Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO565.TXT

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Date: Fri, 18 Dec 92 05:05:31
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #565
To: Space Digest Readers
Precedence: bulk


Space Digest                Fri, 18 Dec 92       Volume 15 : Issue 565

Today's Topics:
                             Chase planes
                           DoD launcher use
                     fast-track failures (2 msgs)
          Greek jet engine (Was: Terminal Velocity of DCX?)
             Justification for the Space Program (2 msgs)
                           Making Orbit '93
                             Sea Dragon?
        Shut up about DC (was Re: DC vs Shuttle capabilities)
                      SSTO Concepts FAQ (2 msgs)
          Terminal Velocity of DCX? (was Re: Shuttle . . .)
                         Voyager UVS shutdown
                            Wither the ET?

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

Date: 17 Dec 1992 23:51:16 GMT
From: steve hix <[e-mail]>
Subject: Chase planes
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Claudio Egalon) writes:
>The chase plane that crashed with Valkyrie was being flown by Joe
>Walker, the pilot that broke so many records with the X-15. I was
>wondering if anyone in the net knows what was the reason for the
>crash. My first impression was that it was pilot error but I may be
>wrong.

Walker had insufficient experience in formation flying, got too close
to the B-70 and got caught by trailing wake turbulance, rolled over the
top of the B-70's near wing, took off a least one of the vertical stabs
and killed himself before the B-70 went down itself.

--
-------------------------------------------------------
| Some things are too important not to give away      |
| to everybody else and have none left for yourself.  |
|------------------------ Dieter the car salesman-----|

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

Date: 17 Dec 92 18:59:53 GMT
From: Doug Mohney <[e-mail]>
Subject: DoD launcher use
Newsgroups: sci.space

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

>>>. With a serious opponent, your space assets would be priority targets.
>>
>>So, uh, gary, where are the serious opponents supposed to afford A-SATs? hmm?
>
>The ex-Soviets have a system. Getting into a fight with them would still
>be dealing with a serious opponent in my book.

Yes, but you imply there's more than the Russians who have ASAT. Could you
illustrate who else has demonstrated said technology? And describe the CURRENT
state of the SS-9s (?) which were used to pitch them up?


They had that capability. Whether it still exists is open to question.

Besides, the Russians are our friends. We're buying reactors and science data
and a good portion of their research establishment with good old Yankee
Dollars.

>>If you can kill recon planes, it's damn sight harder to kill sats.
>
>In principle no, the sats are predictable, the planes aren't. Putting
>some "buckshot" in their orbital path is sufficient to knock them down.
>In practice planes probably are easier to down because few countries
>have space launch capability while they do have AAA, but most planes
>in combat zones aren't shot down, and planes are cheaper than spysats too.

Depends on what type of plane. The RF-16s are, oh, how much these days?
$16-20 million?

>>Furthermore, you assumed that the KH-11 is the benchmark (also known as
>>the Szabo yardstick) without the resultant drop in costs which would occur if
>>you could rapidly deliver sats to orbit.
>
>Launch costs don't dominate a spysat's cost, at least not one capable of
>doing tactical damage assessment. The cost is dominated by the superior
>optics required for a orbital spy versus the optics required for an aircraft,
>and by the flight control systems required to point the thing at the right
>place and compensate for orbital motion and downlink the data. An aircraft's
>photorecon equipment is much cheaper because the optics don't have to be as
>good because of the lower altitude, the pilot takes care of pointing chores,
>and the data is physically returned at the end of the mission.

Gary, depending on who you listen to, the KH-12 costs between $800 mil and $1
billion dollars, but it's also a LOT of hardware and fuel to make sure it stays
up there for a long long time.

Now, SPOT gets 5-10 meter resolution and costs some number ($150-200 million?)
below that. A follow-on to SPOT with 1-2 meter resolution will probably cost
the same...

You CAN build a cheap sat with the resolution needed to do tactical damage
assessment. The ex-Sovs did it all the time; they used film rather than
rad-spec hardened long-life electronics to transmit images back. You can go
cheap on the electronics if you don't want your spysat to live for 5-7 years.

