Hypography X Prize Entry

[TheBigDog]

I had not considered the idea of building earth based communications systems. I figured we would latch onto some existing antenna system for space based communications. If it is not too much we could always build a series of stations in the yards of Hypo members around the globe to maintain 24x7 contact with the moon. Another aspect of the mission to contemplate, but I would make it a later requirement of the mission.

 

Bill

[Turtle]

I had not considered the idea of building earth based communications systems. I figured we would latch onto some existing antenna system for space based communications. ...

 

Back in post #66, GAHD posted this: >>

The Allen Telescope Array (ATA), operated by the SETI Institute, will serve as a preferred downlink provider for communications from the Moon to the Earth; operated by SETI, which will provide downlink services at no cost to competing teams;

 

Once the full rule set is out we will know better what we need.

 

A bit more on my motor-flywheel-wheel scheme. :doh: We can obviate the need for steering motors by using the trick the cheaper remote-control toys use, i.e. there is a pivot arm that works to turn the front wheels when the vehicle backs up. The wheels straighten when forward power is applied. We could also simply go in reverse to make a full circle and get our panorama shot without having the need for a motor to rotate the camera. (any motive force we want such as camera tilt or pan can be drawn from the flywheel too.)

 

That's all I got. :hihi: :doh:

 

PS I have acquired on loan an RC car and have a camera. What did we want to do with these again?

[Turtle]

PS I have acquired on loan an RC car and have a camera. What did we want to do with these again?

 

OK. The gears in the car are nylon and there is a high-low switch on the gear box, but short of building from scratch I see no way to "simply" re-gear the existing tranny. We might possibly control speed by using a rheostat on the motor circuit? More heat. :shrug:

 

I put my 9 pound stone mortor on the car to simulate our 5 kilo mark and it drained the battery in short order with little headway forward and wouldn't drive in reverse or steer. (the car weighs about 2.5 pounds) I have one Ni-Cad and one Nickel-metal hydride 9.6 volt battery.

 

The red-headed neighbor kid suggested putting the camera on an articulaterd arm like the shuttle's Canada arm and also having the lander provide an enclosed garage for the rovers. Not sure about the arm (although it would accomplish the self-portrait requirement), but the garage idea might be the key to surviving the 2 week night for the $5 million bonus.

 

Having way too much fun,

Tortuga :)

[Janus]

I see this mission in three distinct steps - though smaller substeps will probably become apparent, but never-the-less, three main steps

 

1. Get to LEO

 

delta V of LEO is ~7.8km/s plus drag ~9-10km/s

 

This is what will be required of the launch system - I am currently looking at what Boeing have to offer and am wondering what the mass of our LEO and beyond module will approx weigh? then a suitable rocket can be selected and we can get a ball park price.

 

2. LEO to lunar (orbit?) or straight towards the surface..

 

delta V required is 4.1km/s to the lunar orbit, or 5.7km/s to the Moons orbit

Not sure how this part will be powered but I would like to know approx % of total mass that is required to get us this part of the trip (this may depend on the fuel used?)

 

3. Deceleration

 

now what happens for here? do we require a burn to slow us down or will we be sucked in to the moon? maybe this step will need to be broken into 2 parts..

 

the final part been deceleration as falling towards the surface - it has been proposed that this is done in part by rocket propulsion and then airbags. The guidelines say the landing must be soft - not sure what they mean by this, we will have to wait till the official rules come out. I have suggested that (almost)current OTS jetpack technology be used for this phase.

 

Hope this sets some structure, feel free to expand on it :)

 

J

 

 

We can do better than the 5.7 km/sec from LEO to moon orbit figure you give.

 

We do it like this:

 

From LEO we place the craft into an orbit with an apogee of 322464 km. This places it within the Moon's Hill sphere.

 

Delta v required: 3.088km.sec

 

From here, we do a burn that reduces the relative velocity between the craft and the moon to 0.068km/sec. this will place it in an eccentric orbit around the moon with a perilune of 1835 km (100km above lunar surface)

 

Delta v: 0.727 km/sec

 

At perilune, we do a braking burn to circulize the orbit.

