Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V15_0/V15NO045.ZIP/V15NO045

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Date: Wed, 29 Jul 92 05:00:04
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #045
To: Space Digest Readers
Precedence: bulk


Space Digest                Wed, 29 Jul 92       Volume 15 : Issue 045

Today's Topics:
                Antimatter (was propulsion questions)
                         Calendar and Zodiac
                        Clinton Space Position
                              Decisions
                                Delta
                     Early Robotic Lunar Missions
                        ETs and Radio (2 msgs)
      Inverse Ephemeris (time as a function of position) Wanted
      Russian/French Soyuz TM-15 mission launched to Mir station

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

Date: Tue, 28 Jul 92 13:38:12 EST
From: [e-mail]
Subject: Antimatter (was propulsion questions)

It seems that antiprotons can live inside matter far longer than was
initially thought. In 1947, Fermi and Teller calculated a 10^-13 seconde
value ( 0.1 picosecond). But from bubble chambers experiments with
negative pions and kaons, it was inferred that the real time could be
100 picoseconds. Now, first at the KEK Japanese laboratory, and then
at CERN, it has been shown that, inside helium at 6 atm. pressure,
4% of the antiprotons live several microseconds. If the helium is
"contaminated" with a small amount of hydrogen (0.04 %) this time is
divided by about 10. Many questions remain, in particular is this a
specific property of helium.

J. Pharabod

Reference:"Antiprotons refractaires a l'annihilation", Courrier CERN,
June 1992.

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

Date: 28 Jul 92 12:06:03 GMT
From: John Roberts <[e-mail]>
Subject: Calendar and Zodiac
Newsgroups: sci.space

-From: [e-mail] (Richard Ottolini)
-Subject: Re: Calendar and Zodiak
-Date: 27 Jul 92 22:07:16 GMT
-Organization: Unocal Corporation

-No, the calendar stays the same, but the sky changes.
-The yearly calendar until @1950 was defined as the time between extremal
-positions of the sun: furthest north or south of the year etc.
-However, the position of sun with respect to the stars at the extremal point
-moves slightly each year- about the diameter of the moon per 36 years.
-The vernal equinox (spring) now occurs when the Sun is in the constellation
-Aquarius.  During the Roman Empire the sun was one constallation over in Pisces
-during the equinox.
-After 1950 the length of the year is defined in terms of vibrations of cesium
-atoms which are ten million times more stable than the length of a year.

Thanks for the explanation. I would like to add a refinement: It's the
*second* which is defined by atomic vibrations - larger units of time are
roughly defined by number of seconds, but the passage of the larger units of
time is still subject to celestial motions. You can't say "there are x seconds
in a year, so the instant corresponding to this one 100 years ago was
exactly 100x seconds ago". The Naval Observatory keeps track of the passage
of the sun (and possibly the stars - I'm not sure), so there's no ongoing shift
between local solar noon and noon by the clock. Since the Earth's rate of
rotation is not constant, the clock time has to be adjusted every now and then.
The year is *probably* defined by the background of distant stars, at least
in the long run.

John Roberts
[e-mail]

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

Date: 28 Jul 92 14:36:54 GMT
From: Doug Davey <[e-mail]>
Subject: Clinton Space Position
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> In article <[e-mail]> [e-mail] (Robert Bunge) writes:
> >administrations have failed to establish priorities, and because
> >they have not matched program needs with available resources, NASA
> >has been saddled with more missions than it can successfully
> >accomplish.
>
> Translation:  we're going to kill some of the NASA programs, although
> of course we're not going to tell you which ones.

[ Several more "translations" deleted. ]

> --
> There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
> mistakes, but... make *new* ones. -D.Sim|  [e-mail]  utzoo!henry

Henry, your technical postings are probably the best things in sci.space.*.
However, I would respectfully ask that those who neither pay the taxes
nor vote in the elections kindly refrain from posting politcal analyses
of political statements from the USAian election campaign.  If you have a
technical reason why something a candidate proposes is a good or bad idea,
fine.  However, a cross border political analysis is rude at best.  Thanks.
Stop Canadian Imperialism!  Yankee Go Home! :-)

--
+--------------------------------------------------------------------+
  Doug Davey        [e-mail]         bcr!iscp!ddavey

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

Date: 28 Jul 92 12:19:04 GMT
From: John Roberts <[e-mail]>
Subject: Decisions
Newsgroups: sci.space

-From: [e-mail] (Graham Flower)
-Subject: Stellar Structure References
-Date: 27 Jul 92 23:55:18 GMT
-Organization: the HP Corporate notes server

-...

