Hypography X Prize Entry

[Roadam]

Originally Posted by CraigD

Units of mass and weight are confused in most nonscientific language. People commonly use kilograms as a unit of weight, when they should use Newtons. In the peculiar English/American system, pounds are both a unit of mass and force - units used only for mass in this system are very obscure – the slug (1 pound = 1 slug * 1 foot/second/second) and the blob (1 pound = 1 blob * 1 inch/second/second) – all the more reason, IMHO, not to use this weird old system if you can avoid it.

Rumor has it that one of the unsucesfull mars probes failed becouse of the problems with conversions from old english units to metric and vice versa.

Anyway, if we design something that will work on earth surface, it will surely work on the moon. Except for the convection driven heat transfer and lubricating. Something we need to test is strenght of any fuel tanks, double pressure instead of vacuum would be better. It could be good info if we would know if aerogels last in vacuum(for insulation). Batteries also have to be sturdy, as well as any camera.

[Kayra]

Originally Posted by CraigD

(Bolding mine)How do you plan to: 1) insert the vehicle into a low orbit? and 2) kill all orbital velocity? without a rocket motor and fuel?

Recall we’re dealing with the moon, so neither aerobraking (practically no atmosphere) nor electrodynamic propulsion (practically no magnetic field) are available alternatives, leaving the possibility of some sort of mechanical braking by bouncing/glancing/dragging something across the Moon’s rugged surface at several Km/s. I don’t think there’s any material capable of withstanding that!

Ahh, I should explain myself fully when I post (except I am often way too wordy as it is).
I was thinking of using the system Janus described (which I really liked BTW). Drop your orbital speed with a rocket and then discard the rocket, tanks, and structure you do not need.

At that point inflate the crash bag on the lower part of the lander (probably a modified cone shape) and extend a telescopic tower 5-15 meter above the lander. This will contain small rockets (pointing down on the cardinal points) to slow decent, and a camera to video the process, and again the physics of this are very simple to model. The position of the rockets would keep the crash pads pointing down, and the lander at a reasonably survivable speed.

The crash pad system using a modified honeycomb would require VERY little air to inflate because of the vacuum. Each cell in the crash pad is designed to burst at a specific spot with a hole diameter designed to allow the air out at a specific speed.

These systems and the physics involved are used constantly in the motion picture industry and the physics are well understood.

Rigging a test for this system should not be that challenging I would think, but not having the practical experience I will leave that to others to determine.

[TheBigDog]

I think I follow you, Kayra. How about if the rockets are only powerful enough to just overcome the gravity of the moon. We monitor the rate of descent. When the rate exceeds x we fire the rockets until the rate of descent falls below y. We then shut off the rocket until the rate of descent exceeds x again. All we are trying to do is stay in a range of speed which the airbag at the bottom of the lander will survive. I also think you are talking about a collapsing airbag, like the ones used for stunt jumps, rather than a bouncing method used for landing on mars. It is just there to absorb most of the energy of impact, but we don't exactly need to touch down gently. We can also film it that way. Very nice thought.

Bill

[TheFaithfulStone]

Originally Posted by BD

Control will be as follows: we will have a website that is actually hosted by the lander. From there we will be able to look at live camera shots from the rover, and issue commands to the rover. A command can be a series of maneuvers. We might tell it to turn 30 degrees, then move forward for 30 meters. It will begin the maneuver and continue until it is complete, or until it either gets a signal to stop. When it stops we will evaluate the position and send a signal for the next move. The lander will have a wheelbase of about half a meter. It will have a mast that extends up where the antenna for communication with the lander will be located. There will also be a probe used for recharging. I am considering having the lander able to auto guide the rover to the recharger, so once we get it close it can do the final distance with precision.

That's some pretty seriously complicated radio engineering.

I've built some dangerous remote control robots before, and I can tell you right now that the thing that breaks is the radio controller. Well, it doesn't even break so much as it totally doesn't work the way you expect it to. You'll need some pretty extensive pre-mission testing if you're going to have that much depend on a properly functioning relay station.

In a way, you're basically building a cell tower there, since you've got to store the signal and then send it out to a different receiver. (Twice, in fact, since you also get data from the rover over radio.) Also, I think you'll probably have to use two separate protocols for radio comm since you'll have about 2 seconds of lag from Earth to Base, and effectively instant comm between Base and Rover.

TFS

[Cold Fusion]

As a physicist I would like to participate. Count me in. Ad Astra

[TheBigDog]

Originally Posted by Cold Fusion

As a physicist I would like to participate. Count me in. Ad Astra

Welcome aboard! Do you have a particular area of interest in the mission?

Bill

[Kayra]

Greetings Cold Fusion.

Originally Posted by TheBigDog

I think I follow you, Kayra. How about if the rockets are only powerful enough to just overcome the gravity of the moon. We monitor the rate of descent. When the rate exceeds x we fire the rockets until the rate of descent falls below y. We then shut off the rocket until the rate of descent exceeds x again. All we are trying to do is stay in a range of speed which the airbag at the bottom of the lander will survive. I also think you are talking about a collapsing airbag, like the ones used for stunt jumps, rather than a bouncing method used for landing on mars. It is just there to absorb most of the energy of impact, but we don't exactly need to touch down gently. We can also film it that way. Very nice thought.

Bill

Simple, robust, and elegant BD. Exactly the control system that we need.

[Jay-qu]

So who has read the rules from post #151? I think its important that anyone participating has an intimate understanding of the rules. The more people that read it the more potential we have to finding shortcuts and the like

We dont want to waste time and effort running off on tangents that are either prohibited or useless given the current set of rules.

[freeztar]

Originally Posted by Jay-qu

So who has read the rules from post #151?

I have. I was quite surprised at the requirements (the camera reqs. in particular). We will have to factor these reqs. into our "master plan" as it influences mass, and everything else down the line.

I think its important that anyone participating has an intimate understanding of the rules. The more people that read it the more potential we have to finding shortcuts and the like

We dont want to waste time and effort running off on tangents that are either prohibited or useless given the current set of rules.

I agree.
That is why I proposed a mission outline back in post #50. The outline should include all mission requirements first and foremost.

[Turtle]

Originally Posted by Jay-qu

So who has read the rules from post #151? I think its important that anyone participating has an intimate understanding of the rules. The more people that read it the more potential we have to finding shortcuts and the like

We dont want to waste time and effort running off on tangents that are either prohibited or useless given the current set of rules.

I read them through & through today. Quite the remarkable amount of ruleage on the advertising, marketing, & legal-sign-away-your-rights-to-a-lot of-specific-stuff kind. No really. You have to include the X-prize peoples logo on the CRAFT in such a way so that it is included in the self portraits. Just one example.

On the cool side, if we produce a prototype early on that does it all on Earth, we can qualify for 'special' help. We can (well, have to) take it on tour for educational and promotional events. Right up BigDog's proposed alley! Also in that alley, the requirement that we encrypt our signal and give them the key of course.

Sorry for running on...what was the question? Oh yeah...yes I have read the rules.