Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO537.TXT

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Date: Sat, 12 Dec 92 05:17:41
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #537
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 12 Dec 92       Volume 15 : Issue 537

Today's Topics:
              absolutely, positively overnight (2 msgs)
              Cassini Undergoes Intensive Design Review
                           DoD launcher use
                    Hubble's view of the universe
                      Magellan Update - 12/11/92
              Mariner 2 Radiation Experiments - 12/28/62
                   Mars Observer Update - 12/11/92
                           Orbit Question?
                       Scud Missile technology
        Soaring like and Eagle (was Re: Range Safety and DC-X)
                        spaceships as missiles
           Terminal Velocity of DCX? (was Re: Shuttle ...)
                      Ulysses Update - 12/11/92
                           What is a VSAT?
                   what the little bird told Henry

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

Date: 11 Dec 92 17:24:37 GMT
From: Gary Coffman <ke4zv!gary>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
[on jet lag]
>However, on closer examination, trip time is relevant... because a long
>fatiguing trip can only make the problem worse.  The shorter the better.

That depends on trip direction. Getting some sleep on the plane can ease
jet lag if you are heading into morning.

>I'm sure that if certification were suitable and appropriate facilities
>were widespread, there'd be a few executive DC-1s bought.  The Saudi
>royal family would surely buy one.  And then there's Air Force One...

Take a look at Air Force One, or Two. A 747 and a 707. The Air Force
is very conservative in the choice of aircraft on which to fly the
President. The Saudi royals are even more conservative. Maybe a
playboy nephew might be allowed on a high performance aircraft,
but none of those directly in line for the throne. Give DC 20
years of routine passenger carrying flight experience, then if
it's record was good enough, maybe.

Gary

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

Date: 11 Dec 92 19:01:00 GMT
From: Pat <[e-mail]>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Josh 'K' Hopkins) writes:
>
>>... On the subject of expense, the Concorde seems a
>>good example.  It's never been profitable enough to make anyone else want to
>>buy one and it's at least 1.5 orders of magnitude cheaper than I can see a DC
>>type vehicle being.  So where's the motivation for passenger travel?
>
>(I assume we're talking about surface-to-surface travel, not surface-to-space,
>which is a very different market with a proven audience.)  I don't see DC-1
>as a surface-to-surface passenger vehicle to any great extent.  Prices would
>be high enough that you'd get only the cost-is-no-object crowd:  the really
>rich and the people whose time is really valuable.  I suspect you could make
>money by buying a couple of DC-1s, going all out on luxury interiors, and
>running them on a charter basis.  It doesn't seem a promising basis for
>regular scheduled service, though.
>
>
>I'm sure that if certification were suitable and appropriate facilities
>were widespread, there'd be a few executive DC-1s bought.  The Saudi
>royal family would surely buy one.  And then there's Air Force One...
>--

If the President used one,  then you'd have to buy at least 4-5.
first there is the dual backup, so no terrorist knows which one he is in.
then the secret service would want one or two to fly escorrt, rigged out
with weapons, in case of alien hijackers.  plus the press would need one.

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

Date: Fri, 11 Dec 92 15:49:08 GMT
From: Dave Jones <[e-mail]>
Subject: Cassini Undergoes Intensive Design Review
Newsgroups: sci.space

