Bob:
Shown in this message is a picture of the revised module design that you and I have been working on in the last few days. The revised cover has not yet been done but its features are implicated in this current view. The machined base plate has robust beams around three sides. Further, there are stiffening beams machined on the bottom side of the baseplate. The side to side dimension of the baseplate is shown at 141mm, reduced from its previous 147mm. This step was needed to accommodate the cover screw heads now on the side of the module.
Shown also is a revised connector plate, which is increased in width from the previous 122mm to the 141mm of the baseplate. This should ease the connector space issue a little as the cover PEM nuts have accordingly been moved out leaving a 125mm wide clear space for connector activity, an increase from 106mm.
The PCB is unchanged, however its standoff posts are now 6.4mm (1/4 inch) from the previous 4.8mm (3/16 inch), a step needed for connector plate screws.
The cover will slide over the assembly shown and it will have only one flange, along the rear side. The long sides will use screws placed into the edges of the assembly (formerly a flanged side). This means that there will not be mechanical loading on the baseplate caused by irregular flange bends, as in the present cover design.
Regarding this design of module, the PCB access has been fully maintained, but the cover cannot be removed while the module is installed into the spacecraft, a feature that had been planned with the current design.
Discussion is invited.
Dick Jansson, KD1K mailto:kd1k@amsat.org kd1k@amsat.org mailto:kd1k@arrl.net kd1k@arrl.net
125x180 Module Assembly.jpg
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
On 10/15/07, Dick Jansson-rr rjansson@cfl.rr.com wrote:
Bob:
Shown in this message is a picture of the revised module design that you and I have been working on in the last few days. The revised cover has not yet been done but its features are implicated in this current view. The machined base plate has robust beams around three sides. Further, there are stiffening beams machined on the bottom side of the baseplate. The side to side dimension of the baseplate is shown at 141mm, reduced from its previous 147mm. This step was needed to accommodate the cover screw heads now on the side of the module.
Shown also is a revised connector plate, which is increased in width from the previous 122mm to the 141mm of the baseplate. This should ease the connector space issue a little as the cover PEM nuts have accordingly been moved out leaving a 125mm wide clear space for connector activity, an increase from 106mm.
The PCB is unchanged, however its standoff posts are now 6.4mm (1/4 inch) from the previous 4.8mm (3/16 inch), a step needed for connector plate screws.
The cover will slide over the assembly shown and it will have only one flange, along the rear side. The long sides will use screws placed into the edges of the assembly (formerly a flanged side). This means that there will not be mechanical loading on the baseplate caused by irregular flange bends, as in the present cover design.
Regarding this design of module, the PCB access has been fully maintained, but the cover cannot be removed while the module is installed into the spacecraft, a feature that had been planned with the current design.
Discussion is invited.
Dick Jansson, KD1K
kd1k@amsat.org
kd1k@arrl.net
[image: 125x180 Module Assembly.jpg]
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Juan:
Thank you for your comments.
The truly "high power" modules, such as transmitters with power dissipating devices of many Watts will still need to be constructed using the E05 01 (1100 alloy aluminum) Heat Sink, which will in turn be bolted directly to the spaceframe panel (Y side).
The intermediate power modules, such as the URx with the small internal heat sinks could be special variation of the shown milled baseplate. With such a provision, however, you would not have the latitude to shift the location of the heat sink as you have done already without changing the mechanical dimensions of the machined part, thus calling for another special part. It also raises issues of the precision of locating such heat sink pads. I like the concept, however, if it can be worked out, but it will require some pretty good dimensional control.
Your concept of having the entire PCB rest on a thermal plate raises many issues. Among them is the fact that you very often have traces on the bottom side, placing them on the aluminum would not be very "cool" electrically speaking. This issue also raises other issues, such as flatness. There are Juan's flatness and then there is Dick's thermal flatness and these two worlds are probably very much different. Any kind of protrusion, traces or solder lumps or vias will take such a surface quickly out of the class of being a thermal surface into a Juan surface. Any non-purely-flat-surface becomes non-acceptable as a thermal surface. That is why the heat sinks for the URx are only in contact with specific copper-faced areas on the bottom of the URx PCB.
Your thermal gap filler material offers also only limited help, even if it is space-worthy. Space worthiness is a matter of the outgassing characteristics of the material, and most of these kind of materials are not space acceptable. The thermal characteristics of such materials may also be pretty limited, when I compare them to some of the power-density heat flow needs.
Compared to locally clamping a PCB to a bottom heat sink, your bridge idea does not conduct much heat. We can very quickly get into a discussion of the conductance values of such heat sinking methods and in those discussions the bridge method runs out of steam rapidly. You certainly would not need top as well as the bottom heat sinking of a locale on a PCB.
