

NASA’s Balance Mass Challenge - lochieferrier
https://www.innocentive.com/ar/challenge/9933607

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drzaiusapelord
>Balance mass should perform some type of scientific or technological function

So that's 661 lbs. I wonder how far we are from a solar powered 3D printer.
Can we build a self-replicating robot of any kind that would work on Mars?
What practical raw materials could a machine tap, if any? Imagine this
platform being used to test off-planet manufacturing. Even on a small scale it
would be pretty impressive.

Didn't the Mars society have a proposal for a low cost Mars mission with
automated missions flown before-hand performing some kind of fuel extraction
from Mars (hydrogen?) So that when humans landed, they'd tap these reservoirs
of fuel instead of paying all this money to fly fuel with them. Even a small
scale test of that would be a game-changer.

If that's too lofty, get 50 colleges to make mini robots/sensor/whatever with
a 6lbs limit, kind of like we do with CubeSats today. That leaves NASA ~350lbs
for a lander to safely drop these things. Having just one single winner seems
a little short-sighted. I'd rather see lots of people given the chance to drop
something on Mars than just one group.

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yasth
No you can't create self replicating anything in that space. The big issue is
the chip fabrication.

You might be able to test making rocket fuel, but the practical point of that
is probably not great (we already know it will work) as you couldn't store a
useful amount, and at the moment there is nothing in the pipeline that would
use it.

Also only 150kg is dumped during entry. The other 150kg have a much rougher
task to survive descent. (As the doc says "material surviving atmospheric
reentry would impact the Mars surface approximately 10 minutes after
separation at nearly 9,000 mph (4,000 m/s)."

The 150kg that is dumped during the entry phase is still going to have a real
rough time of it mind, but it is an easier task.

Small cube-style sensor dispersal would be unlikely to survive, could pose
substantial risk of main craft damage, and would be unlikely to have enough
radio power. Also these things have to be _dense_ there is not a lot of volume
to work with.

It is a challenge, because it is actually fairly challenging.

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voxic11
Even if its not fully self replicating being able to create the bulk of the
structural mass and maybe even basic batteries would save a huge amount of
fuel costs. Then you only need to bring control systems, motors, and
radioisotope generators to mars rather then a bunch of multi ton robots.

~~~
yasth
Can't be done in that space or that mass. The hard part isn't the 3D printing
(and that isn't easy, as anyone can tell you 3D printing in a controlled
temperature environment with precision manufactured feed stock is still a bit
touchy, using on site crafted feed in an environment that shifts 100 degrees
Celsius day to night is going to be very challenging) it is the materials
extraction and processing. You basically have to mine, refine, and mold
Martian soil into whatever end product you have, and you have no fossil fuels
to get things up to temp.

To do so at all would be a massive undertaking, to do so at any kind of scale
in 300 kg (assuming that magically you ended up recalculating the trajectory
or something to get all 300kg in one group on the surface) is, I'm pretty
sure, beyond our technology at present.

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raldi
_> Payloads replacing Balance mass should perform some type of scientific or
technological function adding to our knowledge base while closely matching the
volume and weight characteristics of the original Balance mass._

Um, the one being replaced was solid tungsten, which is almost twice as dense
as lead. How is anything going to come close to matching that?

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svsaraf
> Because of the high density of tungsten, it is unlikely that payload
> concepts may be proposed that identically match the characteristics of the
> MSL BMDs. To maximize the potential for innovative concepts while still
> achieving the desired spacecraft EDL performance, NASA is requesting that
> proposed concepts target 90% of the original MSL BMD mass while matching the
> volumetric dimensions used for MSL.

Still, I agree with you. It's a very difficult target.

~~~
raldi
Where is that quote from?

It seems to me that the only way to hit the 90% target would be to include
270kg of dead-weight tungsten, and fit all the science into a 30kg budget.

~~~
schiffern
The relevant constraint isn't mass, but volume. Essentially you're limited you
to a cube 12 cm on a side (plus 1 cm³ for every 19.25 g of payload mass).

~~~
raldi
What are you basing that claim on? The quotes elsewhere in this thread seem to
contradict what you're saying.

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chton
My first thought for something actually doable would be a group of compressed
gas cannisters with highly reflective balloons attached to them. Very simple
mechanics, all you need is a strong valve on a timer, so it can be made to
survive the impact with the ground.

Once they're inflated, they would rise to relatively high up, so they can be
carried off by winds. Because of the high reflectivity, we would be able to
track them from orbiting imaging satellites and probably even from earth,
teaching us more about wind speeds and flows on Mars.

One thing I'm not sure about is if this could meet the weight/space
requirements.

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bd
ExoLance project is supposed to use that dead mass to shoot darts under the
Mars surface to look for signs of life:

[https://www.indiegogo.com/projects/exolance](https://www.indiegogo.com/projects/exolance)

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schiffern
Is that actually their plan? I haven't found anything about balancing mass on
their site.

