Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_0/V12_022.TXT

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Date: Sat,  7 Jul 1990 01:33:44 -0400 (EDT)
Subject: SPACE Digest V12 #22

SPACE Digest                                      Volume 12 : Issue 22

Today's Topics:
                 Julian Date
                Units
           Re: grim tidings for the future
           Re: grim tidings for the future
               Usability of HST
           Re: grim tidings for the future
                  Re: Units
             Re: realities of testing HST
           Re: grim tidings for the future
              Re:  SPACE Digest V11 #592
              Re: Nasa's budget
            HST <-> Manned Shuttle

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription notices,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

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

Date: Fri, 6 Jul 90 01:44:22 EDT
From: [e-mail] (Keith F. Lynch)
To: [e-mail]
Subject: Julian Date
Cc: [e-mail], [e-mail]

> The problem is that for an image in 1986 and about the 178th day the
> time fields have a value such as 46605.98125432.  I don't know how
> to interpret this value.  Someone suggested that it is probably
> daynumber.partoftheday.

Right.  Julian date 2446605 was the 174th and 175th day of 1986 (June
23 and 24).  The number simply increases by one each day, at noon UT.
The evening of today, July 5th, day 186 of 1990, is 2448078.

They've lopped off the leading two digits to save space, since '46605
won't recur for over 270 years.

This system is often used by astronomers, since it allows the time
between to events to be calculated much more easily than with the
usual calendar.  The system itself was originated over 400 years ago.
The start date is the congruence of several arbitrary cycles that
seemed important at the time but are virtually forgotten today.
                                ...Keith

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

Date: Fri, 6 Jul 90 01:44:14 EDT
From: [e-mail] (Keith F. Lynch)
Subject: Units
Cc: [e-mail]

sun-barr!newstop!texsun!digi![e-mail]  (Marc Sissom) writes:
> Well, why not change the length of the second instead?  Now the
> second lasts about as long as it takes light to travel some 300,000
> km.  We really ought to set this up so that light travels maybe
> 100,000 or 1,000,000.

Well, we shouldn't call it a second, then, as that would lead to
confusion.

If you want to start a new system of units, why not set the speed of
light to 1?  That is, choose units of time and of distance such that
the speed of light has that value?  You might as well set Planck's
constant to 1 as well.  If you also set the gravitational constant to
1, all your units will then be defined - there's only one possible
system of units for which these all come out that way.

Quantities for commonplace things will tend to be very large or very
small, but at least the math will be a little simpler.

> Perhaps we should stop using a base ten numbering system, and count
> in binary!

Better yet, base e.  Then logarithms will come out better.

Good luck getting anyone else to adopt this system.
                                ...Keith

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

Date: 7 Jul 90 00:00:29 GMT
From: earthquake.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Re: grim tidings for the future

In article <[e-mail]> [e-mail] (Steve Emmerson) writes:
>
>According to the GAO (sorry, no references) direct investment by the
>Government was three times more efficacious in stimulating new technology
>than the indirect, "spinoff" effects of the Apollo program.

The arguement was that NASA is a bad investment.  It isn't.  There may
be better investments out there, but that's not the point.  Money
spent on space is _not_ wasted.

-george

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

Date: 7 Jul 90 03:57:38 GMT
From: dftsrv!nssdcb.gsfc.nasa.gov![e-mail]  (Lee Brotzman)
Subject: Re: grim tidings for the future

In article <[e-mail]>, [e-mail] (Jonathan Leech) writes...
>In article <[e-mail]> [e-mail] (Doug Mohney) writes:
>>In article <[e-mail]>, [e-mail] writes:
>>>
>>>Hmm, Voyager, Magellan, Galileo, Ulysses, IUE, IRAS, Pioneer-Venus, ICE,
>>>Astro, HEAO, SMM etc etc are not remnants of the 60s.  People like you
>>>are only looking at the flambouyant aspects, scientits look back and see
>>>an impressive array fo science in the last 15 years.
>>
>>Funny how all those projects were successful on economy budgets rather than
>>deluxe class "big science" tickets.
>
>    You think Galileo is on an economy budget?    Try again.
>--
>    Jon Leech ([e-mail])    __@/
   And lets not forget COBE and ROSAT.  Both of those babies are
returning plenty of good science.  I wonder if noone wants to mention
COBE simply because it is giving us the answers we _expected_ to get.
That instrument is performing flawlessly.  And we should remember that
it was completely reengineered so as to fly on a Delta instead of the
Shuttle.  The NASA design team worked their tits off to perform that
feat.
   I have some close personal knowledge of the people and procedures
that were needed to make the COBE project work.  Some of the ROSAT
scientists work next door to me and I have the highest respect for
them.  I think that some are to quick to criticize NASA's science
efforts when they have absolutely no knowledge of the hard work and
dedication that has been expended in these projects.
   Not all the dollars go to the "Big Science" projects.  NASA funds a
lot of little science projects as well, as any cursory glance in the
acknowledgments sections of scientific papers in the Astrophysical
Journal and Astronomy and Astrophysics would atest.  Let us remember
that real science is not reported in the newspapers.

