The NASA Night Rover Challenge

[Lock]

http://nightrover.org/

$1,500,000

Awarded to the entrepreneur(s) who can create the best energy storage system that will allow a lunar rover to operate continuously throughout multiple lunar cycles including 14 straight days of sheer darkness.
* We are planning to announce final rules and open registration at the end of March.

night_rover_challenge_-_rules_-_final_public_comment_draft.pdf
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SECTION 1: OVERVIEW
The objective of the Night Rover Challenge is to foster innovations in energy storage technology.
Specifically, this challenge asks teams to create an energy storage system that can provide the power required for a lunar rover to remain continuously operational throughout 3 lunar cycles.

The energy storage system must meet these requirements:
 Have a mass of no more than 100 kilograms (kg).
 Be able to receive 120 volts dc with a current of 2 amps,
 Deliver power to a breakout box meeting a power draw profile (an average draw of 90 watts (w) during simulated lunar night time and 85w during daytime) throughout lunar cycle.
 Meet or exceed this power draw throughout 3 complete lunar cycles.

Three levels of awards will be possible:
1. Level 1: achieve greater than 300 wh/kg - (1st place $125K; 2nd place $50K; 3rd place $25K)
2. Level 2: achieve greater than 400 wh/kg - (1st place $350K; 2nd place $100K; 3rd place $50K)
3. Level 3: achieve greater than 500 wh/kg - (1st place $1,000K; 2nd place $300K; 3rd place $200K)

Lower level awards will ONLY be available if no teams reach a higher level. If one team achieves greater than 300 wh/kg, only 1st, 2nd, and 3rd place for Level 3 qualified teams will be available. If no teams achieve Level 3, then level 2 awards will be provided to eligible 1st, 2nd, and 3rd places for that level. If no teams achieve Level 2, then 1st, 2nd, and 3rd place awards will be available for eligible teams in Level 1.

In the event that more than one team meets the requirements for their level, the team with the highest specific energy (watt-hrs/kg) throughout the trials will be the first place winner, followed by the second and third highest in order.

The final interpretation of all rules is at the discretion of the judges. All amendments to the rules will be posted for public comment at least two weeks prior to being finalized and no amendments will be made any later than two months prior to the competition trials.

[bigmoose]

Class 1, 3, 4, 5, 6, or 7 hazardous materials are prohibited.

How is a guy supposed to achieve something when you handcuff him?

[Lock]

Hazard Class Labels
•Class 1 - Explosives
•Class 2 - Gases
•Class 3 - Flammable Liquids
•Class 4 - Flammable Solids; Substances Liable to Spontaneous Combustion; Substances Which, in Contact with Water, Emit Flammable Gases
•Class 5 - Oxidizing Substances and Organic Peroxide
•Class 6 - Toxic and Infectious Substances
•Class 7 - Radioactive Materials
•Class 8 - Corrosives
•Class 9 - Miscellaneous Dangerous Goods

Maybe don't mention the Lipo is from HobbyKing

[bigmoose]

Maybe don't mention the Lipo is from HobbyKing

You were thinking the way I was, but made the effort to find the hazardous material list! Think LiPo goes under Class 9; so it may be in.

We need to encourage Amberwolf to team with methods; then the two could be set for life by winning this prize and be famous to boot. Then I could be their bench tech stooge in their new la-bor-a-tor-ie and you could write historical documentaries on how they achieved their success, starting with Amber's first build...

[salty9]

I think that unless someone discovers a new physics law that only radioactives would meet their criteria.

[thewmatusmoloki]

I vote for wind power.


Just look at that flag in the moon landings, it's gotta be windy as, up there !

[amberwolf]

Why bother with an advanced energy storage system at all? It would have to be capable of a MINIMUM of 32KWh just to deal with the ~354-hour Lunar night, assuming 90W average draw. That's pretty big, even at 500Wh/kg, considering we'd have to launch that mass from Earth's surface, when instead it could be made lighter *or* carry more useful instruments, more powerful motors, or whatever. It would be a minimum of 64kg of battery (assuming 100% DOD!), and that does not include support systems necessary to charge that battery at a high enough rate so that it would fill up the battery with available (solar?) incoming power during the ~354-hour Lunar day.