Thanks for the discussions. '73, Dick Jansson, KD1K mailto:kd1k@amsat.org kd1k@amsat.org mailto:kd1k@arrl.net kd1k@arrl.net
From: wa6htp@gmail.com [mailto:wa6htp@gmail.com] On Behalf Of Juan Rivera Sent: Monday, 15 October, 2007 15.38 To: Dick Jansson-rr Cc: Bob Davis; AMSAT Eagle Subject: Re: [eagle] Revised Module Suggestion
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
We have good control over hole locations on the PCB. If the board edges are placed 10 mils from the inside surfaces of the module, all holes will be within 5 mils of the specified location.
Having the entire PCB rest on a plate might be useful for S2 and C band. The PCB dielectric should be 30 mils or less in thickness to minimize EM radiation losses and the dielectric material is much less rigid than the fiberglass used at lower frequencies. Microstrip circuits have a solid ground plane on the bottom.
73,
John KD6OZH ----- Original Message ----- From: Dick Jansson-rr To: 'Juan Rivera' Cc: 'AMSAT Eagle' Sent: Monday, October 15, 2007 17:40 UTC Subject: [eagle] Re: Revised Module Suggestion
Juan:
Thank you for your comments.
The truly "high power" modules, such as transmitters with power dissipating devices of many Watts will still need to be constructed using the E05 01 (1100 alloy aluminum) Heat Sink, which will in turn be bolted directly to the spaceframe panel (Y side).
The intermediate power modules, such as the URx with the small internal heat sinks could be special variation of the shown milled baseplate. With such a provision, however, you would not have the latitude to shift the location of the heat sink as you have done already without changing the mechanical dimensions of the machined part, thus calling for another special part. It also raises issues of the precision of locating such heat sink pads. I like the concept, however, if it can be worked out, but it will require some pretty good dimensional control.
Your concept of having the entire PCB rest on a thermal plate raises many issues. Among them is the fact that you very often have traces on the bottom side, placing them on the aluminum would not be very "cool" electrically speaking. This issue also raises other issues, such as flatness. There are Juan's flatness and then there is Dick's thermal flatness and these two worlds are probably very much different. Any kind of protrusion, traces or solder lumps or vias will take such a surface quickly out of the class of being a thermal surface into a Juan surface. Any non-purely-flat-surface becomes non-acceptable as a thermal surface. That is why the heat sinks for the URx are only in contact with specific copper-faced areas on the bottom of the URx PCB.
Your thermal gap filler material offers also only limited help, even if it is space-worthy. Space worthiness is a matter of the outgassing characteristics of the material, and most of these kind of materials are not space acceptable. The thermal characteristics of such materials may also be pretty limited, when I compare them to some of the power-density heat flow needs.
Compared to locally clamping a PCB to a bottom heat sink, your bridge idea does not conduct much heat. We can very quickly get into a discussion of the conductance values of such heat sinking methods and in those discussions the bridge method runs out of steam rapidly. You certainly would not need top as well as the bottom heat sinking of a locale on a PCB.
Thanks for the discussions.
'73,
Dick Jansson, KD1K
kd1k@amsat.org
kd1k@arrl.net
From: wa6htp@gmail.com [mailto:wa6htp@gmail.com] On Behalf Of Juan Rivera Sent: Monday, 15 October, 2007 15.38 To: Dick Jansson-rr Cc: Bob Davis; AMSAT Eagle Subject: Re: [eagle] Revised Module Suggestion
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
------------------------------------------------------------------------------
_______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Juan:
There is another issue that comes to mind regarding "specialized" modules. In a program such as Eagle we will need to create an acceptable module design that is useful for many applications in the mission and then turn on the fabrication machinery for producing these long before the electronic forces are ready to populate them for flight. On P3D in 1992-3 we gambled and manufactured a very many module parts, expecting that we would have some spares left over - wrong! Even with this quite large quantity of parts (and at that time there was criticism that we were making too many) we ran out before flight and had to make some more.
Fabricating module parts for this program is a guessing game, with some estimates of needing to construct up to 80 sets of parts, and that may not be enough. You can do the detailed program mathematics and come up with some number and I will be willing to bet that you end up on the wrong side of that guess. It's a dicey game.
The lesson in this is that we must create a generic module design and hardware that can be adapted for many different assignments in the spacecraft. Save for your specialized need, we have no indication of any other specialized module needs. This is why I prefer to adapt a generic module to your needs with the added heat sinks, rather than make just a specially machined device just for your needs. And if we do, we will probably not have enough of them. This is why I prefer to have a generic module design and then carefully adapt it as required for specialized module needs. We will be flying more than just the U receiver!.
'73, Dick Jansson, KD1K mailto:kd1k@amsat.org kd1k@amsat.org mailto:kd1k@arrl.net kd1k@arrl.net
From: wa6htp@gmail.com [mailto:wa6htp@gmail.com] On Behalf Of Juan Rivera Sent: Monday, 15 October, 2007 15.38 To: Dick Jansson-rr Cc: Bob Davis; AMSAT Eagle Subject: Re: [eagle] Revised Module Suggestion
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
Hi Dick,
When considering special needs, don't forget that the IHU has already been designed and will need a box to accommodate it. You did this once, but with the new box designs, it may need to be done again.
