Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_4/V15NO499.TXT

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Date: Fri,  4 Dec 92 09:45:52
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #499
To: Space Digest Readers
Precedence: bulk


Space Digest                Fri,  4 Dec 92       Volume 15 : Issue 499

Today's Topics:
                      Comparative Launcher Costs
               Complexity (was Re: Shuttle replacement)
                             DC-X status?
                             DC-X Testing
                     DCX Transportation on Earth
    HST black hole pix *or* Hubble Hype? (Was: HST black hole pix)
NASA has 5 hand grenades still on the moon from Apollo missions (2 msgs)
                         NSSDC Data on CD-ROM
                       Pioneer plaques (2 msgs)
                     Shuttle replacement (6 msgs)
                      Space Calendar - 11/28/92
                      Space probe to pass Earth
             Voyager's "message"... What did it *say*?!?

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: Thu, 3 Dec 92 14:55:02 EET
From: @fuug.fi:[e-mail] (F.Baube x554)
Subject: Comparative Launcher Costs

From: Gary Coffman <ke4zv!gary> writes:
> Subject: Satellites more expensive on STS? (was Re: Shuttle replacement)
> At $20,000 a pound for Pegasus compared to $8500 a pound for Shuttle,
> Pegasus is the most expensive launcher, not the cheapest.

This can't be a valid comparison, can it ?

For one thing, right now aren't there more Shuttles than Pegasi ?

For another, isn't it a near-tautology that you can save money
by using a reusable low(er)-complexity airplane to get over
most of the atmosphere and gravity well ?

/fred :: [e-mail]

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

Date: 3 Dec 92 01:45:37
From: Craig Powderkeg DeForest <[e-mail]>
Subject: Complexity (was Re: Shuttle replacement)
Newsgroups: sci.space

In article <foo> [e-mail] (Brian Stuart Thorn) writes:
      The Space Shuttle flew 4 times and was declared 'operational'. That
      was a mistake, and no airliner has every seen anything like it.
      But the Space Shuttle is *not* an airliner. (It makes the Concorde
      look like a VW Bug... or a bicycle :-)

Keep careful watch on those vehicle complexity figures -- counting
each sliding hunk o' metal separately, the bicycle has more moving
parts in its power train than does the VW!


--
DON'T DRINK SOAP! DILUTE DILUTE! OK!

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

Date: Thu, 3 Dec 1992 00:42:54 GMT
From: Rich Kolker <[e-mail]>
Subject: DC-X status?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Matthew Kaiser) writes:
>>what's the status on the DC-X and Y?
>
>DC-X:  under construction for flight in spring.
>
>DC-Y:  proposed but unfunded.

And on schedule.

In one of those serindipitous occurances, the husband of a long time friend
is one of the piklots (oops pilots), yes pilots...plans are to pilot the
DC-X from the ground, just as will be possible with the DC-Y when they
want to fly it unmanned.  They're moving from Edwards to Albequerque
shortly for the test program.  I didn't get an exact date, but I'll be seeing
them over Christmas.  The move is scheduled for February, TJ told me flight
test should begin in late March/early April.

++rich
-------------------------------------------------------------------
   rich kolker       [e-mail]
                          It's been a long, long time
--------------------------------------------------------------------

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

Date: Thu, 3 Dec 1992 01:45:53 GMT
From: Carl Hage <[e-mail]>
Subject: DC-X Testing
Newsgroups: sci.space

Well you have me convinced that the DC-X -> DC-Y -> DC-1 development
program is a worthwhile project. Although I have seen critisms that
DC-X won't go into space and won't prove anything for DC-1, I particularly
like the idea of building a subscale prototype, experimenting with it and
then asking for more money. I think congress and the public would agree
with me on this.  More government projects should be done like that. I
think that if DC-X works, congressional oversight will be in favor with
SSTO and DC-Y will be funded with higher priority than other competing
projects.

