
NASA Revives Plan to Put Nuclear Reactors on Mars - curtis
https://www.nbcnews.com/mach/science/nasa-revives-plan-put-nuclear-reactors-mars-ncna778536
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Cumulonimbus
Before we can consider seeding terrestrial stations on Mars, we should
consider seeding a communications net around Mars. Once we have a half dozen
satellites circling Mars, we can start stable comms from the surface to orbit
to Earth. It may take 10-20 minutes (for a signal to be received), but the
communication is the essential piece here.

I'd also consider putting satellites in Earth and Mars lagrange L3, L4, and
L5. It's the start of a solar system based internet, even if it is
rudimentary. Think of this as a store-and-forward network where signals may be
too weak for Earth to pick up, but can hit Jupiter L5 to Mars planet, to Earth
L3.

And greetings, all, BTW.

~~~
Robotbeat
> Before we can consider seeding terrestrial stations on Mars, we should
> consider seeding a communications net around Mars.

We already do.

> Once we have a half dozen satellites circling Mars...

We already have half a dozen active satellites circling Mars:

[https://en.wikipedia.org/wiki/2001_Mars_Odyssey](https://en.wikipedia.org/wiki/2001_Mars_Odyssey)

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

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

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

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

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

All of these (including the European satellites) except the Indian MOM orbiter
contain a communications relay radio (for relaying from Mars surface to Earth)
provided by NASA:
[https://en.wikipedia.org/wiki/Electra_(radio)](https://en.wikipedia.org/wiki/Electra_\(radio\))

We actually have quite a bit of infrastructure built up around Mars already.
All these spacecraft are referred to as the "Mars fleet" (which is frakking
awesome...).

~~~
FLUX-YOU
>[https://en.wikipedia.org/wiki/Electra_(radio)](https://en.wikipedia.org/wiki/Electra_\(radio\))

>Data rates up to 1 Mbit/s

That's a bit of a problem. It only seems to be a relay for other spacecraft
and small surface craft. Much more data will need to be exchanged between
Earth/Mars when humans are involved (weather, video, entertainment, collected
data, software, etc.)

You'd probably want several brand new satellites dedicated to communications
for an initial colonial undertaking.

~~~
trey-jones
If you think about the initial communications infrastructure around North
America when Columbus set sail in the 15th century, we've got a leg up.

I realize it's not the same situation, not the same expectations, a different
world than 500+ years ago, but real progress doesn't happen in a cleanroom.

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sp0ck
It's about time. Engineering decisions shouldn't be made based of irrational
fears of general population. If nuclear power plant is best option for space
mission we should use it.

~~~
MichaelMoser123
Irrational fears? What are the chances of the rocket launcher blowing up with
the reactor? How would we compute the fallout range as a function of altitude
of the blast?

~~~
DennisP
Irrational because a uranium fission reactor contains very little
radioactivity before you start running it.

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davedx
I looked into some numbers on this, comparing theoretical costs of nuclear
power with a solar PV solution on Mars.

Kilopower (NASA's research project for a Martian nuclear fission reactor, from
the article): 7,200 kg for 40 kW. [1]

ISS solar arrays: 14,515 kg for ~100 kW in Earth orbit. [2] If we assume
40-50% Earth solar insolation on Martian surface, the ISS PV array probably
isn't far off 40 kW output on Mars

Conclusions:

Nuclear reactor would have approx. 50% launch weight. SpaceX estimate $45/kg
payload with a Falcon Heavy, so about $324K for Kilopower or ~$600K for the
ISS arrays.

The build cost of the ISS arrays was around $300 million (space PV is way more
expensive than terrestrial). The development and test costs of Kilopower is
around $15 million; build cost of final units is unknown.

You would have to automate and/or remotely control all of the nuclear power
plant operations. Dust storms would be a challenge to a PV solution, though
not insurmountable.

They actually look very comparable. Nuclear has an edge due to it weighing
half as much as the equivalent PV generation system. I think there is
definitely value to a simpler system that's more decentralized... but that's
harder to quantify.

Edit: people noted I forgot to factor in batteries. 40 kW = 480 kWh per 12
hours. 1 Tesla PowerPack = 220 kWh @ 50 kW. Let's assume a worst case that the
base needs the same electrical power during the night as it does in the day,
so we need around 5 PowerPacks to get us through each night. 1 PowerPack
weighs 1,622 kg, 5 = 8,110 kg. Wow, we need another Falcon Heavy trip just to
bring us enough batteries for 1 night! Let's not mention those dust storms
that can last for a month or so...

Now nuclear looks much better... and that has its own complexities. Colonising
Mars is going to be very hard. :)

[1]
[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201600...](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160012354.pdf)

[2]
[https://www.nasa.gov/mission_pages/station/structure/element...](https://www.nasa.gov/mission_pages/station/structure/elements/solar_arrays.html)

