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Rover Design essentials

Posted by: Rocket Scientist - Sat Sep 22, 2007 10:21 pm
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Rover Design essentials 
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Space Walker
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Post Rover Design essentials   Posted on: Sat Sep 22, 2007 10:21 pm
I thought we could start a list of essential components for the lunar rover.

Video camera
Digital camera
Receiver
Transmitter
Batteries
Solar cells
wheel drive motors

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Post    Posted on: Sat Sep 22, 2007 11:10 pm
What about heaters and dust filters?

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Post    Posted on: Sat Sep 22, 2007 11:14 pm
Klaus Schmidt wrote:
What about heaters and dust filters?

Sure. My original list is by no means meant to be an exhasutive list. I was hoping others would add to it. I'm currently reseaching the lunar environment to get an idea what a lunar rover must deal with in terms of temperature and radiation. I'm using the Sojourer rover as a starting design point. I believe mimimizing the weight of the lunar rover will be important.

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Last edited by Rocket Scientist on Sat Sep 22, 2007 11:23 pm, edited 1 time in total.



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Post    Posted on: Sat Sep 22, 2007 11:20 pm
Rocket Scientist wrote:
Sure. My original list is by no means meant to be an exhasutive list.


So I understood it ;), but I'm not sure about dust covers for example. Is the lunar dust a problem for short duration operation?

What is missing I think is some kind of radiation-hardened microprocessor.

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Post    Posted on: Sat Sep 22, 2007 11:43 pm
Klaus Schmidt wrote:

So I understood it ;), but I'm not sure about dust covers for example. Is the lunar dust a problem for short duration operation?

What is missing I think is some kind of radiation-hardened microprocessor.


There are COTS space rated microprocessors on the market.

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Post    Posted on: Sun Sep 23, 2007 2:56 am
You only need one camera. A modern digital camera is both a video and a still camera.

Heaters would not be needed in the day time. Overheating will be a bigger problem than being cold. I doubt anyone will attempt to make a rover than can operate through a 2 week long lunar night, at least not for this competition.

You will need a high gain antenna, which would be directional, requiring a mechanism to point it at Earth. This may be the biggest problem, after getting to and softly landing on the Moon.

You will need a steering mechanism.

It may be possible to do without a computer, just using ordinary radio control to directly commanded it in real time from Earth, like a toy car. It will be tricky to operate though since it probably will not have enough downlink bandwidth to give full motion real time video while driving.


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Post    Posted on: Sun Sep 23, 2007 7:04 am
campbelp2002 wrote:

You will need a steering mechanism.

It may be possible to do without a computer, just using ordinary radio control to directly commanded it in real time from Earth, like a toy car. It will be tricky to operate though since it probably will not have enough downlink bandwidth to give full motion real time video while driving.


The steering mechanism is probably easiest to do like tanks to dit. Also saves some room for servo's etc. The computer should be helpfull, but would it give that much more advantage in contrast to the complexity and thus possible added problems?

I think the list should be made as short as possible. Think of it as a race (which it is). If you could win with a Skoda, why buy (or built) a luxuries Mercedes?


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Post    Posted on: Sun Sep 23, 2007 7:31 am
G'day,

Mars pathfinder only gave the rover a small relay radio. The main antenna
and communication equipment was left on the lander. Same system can be used here.

ta

Ralph


campbelp2002 wrote:

You will need a high gain antenna, which would be directional, requiring a mechanism to point it at Earth. This may be the biggest problem, after getting to and softly landing on the Moon.

.


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Post    Posted on: Mon Sep 24, 2007 9:48 am
What about a look into financial constraints helping to find the maximum possible?

From another thread of this section it seems that a Falcon 1 could be sufficient. The launch of a Falcon 1 costs $ 7 mio at present. Subtraction of 10% reduces it to $ 6.3 mio while future accounting for reusability the price might drop by a few millions.

The 10% reduction on $ 7 mio could be taken as financial ressource of $ 700,000 - these Dollars can be used to pay for parts, devlopment, construction etc. If there are ressources beyond those $ 700,000 they could be added.

So it is possible to look what you can get bought, devloped and constructed for $ 700,000 + while keeping it within the payload capacity of a Falcon 1.

If the weight exceeds that capacity a Falcon 9 can be considered. The launch costs $ 35 mio at present - minus 10% is giving $ 31.5 mio. So then $ 3.5 mio would be left from the original full price for parts, development and construction.

What could be added to the list taking this into account?

Another constraint could be the amount someone wnats to be left from the prize after subtraction of all costs and investments.

(Just this moment I become aware that the Falcon 9 launch-price alone would mean a loss even if the prize is won - this idea requires a price taking into account reusability.)



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Post    Posted on: Wed Sep 26, 2007 9:40 am
Regarding the solar cells - which quality should they have? How much do consider to be required? Should the sunlight be concentrated by lenses to keep the number of solar cells small? What about protection against increased degradation in space?

One or the other of these question may be of meaning for what can be achieved or for ideas like landing the rover close to an Apollo DS and examining it.

What about tracks instead of wheels or even legs? Might be an interesting innovation perhaps.

...



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Post    Posted on: Wed Sep 26, 2007 3:59 pm
ralphbuttigieg wrote:
Mars pathfinder only gave the rover a small relay radio. The main antenna
and communication equipment was left on the lander. Same system can be used here.
Of course that limits the range of the rover to areas with a line of sight to the lander. The prize requires the rover go at least 500 meters. The Mars Pathfinder rover never went anywhere near that far. It is very unlikely that a small, low to the ground rover could guarantee to always maintain a line of sight 500 meters back to a lander on the rolling, uneven lunar surface. And just forget about it for the 5 km bonus prize! I am not a radio engineer, but maybe a high enough gain antenna could be made small and light enough to be carried on the rover and kept pointed at Earth well enough as it moved. Only a very low data rate is needed for control, so pointing is not as critical to maintain control as it drives, and after it stopped it could fine tune the antenna pointing for the high data rate needed to send images. Some kind of simple computer would be needed to control the antenna pointing.


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Post    Posted on: Wed Sep 26, 2007 5:09 pm
Because of the lack of an atmosphere to diffuse the sunlight, I think that a solar panel would produce more power than it would on Earth which would result in a further weight saving as smaller panels could be used.

Anyone know what the difference is between the effective light levels at Earth and the moon is?

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Post    Posted on: Wed Sep 26, 2007 6:45 pm
This source:
http://marine.rutgers.edu/mrs/education ... i/erb.html
says that 6% of incoming solar energy is reflected by the air and 16% is absorbed by the air. Clouds are not included in that, so on a clear day a solar panel on Earth gets 22% less power than one in space, or on the Moon.


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Post    Posted on: Thu Sep 27, 2007 7:42 pm
Ekkehard Augustin wrote:
Regarding the solar cells - which quality should they have? How much do consider to be required? Should the sunlight be concentrated by lenses to keep the number of solar cells small? What about protection against increased degradation in space?

One or the other of these question may be of meaning for what can be achieved or for ideas like landing the rover close to an Apollo DS and examining it.

What about tracks instead of wheels or even legs? Might be an interesting innovation perhaps.

...
Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

Spectrolab manufactures space rated solar cells and solar panels. My company uses them for our solar panel arrays that go on our satellites.

http://www.spectrolab.com/

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Post    Posted on: Thu Sep 27, 2007 8:17 pm
In my recent research I wanted to explore past lunar rovers. The first lunar rover was the Russian Lunokhod 1 in 1970.

http://en.wikipedia.org/wiki/Lunokhod_1

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