-- Lee E. Brotzman                    Internet:  [e-mail]
-- Science Applications Research      SPAN:      NSSDCA::BROTZMAN
-- Astrophysics Data System           BITNET:    ZMLEB@SCFVM
-- National SpaceScience Data Center  "My thoughts are my own"

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

Date: 6 Jul 90 21:18:51 GMT
From: unmvax!ariel.unm.edu!hydra.unm.edu![e-mail]  (Eric Jaderlund)
Subject: Usability of HST


   Many people seem to be under the impression that Hubble will not be
able to do anything worthwile in it's present state.  It is true that much
of the bally-hood(sp?) imaging will not be possible until the next shuttle
visit but until then I am sure that it will be busy almost all the time.
Recall that the demand for HST observing time far outstripped the available
time, so only the science that was best accomplished with HST was scheduled.
Now that the capabilites have changed there will be a new emphisis on
different types of observations (UV imaging, for one) that will now receive
top priority.  Remember that the photometers and spectrometers (the prime
instruments of astronomy) should all work near to original designs.  The
cameras will probably do no better than those on the ground but will be able
to take picures in the UV which can't be done from Earth.

  As it turns out things could be a LOT worse.  Don't get me wrong, the
matter of the mis-made-mirror needs to be investigated closely.  It is
my humble opinion that the problem will be traced to poor communications
and/or management.  As I have said before, we should be thankful that all
the complicated devices seem to work just fine.  It's always the simple things
that get you.

-----------------------------------------------------------------------------
Eric Jaderlund                                 [e-mail]
University of New Mexico                       Disclaimer: "Nothing exists"
Dept. of Physics and Astronomy
-----------------------------------------------------------------------------

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

Date: 6 Jul 90 14:38:10 GMT
From: mojo![e-mail]  (Doug Mohney)
Subject: Re: grim tidings for the future

In article <[e-mail]>, [e-mail] writes:
>>>    You think Galileo is on an economy budget?    Try again.
>>
>> Compared to what? Hubble?
>
>Galileo is a $902 million project compared to HST's $1.5billion (+
>expenses down the road).  Magellan is $463 million and the gamma
>ray obs is $500 million.  Those aren't small potatoes!

So I can get 3 Magellans or three Gamma Ray Observatories for the price
of one Hubble? Or another Galileo and a Gamma Ray?

Maybe it's time to start rethinking our whole policy of space exploration.
Back in the "Old Days" we would build two or three of everything just in
case. Now, we come up with one and if it fails...

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

Date: 6 Jul 90 15:16:45 GMT
From: agate!shelby!med!hanauma![e-mail]  (Richard Ottolini)
Subject: Re: Units

In article <[e-mail]> [e-mail] (Keith F. Lynch) writes:
>sun-barr!newstop!texsun!digi![e-mail]  (Marc Sissom) writes:
>> Well, why not change the length of the second instead?  Now the
>> second lasts about as long as it takes light to travel some 300,000
>> km.  We really ought to set this up so that light travels maybe
>> 100,000 or 1,000,000.

Most base units were chosen commeasurate with human life.
Humans are within a factor of ten of a meter.
A second is a fraction of the day and a heartbeat.
Mass and temperature are related to water, the essence of life.

Second/years become obsolete once you step off planet earth.
I would chose something called Human-Planck units, defining unity as
the power-of-ten of Plank distance, Planck time, and Plank mass nearest
to the meter, kilogram, and second/year.
(The Planck units combine both the thought-to-be-invariants of the quantuum
of action and the speed of light.)

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

Date: 6 Jul 90 10:47:21 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: realities of testing HST

>>>"Can you please tell us why you awarded a contract for several hundred
>>>million dollars to a contractor that you now feel you cannot trust?"
>>
>>Trust but verify.
>
>"If you trust them, sir, why do you need to spend money verifying that
>they have done what you claim you trust them to do?"
>
>I understand the distinction; my point is that J. Worthless Congressthing
>doesn't.
>
>(As witness some of the imbecilic pronouncements now coming out of
>Congressthings on the subject of HST.)

