Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO533.TXT

Internet Message Format | 1993-07-13 | 25KB

Date: Sat, 12 Dec 92 05:03:43
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #533
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 12 Dec 92       Volume 15 : Issue 533

Today's Topics:
              absolutely, positively overnight (6 msgs)
                 DC vs Shuttle capabilities (2 msgs)
                     Freeman Dyson biographies...
                            Saturn V fates
                       Scud Missile technology
       Terminal Velocity of DCX? (was Re: Shuttle ...) (2 msgs)
          WFPC-2 Will Magnify Hubble's Views of the Universe

    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: 10 Dec 1992 20:35:12 GMT
From: Anthony J Stieber <[e-mail]>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
>I hate to raise this, but are there ICBM proliferation concerns
>over open marketing of DCs? After all, it should have O(100 ton)
>payload for IRBM ranges and multiton payload for ICBM ranges
>and it can be arranged to come down hypersonically with what 1200 ft
>targetting accuracy?

Wouldn't it get real expensive real quick to use a billion dollar
spacecraft as a dumb throw away ballistic missile?  Although a DC-1
could certainly make a real nifty hypersonic ballistic bomber, I
haven't heard of any studies on releasing munitions at hypersonic
velocities.  If it didn't release munitions up high enough, a DC might
end up landing too close to ground zero.

Of course, nearly any aircraft can be used as a bomber.

By the way what is the projected cost for a DC-X' or DC-1?  I wish
we didn't have to get information in bits and pieces.
--
<-:(= Anthony Stieber    [e-mail]   uwm!uwmcsd4!anthony

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

Date: Thu, 10 Dec 1992 20:58:11 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Anthony J Stieber) writes:

>By the way what is the projected cost for a DC-X' or DC-1?

A DC-1 could cost anywhere from $250M each to about $1B each (ROM).

It is important to note that the difference between these prices is
amortization of development costs. Slight increases in demand can produce
far larger decreases in cost.

>I wish
>we didn't have to get information in bits and pieces.

I'm doing my best. :-)

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------135 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 10 Dec 92 13:54:13
From: Steinn Sigurdsson <[e-mail]>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Anthony J Stieber) writes:

   In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
   >I hate to raise this, but are there ICBM proliferation concerns
   >over open marketing of DCs? After all, it should have O(100 ton)
   >payload for IRBM ranges and multiton payload for ICBM ranges
   >and it can be arranged to come down hypersonically with what 1200 ft
   >targetting accuracy?

   Wouldn't it get real expensive real quick to use a billion dollar
   spacecraft as a dumb throw away ballistic missile?  Although a DC-1
   could certainly make a real nifty hypersonic ballistic bomber, I
   haven't heard of any studies on releasing munitions at hypersonic
   velocities.  If it didn't release munitions up high enough, a DC might
   end up landing too close to ground zero.

If you've spent $100 billion on nuclear technology a billion
dollar throwaway ICBM is a small marginal extra. And unfortunately
I can think of several scenarios where a uninterceptable one off
delivery vehicle would just the item required...

   Of course, nearly any aircraft can be used as a bomber.

Yup, but DCs would probably be lousy. As you noted hypersonic release
is non-trivial. Hence use it as an unmanned ICBM (hell, make it
manned, I could imagine some volunteers - although they might make
lousy pilots by definition) - but just set if for an airburst
using the altimeter...  hell, if Gary is right all they'd have to
do is hover over downtown for a few seconds ;-)

|  Steinn Sigurdsson    |I saw two shooting stars last night        |
|  Lick Observatory    |I wished on them but they were only satellites    |
| [e-mail] |Is it wrong to wish on space hardware?        |
| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

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

Date: Thu, 10 Dec 1992 21:48:29 GMT
From: Henry Spencer <[e-mail]>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Anthony J Stieber) writes:
>By the way what is the projected cost for a DC-X' or DC-1?