                    I have talked to Ehud, and lived.
  -- >                  [e-mail]                        < --

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

Date: Thu, 17 Dec 92 20:47:10 GMT
From: Dave Jones <[e-mail]>
Subject: fast-track failures
Newsgroups: sci.space

Pat ([e-mail]) wrote:
>
> Actually another case was the YB-49  and YB-50?  those were
> northrops  flying wing prototypes,  the turbo-prop  and the jet versions.
>
> They actually flew but had trouble with range,  and power.  the prop job
> needed twin counter rotating props to really develope thrust.
>
> Plus there were enormous political problems witht he Air Force on the
> birds.  Too bad,  the effort broke jack northrop  and he never got to
> see his vision carried off in the B-2.

Actually he was given a look at a B-2 model while it was still a black
program.  His reported words were "Now I know why I got to live so long".

--
||------------------------------------------------------------------------
||Dave Jones ([e-mail])|Eastman Kodak Co. Rochester, NY  |

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

Date: 17 Dec 1992 23:47:34 GMT
From: steve hix <[e-mail]>
Subject: fast-track failures
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Pat) writes:
>
>Actually another case was the YB-49  and YB-50?  those were
>northrops  flying wing prototypes,  the turbo-prop  and the jet versions.

Almost.  The B-50 was from Boeing, mostly a tricked-up B-29.

Northop's YB-35 was prop flying wind.

YB-49 was jet-powered version.

>They actually flew but had trouble with range,  and power.  the prop job
>needed twin counter rotating props to really develope thrust.

The YB-35 was designed to carry 10,000lb load 7,500 miles (with a
remaining 15% fuel reserve), economy cruise of 183mph gave it a range
of 8,125miles.  Top speed was 393mph at 35,000', service ceiling was
40,000'.  Not too shabby for a 40's bomber.

*Nobody* had much luck with counter-rotating props (save a handful such
as the Shackleton and Spitfire XXII).  Using them meant that you could
get by with a smaller prop diameter for a given powerplant, and they
provided more yaw stability...but the stupid gearboxes never worked.

The YB-35A switched to normal single props.  The XB-35's were converted
to single four-bladed props because of the gearbox problems.

The jet (YB-49) had only about a 2,800 mile range...but nobody at the
time was getting much range out of jets.  And the J-35 wasn't the
greatest jet engine ever made.

>Plus there were enormous political problems witht he Air Force on the
>birds.  Too bad,  the effort broke jack northrop  and he never got to
>see his vision carried off in the B-2.

Ain't politics wonderful.

--
-------------------------------------------------------
| Some things are too important not to give away      |
| to everybody else and have none left for yourself.  |
|------------------------ Dieter the car salesman-----|

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

Date: Thu, 17 Dec 1992 18:47:00 GMT
From: Roger Wilfong <[e-mail]>
Subject: Greek jet engine (Was: Terminal Velocity of DCX?)
Newsgroups: sci.space

In Article <[e-mail]> "[e-mail] (Dillon Pyron)" says:
>
> Imagine a sphere, mounted on an axle.  Place a nozzle perpendicular to the
> axle, fill the sphere with water and light a fire underneath.  If the nozzle is
> L shaped, you can make the sphere spin.  The porblem is, if the water is not
> hot enough when it starts to spin, the rig will stall at the bottom, water will
> gush out and kill the fire.
>

You can get rid of this problem by extending the tube(s) into the sphere
about 1/3 of the diameter of the sphere.  That way it stays above the water
level and the liquid water doesn't spray out.

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

Date: 17 Dec 92 22:12:02 GMT
From: [e-mail]
Subject: Justification for the Space Program
Newsgroups: talk.politics.space,sci.space

> In article <[e-mail]>, [e-mail] (Judy McMillin) writes:
> |>
> |>      Can any of you think of any moral or philosophical justification
> |>     for using huge amounts of taxpayer money to fund the "space
> |>     program" at all?  Not counting, of course, it provides high-
> |>     pay, high-tech jobs for a bunch of us.
>
How about, "If we want to avoid the fate of the dinosaurs, at some time in the
future (never mind that it might not be in OUR lifetimes), then we better
get something up there that can track every asteroid, and comet.  Better yet,
we better build something that can deflect one of these at some time in the
future."

