
A Minimal Architecture for Human Journeys to Mars - idlewords
http://online.liebertpub.com/doi/pdfplus/10.1089/space.2015.0018
======
mc808
To me it makes a lot more sense to start with a few decades of robotic mining
and construction (and release publicly funded technology to the public domain
so it can also benefit the 99.99999% of Earthlings who will never step foot on
Mars). Get some infrastructure and fail-safes in place instead of sending
people to almost certain death in a minimally viable mission, which would be a
PR disaster.

~~~
VikingCoder
> PR disaster

I keep saying it... There are billionaires alive today, who might actually
chose to die on Mars. They could do it.

If James Cameron, Richard Branson, or Elon Musk decided they wanted to die on
Mars, I think they could make it happen. And I don't think it would be a big
departure from their personalities.

And I don't think it would be a PR disaster.

I think it would be inspiring as hell.

"All men die. Not all men truly live. Follow me to Mars. Colonize it. Make it
a second home for humanity. Life is too precious to keep all of it in one
basket."

~~~
Someone
They may want to die on Mars, but I doubt they want to spend a year or so of
their life in a moving prison.

Billions do not buy you much in terms of comfort on the way to Mars.

Yes, it Will be hard for non-billionaires, too, but they will give up less,
and have more to gain; they aren't famous yet.

~~~
VikingCoder
"James Cameron becomes first solo explorer to reach the deepest point on
Earth. This was his 73rd trip into the ocean in a submersible, including 33
dives to the Titanic."

He also worked as a truck driver for a while...

...and he'd probably bring VR along, and have multiple crews back on earth
filming anything he wanted to see...

And I'm talking about them near the end of their lives... I could envision it
happening.

------
Paul_S
I will accept halving of my salary if we can start making an effort towards
Mars colonisation. But we all know that any extra money would be spent on
building vanity structures here or earth and other forms of culture I don't
appreciate.

We can send a robot mission to Mars or build another Olympic(tm)(r) stadium. I
wish I was joking.

~~~
Mahn
On that note, how come no government has entertained the idea of opening up
tax money budget allocation, e.g. by letting citizens vote on where they want
their money used? I understand that the average citizen has little or no idea
of how to run a country, but still, surely decisions like whether to build a
stadium or send people to Mars could be debated.

~~~
keenerd
I recall at least one short story with that. (Eugene by Greg Egan) The main
character previously worked in Social Security, who had to lay off everyone
due to no one giving them money.

Anyway, you can directly donate to NASA. They just aren't allowed to promote
it or somesuch.

[http://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID=N_PD_...](http://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID=N_PD_1210_001G_)

~~~
daheza
Has anyone done this before? Looking at this page it doesn't really list where
to mail a check to or who to make that check out to.

~~~
Paul_S
[http://www.penny4nasa.org/donate/](http://www.penny4nasa.org/donate/) allows
you to donate even through dogecoin.

~~~
keenerd
None of that money goes to NASA.

~~~
Paul_S
Oops, you are absolutely right, I'm sorry. Serves me right for not even
reading the faq.

------
Gravityloss
You could launch most of this stuff with reusable Falcon 9 rockets or
equivalents. You just have to divide the building blocks to about ten tons a
piece. A large portion of mass is just propellants which is very easy to
divide. Space assembly, docking, arm capture, berthing and in space refueling
are all quite routine concepts nowadays. When you don't need the SLS, a lot of
missions become a lot cheaper and also flexible.

Example: you have a reusable 10 ton vehicle and you need to send a 150 ton
mass to orbit. You fly once per week for four months and it's there. After
that the vehicle/capability can be used for something else. Think of it as
renting a standard truck. It's cheap since there's a large supply because of a
large market. Their utilization rate is relatively high, meaning when you use
them, you only need yo pay a small portion of the investment and upkeep. You
can rent many for long periods of time if you need to. On the other hand large
custom moving equipment is expensive and not always even available. And they
can stand idle for long periods of time.

~~~
Solarsail
A possibly irrelevant nostalgic detour, but I'm reminded of a thought
experiment I contributed to once [1].. Called Mars 9 Tons at a Time. Basically
use Zubrin's Mars Direct as the baseline plan, but do it without the Ares 5 he
described or another HLV. Which has the effect that we would launch everything
direct to Mars, no rendezvous or docking prior to the Martian surface.
Primarily on the hypothesis that docking the parts together would add the cost
of an assembly facility, and complicating the components enough to be dock-
able together or heavily suboptimal to support simple assembly.