-Graham Flower ms 90-TT               |  Better to have convictions and act on
-Hewlett-Packard  350 W Trimble Rd    |  them, even if they are wrong, than to
-Microwave Semiconductor Division     |  waffle in indecision.

I don't agree with that as a general rule for living. You have to weigh the
expected cost of making the wrong decision against the opportunity cost of
postponing the decision. Often the reason for indecision is lack of adequate
information to make a good decision, and often this problem can be remedied
if you wait until better information is available. Sometimes an entirely new
option becomes available, that is better than any of the previous choices.
It really has to be judged on a case-by-case basis.

John Roberts
[e-mail]

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

Date: Tue, 28 Jul 1992 00:25:00 GMT
From: [e-mail]
Subject: Delta
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (George William Herbert) writes...
>In article <[e-mail]> [e-mail] (John Roberts) writes:
>>[...]
>>There have been proposals for a heavylift Delta, which as I gather is
>>essentially a whole batch of Delta rockets (complete with boosters)
>>strapped together.
>>[...]
>
>    The HL Delta design doesn't use solid boosters on all the
>"core" vehicles... the one I saw had 24 Castors, four per on the
>six outer Delta vehicles.  The problem that you pointed out [deleted from
>included text] with staging solid boosters from the "inside" of the
>cluster is avoided by not putting any inside 8-)
>    The HL Delta is a neat vehicle concept... it does as reported
>here have a safety margin in excess of 2.0 in all of the new hardware,
>because the designer didn't want to spend $5 billion dollars and five
>years to qualify it.  He was figuring an order of magnitude
>less expensive and eighteen months.  Probably optimistically,
>but nonethelessvery reasonable. 8-)  I had a chance to talk to
>him for a while ... he knew it could be done quick and dirty and wanted
>to do it that way, dammit. 8-)  [name escapes me entirely, and I may
>not have written it down... sorry].
>
>-george william herbert
>[e-mail]
>
>

You know what's funny here is that this idea was tried successfully about
thirty years ago. The boosters that were paralled together were Redstones, and
the vehicle produced was the Saturn I and IB. Very successful rockets, 28
launches and *NO* failures.

Dennis, University of Alabama in Huntsville

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

Date: 28 Jul 92 14:03:06 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Early Robotic Lunar Missions
Newsgroups: sci.space

[Remember I was complaining about the dearth of information on the
NASA Office of Exploration lunar missions?  Here's my contribution to
filling the gap. Reprinted with permission from *Lunar and Planetary
Information Bulletin* No. 63, May, 1992. --WSH]

         BACK TO THE MOON -- EARLY ROBOTIC MISSIONS

by David C. Black and Paul D. Spudis

NASA's newly re-established Office of Exploration is planning several
small, robotic missions to the Moon within the next three years to
begin the Space Exploration Initiative, the nation's program
to return to the  Moon and journey to Mars. The need for
small, unmanned lunar missions is both technical and
programmatic. To support extended human operations on and
around the Moon we must acquire knowledge about the distribution of
lunar resources and the detailed characteristics of the surface at
proposed  human outpost sites, and we must learn more about the
gravity field and  global terrain. For the program to succeed,
we must demonstrate that innovative, inexpensive
exploration techniques are feasible and will   produce
quality results.

  A Workshop on Early Robotic Missions to the Moon was held at the
Lunar and Planetary Institute, February 4-6, 1992, to assess instruments
that could be used on these early unmanned missions. Instruments
were evaluated mainly for scientific relevance and quality of the
dataset that they would return; however, their usefulness in resource
exploration and processing was also considered.

  The Office of Exploration has established four themes for early lunar
robotic missions: resources, terrain--both topography (altimetry) and
surface morphology (imaging)--gravity, and lander missions.

ORBITAL AND LANDED PAYLOADS

Sixty instrument or mission concept proposals, about equally divided
between orbital and landed operation, were considered.

  The Lunar Exploration Science Working Group (LEXSWG), a standing advisory
group to the Solar System Exploration Division of NASA's Office of Science
and Applications (OSSA), has developed a prioritized list of global data
sets with specific quantitative measurement requirements that are desired
from lunar orbital missions (see table). The workshop found that there are
excellent candidate instruments to obtain these datasets. At present, there
is no prioritized list of data sets expected from payloads landed on the
lunar surface (although one is being developed by the LEXSWG).