 

Delta v: 0.643 km/sec

 

Total delta v to moon orbit: 4.458 km/sec

 

 

With our best present chemical rockets (ISP 450), this gives us a mass ratio of 2.75. (compared to a mass ratio of 3.6 for the 5.7 km/sec figure.)

 

A Taurus XLS launch vehicle can deliver a payload of 1900 kg to LEO (price tag 32 million), meaning you could deliver 691 kg to Moon orbit

 

An Athena I can get 1805kg to LEO for a price tag of 17 million, allowing you to get 656 kg to the moon.

 

For the bargain price of 10 million, the Eurockot can get 1850 kg (673 kg to moon orbit) to LEO, but you have to launch from Russia.

[Turtle]

Library reference on heating/cooling in space: >> :)

 

New Science: Staying Cool on the Space Station

Part of the answer is heat exchangers. Designers created the "Active Thermal Control System" -- or ATCS for short -- to take away the extra heat. Waste heat is removed in two ways: through cold plates and heat exchangers, both of which are cooled by circulating water. Cold water runs through these heat-exchanging devices to cool the equipment running in the Station.

 

 

Not all of the outstretched arms of the Station are solar panels. Radiators to cool the Station are also large and obvious structures.

"First we remove excess heat by this very efficient liquid heat-exchange system," said Gene. "Then we send the energy to radiators that reject the heat into space."

 

But water circulated in pipes outside the space station would quickly freeze. So waste heat is exchanged a second time to another set of tubing containing ammonia instead of water. Ammonia freezes at -107 degrees F (-77 C) at standard atmospheric pressure. The heated ammonia then runs through large wing-like radiators located on the exterior of the Space Station, releasing the heat as infrared radiation.

[Turtle]

RC infrared-cam Hypog Lunar Rover prototype test #0001

 

YouTube - Hypog Lunar Rover Prototype - infrared camera http://www.youtube.com/watch?v=hSeKArTVJdw

[MITH]

Just a note on what Turtle said:

 

If you were to use the NASA method of heat exchange, what are you doing with the heat? Since we're on the issue of power supply, would not a logical reasoning be to use a passive energy production system ala turbine or something similar that could go "inline" with the heat transfer system. Just a quick thought.

 

BTW, has anybody started a thread to discuss the various methods for "soft landing". And we should make sure the links to the various threadshoots easy access.

 

Outs.

 

MITH

 

 

More Thoughts added:

 

Since we're on the issue of transmission of the signal, since we are intending to do multiple rovers, should we not put in place a semi-permanent relay station for some open standard so future missions can make use of it, as well as act as a central operations hub for the x mission.

[TheBigDog]

OK. The gears in the car are nylon and there is a high-low switch on the gear box, but short of building from scratch I see no way to "simply" re-gear the existing tranny. We might possibly control speed by using a rheostat on the motor circuit? More heat. :(

 

I put my 9 pound stone mortor on the car to simulate our 5 kilo mark and it drained the battery in short order with little headway forward and wouldn't drive in reverse or steer. (the car weighs about 2.5 pounds) I have one Ni-Cad and one Nickel-metal hydride 9.6 volt battery.

 

The red-headed neighbor kid suggested putting the camera on an articulaterd arm like the shuttle's Canada arm and also having the lander provide an enclosed garage for the rovers. Not sure about the arm (although it would accomplish the self-portrait requirement), but the garage idea might be the key to surviving the 2 week night for the $5 million bonus.

 

Having way too much fun,

Tortuga :eek_big:

Don't forget the gravity difference. 5kg on the moon takes less energy to overcome resistance of gravity for moving uphill and general rolling resistance on the bearings. What is the proper conversion factor?

 

If you can make a rover accomplish the mission with less weight, don't let me stop you. Think of 5kg as the maximum, not the requirement.

