Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_351.TXT

Internet Message Format | 1991-07-08 | 19KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail
Received: from andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/andrew.cmu.edu.328.0.0>;
          Tue,  6 Sep 88 04:10:07 -0400 (EDT)
Received: from andrew.cmu.edu via qmail
          ID </afs/andrew.cmu.edu/service/mailqs/q001/QF.andrew.cmu.edu.23239d21.e1a147>;
          Tue,  6 Sep 88 04:09:06 -0400 (EDT)
Received: by andrew.cmu.edu (5.54/3.15) id <AB00322> for +dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl; Tue, 6 Sep 88 04:08:35 EDT
Received: by angband.s1.gov id AA01269; Tue, 6 Sep 88 01:05:29 PDT
    id AA01269; Tue, 6 Sep 88 01:05:29 PDT
Date: Tue, 6 Sep 88 01:05:29 PDT
From: Ted Anderson <[e-mail]>
Message-Id: <[e-mail]>
To: [e-mail]
Reply-To: [e-mail]
Subject: SPACE Digest V8 #351

SPACE Digest                                      Volume 8 : Issue 351

Today's Topics:
               status of Mars Observer
           Re: How does NASA detect a Hydrogen leak
         Transmutation (was: Interstellar Mining (?)
               Re: Satellite brightness
            Re: 95% vs. 99.9% reliability
           Re: Initials for the Uninitiated
           Re: Inverse SETI (Was:  ET phone home?)
           A request: forwarded NASA press releases
            Fuel Cells--How do they work?
            Re: 95% vs. 99.9% reliability
              Re: Orbital Mech Algorithm
            International Space University
----------------------------------------------------------------------

Date: 24 Aug 88 12:39:00 CDT
From: "ASUIPF::MC" <[e-mail]>
Subject: status of Mars Observer
To: "space" <[e-mail]>
Reply-To: "ASUIPF::MC" <[e-mail]>

Henry Spencer talks about the deletion of VIMS and the descope of the
altimeter from the Mars Observer mission:

> [NASA is being politically naive here:  what they ought to do is punt the
> decision to the scientists, which would probably have the same result but
> without the uproar being directed at NASA.]

Henry, you have a touching faith in the ability of the scientific community
to make non-political decisions.  However, as it turns out in this case,
the community was consulted, and these two instruments were the ones
recommended for deletion or descope.  Some of us with instruments
having less political support from the big guns in the community were
pleasantly surprised by this.

As of today as far as I know, VIMS is off completely though people are
looking at few-channel descopes of it, and the radar altimeter is being
replaced with a laser altimeter.  All the other instruments are still
OK, and the launch is still scheduled for 1992.  (Now that I think about
it I don't remember if part of the radio science experiment was taken
off or not.)  AvWeek has been doing a really terrible job of covering
the mission.

By the way, it's funny how nobody on the net seems to *know* anything
about Mars Observer: too busy whining about how the Soviets are doing
everything on Mars these days :-(

    Mike Caplinger, ASU/Caltech Mars Observer Camera Project
    [e-mail]
------

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

Date: 24 Aug 88 06:27:21 GMT
From: portal!cup.portal.com![e-mail]
Subject: Re: How does NASA detect a Hydrogen leak

I don't know about hydrogen, but for a scale, your typical air conditioning
repairman has a hand-held leak detector for freon leaks. These will reliably
detect a leak of one ounce freon per 10 (ten) years. These are cheap enough
to be a regular took kit item.

  --PLS

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

Date: 24 Aug 88 18:30:53 GMT
From: att!ihlpl![e-mail]  (Knudsen)
Subject: Transmutation (was: Interstellar Mining (?)

In article <[e-mail]>, [e-mail] (Steve Willner P-316 x57123) writes:
> Transmutation of elements typically takes about 0.1% of the rest mass
> energy.  This amount of energy corresponds to a speed of about 3% of
> light or about a 100 year trip to alpha Cen.  (Note: Piddly factors

> Speculating on the economics of advanced societies is a dubious
> proposition, but it seems to me that transmutation would be
> economically more attractive because of the shorter payback period
> and thus the lower cost of capital equipment.  In fact, I would turn

Unless I'm missing something, we should be able to transmute
small quantities of elements with current technology.
The FermiLab accelerator pushes protons to very near c,
enough to make them much "heavier."
Accelerating nuclei of heavier elements is more difficult,
since the neutrons makes the charge/mass ratio go down,
so you need stronger magnets or larger circular paths to
store the particles in while accelerating them a bit at a time
(they want to build a 10-mile diameter ring here in Illinois,
and they're already using superconducting magnets!).

