Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO591.TXT

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Date: Thu, 24 Dec 92 05:14:19
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #591
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu, 24 Dec 92       Volume 15 : Issue 591

Today's Topics:
                    Acceleration, cats... (2 msgs)
                            Article on DC
                       asteroids beyond Jupiter
                  ASTM, Saturn and MOL (Was Re: MOL)
                 Aurora chase planes (was Re: Aurora)
                           Breeder reactors
                     fast-track failures (2 msgs)
             funding for Lunar Prospector urgently needed
                        Giotto Sample Return ?
                          ground vs. flight
                            LEI financing
MOL (was Re: Terminal Velocity of DCX? (was Re: Shuttle ...)) (4 msgs)
                         satellite costs etc.

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Date: 23 Dec 92 14:27:45 CST
From: Greg Titus <[e-mail]>
Subject: Acceleration, cats...
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Josh 'K' Hopkins) writes:
>[e-mail] ("Phil G. Fraering") writes:
>
>>... some cats have fallen from ten or twenty stories and sometimes
>>survived ...
>
>>What I want to know is, how the ability to fall from 100-150 feet
>>up was _selected for_ by evolution. It implies that they went through
>>a period of development where cats that could do that were outcompeting
>>cats that weren't, to the extent that a large number of cats today can
>>do it.
>
>... you can't blame everything on evolution.  The
>apendix comes to mind.  Some things are around simply because they weren't
>selected against.
>
>...  The test I believe you are
>refering to was studying just why it is that "cats always land on their feet."
>If you toss one of the second story window they don't have time to twist into
>the right position.  A higher fall may sound more dangerous but it gives the
>cat time to get into landing position.  Thus it's actually safer.

Two points ...

Josh, it takes very little altitude for a cat to land on its feet.
Initially positioned with feet upward, both of mine can do it given
three feet of altitude; neither can do it given two feet or less.
(Test performed under humane conditions using a bed as a landing pad.
Both cats rewarded with sardines afterward.)

What Phil was talking about is a separate study to check into some
surprising results regarding height of fall vs. extent of damage to
cats.  This was discussed in (I think) Science News a while back.
Somebody got curious after hearing the report of the cat that fell out
of a 10th (?) story window in San Francisco during the Santa Cruz
earthquake a few years ago, and received minimal damage.

It turns out that cats have a particular muscular/skeletal arrangement
they go into when they enter free fall, which is designed to maximize
the shock absorbance of the whole cat and minimize damage to any
particular part of it.  However, this mode does not work all the way
up to feline terminal velocity, with the result that as fall height
increases past 10 or 15 feet, cats experience more and more damage
upon landing.  Above 30 or 40 feet, they are usually very badly
injured.  However, the tensed-up shock absorbing mode does not last
very long.  If no landing occurs, then the cat begins relaxing, with
the result that a cat falling from 80 to 100 feet lands as a blob, and
often has very minor injuries.

Basically, it turns out that a relaxed cat can impact at feline
terminal velocity without much damage.  The tensed mode reduces the
injury rate to zero for impact velocities below a certain value, but
adversely affects survivability between that point and somewhat less
than terminal velocity.

Although I don't recall the article mentioning it, one hypothesis to
explain this is that there is an acceleration value above which a cat
enters this "shock absorber mode".  As the cat approaches terminal
velocity in a fall the acceleration decreases, perhaps to the point
that the autonomous system that handles impact management decides that
the cat is no longer falling, and lets loose the muscular tension.

Or in other words, it's a bug masquerading as a feature.

I give away my Science News magazines, but perhaps somebody out there
has access to an index for the last couple of years, and could find
the article.

greg
--
--------------------------------------------------------------
Greg Titus ([e-mail])             Compiler Group (Ada)
Cray Research, Inc.                               Santa Fe, NM
Opinions expressed herein (such as they are) are purely my own.

