In a message dated 09/08/2009 19:42:06 GMT Standard Time, nss@mwt.net writes:
Why is it that all re-entries always end in the ball of fire over just a few minutes. Why cannot the re-enetry energy be disipated over a longer period to make it more survivable. Of course, if they could, they would. It appears to be the nature of the beast. You are entering an ever denser medium, so the drag has to escallate and you end up with the 6/7 minute burn.
What if the surface of the re-entry vehicle radically changed during the
re-entry phase? As the density of the atomosphere increased, the surface area decreases. An ablative system that instead of burning off a thin skin of material as in most re-entry systems, you planned on burning off 95% of the original drag volume? What re-entry profile could be achieved Could we make a golfball core "pinger" that could survive?
Or, the not so 'cube'sat structure is an aerodynamic shape made from a cast ceramic material which glides in at a shallow angle allowing the energy to be dissipated over a much longer period of time. OK the solar cells burn off but an internal antenna would be OK as ceramics are fairly transparent to RF and a battery would provide the final hour or so of tlm. Would love to see the temp readings as it comes down. Would not love to be on the final end of the trajectory when it arrives.
David G0MRF
Exactly David,
This was my reasoning for trying to get the data I asked for in a earlier message.
I have been asking this for Years and No one EVER has been able to give me this info.
if i was a conspiracy guy i'd be in the boat with the moon landing guys that orbital space travel doesn't happen. Or at least manned never has happened,
But i'm not. but i am frustrated that the speed vs altitude at take off and re entry sseems to be totally un available.
because look at that
at take off we go from zero to 17580 Mph in what 10 minutes or so and are in orbit.
Yet the other way around gouing from 1780 to zero on 45 minutes causes the fireball effect with the friction.
Why not on the way up?
Thats what i want to be able ro read on the way up when it's at 60K feet it's moving at what speed, as wellas on the way down also,
and every other possible altitude,
I want to compare speeds at all altitudes.
we can go from zero to 17580 in ten min on the way up with no fireball, but take a slower, 450% slower return rate and it almost fries to a crisp.
Huh?
Joe WB9SBD
G0MRF@aol.com wrote:
Or, the not so 'cube'sat structure is an aerodynamic shape made from a cast ceramic material which glides in at a shallow angle allowing the energy to be dissipated over a much longer period of time. OK the solar cells burn off but an internal antenna would be OK as ceramics are fairly transparent to RF and a battery would provide the final hour or so of tlm. Would love to see the temp readings as it comes down. Would not love to be on the final end of the trajectory when it arrives.
David G0MRF
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Hi Joe Check out this URL: http://www.aerospaceweb.org/question/spacecraft/q0183.shtml
There is a table that shows the speed versus altitude for a shuttle launch. I think the key thing is that while it is in the thick part of the atmosphere ( I believe below 60k feet) the shuttle is going fairly slowly. It doesn't really get going until it is clear of the atmosphere.
I'm just guessing that on the return trip it is still going very fast when it gets to the thick atmosphere and hence, since there is nothing to slow it down except the atmosphere, it gets very hot. Does this make sense?
73, Pete WA6WOA
--- On Sun, 8/9/09, Joe nss@mwt.net wrote:
From: Joe nss@mwt.net Subject: [amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt To: G0MRF@aol.com Cc: amsat-bb@amsat.org Date: Sunday, August 9, 2009, 4:47 PM
Exactly David,
This was my reasoning for trying to get the data I asked for in a earlier message.
I have been asking this for Years and No one EVER has been able to give me this info.
if i was a conspiracy guy i'd be in the boat with the moon landing guys that orbital space travel doesn't happen. Or at least manned never has happened,
But i'm not. but i am frustrated that the speed vs altitude at take off and re entry sseems to be totally un available.
because look at that
at take off we go from zero to 17580 Mph in what 10 minutes or so and are in orbit.
Yet the other way around gouing from 1780 to zero on 45 minutes causes the fireball effect with the friction.
Why not on the way up?
Thats what i want to be able ro read on the way up when it's at 60K feet it's moving at what speed, as wellas on the way down also,
and every other possible altitude,
I want to compare speeds at all altitudes.
we can go from zero to 17580 in ten min on the way up with no fireball, but take a slower, 450% slower return rate and it almost fries to a crisp.
