Beagle ... alas

OM wrote:
On Sun, 28 Dec 2003 06:35:04 -0700, Charles Buckley
wrote:


The work could easily be done by an embedded 386 CPU now,
which I believe is priced in the $10-$20 range. A quick poke around
and I am actually having a hard time finding just the CPU available
anywhere. The standard purchase unit seems to be a PC/104 with
all the trimmings


...I have a 386 sitting in my desk drawer, still in the antistat
casing. If NASA wants it for a Shuttle upgrade, I'll gladly donate it
and skip the tax writeoff.

OM


Well, the main problem with a 386 and Intel in general
was the number of IRQ's, IIRC. You'd have to design the
system around those limitations, which means a 386 would
work fine in anything else, but it is incompatible with
the basic design concepts of the Shuttle computer. You
could design something new into orbit using a 386, but
back engineering is basically impossible, especially when there
is no possibility of porting code.

In article ,
says...
While there are still applications that are
strictly tailored to low power, it is by no means the way all
electronics are being designed.

An example is the early DEC Alpha chips. These designs were optimized
for speed at all costs, so they are quite power hungry. The IC with the
CPU draws 10 amps continuously, with a peak of 50 amps. (Yes, heat
dissipation was a serious issue.)
--
Kevin Willoughby lid

Imagine that, a FROG ON-OFF switch, hardly the work
for test pilots. -- Mike Collins

In article ,
says...
While there are still applications that are
strictly tailored to low power, it is by no means the way all
electronics are being designed.

An example is the early DEC Alpha chips. These designs were optimized
for speed at all costs, so they are quite power hungry. The IC with the
CPU draws 10 amps continuously, with a peak of 50 amps. (Yes, heat
dissipation was a serious issue.)
--
Kevin Willoughby lid

Imagine that, a FROG ON-OFF switch, hardly the work
for test pilots. -- Mike Collins

Chris Jones wrote in message ...
(Henry Spencer) writes:

In the two decades before Mars Pathfinder and Mars Global Surveyor, the US
flew a total of one Mars mission -- the Mars Observer megaprobe, a
complete failure.

Hey, they got one picture (at least). But yeah, complete failure is
accurate.

MO wasn't a megaprobe in the same way as some others, though, I think
you'll agree.
[snip]

The key here is the budget, time frame, organization,
management, and design. None of these were terribly
different from other megaprobe projects, in degree
perhaps, but not in substance. By all accounts it
was a megaprobe. By budget alone, and especially by
soaking up the entirety of the Mars mission budget
for said "really, really effing long time!" it is by
definition a megaprobe.

Chris Jones wrote in message ...
(Henry Spencer) writes:

In the two decades before Mars Pathfinder and Mars Global Surveyor, the US
flew a total of one Mars mission -- the Mars Observer megaprobe, a
complete failure.

Hey, they got one picture (at least). But yeah, complete failure is
accurate.

MO wasn't a megaprobe in the same way as some others, though, I think
you'll agree.
[snip]

The key here is the budget, time frame, organization,
management, and design. None of these were terribly
different from other megaprobe projects, in degree
perhaps, but not in substance. By all accounts it
was a megaprobe. By budget alone, and especially by
soaking up the entirety of the Mars mission budget
for said "really, really effing long time!" it is by
definition a megaprobe.

In article ,
Charles Buckley wrote:
Someone went overboard with trying to cram items into the second
generation vehicles. That is not uncommon. It is a generally accepted
fact in the building industry that the second house that someone
builds is their worst house as they try to do too much for what they
have. The first house is always conservative. It's the second when
they think they know what they are doing that they go overboard...

The software business has a name for this: "Second System Effect". Same
principle. Quite a few nightmares of software complexity have been the
designers' second try at a system of that type.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

In article ,
Charles Buckley wrote:
Someone went overboard with trying to cram items into the second
generation vehicles. That is not uncommon. It is a generally accepted
fact in the building industry that the second house that someone
builds is their worst house as they try to do too much for what they
have. The first house is always conservative. It's the second when
they think they know what they are doing that they go overboard...

The software business has a name for this: "Second System Effect". Same
principle. Quite a few nightmares of software complexity have been the
designers' second try at a system of that type.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

"Mary Shafer" wrote in message
...
I'd stop
bringing in homemade goodies, like sticky rolls, if they did. Being a
good baker confers a certain immunity.

There's a reason why the folks that handle state land auctions go out of
their way for my family- baked goods, especially made-from-scratch. Almost
every time I visit, I bring bread, cookies or brownies.
--
If you have had problems with Illinois Student Assistance Commission (ISAC),
please contact shredder at bellsouth dot net. There may be a class-action
lawsuit
in the works.

"Mary Shafer" wrote in message
...
I'd stop
bringing in homemade goodies, like sticky rolls, if they did. Being a
good baker confers a certain immunity.

There's a reason why the folks that handle state land auctions go out of
their way for my family- baked goods, especially made-from-scratch. Almost
every time I visit, I bring bread, cookies or brownies.
--
If you have had problems with Illinois Student Assistance Commission (ISAC),
please contact shredder at bellsouth dot net. There may be a class-action
lawsuit
in the works.

Henry Spencer wrote:

Someone went overboard with trying to cram items into the second
generation vehicles. That is not uncommon. It is a generally accepted
fact in the building industry that the second house that someone
builds is their worst house as they try to do too much for what they
have. The first house is always conservative. It's the second when
they think they know what they are doing that they go overboard...



The software business has a name for this: "Second System Effect". Same
principle. Quite a few nightmares of software complexity have been the
designers' second try at a system of that type.


On the other hand, there are a lot of things that you do on the first
try that don't work as well as you thought they would, and the
experience can lead to improvements in the second attempt- if Lockheed
were to have had the opportunity to build the A-12/SR-71 all over again
(the SR-71 itself incorporating many hard-learned lessons from the
failed CL-400 "Suntan" project), they would have probably gone with
stainless steel rather than titanium for the aircraft's structure- they
found out the hard way that titanium was nowhere near as easy to work
with as they thought.
In the same way, the Space Shuttle would probably have been quite
differently if we had it to do all over again after years of experience
with he one we have, and it's failings, particularly in the aspects of
design robustness and safety, as well as economy of operation.
If it were redone today, I'd bet it would include either liquid fueled
boosters, or solid fueled ones that were capable of shutdown like the
TitanIII/MOL design; single or multiple escape capsules for the crew
with some sort of heat shielding; and a method of separating the orbiter
from the stack in an emergency. It would probably be larger and heavier
to perform the same mission, but built to be both simpler and tougher;
and designed to require less costly turn-around maintenance.
I grew up in a house that was the first effort by some carpenters at
house building- it had some very peculiar features, including light
switches that did nothing, and others that worked like some sort of
primitive logic device when hooked in pairs (so that turning one on or
off might or might not turn on or off the light in question) and an
internally braced wall that relied upon long rods extending back to
anchor points concealed under the center of the lawn to allow a 12 inch
thick wall- that appeared to be unsupported externally- to contain a
five-foot-deep layer of soil- this worked for a while, but the anchor
rods rusted through after a few decades, and the fact that the dirt
couldn't move outward during the seasonal freezing and thawing meant
that slowly but surely it began to crush the foundation inwards.

Pat