Chuck
Dick Jansson-rr wrote:
Juan:
There is another issue that comes to mind regarding “specialized” modules. In a program such as Eagle we will need to create an acceptable module design that is useful for many applications in the mission and then turn on the fabrication machinery for producing these long before the electronic forces are ready to populate them for flight. On P3D in 1992-3 we gambled and manufactured a very many module parts, expecting that we would have some spares left over – wrong! Even with this quite large quantity of parts (and at that time there was criticism that we were making too many) we ran out before flight and had to make some more.
Fabricating module parts for this program is a guessing game, with some estimates of needing to construct up to 80 sets of parts, and that may not be enough. You can do the detailed program mathematics and come up with some number and I will be willing to bet that you end up on the wrong side of that guess. It’s a dicey game.
The lesson in this is that we must create a generic module design and hardware that can be adapted for many different assignments in the spacecraft. Save for your specialized need, we have no indication of any other specialized module needs. This is why I prefer to adapt a generic module to your needs with the added heat sinks, rather than make just a specially machined device just for your needs. And if we do, we will probably not have enough of them. This is why I prefer to have a generic module design and then carefully adapt it as required for specialized module needs. We will be flying more than just the U receiver!.
’73,
Dick Jansson, KD1K
kd1k@amsat.org mailto:kd1k@amsat.org
kd1k@arrl.net mailto:kd1k@arrl.net
*From:* wa6htp@gmail.com [mailto:wa6htp@gmail.com] *On Behalf Of *Juan Rivera *Sent:* Monday, 15 October, 2007 15.38 *To:* Dick Jansson-rr *Cc:* Bob Davis; AMSAT Eagle *Subject:* Re: [eagle] Revised Module Suggestion
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Chuck,
I think there is a good chance that the IHU will be redesigned for Eagle. We are discussing some important changes like switching to an open core instead of the ARM core, changing the oscillator design, and other improvements. If that is done it will be a modest leap to a new board size.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: eagle-bounces@amsat.org [mailto:eagle-bounces@amsat.org] On Behalf Of Chuck Green Sent: Tuesday, October 16, 2007 11:15 AM To: Dick Jansson-rr Cc: 'AMSAT Eagle' Subject: [eagle] Re: Revised Module Suggestion
Hi Dick,
When considering special needs, don't forget that the IHU has already been designed and will need a box to accommodate it. You did this once, but with the new box designs, it may need to be done again.
Chuck
Dick Jansson-rr wrote:
Juan:
There is another issue that comes to mind regarding "specialized" modules. In a program such as Eagle we will need to create an acceptable module design that is useful for many applications in the mission and then turn on the fabrication machinery for producing these long before the electronic forces are ready to populate them for flight. On P3D in 1992-3 we gambled and manufactured a very many module parts, expecting that we would have some spares left over - wrong! Even with this quite large quantity of parts (and at that time there was criticism that we were making too many) we ran out before flight and had to make some more.
Fabricating module parts for this program is a guessing game, with some estimates of needing to construct up to 80 sets of parts, and that may not be enough. You can do the detailed program mathematics and come up with some number and I will be willing to bet that you end up on the wrong side of that guess. It's a dicey game.
The lesson in this is that we must create a generic module design and hardware that can be adapted for many different assignments in the spacecraft. Save for your specialized need, we have no indication of any other specialized module needs. This is why I prefer to adapt a generic module to your needs with the added heat sinks, rather than make just a specially machined device just for your needs. And if we do, we will probably not have enough of them. This is why I prefer to have a generic module design and then carefully adapt it as required for specialized module needs. We will be flying more than just the U receiver!.
'73,
Dick Jansson, KD1K
kd1k@amsat.org mailto:kd1k@amsat.org
kd1k@arrl.net mailto:kd1k@arrl.net
*From:* wa6htp@gmail.com [mailto:wa6htp@gmail.com] *On Behalf Of *Juan Rivera *Sent:* Monday, 15 October, 2007 15.38 *To:* Dick Jansson-rr *Cc:* Bob Davis; AMSAT Eagle *Subject:* Re: [eagle] Revised Module Suggestion
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
_______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Hi Rick,
That's news to me. What is this secret group you called "We" and when do they intend to include the rest of the Eagle community? Also, where should I ship the parts that were purchased for the IHU? The developers of this new IHU may be able to use some of them.
Chuck
Rick Hambly (W2GPS) wrote:
Chuck,
I think there is a good chance that the IHU will be redesigned for Eagle. We are discussing some important changes like switching to an open core instead of the ARM core, changing the oscillator design, and other improvements. If that is done it will be a modest leap to a new board size.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: eagle-bounces@amsat.org [mailto:eagle-bounces@amsat.org] On Behalf Of Chuck Green Sent: Tuesday, October 16, 2007 11:15 AM To: Dick Jansson-rr Cc: 'AMSAT Eagle' Subject: [eagle] Re: Revised Module Suggestion
Hi Dick,
When considering special needs, don't forget that the IHU has already been designed and will need a box to accommodate it. You did this once, but with the new box designs, it may need to be done again.
