Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_3/V16NO322.TXT

Internet Message Format | 1993-07-13 | 39KB

Date: Wed, 17 Mar 93 05:04:34
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #322
To: Space Digest Readers
Precedence: bulk


Space Digest                Wed, 17 Mar 93       Volume 16 : Issue 322

Today's Topics:
                             1-800-NASA?
                    20Khz Power supplies. (2 msgs)
                   Cancel wars and academic freedom
                          EMCONJ.FLI problem
                         Lunar Ice Transport
                            NASA SELECT TV
               Venus and Mars, was Re: TIME HAS INERTIA

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 16 Mar 93 10:47:51 +0600
From: [e-mail]
Subject: 1-800-NASA?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Al Globus) writes:
> The Clinton administration has a new program to find ways to improve
> the government.  Each part of the government has an 800 number to call
> to note problems and suggest solutions.

NASA's Hotline number is 1-800-424-9183.

You can use this number to report fraud, to register
opinions, or to suggest new projects for NASA.

Tricia Porth
NASA HQ

------------------------------

Date: 16 Mar 1993 11:16:35 -0500
From: Pat <[e-mail]>
Subject: 20Khz Power supplies.
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
|In <[e-mail]> [e-mail] (Pat) writes:
|
|>In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
|>>In <[e-mail]> [e-mail] (Pat) writes:
|>>
|>>>In article <[e-mail]> [e-mail] (David B. Mckissock) writes:
|>>>>In article <[e-mail]>, [e-mail] (Pat) writes...
|
|Nobody said that you said you were there.  The point is that the
|person you are arguing so vehemently with *was*.  Therefore, you are
|arguing *at best* from second-hand rumour against someone with
|first-hand knowledge.
|

Gee,  and when I ask someone who was *There* to justify
blatantly stupid activities,  You start squealing.  Gee fred,
do you have family working on this project?   I'm glad
mcKissock is posting,  but I still have not seen one
quantitative argument from him on defending 3 basic arguments.

|>I don't have to smoke crack to think it's stupid?  why should I
|>have to work at NASA to know this project was out of control.
|
|Given some of the things you say here, I'm not convinced that you *do*
|know that smoking crack is stupid.
|

Gee Fred.  Welcome to the doug mohney school of gratuitios public slurs.

|>|>>relative to the decision. My guess is that your Reston
|>|>>contact was outside the loop on the 20 kHz decisions, and
|>|>>heard spurious rumors.
|>|>><< Discussion attacking 20 kHz deleted >>
|>|
|>|>Not how you avoid a very resaonable discussion on how STUPID
|>|>the 20 KHz idea even was in the first place?
|>|
|
|>NOTE AGAIN:  No-one at NASA or in SSF contract staff has yet
|>to come up with one reasonable discussion supporting the idea
|>of 20Khz power.
|
|I'm not sure why you think they should waste their time making a
|'reasonable discussion' for your benefit, when you obviously think the
|only 'reasonable' discussion is one which agrees with your preformed
|conclusions.
|

Gee Fred.  Several million dollars of MY tax dollars were spent on this
boondoggle.  Why shouldn't they justify this.  It's no different
then if a congress critter asked these questions.

Fred.  why don't you have them answer my quewstion, and I'll shut up.

|>|>Can you name any competent Electrical engineers, or Computer engineers
|>|>or PE's  who thought this was a good idea?
|>|
|>|Gee, Pat, do you think an accountant dreamed it up, or what?
|
|>Yes.  The idea is obviously more oriented at enriching contractors
|>then at producing working systems.
|
|All I can suggest to that is that you need to get out more and find
|out how things really work.
|

Gee Fred.  I live here in DC.  I see how things work everyday.
How do you think they work?  Glorious engineer-heros  working on thin
budgets, boldly exploring the worlds of God's Creation?   I don't
think so.  I see slick lobbyists,  Fat Senators  and venal Executive
branch bureacrats.   DC is a very de-inspiring town to work in.