However, that's just numbers.  A society with enough energy,
superconducting magnets, and payoff money for the farmers
could push any of the lighter elements to .03c whenever they wanted
to.  The trouble is that you don't manufacture very much matter at a
time this way, so you have to have lots of patience as well as
electricity.

I once read that the Atomic Energy Commission built a huge
machine to make Pu out of U by bombarding it with protons,
using simple electrostatic acceleration.  I no doubt have
the above all wrong, but the thing was run for several years.

Of course a spacefaring civilization making tungsten by
Casey-Jonesing a couple starships full of carbon would make
a heck of a good movie...

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

Date: 20 Aug 88 07:20:17 GMT
From: [e-mail]  (Eugene Miya)
Subject: Re: Satellite brightness

>Comments?
These seem a bit high.  I don't know how you are measuring these
magnitudes nor when.  Sirius, the brightest star in the sky isn't even
-2 in magnitude.  I hope you are not naked-eye balling them, a less than
reliable method.

Another gross generalization from

--eugene miya, NASA Ames Research Center, [e-mail]
  resident cynic at the Rock of Ages Home for Retired Hackers:
  "Mailers?! HA!", "If my mail does not reach you, please accept my apology."
  {uunet,hplabs,ncar,decwrl,allegra,tektronix}!ames!aurora!eugene
  "Send mail, avoid follow-ups.  If enough, I'll summarize."

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

Date: 22 Aug 88 17:30:09 GMT
From: [e-mail]  (Eugene Miya)
Subject: Re: 95% vs. 99.9% reliability

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Gregory N. Hullender) writes:
>>I imagine they would also have sent various officials from Morton Thiokol
>>and Nasa off to the Gualag, if not had them shot.
>
>Sounds like a fine idea to me.  A good many of them deserved it.

Yaw vol, mein herr, vhere do you vant us to line up?  Das thou plan to
pull the trigger, thein self?

>there would have been no shortage of
>volunteers to fly high-priority missions before definitive fixes were made.
>Bear in mind that you've seen a biased sample:  the safety-first astronauts
>like Sally Ride were the ones who got the publicity.

Well, we can see there's not schedule pressure in this newsgroup.
No one has brought up loss of a second craft if the first problem had not
be isolated.  I'm surprised to the contribution to greater loss of
"investment."  Also what ever happened to making making space safe
for every one [i.e., eventually doing away with astronaut requirements]
which everyone was interested for such a time?

Just a progression......

>>Fortunately, we don't live in the Soviet Union;

Oh!  Am I on the wrong side of the Pacific?

Anyways, let's get back on track shall we?

Another gross generalization from

--eugene miya, NASA Ames Research Center, [e-mail]
  resident cynic at the Rock of Ages Home for Retired Hackers:
  "Mailers?! HA!", "If my mail does not reach you, please accept my apology."
  {uunet,hplabs,ncar,decwrl,allegra,tektronix}!ames!aurora!eugene
  "Send mail, avoid follow-ups.  If enough, I'll summarize."

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

Date: 23 Aug 88 19:20:20 GMT
From: [e-mail]  (Eugene Miya)
Subject: Re: Initials for the Uninitiated

If there is enough interested, I will contact Ted Flinn (the Associate
Director of the Geodynamics program who used to read sci.space) for his
list of NASA acronyms (some in humor), and will place these on a
machine which should be FTP'able and I can try a crontab daemon as well.
If I get 5 AYs, I will do this.

Another gross generalization from

--eugene miya, NASA Ames Research Center, [e-mail]
  resident cynic at the Rock of Ages Home for Retired Hackers:
  "Mailers?! HA!", "If my mail does not reach you, please accept my apology."
  {uunet,hplabs,ncar,decwrl,allegra,tektronix}!ames!aurora!eugene
  "Send mail, avoid follow-ups.  If enough, I'll summarize."

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

Date: 24 Aug 88 16:43:17 GMT
From: attcan!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Inverse SETI (Was:  ET phone home?)

In article <[e-mail]> [e-mail] (Samudra E. Haque) writes:
>Also, once they received such a "carrier" signal from the
>electromagnetic spectrum, what would they do with it? They coudn't
>possibly know the modulation parameters (i.e., bandwidth, modulation
>techniques <am, fm, fsk, pcm, etc. etc.> or even chrominance and
>luminance coding mechanisms <pal, secam, ntsc> in that TV signal once
>they get it - if at all they do.