I doubt that anyone has a good handle on DC-1 purchase prices yet.  There
is no *fundamental* reason why it should be more expensive than a small
airliner (say $25M).  With the exception of the thermal protection, the
materials are things that are already being used in that market or are
about to enter it.  The vehicle is not overly large.  The avionics are
not far from commercial-aircraft stuff.  The engines are probably grossly
expensive by aircraft standards because of small production volume, but
one would hope that a substantial DC-1 production run would help that.

Initial price maybe that of a 747 ($150M)?  Seems a plausible guess.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Thu, 10 Dec 1992 21:55:44 GMT
From: Henry Spencer <[e-mail]>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
>I hate to raise this, but are there ICBM proliferation concerns
>over open marketing of DCs? After all, it should have O(100 ton)
>payload for IRBM ranges and multiton payload for ICBM ranges
>and it can be arranged to come down hypersonically with what 1200 ft
>targetting accuracy?

It doesn't *quite* have the right capabilities, because it's not capable
of hypersonic descent to low altitude.  Spacecraft and warheads have very
different thermal protection.  Spacecraft do almost all their decelerating
at very high altitude in very thin air, where thermal loads are manageable.
Warheads want to keep as much velocity as possible, and can afford to just
postpone the thermal loads because after detonation it won't matter.

However, I imagine you could take it up into a suborbital hop, kick a few
warheads out the door, and then do another burn so you land somewhere else.

It probably will be subject to missile-proliferation rules, at least at
the start.  If spaceships start becoming common, then limited missile
defences are probably going to become common too.  (They have to anyway,
because building a V-2 equivalent is no longer that difficult.)
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Thu, 10 Dec 92 22:58:26 GMT
From: Doug Mohney <[e-mail]>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Anthony J Stieber) writes:
>  Although a DC-1
>could certainly make a real nifty hypersonic ballistic bomber, I
>haven't heard of any studies on releasing munitions at hypersonic
>velocities.

You shouldn't. :-).

But they didn't call the SR-71 the Recon-STRIKE-71 before LBJ's mangling for
nothing.

                 Play in the intelluctual sandbox of Usenet

  -- >                  [e-mail]                        < --

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

Date: Thu, 10 Dec 1992 20:53:38 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: DC vs Shuttle capabilities
Newsgroups: sci.space

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

>From the vague descriptions I've seen, the cargo bay would seem to
>lack elementary things like an air lock.

True but the doors can open in space.

>Does that mean that passengers
>would ride up in a spacesuit and debark to a station?

Depends. Remember how they do payload integration. They provide
standard interfaces and you build to that. If you need an airlock,
just build it so it works with their pallet.

>That plus the
>short on orbit time seems to mandate an operating space station as
>destination.

Or satellite deployment/retrieval.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------135 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 10 Dec 92 22:13:12 GMT
From: Henry Spencer <[e-mail]>
Subject: DC vs Shuttle capabilities
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>Large payloads can go up in pieces for in-orbit assembly.  In fact, if
>>you believe Fairchild's old Leasecraft study, this approach is superior...
>
>Yeah, but I also remember how much harder in space assembly has turned
>out to be than was originally expected. Hopefully they'll get better
>at it with experience...

Note also:  in-space assembly so far has been done in spacesuits, which
is one of the big obstacles.  Doing it in a pressurized hangar ought to
be a lot easier.

(Actually, there are a few operations for which you'd prefer to work in
spacesuits.  If you will insist on using vile gunk like hydrazine as
fuel, fuelling [say] Cassini ought to be considerably safer in vacuum
with the fuelling crew in spacesuits.)

>... Anything
>much beyond simple mating of standard modules in space is probably
>stretching things too far...

I'm inclined to agree.  On-ground labor is still quite a bit cheaper than
in-space labor, even with very favorable assumptions about DC-1 or whatever.
Plugging the boxes together, okay.  Emergency troubleshooting, okay.  But
the birds will still be built on the ground.