Personally I'd assume 50% DOD, so we could be sure that degradation over time would still leave it with enough capacity to always last the night cycle even as it ages, and also have no worries about damaging the battery by overdischarge. That means at least 128kg of battery.

Since they want *3 Lunar cycles* (presumably 3 synodic periods, or 2125 hours and some change) worth of battery, that's at least 384kg of battery. During Apollo, we barely brought back that much mass *from* the moon, AFAIK.

That is almost 850 pounds of batteries! Even if you had a battery that could deal with 100% DOD and thus could use half of that, 425 pounds of batteries is a whole lot of weight and size that you don't really need, because there is a better way.

EDIT: I messed up the above 3-cycle calculation. It is actually TWICE that, since 3-cycles includes daytime running as well (although it would need only about 8/9 of the power during the day since it doesn't have to run heaters, presumably). So that is 768kg of battery, for 50% DOD, or 1700lbs of batteries. The 384kg/850lbs is only for 100% DOD!

AFAICS, there is no way to actually achieve what they want unless the energy density is much higher than 500Wh/kg. They want 100kg or less pack, but capable of at least 192KWh (for 3 full day/night cycles). That is close to 2000Wh/kg unless I messed up the math badly. And that's assuming 100% DOD!

Hopefully I messed up somewhere else, too because these numbers seem pretty impossible to get around.



That's assuming 500Wh/kg. You can do the math if that can't be reached, for the other power densities. And for what mass battery you would need if you used existing proven technology.

Oh--one more thing: Whatever is used needs to be "safe" in the case of system or power failure that causes heating or cooling problems. It gets nice and toasty in the day, and danged cold at night, and each of those stay that way for most of their respective cycle halves, of 354 hours. At the equator, that could be below -279F, or above 242F!


And 500Wh/kg (and especially 2000Wh/kg!) is probably unattainable right now, anyway, or if it is attainable will cost WAY too much money. Even for NASA.



For that money, I would bet you could stick a solar powered microwave station in both Lunar L4 and L5, and install a rectenna system on the many rovers, bases, orbital spacecraft, etc. that they can power. No atmosphere to spread the beams or lose power, so if they can be focused well enough you could beam a lot of power to any of these things.

If there are areas to be explored that could be out of LOS of a station's orbital loop, "mirror" stations could be placed in Lunar orbit so that periodically they would overfly the area with an intersection path; if the mirror cannot be done directly it could be done with a receiver/retransmitter. Such stations could also have radio relays on them for data streams, as well as other instrumentation packages for use when they are not receiving a microwave beam (I assume that would interfere with various RF-based instruments and communications, at those power levels).

Tracking the beams to the rovers with the time-delay of light at that distance might be an issue, but not unsolveable, since we would easily be able to predict or program the path of the rovers. Manned craft on the surface might be less predictable if manually controlled, but orbital craft would all be perfectly predictable in all normal circumstances.


I don't know if it is more or less efficient to convert from solar to microwave, receive microwave and convert to electrical energy, use it as it's received, and also store some of it as needed to top off batteries, than it would be to have the solar directly on the rover to charge the batteries, and to carry enough battery to last *at least* two weeks at 90W average draw. But I expect teh rectennas and smaller batteries would enable a smaller rover or at least a lighter one, making it easier for it to traverse rougher terrain (of which there is a lot! ) and to go up hills and thru that fine dust with less power usage.


Dunno what they use for storage on things like the Mars rovers, but that could be used as backup storage on the Lunar rovers, for times when they might go out of LOS of a station or "mirror" station, or the short periods when the L4/5 stations are in Lunar or Earth shadow, unable to provide power.




Doesn't help with this actual challenge, but that's what I would probably do to help power Lunar exploration/exploitation missions, becuase these stations would be permanent installations, and able to beam power anywhere in the Earth/Luna system other than the opposite sides of either body from the stations. A station at Lunar L3 would fix the Earth shadow, and L2 the narrow Farside shadow zone. Not sure what to fix polar shadow zones with, other than polar-orbiting "mirror" units.

[Arlo1]

Maybe we can argue lipo will be safe with out oxygen? Yup its class 9 on earth but once out of our atmosphere it it non flammable

[amberwolf]

Even the best of existing batteries simply will not do what they want it to do. RC LiPo or similar won't even come close.