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

Date: 23 Dec 92 20:32:36 GMT
From: Greg Titus <[e-mail]>
Subject: Acceleration, cats...
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Josh 'K' Hopkins) writes:
>[e-mail] ("Phil G. Fraering") writes:
>
>>... some cats have fallen from ten or twenty stories and sometimes
>>survived ...
>
>>What I want to know is, how the ability to fall from 100-150 feet
>>up was _selected for_ by evolution. It implies that they went through
>>a period of development where cats that could do that were outcompeting
>>cats that weren't, to the extent that a large number of cats today can
>>do it.
>
>... you can't blame everything on evolution.  The
>apendix comes to mind.  Some things are around simply because they weren't
>selected against.
>
>...  The test I believe you are
>refering to was studying just why it is that "cats always land on their feet."
>If you toss one of the second story window they don't have time to twist into
>the right position.  A higher fall may sound more dangerous but it gives the
>cat time to get into landing position.  Thus it's actually safer.

Two points ...

Josh, it takes very little altitude for a cat to land on its feet.
Initially positioned with feet upward, both of mine can do it given
three feet of altitude; neither can do it given two feet or less.
(Test performed under humane conditions using a bed as a landing pad.
Both cats rewarded with sardines afterward.)

What Phil was talking about is a separate study to check into some
surprising results regarding height of fall vs. extent of damage to
cats.  This was discussed in (I think) Science News a while back.
Somebody got curious after hearing the report of the cat that fell out
of a 10th (?) story window in San Francisco during the Santa Cruz
earthquake a few years ago, and received minimal damage.

It turns out that cats have a particular muscular/skeletal arrangement
they go into when they enter free fall, which is designed to maximize
the shock absorbance of the whole cat and minimize damage to any
particular part of it.  However, this mode does not work all the way
up to feline terminal velocity, with the result that as fall height
increases past 10 or 15 feet, cats experience more and more damage
upon landing.  Above 30 or 40 feet, they are usually very badly
injured.  However, the tensed-up shock absorbing mode does not last
very long.  If no landing occurs, then the cat begins relaxing, with
the result that a cat falling from 80 to 100 feet lands as a blob, and
often has very minor injuries.

Basically, it turns out that a relaxed cat can impact at feline
terminal velocity without much damage.  The tensed mode reduces the
injury rate to zero for impact velocities below a certain value, but
adversely affects survivability between that point and somewhat less
than terminal velocity.

Although I don't recall the article mentioning it, one hypothesis to
explain this is that there is an acceleration value above which a cat
enters this "shock absorber mode".  As the cat approaches terminal
velocity in a fall the acceleration decreases, perhaps to the point
that the autonomous system that handles impact management decides that
the cat is no longer falling, and lets loose the muscular tension.

Or in other words, it's a bug masquerading as a feature.

I give away my Science News magazines, but perhaps somebody out there
has access to an index for the last couple of years, and could find
the article.

greg
--
--------------------------------------------------------------
Greg Titus ([e-mail])             Compiler Group (Ada)
Cray Research, Inc.                               Santa Fe, NM
Opinions expressed herein (such as they are) are purely my own.

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

Date: 23 Dec 92 20:38:36 GMT
From: Henry Spencer <[e-mail]>
Subject: Article on DC
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Paul Dietz) writes:
>... Can someone explain in more detail Aerojet's
>proposal for the DC-Y, the "integrated modular platelet engine"?

If I'm not mistaken, this was a scheme to build an aerospike engine as
a ring of semi-independent segments, each looking like a flat (well,
slightly curved) plate overall.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Wed, 23 Dec 1992 20:35:36 GMT
From: bill nelson <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: alt.folklore.urban,sci.space

[e-mail] (Greg F Walz Chojnacki) writes:
:
: Although it might seem like I'm paying out rope here, I'm curious about the
: usage of the terms "asteroid" and "planetoid." Bill, since yours is the first
: time I saw the distinction made, care to define these? (I hope it's more than
: asteroids being those things that lie where asteroids were first discovered.)

Nope, that is the distinction I use. Whether it is currently the accepted
definition is another matter. I define an asteroid to be a body that
originated in the asteroid belt - others are planetoids or "minor bodies"
or comets etc.

Flame away, if you wish. My asbestos underwear, while well charred, is still
functional.