>>DC-1's cargo bay will easily hold more crew than the shuttle can carry.
>
>From the vague descriptions I've seen, the cargo bay would seem to
>lack elementary things like an air lock. Does that mean that passengers
>would ride up in a spacesuit and debark to a station?

The cargo bay of the vehicle proper is just a box with doors; I don't
think it's even pressurized.  You pop a prefabricated crew compartment,
which can have airlocks etc., into it.

Personally, I think riding up in spacesuits is not a ridiculous idea,
given that you expect to reach a pressurized destination in short order.
But it's less than ideal for a number of reasons, not least being that
current spacesuits are heavy.

>That plus the
>short on orbit time seems to mandate an operating space station as
>destination. Now I like space stations, but we don't have one yet.
>Nor are we likely to have a functional one in the short timeframe
>until DC-1 is projected to be operational...

We should be able to have one very shortly after DC-1s become available.
There is no particular difficulty in building a space station within a
year or two, if transport is cheap and you deal with a construction
company rather than an aerospace contractor.  (The one from the a.c.
will weigh much less, if you don't count the paperwork, but will cost
a lot more and take rather longer.)  The incredible cost and schedule
of SSF are because (a) it is THE space station rather than A space
station and (b) every gram is precious.

>... With the crew
>cabin in the middle, docking with a station would seem very difficult.

Not really.  The shuttle's station docking point is also in its middle.
You just approach sideways, so you can see what you're doing.

>That's an interesting question anyway. How is docking with Freedom
>supposed to be handled?

Unless it's changed since I saw it described, basically the shuttle gets
close, and then the station's arm reaches out, grabs it, and moves it
into position.  For some of the early assembly, it'll be vice-versa with
the shuttle arm doing the work, but the shuttle arm isn't strong enough
to move the whole shuttle around routinely.

This makes considerable sense, in general.  For routine use, you want a
docking method that tolerates considerable error.  Getting within the
"capture volume" of an arm is a lot less fussy than making the docking
yourself.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Fri, 11 Dec 92 13:56:11 -0600
From: [e-mail] (Phil G. Fraering)
Subject: Freeman Dyson biographies...

\Check out some work that Freeman Dyson did.  He proposed genectically
/altering tress so that moiture loss could be controlled and then
\planting them on comets.  (Hey Nick, have I got a job for you! :-)

/Also, for a good read, check out "The Starship and the Canoe" a biography
\of both Freeman Dyson and his son Chris.  Talks about Freeman's work on
/Daedelus.

I've read it. It's passable in most parts, but altogether it's horrible.
The author feels so much more morally superior to both Dysons but
apparently especially to Freeman Dyson himself.

I was also disturbed by the general attitude its author seemed to
have towards people working in the physical sciences and/or engineering.

If you want to read a good biography of Dyson, that is fair and
still (IMHO) doesn't pull any punches, try the biographical parts
scattered through his own works. They're better written, more fun,
and also have a lot of good ideas, _firsthand_.

--
Phil Fraering
"...drag them, kicking and screaming, into the Century of the Fruitbat."
<<- Terry Pratchett, _Reaper Man_
PGP key available if and when I ever get around to compiling PGP...

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

Date: 10 Dec 92 23:48:27 GMT
From: Ross Allan Roberts <[e-mail]>
Subject: Saturn V fates
Newsgroups: sci.space.shuttle,sci.space

A question to cause further confusion... ;-)

Isn't there a SaturnV at Huntsville? Which one is this? I haven't seen any
mention of this one... I have a book simply entitled 'Apollo' that is real
good at explaining the missions and planning that went into the Apollo
project. Unfortunately, I just lent it to someone, so I have no other info
about it at the moment. When I get it back, I'll post enough info you
could find it at a library. It's a real good book. Looks at the missions
from more of the control room prespective, discusses design obstcles, and
special stuff such as the fire, 12's lightning strike, and of course 13.

