NC

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I thought this was pretty well settled.  A few kilopower units aren't going to make a dent.
When I work through the numbers for solar, including enough batteries for a 12-hour night at aphelion (but ignoring sandstorms), I come up with about 6 or 7 W/kg--just about the same as for Kilopower. Can you find a link to any of those older discussions that reached a different conclusion?

The fact that the human colony cannot ever lose power makes solar a lot more expensive than it would be for a rover that can just hibernate for a while if it has to.

It's a lot to sort through and I may misremember but maybe start with this post and the one following and branch out from there:  https://forum.nasaspaceflight.com/index.php?topic=39785.msg2071748#msg2071748

Offline Nevyn72

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Solar needs to account for all the support equipment such as frames/mounts, connecting wires, inverters & regulators, etc. It's more than just the panels, potentially double the weight of the panels alone....

As for shortfalls during poor conditions? Why double up by bringing in Nuclear just for that?
Nuclear for it's own reasons, sure, but not for shortfalls during poor conditions.

You already have a large ISRU setup producing Methane and Oxygen and storing it. (theoretically)
Just tap into this supply using a fuel cell or turbine for the period required. Use what you have already!

Offline Ludus

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The question was about the first 10,000 tons of cargo about 100 Starship loads that would with the first 100 humans create the basis of a permanent settlement.

That suggests itís not necessarily about whatís on the first few Starships supporting the first 10 humans. Their job includes understanding local resources at the site in detail to prepare for the major waves of cargo ships.

While nuclear reactors like the Megapower sibling of Kilopower arenít ready now, they seem much more appropriate to this than Kilopower. https://inldigitallibrary.inl.gov/sites/sti/sti/7365867.pdf

Iíd think that appropriate to 10,000 tons, 100 cargo Starships would be a whole series of Deployable turn key Starships that are ready to handle some feature of infrastructure once they are moved into position and plugged in. An example is a Power Starship with a Megapower reactor built in. This is 5MW Thermal, 2 MW electric.

Some would be habitats ready to be filled up with local water in wall tanks to provide radiation shielding. Some, ISRU plants to purify water, make oxygen, make methane.

If theyíre Solar PV Starships, they might have built in battery packs and all the gear to deploy a complete Solar plant.

Early on, there ought to be equipment to make landing pads and roads out of local materials and some system to pick up Starships and move them around on the ground to where they are needed.
« Last Edit: 04/29/2021 01:02 am by Ludus »

 

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