NXT and Lunar X PRIZE
Okay, here's a little thought experiment. Ignoring getting the robot to the moon (the rocket side of the equation), what would it take to get an NXT robot to win the Lunar X PRIZE?
Here is the contest objective described in the simplest terms (taken from the official website):
"To win the Google Lunar X PRIZE, a team must successfully land a privately funded craft on the lunar surface and survive long enough to complete the mission goals of roaming about the lunar surface for at least 500 meters and sending a defined data package, called a “Mooncast”, back to Earth."
So, a few things:
From Ask an Astronomer: The temperature on the moon varies from -387 Fahrenheit (-233 Celsius), at night, to 253 Fahrenheit (123 Celsius) during the day. Because the moon has no atmosphere to block some of the sun's rays or to help trap heat at night, its temperature varies greatly between day and night.
This leads to some questions:
1. At what temp will plastic (specifically, LEGO NXT Technic plastic) shatter?
2. At what temp will rubber shatter?
3. Can the NXT Brick be insulated somehow to protect it from these temps? Does circuitry degrade at these temps?
I think most of us will agree that sending an NXT robot to the Moon's surface is probably a bad idea. But there's a saying that I'm going to modify a bit - "The only difference between the difficult and the impossible is cost."
So, given some funding, how would a dedicated group of LEGO NXT fans go about building a robot that is NXT based that could participate in the Lunar X PRIZE? Cast components out of metal? Insulate the Brick inside some sort of shell?
(Don't take this too seriously, folks... have fun with it and keep the discussion positive)
Here is the contest objective described in the simplest terms (taken from the official website):
"To win the Google Lunar X PRIZE, a team must successfully land a privately funded craft on the lunar surface and survive long enough to complete the mission goals of roaming about the lunar surface for at least 500 meters and sending a defined data package, called a “Mooncast”, back to Earth."
So, a few things:
From Ask an Astronomer: The temperature on the moon varies from -387 Fahrenheit (-233 Celsius), at night, to 253 Fahrenheit (123 Celsius) during the day. Because the moon has no atmosphere to block some of the sun's rays or to help trap heat at night, its temperature varies greatly between day and night.
This leads to some questions:
1. At what temp will plastic (specifically, LEGO NXT Technic plastic) shatter?
2. At what temp will rubber shatter?
3. Can the NXT Brick be insulated somehow to protect it from these temps? Does circuitry degrade at these temps?
I think most of us will agree that sending an NXT robot to the Moon's surface is probably a bad idea. But there's a saying that I'm going to modify a bit - "The only difference between the difficult and the impossible is cost."
So, given some funding, how would a dedicated group of LEGO NXT fans go about building a robot that is NXT based that could participate in the Lunar X PRIZE? Cast components out of metal? Insulate the Brick inside some sort of shell?
(Don't take this too seriously, folks... have fun with it and keep the discussion positive)
Comments
So I think that a moonbot would need a heat source to keep its batteries functioning in extreme cold.
"Bang Zoom!"
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Brian Davis
But really, would putting a wool cap over the back of a camcorder make it last much longer in extreme cold temperatures? (i.e. single digits, Fahrenheit) My son was using it on a tripod. Perhaps it might have lasted longer if someone was holding the camera while filming.
Examining present "robots" might help. Both the lunar rover (ok, it's not a "robot" but it's electrics/tires/etc had to endure the moon) and the mars rovers (not quite as harsh an environment) could provide clues on what'd be needed.
Metal wheels are a must.
Moon dust was a real issue...so airtight seals around the motors would be necessary.
If the mars rover has to use a heater to keep it's electrics from freezing, that'd probably need to be standard equip for an NXT rover as well.
Also, since the moon rotates so slowly, and the robot only has to go 500 meters couldn't it just be landed on the near side to perform it's tests? This would eliminate some of the need for insulation due to cold, no? Or vice-versa?
No, the ABS couldn't cut it as far as the thermal issues go. It has a rather narrow range of temperatures that it can handle, while the range on the lunar surface is huge. Even the Apollo missions landed near lunar "dawn", so that the temperatures of the rock surfaces were moderate, and yet they still had to contend with plastic-shattering cold in the shade, and plastic-melting heat in the "morning sun".
But in that case, take out the ABS... the electronics in the NXT alone are a significant improvement in terms of processing power, speed, memory, and power consumption, to the entire Apollo CSM. The problem here might be they are not radiation-resistant (Apollo memory, based on ferromagnetic cores or "donuts", was). Still, you might get around this by using several and "voting out" the proper result. So that *might* be doable.
DC motors are, well, DC motors - they should function fine in a vacuum (at least for a short time or at low power... again the thermal management issues get tricky). Lunar dust probably isn't a huge worry - yes, it will eat the motors, but if you make sure the motors are near the front, ahead of any wheels, and you only drive forward, then the front stays fairly dust-free (no air means no billowing dust... just ballistic dust).
Batteries are an issue - yes, they need to be warmish to work, and unless you keep them warm the entire cruise phase, you've got a big problem at the end. But you might reasonably manage a short surface stay using banked capacitors as a power source, charged from the delivery vehicle just before landing (hey, if Jim says I don't need to worry about the rocket, I'll let the same folks who are building the rocket build my custom cruise stage ;) ).
Sensors, well... the US sensor & sound sensor are clearly out, and the light sensor might be close to useless (talk about a place with shadow issues...). The touch sensor would work fine... but if it's based on resistance, temperature swings are perhaps a very critical problem (& sensor tend to be exposed, not in the warm electronics box). Possibly mechanical touch mechanisms that move something over a fiber-optic transmission to a light sensor internal to the WEB might work, and the Hitechnic gyro & accelerometer would be critical (they can function inside the WEB as well), but the compass would be pointless. Hmm...
This is a fun little problem, how to take the NXT to the Moon. Literally :)
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Brian Davis
Lunar X Prize:
To add some to what Brian has already said about electronics heat..
Many of the Space Shuttle's avionics boxes are attached to 'cold plates' to maintain a nice temp. Air-ducts flow chilled air directly to many units as well.
I remember a discussion we had back in the old MINDSTORMS forms that went on for years....about how the RCX would fair on a spacewalk.
Kirk has it... a space suit.
..or a pod. Though, an All-LEGO solution is possible in simulations. However, being a LEGO purist, I would like to send one to the Moon anyway.
Chris
With some modification almost anything is possible.