Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_4/V12_433.TXT

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Subject: SPACE Digest V12 #433

SPACE Digest                                     Volume 12 : Issue 433

Today's Topics:
             Re: Junk the shuttle
              Magellan Update - 10/05/90
              Re: Launch cost per pound
               Re: Beta Testers Needed
           Re: Mars Rover Update - 10/03/90
              deep space comm. protocols
              Magellan Update - 10/08/90
           Re: Mars Rover Update - 10/03/90
            Re: NASA Satellite TV Coverage
       Lifeless interplanetary travellers - where are they now?
                   Re: HST
        Re: Cost comparison: Apollo/Saturn vs. Shuttle
           Re: disposal of N-waste into sun

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: 8 Oct 90 13:17:15 GMT
From: rex!samsung!zaphod.mps.ohio-state.edu!rpi!crdgw1!gecrdvm1![e-mail]
Subject: Re: Junk the shuttle

In article <[e-mail]>, [e-mail] (Henry
Spencer) says:
>
>In article <[e-mail]> [e-mail] (Steve Hix)
>writes:
>>> Actually, we already invaded Washington (successfully!) some years
>>> ago. We decided to let you keep it, so we gave it back and returned to
>>> the True North, Strong and Free. (Well, maybe not free, but we can
>>> offer you a good deal :-))
>>
>>Assuming the price is right, can we move it to another location farther
>>south?  :}
>
>Any time you want to swap ends of the continent, just let us know.  We'll
>be happy to trade you Quebec for California. :-) :-)
OH, gee, like, I dunno. Fer shur I guess we could do that. That would
be, like, so fantastic. Tripendicular. NO, wait. maybe that would be
like, so grody, I mean, like, You guys tawk soo weird. But then, sayy
do you guys have narly hairdressers up there?

>--
>Imagine life with OS/360 the standard  | Henry Spencer at U of Toronto Zoology
>operating system.  Now think about X.  |  [e-mail]   utzoo!henry

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

Date: 8 Oct 90 17:17:46 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Magellan Update - 10/05/90


                         Magellan Status Report
                            October 5, 1990

     The Magellan spacecraft has now completed 147 mapping orbits, with
good data from at least 143 orbits.  The spacecraft and radar telemetry
continue to be nominal.  The solar array output of the spacecraft is at
1240 watts.  Seven star calibrations, two desaturations and fourteen
periods of DSN (Deep Space Network) coverage were successful in the past
24 hours.  One star crossing was rejected by the foreground filter because
it magnitude was greater than expected.  This will be corrected along with
updates of the radar parameters.

     The SAR (Synthetic Aperture Radar) Data Processing System has been
going through engineering tests and upgrades the past week in preparation
for normal operations on October 8. Three new F-BIDRs (Full-Resolution
Basic Image Data Record) were produced to verify the system.  The Image
Data Processing Team completed production of 29 full-resolution mosaics
covering the full length of the first 24 mapping orbits and 25 special
image products in the past week.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 6 Oct 90 19:55:34 GMT
From: swrinde!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!netnews.upenn.edu!msuinfo!sharkey!teemc!fmeed1![e-mail]  (Russ Cage)
Subject: Re: Launch cost per pound

In article <[e-mail]> [e-mail] (John Roberts) writes:
|>Not at all. It isn't a question of how much you are paid, it is a question of
|>how productive you are. If you are twice as productive, you are worth twice
|>as much. Western industry is far far more productive than Soviet industry so
|>it should be reachable.
|
|OK, so the Soviets are able to provide launch services for much less than
|the US, because they're less productive... I'm confused - I'll have to think
|about that for a while.

Look, John.  Despite Soviet workers being paid much less, our
productivity lets us make much more cost-effective airliners
and road vehicles.  Possibly, our superior manufacturing
capabilities could make Soviet-style boosters even cheaper
than the Soviets can sell them to us.
--
Russ Cage    Ford Powertrain Engineering Development Department
Work:  itivax.iti.org!cfctech!fmeed1!cage   (Business only, NO CHATTY MAIL PLS)
Home:  [e-mail]  (Everything else)
I speak for the companies I own, not for the ones I don't.

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

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From: [e-mail]
Subject:  Re: Beta Testers Needed

> From:         Leonard Abbey <[e-mail]>

> Wanted.....beta testers for sun/moon rise/set program.

It's been running just fine for 4.5 billion years; why bother beta-testing
it now?  :-)

    o       Chip Olson             bitnet: [e-mail]
 _ /-_      UMass-Amherst        internet: [e-mail]
(_)>(_)...........................   uucp: pick a path, any path.

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

Date: 8 Oct 90 17:00:14 GMT
From: elroy.jpl.nasa.gov!forsight!jato!mars![e-mail]  (Ron Baalke)
Subject: Re: Mars Rover Update - 10/03/90

In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>                    Mars Rover Update
>                     October 3, 1990
>
>The rover took four hours and twenty minutes to
>navigate a 109-foot-long course in Pasadena's Arroyo Seco, a dry
>riverbed adjacent to the Jet Propulsion Laboratory.

Correction:
The course the rover navigated was 109 METERS, not 109 feet.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 8 Oct 90 17:26:07 GMT
From: swrinde!zaphod.mps.ohio-state.edu!samsung!cs.utexas.edu![e-mail]  (Sean William O Malley)
Subject: deep space comm. protocols


I would like to present a deep space communcations
protocol to my networks class. Does anyone have
a good reference for such a protocol. I would like
to cover the error correction and retransmission
strategy used.

