Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO593.TXT

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Date: Thu, 24 Dec 92 05:29:43
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #593
To: Space Digest Readers
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Space Digest                Thu, 24 Dec 92       Volume 15 : Issue 593

Today's Topics:
                                 "DC"
                       Asteroids, minor planets
                 Aurora chase planes (was Re: Aurora)
                      DC vs Shuttle capabilities
        I thinI see our problem. (Was Re: Terminal Velocity of
                              Lunar ice
        Stupid Shut Cost arguements (was Re: Terminal Velocity

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Date: Thu, 24 Dec 92 00:17:20 EST
From: John Roberts <[e-mail]>
Subject: "DC"

-From: [e-mail] (Edward V. Wright)
-Subject: Re: I thinI see our problem. (Was Re: Terminal Velocity of DCX?
-Date: 23 Dec 92 16:58:35 GMT
-Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA

-In <![e-mail]> [e-mail] (Greg Moore) writes:
->    In reality it sounds more like you are talking about DC-10,
->DC-12, etc.
->    Unless you are saying that a 747 is the same plane as a DC-3
->was.
->    If your claims are about 50 years from now, or even 20
->eyars from now, I'll buy them.

-Do you have any idea how many DC-3s are still flying?  After 50
-years?

This "wraparound" of the DC designation is getting confusing! :-)

John Roberts
[e-mail]

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

Date: Wed, 23 Dec 92 23:58:34 EST
From: John Roberts <[e-mail]>
Subject: Asteroids, minor planets

-From: [e-mail] (bill nelson)
-Subject: Re: asteroids beyond Jupiter
-Date: 23 Dec 92 20:35:36 GMT
-Organization: Hewlett-Packard Company, Corvallis, Oregon USA

[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.

"Of the many thousands of minor planets, the vast majority appear
telescopically like stars - that is, as small points of light. The term
*asteroid* (meaning "starlike") is therefore often applied to these tiny
worlds. Another synonym is *planetoid*. The term *minor planet*, preferred
by the International Astronomical Union, is used in this text."

 from "Exploration of the Universe", by George O. Abell, C. 1964, 1969, 1975.

Actually, I prefer the term *asteroid*. You're welcome to set your own
definition, then point out that the only things that fit your definition
are the things that fit your definition, but I don't know how useful
such a statement is. :-)

There is evidence that some of the things we call asteroids used to be
comets.

John Roberts
[e-mail]

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

Date: 24 Dec 92 05:47:02 GMT
From: Mary Shafer <[e-mail]>
Subject: Aurora chase planes (was Re: Aurora)
Newsgroups: sci.space

On 23 Dec 1992 04:32:38 GMT, [e-mail] (Pat) said:

Pat> In article <[e-mail]> [e-mail] (David Smith) writes:
>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".


Pat> Mary, it didn't leap out at me from your post,  but I believe most chase planes
Pat> are loaded with a couple of cameras,  in the gun mounts and in the
Pat> cockpit, to try and record at or above  24 frames/second the behavior
Pat> of the experimental plane.  it is useful to know that a trim tab
Pat> tore off,  a minute before the test plane crashed.

No, we don't do this at all.  The only cameras that we ever carry _in_
the chase planes are in the hands of a photographer in the back seat.
AFFTC (Air Force Flight Test Center, which is what everyone means by
Edwards AFB) doesn't mount cameras on the hardpoints either.

All the air-to-air photography from Dryden, with the sole exception of
some footage from the NB-52B during drops, comes from handheld video
or cameras.

Pat> I think fighters are preferred in this mode,  because with all the hard points
Pat> you have lots of places to stick cameras or sensors.

As I said, we never mount cameras on the outside of the chase plane.
We do mount various cameras on the research planes.  For example,
the HARV has a 35-mm still camera in a faired box on one wing tip
and video cameras, downlinked to the ground, on the other wing tip,
on the vertical stabs, on the turtleback, and on the glareshield.
These are all sufficiently faired that they will not affect the
aerodynamics of the vehicle.

We also have no instrumentation in the chase planes.  We instrument
the research airplane extensively and we would certainly know what
happened to the plane in any incident based on that instrumentation.

--
Mary Shafer  DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA
[e-mail]                    Of course I don't speak for NASA
 "A MiG at your six is better than no MiG at all."  Unknown US fighter pilot

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

Date: 24 Dec 92 04:18:15 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: DC vs Shuttle capabilities
Newsgroups: sci.space

>In <[e-mail]> [e-mail] (Craig Keithle
y
>) writes:
>
>>   What if we don't accept your points, don't want to follow you (blindly)
>>and and don't want you to redistribute the $$$ in a way we disagree with?
>
>We'll do the job anyway, so that a couple decades from now, while
>you watch the 6:15 to orbit, you can lie to your grandkids and say,
>"I knew it was a good idea all along."
>
>
>>        Lets see a straw man proposal that clearly indicates (using the
>>published Shuttle schedule for the next few years)...
>
>In other words, let's take NASA's word that it can follow a
>published schedule it has never been able to follow before.
>
>And while we're at it, let's pretend that all the safety problems
>uncovered before and after the Challenger crash have been solved.
>Let's pretend that there will never be another Shuttle, that Congress
>won't shut down the Shuttle program for at least another two years
>(and perhaps forever) when there *is* another Shuttle crash, and
>that the Shuttle orbiters will last longer than their 100-mission
>design life as NASA is now saying (although the engineers who work
>on them say 25-to-50 missions is more realistic).

     And just how well has Titan IV, Atlas II, or Ariane held
     to the schedule? All have had major headaches from time
     to time (with two being presently so afflicted).
     I have no illusions about the Shuttle's record, but I
     object to those who say these problems will not occur on
     DC-whatever, which happens frequently here.