There are several things wrong with this line of argument.

The distinction between trust and blind faith is common sense, which
(believe it or not) ain't that hard to come by in a Congressional
subcommittee meeting.  The arguments in favor of optical system testing
are very straightforward.  If you must have the above imaginary debate
in some chamber or other, there is no reason to be afraid of it.  If
NASA had had the guts - aka leadership - to try and get the test
budgeted, and it had somehow been denied, we would be no worse off than
we are now.  Indeed it would be more likely that someone on the
subcommittee would ask NASA to find a cheaper way to do it -- say, using
the military facilities NASA now claims it never knew about.  The Capitol
is full of people who work with military contractors and don't share the
agency's apparent reverence for their infallibility.

If there is specific evidence that Congress would not have approved
an integrated optical test, let us hear it.  Likewise, what *specific*
"imbecilic pronouncements" have Congresspeople made about HST?  I see
a lot of news pass across my desk; there has been plenty of anger, but
not much stupidity on this issue.

>And you'd better believe that on a program suffering from serious cost
>overruns in a time of very tight NASA budgets, NASA cared about that
>viewpoint.

I had better have evidence before I believe.  Did NASA really think that
an integrated optical test was necessary but that it was impossible to
ask for the money?  Everything we have heard so far indicates the
opposite, that NASA felt it was not worth the money because the
contractor could be relied to do the mirrors right.  This is one of the
most interesting questions the investigatory panel can answer.  It
will tell us *how* NASA mismanaged, not *whether*.
--
Perestroika: could   \O\     Tom Neff
 it happen here?      \O\    uunet.bfm.com!bfmny0!tneff

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

Date: 6 Jul 90 18:57:52 GMT
From: groucho![e-mail]  (Steve Emmerson)
Subject: Re: grim tidings for the future

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

>The point is that the taxpayer is really getting a good investment, the
>same a private industry expects for there money.

I'm a moderately informed taxpayer, and I *don't* believe I'm getting a
good investment.  The U.S space program strikes me as spending far too
much money for far too little return.  [Of course, I also feel that
other programs are even more wasteful.]

The point of this posting is to state that you don't speak for me and
that opinions should be labeled as such.

Steve Emmerson        [e-mail]        ...!ncar!unidata!steve

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

Date: 6 Jul 90 20:42:54 GMT
From: earthquake.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Re:  SPACE Digest V11 #592

In article <[e-mail]> [e-mail] writes:
>
>    * The error is in the primary mirror.
>  [etc]

From an informed source:

Dr. Ivan King of the UC Berkeley Astrophysics dpt, who did a lot of
camera development work on the Hubble and was at the operations
center for a good deal of time recently, has said the following:

The trouble is in the Primary mirror with high certainty.

They can image-process to totally correct for the problem, but
the effective light-gathering area is effectively 1/6 of what
it really is once they do the processing.

  == George William Herbert  ==   "Well, if an outraged Canadian terrorist was
 == JOAT for Hire: Anything,  ==  *** to come down and assasinate Quayle, what
=======Anywhere, My Price.======= ****** would happen?" -history prof _trying_
 ==   [e-mail]    ==  ************* to explain why WW I started...
  ==     ucbvax!ocf!gwh      == The OCF Gang: Making Tomorrow's Mistakes Today

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

Date: 6 Jul 90 07:02:02 GMT
From: agate!agate![e-mail]  (William Baxter)
Subject: Re: Nasa's budget


In article <[e-mail]> [e-mail] (Frank C. Paterra) writes:

>Expendible may be cheaper, but without any sort of space station
>currently, the shuttle is our only way of performing manned experiments
>in space.

Not really.  The Soviets have lots of unused launch capacity, and they
have arranged for foreign experiments on their space station.  They also
need hard currency.

--
William Baxter

ARPA: web@{garnet,brahms,math}.Berkeley.EDU
UUCP: {sun,dual,decwrl,decvax,hplabs,...}!ucbvax!garnet!web

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

Date: 6 Jul 90 11:19:24 GMT
From: agate!sandstorm.Berkeley.EDU![e-mail]  (Gordon J. Mohr)
Subject: HST <-> Manned Shuttle

--
Do the problems with the HST confirm the need for a manned space shuttle,
instead of unmanned expendables?

If so, could the problems have been introduced for that purpose? ;)

4:30am paranoia

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

End of SPACE Digest V12 #22
*******************