On the other hand if DC-X crashes, it looks like the program would be
cancelled, partly because it is outside NASA. I have seen videos of lots
of other hovering type vehicles, and they almost always crash during
testing. I assume the project members understand the implications from a
crash on the first flight, and they are doing everything possible to be
safe. This brings up some questions in my mind about what kind of testing
is planned prior to flight.

Presumably, individual systems can be tested independently. Is it
practical to build a test/launch platform with the completed DC-X vehicle
held to the ground while the engines are run and all the control systems
are exercised? What kind of simulations are being done for testing and
pilot training, etc.?

This brings up another question. Does back wash from the engines present a
problem on takeoff or landing? Does the launch pad need to deflect the
exaust away from the vehicle to prevent damage and/or is shielding needed
to prevent damage?

For DC-X, can a large parachute be placed on the top so if something went
wrong it could be recovered safely without power?

In a prior article Allen explains that the payload and crew area of DC-1 is
above the LH2 tank and below the LOX tank. Interesting. I assume the reason
is to keep the center of gravity forward, or is there something else?
(I guess a cone shaped tank might be better than a cone shaped payload
bay.) That would seem to present some structural challenges. Is there
supposed to be a large (2 quarter circles) door to load and deploy the
payload? Would the launch pad need some special jig to hold up the top of
the ship while the doors were open on the ground?


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

Date: 3 Dec 92 08:28:54 GMT
From: James Thomas Green <[e-mail]>
Subject: DCX Transportation on Earth
Newsgroups: sci.space

I suppose this would apply more to the DCY/1/...

Once the vehicle was on the ground, how would it be transported from
the landing site (say Edwards AFB) to the launch site (say Florida)?

As I type the question, I realize that the DC... could be partially
fueled for a suborbital jump, but if that's not the case, is there any
vehicle (like the 747 used for the shuttle) to transport the DC... in
mind?


                                                                  A/~~\A
                                                                 ((O  O))___
                                                                   \  /     ~~~
  #                       #                         #              (--)\    #
--#---x---x---x---x---x---#---x---x----x----x---x---#---x---x---x---x---x---#---
  #    James T. Green     # [e-mail] #                    \  #
--#---x---x---x---x---x---#---x---x----x----x---x---#---x---x---x---x---x---#---
 \#//  \|/    \\\|||//   \#/   \\\||/   \||///    \\#|//     \\\\\|||/// \|/#\|
                              O u t s t a n d i n g   i n   t h e   f i e l d !

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

Date: Thu, 3 Dec 1992 03:38:39 GMT
From: Gerald Cecil <[e-mail]>
Subject: HST black hole pix *or* Hubble Hype? (Was: HST black hole pix)
Newsgroups: sci.space,sci.astro

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>,
>[e-mail] (Gerald Cecil) writes:
>> Hey people, stop listening to the Hubble Hype for a moment and *look* at
>> the image!  You will *not* see an accretion disk.  You *will* see a bright
>> ring that ends 170 parsecs (= 1 arcsec for a more reasonable distance of
>> 35.1 Mpc [Nearby Galaxies Catalog, Tully]) from a bright smudge in the
>> center.
>[remainder of good explanation deleted.]
>
>I'd like to make it quite clear that I wasn't propogating any "Hubble Hype"
>and that I consider the insinuation to have been impolite.  I work in the
>HST Operations division, and I'm as aware as anyone around here of the
>instruments' limitations.
>
>What I said, and what I'll reiterate, is that the image had not been processed
>using any unusual "computer enhancement" techniques as a previous poster had
>suggested.  Interpretation of the image is left to the user.  It is, as I've
>said before, public domain.  If anybody wants to dispute the claim that it
>"represents a cold outer region which extends inward to an ultra hot accretion
>disk within a few hundred million miles of the suspected black hole" then
>please address those questions to Walter Jaffe and Holland Ford.  It's their
>data and their interperetation.
>-Bill Gawne,  Space Telescope Science Institute