The fact that this implies space science, and a good launch system, and several
other things is secondary.  This is the long term human survival approach.
Note:  It works VERY well with people who have small children, or who are
thinking about having children.  (I know, I have a small child, and I think
about the long term survival of the race in conjunction with thinking about her
growing up, and having kids of her own.)

            John.

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

Date: Thu, 17 Dec 1992 21:29:53 GMT
From: Jared Dahl <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: alt.rush-limbaugh,talk.politics.space,sci.space

In article <[e-mail]>, [e-mail] (Judy McMillin) writes:
|>
|>      Can any of you think of any moral or philosophical justification
|>     for using huge amounts of taxpayer money to fund the "space
|>     program" at all?  Not counting, of course, it provides high-
|>     pay, high-tech jobs for a bunch of us.

Sure.  Very easy.  How about, "Where do we go now?"  We've
been everywhere on this planet, it's time to start exploring
everything else in the universe.  Let's go see what's on Mars,
or the moons of Jupiter.

We started out in Africa, and spread slowly all around the world.
We have moved from walking to riding animals to ships to cars
to aircraft.  Why not take the next logical step in our evolution?
We have always been curious explorers, and we can't change our
nature now.

Jared Dahl
Opinions expressed are mine, not my employer's.
Don't send e-mail - I won't get it.

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

Date: Thu, 17 Dec 1992 21:37:36 GMT
From: "David W. Berry" <[e-mail]>
Subject: Making Orbit '93
Newsgroups: rec.arts.sf.announce,sci.space

        M     M      A      K   K  IIIII N    N   GGGG
        MM   MM     A A     K  K     I   NN   N  G    G
        M M M M    A   A    KKK      I   N N  N G
        M  M  M   AAAAAAA   K  K     I   N  N N G    GGGG
        M     M  A       A  K   K    I   N   NN  G    G
        M     M A         A K    K IIIII N    N   GGGG

               OOOO   RRRRR  BBBB  IIIII TTTTTTT       9999   333
              O    O  R    R B   B   I      T         9    9 3   3
             O      O R    R BBBB    I      T         9    9   33
             O      O RRRRR  B   B   I      T          99999     3
              O    O  R   R  B   B   I      T              9 3   3
               OOOO   R    R BBBB  IIIII    T          9999   333


Making Orbit Conventions is proud to announce Making Orbit '93!

It is a fact that most Americans support the idea of a sound space program
that gets real people out into space to do real work. Yet, how far have we
really come toward making that a reality? What is being done to make that
happen? What are the most promising technologies? Will we really get real
people to space soon? Is there anything individuals can do to help make
space living attainable for everyone? Are rocket launch systems the way to
get there? Or are there other viable launch systems? How much of an
influence does science fiction have on science fact and vice-versa?

These are just a few of the questions we hope to address at Making Orbit
'93, a space oriented hard science and science fiction convention sponsored
by Making Orbit Conventions and Space Access Society. Along with answering
these weighty questions, we also intend to have some fun along the way. A
forum will be provided for many organizations so that information can be
shared and enthusiasm for space can be rekindled. This is your chance to
share ideas with the experts who are forging the path to the stars, and the
science fiction writers who have been furnishing us with dreams.

The convention will begin Friday afternoon with two program tracks. One
will be a segment sponsored by the Lunar Society, featuring space oriented
curriculum ideas and guides for educators. The other will be a mixed track
of lighter programming. Then in the evening we really get down to business
with an opening ceremony, participant reception and cash bar where you can
meet all our speakers. On Saturday and Sunday there will be three
programming tracks all featuring space oriented subjects. Two of those
tracks will be oriented to hard science and space information with a
special emphasis on alternate launch technologies and space policy. A third
will be a lighter "Sex in Space" track. On Monday we expect things to wind
down but there will still be lots to do. To round things out, in addition
to our panels, there will be a dealers' room, art show, and evening
hospitality to allow you to share ideas in a more informal atmosphere.

We welcome any suggestions you have that would make this event more
interesting and fun for you. Please feel free to call us with your ideas
for guests, programs or other features. For further info and memberships
contact Making Orbit, 909 Marina Village Parkway #237, Alameda, CA 94501 or
[phone].