 #############################################################################
#Ross Roberts ([e-mail])|'85 IT200, '81 MX100       #
#DoD#0340, still patiently awaiting the 6ooF2...  |'88 YFM350 Warrior         #
 #---------------------4-stroke good, 2-stroke gooder!---------------------- #
                    Friends don't let friends drive Suzuki's
#############################################################################

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

Date: Thu, 10 Dec 1992 20:51:23 GMT
From: George Wm Turner <[e-mail]>
Subject: Scud Missile technology
Newsgroups: sci.space

In article <[e-mail]>,
        Lawrence Curcio <[e-mail]> writes:

>Coincidentally, I roomed last year with a Russian Ph.D. physics student
>who was in the missile defense command in the army. He claims to have
>worked on one of the earlier scuds.
> [deleted]
>Anyway, the most amusing part was that he claimed the missile was
>programmed through the medium of *paper tape*. It's amazing they got any
>of those things off the ground :)

12 years ago, our military forces used paper tape to program some of its
strategic systems. its a medium that is radiation hardened, holds up well under
field conditions, and is easy to use by the crews.  the actual programming
is done somewhere else;  the paper tape only loads the program into the system.

 george wm turner   [e-mail]  [phone]

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

Date: Thu, 10 Dec 1992 21:00:08 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

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

>An SSTO has to haul all of it's engine and structure mass to orbit so
>these have to be lighter than a staged rocket that can discard engines
>and structure along the way. This is inherent in SSTO design. So a
>staged rocket can be made to have lower stresses than a SSTO for the
>same payload.

Except that there is absolutely no relationship between the size
(thrust) of an engine and the "stress" on it.  Robert Truax has
designed very large engines for his Sea Dragon (millions of pounds
thurst) with extremely *low* chamber pressures.  Faulty analogies
to race cars not withstanding.

>The wings impose a mass penalty,
>but that's offset by not having to carry landing fuel and it's tankage
>for VTOL operation.

No, it's not.  The mass of propellent required for a vertical landing
is much less than the weight of the wings.  The only way you can possibly
come out ahead is if you use the wings for lift on both takeoff and landing.

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

Date: Thu, 10 Dec 1992 19:51:38 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>In <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>
>>Look, I'm not trying to be dense here, but in circuit design we know
>>that the more parts you have in a circuit, and the harder you push
>>them, the more likely you'll have a failure. So you try to simplify,
>>and beef up what remains to stand the maximum expected stress.
>
>Well, obviously, then, you don't know anything fault-tolerant circuits,
>which increase the number of parts in order to reduce the probability
>of a failure.  Aircraft engineers were designing fault-tolerant and
>fail-safe systems before anyone even heard of electronic engineers.

And electrical engineers were building and operating multi-megawatt
power systems long before aircraft ever left the drawing board. We
know something about reliability engineering too. We like things simple
and robust. Every safety critical circuit has a separate backup, usually
using a different design that is unlikely to share common failure points.
Simple redundancy is all fine and good, but can lead to redundant failures.

Gary

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

Date: Fri, 11 Dec 1992 05:30:31 GMT
From: Ron Baalke <[e-mail]>
Subject: WFPC-2 Will Magnify Hubble's Views of the Universe
Newsgroups: sci.space,sci.astro