I'm sorry, my reference to ``Hubble Hype'' was not directed at your comments
on the data processing, but to the more breathless excesses of the NASA
press release that accompanied the pretty picture.  This generated several
statements (in these news groups among other places) that ``the Hubble image
shows an accretion disk around a black hole.''  Nope.  I wished only to
reinforce the more cautious sentence in the release that you quote.  Accretion
disks per se are too compact for Hubble to resolve in external galaxies.  In
any case, it's a nice image and one more small step to understanding active
galaxies.
--
Gerald Cecil [e-mail]  919-962-7169
Physics & Astronomy, U of North Carolina, Chapel Hill, NC 27599-3255 USA

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

Date: 3 Dec 92 00:07:01 GMT
From: Gary Coffman <ke4zv!gary>
Subject: NASA has 5 hand grenades still on the moon from Apollo missions
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>
>Ordinary firearms wouldn't work in a vacuum anyhow.
>The gunpowder couldn't burn. The same might be true at high
>altitudes on the Earth's surface, as I've heard that in a
>particular South American city (I think it was La Paz, Bolivia),
>there's not enough oxygen in the air for them to really require
>a fire department.

Oh please. The KNO3 in black powder is the oxidizer. Smokeless
powders use nitrocellulose, nitroglycerin, or both (called double
base). They dissociate exothermally without external oxygen. If you
examine a cartridge, even casually, you'll note that there is no
opening for oxygen to enter. In fact, most firearms work underwater
if they have a sufficiently strong firing pin spring. Glock will
supply such a spring on request.

Gary

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

Date: 2 Dec 92 19:10:47 GMT
From: Bruce Watson <[e-mail]>
Subject: NASA has 5 hand grenades still on the moon from Apollo missions
Newsgroups: sci.space

In article <[e-mail]| [e-mail] writes:
|
|Ordinary firearms wouldn't work in a vacuum anyhow.
|The gunpowder couldn't burn. The same might be true at high

And rockets don't work in space because there is no air to push against.!-)

|altitudes on the Earth's surface, as I've heard that in a
|particular South American city (I think it was La Paz, Bolivia),
|there's not enough oxygen in the air for them to really require
|a fire department.
|
...and all the residents die of lack of oxygen. You've got to add
smileys. Some of us don't have the sense of humor you have.

--
Bruce Watson (wats@scicom) Bulletin 629-49 Item 6700 Extract 75,131

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

Date: Thu, 3 Dec 1992 13:26:48 GMT
From: Ron Baalke <[e-mail]>
Subject: NSSDC Data on CD-ROM
Newsgroups: sci.space,alt.sci.planetary,alt.cd-rom

In article <[e-mail]>, [e-mail] (Robert J. Kinder) writes...
>I'm thinking of buying the NASA CD-ROM's for the "Voyager Spacecraft to
>the Outer Planets from the Planetary data System (PDS)" from the National
>Space Science Data Center.
>
>The description of this says "Compressed and browsed images accessed
>through the IMage DISplay (IMDISP) retrieval program.".

The Voyager images are 800x800 pixel resolution.  The budget to do the
Voyager CD-ROMs allocated 12 CD-ROMs, so the images were compressed so
that they would all fit.
Software to uncompress the images is on the CD-ROMs.  The images are about
670K when uncompressed.

The browse images are smaller versions of the images.  They are 200x200
pixel resolution or 1/16 the size of the original.  These images are
not compressed and can be viewed directly off the CD-ROMs.  All of the
browse images for a particular planet are on single CD-ROM.

>CD-ROMs are available for Uranus (6538 images), Saturn (4000) images,
>Jupiter (6000 images), and Neptune (10,000 images).
>
>Has anyone looked at these images?  Are the pictures very detailed and
>diverse?

Yes.  Keep in mind the images are the raw unprocessed data from Voyager.
The images are black and white.

>Or do you just see 4000 pictures of Saturn a little closer each
>time?