But to avoid the costs of the Ares V, we wanted to do the entire thing using
nothing but existing off-the-shelf available LVs to do the entire thing. If
we'd gone the route of even a small custom LV, we would have the constant
overhead of maintaining multiple launch pads that sat idle for 2 years at a
time, just to launch something each launch window to Mars. Instead, our plan
began with the Delta IV-H lobbing payloads trans-Mars. It has a payload of
just over ~9T doing that. It could also fly three or four payloads per launch
window, Vandenburg and the Cape, both at the start and the end of the window
for a two week turnaround on each launch pad. Of course, suboptimal timing and
suboptimal inclinations will cut into that 9T slightly. Further, we could make
use of things like the Mitsubishi H-IIA [2], Atlas V 551 or Heavy (would need
modest new development, or the 551 which is a bit weaker), Ariane V and maybe
Proton (tho Proton is quite weak on high energy flights). Falcon 9 Heavy could
eventually be added to that list (I think we were already talking about F9H in
2007...). That gets you maybe 6-9 payloads per launch window to Mars, of 6-9
tons depending on the launcher. That was our working budget for each payload.

We managed to account for just about everything to do with the surface base
using nothing but those small payloads... Planned out a standard design for a
small descent vehicle in I think 1500kg to 2500kg which could land most of the
rest of the mass as payload. We could do Earthworks (or Marsworks...
dirtmoving / digging) using using some small remote-controlled construction
equipment of 2-3T each. [3] Food, water and other supplies could pretty easily
fit in smallish pieces like that. Used solar panels in place of Mars Direct's
nuke for political feasibility / scalability to small payload deliveries. Also
talked a bit about assembling a shelter using either the landed capsules for
rooms, or assembling rooms from parts (I don't remember which). A part I was a
bit uneasy about that some others thought was trivial enough, was building a
new launch vehicle from parts on the surface... We'd be using small modular
segments to build stages, scaffolding to assemble everything together and
connect the stages, and all of this would be done outdoors. I was kinda
worried about getting sand between the staging components or in the engines.

The part we didn't manage to fit into the initial constraints of 9 ton
payloads, all direct-to-Mars, was the actual crew transport there (we were
fine-ish for the return). We stretched kinda far, pulled compromises nobody
would really take, and got a 1-crew capsule to weigh in at 11T-12T. And that's
with basically no redundancy! The entire thing would be a small can with a
solar wing for power, life support for 6 months, and no way for the pilot to
survive a launch failure from Earth. The capsule would fly straight to Mars,
pilot would don a suit, depressurize the capsule and get in a MOOSE-alike [4]
module and travel to the Martian surface in that. They would also be dependent
on the entry trajectory for their life, as they'd have to walk to base on
landing.

From there our plans started to look a bit more "traditional" with either an
HLV snuck in there just for the crew (and not the base) or orbital assembly of
an orbital ship. Say, something with plenty of life support of its own, just
does Earth-Mars-Earth and gets the crew to and from the base. The ship itself
would be a rather substantial project to build, but at least it could ignore
landing much payload. And the ascent vehicle from Mars would only need to
worry about orbit, not escape velocity.

[1][https://web.archive.org/web/20070810053610/http://uplink.spa...](https://web.archive.org/web/20070810053610/http://uplink.space.com/postlist.php?Cat=&Board=businesstech&page=0&view=collapsed&sb=5&o=0)
Ok, so the thread Mars 9 Tons at a Time wasn't archived at all. But there it
was, August 2007.

[2][https://en.wikipedia.org/wiki/H-IIA](https://en.wikipedia.org/wiki/H-IIA)

[3]
[http://www.cat.com/en_US/products/new/equipment/excavators/m...](http://www.cat.com/en_US/products/new/equipment/excavators/mini-
excavators/18172626.html) For example, is a smallish piece of equipment which
can take many different parts on the end of the arm, work very slowly as a
bulldozer, and fit inside our payload budget. We'd need something mechanically
different, but probably that size / style of machine, to work remotely in very
low temperatures. Shortly after our that thread, one of the construction
equipment companies produced concept art describing something like that on The
Moon with actuators (I think) in place of the hydraulics. Some folks
complained that they were just advertising their stuff on The Moon to look
cool.

[4]
[http://www.astronautix.com/craft/moose.htm](http://www.astronautix.com/craft/moose.htm)
Not terribly confidence-inspiring.

~~~
Gravityloss
Interesting!

If you want to avoid space assembly, you can always just refuel. Even that
gets you far since in many cases propellants are a large proportion of
spacecraft mass.

But why would you avoid docking?

Even Apollo had it as a critical part of the mission. Twice! (The CSM turned
around and docked to the lunar module after translunar injection.)