Bill

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

Date: Wed, 23 Dec 1992 19:17:40 GMT
From: Gary Hughes - VMS Development <[e-mail]>
Subject: ASTM, Saturn and MOL (Was Re: MOL)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] writes...
>Also I have been doing some sleuthing and have found a few details abou the
>Saturn I series. There is actually three distinct vehicles in the Saturn I
>series. The Saturn C-1 was basically a 2 stage vehicle that used the Centaur
>first generation as its second stage. I do not know yet whether this is the
>six engine configuration Henry talked about or not.
>
>Then there is the Saturn 1. This beast had several changes relative to the C-1.
>This including adding the fins that you see on the televised Saturn 1 launches.
>This vehicle had the stage mentioned before, whether a six engine centaur or
>whatever, and the Command and service module as the payload to to a suborbital
>trajectory. This combination was unable to boost the 45,000 lbs CSM to orbit.

Uh, no. The original Saturn C config was three stage, using Von Braun's Saturn
booster as the first stage. The second stage (S-IV) was to have had 4 LR-119
(may have that number wrong, it was to be a growth version of the RL-10, aka
LR-115) engines. The third stage (S-V) was to have been powered by 2 RL-10
engines. The S-V was NOT Centaur. They both were designed around a pair of
RL-10s, but had very different avionics and structure.

The S-IV evolved to use 6 RL-10s, thus avoiding the cost of developing a new
engine.

The 'C' designation was dropped somewhere along the way, with the Saturn C-1
becoming simply Saturn 1. FWIW, the Saturn A and B proposals used conventional
propellants in their second stages, and both had a third stage similar to the
S-V.

The first Saturn 1s flew with dummy second and third stages, and no fins. The
first block 2 Saturn 1 flew with a live S-IV stage and a dummy S-V (and tail
fins). Subsequent block 2 Saturns had dummy Apollo CSMs instead of the dummy
S-V.

The original intent was to fly the two stage Saturn 1 for LEO and the three
stage variant for lunar/planetary missions (unmanned of course). Remember that
the Saturn program predates Apollo. It was originally intended to produce a
family of general purpose ELVs.

>Finally there is the famous Saturn 1B that carried the manned Apollo CSM/LM to
>orbit. This configuration also carried the Saturn V, SIVB stage, which is the
>third stage of full up Saturn V. This combination was able to boost the
>full Saturn V payload to LEO altitude of 105 nautical miles.

The Saturn 1B, aka Uprated Saturn 1, was developed to meet the increasing mass
of the CSM. As you said, the CSM grew beyond the original Saturn 1 LEO
capability. The Saturn 1B could lift the CSM or the LM, but not both (i.e. it
could not carry the full Saturn V payload to LEO).

>This is the booster
>that was used for the Apollo 7 mission. I forget whether it was used for
>Apollo 9 or whether that was a full up Saturn V.

The only manned Saturn 1B flights were Apollo 7, Skylab 2,3,4 and ASTP.

gary

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

Date: 23 Dec 92 19:42:05 GMT
From: Dillon Pyron <[e-mail]>
Subject: Aurora chase planes (was Re: Aurora)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (David Smith) writes:
>
>I think people are getting a little too hung up on the "chase" word.
>If I recall right, what started this was that an observer said he
>saw this unidentified plane being chased by an F-15 or F-16.  As
>an observer, how can you tell if one plane is "chasing" another or
>accompanying it?  (Mary's definition of "chase plane" is the standard
>one for testing aircraft but we're really talking about an "accompanying
>plane")  Unless there was some major manuevering going on you can't say
>that the F-15 was "chasing" or attempting to intercept with the intent
>of shooting it down or identifying an unknown plane rather than accompanying
>it as a "chase plane".

If I saw one aircraft, armed or not, I would feel safe to assume it to be a
"companion" plane.  If I saw two, armed to the teeth, one behind and slightly
below, the other off center, above and further behind ... The Air Force guys I
grew up with call that "snakes and pistols".  ie Sidewinders and guns.

If you were to see only one "chase" aircraft, it is probably just that.  Most
air forces (includes USN) prefer to fly in wing pairs.

Not that I speak with any real athority.  Mary, does this seem like a plausible
explanation (although not complete).
--
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)     |"Pacts with the devil are not legally
[e-mail]          |binding!"
PADI DM-54909                     |-Friar Tuck   _Robin Hood:The Hooded Man_

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

Date: Wed, 23 Dec 1992 00:14:34 +0000
From: Anthony Frost <[e-mail]>
Subject: Breeder reactors
Newsgroups: sci.space


  >> cost? (For that matter, how much does U235-depleted uranium
  >> cost?)