All this fun and information will be shared in the wonderful atmosphere of
the Berkeley Marina Marriott. The hotel features two pools (one is adults
only), a large spa, and health club, all set in a peaceful nook right on
the waters of the San Francisco Bay in the Berkeley Marina. And all of this
at the great convention rate of $79 per room. For hotel info and
reservations contact the Berkeley Marina Marriott, 200 Marina Blvd,
Berkeley, CA 94710, [phone].

Speakers Already Planning to Attend Include
        Max Hunter - Rocket Designer
        Jerry Pournelle - SF Writer
        Larry Niven - SF Writer
        G. Harry Stine - Science/SF Writer
        Gary Hudson - Space Entrepreneur
        Jordin Kare - Laser Launch
        Steve Hoeser - Space Technologist
        Jim Ransom - Lunar Society
        Tim Kyger - Congressional Advisor
        Art Bozlee - Soviet Space Expert
        J. P. Del Fevero - Space Economics
        William Gaubatz - SSTO
        Rick Jurmain - SSTO

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

Date: Thu, 17 Dec 1992 14:17:18 GMT
From: Dennis Newkirk <[e-mail]>
Subject: Sea Dragon?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Scott Fisher) writes:
>[e-mail] (Dennis Newkirk) writes:
>>lift-off weight 45,360,000 kg.
>                 ^^^^^^^^^^^^^
>                 |||||||||||||
>                 No way :-)    Perhaps it's living in a place that uses pounds
>that has confused you?  Using my calculator to convert to pounds (weird units
>you guys use in the US) that comes to... 100,001,682 pounds...now that means
>very little to me but 45 million kg sure sticks out like a sore thumb to my
>metric eyes :-)

I think you are the confused one...

That is a big number. It's also the weight published in both
pounds and kilograms in the Congressional Research Service book
I referenced. Check out the quote below.

>>2 stage, water launched, pressure fed motors.
>>both stages reusable
>>recovered by unaided atmospheric and hydrodynamic deceleration only
>
>Does this mean they are allowed to free-fall back to earth and splash?

That was the idea.

Here's info on what must be an early Sea Dragon idea, its not quite
the same as in the other reference.

From : SPACE CARRIER VEHICLES
Design, Development, and Testing of Launching Rockets
By: Oswald H. Lange and Richard J. Stein
Saturn Systems Office
George C. Marshall Space Flight Center
National Aeronautics and Space Administration
Academic Press, New York, 1963
Advances in SPACE SCIENCE and TECHNOLOGY
Edited by Frederick I. Ordway, III
Editorial Advisory Board
Wernher von Braun
Leslie R. Shepherd
Frederick C. Durant, III
George P. Sutton
Eugen Sanger
Etienne Vassy

p.297-298

"The Aerojet-General Corp.in particular has studied a scheme
to launch a 600-ft high, three-stage vehicle, weighing 50,000 tons and
developing 130,000,000 lb of thrust. The vehicle envisioned would be
assembled in a drydock, as pictured in Fig. 221, and towed to the launch
site. At the launch site a specially constructed flat-top ship would move
into position to act as a service platform.  Erection of the vehicle was
planned by flooding the launch pontoon as shown in Fig. 222.  Fueling and other
pre-launch operations would then take place.  Upon launch readiness, the
flat top tender would be removed, and the carrier vehicle fired from its
supporting pontoon."


Dennis Newkirk ([e-mail])
Motorola, Land Mobile Products Sector
Schaumburg, IL

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

Date: 17 Dec 92 14:39:31 -0600
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Shut up about DC (was Re: DC vs Shuttle capabilities)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Greg Moore) writes:
> In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>>Depends on your assumptions.  I've done some back-of-the-envelope
>>calculations.  If you can set up an oxygen-extraction plant on the
>>Moon, your costs go way down if you land the DC with its LOX tank
>>dry.
[...]
>     Right, that works fine once you've built your power-plant
> on the moon.  I'm talking at first.  It seems to me that someone
> here is forgetting the middle step of testing and flying the thing.

Greg is right.  Everyone on the Net should refrain from speculating on
the potential applications of the DC series and its derivatives until
all these spacecraft are tested and flown.

Sheesh.