~~~
Solarsail
Well, the avoidance of docking was primarily because this was a thought
experiment, not quite optimizing for a global optima. We wanted to see if a
Mars mission could be mounted within those tight constraints, and set about
with those constraints as unwavering. Why avoiding docking was one of them,
was a requirement from Mars Direct. (Flipping through A Case For Mars for a
minute wasn't enough to find the reasoning...) If you wanted to do a mission
with minimal assembly but with docking... I'm not sure you could get a ship
with a dry mass of <25T to launch to LEO. Say, with a sizeable upper stage for
orbit insertion, habitat module and life support storage space (even with the
food / water / fuel all brought up later). Even a fairly large Bigelow module,
electrical equipment and pressurized space for food is going to be more than a
Delta IV-H can take to LEO... And then an empty upper stage big enough needs a
lot of volume. Maybe two flights for assembly, and then launch supplies up?

------
Trombone12
"Barring some compelling geopolitical phenomenon, there is not likely to be
another ‘Kennedy moment,’ and the NASA budget is unlikely to see a dramatic
increase"

and

"Furthermore, although not considered here, international contributions could
offset some of the cost"

oh Americans, there is a wider world out there across the border you know...

~~~
njloof
And miss the chance to put our flag first on Mars? I think not.

~~~
netcan
I dunno…

I think space exploration _is_ a great chance for human solidarity.

Funding, control, bureaucracy and such can still be challenging, but I think
the scientists and engineers themselves would generally be on board. The
public also, I think/hope.

Planting an earth flag instead of a national one kinda makes simple sense that
I think will appeal to people. You land in a new land, you claim it for your
land. Land on a new planet, claim it for your planet.

~~~
logingone
Did you see all the little american flags come out when New Horizons reached
Pluto. I found that a little disappointing. As deliberate as unnecessary.
Almost looked tit-for-tat following the EU cheer at Rosetta.

~~~
netcan
No, but I'm not american so the media doesn't play that angle so much here.
But, I'm not looking to berate anyone for flags. Nationalism/group thinking is
part of how we work. If American flags are being used to explore the universe
and take steps for mankind, I'm not mad at them. I also don't think americans
are the worst at this, for all the flak they get.

On the other hand, I'm totally behind anyone who wants to internationalize it.
Like I said, I'm pretty optimistic that if it starts people will dig it.

I would be proud to see an earth flag flying on new worlds, especially if they
have wind. I think other people would be too.

[http://2.bp.blogspot.com/-bA-
pR_9s6Ng/VVeBWoDKeHI/AAAAAAAAAc...](http://2.bp.blogspot.com/-bA-
pR_9s6Ng/VVeBWoDKeHI/AAAAAAAAAcc/wv7sIdbwW80/s1600/United%2BTerra%2BFlag%2BHoisted.jpg)

------
jkot
There is great sci-fi novel Voyage from Stephen Baxter which describes such
minimal mission. It is alternative history where NASA landed on Mars in
1980-ties.

------
nkoren
Six SLSs for a crew of 4 to spend 24 days on the surface. At first glance,
this is a _wildly_ inefficient mission architecture.

~~~
thanatosmin
I have to imagine that if this could be done more efficiently, that plan would
be in this proposal.

~~~
nkoren
Yeah, you'd like to imagine that, but unfortunately it isn't the case. Here's
a perfectly credible and very well-studied architecture for a Mars mission
with 1/3rd the upmass and ~540 days on the surface. If your objective is time
on the surface to inhabit and study Mars, then this would give a 64x better
return on your investment:

[https://en.wikipedia.org/wiki/Mars_Direct](https://en.wikipedia.org/wiki/Mars_Direct)

So why propose something much more expensive with much less return? Because
scientists have learned that the NASA projects which get funded and stay
funded aren't the projects which are most cost-efficient; they're the projects
which spread the money around to as many NASA centers (and, more importantly,
states which correspond to the senior members of the Senate Appropriations
committee) as possible. That's pretty obviously the guiding light for this
architecture; its innovation is that it proposes to do so within _existing_
budgets rather than radically expanded budgets. But that doesn't make it
minimal or cheap by any measure.

~~~
simonh
Because nobody is building any of the components for Mars Direct. However many
of the components for these missions either exist already or are currently in
active development. To do Mars Direct now you'd have to factor in the cost of
scrapping everything that's currently in the works and developing Mars Direct
from scratch.

I appreciate your POV, Mars Direct is a compelling plan, but it's weakness is
that none of its components except the launcher are any use for anything else
except another Mars Direct mission. Anyway it's a bit unfair to thrash these
guys for wanting to work within what is already actually happening.

~~~
nkoren
In other words, they're stuck in the Sunk Costs fallacy:
[https://en.wikipedia.org/wiki/Sunk_costs](https://en.wikipedia.org/wiki/Sunk_costs)

~~~
simonh
I don't think you properly understand what the falacy is. The falacy is to
factor in a sunk cost that has no future value in future decisions. For this
proposal to be subject to that falacy, you'd have to show that the products of
the current development programs have no future value.