Hayim Hendeles ([e-mail]) wrote:
> In article <[e-mail]> [e-mail] writes:
> > ...
> >     After flybys of Venus (twice), Earth and Jupiter as it loops
> >around the sun to pick up energy, Cassini will arrive at Saturn
> >in November 2004, beginning a four-year orbital tour of the
> >ringed planet and its 18 moons. The Huygens probe will descend to
> >the surface of Titan in June 2005.
>
> Pardon my asking an ignorant question, but I can't understand why it
> should take 7 years to get to Saturn. When Voyager went to Jupiter and
> Saturn, it took (if I recall correctly) 4 years and a Jupiter flyby to
> make it to Saturn. Here, you are using 4 flybys, and it's taking you 7
> years! I would think that if you were to adjust the launch date so that
> Jupiter and Saturn were in the same relative positions as they were in
> 1977 (when Voyager was launched), you could do the same trick again (in
> the same 4 years).
>
Partly its the type of orbit used.  If you were to rendezvous with, say,
Mars, you'd use a minimum energy transfer orbit that would bring you to
Martian orbit with minimum velocity to kill in order to get into orbit
around the planet.  In contrast, if you just want to fly right by you can
travel faster.  When you design a fly-by mission you trade off the projected
lifetime of the probe (which translates to power generation capacity and
hence mass) rocket capability, number of instruments you want to
send, and how long you're prepared to wait to get your results.

In a rendezvous mission you're much more constrained by orbital mechanics.
Transfer orbits take a certain amount of time and there's not much you can
do about it.  All the dancing around in the inner system is designed to
get the probe into the transfer orbit in the first place.  The probes are
more massive than Voyager et al, since they carry more instruments,
secondary probes and, of course, rockets intended to put them into orbit
at their destination.  Getting them on track requires the dance, or
a hefty launcher.

This isn't to say that Galileo, for one, could not have gotten to Jupiter
faster.  What with politics, money and various disasters it didn't get the
launcher it was supposed to go up on.  After this last flyby it's just about
in the situation it would have been in had the right launcher been provided
in the first place.

Cassini's projected dance has to do with the problem of getting all that
gold plate up to speed......

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

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

Date: 11 Dec 92 17:10:55 GMT
From: Gary Coffman <ke4zv!gary>
Subject: DoD launcher use
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>
>The USAF Space Command is being briefed on DC and they are very interested.
>The current head of Space Command ran the air war against Iraq and was
>hampered by lack of access to satellite images. A vehicle with DC's
>turnaround time is just what he needs.

This puzzles me somewhat. DC would allow a short notice launch of a LEO
satellite, but such satellites have very short, and fixed, looks at a
given combat theatre. If would seem to me that recon aircraft are still
a better choice for tactical recon. Outside of the former SU there isn't
any system with a good chance of downing an SR71 28 years after it was
first fielded. In a situation like the Gulf War where US forces totally
dominated the air, it would seem that many types of photorecon aircraft
could deliver the needed pictures at any arbitrary time of any arbitrary
bit of terrain that needed a look see. Using DC itself as a recon platform
seems like serious overkill, but then the military always likes overkill
I suppose. I'd suspect that DC would be much more suited to being an
ASAT weapons platform than a spy carrier.

>Equally important, DC is a real kick-the-tires kind of vehicle which
>has appeal for the ex-fighter types who run the Air Force.

This sounds a lot more like the real reason.

Gary

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

Date: Fri, 11 Dec 1992 16:03:04 GMT
From: [e-mail]
Subject: Hubble's view of the universe
Newsgroups: sci.space,sci.astro

>
>>     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.
>
> I don't want to offend anyone, but this is simply not true....
> Ground-based telescopes (CFHT) can routinely acheive resolution (seeing) of
> 0.4 arcsec. Keck should be able to go deeper than HST ...

HST _currently_ has a highly stable and computable point-spread-function with
a sharp inner core 0.1 arcsecond in diameter, with the peak intensity confined
to a single pixel of the Planetary Camera (0.04 arcsecond).  The effect of
the spherical aberration is essentially to waste light, putting most of the
light in a much larger cob-web pattern.  The effect of the WFPC2 and COSTAR
corrective optics will be to put that wasted light back into the central
core.  I would be delighted to hear that any ground-based telescope can do
that routinely for faint objects, but it remains to be demonstrated.

Of course if you simply want to DETECT very faint objects in the 0.5 to 1.0
arcsecond range like very distant galaxies, a large ground-based telescope
has the advantage.