Also, yes.  The images are stored by spacecraft clock time, and in the
order that Voyager took them.  If you viewed them in the order, you will
see the planet as a small dot, and it gradually gets bigger and bigger.
Then suddenly the planet gets so big, and the entire planet no longer
fits in a single image.  Then the spacecraft is past the planet, and
looking at it backlit against the sun, and starts to shrink.

If you want to get a feel for this, then use the BROWSE command from the
IMDISP program.  First, insert the CD-ROM that has the browse images,
go to to browse directory where all of the browse images are.  Then cd
into one of the planets or moon directory and type:

BRO SIZE 200 ALL

This will display all of the browse images on the screen.  But I warn
you, this may run for a couple of hours if you select Jupiter or Saturn.

Alternately, typing:

BRO SIZE 100 SUB 2 ALL PAUSE NOLABEL

will display the images at 100x100 resolution without the labels, and will
pause when the screen gets full, continuing when the enter key is hit.

>Which is the most interesting data set to buy first?

Since you can get all 12 of the Voyager CD-ROMs for only $86, I'd suggest
that you get the whole set.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The 3 things that children
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | find the most fascinating:
|_____|/  |_|/       |_____|/                     | space, dinosaurs and ghosts.

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

Date: Thu, 3 Dec 92 08:31:32 EST
From: John Roberts <[e-mail]>
Subject: Pioneer plaques

-From: [e-mail] (Bill Higgins-- Beam Jockey)
-Subject: Re: Voyager's "message"... What did it *say*?!?
-Date: 3 Dec 92 00:13:03 GMT

-Carl Sagan describes the Pioneer plaques, and humanity's reaction to
-them, in one of his books.  I think it's *The Cosmic Connection.*  The
-picture on the plaque was drawn by Linda Sagan, his wife at the
-time.

Lageos also contains a plaque, specified by Carl Sagan, but this time made
of stainless steel, I think. The justification is that the Lageos satellites

I wonder if anyone's proposed putting a plaque on Dante. :-)

John Roberts
[e-mail]

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

Date: Thu, 3 Dec 92 08:34:02 EST
From: John Roberts <[e-mail]>
Subject: Pioneer plaques

Correction of previous post:

Lageos also contains a plaque, specified by Carl Sagan, but this time made
of stainless steel, I think. The justification is that the Lageos satellites
are supposed to remain in orbit for more than eight million years.

John Roberts
[e-mail]

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

Date: 2 Dec 92 23:42:29 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>In article <[e-mail]> [e-mail] (Robert B. Whitehurst) writes:
>
>>    I'd be very surprised if the pad is "just" a support.  One of
>>the problems with the recent (test? use?) of an MX booster as a
>>commercial launcher was severe acoustic loading due to its launch from
>>an unimproved site.
>
>I think the fact that they use solids would also be a major factor.
>
>>I would expect a pad with exhaust diverters, water quenching, etc. to
>>reduce similar loads on a DC (or any big rocket for that matter).
>
>Nope. In fact, acoustic load is actually better than an airliner since
>it goes straight up and doesn't fly low over populated areas.

Acoustic loading is the mechanical force on the spacecraft caused by
sonic reflections from the ground during launch. As Robert says, this
is a serious issue with any large rocket. A spacecraft can be literally
hammered to pieces by this energy if the pad isn't designed to divert
or absorb it. The first 100 feet, and the last 100 feet in the case of
VTOL, are the most critical times for sonic hammering as well as a host
of other problems. A million pounds of thrust makes a big noise, orders
of magnitude higher than a little Harrier or other light VTOL. It's also
very hot. It will fry and spall concrete that isn't water cooled. Chunks
of flying concrete tend to make landing tricky. It's like landing on
a demolition charge.

Gary

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

Date: 3 Dec 92 00:27:48 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bruce Dunn) writes:
>
>        It would be very interesting for this general line of argument to
>compare the descent rate of a helicopter in the high rate part of an
>unpowered descent with the descent rate of an aerobraked DC-1.  Both vehicles
>are falling at a substantial terminal velocity, and have to do a well
>controlled maneuver to deaccelerate just before touchdown.  I suspect that
>the margins in terms of "hovering time" probably are a bit less tight on the
>DC-1.  Since this is apparently a routine maneuver in helicopter training,
>this would argue that the rocket powered analog might not be so hard as many
>people are making out.