~~~
aphextron
>The build cost of the ISS arrays was around $300 million (space PV is way
more expensive than terrestrial).

That was 20 years ago, on a government contract, for panels that must survive
the rigors of _actual_ space.

Panel manufacturing costs have dropped almost 10x since then, and the
environment (assumed under the protection of martian atmosphere) which they
will operate will be far less extreme than Earth orbit, necessitating less
expensive materials. I'm not so sure your numbers account for this.

~~~
Kubuxu
Space applications use single crystal GaAs (Gallium arsenide) process instead
of wide spread c-Si (Crystalline silicon, currently usually multi-Si), due to
their superior performance and weight.

Process of producing c-Si panels has become a lot cheaper but this doesn't
apply to GaAs process.

~~~
philipkglass
The International Space Station's solar array is crystalline silicon:

[https://www.nasa.gov/mission_pages/station/structure/element...](https://www.nasa.gov/mission_pages/station/structure/elements/solar_arrays.html#.WV0s5dPytE4)

Space applications are now mostly using triple-junction cells with GaAs as one
of the layers. Spectrolab, Azur Space, and SolAero's product lines are
dominated by triple-junction cells. Azur Space also still sells space-
qualified silicon cells (lower efficiency and much lower radiation tolerance,
but cheaper):

[http://www.azurspace.com/images/pdfs/0002162-00-03_DB_SIA.pd...](http://www.azurspace.com/images/pdfs/0002162-00-03_DB_SIA.pdf)

The Martian radiation environment is mild enough that crystalline silicon
might still be competitive if you needed large stationary arrays. But on the
Martian surface, where you can't rely on near-constant sunlight, nuclear is
going to be tough to beat. (Orbiters are a much better match with solar.)

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legulere
How will they convert heat into electricity? On earth you have plenty of water
as a good medium for the heat and a thick atmosphere that serves as the
heatsink. On mars you have neither.

~~~
dredmorbius
Sterling-cycle generator, utilising heat pipes, based on this study (PDF):

[http://permalink.lanl.gov/object/tr?what=info:lanl-
repo/lare...](http://permalink.lanl.gov/object/tr?what=info:lanl-
repo/lareport/LA-UR-14-23402)

Tracked via Wikipedia, which has a brief article:

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

~~~
jwilk
Non-mobile link:

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

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DanielBMarkham
There are a few obvious things that need to be stated in order for the public
to prepare for a manned Mars mission.

The fact that we're going to have to use some sort of atomic batteries is one
of them. Another is that we can't search the entire planet for life before we
go visit. It's impossible to disprove a negative.