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lawlessone
300kgs of gold. To encourage someone to come looking for it.

~~~
DCKing
The most expensive element you can currently send to Mars is platinum [1],
which would equate to a value of roughly €10 million. All other things you
could send either decay quickly (plutonium) or otherwise devalue over time
(micro sd cards) or fluctuate too heavily to depend upon (microSD cards filled
with Bitcoin private keys, LSD).

I wonder what would happen if a space agency went to Mars and dropped a minted
coin valued €50 billion (or something) by the US Treasury/European Central
Bank/National Bank of China and see who could retrieve it the quickest. That
should be an interesting competition.

[1]: [http://what-if.xkcd.com/108/](http://what-if.xkcd.com/108/)

(Edited because for wrong terminology)

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maggit
> The most expensive rare earth element you can currently send to Mars is
> platinum (...)

> All other things you could send either decay quickly (platinum) (...)

I don't understand. Did you mean platinum in both places? In that case, I got
confused by the "other". Or did you mean something other than platinum in one
of the cases? Or am I just failing to comprehend? :)

~~~
jobu
Based on the xkcd link I'm sure he meant plutonium decays quickly.

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readerrrr
Shape it into a kinetic projectile. With the orbital velocity it should make a
crater exposing underground materials.

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dannytipple
A solid lump of duct tape. Guaranteed to be useful in future.

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adnam
300kg of fireworks would make one heck of a display

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hammock
Need atmosphere to combust though

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azernik
No, most fireworks carry their own oxidizer. Otherwise even in Earth's
atmosphere their power would be quite limited by airflow.

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abakker
is there any logic to bringing some fissile material to mars for use as a
future fuel source? My gut instinct says no, but its among the only things I
can think of that would be heavy enough. Uranium and Plutonium are pretty
heavy.

The only other things I could think of would be common catalyst materials like
platinum. Something that could be collected and used later by some future
mission. Lead might be useful, as a battery component, but forming it would be
problematic.

If it remains tungsten, and the impact is going to be at very very high
speeds, do any of the other mars rovers have instruments capable of detecting
the seismic waves produced? Could that provide us any details of the makeup of
the crust? A 150kg tungsten mass would likely make quite a crater traveling at
9000MPH.

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javajosh
Better still: figure out a way to land without needing 300kg of dead weight.

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jackgavigan
Bottle-sized greenhouses.

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rtkwe
A lot of care is put into making sure we don't track Earth microbes to Mars in
the first place to make sure if we do find life we'll be pretty sure it's not
just a hitchhiker flown in from Earth in the last 40 years of space
exploration.

~~~
bostonpete
That's historically been true, but won't always be the case. NASA has talked
about putting humans on Mars within a couple of decades. It may be sensible to
try putting other living things on Mars in advance of humanity...

~~~
JoeAltmaier
This! Having supplies/environment primed and ready when humans arrive could
make the difference between a thriving colony and a miserable death.

~~~
rtkwe
The first colonies won't get any help from microbes on the surface of Mars,
it's too cold and dry for much of anything useful from Earth to survive much
less thrive. And the timescales for anything that could a) thrive and b) have
a measurable impact on the lives of colonist are way longer than (I hope) any
mission will land since it'd take decades/centuries for there to be a useful
impact. Eventually yeah introducing life to Mars will be a useful prospect but
we're talking about kickstarting a whole planet's ecosystem not something to
do haphazardly or that will show large impacts in a single lifetime.

~~~
JoeAltmaier
All we'd need is a bubble-greenhouse to be growing some wheat or something -
don't have to terraform the entire place.

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VLM
Why isn't this just given to amsat.org for a nice RF transponder? Could be the
location is non-optimal for solar / antennas, but ...

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InclinedPlane
These aren't going into orbit, these will be ejected during entry and landing.
They will end up on the surface of Mars and they won't have the benefit of
parachutes or rockets (unless you bring your own) slowing them down before
they hit the ground. That's a very demanding proposition to expect any sort of
system to survive, which is why it hasn't been done before and why this is
being set up as an open challenge now. Maybe someone will come up with an
intriguing possibility here that nobody else thought of, rest assured there
are no widely obvious, easy answers to the problem as yet.

~~~
VLM
google for the amsat suitsat program, its remarkably similar other than re-
entering earth instead of mars and being obsolete space suits rather than
counterweights.

I'm well aware there are subtle technical differences but the mission profile
isn't all that different. It would be an interesting place to start.

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ck2
Railgun.

Use the momentum just before it goes into orbit to blast it into deep space
with a message.

It could outpace Voyager easily.

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twosheep
Wouldn't the subsequent recoil push the MSL wayyyy off course?

~~~
rtkwe
Well, they /could/ factor the recoil into their insertion burn calculations.
That's just a matter of the repeatability of the railgun's acceleration.

Of course the better way to outpace Voyager at this point is probably an ion
engine, Voyager is sailing along at 17 km/s and the highest number I could
find for a current railgun is 2.4-3 km/s (and these way waaay more than
300kg), that leaves the orbiter with >14km/s of the velocity required to beat
Voyager. Each mission will come in at different orbital velocities but I found
that Odyssey had a velocity of "5.907 kilometers per second" [1] before it's
orbital insertion burn. Missions are more inclined to come in at or around
their final orbital velocity (getting there faster requires more fuel for
braking into orbit and more weight dedicated to that fuel requiring more fuel
[repeat until your entire launch weight is fuel with a postage stamp as your
probe]).

[1]
[http://mars.jpl.nasa.gov/odyssey/mission/timeline/mtmoi/moid...](http://mars.jpl.nasa.gov/odyssey/mission/timeline/mtmoi/moidescription/)