 

Bill

[freeztar]

Don't forget the gravity difference. 5kg on the moon takes less energy to overcome resistance of gravity for moving uphill and general rolling resistance on the bearings. What is the proper conversion factor?

 

The Moon's gravity is 1/6 that of Earth, so:

5kg*1/6=5/6kg=0.8333kg

 

So obviously the weight of the rovers once on the moon is fairly inconsequential compared to the weight of the rovers during takeoff.

 

We might consider increasing the maximum weight, *if needed*, as 4 rovers would currently weigh only 20kg on Earth which is not that much weight in the big scheme of things. Nonetheless, I think it is always a wise goal to strive for less. :eek_big:

[Turtle]

Don't forget the gravity difference. 5kg on the moon takes less energy to overcome resistance of gravity for moving uphill and general rolling resistance on the bearings. What is the proper conversion factor?

 

If you can make a rover accomplish the mission with less weight, don't let me stop you. Think of 5kg as the maximum, not the requirement.

 

Bill

 

So obviously the weight of the rovers once on the moon is fairly inconsequential compared to the weight of the rovers during takeoff.

 

Roger that fellas. I was even thinking on how to make centrifuge with a treadmill inside it to simulate Moon's gravity to test the driving.:eek::(

 

For one thing I think the equipment itself is going to be a major determining factor in the 'size' of the vehicles. I think 5 kg is unrealistically low. On another point, we will do well not to confuse weight & mass in all this. While Moon's gravity is less than Earth's, this only reduces the vehicles weight and we still have to accelerate the 5 kg of mass with our motor(s). The OTS RC vehicles aren't looking so good; underpowered and too much plastic.

 

Fly me to the Moon,:( :eek_big:

[freeztar]

Roger that fellas. I was even thinking on how to make centrifuge with a treadmill inside it to simulate Moon's gravity to test the driving.:eek::esmoking:

 

Wouldn't you need an anti-centrifuge? ;)

For one thing I think the equipment itself is going to be a major determining factor in the 'size' of the vehicles. I think 5 kg is unrealistically low.

 

You might be right, but we need a definitive parts list first to make that call, yeah?

On another point, we will do well not to confuse weight & mass in all this. While Moon's gravity is less than Earth's, this only reduces the vehicles weight and we still have to accelerate the 5 kg of mass with our motor(s).

Very good point! It would indeed require the same amount of joules to accelerate/decelerate the mass of the rovers wether here or on the moon. But weight should make a difference, particularly if we used a "hopper" design like CraigD suggested.

 

Here's a nice comparison graph I found.

 

The OTS RC vehicles aren't looking so good; underpowered and too much plastic.

 

Which cars have you been looking at? I remember from my days as a kid that the higher-end RC's were almost exclusively metal (once stripped of their body). Of course, they are much more expensive and I'm not sure about their power.

[TheBigDog]

Camera's and radios can be tested on any platform. We will move toward final rover designs with higher associated expense over time.

 

If 5 kg proves too low then we can change that. I think that the total engineering challenge will be similar in all sizes, but some of the costs can be constrained by keeping to a small size. A great deal can be done with 5 kg.

 

Bill

[Turtle]

Wouldn't you need an anti-centrifuge? ;)

 

I don't think so? From the drawing below, doesn't the "downward" force on the pan lesten as the centrifuge spins it to a 45 deg angle? :eek: :esmoking:

 

 

You might be right, but we need a definitive parts list first to make that call, yeah?

 

Affirmative

 

Very good point! It would indeed require the same amount of joules to accelerate/decelerate the mass of the rovers wether here or on the moon. But weight should make a difference, particularly if we used a "hopper" design like CraigD suggested.

 

Since we have in mind to have multiple rovers, I see no reason to not have them all different? People can work on whatever team or teams they fancy. yes/no?

 

Janus gave some masses for operational LEO launch systems and I wonder if there is any advantage is going below what a particular system is rated for? Keeping in mind we will have a considerable amount of mass involved beyond that of the individual rovers.

 

Here's a nice comparison graph I found.

 

Acknowledged.