Fred  as opposed to FRED the cut down space station.  You try to explain
why a totally untested technology would be used on such a critical
project.  Name 3 projects that have used 20Khz  power.  name 3 companies
that produce 20Khz power components.

|>|Obviously there were some engineering folks who thought it *might* be
|>|a good idea, or it would never have been investigated in the first
|>|place.  This is how engineering works, Pat.  You look at various
|>|possible solutions to the problem, analyse the risks, costs, and
|>|benefits, and then you pick the one that seems best overall.
|>|
|
|>Yeah, and look at the decision they picked.   They picked Most Risk,
|>Most Cost, Fewest Benefits.  No-one disputes this.
|
|Well, let us say that no one bothers to dispute it with you.
|

OOh Fred, you are such a clever guy.  You disputed this,  until mean old
pat went and threw mud on your Beautiful Space Station,  Named after you.

The point is 20 KHz power  was most cost, Most risk,  fewest benefits.
No rational engineering project would select this unless there was a
critical design requiremnt to drive this option.  Nobody at NASA has
ever pointed out a Critical requirement that this re-solved.  If there
was no critcality associated with this option,  then the option was
driven by political requirements.

In case anyone noticed,  the SSF people promptly abandoned 20KHz and
went to 28VDC.  it makes one suspect the decisions were solely political
in nature.

|>If the decision making process makes this kind of obvious error,
|>what makes you think they aren't screwing up elsewhere.
|
|What 'decision', Pat?  What kind of power is the Station using?
|
 The 'decision' i was talking about was the 'decision'  to spend
money on a pretty strange idea like 20 Khz power.

|>Engineering is a highly conservative field.   It doesn't do things
|>because it sounds nice,  it does things because it works.  And 20Khz
|>never worked even on paper.
|
|Proof by assertion.  Seems to be your forte.
|

Ah, gee fred,  do you see anything wrong with my 'assertion'.

|
|>|>Given how bad the concept of 20 KHz was,  why do you expect me to believe
|>|>the studies on it's safety.
|>|
|>|Because he was there and you weren't?  This starts to sound more and
|>|more like a "my mind is made up -- don't cloud the issue with facts"
|>|position on your part.
|>|
|
|>And maybe my friend at Reston was "There" and had a manager tell him
|>"Don't worry about the safety study, the station will never fly".
|
|And maybe he wasn't.  You have, at best, second-hand information.  You

Gee fred,  you can't dispute a technical argument so you switch to
the line that I must be lying,  or my friend was lying.  YTou should
have worked for senator McCarthy.

|insist that that is better than someone else's first-hand information
|simply because the first-hand information doesn't support what you
|want to believe.  So why should people bother with 'discussing' things
|with you?

Gee.  I asked for solid things, like  Time factors for safety sensing
relays,  and for weight savings vs  existent power systems.  The problem
was, everytime I'd ask for a hard number,  a large cloud of obfuscation
would arise from  McKissock.

If something is 'Safer' then 400 Hz power,  I'd like to see why it's 'Safer'.
If there isn't a logical physical basis, then  it's a line of crap.
If something is 'lighter' then something else, I'd like to see how
much lighter.

Fred,  do you get hard numbers for your work,  or do you prefer soft fuzzy
statements?

|
|>|>Name 5 advantages to 20 KHz.  I dare you.
|>|
|>|Gee, now *there* is an adult discussion.  Hey, see if you can find
|>|some and broaden your own mind.  I *double* dare you!
|>|
|
|>Here are a few:
|
|>1)  Enrich Boeing, McDac and GD.
|
|>2)  Ensure the astronauts have plenty of work to do replacing
|>    blown out electrical gear.
|
|>3)  Ensure the jobs of a lot of NASA people, because it imposes more
|>    restrictions on the science platforms.
|
|The only appropriate response to the preceding would seem to be
|something along the lines of "Frog Feces!"  Obviously you are too
|intellectually bankrupt to honestly take an adversary position in
|order to really analyze an idea.
|

Gee Fred.  Why don't you take some of your Intellectual small change
down to the bank.  Let's see you defend the idea with solid reasoning.
I'll meanwhile wallow down here in the pond of intellectual poverty.

|>|>Name 5 disadvantages to 20 KHz.  Compare and assess these.
|>|
|>|>Now justify all the money spent on the 20 KHz power project.
|>|
|
|>Note how no-one from NASA or the SSF contractor community dares
|>discuss the engineering decisions on the SSF.
|
|"Dares" to?  Get a clue, Pat.  Given your attitude, I sure wouldn't
|waste my time discussing it with you.  Only reason I'm bothering now
|is because I have a compile running and need to wait for it to finish.
|
Gee fred.  Glad you have such a slow machine.  I don't know whats your
problem.   Did you graduate from the "Feel-nice" school of engineering.
I've worked at places where people were reduced to tears during design
reviews.  If you couldn't produce numbers and solid reasoning for
a review, they'd laugh you out of the room.