[thewmatusmoloki]

But seriously folks, why not use the energy that already exists there.

Vacuum.

What about some kind of compressed gas, I dunno about gasses, argon maybe, up there in the lightest container that can be made (carbon fibre? or just a balloon in a pressurised evironment)
then a slow release to power a couple of tiny, but efficient generator's. It might last long enough to get the mission done.

[amberwolf]

You would want to use cryogenic hydrogen, to get the greatest pressure differential for the lowest mass, I would think.

How much gas mass are you going to need, and how far are you going to be able to compress it, with a small thin-walled lightweight tank that has to survive the stresses of launch?

You'd also have to use some of the power (maybe a lot) to keep the hydrogen cold, since the vehicle's electronics will emit a fair bit of heat (which is probably why there is only a 10W difference expected between night and day in power usage). Although you could use it to cool some of the electronics, like the radio transmitters, and gain pressure differential, on the exit tubing from the tanks into the generators.

The gas will also be contaminating the environment around the rover, continuously, so all your sampling and analysis instruments will ahve to be designed to work around that.

[thewmatusmoloki]

bummer

[Kingfish]

I have a spreadsheet of parameters and properties of LiPo RC packs from HK ranging from 3S to 8S with Ah from 3.6 to 5.8. Twiddled about with the figures, the best Wh/kg ratio is 181.7 for the Zippy FlightMax 5S 15/2C (which coincidentally is the RC battery that I use… though I bet you might have guessed that ). I don't know of a more compact & reasonably-priced LiPo system.

• Does the hazardous material specification rule out Fuel Cells & Hydrogen?
• Perhaps a little Muon-catalyzed fusion is in order
• Better yet, forget about taking fuel with you – other than for system startup: Use the materials at the landing site, e.g. Water-Ice ... If yer always in shadow, that's one-half of the thermal flux to have to deal with. The spec says "Rover", but what's to prevent the rover from fueling up?

What other surface lunar materials could be scavanged on-the-fly to provide fuel; opportunistic power generation? Can we use raw materials to construct one-part of a battery?

Thinking outside my cage, er… the box, KF

[Hillhater]

If it were as simple as using a big pack of lipo, or a hydrogen cell, or solar panels , etc etc, ..... they would not have bothered with this challenge and offered $1.5 m for a solution.
they are "milking" the community for ideas to solve a problem they cannot !
$1.5m will be a really cheap solution to a huge problem !

[Arlo1]

Yeh I realize that. We are all just kidding about HK lipo. It will need to be some out of the box thinking there. Or a new chemistry. Lithium air or water???

[amberwolf]

That's why I went not only out of the box, but left the entire warehouse for what I proposed.

[liveforphysics]

Magnesium foil anode. Sulfur cathode. Minimal conductive additives (because C-rate is <1/100), thin current collector foils and thick coatings.

The missing link is an electrolyte that works, but those materials paired up are capable of >700wh/Kg.

You could alternately use a lithium metal foil anode, but that might be considered an outlawed material, and the dendrite growth is random, so you couldn't guaranty it wouldn't all explode on the first charge cycle, unlike the Mg which doesn't form dendrites and plates evenly.

[flathill]

This one is easy
A mechanical battery using carbon nanotube springs
http://en.wikipedia.org/wiki/Carbon_nanotube_springs

A middle eastern country has already had this tech according to some guy I met at techshop
It winds up using a magnetic field

[flathill]

Magnesium foil anode. Sulfur cathode. Minimal conductive additives (because C-rate is <1/100), thin current collector foils and thick coatings.

The missing link is an electrolyte that works, but those materials paired up are capable of >700wh/Kg.

Might be the missing link http://www.pelliontech.com/pdfs/Pellion ... _Final.pdf

Aurbach is their sci adviser and they have several classes of electrolytes

[Josh K.]

I will give a talk to Ms Amy Prieto, from CSU. They have a Nanotech lithium battery that they claim has around 1,000 times
the energy density of traditional lithium ion cells, using safe materials. Orange juice is part of the equation...

I hear that some of the cell packets have been tested to over 800 cycles now. Must be nice to harness grad students for research,

Josh K.

[hydro-one]

superconducting coil ?? seems easy enough with some aerogel insulation, plus isnt the moon cold?