   We discussed landed payloads in the context of the proposed "common
lunar lander," Artemis. Payload capability would be only about 65 kg for
the first lander, but most proposals anticipate a 200-kg capability, which
is being investigated for subsequent versions of Artemis. Also, the
baseline design of Artemis has no provisions for power or communications.
These engineering constraints did not affect the workshop's assessment of
the various landed instruments.

   While landed payloads in general are not as fully developed as orbital
payloads, a wide and interesting range of concepts offers great scientific
potential as well as being useful for exploring lunar resources.

RECOMMENDATIONS

We concluded that these missions offer the opportunity to do outstanding
science, and that there are high-quality instruments that could be flown
within three years, including landed science as well as orbital science
instruments.

  Flight-ready, new-generation instruments are, in general, not immediately
available, and some of the more promising instruments that were reviewed,
while not new in concept, are still at the advanced testing and breadboard
stages. This is because relatively little lunar instrument development has
been done during the past decade and a half, so most of the state-of-the-
art instruments reviewed at the workshop were developed for nonlunar
missions, or their components have been qualified for spaceflight in other
contexts. The suite of instruments that we recommend can be flown within
three years, as long as prompt and adequate funding is made available to
the instrument teams. The Office of Exploration should take the lead in
establishing a flight instrument development program.

  This instrument situation applies not only to the science payloads, but
to the resource-utilization payloads that were reviewed at the workshop.
The maturity of the proposed resource utilization concepts, potentially
quite useful to achieving the goal of a permanent human presence, is not as
advanced as those for many of the science instruments; few have even
breadboard hardware models. As with science instruments, there is a
critical need for NASA to initiate resource instrument development.
Resource utilization instruments could be flown soon after more mature
science instruments, provided that development starts soon.

  The workshop also noted a pressing requirement for mobility on early
landed science missions and that the JPL minirover is relatively mature and
addresses most mobility needs for early exploration. The Office of
Exploration should examine whether other engineering solutions could be
developed quickly enough.

Orbital Mission 1  Resources

Three proposed instruments working together can provide global maps of
lunar chemistry and mineralogy. We believe that given adequate and timely
resources, flight-ready versions of these instruments can meet a launch
date within three years. Their combined mass, power, and datarates are
plausible for orbiters of modest capacity.

  A gamma ray/neutron spectrometer with a germanium detector would provide
global chemistry with a low resolution footprint (dependent on orbital
altitude, but greater than 100 km). This is the only instrument that senses
composition to depths greater than several micrometers. The scientific
return is very high, but cooling the detector to 70 K poses a challenge.
Should this preclude a 1995 launch, a similar instrument using a sodium
iodide detector could provide useful preliminary information until the Ge
detector is launched later.

  A soft X-ray fluorescence instrument, to be flown soon on the Alexis
spacecraft, can detect all major elements with high spatial resolution (1-
km pixels) to yield far more definitive constraints about regolith
characteristics, origin, and evolution than was thought possible from an
orbital mission until very recently.

  A visible-infrared reflectance instrument provides information on
minerals in surface soils. A full-scale imaging spectrometer collects image
data in hundreds of spectral channels; thus, each pixel has a single
spectrum of up to 256 points. If this instrument is not ready for flight in
three years, a capable multispectral imager (of about six channels) could
be sent on an early lunar mission. One of these instruments should be part
of the first suite of instruments; the choice between them is a matter of
technical readiness. The full-scale imaging spectrometer should be flown as
early as possible.

Orbital Mission 2  Terrain

From the Apollo program, we already have some maps of the topography and
gravity field of the Moon. However, serious gaps exist in these data in
both in coverage and quality. Instruments for a second orbiter should
obtain global gravity and terrain information to support exploration and
scientific studies.

  A laser altimeter can collect global altimetry giving us an accurate
picture of the lunar figure and gross topography of large regions. A number
of the proposed altimeters have some flight hardware derived from the Mars
Observer program. Which one to select is purely an engineering issue, as
long as the instrument meets the LEXSWG requirements (Table 1).