Huh?
Joe WB9SBD
G0MRF@aol.com wrote:
Or, the not so 'cube'sat structure is an aerodynamic shape made from a cast ceramic material which glides in at a shallow angle allowing the energy to be dissipated over a much longer period of time. OK the solar cells burn off but an internal antenna would be OK as ceramics are fairly transparent to RF and a battery would provide the final hour or so of tlm. Would love to see the temp readings as it comes down. Would not love to be on the final end of the trajectory when it arrives.
David G0MRF
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Ok we have half the numbers, This I also have gotten before a LOT, but coming back down, is no place. I want tosee these numbers.
Pete Rowe wrote:
Hi Joe Check out this URL: http://www.aerospaceweb.org/question/spacecraft/q0183.shtml
There is a table that shows the speed versus altitude for a shuttle launch. I think the key thing is that while it is in the thick part of the atmosphere ( I believe below 60k feet) the shuttle is going fairly slowly. It doesn't really get going until it is clear of the atmosphere.
I'm just guessing that on the return trip it is still going very fast when it gets to the thick atmosphere and hence, since there is nothing to slow it down except the atmosphere, it gets very hot. Does this make sense?
73, Pete WA6WOA
--- On Sun, 8/9/09, Joe nss@mwt.net wrote:
From: Joe nss@mwt.net Subject: [amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt To: G0MRF@aol.com Cc: amsat-bb@amsat.org Date: Sunday, August 9, 2009, 4:47 PM
Exactly David,
This was my reasoning for trying to get the data I asked for in a earlier message.
I have been asking this for Years and No one EVER has been able to give me this info.
if i was a conspiracy guy i'd be in the boat with the moon landing guys that orbital space travel doesn't happen. Or at least manned never has happened,
But i'm not. but i am frustrated that the speed vs altitude at take off and re entry sseems to be totally un available.
because look at that
at take off we go from zero to 17580 Mph in what 10 minutes or so and are in orbit.
Yet the other way around gouing from 1780 to zero on 45 minutes causes the fireball effect with the friction.
Why not on the way up?
Thats what i want to be able ro read on the way up when it's at 60K feet it's moving at what speed, as wellas on the way down also,
and every other possible altitude,
I want to compare speeds at all altitudes.
we can go from zero to 17580 in ten min on the way up with no fireball, but take a slower, 450% slower return rate and it almost fries to a crisp.
Huh?
Joe WB9SBD
G0MRF@aol.com wrote:
Or, the not so 'cube'sat structure is an aerodynamic shape made from a cast ceramic material which glides in at a shallow angle allowing the energy to be dissipated over a much longer period of time. OK the solar cells burn off but an internal antenna would be OK as ceramics are fairly transparent to RF and a battery would provide the final hour or so of tlm. Would love to see the temp readings as it comes down. Would not love to be on the final end of the trajectory when it arrives.
David G0MRF
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Yes this does make all the sence in the world, but why tho can no one find true actual data as this IS exactly what's hhappening?
I can find hundreds of pages a of data on the way up but not one single one for data onthe way down, That I would love to see.
Pete Rowe wrote:
Hi Joe Check out this URL: http://www.aerospaceweb.org/question/spacecraft/q0183.shtml
There is a table that shows the speed versus altitude for a shuttle launch. I think the key thing is that while it is in the thick part of the atmosphere ( I believe below 60k feet) the shuttle is going fairly slowly. It doesn't really get going until it is clear of the atmosphere.
I'm just guessing that on the return trip it is still going very fast when it gets to the thick atmosphere and hence, since there is nothing to slow it down except the atmosphere, it gets very hot. Does this make sense?
73, Pete WA6WOA
--- On Sun, 8/9/09, Joe nss@mwt.net wrote:
From: Joe nss@mwt.net Subject: [amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt To: G0MRF@aol.com Cc: amsat-bb@amsat.org Date: Sunday, August 9, 2009, 4:47 PM
Exactly David,
This was my reasoning for trying to get the data I asked for in a earlier message.