Chuck
Dick Jansson-rr wrote:
Juan:
There is another issue that comes to mind regarding "specialized" modules. In a program such as Eagle we will need to create an acceptable module design that is useful for many applications in the mission and then turn on the fabrication machinery for producing these long before the electronic forces are ready to populate them for flight. On P3D in 1992-3 we gambled and manufactured a very many module parts, expecting that we would have some spares left over - wrong! Even with this quite large quantity of parts (and at that time there was criticism that we were making too many) we ran out before flight and had to make some more.
Fabricating module parts for this program is a guessing game, with some estimates of needing to construct up to 80 sets of parts, and that may not be enough. You can do the detailed program mathematics and come up with some number and I will be willing to bet that you end up on the wrong side of that guess. It's a dicey game.
The lesson in this is that we must create a generic module design and hardware that can be adapted for many different assignments in the spacecraft. Save for your specialized need, we have no indication of any other specialized module needs. This is why I prefer to adapt a generic module to your needs with the added heat sinks, rather than make just a specially machined device just for your needs. And if we do, we will probably not have enough of them. This is why I prefer to have a generic module design and then carefully adapt it as required for specialized module needs. We will be flying more than just the U receiver!.
'73,
Dick Jansson, KD1K
kd1k@amsat.org mailto:kd1k@amsat.org
kd1k@arrl.net mailto:kd1k@arrl.net
*From:* wa6htp@gmail.com [mailto:wa6htp@gmail.com] *On Behalf Of *Juan Rivera *Sent:* Monday, 15 October, 2007 15.38 *To:* Dick Jansson-rr *Cc:* Bob Davis; AMSAT Eagle *Subject:* Re: [eagle] Revised Module Suggestion
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Hi Chuck,
Yah - what happened to all this talk of "openess" in the Eagle design endeavor??
Bill - N6GHz
Chuck Green wrote:
Hi Rick,
That's news to me. What is this secret group you called "We" and when do they intend to include the rest of the Eagle community? Also, where should I ship the parts that were purchased for the IHU? The developers of this new IHU may be able to use some of them.
Chuck
Rick Hambly (W2GPS) wrote:
Chuck,
I think there is a good chance that the IHU will be redesigned for Eagle. We are discussing some important changes like switching to an open core instead of the ARM core, changing the oscillator design, and other improvements. If that is done it will be a modest leap to a new board size.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: eagle-bounces@amsat.org [mailto:eagle-bounces@amsat.org] On Behalf Of Chuck Green Sent: Tuesday, October 16, 2007 11:15 AM To: Dick Jansson-rr Cc: 'AMSAT Eagle' Subject: [eagle] Re: Revised Module Suggestion
Hi Dick,
When considering special needs, don't forget that the IHU has already been designed and will need a box to accommodate it. You did this once, but with the new box designs, it may need to be done again.
Chuck
Dick Jansson-rr wrote:
Juan:
There is another issue that comes to mind regarding "specialized" modules. In a program such as Eagle we will need to create an acceptable module design that is useful for many applications in the mission and then turn on the fabrication machinery for producing these long before the electronic forces are ready to populate them for flight. On P3D in 1992-3 we gambled and manufactured a very many module parts, expecting that we would have some spares left over - wrong! Even with this quite large quantity of parts (and at that time there was criticism that we were making too many) we ran out before flight and had to make some more.
Fabricating module parts for this program is a guessing game, with some estimates of needing to construct up to 80 sets of parts, and that may not be enough. You can do the detailed program mathematics and come up with some number and I will be willing to bet that you end up on the wrong side of that guess. It's a dicey game.
The lesson in this is that we must create a generic module design and hardware that can be adapted for many different assignments in the spacecraft. Save for your specialized need, we have no indication of any other specialized module needs. This is why I prefer to adapt a generic module to your needs with the added heat sinks, rather than make just a specially machined device just for your needs. And if we do, we will probably not have enough of them. This is why I prefer to have a generic module design and then carefully adapt it as required for specialized module needs. We will be flying more than just the U receiver!.
'73,
Dick Jansson, KD1K
kd1k@amsat.org mailto:kd1k@amsat.org
kd1k@arrl.net mailto:kd1k@arrl.net
*From:* wa6htp@gmail.com [mailto:wa6htp@gmail.com] *On Behalf Of *Juan Rivera *Sent:* Monday, 15 October, 2007 15.38 *To:* Dick Jansson-rr *Cc:* Bob Davis; AMSAT Eagle *Subject:* Re: [eagle] Revised Module Suggestion
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
The Eagle design has been the most open in the history of AMSAT.
As we all know, there are certain limitations to who can discuss what with whom due to the way our governement views spacecraft and related technology. So, if certain parties make an observation to certain other parties, this information has to be distilled and then shared in mandated ways. This may result in some lag before the larger community is generally aware of such information.