I'd still like to see a solid basis for spending on this subject.

|>|
|>|>BIG DEAL.
|>|>The system requirements document.  I've seen requirements documents
|>|>on lots of projects.  ANd if the document is poorly done, it doesn't
|>|>matter.  If the people doing the work don't care about quality
|>|>it doesn't matter.
|>|Once again, you seem to think you know better than someone who was
|>|there and has seen the things.  That's not to say that there aren't
|>|problems; I would say there most certainly are, from what I've seen.
|>|However, I think you'd be better served to address the problems
|>|instead of random flames.

This isn't random flamage.  it's highly directed at 3 issues.
Even wingo commented on that.  But these 3 problems are
syptomatic of basic management problems.  Even goldin gave a
statement that the FRED management team was a shambles.

|>|
|
|>Hey, I have friends there.  And look at skylab.  THey didn't have a
|>"HOLY BIBLE".  They had a chief engineer who was Great, and they
|>had a hard budget and they made the bird fly, in slightly uunder a year.
|
|Yeah, and it wasn't what they originally started out to build, either,
|and it basically got put up as a non-replenishable can in space.
|

And what a can in space it was.  It was way ahead of the russains.
It was fast, cheap, and better then any paper design, cuz it was real.
The principle problem skylab had was there was no cheap way to get
crews and materials up there.  Saturn missions  were expensive.

|>Given the delays on SSF, it is likely SKYLAB will have more flight hours
|>then SSF this century.

Isn't this a sad prospect?

|
|>|>>You obviously don't understand how NASA operates. For the SSF
|>|>>program, NASA has three Contractors responsible for building
|>|>>SSF hardware (McDonnell Douglas, Rocketdyne, and Boeing). A
|>|
|>|>And who is responsible for integrating their work?  How come
|>|>that's a major management issue?
|>|
|>|Bingo!  Real problem #1.
|>|
|
|>And why is it that 10 years into the program, they are finally addressing
|>a vital up-front problem?

Fred, does your silence mean you realize that management was ou;of control
on this issue?

|
|>|
|>|I would say that, in general, no.  Who made a PE ghod?  There are lots
|
|>In general, Judge Wapner.   What most CS people don't understand is that
|>a PE takes LEGAL responsibility for all work done under his stamp.
|
|So nice of you to tell me what "most CS people don't understand".
|Geez, go out and buy a clue, Pat.  I seem to understand more about it
|than you do.  Read on.
|
|>PE's like most other licensed professionals is Criminally responsible
|>for any failures that cause loss of life,  as well as bearing a personal
|>liability for any civil losses.
|
|>PE's have done time for people dying, and many of them are sleepless
|>over things they signed off.   Nobody at NASA or the Contractors is
|>responsible if something fails on SSF.
|
|Yeah?  Name three PE's that this has happened to who didn't
|DELIBERATELY cut a corner or three?  Hell, I'll make it easy; just
|name 3 PE's that this has happened to in the last, oh, 5 years.
|

I will have to do a lexus search on PE's serving time.  I'll get
back to you next week.

|>|of good engineers who simply can't be bothered with it, since it is
|>|only in things like structural engineering that it becomes
|>|particularly meaningful.  I've always found it funny that, except for
|>|stuff that delivers to the government (which follows more reasonable
|>|rules about who is an 'engineer'), I would have to get a PE to sign
|>|off on a software system when there is no such thing as a PE for
|>|software engineering.  What that means is that someone who is
|>|specialized in a different field has to sign off on the software.

