Re: Radio control v. Wire... and 1 part or 2?
On Mon, 28 Oct 2002 [EMAIL PROTECTED] wrote: Are we going to have this thing radio controlled or a cable/wire attached to it? From the CalTech glaciology website... For electromagnetic waves with frequencies from 5 to 300 MHz the loss of energy by absorption in ice is sufficiently small that they can penetrate large ice masses great distances. This means that a radio controlled or transmitting device won't be a problem, but are we going to have a camera on this device? That would require that we did have a cable running to the surface because TV signals are much greater than that correct? Normal VHF TV signals are located below and above the frequency range used by FM radio (~92-105 MHz). I believe each channel requires from 6-10 MHz of bandwidth. If one uses MPEG-4 compression (requires probably a Pentium-III class processor or greater in the Cryobot consuming 20-40W of power) then one can probably get the bandwidth requirements down to 1-2 MHz or less. So if the ice absorption figures are accurate, then I don't see the need for any relay stations at all. Self navigation would require some good A.I. and computer power and we are planning on leaving it down there correct? I think several robotics labs (MIT, CMU and Los Alamos come to mind) have developed quite robust self-navigation software for robots. Of course this would need to be adapted to navigating in ice. Radio waves are reflected by inhomogeneities in the ice and at material boundaries, especially at the ice-water and ice-rock interfaces If our little cryobot does maneuver around boulders/asteroids in the ice, the radio control could get lost because of their interference. This only seems to be important if one needs a high bandwidth signal. Video out could apply enough ECC. Control signals in are very low bandwidth so this would not seem to be a problem. It is worth noting that since ice is a solid material, one might consider ultrasonic signals (at least for the inputs). These might be able to go up to several MHz without becoming too corrupted by the inhomogeneities. Given the likely rate of progress of the probe I can't imagine more than a few kHz of input information being required. Robert == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
RE: Radio control v. Wire... and 1 part or 2?
A few miles of light-transmitting fiber spooled out behind the cryobot shouldn't weigh any more than the proposed transmission "pucks". Also, if a metallic filament were adjacent the optical line(s), it could be periodically heated to reposition and de-stress itself in the event of ice movement. Jack -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Monday 28 October 2002 05:45 To: [EMAIL PROTECTED] Subject: Radio control v. Wire... and 1 part or 2? Are we going to have this thing radio controlled or a cable/wire attached to it? >From the CalTech glaciology website... For electromagnetic waves with frequencies from 5 to 300 MHz the loss of energy by absorption in ice is sufficiently small that they can penetrate large ice masses great distances. This means that a radio controlled or transmitting device won't be a problem, but are we going to have a camera on this device? That would require that we did have a cable running to the surface because TV signals are much greater than that correct? We would want to see where this thing is going and what it sees. And it would be helpful with the navigation around any obstacles. I know that the end model should be self-sufficient, with the ability to navigate on it's own around obstacles but for this first experiment we might be biting off more than we can chew. Self navigation would require some good A.I. and computer power and we are planning on leaving it down there correct? Some ideas and price ranges FM and AM Transmitters, professional radio equipment, FM power amplifiers Second reason why a cable attached would be more beneficial to our model is... Radio waves are reflected by inhomogeneities in the ice and at material boundaries, especially at the ice-water and ice-rock interfaces If our little cryobot does maneuver around boulders/asteroids in the ice, the radio control could get lost because of their interference. Also what package are we trying to deliver when we get through the ice? Is this cryobot an ice melter and an ocean explorer? Or should we have an ice melter casing that then is carrying an ocean explore/biological detection package? It would seem that the NASA funded and the better of the two would be the 2 part. It would be much better/faster/cheaper for us to concentrate on just a casing that can melt through the ice to deliver a then water exploring ROV. Should we split into two groups to design the two parts now to save time instead of one and then the other?
RE: Radio control v. Wire... and 1 part or 2?
On Mon, 28 Oct 2002, Reeve, Jack W. wrote: A few miles of light-transmitting fiber spooled out behind the cryobot shouldn't weigh any more than the proposed transmission pucks. Also, if a metallic filament were adjacent the optical line(s), it could be periodically heated to reposition and de-stress itself in the event of ice movement. That appears to be what NASA did with its Antarctic missions, but they didn't attempt to heat the wire. They used heated water drilling to drill a big hole then lowered the probe down the hole attached to fiber optics as best I can tell. Review the slides from the URL I posted earlier. Robert == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
RE: Radio control v. Wire... and 1 part or 2?