Further, if two or three members of the Eagle team have a beer and discuss certain things, and they have not come to any well-defined suggestions, it is not being "closed" to continue to discuss (maybe over another beer) before floating the idea(s) to the group.
We are all in this together, we are partner-volunteers trying to create a significant technical resource, and we need to always give one another the benefit of the doubt and attribute only the highest and best possible reasons for any particular event.
I choose to not believe anyone is deliberately trying to hide anything from anyone else. Further, if I get a phone call and discuss something or field a question, I don't necessarily feel obligated to transcribe (or even summarize) the conversation and report it here.
I know, and I think everyone else does (if not, they do now) that IHU-3 development has been stalled for a while for various reasons. I am the guy most at fault for this delay. Bob, Rick and others are looking at ways to get it moving forward again. I don't think Rick was announcing a major change to the IHU-3 as some secret conclave's conclusions. He simply mentioned that some aspects of it are being thought about by some members of the team in the context of the larger issues surrounding it. His mention of the fact that this is being thought about is *sharing* -- not hiding.
I saw no specific proposal, nor did I get the impression that there is a specific proposal being hidden.
This is a hobby, guys.
Let's have fun!
73,
Lyle KK7P
Hi Lyle,
I appreciated your response to my terse post. Perhaps my very brief comments reflect my frustration in what has been (from where I sit) a grindingly slow year lacking in "visible" progress on Eagle development - expect for the fine work being done by Juan Rivera and his team with John Stephensen and recently Dick Jansson.
But regarding you comments about technical discussions over a beer, I must bring up a 5/28/07 'Eagle" post from Bob McGweir-----"
I agree with Tom's sentiment and I gave the old "Bob can be a jerk" stomping to private conversation's on Eagle technical matters off list. It ends NOW. We discuss project technical matters here, from the beginning to the end. Personnel issues are to be dealt with privately with/by the project manager and NEVER on this list.
There are many who are on this list who have lots of experience in building these packages for spacecraft. We need the benefit of all of their experience.
Bob"
I'm hoping we are following Bob's post. I just think it's appropriate that when technical discussions over a beer appear to become a consensus especially among two or more Board members and other Eagle team members, that can appear to be an "ad hoc committee" whose opinions and weight of authority can easily become a course of action without getting the opportunity for "other" inputs.
You also say " we all know, there are certain limitations to who can discuss what with whom due to the way our governement views spacecraft and related technology." well I certainly don't know what these are.
I know management has been working on ITAR issues but I haven't heard anything about it since June 07. I think it would be very appropriate for the results (if any are available) of those discussions to be made available with "guidelines" distributed to the uninformed as to what it all means us. In my discussions with associates worldwide about technical issues (not directly Eagle related), I would hate to ignorantly stub my toe on ITAR/AMSAT issues.
Regards...Bill - N6GHz
lyle johnson wrote:
The Eagle design has been the most open in the history of AMSAT.
As we all know, there are certain limitations to who can discuss what with whom due to the way our governement views spacecraft and related technology. So, if certain parties make an observation to certain other parties, this information has to be distilled and then shared in mandated ways. This may result in some lag before the larger community is generally aware of such information.
Further, if two or three members of the Eagle team have a beer and discuss certain things, and they have not come to any well-defined suggestions, it is not being "closed" to continue to discuss (maybe over another beer) before floating the idea(s) to the group.
We are all in this together, we are partner-volunteers trying to create a significant technical resource, and we need to always give one another the benefit of the doubt and attribute only the highest and best possible reasons for any particular event.
I choose to not believe anyone is deliberately trying to hide anything from anyone else. Further, if I get a phone call and discuss something or field a question, I don't necessarily feel obligated to transcribe (or even summarize) the conversation and report it here.
I know, and I think everyone else does (if not, they do now) that IHU-3 development has been stalled for a while for various reasons. I am the guy most at fault for this delay. Bob, Rick and others are looking at ways to get it moving forward again. I don't think Rick was announcing a major change to the IHU-3 as some secret conclave's conclusions. He simply mentioned that some aspects of it are being thought about by some members of the team in the context of the larger issues surrounding it. His mention of the fact that this is being thought about is *sharing* -- not hiding.
I saw no specific proposal, nor did I get the impression that there is a specific proposal being hidden.
This is a hobby, guys.
Let's have fun!
73,
Lyle KK7P
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Lyle,
Thank you. You are exactly correct.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: eagle-bounces@amsat.org [mailto:eagle-bounces@amsat.org] On Behalf Of lyle johnson Sent: Tuesday, October 16, 2007 12:33 PM To: 'AMSAT Eagle' Subject: [eagle] Re: Revised Module Suggestion
The Eagle design has been the most open in the history of AMSAT.
As we all know, there are certain limitations to who can discuss what with whom due to the way our governement views spacecraft and related technology.
So, if certain parties make an observation to certain other parties, this information has to be distilled and then shared in mandated ways. This may
result in some lag before the larger community is generally aware of such information.