I have been asking this for Years and No one EVER has been able to give me this info.
if i was a conspiracy guy i'd be in the boat with the moon landing guys that orbital space travel doesn't happen. Or at least manned never has happened,
But i'm not. but i am frustrated that the speed vs altitude at take off and re entry sseems to be totally un available.
because look at that
at take off we go from zero to 17580 Mph in what 10 minutes or so and are in orbit.
Yet the other way around gouing from 1780 to zero on 45 minutes causes the fireball effect with the friction.
Why not on the way up?
Thats what i want to be able ro read on the way up when it's at 60K feet it's moving at what speed, as wellas on the way down also,
and every other possible altitude,
I want to compare speeds at all altitudes.
we can go from zero to 17580 in ten min on the way up with no fireball, but take a slower, 450% slower return rate and it almost fries to a crisp.
Huh?
Joe WB9SBD
G0MRF@aol.com wrote:
Or, the not so 'cube'sat structure is an aerodynamic shape made from a cast ceramic material which glides in at a shallow angle allowing the energy to be dissipated over a much longer period of time. OK the solar cells burn off but an internal antenna would be OK as ceramics are fairly transparent to RF and a battery would provide the final hour or so of tlm. Would love to see the temp readings as it comes down. Would not love to be on the final end of the trajectory when it arrives.
David G0MRF
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Joe,
I found a graph here
http://www.hq.nasa.gov/pao/History/conghand/possibil.htm
that shows speed versus altitude (in obscure units, but never mind) for both sounding rockets and orbital satellite launches (into a circular orbit)
It's not in the greatest detail.
Now to find the same data for the way down.
Sil ZL2CIA
at take off we go from zero to 17580 Mph in what 10 minutes or so and are in orbit. Yet the other way around going from 1780 to zero in 45 minutes causes the fireball effect with the friction.
Why not on the way up?
It does, its just that all the energy is being burned at the rear end of the rocket to produce the acceleration... see the flames... On the way down, you have to decelerate that same amount of acceleration in the opposite direction and remove all that LAUNCH energy, to come back down.... hence the flames.
The difference is that going up, you are going slowly in the higher density atmosphere which is continually lessening as you go up letting you go faster and faster with less and less friction. THus, no multiplying build up of friction.
Coming down, everything is against you. As you come down, into denser and denser atmosphere, the friction is increasing and increasing, the temperature building and building you are going slower and slower and falling faster and faster. Into one ultimate fireball.
we can go from zero to 17580 in ten min on the way up with no fireball, but take a slower, 450% slower return rate and it almost fries to a crisp.
Thats why I'm thinking there might be a way to change your drag coefficient as you come down to reduce the crescendo build up of heat and spread out the descent. But still, for something as small as a cubesat you still have to disipate about 300KWH of energy and even if you do this over an hour, thats still 300 killowatts of heat... (a number they used here in the presentation.. I'd like to see confirmation)...
Still seems like a fireball..
Bob, WB4APR
Bob Bruninga wrote:
at take off we go from zero to 17580 Mph in what 10 minutes or so and are in orbit. Yet the other way around going from 1780 to zero in 45 minutes causes the fireball effect with the friction.
Why not on the way up?
It does, its just that all the energy is being burned at the rear end of the rocket to produce the acceleration... see the flames... On the way down, you have to decelerate that same amount of acceleration in the opposite direction and remove all that LAUNCH energy, to come back down.... hence the flames.
No the flames are from friction with the atmosphere. if they had enough fuel they could do a 8 minute burn, and come straight down. The "Fuel" in this case is Gravity. The fuel on the way up is used to over come gravity.
The difference is that going up, you are going slowly in the higher density atmosphere which is continually lessening as you go up letting you go faster and faster with less and less friction. THus, no multiplying build up of friction.
But see where are the numbers to verify this? People make this statement all the time. but have yet to show any data that verifies this. Why is this soo hard to verify?
Coming down, everything is against you. As you come down, into denser and denser atmosphere, the friction is increasing and increasing, the temperature building and building you are going slower and slower and falling faster and faster. Into one ultimate fireball.
Yes and no, you are in free fall the whole time you are in orbit.
we can go from zero to 17580 in ten min on the way up with no fireball, but take a slower, 450% slower return rate and it almost fries to a crisp.