A little additional thought would be to enshroud the data fibers with a metallic outer wrap, then energize that for heat for repositioning and distressing in the event of ice movement. Another potential advantage of a light cable spooled out from the probe is it would give the probe purchase upon which to climb in the event of the need to choose another path due to massive planar inclusions or other significant obstacles. The notion of harnessing the radiation fields present to generate electrical energy is very intriguing. If that were possible, the tether AND the probe could be energized from a surface mechanism, thereby allowing the tether to be spooled out from the surface, freeing the probe of this burden. Jack -Original Message- From: Robert J. Bradbury [mailto:bradbury;aeiveos.com] Sent: Monday 28 October 2002 13:49 To: [EMAIL PROTECTED] Subject: RE: Radio control v. Wire... and 1 part or 2? On Mon, 28 Oct 2002, Reeve, Jack W. wrote: A few miles of light-transmitting fiber spooled out behind the cryobot shouldn't weigh any more than the proposed transmission pucks. Also, if a metallic filament were adjacent the optical line(s), it could be periodically heated to reposition and de-stress itself in the event of ice movement. That appears to be what NASA did with its Antarctic missions, but they didn't attempt to heat the wire. They used heated water drilling to drill a big hole then lowered the probe down the hole attached to fiber optics as best I can tell. Review the slides from the URL I posted earlier. Robert == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
RE: Radio control v. Wire... and 1 part or 2?
How big is this thing supposed to be? Depending on the mass, crawling back up a fire optic cable is almost guaranteed to break it. Fiber is small and it does not have a lot of tensile strength. Joe On Mon, 2002-10-28 at 13:42, Reeve, Jack W. wrote: A little additional thought would be to enshroud the data fibers with a metallic outer wrap, then energize that for heat for repositioning and distressing in the event of ice movement. Another potential advantage of a light cable spooled out from the probe is it would give the probe purchase upon which to climb in the event of the need to choose another path due to massive planar inclusions or other significant obstacles. The notion of harnessing the radiation fields present to generate electrical energy is very intriguing. If that were possible, the tether AND the probe could be energized from a surface mechanism, thereby allowing the tether to be spooled out from the surface, freeing the probe of this burden. Jack -Original Message- From: Robert J. Bradbury [mailto:bradbury;aeiveos.com] Sent: Monday 28 October 2002 13:49 To: [EMAIL PROTECTED] Subject: RE: Radio control v. Wire... and 1 part or 2? On Mon, 28 Oct 2002, Reeve, Jack W. wrote: A few miles of light-transmitting fiber spooled out behind the cryobot shouldn't weigh any more than the proposed transmission pucks. Also, if a metallic filament were adjacent the optical line(s), it could be periodically heated to reposition and de-stress itself in the event of ice movement. That appears to be what NASA did with its Antarctic missions, but they didn't attempt to heat the wire. They used heated water drilling to drill a big hole then lowered the probe down the hole attached to fiber optics as best I can tell. Review the slides from the URL I posted earlier. Robert == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
RE: Radio control v. Wire... and 1 part or 2?
I am assuming we are discussing a trial model here on Earth. It'll be in a water environment, so its buoyancy could be made whatever you want, but I'd say 30-40% of its weight in air. Also, the tether would have considerable tensile strength via its metal sheath, not from the optical fibers. My guess is that at surface, fully loaded with say a mile of cable, it'd be in the neighborhood of 100 kilos or less. I wouldn't worry about the climbing/respooling feature at this time. When we do though, I was thinking of a spooling desing like a covered spin casting reel for fishing, where the line plays out through a hole at end/center. Jack -Original Message- From: Joe Latrell [mailto:joe_latrell;beyond-earth.com] Sent: Monday 28 October 2002 15:24 To: [EMAIL PROTECTED] Subject: RE: Radio control v. Wire... and 1 part or 2? How big is this thing supposed to be? Depending on the mass, crawling back up a fire optic cable is almost guaranteed to break it. Fiber is small and it does not have a lot of tensile strength. Joe On Mon, 2002-10-28 at 13:42, Reeve, Jack W. wrote: A little additional thought would be to enshroud the data fibers with a metallic outer wrap, then energize that for heat for repositioning and distressing in the event of ice movement. Another potential advantage of a light cable spooled out from the probe is it would give the probe purchase upon which to climb in the event of the need to choose another path due to massive planar inclusions or other significant obstacles. The notion of harnessing the radiation fields present to generate electrical energy is very intriguing. If that were possible, the tether AND the probe could be energized from a surface mechanism, thereby allowing the tether to be spooled out from the surface, freeing the probe of this burden. Jack -Original Message- From: Robert J. Bradbury [mailto:bradbury;aeiveos.com] Sent: Monday 28 October 2002 13:49 To: [EMAIL PROTECTED] Subject: RE: Radio control v. Wire... and 1 part or 2? On Mon, 28 Oct 2002, Reeve, Jack W. wrote: A few miles of light-transmitting fiber spooled out behind the cryobot shouldn't weigh any more than the proposed transmission pucks. Also, if a metallic filament were adjacent the optical line(s), it could be periodically heated to reposition and de-stress itself in the event of ice movement. That appears to be what NASA did with its Antarctic missions, but they didn't attempt to heat the wire. They used heated water drilling to drill a big hole then lowered the probe down the hole attached to fiber optics as best I can tell. Review the slides from the URL I posted earlier. Robert == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