Further, if two or three members of the Eagle team have a beer and discuss certain things, and they have not come to any well-defined suggestions, it is not being "closed" to continue to discuss (maybe over another beer) before floating the idea(s) to the group.
We are all in this together, we are partner-volunteers trying to create a significant technical resource, and we need to always give one another the benefit of the doubt and attribute only the highest and best possible reasons for any particular event.
I choose to not believe anyone is deliberately trying to hide anything from anyone else. Further, if I get a phone call and discuss something or field a question, I don't necessarily feel obligated to transcribe (or even summarize) the conversation and report it here.
I know, and I think everyone else does (if not, they do now) that IHU-3 development has been stalled for a while for various reasons. I am the guy most at fault for this delay. Bob, Rick and others are looking at ways to get it moving forward again. I don't think Rick was announcing a major change to the IHU-3 as some secret conclave's conclusions. He simply mentioned that some aspects of it are being thought about by some members of the team in the context of the larger issues surrounding it. His mention of the fact that this is being thought about is *sharing* -- not hiding.
I saw no specific proposal, nor did I get the impression that there is a specific proposal being hidden.
This is a hobby, guys.
Let's have fun!
73,
Lyle KK7P
_______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
While I would have preferred a different route for this discussion to have been joined, it is timely. I have suggested that we do not have the right computer for our new possible mission. We are pushing on the new opportunity with all our might. It does not make sense in any way to fly the IHU-3 with IPS on it since there is no reason whatsoever to have real time control of the possible new mission package. We need the simplest kind of computer that we believe will control the packages, conduct communications with contro, and last for 15 years.
That said, there is nothing that changes in our need for the IHU-3. We are committed to bringing them to the table for P3E and should we fly a satellite, stand alone, it is likely to be needed there. I am going to arrange to have the IHU-3's built incorporating the changes/mods we have learned about from others. Lyle and I have discussed this and I have promised him I would have them built.
For the future:
I am actually even suggesting that we are near the end of life on our ability to build these kinds of devices in our basements/shops and get them reliable enough with a high enough yield to be useful. I am suggesting that if a cool head takes a long hard look at where we are, where the parts are, and what resources we have, that we are likely to decide we are better off having our people do the designs and then having the boards manufactured for us. The price has fallen so far on set up charge and building that this probably makes sense. I am not mandating this, I am suggesting that we should investigate this.
I have suggested that if we fly our own core in a fully qualified rad hard FPGA, there are OPEN CORES for processors. We can easily modify these cores to have fully EDAC registers and memory on chip for cache and off chip memory can be the slow EDAC we know about. In other words, time has marched on, and there is no reason we should not investigate whether we should not move on as well. These cores are available TODAY in the opencores.org group. We should look.
Bob
Rick Hambly (W2GPS) wrote:
Lyle,
Thank you. You are exactly correct.
Rick W2GPS AMSAT LM2232
Hi Bob,
I've had two experiences with having things built for AMSAT. In one case, I was very disappointed with the parts placement precision. I'd like to think that was just the result of a poor choice of vendors. In both cases I found the amount of solder on most joints to be less than I would want to fly so I added solder to every joint. But having the parts already in place saved me a *lot* of time.
Chuck
Robert McGwier wrote:
While I would have preferred a different route for this discussion to have been joined, it is timely. I have suggested that we do not have the right computer for our new possible mission. We are pushing on the new opportunity with all our might. It does not make sense in any way to fly the IHU-3 with IPS on it since there is no reason whatsoever to have real time control of the possible new mission package. We need the simplest kind of computer that we believe will control the packages, conduct communications with contro, and last for 15 years.
That said, there is nothing that changes in our need for the IHU-3. We are committed to bringing them to the table for P3E and should we fly a satellite, stand alone, it is likely to be needed there. I am going to arrange to have the IHU-3's built incorporating the changes/mods we have learned about from others. Lyle and I have discussed this and I have promised him I would have them built.
For the future:
I am actually even suggesting that we are near the end of life on our ability to build these kinds of devices in our basements/shops and get them reliable enough with a high enough yield to be useful. I am suggesting that if a cool head takes a long hard look at where we are, where the parts are, and what resources we have, that we are likely to decide we are better off having our people do the designs and then having the boards manufactured for us. The price has fallen so far on set up charge and building that this probably makes sense. I am not mandating this, I am suggesting that we should investigate this.
I have suggested that if we fly our own core in a fully qualified rad hard FPGA, there are OPEN CORES for processors. We can easily modify these cores to have fully EDAC registers and memory on chip for cache and off chip memory can be the slow EDAC we know about. In other words, time has marched on, and there is no reason we should not investigate whether we should not move on as well. These cores are available TODAY in the opencores.org group. We should look.
Bob
Rick Hambly (W2GPS) wrote:
Lyle,
Thank you. You are exactly correct.