  Mapping variations in the gravity field on both the nearside and farside
is important for operations in lunar orbit and to understand the internal
composition and state of the Moon. Because global coverage is considered
essential, two spacecraft are necessary to determine the gravity field (the
nearside can be done with one); the second spacecraft is an extremely
inexpensive "subsatellite" deployed directly from the main orbiter. The
most rapid characterization of the global field would be achieved by a
concept in which a passive laser reflector co-orbits with the main orbiter
at a relatively low altitude. Instrument readiness will determine which
technique is selected.

  Coupling imaging with altimetry and gravity will achieve excellent
science return as well as operational information that would be of longterm
use to the Exploration Initiative. The imaging system should be capable of
taking stereo imaging data at a ground resolution of 15 m/pixel; a
highresolution mode (2 m/pixel) would permit detailed study of specific
sites for landed missions, either human or robotic. This global
cartographic database will serve exploration needs in both science and
operations. Several imaging systems were considered: All would provide
quality data and all have some flight hardware available.

Lander Mission  Surface Rover(s)

Although landed payload instruments are not as highly developed, a capable
suite of instruments can be available to fly on the prototype Artemis
lander.

  After considering several possibilities, the workshop concluded that a
surface rover mission is a logical candidate for the first Artemis mission.
JPL has been designing and fabricating test rovers for several years,
including a set of minirovers, two of which could fit within the 65-kg
payload of the first Artemis mission.

  Several instruments could be mounted on such a rover to characterize in
some detail the compositional and physical properties of a potential lunar
outpost site. This mission could be either the prelude to more extensive
surface investigation (by robotic or human missions) or a onetime
exploration of a scientifically interesting or operationally challenging
site.

  An alpha-proton backscatter spectrometer would provide important
information on the chemical composition of lunar soils. A Mossbauer
backscatter spectrometer would complement the alphaproton instrument and
provide highquality mineralogical data in addition to measurements of soil
maturity. Stereo, highresolution cameras would document compositional
analyses, permit physical characterization of the site, and allow all of us
on Earth to share the excitement of the first return to the Moon.

  These instruments are a minimum to return excellent scientific and
resource characterization data. Other instruments, in particular an evolved
gas analyzer to measure in situ concentrations of solar wind hydrogen,
should be added to the rover payload as resources permit.

CONCLUSIONS

Not only were logical collections of instruments identified to carry out
specific exploration themes, but we found that it's highly probable that
these instruments can be built, integrated onto a spacecraft bus, tested,
and launched within the 3-year schedule proposed by the Office of
Exploration. This is indeed a "faster, cheaper, better" way of  exploring
space. Scientists who attended strongly endorse this new approach and stand
ready to help the Office of Exploration carry out the Space Exploration
Initiative.

(Dr. Black is Director of LPI; Paul Spudis is a Staff Scientist
at LPI.)

LEXSWG Orbital Dataset Requirements for Global Measurements

Priority     Measurement               Requirement
   1         Elemental Composition.....<100-km resolution
                                       <20% precision
   2         Topography................<1-km resolution
                                       <+10-m vertical
             Gravity...................<100-km resolution
                                       +1 mgal
   3         Mineral Composition.......<500-m/pixel resolution
                                       +5% abundance
   4         Imaging...................15+5-m/pixel resolution
                                       100-300-m pos. accuracy
   5         Magnetic..................<30-km resolution
                                       +0.1-nT precision
   6         Atmosphere................Species present, state
                                       <100-km resolution
                                       +10% precision
   7         Surface thermal...........<100-km resolution
                                       0.5 degrees K (+4 mW/m^2)

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

Date: 28 Jul 92 10:57:43 GMT
From: James Annis <[e-mail]>
Subject: ETs and Radio
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Derek Wee) writes:
>
>Anyone have any good arguments FOR the existence of extraterrestrial
>intelligence?
>
           11                 9
sure:    with 10   stars in our galaxy, 10  galaxies in the observable
    universe, the odds of us being unique start at
      20
    10  to 1 against.

--

James Annis               [e-mail]

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

Date: 28 Jul 92 13:02:36 GMT
From: russell wallace <[e-mail]>
Subject: ETs and Radio
Newsgroups: sci.space

Given that for evolution of life to start, a simple living organism must
come together from amino acids etc. by accident; and that for any
complex structure to fall together by accident is extremely improbable;
then it looks pretty much like the odds against life appearing on any
one planet could easily be more than 10^1000 to 1 against, and the
number of planets in the visible universe is only about 10^22.

