Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_6/V13_602.TXT

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Subject: SPACE Digest V13 #602

SPACE Digest                                     Volume 13 : Issue 602

Today's Topics:
           Re: Should Galileo be rerouted?
      Re: Fred vs. Exploration: head-to-head competition
               Re: Saturn V and the ALS
                  lifeboats
         Re: Fred cut, AXAF and SIRTF funded
       What can be done without government interference
        Re: Tethers (was Re: Laser launchers)
       MAJOR SOLAR FLARE ALERT - PROTON IMPACT POSSIBLE

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
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----------------------------------------------------------------------

Date: 18 May 91 17:48:37 GMT
From: snorkelwacker.mit.edu!spool.mu.edu!munnari.oz.au!uhccux![e-mail]  (David Tholen)
Subject: Re: Should Galileo be rerouted?

Henry Spencer writes:

> There is, however, a small problem in that the probability of good results
> from the asteroid encounter(s) is much higher if optical navigation is
> available during the approach.  The asteroids' positions simply are not
> known all that accurately.  Without the main antenna to send approach
> images back to Earth quickly, the cameras will have to be pointed by
> guesswork.  My recollection is that the imaging people were worried enough
> about pointing *before* the antenna problem appeared...

Optical navigation will still be done, though the last image will be
obtained five days out instead of one day out; it takes four days to play
back an image.  Groundbased astrometry has taken on added importance as a
result, and we are working at beefing up our monitoring.  We've measured
Gaspra's position three times this past week and hope to continue with
weekly measurements.  Even so, the error ellipse will likely be large
enough to result in some fraction of blank images.  Yes, this was true
even before the antenna problem developed.  We are working to minimize the
number of blank frames.

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

Date: 18 May 91 21:24:42 GMT
From: sdd.hp.com!think.com!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Fred vs. Exploration: head-to-head competition

In article <[e-mail]> [e-mail] writes:
>>The "funding" to which *you* were referring was the hypothetical $10G
>>peak Fred budget.  I stand by my comments:  no space project will ever
>>see that money if Fred dies.
>
>You don't ignore my postings, you fail to read them correctly.
>I was in fact referring to the _current_ saving of SIRTF and AXAF
>by the cutting of Fred in the Congressional committee...

Ah, so that's why your attention span is so short:  your memory is going.
To quote <[e-mail]>:

> Even a _momentary_ effect is enough to pay for SIRTF, AXAF,
> a greatly expanded ground-based visual search, a greatly expanded
> Antartic asteroid sample return mission, _and_ a gaggle
> of small infrared probes launched into the meteor showers.
>
> That's right, _all_ of that, spread over several years, costs just
> one year of peak Fred funding (c. $10 billion by GAO estimates).

No, Nick, a momentary effect won't pay for these things... unless that
"momentary" effect somehow gives planetary science at least the equivalent
of a year of Fred's supposed peak funding, as you suggested.  Dream on.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 19 May 91 02:59:32 GMT
From: agate!bionet!uwm.edu!zaphod.mps.ohio-state.edu!samsung!umich!ox.com!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: Saturn V and the ALS

In article <[e-mail]> [e-mail] (Frank Crary) writes:

>>That figure came from the LLNL Great Exploration Study. Their station
>>cost about $1 billion. I doubled it.

>The costs and schedules in LLNL's Great Exploration are questionable. They
>reduce launch costs by having the government offer to pay $250/lb (or
>a similar figure) for supplies transported to orbit.

The figure is closer to $1,000/lb which I do not consider a similar
figure. They have two contractors who agree to provide launch services for
that price. Even if they cannot, this has little effect on the LLNL
Space Station since it only requires one HLV launch.

>high rates, using new-and-cheaper launchers within two years.

I have their schedule in front of me (LLNL doc 90-402) and it has the
first launch at just under three years after program start. This is
compatable with the schedules Martin and McDonnell gave SDIO for
the Zenith Star HLV's.