But still there are advantages in having an ultra-smooth mirror in space.  We
have a program to get reflection spectra of satellites of Mars next month.
Many good people have tried to do that groundbased, with the best equipment
at the best sites, but the atmospheric scattering of light from Mars always
makes a hash of the data.  For HST that problem goes away.

Ben

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

Date: 12 Dec 92 05:06:26 GMT
From: Ron Baalke <[e-mail]>
Subject: Magellan Update - 12/11/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Doug Griffith, Magellan Project Manager

                          MAGELLAN STATUS REPORT
                            December 11, 1992

1.    Magellan continues to operate normally, transmitting a carrier plus
40 bps X-band signal which is precisely tracked by the DSN (Deep Space Network
stations to provide gravity data.

2.    The present command sequence is designed to automatically shift the
telemetry to the 1200 bps rate if the tracking pass is over a 70 m
station, based on the DSN station allocation schedule as of the time
the reference file was prepared.  In the event the station assignment
is changed, some telemetry may be lost because the 34 m stations
cannot successfully receive the 1200 bps rate due to the Transmitter B
noise spur.

3.    Spacecraft temperatures remain in the expected range.  Bay 7, which
contains the CDS (Command Data Subsystem), is at 51 degrees C with a cycle
depth of 65 degrees.

4.    The spacecraft has completed 6294 orbits of Venus; 658 so far in
Cycle 4, which will end on May 25, 1993.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     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: 12 Dec 92 01:53:38 GMT
From: Ron Baalke <[e-mail]>
Subject: Mariner 2 Radiation Experiments - 12/28/62
Newsgroups: sci.space,sci.astro,alt.sci.planetary

OFFICE OF PUBLIC EDUCATION AND INFORMATION
CALIFORNIA INSTITUTE OF TECHNOLOGY
JET PROPULSION LABORATORY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.

FOR RELEASE:  P.M.'s of Friday, December 28, 1962
                  MARINER RADIATION EXPERIMENTS