Bill Higgins, Beam Jockey              | "Enough marshmallows
Fermi National Accelerator Laboratory  | will kill you
Bitnet:           [e-mail]  | if properly placed."
Internet:       [e-mail]  | --John Alexander, leader of
SPAN/Hepnet:           43011::HIGGINS  | "disabling technologies"
 [*Aviation Week*, 7 Dec 1992, p. 50]  | research, Los Alamos

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

Date: 17 Dec 92 23:41:13 GMT
From: Steinn Sigurdsson <[e-mail]>
Subject: SSTO Concepts FAQ
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:


   13. How often will the SSTO be able to fly?
   The anticipated turn-around will be about 1 day.

Hmm, last figure was two guys(? - Henry you quoted that)
to handle the fuelling. Consensus was LOX/LH2 trucks carried
about 3 tons, we need 300 tons total - that's 100 trips
to your tank farm (which I claim damn well better be over two
miles from your launch pad) or about 15 minutes per trip
including pumping at each end! Don't think so, even assuming the
crew can operate without error for a 24 hour shift (and I ain't
going near a LOX truck hooked up by someone who hasn't slept for 24
hours...).

So, is turnaround slower or are the ground crew estimates a leetle
optimistic? Sounds to me like 12 people on refuelling alone will
be necessary for 24 hour turnaround?


BTW how does the DC to heat management in orbit? The shuttle
has what half-dozen complementary systems, at least one of which
forces an abort if it fails? What does the DC do (assuming two days in
orbit quoted here is the requirement)?

|  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: Fri, 18 Dec 1992 01:25:52 GMT
From: Paul Dietz <[e-mail]>
Subject: SSTO Concepts FAQ
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:

>to handle the fuelling. Consensus was LOX/LH2 trucks carried
>about 3 tons, we need 300 tons total - that's 100 trips


That's wrong -- the figure was that LH2 tankers carry 3 to 5
tons, but we said nothing about LOX tankers.  LOX is much more dense
than LH2, and most of the mass of the propellant is LOX.

    Paul F. Dietz
    [e-mail]

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

Date: 17 Dec 92 16:58:00 PST
From: "RWTMS2::MUNIZB" <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle . . .)

My apologies to the net if this has been discussed before, but I've been
pretty far behind in my reading.  Anyway, . . .

In article <[e-mail]> [e-mail] (Gary
Coffman) writes:
>tested. Later it intends to use aerospike engine designs that have
>*never* been tested, even on the ground. It will be difficult for

This is definitely not true!

On Date: Thu, 19 Nov 1992 15:04:00 GMT, "Allen W. Sherzer" <[e-mail]>
writes:
>conventional bell nozzles. The GD design could enter base first but had
>to have an aerospike nozzle to do it. Since aerospike nozzles have never
>flown, that would add another risk to the propulsion system.

This is more correct, but not the total story either.

In the Spring 1992 (No. 8) issue of Rocketdyne's *Threshold* magazine
there is an article "Nozzle Design" by R. A. O'Leary and James E. Bech
which states "During the 1960's, Rocketdyne tested numerous aerospike
engines, ranging in size from subscale, cold-flow models to this
250,000-pound-thrust oxygen/hydrogen shown at a test stand in Nevada
(picture of engine firing).  The low altitude performance advantage of
the aerospike over conventional bell nozzle is clearly seen".  The curve
presented looked like this:

             1.0 .----.----.----.----.----.----.----.----.----.----.
                 |            + T  +T T   +   +/   +/   +/   +/ T +/
                 |    T +                   /
                 :  +                    /
                 |                    /
             0.9 |                  /
                 :                 /      Area Ratio = 75:1
  Nozzle         |                /       nozzle length = 25% equivalent
  Efficiency     |              /                         conical
                 :              /
             0.8 |            /            /  Bell Nozzle
                 |           /             +  Aerospike (predicted)
                 :          /              T  Aerospike (test data)
                 |         /
                 |
             0.7 :----.--/-.----.----.----.----.----.----.----.----.
                 |      |     |     |     |       |     |       |
                 10    100   200   400   800    2000  4000    10000

                             Pressure Ratio:  Pc/Pa

Various propellants and both conical (1-D) and axial (2-D) models were
been tested.  I have heard from several sources that Rocketdyne's
original proposal for the Space Shuttle Main Engines used an aerospike
design.  At the California Space Development Conference held in San Diego
in February 1991, Vern Larson from Rocketdyne gave a presentation on the
aerospike test program.