Assuming they can get the full signal (i.e. modulation, not just carrier),
the basic RF modulation shouldn't be hard to sort out.  That will get them
a video signal.  The sync pulses will be pretty obvious; if they have any
notion of video signalling at all, that will give them the basic line
structure of the signal.  Some of the distinctive stuff in the vertical
interval will give them the line count per frame.  If they use interlace --
they might not -- it won't be hard to figure that out either.  And given
the basic structure, it should not be difficult to get a *monochrome*
image out of it, although they might have trouble deciding black/white
polarity.  Sound and color are a different story:  they'll probably
realize that there is extra information there, but without some idea of
what it is or how it's encoded, sorting it out could be quite difficult.

In general, there are only so many ways to modulate things, and one can
study the signal rather than having to guess.  The tricky parts come when
the information is modulated or encoded in complex ways -- e.g. color --
*and* the information itself isn't very predictable.  (Color is a bad case
because our color-TV systems are very much tied to the color-perception
systems of our bodies.  An alien race might, for example, need more than
three primary colors to perceive a full-color image.)
--
Intel CPUs are not defective,  |     Henry Spencer at U of Toronto Zoology
they just act that way.        | uunet!attcan!utzoo!henry [e-mail]

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

Date: 25 Aug 88 01:37:46 GMT
From: [e-mail]  (Eugene Miya)
Subject: A request: forwarded NASA press releases

In article <[e-mail]> [e-mail] (David Smith) writes:
>Peter E. Yee writes:

Peter isn't writing these.  He's only forwarding them.  The real
authors (men [like Hugh Harris] and women you occasionally hear on
the TV or radio) have their names noted in the upper left hand corner.
Cite them.  Contact them.  Don't blame Peter.  He's just trying to do
you a favor.  Please edit accordingly.

Another gross generalization from

--eugene miya, NASA Ames Research Center, [e-mail]
  resident cynic at the Rock of Ages Home for Retired Hackers:
  "Mailers?! HA!", "If my mail does not reach you, please accept my apology."
  {uunet,hplabs,ncar,decwrl,allegra,tektronix}!ames!aurora!eugene
  "Send mail, avoid follow-ups.  If enough, I'll summarize."

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

Date: 23 Aug 88 06:02:59 GMT
From: stolaf![e-mail]  (henry m. pierce)
Subject: Fuel Cells--How do they work?


    What I know: fuel cells have been used to power manned space
craft.  They produce electricity to run the space craft's electrical
systems.  They work by reacting hydrogen and oxygen.

    What I want to know: To they produce an electic charge through
acid-base reaction of hydrogen and oxygen--or is heat water produced from
such a reaction used to run some sort of turbine? What voltage/amprage
are they able to produce? Are the analogus to a battery?

        thanks,

            Allways to have one more life than cats.

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

Date: 25 Aug 88 07:32:51 GMT
From: agate!stew.ssl.berkeley.edu![e-mail]  (Richard Link)
Subject: Re: 95% vs. 99.9% reliability

>Well, we can see there's not schedule pressure in this newsgroup.

Yo! Careful with that axe, Eugene!

I live and die according to NASA schedules. We can get our experiments
delivered on time. You wanna know how many launch dates have slipped?

Dr. Richard Link
Earth and Planetary Atmospheres Group
Space Sciences Laboratoy
University of California, Berkeley
[e-mail]

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

Date: 24 Aug 88 18:14:29 GMT
From: att!ihlpl![e-mail]  (Knudsen)
Subject: Re: Orbital Mech Algorithm

In article <[e-mail]>, [e-mail] writes:
>         Do
>           a = -G*M*r/|r|**3
>               v = v0 + a*dt
>           r = r0 + v*dt + 0.5*a*dt**2
>         Loop
>
>     Where r, v, and a are vectors, G is the gravitational constant, and M
> is the mass of the body being orbited.  This algorithm may not do well to
> figure when MIR will next be overhead, but it's good enough to give a feel for
> orbital mechanics.  More stuff can be added to the acceleration:
>
>     a = -G*M1*r1/|r1|**3 - G*M2*r2/|r2|**3 - ...
>             + thrust + any_other_acceleration

Hmmm, nice to see the extra 0.5*a*dt^2 term added to r.
This makes the integration by paralleograms instead of rectangles,
and more accurate.  I forgot to try that way back when.
To explain it, factor out the above equation to get
    r = r0 + (v + 0.5*a*dt) * dt
      = r0 + (average velocity this epoch) * time duration

>     The algorithm is plenty fast enough to do an engaging and enlightening
> simulation on the Mac, i.e., Orbital Mech (TM), even without the use of the
> floating point unit of the Mac II.  I wrote Orbital Mech to run on any Mac, and
> had to assume no FPU would be available.  I think you could do a pretty hot
> orbital simulator with an 80386 and FPU.