Thats why I'm thinking there might be a way to change your drag coefficient as you come down to reduce the crescendo build up of heat and spread out the descent. But still, for something as small as a cubesat you still have to disipate about 300KWH of energy and even if you do this over an hour, thats still 300 killowatts of heat... (a number they used here in the presentation.. I'd like to see confirmation)...
I'd like to see any data of speed vs altitude..
Joe
Still seems like a fireball..
Bob, WB4APR
Joe and the group... Here is 25 year old data of STS5
http://www.habitablezone.com/columbia/Archive/Dryden/Documents/H-1254_Therma lResponseShuttleWingReentryHeading.pdf
Go to page 7 of the PDF and see graph and you can take off altitude, velocity over time.
Google is a wonderful thing. Google "reentry velocity altitude shuttle"
But see where are the numbers to verify this? People make this statement all the time. but have yet to show any data that verifies this. Why is this soo hard to verify?
...Stuff deleted...
I'd like to see any data of speed vs altitude..
Joe
I'm crunching numbers right now, but just thought of something
ICBM's If we were to nuke RUSSIA or visa versa, while these yes do not get to orbit, they do get to just shy of orbital velocity, and re enter the atmosphere, did they have all these elaborate heat shields?
Alan VE4YZ wrote:
Joe and the group... Here is 25 year old data of STS5
http://www.habitablezone.com/columbia/Archive/Dryden/Documents/H-1254_Therma lResponseShuttleWingReentryHeading.pdf
Go to page 7 of the PDF and see graph and you can take off altitude, velocity over time.
Google is a wonderful thing. Google "reentry velocity altitude shuttle"
But see where are the numbers to verify this? People make this statement all the time. but have yet to show any data that verifies this. Why is this soo hard to verify?
...Stuff deleted...
I'd like to see any data of speed vs altitude..
Joe
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At 01:41 PM 8/10/2009, you wrote:
I'm crunching numbers right now, but just thought of something
ICBM's If we were to nuke RUSSIA or visa versa, while these yes do not get to orbit, they do get to just shy of orbital velocity, and re enter the atmosphere, did they have all these elaborate heat shields?
I believe a lot of work on atmospheric entry (i.e. heat shielding) systems did actually start from the early days of ICBMs for this very reason. I don't think the speeds are that close to orbital speeds (one only needs to fall 3000 miles away, not 8000+), though they are high enough that the warheads must be designed to survive re-entry.
There's a bit about ICBM re-entry systems on Wikipedia
http://en.wikipedia.org/wiki/Atmospheric_reentry
73 de VK3JED / VK3IRL http://vkradio.com
During its flight testing of the Delta Clipper vehicle I asked Bill Gaubatz (spell last name) the program manager if the shape of the vehicle had been tested toward re entry and his line was "A lot of times, go look at the pictures from the Kwajalien atoll."
Robert WB5MZO
Date: Mon, 10 Aug 2009 14:24:01 +1000 To: amsat-bb@amsat.org From: vk3jed@gmail.com Subject: [amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt
At 01:41 PM 8/10/2009, you wrote:
I'm crunching numbers right now, but just thought of something
ICBM's If we were to nuke RUSSIA or visa versa, while these yes do not get to orbit, they do get to just shy of orbital velocity, and re enter the atmosphere, did they have all these elaborate heat shields?
I believe a lot of work on atmospheric entry (i.e. heat shielding) systems did actually start from the early days of ICBMs for this very reason. I don't think the speeds are that close to orbital speeds (one only needs to fall 3000 miles away, not 8000+), though they are high enough that the warheads must be designed to survive re-entry.
There's a bit about ICBM re-entry systems on Wikipedia
http://en.wikipedia.org/wiki/Atmospheric_reentry
73 de VK3JED / VK3IRL http://vkradio.com
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_________________________________________________________________ Get back to school stuff for them and cashback for you. http://www.bing.com/cashback?form=MSHYCB&publ=WLHMTAG&crea=TEXT_MSHY...
Why shouls someone spend money making measurements to get your figures? The current system already works. There's nothing broken that needs to be fixed.
Joe wrote:
But see where are the numbers to verify this? People make this statement all the time. but have yet to show any data that verifies this. Why is this soo hard to verify?
Bob Bruninga wrote:
The difference is that going up, you are going slowly in the higher density atmosphere which is continually lessening as you go up letting you go faster and faster with less and less friction. THus, no multiplying build up of friction.