>They also
>assume "success oriented planning" that is, that everything will work as
>planned and on budget, with no money spent on contingencies or any margin
>for error.

Actually, I think they have very wide margins for error. However, you
will note that I have doubled the cost of both the HLV development
AND the station development. It still comes in cheaper then flying
the Shuttle for a year.

>These are EXTREMELY optimistic assumptions.

Both the NASA work on inflatables and the study by a major NASA contractor
with similar experience (ILC Dover) say the approach is workable within
existing technology.

>I was refering, rather, to the guidance and control systems (no to mention
>manuevering rockets and fuel) needed to approch and dock to the station.

You are correct here. They will need the HLV to go up and let's tack on
$1B for the modifications (about the cost of the original Spacelab
development). In that case it may take a bit more than one years Shuttle
savings to pay for it.

We are still getting hundreds of times more science for far far less
cost.

>>Some are designed to have components replaced. Remember Solar Max?

>Designing them in this way drives up their mass.

The HLV which results from this program reduces cost to LEO by a factor
of three. That should make up for any extra mass. If not, the extended
lifetime should.

>In any case, are you assuming
>that the only on orbit repairs will be the replacement of failed "black-boxes"
>with the new parts shipped up from Earth. (Not a bad assumption, but I had
>the impression you meant something more...)

Eventually I do but it needs to be bootstraped. Eventually we will do
all the integration in space. This will reduce cost and add to reliability.
If Galelio where integrated in space it would have gone directly to
Jupiter. In addition, it wouldn't need all the complex mhanisms used
to unfold its antenna. A direct result of this would be people at JPL
getting a lot more sleep.

  Allen

--
+---------------------------------------------------------------------------+
|Allen W. Sherzer |        Allen's tactics are too tricky to deal with      |
|   [e-mail]   |             -- Harel Barzilai                           |
+---------------------------------------------------------------------------+

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

Date: 19 May 91 02:36:24 GMT
From: swrinde!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: lifeboats

In article <[e-mail]> [e-mail] (Frank Crary) writes:
>I don't think the command module alone could serve as a crew transport. Such
>a transport would require at least 48 hours of autonomus power and life
>support capability ... If I remember correctly, the
>Apollo CM has almost NO independent capability (e.g. it needs a service
>module, execpt for a very short time before and during reentry.)

Adding power and life support should be a simple matter of another battery
or two and another tank or two.  The CM had plenty of equipment that would
be largely superfluous in this role, so there should be no serious problem
finding room and mass for such minor changes.

The one SM function that would have to be provided by new hardware would
be retrofire.  The obvious method is a set of small solid motors a la Gemini.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 19 May 91 03:49:12 GMT
From: sdd.hp.com!spool.mu.edu!uwm.edu!linac!unixhub!slacvm![e-mail]  (Jon J Thaler)
Subject: Re: Fred cut, AXAF and SIRTF funded

In article <[e-mail]>,
[e-mail] (Frank Crary) says:

         [...stuff deleted...]
>             In no way does this mean that these programs benifited from
>Freedom being zeroed. It means that they were not hurt because of it. There
>is a BIG difference between gaining money and not loosing money. (If your
>boss does not give you a raise, could you say that he gave you money, since
>he chose not to fire you?)

It seems to me that the two sides in this argument are talking about two
different things.  My understanding of the history of the budget is (I'm
sure I'll be corrected if I'm wrong):

* When the budget was submitted:
  The President's budget is (as usual) declared "dead on arrival," because
  his spending priorities are not the same as the Democrats'.  At this
  point, there isn't necessarily a one-or-the-other choice to be made
  about space projects.

* Last week:
  The total NASA budget had already been (more-or-less) determined, and
  the vote was on how to allocate $700 million or so of money.   This
  was directly a this-or-that choice.

So, the two sides are talking about the budget as it existed at two different
times.