|>|Does this strike you as ridiculous?
|>|
|
|>no.  it means someone is willing to lose his license over the quality
|>of your work.  If software is going to be "Engineering"  then it
|>better have standards and ethics, and responsibility.
|
|You mean like the ones that that PE would have to violate in order to
|sign off on work that I did which he cannot ascertain the quality of
|for himself?  Check it out, Pat.  A PE isn't supposed to do that.
|Now, consider the amount of software in *any* modern system and
|consider the fact that there is no such thing as a PE for software.
|How good do you feel now about having to have a PE sign off?
|"Standards and ethics, and responsibility"?  You ever fly, Pat?  Your
|life is hanging by a couple of bits of code.  Ever go to the hospital?
|Ever drive your car?  I'd suggest you find out a bit more about what
|you talk about *before* you talk.  It might make you just slightly

Having been a regular contributor to the risks digest since 1987,
I think i know of the problems in Software quality assurance and
system contingency management.

PE's signing off on software, is stretching the area of the licensee,
but I imagine he is signing off on the whole system,  and that the
whole system has been designed with appropriate design criteria.

What kind of deliverable systems are you having stamped off?


|more credible, and you may even be able to get some real discussion of
|the 20 kHz power issue from someone who knows something about it.
|

So Fred,  Is it your contention that PE's shouldn't sign off
on Electrical systems?   Now that you are done ranting about how
badly you felt having your code signed off on, let's get back to
the question at hand.  I'd like to see a few PE's who think 20Khz
would be better then 400 Hz.

|
|>Sure, I've been through them, and i've also worked on projects where
|>the people just kept puffing smoke as opposed to fixing problems
|>because they wanted to suck off the governments tit.
|>I've taken heat from management for refusing to sign off on
|>smoke requirements checklists.
|
|Well, goody goody for you.  That's how the system works.
|

The project that i was referring to was 5 years over schedule  on
a 2 year project and 500% over budget.  If you think that's how
NASA should work, then you are sad.

|Given your approach, I wouldn't bother either, if I were he.
|
|
|>Gee.  How come my desk lamp is still 60Hz.  That's yesterdays system.
|>But, It Works!  How come my car is a diesel?  It works!  Why are
|>houses still built of wood and stone?  they work!  Engineering is based
|>upon using known solutions.
|>New ideas are extensively tested infield trials before use in production.
|
|Sure it is, Pat.  Gee, that's why you're still using an abacus or
|counting stones instead of a computer, right?  Engineering is *not*
|"based upon using known solutions".  That is called 'heuristic
|reasoning', and it is how all those cathedrals and such got built.

It's also why they are still standing.


|It's also why they fell down several times during construction and
|took so long to build.  How come your desk lamp isn't 60Hz if you're
|in Europe, Pat?  How come my car isn't a diesel?  Funny how you manage
|to forget about things like economics, cost, and past investment in
|all of that talk about how 'engineering' works and why all those
|things are the way they are.
|

Well, gee when I mentioned cost previously, you just sniffed and
pouted.  Cost is actually the big thing i was torked on for the
20Khz power option.  We have a huge investment of knowledge in things as
they are.  New things are brought in when they solve a problem.

What problems were 20Khz power systems solving?

Lots of things are solutions waiting for a problem.  The bosch process
for producing nitrates needed WW1 to get off the shelf.  Fuel cells were
nice until manned space needed lighter weight higher power sources
then batteries.

|>|>    2)  Non Metric (english)  component selection with the
|>|>    european modules being Metric.
|>|
|>|Why should it be metric?  The bulk of the funding is from the United
|>|States of America -- and we're not on the metric system.  Why not just
|>|require everyone else to build non-metric to match the main station?
|>|
|
|>Gee, what a great defense.  It's my bag of marbles, i make the rules,
|>even when my rules are costly and silly,
|
|"Costly and silly"?  It is no more costly *to us* to use English
|measures for the Station.  Why should we have to accomodate the
|smaller partners?  First rule of economics and engineering is the
|Golden Rule, Pat; he who has the gold makes the rules.
|

If we specified all connectors to be English standard, I wouldn't be
so focused on this one.  Or that they all be selected english/metric
interchangably.  Certain metric and english sizes are stock interchangable.

If we had specced out that all things use only this list of connectors,
thread pitches, etc.  I'd be much happier.

I was just pointing out Metric, because it's an international space
station.  English units are the standard in certain things.  space
could be one of them, but it is a political decision.  this
smorgasborg of standards is not conducive to good operations.