Some years ago I did the above on a Color Computer 1 in Basic09
(a sort of Pascal).  It ran amazingly fast even with the
grahics plotting.  I intended to add multiple bodies to it
(as the original poster mentions).  A nice feature of these
basic simulations is that multiple-body problems are obvious
extensions of the procedure, whereas analytical solutions
(usually giving elliptical orbits) can't even handle a 3rd body.

Anyway, everybody should try something like the above once,
if only to prove to wives, parents, etc. that graphics on
home computers are good for something besides games and pie charts.

PS: I recall working out some cute algebraic tricks to reduce
redundant computations for multiple bodies; maybe I got around
the damned square root needed to compute |r| in Cartesian.

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

Date: Thu, 25 Aug 88 10:12 EDT
From: Matt <[e-mail]>
Subject: International Space University

[Boston Globe, August 21, 1988]
           A space college launches its grades
Stars from 20 nations end 8 weeks at MIT studying the final frontier

By Alexander Reid
Globe Staff
   CAMBRIDGE - For nine weeks this summer, more than 100 young
visionaries from 20 counries cloistered themselves in the labyrinth of
classrooms and laboratories at the Massachusetts lnstitute of Technology
to research and discuss mankind's prospects in space.

   They are all in their 30s and 2Os and are considered the best and the
brightest in space research and exploration. And they are all, in the
words of Maria Antonietta Perlno, a nuclear engineer from Italy,
``exhilarated by the future in space.''

   In a short, ebullient ceremony yesterday morning, this group -
participants in the first academic Session of the International Space
University - marked the end of their time together in a graduation
ceremony at MIT.

   They talked of their experiments, of their late-night debates over
the virtues of Marxism and capitalism, of the frequent parties - but
mainly, they praised the spirit of international cooperation that was
nurtured by the nine-week session.

   Peter H. Dimandis, 27, director and a cofounder of ISU, called it
``the university's hidden agenda.''  ``Besides the research, the
technology and the ideas, we think we've begun to create a close network
of future world leaders in space exploration and development.  Space
travel should not be a one-nation endeavor. The intensity of the bonds
and the friendships we've seen here will eventually take us - mankind -
Into space.''

   Dimandis and Todd B. Hawley, 27, began the university at MlT last
year after raising more than $1.3 million through donations from
government, foundations and corporate sponsors.

   The 104 students were drawn from 350 applicants. They are considered
leaders in their fields of expertise, such areas as rocket propulsion,
political science and space architecture.

   The intent, explained Dimandis, himself pursuing a medical degree at
Harvard and a doctorate in aerospace engineering at MlT, is to ``create
a cross-disciplinary approach. The engineers and scientists should see
space travel from a political and legal standpoint and vice versa.
Anyone with a vision of space exploration should not be ignorant in any
of these areas.''

   The session was no picnic. Students, most financed by scholarships,
attended 240 hours of classes over the nine-week period.  Lectures were
given by experts from several of the most inifluential organizations in
the world space establishment.

  ``I'm here because I was impressed with the gall of an upstart group
of people to do something like this,'' said Daniel Norton, one of ISU's
30 faculty members and a specialist in space engineering at the Houston
Area Research Center. ''I was called by Peter last October and didn't
know him from Adam, but he seemed to represent a bunch of bright young
people with imaginative ideas, so I signed on. Their vision sold me on
this.''

   Perino, 28, was chosen by her fellow classmates to deliver one of
seven addresses during yesterday's ceremony.

  ''The only sad thing about this is this ceremony,' she said. ''It's
over. We enjoyed it so much. I have never seen such a high concentration
of the best information on space in one place at one time. I don't
profit by this. Neither does my country. The whole world profits.''

   Next year's session will be held in West Germany or France. By 1992,
said Dimandis, he hopes ISU will stand as an independent, fulltime
university.

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

End of SPACE Digest V8 #351
*******************