  > I'd think it should be free to anyone wanting to haul it
  > away (though the governement probably doesn't treat it that
  > way).

I believe a fair quantity of it gets used in munitions. A depleted uranium
slug coming out of some form of gun goes through armour plating quite
nicely. Apparently, along with the bits that go bang, kids in Kuwait are
encouraged not to pick up any they see round the desert due to slight
residual radioactivity!

          Anthony

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

Date: Wed, 23 Dec 1992 23:06:47 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: fast-track failures
Newsgroups: sci.space

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

>Today's overhead is horrible, but $100,000 1940s dollars is only about
>$2 million 1992 dollarettes.... That's about 20 engineers in a Motel 6
>for six months, no machine shops, hangers, mechanics, flight test equipment,
>nada.

You think a typical engineer earns $100,000 a year?

I want to work for your company!

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

Date: 23 Dec 92 23:08:45 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: fast-track failures
Newsgroups: sci.space

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

>Of course the SR-71 was a black program funded by clandestine government
>agencies to the tune of we don't know how many billions of dollars.

Well, we do know that Kelly Johnson had no more than 100 engineers
working on the project.

How many billions can 100 engineers manage to spend in just 18 months?

Probably not enough to pay for the toilet paper in men's room
used the accountants that would have been required to run the
project your way.


>All technical development programs are subject to failure. You only
>have to look at the number of discarded prototype designs in any
>industry to see that.

Except, as Henry has shown, there don't seem to be nearly as many
"discarded prototype designs" as you believe. (By roughly a factor
of 10. :-)

>Any management program that doesn't plan for
>the failure of certain subsystem developments to come in on spec,
>on time, and on budget, is going to have programs that fail more
>frequently than those that do plan for such contingencies.

There's a difference between planning for contingencies and
basing your entire project plan on the assumption that, no
matter what, you ultimately will fail.

>Now that's not to say that *any* program can't be mismanaged, they certainly can.

Name one program run your way that was *not* mismanaged.

>With major development programs today costing as much as they do,

To pay for bean-counters, redundant paperwork, and CYA

>using a management style that doesn't plan for contingencies

Bullshit.  *Every* government program for the last 20 or so years
has followed your failure-oriented approach.  *Including* the
Space Shuttle program, the ridiculous Rogers Commission
report notwithstanding.  Government programs thrive on
failure because of the Federal teat.  As long as they
do not meet their goals, funding continues.  Lifetime
job security.  Success-oriented programs pose the risk
that (shudder) goals will be met, the project will be
over, and those involved will have to find work somewhere
else.

Like most government reformers, you refuse to recognize that
the conditions you decry are the *results* of your reforms.
You simply ascribe the worsening conditions to the fact that
your reforms have not been implemented thoroughly enough.


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

Date: Wed, 23 Dec 1992 20:25:46 GMT
From: Henry Spencer <[e-mail]>
Subject: funding for Lunar Prospector urgently needed
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Again, the Lunar Resources Data Purchase Act will provide a solid funding base
>for a resumption of lunar science flights.

If it passes.

>Congress didn't fund NASA's lunar
>orbiters, because of the fear that a new start for SEI hardware would be an
>implicit new start for a manned return to the Moon ...
>... This new approach alleviates that concern...

How?   I don't think the details of how the data is obtained are going to
make much difference.  It's money for an important SEI precursor mission,
no matter how you slice it.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Wed, 23 Dec 1992 19:47:09 GMT
From: Richard Wagener <[e-mail]>
Subject: Giotto Sample Return ?
Newsgroups: sci.astro,sci.space

From Eos 73, 1992 August 18 p. 347:

... Its [Giotto's] orbit brings it to within 210000 km of Earth on
July 1, 1999.  Although the spacecraft still has some fuel left, ESA
has no plans for more Giotto missions. - Stephen Cole

My question(s):

Is there enough fuel to change the orbit for a closer encounter
with Earth?  Could it be aerobrake'd into a stable orbit from which it
could be captured and returned by the shuttle?
Would the returned probe contain scientifically useful cometary
samples?