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

Date: 19 May 91 14:38:16 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!mips!spool.mu.edu!news.nd.edu!mentor.cc.purdue.edu!pop.stat.purdue.edu![e-mail]  (Herman Rubin)
Subject: What can be done without government interference

In article <[e-mail]>, [e-mail] (Allen W. Sherzer) writes:
> In article <[e-mail]> [e-mail] writes:
>
> >>There is a middle ground between our current socialistic approach and
> >>total government non-involvement (nither of which will work IMHO).
>
> >We've never tried a totally non-government approach, actually, so
> >it is hard to say how it would turn out.
>
> No large infrastructure project has ever been done without major
> government involvement.

I disagree.  I do not know of any, although I believe that even some of thes
must have occurred, without government acquiescence, but certainly there have
been many without government involvement.  That is, unless you consider setting
up an infrastructure, or even a government, involvement of the original
government.

The Massachusetts Bay Colony was set up by the Puritans, with at most grudging
acceptance by the British Government.  I doubt that when Roger Williams founded
Rhode Island he had any government backing.

On a different note, we have the Amish, Shaker, and other religious communities
in the US and elsewhere.  We have the kibbutzim in Israel, many started well
before a separate state; these are, in many cases, the size of towns. Also, it
is clear that the Mormons did not have government backing when they settled
in Utah.  We have the development of the clipper ships in the 19th century.
The gold rush occurred before the government could even get organized.  The
taking over of India by the British, including the setting up of a massive
infrastructure, was done by the British East India Company, NOT a branch of
the British government, although the British military cooperated.  Only later
did the British government get in.

There are millions who support major space activities.  I do not say that
some organization is not needed, but anything more than permission from
existing governments is unnecessary.

--
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: [phone]
[e-mail] (Internet, bitnet)   {purdue,pur-ee}!l.cc!hrubin(UUCP)

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

Date: 19 May 91 07:28:36 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!news-server.csri.toronto.edu!torsqnt!hybrid!torag!w-dnes![e-mail]  (Walter Dnes )
Subject: Re: Tethers (was Re: Laser launchers)


[e-mail] (Christopher Neufeld) writes:

> In article <[e-mail]> [e-mail] (Gary Coffman) writes:
> >
> >Let's look at a typical strawman tether launch. Let's propose a 1000 km
> >tether whose center of mass is in a 700 km orbit. To hook on to the
> >lower end of the tether, you need to be going faster than the orbital
> >velocity of a 700 km orbit and be at an altitude of 200 km. If you've
> >already gone that far, you've paid most of the cost to orbit.
> >
>    No, that's not right. If the tether is rotating, resembling the spoke
> of an invisible wheel rolling around the surface of the Earth, then the
> velocity of the tip drops to zero briefly. A person standing on the
> ground would see the tether come in from a high angle, straightening out
> until it was coming straight down, stop, then take off in the upward
>
     "If the tether is rotating..." W-H-O-A !!!!!!!!!!!!!!!!!!

     ( w = omega, MS-DOS can handle it but other character sets
are different. ) Let's see... orbital velocity is approximately
7 km/sec at that altitude. Assuming that the tether is as above,
you've got 500 km of tether rotating with the end moving at
7 km/sec.
                 wr = v

                      v    7
                  w = - = --- = 0.014 radians/sec
                      r   500

    A small section length dr will have mass kdr where k is the
linear density. a = v * v / r = w * w * r at any radius r.

     Let's assume a cable of material X (neutronium ?) The 500 km
section would have a centrifugal/centripital tug of...