          Mariner II carried two experiments designed to measure
the charged-particle radiation in space, including galactic
cosmic rays and streams of high-energy particles which are
released intermittently from the sun.  Virtually continuous
measurements of the particle fluxes in space were made by the
instruments throughout the 109-day journey to Venus and during
the passage near the planet on December 14, and additional data
have been received for approximately 10 hours per day since that
time.
          One experiment, for observing the higher-energy
particles (protons above 10 million electron volts (Mev) and
electrons above 0.5 Mev in energy) was designed by Dr. H. R.
Anderson of the Jet Propulsion Laboratory and Dr. H. V. Neher of
the California Institute of Technology.  Somewhat lower-energy
particles (protons above 0.5 Mev or electrons above 0.04 Mev) are
detected by the experiment of L. A. Frank and Dr. J. A. Van Allen
of the State University of Iowa.  Preliminary results of the two
experiments were reported at the Stanford meeting by Dr. Anderson
and Frank, respectively.
          The instrumentation for the high-energy experiment
consisted of a large spherical ionization chamber and two matched
Geiger counters.  The ionization chamber, which was invented by
Dr. Neher, has been widely used by him and by other investigators
for several years as a standard instrument for surveying the
absolute intensity of the cosmic rays.
          In addition to its use in almost countless balloon
flights, airplane flights, and ground-based experiments, this
type of chamber was also carried on the earth satellite Explorer
VI and on this country's only previous successful interplanetary
probe, Pioneer V.  The two Geiger counters are matched to count
the same kind of particles which are registered by the ionization
chamber.
          The detector for the lower-energy particles is a
cigarette-sized Geiger counter, the Anton 213, which was used in
several of the early Explorer and Pioneer satellites for
investigating the Van Allen radiation belts around the earth and
also in numerous more recent satellites.
          These experiments have three principal scientific
objectives, all of which were reported on at the Stanford meeting.
          Objective 1:  To detect, if possible, the presence of
magnetically-trapped particle belts about Venus.  For this
purpose, the Anton 213 counter was the most sensitive indicator.
At 20,000 miles from the earth it is known to have a counting
rate of several thousand per second, but during the closest
approach to Venus it detected an average count of only one
particle per second, in agreement with the rate observed during
most of the month of November.
          The absence of additional particles near the planet was
confirmed also by the other radiation detectors.  Near the earth,
the number of trapped particles observed decreases very sharply
with distance near the boundary between the earth's magnetic
field and the interplanetary field.
          Thus the absence of particles near Venus indicates that
the planet's magnetic field does not extend as far out as the
trajectory of Mariner.  This fact was confirmed by the magneto-
meter on board.  The small intensity and extent of the field is
believed to be explained by the very slow rate of rotation of the
planet.
          Objective 2:  To measure the intensity of the galactic
cosmic rays far away from the perturbing effect of any planet,
and to look for variations in this intensity in different parts
of the solar system.  Years of earth-based research have shown
that the flux of relatively low-energy galactic cosmic rays (5000
Mev and below) have a systematic variation with a period of about
eleven years which is somehow connected with the solar activity
cycle (sunspot cycle).
          It is hoped that cosmic-ray measurements made simultane-
ously in widely separated parts of the solar system will elucidate
the nature of the mechanism responsible for this variation.  For
this purpose, the ionization chamber is best suited.  It measured
a rate of ionization near 670 ion pairs per cubic centimeter per
atmosphere of air.  The value did not change significantly during
the flight, and furthermore is in agreement with measurements in
high-altitude balloons made last summer at Thule, Greenland, by
Dr. Neher.
          The Geiger counter on Mariner indicated a cosmic-ray
flux of approximately 3.0 particles per square centimeter per
second throughout the flight.  The constancy of the cosmic-ray
intensity over the very great distance traveled by Mariner is a
new and significant piece of information, but its real meaning
will not become clear until we have repeated the experiment
several times on space vehicles going out away from the sun as
well as in toward it.
          Objective 3:  To study the number and the nature of the
high-energy changed particles emitted by the sun.  (Another
Mariner experiment investigated the very low-energy solar
particles also.)
          The presence of these particles is indicated by sudden
increases above the cosmic-ray background reading of the various
particle detectors.  Some idea of their composition can be
obtained from a comparison of the response of different detectors.
The Mariner results were that high-energy solar particles, such
as could be detected by the JPL-Caltech experiment, were generally
absent except for a single event which began on October 23.  The
Iowa counter, on the other hand, detected not only this event but
at least eight others, which must therefore have been produced by
radiation or particles of very low penetrating power.  Its exact
nature is still in doubt at this time.
          The nature of the solar-particle event of October 23
was described in detail by Dr. Anderson.  A solar flare of a type
which has frequently produced streams of charged particles was
observed between 9:42 A.M. and 10:45 A.M., and the reading of the
ionization chamber began to increase even before the flare had
disappeared.  Its reading rose rapidly from a background of 670
to a peak of above 18,000, underwent several oscillations, and

remained above 10,000 for about six hours before declining
gradually over the next few days.  The flux of particles detected
by the Geiger counters rose from a background of 3 to a peak of
16 particles per square centimeter per second.  The fact that the
ionization increased much more than did the number of particles
indicates that the solar particles had much lower average energies
than the galactic cosmic rays, and it is calculated that a typical
energy in this event was about 25 Mev.  The details of the time
and energy variations will be further studied in the hope of
learning more about how the particles were produced in the photo-
sphere of the sun and how they may have been trapped in the
magnetic fields around the sun before being released to the region
where Mariner was waiting to detect them.
          The problem of solar flares and their production of
high-energy charged particles is a particularly important one for
interplanetary space research because the very largest solar
particle streams may contain particles in such numbers and of such
high energies as to constitute a significant hazard to manned
space missions.  No such events have been observed by Mariner,
however.
          The total radiation dose seen by the ionization chamber
in the October 23 event was only about 0.24 roentgen inside its
0.01-inch thick steel wall, and the radiation was so non-penetrat-
ing that a moderate increase in the wall thickness would have
excluded the particles almost entirely. For comparison, the radia-
tion dose recorded during the entire flight to Venus was about 3
roentgens, and much of this radiation was etremely penetrating.