The "high" sink rate required by an autorotating helicopter is about
700 feet per minute. That's a little fast, but F14s have hit carrier
decks with sink rates as high as 1200 fpm, though it blew a tire and
hurt the pilot's back. Normal carrier landings are at a sink rate of
500 fpm. There's enough energy stored in the main rotor of a helicopter
coming in on autorotation to abort a landing and lift back up 200 feet,
at least in a Hughes 500. It's a routine maneuver during pilot training,
but you'd prefer to avoid it in normal service. It makes the paying
customers nervous. It made me real nervous the first time.

I don't think a DC can aerobrake to a sink rate of 700 fpm. Probably
it can't aerobrake below 20,000 fpm, if that slow. It'd need *wings*
to get much slower than that. It has to come down on engine power, or
smear all over the landscape. Even a Harrier can dead stick to a runway
landing if it loses engine power in flight.

Gary

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

Date: Thu, 3 Dec 1992 01:45:46 GMT
From: Carl Hage <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

Lots of people write:
  - DC-1 is perfectly safe
  - DC-1 is dangerous
  - DC-1 will be a certified airliner
  - 747s crash into apartment buildings
  - etc.

This is ridiculous. Lets think about this realistically. First, I can't
see DC-1 being certified like an airliner since it isn't one, but so what?
It isn't meant to carry passengers or freight between cities. However,
DC-1 can have it's own classification from the FAA and launches can be
made regularly by commercial operators.

Everything that flies crashes: Cessnas, 747s, Space Shuttles, B1Bs, and
DC-1s. We all take risks. But there is no need to fly B1Bs or DC-1s over
populated areas, so when a B1B or DC-1 crashes it will be unlikely to
injure anyone but the crew. If DC-1 flies unmanned, then the crew won't
be lost when it crashes.

[e-mail] (Allen W. Sherzer) writes:
: DC-1 however, WILL be airliner certified and will fly from John Wayne
: Airport without destruct charges or blockhouses.

Come on, it doesn't make sense to fly DC-1 from John Wayne airport.
Airliners fly from John Wayne because they are taking passengers to Las
Vegas or whatever. DC-1 is taking freight or crew from Earth to space. It
is cheaper to ship the payload to the DC-1 launch complex rather than
build multiple launch complexes, or operate out of existing airports. You
can't get a non-stop flight from John Wayne to Antarctica, so why would
anyone expect to get a non-stop flight from John Wayne to orbit?

There would be no reason for DC-1 to have destruct charges since it
can just crash in the desert. Does Edwards AFB have blockhouses? I
suppose some shelters could be built in case of disaster, and there
would probably be a few minutes warning if a DC-1 launch or landing
was heading for the populated buildings.

From an ecomonic point of view I see no reason to have more than one
launch complex (at least on a continent). One complex could support all
the capacity required.  The maintenance and support from a central
facility would be much better than distributed facilities. A single large
LOX/LH2 manufacturing plant can be built, and fueling can be done at the
pad by transferring the fuel to the pads via rail car.

The location for the launch complex would be based on having a large
sparsly populated area, good weather conditions, and access to rail or
possibly barge shipping. Being away from the ocean probably improves
weather conditions. There's no need to be over water since a fishing
boat can be destroyed as easily as a ranch house. For now, White Sands
probably makes a lot of sense for DC-X and DC-Y. A permanent site probably
wouldn't want to be located on a classified military installation.

I suppose the military would want thier own launch complex, although
probably only for political reasons, not from economic or security reasons.
It would make more sense to have a small secured area within a large
commercial complex.

There would probably be multiple landing sites selected in case of bad
weather. These locations could have the equipment to safely remove the
remaining fuel, etc. and pad wheels to move the spacecraft to rail or
boat transport. It probably isn't economic to ship by air, e.g. refueling
with LOX/LH2 and flying to the main complex.