Suppose something breaks down.  a line  starts leaking, oxygen.  Now there
is a length of flex hose in the columbus module sufficient to make the
bypass, but OOPS, it has metric connectors, and there are no adapters.

I guess, everyone leaps into the ACRV  and abandons ship.

THe Navy has a whole program now towards connector compatability since
the Stark incident.  The stark tooka missile up-forwards.  The other
ships in the task force went to assist, only there electrical systems
were different, so pumps wouldn't connect to the starks power busses.

One of the real problems in apollo 13 was the LEM life support system
used different modules from that of the CSM.  What was a real butt saver
was the computers were identical.

Do you see anything wrong in maintaining standard connectors and
interfaces and tooling.   Wouldn't it be nice, if some bolt was lost
to not have to hunt around for the right tool, but to know that
standard toolkits will handle the problem.

THe USARMY has the MANPRINT program, where they reduced their connector
and accesory catalog.  Things like the blackhawk were designed to use
only 3?  bolt types for all fittings.  Routine flight service could
be conducted by a mechanic with 1 wrench.

|>And given it's an
|>international station,  we have limited influence on the design of the
|>japanese and european modules.  They do much of their own work.
|>In fact, one of my reston contacts was involved in trying to get the
|>freedom team to switch to metric sizing on fasteners and connectors.
|>management wouldn't allocate a few million dollars to pay for
|>costs for this.
|
|Why should we pay a few million dollars to pay for interconnection
|with stuff we didn't build?  If they want to attach their modules (and
|they do), then they ought to by God follow the interface requirements.
|If that includes English measures, then that's what they're going to
|have to use.
|

But there is no overall engineering standard.  Interfaces are specced
to match,  but individual maodules are not controlled by the master
plan.

One way or another,  someone has to agree to the standard the whole way.
It'd be in our interest to use metric.

Fred,  are you thinking that a few million bucks will break the budget?
It's my feeling that if we went metric, it's be useful for our industries.
The europeans are not interested in manufacturing English unit products.

|
|>Goldin gave a speech this week, he was tired of NASA's existing mentality
|>and of hearing stories of the apollo age.  He said we have to write
|>history not read it.  It also looks like he is inviting the russians
|>to participate in SSF.
|
|Gee, that sure makes ME feel better.  NOT.  That's all we need is
|another partner who may pull out becuase of fiscal problems.  We have
|enough of that problem domestically already.  Hell, if the Russians
|are smart, they'll offer to build and launch the core station for the
|Japanese and European modules to attach to and cut us out completely.
|They'd probably be willing to do it on commission.

That's actually a highly likely scenario.
The MIR2 proposals have an uncanny general similiarity to FRED.
Without some of hte obvious mental problems.   What it looks like
is a CIS/ESA/NASDA station flying by 1997, while we have rusting
modules sitting at Marshall.  And believe me, there will be plenty
of blame to go around if that occurs.

pat

------------------------------

Date: 16 Mar 93 17:48:00 GMT
From: [e-mail]
Subject: 20Khz Power supplies.
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Pat) writes...

[deleted]

>Gee,  and when I ask someone who was *There* to justify
>blatantly stupid activities,  You start squealing.  Gee fred,
>do you have family working on this project?   I'm glad
>mcKissock is posting,  but I still have not seen one
>quantitative argument from him on defending 3 basic arguments.
>

Blatently stupid in your opinion pat. Are you a power engineer?

[more delted]

>Gee Fred.  Several million dollars of MY tax dollars were spent on this
>boondoggle.  Why shouldn't they justify this.  It's no different
>then if a congress critter asked these questions.
>

pat maybe you should go and look at the Lewis Research center budget for
20khz power before you talk about how many millions were wasted. I think
the entire budget was less than one million for the demonstration system.

>Fred.  why don't you have them answer my quewstion, and I'll shut up.
>
>|>|>Can you name any competent Electrical engineers, or Computer engineers
>|>|>or PE's  who thought this was a good idea?

I have been thinking about 20Khz and I can name a few advantages of it, buty
only in its use in space. Well actually here on earth too.