At that same conference, I asked Max Hunter ("father" of the Delta rocket
and a major player in the SSTO field) why it seemed that an aerospike was
not baselined for the DC-X or the proposed DC-Y and DC-1.  He replied
that there was concern regarding the lack of *flight-test data* (he
acknowledged that there was plenty of ground test data), in particular
for the transonic regime.  However, the Rocketdyne article states ". . .
from Mach 1 to about Mach 3, *wind tunnel tests* (emphasis mine) indicate
a drop in nozzle efficiency due to the slipstream turning into the nozzle
region . . . Nevertheless, the interval of time that is spent in this
adverse flight regime is short for typical flight trajectories, and
overall performance of the aerospike nozzle remains well above that of a
conventional bell-type nozzle".

Wind tunnel test results and CFD simulations are usually sufficient for
design of experimental flight vehicles.  Therefore the question remains:
If lack of *flight-test* data is seen as the long pole in the tent
(holding things up), why isn't it being flown on the admittedly
experimental DC-X (and DC-Y)?

A reference on aerospike engines that I've seen noted but haven't had a
chance to get is: Ballard, R. O., "The Aerospike/Aeroplug Engine: A
Technology Development Summary", Sverdrup Technology Inc., MSFC Group,
Contract NAS8-37814, 1991.

In regards to technology for SSTO, I came across an article by C. E.
Tharratt of Chrysler Corporation Space Division in JBIS Vol. 28, pp.3-25,
1975, entitled "SERV - A Reusable Single Stage to Orbit Space Shuttle
Concept".  It says that a reusable SSTO could be built to NASA
requirements with the technology level of the day, except for an added
"requirement for large cross range (1500 nautical miles with crew and
cargo) and through it, the ability the ability to launch and land in one
earth orbit."

I seem to recall this as an Air Force driven requirement, and that the
original NASA requirement was less stringent.  The paper states the
original requirement as a return to a preselected [launch?] site every 24
hours (approximately 15 orbits), rather than one orbit.  Any idea what
the requirement will be for DC-Y (and DC-1)?

In order to meet the cross range requirement, the article mentions the
weight benefit of using a reusable reradiative heat shield (todays
Shuttle tiles) rather than the baselined ablative material, and a major
advance in specific impulse from using an activated oxygen/hydrogen
engine with a 650 second vacuum specific impulse.  It ruled out weight
reduction based on materials technology (which today is a most  viable
technology!).

Ben Muniz: President, Rocketdyne Employees Space Society/a chapter of NSS
Internet:[e-mail]  w(818)700-5549  h(818)346-6647

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

Date: 17 Dec 92 15:44:09 -0600
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Voyager UVS shutdown
Newsgroups: sci.space,sci.astro

In article <[e-mail]>, [e-mail] (Jayant Murthy) writes:
> The Voyager Ultraviolet Spectrometer (UVS) Guest Observer (GO) Program
> Scientist, Bob Stachnik/NASA HQ and the UVS GO Project Scientist, Ron
> Oliversen/GSFC regretfully announce the termination of the UVS GO program.

Ouch!  Bummer.

The UVS has quietly been observing stellar spectra in the far
ultraviolet for many years.  To give this announcement some context,
I append excerpts from a 1990 posting I wrote.

There was an article by J.B. Holberg and others giving results from
the UVS observations in *Journal of the British Interplanetary
Society* in the past year or so; sorry, don't have the citation handy.

==============================================

Now that all the planets on the Voyagers' itinerary have been passed,
some of their instruments are essentially useless.  The imaging and
infrared spectroscopy gadgets have nothing close enough or bright
enough to look at anymore.  As a one-time stunt (I almost said
"one-shot," but then remembered it's a mosaic (-:), Voyager 1 snapped
the "family portrait" showing the bodies of the Solar System as little
dots.  Data are back on the ground, and we oughta see the result any
week now.  The final frame of the portrait showed the Sun, and in
taking it solar heat may have damaged the shutter of one camera
permanently.  That's okay-- Voyager 1 will never need that camera
again.  (Barring flying saucer visits.)  If there is a scientific
purpose to the family portrait, I'm not aware of it.  But it's a nice
thing to have.