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

Date: 3 Dec 92 05:53:07 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

>Yes, the real crime was treating Shuttle as an operational system after
>so few flights. No commercial aircraft would be certified operational
>after so few takeoffs and landings. Shuttle is still significantly
>more risky than any operational aircraft, yet we fly it now. My point
>is that the incremental risk for flying it with some of the potential
>problems unfixed may not have been that much higher than the risks
>it endures now, after the fixes.

   The Space Shuttle flew 4 times and was declared 'operational'. That
   was a mistake, and no airliner has every seen anything like it.
   But the Space Shuttle is *not* an airliner. (It makes the Concorde
   look like a VW Bug... or a bicycle :-)
   The Space Shuttle, as its name implies, is a SPACE VEHICLE. Shuttle
   flew 4 times before being declared operational, and was really in a
   major test program through STS-9 in 1983. This looks conservative
   compared to the Saturn 5's history. Two test flights (one of which
   had severe problems) and the thing was manned and sent to the Moon.
   Operational on flight number three.

   -Brian


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

Date: Wed,  2 Dec 92 21:52:30 PST
From: Brian Stuart Thorn <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

>The space shuttle does too have a blackout zone.  The Zone of Exclusion is
>over the Indian Ocean, and the exact size depends on shuttle altitude.
>In addition, the shuttle can be out of radio touch due to attitude
>requirements that block the Ku Band antenna.  There is a blackout due to
>atmospheric ionization during reentry.  Finally, during the entry after
>that point, there have been certain high inclination flights that,
>due to the approach path, have been out of comm range during much
>of the run across the US into KSC.
>
>   rich kolker       [e-mail]

  The Zone of Exclusion is generally not referred to as a blackout
  zone, although it technically is. In any case, this discussion was
  referring to re-entry, which has not begun when the Orbiter passes
  through the ZoE. Having watched most of the Shuttle landings on
  NASA Select (particularly the KSC landings) I don't recall a case
  where NASA did not have contact with the Shuttle during overflight
  of the American continent.
  The old Apollo, early Shuttle blackout due to atmospheric ionization
  was overcome by sending the com signal upward to the TDRS satellite
  rather than trying to go downward through the ionization effect.
  The Discovery mission currently in progress is a high-inclination
  (57 deg) flight scheduled to land at Kennedy Space Center.
  We'll see.

   -Brian


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

Date: Wed,  2 Dec 92 21:51:54 PST
From: Brian Stuart Thorn <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space.shuttle,sci.space

>I checked this out a while back.  The Apollo 19 Saturn is at KSC, the Apollo
>20 Saturn is at JSC (I could check out the actual SV designations in Starges
>to Saturn, but you get the idea).  The Saturn V at MSFC is the Engineering
>test model, not a flight article.
>-------------------------------------------------------------------
>   rich kolker       [e-mail]

   Rich.. I suggest you look again.
   Granted, this isn't the most technically efficient way to judge but...

   There are four black vertical stripes rising up from the engine
   fairings on all S1C stages, the stripes are spaced 90 degrees apart.
   (One side of each fin is black, the other is white, this is the
   demarcation line for the vertical stripes.)
   To the best of my knowledge, only one Saturn 5 first stage was
   completed with a horizontal black stripe on the interface between the
   LOX tank and the Kerosene tank, about 1/3 the way up from the base of
   the stage. This horizontal stripe connected the four vertical stripes.
   The only S1C that had this stripe was Saturn-Apollo 500F (SA-500F)
   the Facilities Check-out Vehicle. The S1C that is part of the Saturn 5
   display at the Vehicle Assembly Building at Kennedy Space Center
   has this stripe.
   Further, I believe that the SA-500F was stacked and sent to the pad
   in 1966, and never left. Unless KSC has another Saturn 5 hiding about
   somewhere, this display must be 500F.
   Finally, I can't imagine that NASA paid to have the Apollo 19 booster
   shipped to KSC when they knew that it would never fly. I doubt even
   Apollo 18 would have made the barge-ride.