225-12/62
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     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: 12 Dec 92 02:59:27 GMT
From: Ron Baalke <[e-mail]>
Subject: Mars Observer Update - 12/11/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE [phone]

                  MARS OBSERVER MISSION STATUS
                        December 11, 1992

     All spacecraft subsystems are performing well.

     The radio science flight sequence is winding down and
scheduled for completion on Dec. 14, 1992.  The next flight
sequence will prepare the spacecraft for its transition to the
outer cruise flight mode in which the high-gain antenna rather
than the low-gain antenna will be used.  The outer cruise
attitude transition begins on Dec. 15, 1992.  The Mars Observer
camera "bakeout" to prepare the instrument for operation will
continue in this next sequence through Dec. 28, 1992.

     A science experiment to observe Earth's geotail at a greater
distance than has been performed by other spacecraft started on
Dec. 9, 1992.  The geotail is the region of space in which the
solar wind is disturbed as Earth moves in its orbit around the
sun.  The experiment will use Mars Observer's magnetometer and
electron reflectometer to gather data on solar and magnetic
particle disruption in this region.

     Star-ephemiris tables, uploaded about once a week, continue
to adjust the spacecraft's solar panels so that they are
beginning to point more directly at the sun and the high-gain
antenna is pointing more directly at Earth.  These adjustments
are planned to continue through Jan. 2, 1993, when the high-gain
antenna is pointing directly at Earth.

     Today the spacecraft is about 25 million kilometers (16
million miles) from Earth, traveling at a speed of about 23,500
kilometers per hour (15,000 miles per hour) relative to Earth.
The spacecraft is traveling at a heliocentric velocity of about
105,000 kilometers per hour (66,000 miles per hour).

                             #####
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     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: 11 Dec 92 15:18:55 GMT
From: Bob McGwier <harder!n4hy>
Subject: Orbit Question?
Newsgroups: sci.space

>How about this.
>At the North pole,  the lines of force are headed almost straight down
>and beaucoup  charged particles are spiraling down.

The magnetic poles are NOT coincident with the rotational poles.

BMc

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

Date: 11 Dec 92 19:18:30 GMT
From: Pat <[e-mail]>
Subject: Scud Missile technology
Newsgroups: sci.space

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

Only a college boy would make this claim.
after all the appollos were programmed through panel switching at points.
B-52's were programmed by giant 16 position switches.
Paper tape is a reasonable solution considering the age of the missille,
the operating environment and relatively small data input.

i am sure the scud does not need to much data input other then a vector and range.

paper tape readers are also not dust sensitive or humidity sensitive.
i dont think any other media would have worked well given the 60's
era technology.

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

Date: 11 Dec 92 17:44:05 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Soaring like and Eagle (was Re: Range Safety and DC-X)
Newsgroups: sci.space

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

>>Oh, I don't know, Gary.  The thrust-to-weight ratio on DC-X probably
>>compares favorably with an F-15 Eagle...

>Yeah, but an Eagle has "wangs" (such as they are). :-)

And if the engines cut out during a trans-Atlantic flight, those
wings are going to do him a lot of good, aren't they?

Of course, wings can also fail.  You haven't actually proved
the chances of several engines failing simultaneously on a VTOL
are any greater than the chances of a HTOL's wings falling off
(or, more likely, control surfaces jamming or hitting a bird
during that long, gliding landing).  You've asserted it, but
you haven't proven it.



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

Date: 11 Dec 92 17:30:29 GMT
From: Henry Spencer <[e-mail]>
Subject: spaceships as missiles
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (forrest.e.gehrke) writes:
>>... 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.)
>
>You mean (Gasp!) Senator Nunn will have to give up and agree to
>ending the Anti-missile Treaty?