Rick W2GPS AMSAT LM2232
I am actually even suggesting that we are near the end of life on our ability to build these kinds of devices in our basements/shops and get them reliable enough with a high enough yield to be useful. I am suggesting that if a cool head takes a long hard look at where we are, where the parts are, and what resources we have, that we are likely to decide we are better off having our people do the designs and then having the boards manufactured for us. The price has fallen so far on set up charge and building that this probably makes sense. I am not mandating this, I am suggesting that we should investigate this.
I could not agree more. There is no more need to solder the boards ourselves than there is to etch them in our bathtubs.
I have suggested that if we fly our own core in a fully qualified rad hard FPGA, there are OPEN CORES for processors. We can easily modify these cores to have fully EDAC registers and memory on chip for cache and off chip memory can be the slow EDAC we know about. In other words, time has marched on, and there is no reason we should not investigate whether we should not move on as well. These cores are available TODAY in the opencores.org group. We should look.
Again agreed. Also look at:
http://www.gaisler.com/cms/index.php?option=com_content&task=section&...
Which is company that has released a couple of SPARC compliant cores. They have been put into real products and into space. The rad hardened versions (ECC, etc.) are not free, but they may allow us to use them in return for space performance data.
Matt
Some of the PCB manufacturers are selling assembly services for prototype quantities if you supply a centroid file for parts placement. Mounting a BGA costs $50 but they do X-ray the result and we can't do that at home.
73,
John KD6OZH
----- Original Message ----- From: "Robert McGwier" rwmcgwier@gmail.com To: "'AMSAT Eagle'" eagle@amsat.org Sent: Tuesday, October 16, 2007 22:19 UTC Subject: [eagle] Re: Revised Module Suggestion
While I would have preferred a different route for this discussion to have been joined, it is timely. I have suggested that we do not have the right computer for our new possible mission. We are pushing on the new opportunity with all our might. It does not make sense in any way to fly the IHU-3 with IPS on it since there is no reason whatsoever to have real time control of the possible new mission package. We need the simplest kind of computer that we believe will control the packages, conduct communications with contro, and last for 15 years.
That said, there is nothing that changes in our need for the IHU-3. We are committed to bringing them to the table for P3E and should we fly a satellite, stand alone, it is likely to be needed there. I am going to arrange to have the IHU-3's built incorporating the changes/mods we have learned about from others. Lyle and I have discussed this and I have promised him I would have them built.
For the future:
I am actually even suggesting that we are near the end of life on our ability to build these kinds of devices in our basements/shops and get them reliable enough with a high enough yield to be useful. I am suggesting that if a cool head takes a long hard look at where we are, where the parts are, and what resources we have, that we are likely to decide we are better off having our people do the designs and then having the boards manufactured for us. The price has fallen so far on set up charge and building that this probably makes sense. I am not mandating this, I am suggesting that we should investigate this.
I have suggested that if we fly our own core in a fully qualified rad hard FPGA, there are OPEN CORES for processors. We can easily modify these cores to have fully EDAC registers and memory on chip for cache and off chip memory can be the slow EDAC we know about. In other words, time has marched on, and there is no reason we should not investigate whether we should not move on as well. These cores are available TODAY in the opencores.org group. We should look.
Bob
Rick Hambly (W2GPS) wrote:
Lyle,
Thank you. You are exactly correct.
Rick W2GPS AMSAT LM2232
Chuck,
Don't be too concerned, just yet. I just thought it might be wise to say this now, in public. The whole point is that there are no more private "we" groups. Everything is in the open.
The justification for a possible IHU redesign is based on three issues: 1) the present problems with the P3E IHU-3 boards, 2) a desire to move to an open source core so that we can redesign the registers to achieve better radiation resistance, and 3) to move toward an open source operating system like a real time Linux variant, for example.
Right now these are just discussions but I think there is enough justification in them to suggest we not spend time and money creating a special package for the current board just jet. This is just my opinion, not an edict.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: Chuck Green [mailto:greencl@mindspring.com] Sent: Tuesday, October 16, 2007 11:38 AM To: Rick Hambly (W2GPS) Cc: 'AMSAT Eagle'; 'Dick Jansson-rr' Subject: Re: [eagle] Re: Revised Module Suggestion
Hi Rick,
That's news to me. What is this secret group you called "We" and when do they intend to include the rest of the Eagle community? Also, where should I ship the parts that were purchased for the IHU? The developers of this new IHU may be able to use some of them.
Chuck
Rick Hambly (W2GPS) wrote:
Chuck,
I think there is a good chance that the IHU will be redesigned for Eagle.
We
are discussing some important changes like switching to an open core
instead
of the ARM core, changing the oscillator design, and other improvements.
If
that is done it will be a modest leap to a new board size.
Rick W2GPS AMSAT LM2232
-----Original Message----- From: eagle-bounces@amsat.org [mailto:eagle-bounces@amsat.org] On Behalf
Of
Chuck Green Sent: Tuesday, October 16, 2007 11:15 AM To: Dick Jansson-rr Cc: 'AMSAT Eagle' Subject: [eagle] Re: Revised Module Suggestion
Hi Dick,
When considering special needs, don't forget that the IHU has already been designed and will need a box to accommodate it. You did this once, but with the new box designs, it may need to be done again.