--
"To summarize the summary of the summary: people are a problem"
Russell Wallace, Trinity College, Dublin
[e-mail]

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

Date: 28 Jul 92 12:01:34 GMT
From: Gary Murphy <[e-mail]>
Subject: Inverse Ephemeris (time as a function of position) Wanted
Newsgroups: sci.space,sci.astro

In article <[e-mail]> [e-mail] (Mike Melnyk) writes:

   I am in need of an inverse ephemeris for the sun. That is, I am
   looking for function that returns the time of year, given the position
   of the sun in geocentric ecliptic coordinates and a year of interest
   (e.g., 1994).

   This function only need be accurate to 1' from 1994 - 2000.

   Yes, yes, I know that I can use a true solar ephemeris (e.g.,
   Van Flandern and Pulkkinen's formulae) to iteratively solve for
   the time of year, but I'd rather not take the time to write and test
   the code if an inverse ephemeris exists.
   -------------------------------------------------------------------------
   Mike Melnyk                                         [e-mail]
   Infrared Processing and Analysis Center
   JPL/Caltech

Does this imply JPL is investigating Nostradamus? :-)

seriously (before wolf flames me for not being so ;-) ...

Elwood Downey's most excellent (and free) ephem program will do not only
this, but also return all those composite conjunctions and separations
which Michel d'Notradame was so fond of (if only he'd had a PC in 1557!)

I don't know where exactly to find them, but an archie server should be
asked to look for ephem (I think the current version is 4.13) or xephem
if you can compile for X11/Motif (I can't :-( )

I've posted this in addition to mailing it, just in case NASA and NRAO
are also looking into Nostradamus' Aug 12, 1999 predictions :-)

--
Gary Lawrence Murphy - [e-mail] - [phone] x3709
          In this very moment - what is there lacking? -- Hakuin

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

Date: Tue, 28 Jul 1992 00:10:28 GMT
From: Glenn Chapman <[e-mail]>
Subject: Russian/French Soyuz TM-15 mission launched to Mir station
Newsgroups: sci.space

     The Russian/French Soyuz TM-15 mission to the Mir space station was
launched today (July 27). Onboard this  flight were cosmonauts Anatoli
Solovyov and (Soyuz TM-5 to Mir June '88 for 9 days and Soyuz TM-9 to Mir in
Feb '90 for 180 days) Sergei Avdeyev (first mission) from CIS (Commonwealth
of Independent States) plus Frenchman Michel Tognini (also first flight).
The crew will dock with the Mir complex on July 29th to join cosmonauts
Alexander Viktorenko and Alexander Kaleri, who are in their 5th month in
space (since Mar. 17th).  This "Antares" mission was paid for by the French
and is devoted to life sciences/materials processing.  Equipment for the
flight was brought up on the Progress M-13 cargo craft which was launched on
June 30th and docked with Mir on July 4th, after an unsuccessful docking
attempt on July 2nd.  One interesting point is the duration, which was
originally set for 12 days, then increased to 16 days several months ago.
After this mornings launch the CBC reported it as a month long mission.
Viktorenko and Kaleri will return with Tognini in the Soyuz TM-14 craft.

    Solovyov and Avdeyev are scheduled to receive Progress M-14 on Aug. 14th
bringing up the 0.7 Tonne Sofora propulsion unit (VDU).  Solovyov and Avdeyev
will engage in four space walks to attached the Sofora to the 14 metre truss
built on the Kvant module by Arsebarski and Krikalev in July 1991.  The long
leaver arm of the truss will enable the Sofora rockets to control the
attitude of the Mir complex with considerably less fuel usage.  The heavy
attitude demands of Mir, with tis two 20 Tonne side modules, have put
excessive demands on the gyrodyne attitude controllers on the Kvant modules,
causing 5 of them to suffer damage. October will see Progress M-15 bring up a
test solar sail that will be deployed about Oct. 20th.

    The next mission is scheduled for November when cosmonauts Manakov and
Poleshchuk bring up an Israeli visitor on a commercial mission. Manakov and
Poleshchuk are training for the space walks to repair the gyrodynes, which
were never expected to be replaced in space. (Radio Moscow, CBC radio and
Spaceflight, July)

    Sorry that I have been off the net in reporting for a while.

                            Glenn Chapman
                                                        School Eng. Science
                            Simon Fraser U.
                                                        Burnaby, B.C., Canada
                            [e-mail]

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

End of Space Digest Volume 15 : Issue 045
------------------------------