Bob,
I hesitate to say this, but I'm almost certain that re-entry heating is not caused by friction (well may be 10%). Most reliable sources, NASA included, attribute re-entry heating to shock wave compression of the air in front of the descending craft.
Sil ZL2CIA
Sil - ZL2CIA wrote:
Bob Bruninga wrote:
The difference is that going up, you are going slowly in the higher density atmosphere which is continually lessening as you go up letting you go faster and faster with less and less friction. THus, no multiplying build up of friction.
Bob,
I hesitate to say this, but I'm almost certain that re-entry heating is not caused by friction (well may be 10%). Most reliable sources, NASA included, attribute re-entry heating to shock wave compression of the air in front of the descending craft.
Sil ZL2CIA
Wikipeadia reckon 80% of the heating experienced by a re-entering orbiter (shuttle) is the result of compression, leaving 20% to friction.
The 90% figure might be more correctly applied to the Apollo re-entry vehicle. It was a very different shape.
Some highspeed vehicles did experience severe heating, notably the amazing X-15 craft.
The question is a good one, but the answer has needs to consider far more than frictional heating, since that accounts for only a small part of the energy that is converted to heat during re-entry.
I have no idea what the equivalent ratio is on the way up, but it is a delightful puzzle. Thanks Joe.
Sil ZL2CIA
Sil
According to the "Apollo 11 Owner's Workshop Manual" recently published by Haynes here in the UK page 71
"Atmospheric Heating" Frictional heating was not just a problem during re-entry. During the acceleration after launch through the thicker, lower atmosphere, the apex of the command module would also be exposed to aerodynamic heating and needed protection by an additional cork and fibreglass shroud attached to the launch escape tower. The far more intense re-entry heating is often mistakenly thought to be something to do with friction with the passing air. In fact the extra heating during re-entry is more comparable to the heat that builds up in a valve in a bicycle pump as air is compressed into a tyre. When any gas is compressed the amount of energy that it holds in a given volume rises. When the air in front of a blunt hypersonic craft cannot move aside fast enough it becomes compressed and so heats up for the same reason. During re-entry the speeds, and therefore the compression, are so great that the temperature can easily rise into the thousands of degrees, approaching the same sort of temperature as on the surface of the sun (5,500C) . The advantage of the blunt shape has in this process over a more streamlined form is that by creating this compressed layer of air ahead of it, the main part of the craft is separated from the hottest and most damaging heat."
So all we need is a cubesat containing a deorbit propulsion system so that the landing point can be carefully selected, which has inside it, a miniature Apollo shaped capsule made of titanium with a heat shield on the blunt end and which has ceramic panels so that the inbuilt GPS can receive and the VHF or UHF or S band transmitter can transmit.:)
73
Graham G3VZV
PS The Haynes Manual is available from the RSGB
----- Original Message ----- From: "Sil - ZL2CIA" zl2cia@amsat.org To: "Bob Bruninga" bruninga@usna.edu; "Amsat Reflector" amsat-bb@amsat.org Sent: Monday, August 10, 2009 9:40 AM Subject: [amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt
Bob Bruninga wrote:
The difference is that going up, you are going slowly in the higher density atmosphere which is continually lessening as you go up letting you go faster and faster with less and less friction. THus, no multiplying build up of friction.
Bob,
I hesitate to say this, but I'm almost certain that re-entry heating is not caused by friction (well may be 10%). Most reliable sources, NASA included, attribute re-entry heating to shock wave compression of the air in front of the descending craft.
Sil ZL2CIA _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Graham,
Cool. But still no cigar as far as Joe's question.
So.. the broad flat shape generates more compressive heating, than the more pointy nose of the launch vehicle. But... the launch vehicle is still going to generate a great deal of heat through the same process if it is doing the same hypersonic speed at the same altitude.
So is it?