Chuck
Dick Jansson-rr wrote:
Juan:
There is another issue that comes to mind regarding "specialized" modules. In a program such as Eagle we will need to create an acceptable module design that is useful for many applications in the mission and then turn on the fabrication machinery for producing these long before the electronic forces are ready to populate them for flight. On P3D in 1992-3 we gambled and manufactured a very many module parts, expecting that we would have some spares left over - wrong! Even with this quite large quantity of parts (and at that time there was criticism that we were making too many) we ran out before flight and had to make some more.
Fabricating module parts for this program is a guessing game, with some estimates of needing to construct up to 80 sets of parts, and that may not be enough. You can do the detailed program mathematics and come up with some number and I will be willing to bet that you end up on the wrong side of that guess. It's a dicey game.
The lesson in this is that we must create a generic module design and hardware that can be adapted for many different assignments in the spacecraft. Save for your specialized need, we have no indication of any other specialized module needs. This is why I prefer to adapt a generic module to your needs with the added heat sinks, rather than make just a specially machined device just for your needs. And if we do, we will probably not have enough of them. This is why I prefer to have a generic module design and then carefully adapt it as required for specialized module needs. We will be flying more than just the U receiver!.
'73,
Dick Jansson, KD1K
kd1k@amsat.org mailto:kd1k@amsat.org
kd1k@arrl.net mailto:kd1k@arrl.net
*From:* wa6htp@gmail.com [mailto:wa6htp@gmail.com] *On Behalf Of *Juan Rivera *Sent:* Monday, 15 October, 2007 15.38 *To:* Dick Jansson-rr *Cc:* Bob Davis; AMSAT Eagle *Subject:* Re: [eagle] Revised Module Suggestion
Dick,
That looks nice! It appears to solve the issue of getting that front panel at exactly 90 degrees to the baseplate and also increases the stiffness of the baseplate. Increasing the useful front panel space also eases the problem of working around the CAN-Do PCB with all of the necessary I/O connectors.
Would it be possible to customize the baseplate for the few modules that draw high power? It would be nice to machine the baseplate and heat sinks as one chunk of metal instead of the existing method of having several individual heat sink pieces. I would like to see the PCB laying flat on top of the baseplate with milled cutouts to accommodate any devices attached to the bottom side. In a perfect world there would be no components on the bottom and the PCB would make contact with the baseplate across the entire surface. Another possibility that might be worth considering would be the ability to include "U" shaped heat sinks that would bridge over the top side of hot components and attach to the baseplate through holes cut into the PCB on either side of the component. Thermal gap filler could allow room for CTE mismatches so that the device isn't crushed.
73, Juan - WA6HTP
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
On Tue, 2007-10-16 at 14:01 -0400, Rick Hambly (W2GPS) wrote:
- to move toward an open source operating system like a real time Linux
variant, for example.
Just for the record, and not because I'm trying to disagree with you, I'll note in passing that IPS is open source, and Karl and the other key European developers agreed with the idea of explicitly licensing IPS under GPL version 2 when I asked about it in the context of a discussion about packaging IPS for Linux a couple of years ago.
Bdale
My apologies. IPS-32 is open source now and my running version of IPS-32 is available for download on the Eagle Wikipedia. I mistyped. I should have expressed my thoughts about the unsuitability of the IHU-3 and IPS and what kind of CPU/control strategy we should use on a geostationary RF package where we have absolutely nothing to control but the RF differently.
IPS is still one of the great pieces of work in computer science of that particular era and never let it be thought that I am not an admirer of Karl's work there. It just is not suitable for an environment where we have gobs of power, lots of communications bandwidth, and absolutely no need whatsoever for real time control. We should use something that more people can help with and understand because there is no need for the terse expression of logic/math/etc that is inherent in IPS.
Bob
Bdale Garbee wrote:
On Tue, 2007-10-16 at 14:01 -0400, Rick Hambly (W2GPS) wrote:
- to move toward an open source operating system like a real time Linux
variant, for example.
Just for the record, and not because I'm trying to disagree with you, I'll note in passing that IPS is open source, and Karl and the other key European developers agreed with the idea of explicitly licensing IPS under GPL version 2 when I asked about it in the context of a discussion about packaging IPS for Linux a couple of years ago.
Bdale
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
On Fri, 2007-10-19 at 08:35 -0400, Robert McGwier wrote:
We should use something that more people can help with and understand because there is no need for the terse expression of logic/math/etc that is inherent in IPS.
I agree.
Bdale
participants (10)
-
Bdale Garbee -
Bill Ress -
Chuck Green -
Dick Jansson-rr -
John B. Stephensen -
Juan Rivera -
lyle johnson -
Matt Ettus -
Rick Hambly (W2GPS) -
Robert McGwier