My preference would be to see every piece of gear have an integrated solid-
state nuclear battery and O2/H2O generator. That way we design one cheap,
rugged, relatively low-weight and low-volume piece of gear and then just mass-
manufacture it. Also no astronaut would ever be far from water or air, and
there becomes a zero chance of death by asphyxiation or dehydration.

~~~
moovacha
It's easy to disprove a negative. Simply find life on Mars.

I think you meant, it's impossible to prove a negative. More specifically, to
prove that something does not exist.

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pheldagryph
Not a great headline; fission reactors have been critical part of the Mars
Design Reference Mission architecture for the last quarter-century. The news
seems to be that NASA is starting to test prototypes (which is definitely
still cool).

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

MDRM 5.0 PDF (big file; power generation is 7.3.4, page PDF-pg#85):
[https://www.nasa.gov/pdf/373665main_NASA-
SP-2009-566.pdf](https://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf)

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jasonrhaas
The best part about this article is this picture --
[https://media2.s-nbcnews.com/j/newscms/2017_26/2057221/snap_...](https://media2.s-nbcnews.com/j/newscms/2017_26/2057221/snap_post_card_2e783660691421a54fa05af239bc7af4.focal-678x886.jpg)

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notadoc
I'm strongly in favor of going to Mars, but maybe we should also work on
fixing up our home planet too.

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SCAQTony
Wouldn't the moon would be a better choice? Asteroids could be processed
there, it could be a de facto source of microwave power for asteroid mining
ops and a weigh station to bring metals back safely.

~~~
TomK32
The moon is boring, Mars once had water and very likely life on it. Moon has a
month-long day/night cycle and less gravity, two thing humans aren't well
adapted.

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Knufen
Anyone know what the projected cost of transport, setup, shielding and
maintenance etc. is?

~~~
zeofig
With existing and conceivable technology, I would project them as effectively
infinity. The whole thing is only good for PR.

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foota
Are there fissionable materials on Mars?

~~~
nradov
Sure there is uranium on Mars. But extracting and refining it won't be easy.

~~~
davedx
Probably cheaper to just put the fuel rods on the rocket with the reactor for
the foreseeable future...

~~~
xorfish
Enriched uranium has a very high energy density. 20% enriched Uranium would
contain 16TJ/kg.

So a 4MW u-battery would use around 8kg fuel per year.

~~~
baybal2
>Enriched uranium has a very high energy density. 20% enriched Uranium would
countain 16TJ/kg.

I did not count in burnup ratio. A simple thermal neutron reactor can only use
<1% of fission energy in its fuel.

~~~
xorfish
I'm pretty sure that conventional reactor split around as much fuel as the
U-235 content.

For conventional reactors it is around 3% and you are left with around 3%
fission products.

Natural uranium has around 0.7% U-235. But I0m pretty sure that you would
enrich the uranium befor you send it to mars. The 16TJ/kg is for enriched
uranium with 20% U-235 content.

Anyway, energy density of nuclear fuel is extremly high. Even if you pay 10000
USD/kg for the transport of fuel to mars, you'd pay around 1 cent/kwh for the
transport.

~~~
baybal2
Yes, it will be higher by few times for highly enriched uranium (90%+) or
plutonium 239 (because of higher cross-section)

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cortexio
I'm getting kinda sick of the media putting more & more non-sense in our heads
instead of actual news. This is pure fantasy. They can't build nuclear
reactors on Mars! The only reason why they write this article is because the
topic "Mars" generates large amounts of views. News shouldn't be a bussiness
:(

~~~
8draco8
Genuine question: If it's possible to use mini nuclear reactors in satellites
then why they just can't land that thing somehow on Mars (like they did with
Curiosity) and use it on planet surface to power lab?

~~~
cortexio
Mini reactors are useless on Mars. The power they generate is waaay to low
compared to the money that is needed to bring them there. Also putting nuclear
reactors on sattelites almost never happens and is VERY DANGEROUS. It's what
the Soviet Union did in the 70s-90s. The last sattelite launched with a
nuclear reactor was in 1988.

You have to be pretty insane to launch large amounts of nuclear material from
earth in a rocket that can randomly explode in our atmosphere.

~~~
valuearb
U-238 is pretty stable.

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vectorEQ
put a nuclear plant on your fregging moms house. the moon doesn't belong to
nasa so fuck off!

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Finnucane
Will no one think of the children?! I mean, specifically, NASA's hostage
martian slave children. Will the reactors be made half-scale, so they can be
operated by the children's tiny hands? Will the children be forced to labor in
the plutonium mines, far from OSHA oversight?

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timtosi
The last time I heard about humanity settling on Mars on behalf of an
Aerospace Corporation, it was about opening a gate to hell.

~~~
arkitaip
We just have to make sure that there's a Marine onboard. Or maybe a nuclear
scientist with a crowbar.