Well, if not, I guess the US and Russia will just have to remain defenceless
while the rest of us do something about it. :-)

Sort of seems appropriate, somehow, considering what you've put the rest of
us through over the last few decades. :-) :-) :-)
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 11 Dec 92 17:57:19 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:
>
>>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.

Snide remarks not withstanding, chamber pressure isn't the only form
of stress on a vehicle. While I like Truax's Sea Dragon proposal
on several grounds, the low chamber pressures lead to very high
loads on the turbopumps because so much more fuel per unit time
has to flow to achieve the high thrust required with low pressure
engines. Reducing stress in one area can lead to increased stress
in another area when the objective remains to get a vehicle from
surface to orbit in a single leap. The high speed pumps, not combustion
chamber stresses, are the main reliability concern of liquid fuel rockets
anyway.

>>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.

I'm not convinced this is true, especially if most of the "wing" is really
lifting body. Also the fuel is not the only mass penalty of VTOL, bigger
tankage and structure are required as well. Certainly I agree that HTHL
is most efficient since you don't need as much fuel to get to orbit, or
to get landing fuel to orbit when aerodynamic lift can help out. That
means your vehicle can be smaller and have a better mass ratio than the
pure brute force approaches. Certainly a launcher that is never intended
to re-enter the atmosphere is more efficient without wings, but if the
wings can handle the bulk of the return trip as passive systems not
requiring high speed high precision machinery, they deserve serious
consideration.

Gary

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

Date: 12 Dec 92 01:57:36 GMT
From: Ron Baalke <[e-mail]>
Subject: Ulysses Update - 12/11/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE [phone]

                     ULYSSES MISSION STATUS
                        December 11, 1992

     All spacecraft and science operations are performing well.
Routine Earth-pointing maneuvers continue to be conducted about
every five days.  The last maneuver was performed on Dec. 9 and
the next is scheduled for Dec. 14.

     Ulysses' on-board tape recorders will be switched tomorrow,
Dec. 12.  Tape recorder 2 will become the primary recorder and
tape recorder 1 will be used as a backup unit.

     A reduction in the number of ranging passes continued during
this reporting period to improve the spacecraft signal at its
great distance from Earth.  Today Ulysses is about 760 million
kilometers (470 million miles) from Earth, traveling at a
heliocentric velocity of about 32,500 kilometers per hour (20,600
miles per hour).  The spacecraft is 14.3 degrees south of the
ecliptic plane in which the planets orbit, slowly looping its way
back toward the sun.

     The Keppler Gas Experiment that measures neutral helium gas
from interstellar space was turned on again on Dec. 9.
Measurement of the arrival speed and direction of the
interstellar gas allows scientists to determine how our solar
system is moving through interstellar space.  Now that Ulysses
has climbed more than 14 degrees out of the ecliptic plane, it is
possible to determine speed and direction more accurately by
including measurements made in the third dimension.

                            #####
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     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: 11 Dec 92 17:52:49 GMT
From: "Patrick C. Mock" <[e-mail]>
Subject: What is a VSAT?
Newsgroups: sci.space,sci.astro

Does anyone know what does VSAT (Very Small Aperature Terminal) mean
in the context of satellite communications?

Thanks
Pat

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

Date: 11 Dec 92 19:38:26 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: what the little bird told Henry
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:

>I'd be curious to know the exact date, sometime in the last 20 years,
>when "success oriented" became a pejorative phrase.

I was thinking about that recently. My conclusion was that it was around
the time MacManera (I know that's spelled wrong) became Sec. of Defense.
He put in a bunch of the changes which makes it so hard to get things done.

Without researching it much, it seems to me that the time it took USAF to
build and deploy a new aircraft roughly doubled when he took over. Ditto
for price.

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------134 DAYS TO FIRST FLIGHT OF DCX----------------------+

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End of Space Digest Volume 15 : Issue 537
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