I would think that an aerobrake attempt should be made if it's
possible, the worst that could happen is an early fireworks display
for independence day (U.S.) ;-)
--
[nosave]
Tschuess ...rick...
_______________________________________________________________________________
Richard Wagener                |

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

Date: 23 Dec 92 23:43:31 GMT
From: Henry Spencer <[e-mail]>
Subject: ground vs. flight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Greg Moore) writes:
>>"Someday" was 1966, on Gemini 10.  And the target craft for the EVA wasn't
>>even stabilized -- it was an old Agena, batteries long since dead...
>>
>    I wasn't aware of this.  What did Michael Collins do while on
>the Agena?

Apart from just generally evaluating how easy it was to do -- not very --
he retrieved a micrometeorite experiment package that had been put on
the Agena in hopes that it could be returned to Earth eventually.

>    ... what is
>the maximum mass that the RMS can handle?

I think it's rated for the theoretical maximum shuttle payload, 65klbs.
It's not rated for the full mass of an orbiter, which is why the station
arm will eventually take over the capture-for-docking job.

>    BTW, what has the success rate been with the RMS on grabbing
>stuff with a handle?  Anyone have any clue? 80% 90%?  Let's
>not even consider the stuff it's had to attempt to grab that didn
>have handles...

The arm really *can't* grab anything that doesn't have a proper grapple
fixture on it, because the "hand" isn't a general-purpose gripper -- it's
designed solely and only to grab grapple fixtures, and is very specialized
for exactly that job.

As far as I know, the success rate for grapple fixtures is 100%.  They've
sometimes had to proceed slowly and carefully, but I don't think they've
ever had to abandon a grabbing attempt.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Wed, 23 Dec 1992 20:27:45 GMT
From: Henry Spencer <[e-mail]>
Subject: LEI financing
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Congress. This organization did pass the Launch Services Purchase Act...

And did deny Griffin any significant Moon/Mars funding at all.  The problem
is the word "Moon", not the word "purchase".
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Wed, 23 Dec 1992 19:32:34 GMT
From: Gary Hughes - VMS Development <[e-mail]>
Subject: MOL (was Re: Terminal Velocity of DCX? (was Re: Shuttle ...))
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Tom A Baker) writes...
>The very first MOL flight (and only one, if I recall correctly)
>was basically a test of the Titan III, on its way to being man-rated.
>(Does anyone remember if the strap-ons were solids?)  The MOL was a
>mock-up, just a cylinder the right size and shape.  The Gemini capsule
>was a donation to the Air Force from NASA, the former "Gemini 2"
>capsule that had flown unmanned.

Apart from the Gemini B capsule and the dummy MOL, it was an otherwise standard
Titan 3C (which was designed for man rating, btw). The dummy MOL served as a
payload shroud for a group of satellites that were deployed after the Gemini
had been sent on it's reentry course.

gary

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

Date: 24 Dec 92 00:28:26 GMT
From: Hugh Emberson <[e-mail]>
Subject: MOL (was Re: Terminal Velocity of DCX? (was Re: Shuttle ...))
Newsgroups: sci.space

>>>>> On Wed, 23 Dec 1992 04:02:29 GMT, [e-mail] (Tom A Baker) said:

Tom> The very first MOL flight (and only one, if I recall correctly)
Tom> was basically a test of the Titan III, on its way to being man-rated.
Tom> (Does anyone remember if the strap-ons were solids?)  The MOL was a
Tom> mock-up, just a cylinder the right size and shape.  The Gemini capsule
Tom> was a donation to the Air Force from NASA, the former "Gemini 2"
Tom> capsule that had flown unmanned.

It was an MOL sized tube (a fuel tank from something I think) and a
modified Gemini capsule with a hatch cut into the heatshield.

Tom> I think it all orbited for a few days before burning on reentry.  Yes,
Tom> it was certainly unmanned.

It was on a sub-orbital trajectory.  The test was to see how the Titan
would handle such a long payload and to see if the heatshield on the
Gemini would work.


Merry Xmas






--
Hugh Emberson -- CS Postgrad
[e-mail]

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

Date: 23 Dec 92 22:49:05 GMT
From: Dave Michelson <[e-mail]>
Subject: MOL (was Re: Terminal Velocity of DCX? (was Re: Shuttle ...))
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Hartmut Frommert) writes:
>[e-mail] (Edward V. Wright) writes:
>
>>You heard wrong.  One MOL flew (unmanned).
>
>Could somebody provide data ?