From the "JPL Universe"
December 4, 1992

JPL's new camera will magnify Hubble's views of the universe
By Diane Ainsworth

     Just weeks ago, the Hubble Space Telescope's all-purpose
"eyes" -- known as the Wide Field/Planetary Camera -- captured
the most detailed view ever of a galaxy's core, feeding a
suspected black hole in the Virgo cluster about 45 million light
years from Earth.
     "The nucleus is probably the home of a black hole with a
mass 10 million times that of our sun," said Dr. Walter Jaffe of
the Leiden Observatory in the Netherlands, whose findings were
published in the Astrophysical Journal. "This is our best view to
date of the immediate surroundings of the nucleus of an active
galaxy."
     While the performance of Hubble's Wide Field/Planetary
Camera-1 (WF/PC-1) has been hampered by a flaw in the curvature
of the telescope's primary mirror, the camera has nonetheless
produced some of the most awe-inspiring photographs of planets,
galaxies and exploding supernova ever taken.
     Now JPL's new second-generation Wide Field/Planetary Camera
(WF/PC-2) -- scheduled for launch as part of the Hubble Space
Telescope's servicing mission next December -- is in final
assembly and promises even more spectacular views of distant
galaxies in the universe. The new camera has been designed to
correct the optical flaw in the Space Telescope's 95-inch
(2.4-meter or 8-foot) diameter primary mirror.
     After installation, WF/PC-2, along with a second instrument
-- COSTAR, the Corrective Optics Space Telescope Axial
Replacement -- will restore the Hubble Telescope to its original
capabilities of imaging fine detail with high angular resolution,
photographing star clusters, detecting very faint stars, distant
galaxies and objects in the ultraviolet.
     An innovative approach to correct the error in the primary
mirror was incorporated in the design of the new secondary
mirrors of the Wide Field/Planetary Camera relay optics, said
Larry Simmons, WF/PC-2 program manager at JPL.
     "The WF/PC-2 incorporates optics that will internally
refocus the beam of incoming light from Hubble," he said. "We
corrected for the error in the curvature of the primary mirror by
creating an error of equal and opposite magnitude on the surfaces
of our WF/PC-2 relay optics. When the images reach the camera's
charge-coupled detectors (CCDs), the error will be reversed and
completely cancelled out."
     The Wide Field/Planetary Camera-2 actually consists of four
camera systems -- three wide-field cameras and one planetary
camera.
     The wide-field cameras provide extraordinary sensitivity for
the detection of star clusters and distant galaxies, while the
planetary camera performs high-resolution studies of individual
objects, including planets and their moons, nearby galaxies and
other stellar objects.
     As light enters the Hubble Space Telescope, it is bent at a
90-degree angle by a "pick-off" mirror and aimed into the Wide
Field/Planetary Camera. Design modifications in the new WF/PC
call for an adjustable pick-off mirror that ground technicians
will be able to tilt to align the light beam entering the camera.
     "The alignment of the pick-off mirror is critical to
correcting images," Simmons said.
     The light beam passes through one of 48 filters before a
pyramid mirror inside the camera splits the light into four
quadrants. Each of the four quadrants of light is relayed by
tiny, nickel-size relay mirrors -- the mirrors that JPL modified
to correct for the error in the telescope's primary mirror -- to
a separate detector called a charge-coupled device (CCD). CCDs
collect light in the same way that film collects light in a
camera, but with much greater sensitivity.
     "The corrected images are formed on the CCD sensors,"
Simmons said. "The CCDs we are using in the new camera will have
greater sensitivity and will allow the camera to see from the
ultraviolet to the infrared."
     The new Wide Field/Planetary Camera and the COSTAR axial
replacement instrument will restore Hubble's imaging performance
to nearly 100 percent of the original specifications. Currently,
the telescope is able to focus only 10 to 15 percent of the light
it receives within a diameter of 0.2 arc-second. Its original
performance goal was to focus 70 percent of the light received.
     The telescope was designed to provide three basic
capabilities: high angular resolution -- the ability to image
fine detail; ultraviolet performance -- photographing ultraviolet
images and spectra; and high sensitivity -- the ability to detect
very faint stellar objects.
     With its corrective optics, scientists expect the telescope
will be able to provide the highest sensitivity to detect objects
10 times fainter than those visible from Earth-based telescopes,
with about 10 times greater spatial resolution.
                                      ###
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     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.

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

End of Space Digest Volume 15 : Issue 533
------------------------------