                /~ 500 km      /~ 500 km
Ascii           |              |          k(wr)^2   evaluated at
integral   F =  | ma    = kw^2 | r dr  =  -------   r = 500 km
sign           _/             _/             2
                 0 km           0 km

     But we started off with wr = 7 km/sec, so we're looking at


     k(wr)^2   k(7km/sec)^2   k(49000000m^2)   k(24500000)m^2
     ------- = ------------ = -------------- = --------------
        2           2             2sec^2           sec^2

                                               k(500000m)*49m
                                             = ---------------
                                                   sec^2
     but 500000m = 500km
     since k is the linear density
     k(500000)m = mass of the 500km section of tether
     49m/sec^2 = approx 5 g's
     This is one half of the tether. Newton's 3rd law implies that
the other portion has identical force *IN THE OTHER DIRECTION*.
Also 5 times the earth-surface weight of the tether. And we were
worrying about whether the tether would hold up under its own weight.
At this point gravitational force becomes a secondary mechanism in
the process of tearing the structure apart. Back to the drawing
board...

Walter Dnes
--------------------------------------------------------------------------
[e-mail]             [e-mail]
...hybrid!torag!w-dnes!waltdnes  [e-mail]

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

Date: Sat, 18 May 91 01:14:49 MDT
From: oler <@BITNET.CC.CMU.EDU:[e-mail]> (CARY OLER)
Subject: MAJOR SOLAR FLARE ALERT - PROTON IMPACT POSSIBLE
X-St-Vmsmail-To: st%"[e-mail]"

                        --  MAJOR SOLAR FLARE ALERT  --

                                 MAY 18, 1991

                            Potential Proton Impact
                              Flare Event Summary
                          Potential Impact Assessment


                                    --------



MAJOR ENERGETIC EVENT SUMMARY

     A major energetic flare erupted from Region 6619 early in the UT day of
18 May.  The event began at 04:37 UT, peaked at 05:45 UT and has not yet
ended as of this writing (06:40 UT).  This event was rated a powerful class
X2.8/1N Tenflare, and was unusually long in duration.  The integrated x-ray
flux from this flare is high, rated so far at near 1.00 Joules/meter^2. A
moderate intensity Type II sweep was observed together with a weak Type IV.
The 2695 MHz emission was measured at 5,700 s.f.u..  The flare was located at
N32W84 and may have ejected protons.  These figures are preliminary.

     There is a moderate risk for a satellite proton event to begin near
16:00 UT on 18 May.  Proton levels could exceed 200 p.f.u. at that time.
Polar latitudes are alerted to the potential for minor PCA activity and/or
a polar cap disturbance affecting polar radio communications and navigational
systems.  Increased levels of absorption could introduce errors in
navigational signals passing through or near the polar latitudes.  If a flare
shock arrives from the previous class M8.9 major flare of 16 May (which is
expected sometime near 12:00 UT on 18 May), the latitudinal boundary of polar
ionospheric absorption could migrate equatorward, affecting a larger area
than might normally be expected.  Radio communicators and navigators should
be aware of the increased threat for proton-related disturbances.

     Region 6619 maintained a stable configuration since the last major class
M8.9/2B flare of 16 May.  No change in size or apparent spot configuration
was observed during the period prior to this major X-class flare.


POTENTIAL TERRESTRIAL IMPACT ASSESSMENT

     Aside from the possible proton impact mentioned above, no significant
terrestrial geomagnetic impacts are expected from this event.  Region 6619 is
very near the west limb and will be out of view on 19 May.  This region will
still remain capable of producing terrestrial flare-effects (SIDs/SWFs and
proton activity) until it rotates further beyond the west limb.  The
Potential Major Solar Flare Warning will remain in effect until further
notice.

     The other regions currently visible are not capable of producing major
flare activity.  At best, only isolated low-level M-class flares will be
possible from these regions, with a higher probability for C-class flares.
Once Region 6619 rotates beyond the west limb and out of influential range,
solar activity will likely return to low levels, with occassional periods of
moderate activity.


WARNINGS CURRENTLY IN PROGRESS:

   -  POTENTIAL GEOMAGNETIC STORM WARNING (18-19 MAY)
   -  LOW LATITUDE AURORAL ACTIVITY WATCH (18-19 MAY)
   -  POTENTIAL MAJOR SOLAR FLARE WARNING


**  End of Alert  **

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

End of SPACE Digest V13 #602
*******************