>>   If the Shuttle "detractors" wish, produce a schedule that replaces every
>>Shuttle flight starting with the next one.  This would used purely as a
>>center for discussion, because it would have to ignore the political
>>realities with cancelling the shuttle *today*.
>
>And let's see you show how continuing the Shuttle program will lead
>to real space development.  When does your flight schedule allow
>for a *real* space station.  Not a trivial, insignificant nothing
>like SS Freedom, but a modest-sized station (say 50 people) initially,
>capable of growing to 500 or more over the following decade.  A return
>to the Moon and the establishment of a self-sustaining lunar colony.
>Manned missions to Mars, the asteroid belt, and beyond?  The construction
>of *big* orbital telescopes, which make Hubble look like a toy.  Large
>numbers of unmanned "sailing ships" to probe every part of the solar
>system.  A manned station in polar orbit for meteorological research.
>Space tourism.  Space manufacturing.  Solar power satellites.

  I sure hope DC-whatever will do this, but I think its a matter of
  decades away using any approach presently in the works. Maybe a
  Space DC-3 or 4, but not Shuttle or DC-1.

>A true space transportation system would make all these things possible.
>Since you demand that we show "a long term vision," you must believe
>the Shuttle can also.  Please tell us when these flights are planned.

  Again, no illusions about the Shuttle. It's the best we have right now.
  Whether DC-1 will probe to be THE Space Transportation System
  (where have I heard THAT before) is another matter. You seem to believe
  that we think Shuttle is the best thing since sliced bread. We, on
  the other hand believe the same of you and DC. In reality, we're saying
  "sounds like a good idea, but until you have something flying we'll
  stick with the Shuttle, thanks." I don't call that being closed-minded,
  I call that good horse-sense.

  -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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

Date: 24 Dec 92 04:19:33 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: I thinI see our problem. (Was Re: Terminal Velocity of
Newsgroups: sci.space

>In <![e-mail]> [e-mail] (Greg Moore) writes:
>
>>       In reality it sounds more like you are talking about DC-10,
>>DC-12, etc.
>>       Unless you are saying that a 747 is the same plane as a DC-3
>>was.
>>       If your claims are about 50 years from now, or even 20
>>eyars from now, I'll buy them.
>
>I think it would do you a world of good to go out to your local
>airport and look around.
>
>Do you have any idea how many DC-3s are still flying?  After 50
>years?

        How many Mercury or Vostok are still flying?

>And the 747, which you cite as an example of a modern airplane,
>is well over 20 years old!

        747-400 is essentially a new aircraft inside an airframe
        which has been around 20 years. 747-400 debuted in the
        mid-80s. Using this argument, why can we not add new
        engines, a new cockpit, and new materials to the Shuttle
        and keep it flying as the Shuttle-400? :-)

        -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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

Date: 24 Dec 92 05:44:18 GMT
From: Henry Spencer <[e-mail]>
Subject: Lunar ice
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Richard Schroeppel) writes:
>I notice the proposed LEI probe doesn't include imaging.
>(1) How do they know where the probe is looking when it's taking data?

The instruments are not particularly directional, as I understand it.
The mapping from data to lunar surface is established mostly by the
location of the probe at the time.  Once the thing's primary mission
is complete, one strong possibility for an extended mission is to take
it to very low altitudes over particularly interesting areas, to improve
mapping resolution there.

Imaging is nice, but it takes a lot of downlink bandwidth and it's
awkward to do from a spin-stabilized probe (which is simpler and lighter
than a three-axis-stabilized one).  There's also not a lot of point to
it unless you can do it well, given that we already have so-so images
of most of the Moon.  Better imaging, especially multispectral imaging,
would certainly be useful, but it's a different mission.

>(2) Since "permanent solar shadow" != "permanent Earth shadow",
>    how about looking for ice glints by Earthlight?

The poles don't get much Earthlight either (possibly none at all in a
nice shadowy polar crater, although I'm not sure of the numbers).  There
is also some reason to suspect that persistent polar ice might well be
buried slightly.

The only way to settle the issue once and for all -- short of surface
exploration, that is -- would be radar imaging, I would think.  Alas,
that means a big spacecraft, for large antennas and plenty of power.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 24 Dec 92 04:18:56 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity
Newsgroups: sci.space

>>Right now, if you stopped all flights,
>>you could argue this cost (excluding interest) is about $150 million
>>a flight. (10 flights/orbiter, $1.5 Billion per orbiter).  This
>>number will shrink.
>
>That is by no means certain.  There's a good chance someone else
>will fly an orbiter into the ground in the next few years and the
>whole fleet will be grounded permanently.  And while the increasing
>number of flights tends to bring the average cost down, Shuttle
>improvement programs tend to push it back up again.

  Do you suppose that DC will not belly-up from time to time, too?
  The only space boosters which never failed were Saturn 1 and
  Saturn 5, and neither flew 25 missions. Who's to say that the
  firm which operates DC would not be ruined by an ill-timed DC
  wreck? Grounding Shuttle would be a political decision. Grounding

  DC would be a financial decision. The end result is the same.

  If the development costs are as high as you claim, the costs of
  such Shuttle upgrades as the new turbopumps and the glass cockpit
  are marginal. Even the ASRM is a drop in the bucket next to those
  numbers... Seems you're using two different figures here, a low figure
  which makes the upgrades a major increase in the costs and a high
  figure which makes Shuttle an impossible-to-recoup investment.
  Which is correct?

  -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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End of Space Digest Volume 15 : Issue 593
------------------------------