~~~
nkoren
I'm afraid I have to turn around and say that it is you who does not have a
proper understanding of the sunk costs fallacy. The future value of the sunk
costs is not important -- in fact, thinking that it is important is the very
definition of the fallacy. Rather, the future value of _all_ costs is what is
important, whether those costs are sunk or not.

To illustrate, here's a simplified example. We can buy one of two Mars
missions: Mars Mission A, which costs $100, of which we have already paid a
$10 non-refundable deposit, and Mars Mission B, which costs $30, but we have
not yet spent anything on it.

The $10 we have already spent absolutely _does_ have future value -- $10 worth
of future value, if we pursue Mars Mission A. Its future value is, however,
irrelevant, because Mars Mission A has $90 worth of future costs, compared to
$30 of future costs for Mars Mission B. The Sunk Costs Fallacy is to believe
that the $10 continues to have any relevance in such a scenario. In truth, the
future costs are the only costs which matter.

------
lmm
These sound very similar to Kerbal Space Program mission plans (which I guess
speaks highly of it as a simulator). I'm tempted to try to fly it all ingame.

Has docking with (unpiloted) prepositioned stages been demonstrated in real
life? Is it reliable enough to use when crew lives depend on it?

~~~
T-A
It was perfected (for some value of "perfect") in the 60s, during the Gemini
program:
[https://en.wikipedia.org/wiki/Agena_target_vehicle](https://en.wikipedia.org/wiki/Agena_target_vehicle)

------
vixen99
I'd like to see more on how it's proposed to protect the travellers and the
long-stay Mars migrants from radiation. The dosage numbers I've seen do not
seem encouraging. Isn't this a major, possibly fatal stumbling block to
extensive space exploration?

~~~
Retric
10.3 m of water + a strong magnetic field gives you approximately the same
protection as the earth's atmosphere. Sadly, that getting that much mass in
orbit would be extremely expensive, but a shield provides a long shadow of
safe area. Though, in the long term such a shield could be reused indefinably.

On Mars the easy option is to live in a cave.

And, considering the other risks involved I think many would trade a
significant increased risk of cancer in their lifetimes for the journey.

------
danieltillett
The crazy thing about all the Mars missions I have read about is they
optimising for the cheapest component - the humans. Until we have a problems
finding volunteers then this is very suboptimal.

~~~
onion2k
There might be a long queue of people willing to volunteer but 99.9999% of
them would be incapable of doing the job so the mission would fail. Most would
give up before they leave Earth. A lot would break down and make errors during
the travel. Of the remaining few, most wouldn't be able to do useful science
at the other end. If you want the mission to be more successful than "Yay, we
got a human corpse to crash on Mars!" then you need to optimise for attracting
people who can actually successfully execute the mission operations. _That_
isn't so cheap.

~~~
danieltillett
Sure 99.9% of all humans might not make the grade, but out of 7 billion people
I think we can find more than a handful who would.

In the end it does not matter as you optimise to the level you need to attract
the candidates required to do the job. Anything else is just over engineering.

Edit. I don't think we would have a major problem attracting Apollo-level
candidates even if the chance of success was less than 50%.

~~~
pstuart
Or once we have real AI it could run the mission and the humans would be more
like passengers who could spend most of the trip in some kind of suspended
animation.

~~~
danieltillett
You don’t even need real AI to do this. Years ago I worked out a way to get
humans to mars for under 1 billion per person by using off the shelf
components and existing infrastructure by not optimising for humans. I should
write it up as it is at least entertaining (most people I told were equal part
horrified/impressed).

~~~
pstuart
Please share your write up if you get a chance.

I was being a bit playful with 2001: A Space Odyssey

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TheGrimDerp1
Ya know what would be fun? building a huge space-ship. I feel like people
over-think it sometimes. buildtheenterprise.org

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juhq
There should [pdf] flag or something in hacker news.

~~~
DanBC
There's a suggestions thread. I'm not sure how often that gets read by the
mods. Or you could email them - they seem pretty receptive. Having some tag
for PDF / Video / Audio would be good.

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couchand
Am I the only one seeing a Unicode issue in the title?

~~~
8_hours_ago
It is U+FFFC, the OBJECT REPLACEMENT CHARACTER. The Unicode spec says it is
"used as placeholder in text for an otherwise unspecified object".

[http://www.unicode.org/charts/PDF/UFFF0.pdf](http://www.unicode.org/charts/PDF/UFFF0.pdf)

The weird thing is that this is the second time I've seen it today, and I
don't think I've ever seen it before...