1. 20Khz power is not deadly.  The human body can respond muscularly to
frequencies of up to aroun 800 hz.  This is the primary reason that when
you grab high amperage currents of 60 hz your muscles lock to the power
and you die. With 20 khz this would not happen even if you got hooked to
a direct short.  There are several hundred to thousands of people each year
that die from being muscularly locked to 60 hz or 400 hz power.  This to me
would be an excellent justification for the use of 20 Khz power nationwide.

The problem with 20Khz per se is that some women would not be able to stand
being around it, as a few women can hear frequencies that high. I kinda
doubt this is a problem since many computer monitors also run in this frequenc
domain.

2. Lighter weight tranformers.  This was another reason that 20 Khz was
pushed due to the fact that you could have lighter weight transformers than
would be necessary for a 400 hz system.  With many many experiments, each with
a transformer in the front end of the power supply thous becomes a significant
weight driver.  Pat, many many systems use much higher frequencies to
transform power from one voltage to another.  The MCM 7805 series regulator
that is used by the millions to regulate +5 VDC is actually a 40 Khz chopper
regulator in architecture.  That is the DC voltage is converted to
40 Khz and then rectified to the new lower DC voltage.  The switching
power supply on the PC on your desk uses a similar principle by converting
the 60 hz power from the line to several thousand Khz some in the hundreds of
thousands and then rectifying that down to the DC voltages used in your
computer. Why do this? The transformers are much smaller and lighter. This is
why your switching power supply is a fraction of the size of the old technology
linear supplies.


3. Reliability of the overall system.  How often does the power supply go out
on your desktop PC today? They use the same principle of power supply as was
proposed for SSF by Lewis. There are millions upon million of these supplies
out and operating every day. By far most of them operate at hundreds of
Khz rather than 20 Khz but the prinicple is the same.

>Fred  as opposed to FRED the cut down space station.  You try to explain
>why a totally untested technology would be used on such a critical
>project.  Name 3 projects that have used 20Khz  power.  name 3 companies
>that produce 20Khz power components.
>

Pat Many many compainies use high frequency switching power supplies, most of
them at much higher frequencies than 20 Khz. 20 Khz actually is quite
conservative when it comes to this technology.

1. Power One Located in Camarillo Ca. (AT least that wher they were. Also
open up your PC. They all have switching supplies.

2. Any DC-DC converter manufacturer such as Interpoint (Redmond Wa,)
CALEX, (Cleveland OH?) and many others.

The DC-DC conveter and the great strides that have been made in making this
technology smaller, cheaper, lighter (faster cheaper better) are all totally
dependant upon the principle of changing the DC voltage to a 550 kHz frequency
or higher, rectifying, and then filtering to the desired DC voltage. This is
done at great efficiencies these days (80-90% best case). IT turnes out
that the higher the frequency, the more efficient the process is.  Just seven
years  ago the typical DC-DC conveter was only 60% efficient. This is a great
advance and is leading to changing the whole philosophy of power distribution
within an electronic device.

This new (or actually very old if you remember the S-100 computers) is that
you no longer have a central power supply that provides all of the system
voltages. You take a primary distribution voltage and then locally
regulate to the voltage desired.  This leads to a much simplier power
distribution system, as now you only need one set of wires coming from the
main supply.  This is the philosophy that we are using on SEDSAT 1 and
it is growing in popularity as now the mean time between failure of
DC-DC converter is going over 1,000,000 hours.

>|>|Obviously there were some engineering folks who thought it *might* be
>|>|a good idea, or it would never have been investigated in the first
>|>|place.  This is how engineering works, Pat.  You look at various
>|>|possible solutions to the problem, analyse the risks, costs, and
>|>|benefits, and then you pick the one that seems best overall.
>|>|
>|
>|>Yeah, and look at the decision they picked.   They picked Most Risk,
>|>Most Cost, Fewest Benefits.  No-one disputes this.
>|
>|Well, let us say that no one bothers to dispute it with you.
>|
>
>OOh Fred, you are such a clever guy.  You disputed this,  until mean old
>pat went and threw mud on your Beautiful Space Station,  Named after you.
>
>The point is 20 KHz power  was most cost, Most risk,  fewest benefits.
>No rational engineering project would select this unless there was a
>critical design requiremnt to drive this option.  Nobody at NASA has
>ever pointed out a Critical requirement that this re-solved.