The only MOL related flight of which I am aware flew on November 3, 1966.
Here are a few more details for the curious...

A Titan III-C carried a "simulated" MOL (an old fuel tank) with a "used"
Gemini capsule on top.  The whole payload stack was 49 feet long.

The unmanned Gemini capsule had previously flown (but I'm not sure which flight
- GT-2?) and had had a 24-inch circular hatch installed in its heatshield.
It was separated from the simulated MOL at an altitude of 127 miles, splashed
down 5500 miles downrange, and was recovered by the USS LaSalle.  The modified
heatshield performed satisfactorily during re-entry.  The heatshield test was an
important milestone in the MOL program.

Meanwhile, the transtage was ignited twice, the empty fuel tank was placed
in a 185-mile orbit, and three military research satellites were ejected.
The mission of the first was classified.  The other pair were used to study
propagation through the ionosphere between satellites in orbit (as opposed
to earth-space propagation effects.)

---
Dave Michelson
[e-mail]

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

Date: 23 Dec 92 23:28:38 GMT
From: Henry Spencer <[e-mail]>
Subject: MOL (was Re: Terminal Velocity of DCX? (was Re: Shuttle ...))
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Pat) writes:
>...he  said that something called "Apollo
>Telescope Mount"  was the SOn of MOL...
>... I am wondering if he was referring
>to the astronomical section of SKYLAB?

The ATM was the Skylab solar-telescope assembly.

>... he implied that it had been
>transmorged,  but that it still had a lot of MOL-like systems and fixtures.

I find this extremely difficult to believe.  For one thing, there was *no
resemblance* between the two projects.  MOL was a pressurized manned lab,
sort of a mini-Skylab.  The ATM was an unpressurized unmanned telescope
platform which happened to be attached to Skylab.  (It had originally
been planned to be attached to a modified Lunar Module ascent stage,
which would have been its crew station, and there was some thought to
building it into a modified LM descent stage... but both of those ideas
were discarded in the end.  The ATM's crew station was in the Skylab
docking-adapter section.)

Skylab did use some bits and pieces developed for MOL, e.g. the toilet,
but as far as I know there was no major subassembly transferred intact
from the one project to the other.  There is no mention of such a
relationship in the Skylab News Reference or in Living And Working In
Space (NASA SP-4208, the NASA History book on Skylab).
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Wed, 23 Dec 1992 20:35:51 GMT
From: Henry Spencer <[e-mail]>
Subject: satellite costs etc.
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>... A ten year life zero defects
>GEO comsat like K2 is much cheaper than a 1 year life package
>that costs 20 times less. That's because most of the investment is
>not in the satellite, it's in the Earth based terminals that use it.

I don't grasp this argument.  It's the same Earth-based terminals either way.
If you're providing a service, you plan to do so over more than one satellite
lifetime, either way.  Twenty years of service is cheaper with mass-produced
short-life satellites, even with your (fairly unfavorable) assumptions.

>... Since the satellite represents a single point failure node...

This is your assumption, not a self-evident fact.  Communications networks
normally have redundancy to cover predictable single-point failures.
Even today's gold-plated satellite networks do, despite the expense.

>... and since for most orbits
>the satellites aren't retrievable or repairable, and DC won't change
>that...

Again, your assumption, not a self-evident fact.  Cheap launches change
almost everything, including the feasibility of retrieval and repair.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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Newsgroups: sci.space

From: "Edward V. Wright" <[e-mail]>
Subject: Re: numerous/ 1:ASAT 2:Water 3:misquotes
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In <[e-mail]> [e-mail] (Daniel Burstein) writes:

>  While very few nations have the capability to destroy orbiting
>satellites, countries have another option.  It is relatively
>trivial  to "blind" or otherwise disable
>an overhead platform.  In simplified terms, just take a few
>megawatts of power, hook it up to a radar unit, slide through
>a few frequencies, and there go the satellite systems.

This is another "idiot" argument.  You assume that people who
spend their lives designing and building satellites for the
Defense Department aren't as smart enough to realize that
satellites are vulnerable to electronic interference and take
steps to harden them against it.  I can assure you, they are.
No, don't bother asking for details.  I don't know and couldn't
tell you if I did.


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End of Space Digest Volume 15 : Issue 591
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