   -Brian


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

Date: 3 Dec 92 05:55:17 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Space Calendar - 11/28/92
Newsgroups: sci.space,sci.space.shuttle

>>     January 1993
>>     *25 - STS-54, Endeavour, TDRS-F
>     ^^^^^
>
>when did this change? i haven't heard anything about problems that would push
t
>he
>date back 12 days. anybody have any info/confirmation?
>
>btw, normally i wouldn't care that much; but, i'm trying to plan a vacation
>around seeing the launch. any info would be helpful. thanks.

 It hasn't changed. STS-54 is still 'targeted' for January 13. No
 indication of trouble. Endeavour is going out to the pad on Thursday,
 TDRS-F is already there. Wednesday's successful Discovery launch
 improves the odds of a January 13 launch. If it's cold, they might
 wait a day or two, though.

 I have no idea where the January 25 date came from.

 -Brian


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

Date: Thu, 3 Dec 1992 05:19:59 GMT
From: [e-mail]
Subject: Space probe to pass Earth
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Josh 'K' Hopkins) writes...
>[e-mail] writes:
>>Hmm.  Me just had crazy idea.  Aim the spacecraft so the air resistance
>>will attempt to force the stuck HGA open (like an umbrella or parachute)
>>while trying to crank it open at the same time.  Perhaps this will free
>>it?  Or tear it apart? (I'd guess not, as it was expected to be fully
>>open now)

>I always like to encourage free thinking and figuring things out for yourselves,
>but lets take that a little farther fellas.   190 miles is low, but not _that_
>low.  Sattelites can stay up there for a while.  In addition, we know that
>Galileo will be moving fast ('cuz that's the whole point of a planet swingby).
>We can therefore assume that Galileo will be down that low for a very short
>amount of time (I'm guessing tens of minutes below a given moderately low
>altitude).  Now if satellites (which aren't exactly standing still) can hang
>around for weeks or months at that altitude before worrying about drag, I think
>we can safely assume that air won't put major loads on Galileo.  I'd hope the
>calculations have been done, but I doubt they had very exciting results.

Well, I have to comment.  First I said it was a crazy idea, it was something
that came to me at the time I read the query.  Second, while I know the air
at 190 miles is quite thin, I thought that *maybe* two things *might*
counteract it - first, the thing is really moving - no wimpy orbital
velocities, the thing is moving with enough speed to escape Earth's gravity
at 190 miles high and continue to Jupiter.  Such speeds greatly amplify the
effect of what little air there is.  Second, oriented correctly, the
HGA would be aerodynamically awful - like a parachute, doing a good job
at catching those few molecules and converting them to a force.
Finally, I said it was a crazy idea, I threw it out just in case...

-Mike

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

Date: 3 Dec 92 09:08:17 GMT
From: Erik Max Francis <[e-mail]>
Subject: Voyager's "message"... What did it *say*?!?
Newsgroups: sci.astro,sci.space

[e-mail] (Rick Miller, Linux Device Registrar) writes:

> Are these facsimilies of spectrometer readings?  The codes along the
> radial lines of the starburst pattern are even *more* complex... and I
> can't make heads nor tails of the two circles linked by a line just above
> the starburst.

The "starburst" pattern is a representation of the nearest pulsars to
Earth and their distances, so that they can find us (eek).

I believe the two circles had to do with determining that the unit of
distance used throughout the plaque is 21 cm, the wavelength of neutral
hydrogen emissions . . .

----------
Erik Max Francis   Omnia quia sunt, lumina sunt.  Coming soon:  UNIVERSE _ | _
USmail:  1070 Oakmont Dr. #1 San Jose CA 95117  ICBM:  37 20 N  121 53 W _>|<_
UUCP:  ..!apple!uuwest!max   Usenet:  [e-mail]   464E4F5244   |

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End of Space Digest Volume 15 : Issue 499
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