[more tons deleted]

Problems with 20 Khz

1. IF cabin pressure is lost then the system can arc.
2. Non Standard
3. RFI/EMI (can be solved with filters however)

Actually not bad except for #1. If cabin pressure is lost you have to
shut down your power system. No good for system recovery. From what I
remember that is the final reason that 20Khz died.

[literally tons deleted]

>And what a can in space it was.  It was way ahead of the russains.
>It was fast, cheap, and better then any paper design, cuz it was real.
>The principle problem skylab had was there was no cheap way to get
>crews and materials up there.  Saturn missions were expensive.

Saturn 1B flights were pretty cheap actually.
Why pat?

>Fred,  are you thinking that a few million bucks will break the budget?
>It's my feeling that if we went metric, it's be useful for our industries.
>The europeans are not interested in manufacturing English unit products.
>

The Japanese have no problems doing that. Maybe that is why they are ahead
huh. :-)

>|
>|>Goldin gave a speech this week, he was tired of NASA's existing mentality
>|>and of hearing stories of the apollo age.  He said we have to write
>|>history not read it.  It also looks like he is inviting the russians
>|>to participate in SSF.
>pat


Pat I have to apologize to you. I purposely started this thread in order
to prove a point. That unless you are an expert int he field you better keep
you mouth volume to a lower level.  It turns out that  20 Khz is perfectly
justifiable method of primary power distribution. It had an achilles heel
which is its performance under emergency conditions relating to loss
of cabin pressure.  If that could have been solved, it would have been a fairly
good idea, except fo the fact that power technology has advanced so
rapidly that 20 Khz is obsolete.  This is probably the final factor that
brought the end of 20 khz.

Now look at all of the hand waving and screaming that you did in this and
may other posts on this subject.  You posted without doing any research on
the subject and postulated all kinds of dire reasons for the decisions
that were taken.  Please step back a little and reconsider the way that
 you reply to posts like this one on 20 Khz.  For referecne call interpoint
on the advantages of distributed power and go buy a book on power supply
design before you rant about conspiracys in Aerospace welfare.

Dennis, University of Alabama in Huntsville

------------------------------

Date: Tue, 16 Mar 1993 15:46:15 GMT
From: Mike Schenk [phone] <[e-mail]>
Subject: Cancel wars and academic freedom
Newsgroups: alt.privacy,sci.space,sci.astro,comp.org.eff.talk,news.admin.policy

In article <1o2k7i$[e-mail]> [e-mail] writes:
>
>**Warning - strong opinions ahead **
>
>The choice of anonymity or full disclosure of identity is a personal choice.
>How you respond to an anonymous posting is also a personal choice.
>
>However, cancelling someone else's postings, anonymous or otherwise,
>smacks not only of censorship and violation of freedom of speech, but
>also of mail tampering and fraud (since this is done by forging a cancel
>message supposedly by the original poster).
>
>There may not be any laws prohibiting this type of tampering, but there
>should be.  If you do not like what someone posts, or how they say it,
>ignore them or flame them.  If you feel they are deliberately being
>disruptive, notify their administrator.  If an anon poster is apparently
>being deliberately disruptive, make your case to the anon administrator,
>but don't expect you will always have it your way (this also applies to
>notifying the sysadmin of a non-anon nuisance - McElwaine is still around
>after all).
>
>I am disgusted at what some people will do in the name of moral outrage.

Exaclty my point! And once again, if somebody posts anonymously using a
anon server you can still reach that person using email! So you can
still make it clear when you have a problem with a certain posting.
However, without anon servers, people will start using forged From:
headers. You will increase the problem then!

So in my opinion there are two major reasons against the automatice
cancelling. The technical one as stated above and the ethical one as
stated in the previous posting to which this posting is a followup!

    Mike

------------------------------

Date: 16 Mar 93 18:01:22 GMT
From: Greg F Walz Chojnacki <[e-mail]>
Subject: EMCONJ.FLI problem
Newsgroups: sci.space,sci.astro,alt.sci.planetary

I've been having problems running emconj.FLC and magellan.fli with play.exe.
I'm running a trident 8900 w/ 1024k RAM.