 

Which cars have you been looking at? I remember from my days as a kid that the higher-end RC's were almost exclusively metal (once stripped of their body). Of course, they are much more expensive and I'm not sure about their power.

 

I borrowed a big electric car (Jeep Grand Cherokee body which I removed). It is 2-wheel drive with fat off-road tires & powered by a 9.6 volt battery. Manufacturer is Scientific Toys LLC & made in China (I have not put it in my mouth. ;)) It has a two-channel radio. The motor has a metal case, but it is entirely contained in a plastic gear-box and has a protrudung cooling fin array. I think the all-metal cars you have in mind are the gas-engine models?

[Turtle]

Camera's and radios can be tested on any platform. We will move toward final rover designs with higher associated expense over time.

 

If 5 kg proves too low then we can change that. I think that the total engineering challenge will be similar in all sizes, but some of the costs can be constrained by keeping to a small size. A great deal can be done with 5 kg.

 

Bill

 

Acknowledged. What I see as a problem for a small wheeled rover the size of an RC is that the terrain is then much rougher by scale. When making my prototype video, the car high-centered at the end on a small hummock of grass on a 2 inch "cliff" down to raked garden soil. I drove it all of 20 feet. :eek:;) The Moon's surface is no backyard. :esmoking:

[freeztar]

I don't think so? From the drawing below, doesn't the "downward" force on the pan lesten as the centrifuge spins it to a 45 deg angle? :eek: :esmoking:

 

I see what you are getting at, but you have to consider the x-axis vector as well, no?

Since we have in mind to have multiple rovers, I see no reason to not have them all different? People can work on whatever team or teams they fancy. yes/no?

 

I agree, to a point. I think the basic chassis and electronics should all be the same for manufacturing cost reasons, but it would definitely be great to have versatility in functions.

Janus gave some masses for operational LEO launch systems and I wonder if there is any advantage is going below what a particular system is rated for? Keeping in mind we will have a considerable amount of mass involved beyond that of the individual rovers.

 

My guess would be that the advantage would be more velocity, but we only really need "enough".

 

I borrowed a big electric car (Jeep Grand Cherokee body which I removed). It is 2-wheel drive with fat off-road tires & powered by a 9.6 volt battery. Manufacturer is Scientific Toys LLC & made in China (I have not put it in my mouth. ;))

 

;) I suppose we should start testing the effect of Hg on regolith.

 

The motor has a metal case, but it is entirely contained in a plastic gear-box and has a protrudung cooling fin array. I think the all-metal cars you have in mind are the gas-engine models?

 

Yes, now that I think of it, I am thinking of the gas-powered models. :doh:

[TheBigDog]

I was thinking that the wheels would be very oversized compared to an off the shelf RC, but I get your point about the scale of obstacles. I need to get my hands dirty with this.

 

Another thought I have had... what if the drives are hydrolic, and the motor is submerged in the fluid to absorb the heat? This could provide both the cooling for the motors and the ability to have other ways of moving the rover around.

 

Bill

[Turtle]

I see what you are getting at, but you have to consider the x-axis vector as well, no?

 

I haven't a real clue. :doh: Just looking for an excuse to build an expensive science thingy. :esmoking:

 

;) I suppose we should start testing the effect of Hg on regolith. ;)

 

I wonder if the contest rules will have environmental standards we have to meet? No oil spills allowed!?

 

I was thinking that the wheels would be very oversized compared to an off the shelf RC, but I get your point about the scale of obstacles. I need to get my hands dirty with this.

 

Then there is the matter of wheelbase length (front-to-back) and the "width" between wheels side-to-side(can't think of any automotive term for that measure just now). Another problem with smaller wheels is that for our given distance goal of 500 meters the smaller wheel/tire will experience more wear than a larger wheel/tire.

 

That's all I got. :eek: Ohh wait...it's not all. I found this camera looking for "miniature high resolution color video cameras". The only industrial source I found required registration. >> Sony EVI-HD1 HD High Definition PTZ Camera at a low price