Other instruments aboard continue to gather interesting information,
which is what JPL means by "routine cruise science."  The
particles-and-fields stuff reports on the environment at the edge of
the solar system; examples include the Plasma Wave System, the
Magnetometer, and Low Energy Charged Particle instrument.  As the
plutonium in the generators decays and power runs low in the years to
come, instruments and their heaters will be shut off, starting with
the cameras.  But the Voyager gang hopes to hit the heliopause-- the
boundary between the solar wind and the interstellar wind-- in the
next decade or two.  So they'll need as many of the P&F experiments
running as they can manage.

One special case is the Ultraviolet Spectrometer (UVS), which sits on
the scan platform with the cameras and the infrared spectrometer.  Its
primary purpose is for looking at ultraviolet emission and absorption
lines in the atmospheres of planets.  It is sensitive to wavelengths
in the "extreme ultraviolet," between 500 and 1700 angstroms.

It happens that not much astronomy has been done in these
wavelengths.  The galaxy has clouds of interstellar hydrogen.  A
"Lyman alpha" photon (912 angstroms, 13.6 electron volts) has enough
energy to ionize neutral hydrogen. Any photon of wavelength *shorter*
than this runs the risk of bumping into a hydrogen atom and getting
absorbed as it knocks the electron loose.  Now, there is not much
hydrogen in interstellar space.  There's a lot of room between
hydrogen atoms.  But over trillions upon trillions of kilometers, the
hydrogen adds up.  Beyond a few light-years, it's hard to see any
light with really short wavelengths, because it gets absorbed in the
interstellar hydrogen before it gets to us.

Consequently, the ultraviolet telescopes that have flown in space,
such as the International Ultraviolet Explorer, have not been given
the capability to see extreme ultraviolet (EUV) colors.  But the sky
isn't as opaque as people thought;  you can see *some* distance into
space in the EUV, and there is interesting physics going on in nearby
stars, especially extremely hot ones.

The Voyager UVS instruments are the only currently flying which can
make measurements in the EUV.  They are small, and their spectral
resolution is only about 100 angstroms, but they have lots of leisure
time to make long exposures these days.  So there's an ongoing program
to use the UVS to study a series of stellar targets, which, I imagine,
will continue as long as they have the power to operate them.   [Hah!
--WSH, 1992] I'd speculate that the Voyager studies are valuable
precursors for planning such missions as the STS-35 ASTRO observatory,
carrying the Hopkins Ultraviolet Telescope [it flew once, and will fly
again --WSH, 1992], and the Extreme Ultraviolet Explorer, which will
make an all-sky survey.

     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
 /       \                          (_) (_)                    / | \
 |       |     Bill Higgins   Fermi National Accelerator Laboratory
 \       /     Bitnet:     [e-mail]
   -   -       Internet:  [e-mail]
     ~         SPAN/Hepnet:      43011::HIGGINS

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

Date: 17 Dec 1992 20:07:30 GMT
From: Pat <[e-mail]>
Subject: Wither the ET?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Josh 'K' Hopkins) writes:
>or is ET use to remain forever a dream?  Did the SOFI (Spray On Foam Insulation)



I saw a preseentation on uses for the ET's, and asked about the insulation
problem.  THe response was, that given the low density of the insulation and
the presence of atomicx  oxygen, any kernels  would not last more then
14 days in orbit, an acceptable level of problem reduction.

Now my gut instinct is that the best way to use the ET's  would be in a
wet workshop configuration,  ALA skylab.   rig the tanks with either
Airlocks,  or hardpoints for airlocks,  and put flooring and racks
in,  flooded in the LOX/LH2.   then just carry cargo in the Shuttle
Bay and load it in, before you put an atmosphere in.

they also had lots of applications, using the tanks as carriers.
put a truss on hte tank, and then hang stuff off the truss.

i saw it, but i couldnt see people going for 2 week expendable space craft.

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End of Space Digest Volume 15 : Issue 565
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