Anybody else have this problem -- and SOLVE it?

Thanks.

Greg

------------------------------

Date: Tue, 16 Mar 1993 16:46:11 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Lunar Ice Transport
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Pat) writes:

>Fred talks about accuracy problems in Ballistic delivery due to masscons
>and weight variations.

>I imagine tha tthe  problem is not that difficult.

>First, a highly accurate gravity map would be available,  and this
>would be over a single well known route.

I'm not convinced that such a map would be available.  Simply making
such a map seems like quite an undertaking.

>Second,  the moon is seismically dead, so it won't vary.

>Third.  THere is no atmosphere to foul up flight.

>I imagine loads would be weight and balance checked before launch,
>and may even fly with an emergency trajectory correction package
>for abort purposes.  i.e.  the gun loses power on the final 10%
>of acceleration.

The problem here is twofold.  Any variance in mass distribution of the
load or of power and efficiency of the launcher are going to lead to a
miss.  I think this is a more difficult problem over the distances
being talked about than Pat seems to believe.  'Mere engineering',
perhaps, but that makes it no more tractible.

>Remember, using 18"  cannon,  in atmosphere,  the US navy had a regular
>accuracy of 50 meters in 35 miles.

The U.S. Navy has never had a ship mounting an 18" gun.  The Japanese
had a few (Yamato, et al), but the largest gun on a U.S. ship was and
is 16" on the New Jersey and Missouri BB's.  The range of a 16" gun is
not 35 miles; It is around 40 kilometres or about 23 miles.  Note that
this is not that far over the radar horizon, which is how reasonable
accuracy is achieved.  Fire a shot that should be close, see where it
lands, then make adjustments.

Now do the triginometry to compute what a 50 metre error over a 40
kilometre flight translates to when the range is on the order of 1/4
of the lunar circumference.  The kind of accuracy needed over a flight
of that length is *hard*; midcourse and terminal homing would seem to
be required, unless your 'catcher' is something on the order of a
crater that is lidded over with some sort of flexible 'valve' diaphram
and you can just let the projectiles crash down anywhere within a
circle a couple of hundred metres across -- and even then, it's not an
*easy* problem.

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

------------------------------

Date: Tue, 16 Mar 1993 16:01:19 GMT
From: Dillon Pyron <[e-mail]>
Subject: NASA SELECT TV
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Alan Guggenheim) writes:
>     I would like my cable operator to carry NASA Select.  Does anyone
>know of a good way to convince them to carry it, especially if channels
>are limited?  Is there any convincing info?  If that fails, how much
>does it cost for equipment to pick up the signal directly from a
>satellite?  Where can you purchase this equipment?

If they have limited channels, you may be stuck.  If not, try the following (I
am, and it seems to be working).

Talk to the the cable management.  Impress upon them the added value to
education and the community.

Find sponsors.  I have three people that have indicated they will put in
$100/quarter in exchange for some minor mention.  Not much is needed since the
dish is already pointed at the bird and the cable company doesn't have to pay
for it.

Get community/education support.  In my case, two of my friends teach science
in the local schools.  They have written letters support NASA Select and stated
that they would use it in their classes.

I'll know in June, when they setup the next reprogramming (I started too late
for April, next one is in July).

--
Dillon Pyron                      | The opinions expressed are those of the
TI/DSEG Lewisville VAX Support    | sender unless otherwise stated.
[phone] (when I'm here)     |
[phone] (when I'm home)     |Guns don't kill people, religious cults kill
[e-mail]          |people.  Ban religion, repeal the 1st
PADI DM-54909                     |Ammendment.  That's just as silly!

------------------------------

Date: Tue, 16 Mar 1993 17:38:18 GMT
From: Eric H Seale <[e-mail]>
Subject: Venus and Mars, was Re: TIME HAS INERTIA
Newsgroups: sci.space

[e-mail] (Ata Etemadi) writes:

>Plain old moss loves the constituents
>of the Venus atmosphere, and is highly resistent to attack from UV, acid etc..

Am I missing something, or is there a type of moss that "loves"
water-free growing environments?

Eric Seale
#include <disclaimer.std>

------------------------------

End of Space Digest Volume 16 : Issue 322
------------------------------