Sil
Graham Shirville wrote:
According to the "Apollo 11 Owner's Workshop Manual" recently published by Haynes here in the UK page 71
"Atmospheric Heating" Frictional heating was not just a problem during re-entry. During the acceleration after launch through the thicker, lower atmosphere, the apex of the command module would also be exposed to aerodynamic heating and needed protection by an additional cork and fibreglass shroud attached to the launch escape tower. The far more intense re-entry heating is often mistakenly thought to be something to do with friction with the passing air. In fact the extra heating during re-entry is more comparable to the heat that builds up in a valve in a bicycle pump as air is compressed into a tyre. When any gas is compressed the amount of energy that it holds in a given volume rises. When the air in front of a blunt hypersonic craft cannot move aside fast enough it becomes compressed and so heats up for the same reason. During re-entry the speeds, and therefore the compression, are so great that the temperature can easily rise into the thousands of degrees, approaching the same sort of temperature as on the surface of the sun (5,500C) . The advantage of the blunt shape has in this process over a more streamlined form is that by creating this compressed layer of air ahead of it, the main part of the craft is separated from the hottest and most damaging heat."
So all we need is a cubesat containing a deorbit propulsion system so that the landing point can be carefully selected, which has inside it, a miniature Apollo shaped capsule made of titanium with a heat shield on the blunt end and which has ceramic panels so that the inbuilt GPS can receive and the VHF or UHF or S band transmitter can transmit.:)
73
Graham G3VZV
PS The Haynes Manual is available from the RSGB
Yeah, it might wind up being a super-sonic "Lawn Dart"! Jim KQ6EA
--- On Sun, 8/9/09, G0MRF@aol.com G0MRF@aol.com wrote:
From: G0MRF@aol.com G0MRF@aol.com Subject: [amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt To: bruninga@usna.edu Cc: amsat-bb@amsat.org Date: Sunday, August 9, 2009, 4:31 PM
In a message dated 09/08/2009 19:42:06 GMT Standard Time, nss@mwt.net writes:
Why is it that all re-entries always end in the ball of fire over just a few minutes. Why cannot the re-enetry energy be disipated over a longer period to make it more survivable. Of course, if they could, they would. It appears to be the nature of the beast. You are entering an ever denser medium, so the drag has to escallate and you end up with the 6/7 minute burn.
What if the surface of the re-entry vehicle radically changed during the
re-entry phase? As the density of the atomosphere increased, the surface area decreases. An ablative system that instead of burning off a thin skin of material as in most re-entry systems, you planned on burning off 95% of the original drag volume? What re-entry profile could be achieved Could we make a golfball core "pinger" that could survive?
Or, the not so 'cube'sat structure is an aerodynamic shape made from a cast ceramic material which glides in at a shallow angle allowing the energy to be dissipated over a much longer period of time. OK the solar cells burn off but an internal antenna would be OK as ceramics are fairly transparent to RF and a battery would provide the final hour or so of tlm. Would love to see the temp readings as it comes down. Would not love to be on the final end of the trajectory when it arrives.
David G0MRF
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Having considered this yesterday I decided to 'keep quiet' but having woken this morning to David's ceramic suggestion I'll add my own pennyworth.
As the Shuttle uses ceramic tiles it seemed logical to suggest that a device embedded within such a material would serve the purpose. Perhaps move away from the cube design to a classic "flying saucer" shape.
As David says, the ceramic is transparent to RF, a classic saucer shape offers two significant surfaces for solar cells; sized correctly the circumference could provide for an embedded (and therefore protected) dipole and if re-entry could be engineered to occur 'edge on' a minimal profile would be presented.
I wonder if they have "B" grade (Shuttle) tiles left over?
David G8OQW
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-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of G0MRF@aol.com Sent: 10 August 2009 00:31 To: bruninga@usna.edu Cc: amsat-bb@amsat.org Subject: [amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt
Or, the not so 'cube'sat structure is an aerodynamic shape made from a cast ceramic material which glides in at a shallow angle allowing the energy to be dissipated over a much longer period of time. OK the solar cells burn off but an internal antenna would be OK as ceramics are fairly transparent to RF and a battery would provide the final hour or so of tlm. Would love to see the temp readings as it comes down. Would not love to be on the final end of the trajectory when it arrives.
David G0MRF
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participants (12)
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Alan VE4YZ -
Bob Bruninga -
David Barber -
G0MRF＠aol.com -
Graham Shirville -
Jim Jerzycke -
Joe -
Nigel Gunn G8IFF/W8IFF -
Pete Rowe -
Rocky Jones -
Sil - ZL2CIA -
Tony Langdon