Sean O'Malley [e-mail]

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

Date: 8 Oct 90 17:58:09 GMT
From: snorkelwacker!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Magellan Update - 10/08/90


                       Magellan Status Report
                         October 8, 1990

     The Magellan spacecraft has now completed 170 mapping orbits of Venus,
with good radar data from at least 165 orbits.  Last Saturday, October 6,
Gyroscope B-2 again exhibited erratic behavior with increases in temperature
and motor current.  The gyroscope was initially marked as unusable and then
turned off to allow it to cool to 25 degress C.  It was turned on again, but
quickly heated to over 60 degrees C, so it was turned off and left off.
This gyro was in backup status, so the spacecraft's attitude continued to be
controlled by the other gyroscopes.

     The high power transmitter, TWTB, experienced a spurious shutdown on
October 7.  On board fault protections switched to TWTA, but 37 minutes of
radar playback data was lost due to the delay in reacquiring the signal
after reconfiguring for the change in signal polarization.  Magellan has
experienced prior spurious shutdowns in the TWTA, 4 in pre-launch tests and
5 in flight.  The investigation is being reopened of the TWTA shutdown model,
and contigency plans are being reviewed for quick responses to future
occurrences.

     All star calibrations since October 5 have been successful except for
orbit 544 (orbit since Venus Orbit Insertion) this morning, when one star
was missed.  All desaturations of the reaction wheels were nominal.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 8 Oct 90 18:04:37 GMT
From: sdd.hp.com!wuarchive!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: Mars Rover Update - 10/03/90

Was this Arryo one of those 'debris flows' they have out in the San Gabriel
Mountains? Something similar?

Phil Fraering
[e-mail]

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

Date: Mon, 8 Oct 90 13:21:56 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: NASA Satellite TV Coverage


>From: sam.cs.cmu.edu![e-mail]  (Vincent Cate)
>Subject: NASA Satellite TV Coverage

>I have been a bit disappointed in the coverage so far.  Most of the
>time when I have checked they have been showing mission control
>without any audio (talk about boring).  The second most common
>thing seems to be computer graphics.  Only once out of about 10
>times that I have looked have I actually caught them showing the
>output of a camera that was in orbit and it did not last very long.

>It amazes me that with cameras in orbit they are showing what they
>are (mostly boring ground based stuff).  Are they only able to send
>video from the shuttle during very limited portions of the orbit?
>Assuming this is the problem, does anyone know how limited this is
>and what portions (seems that near Florida might be good).

There have been many, many hours of orbital broadcast from NASA Select thus
far. At night, while the astronauts are asleep, the ground control people
have been playing with ("exercising") the payload bay cameras, focusing and
zooming in and out, adjusting the gain, and moving them around. Some of
the shots are of the inside of the bay, but mostly the cameras are pointed
at Earth. A spokesman comes on occasionally, and explains what's being
broadcast.

The video is lost when the Shuttle is out of range of a TDRS satellite.

There are cameras at both ends of the payload bay. On the day side, they
tend to show color pictures of Earth. On the night side, a black and white
camera is used, with the gain turned way up, so surface features can be seen.
One can frequently see flashes of lightning in the clouds. (!)

I think these pictures are very interesting, since they provide a better
impression than I have seen before of what it looks like in orbit (including
the apparent motion of the Earth).

There was one view which may have shown some star clusters (gain turned way up).

I also think the mission control coverage is somewhat interesting, at least
when there is audio.
      John Roberts
      [e-mail]

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

Date: 8 Oct 90 14:38:34 GMT
From: mcsun!unido!mpirbn![e-mail]  (Daniel Fischer)
Subject: Lifeless interplanetary travellers - where are they now?


Who can tell what has become of all those Upper Stages that were used in the
past 1.5 years to launch Magellan, Galileo and Ulysses? They were separated
from the spaceprobes after those had reached their escape velocity, so they
should be on similar orbits - what steps have been taken to increase their
distance from the S/C so that accidental collisions or electrical interference
are excluded? Galileo has made a swing-by at Venus that'll bring it to earth
two months from now - what has happend to the Galileo-IUS which should have
been on a rather similar trajectory? Will it also come close to earth again?
Or have Galileo's orbital correction maneouvres been so extensive to reach
Venus at all that the IUS is now somewhere completely else?

Magellan's IUS presumably didn't achieve an orbital insertion on Venus, so it
should also be on a heliocentric orbit: where will it go? And what will become
of Ulysses' PAM - not even to speak of the IUS that was separated after only
part of the 11.4 km/s were achieved [another question, BTW: the official ESA
paper in the ESA BULLETIN #63 speaks of 11.4km/s relative to earth, while
several U.S. media repeatedly talked of 15.2km/s - any explanations welcome].

And finally: where will Phobos-1 end up? It couldn't orbit-insert at Mars, so
will it return to earth on its Hohmann-style trajectory? When? (Might we catch
it and learn what we can do better next time? (-:) Phobos-2 as well as the
Viking-Orbiters should be in stable Martian orbits (though Phobos had come
rather close to the destination-moon - could it collide?), but I'm really
wondering whether somebody takes care of the whereabouts of the interplanetary
space debris. The pollution of earth's LEO and GEO is well-known by now, and
steps to protection are being taken (er, planned (er, talked about)) - but
who protects interplanetary space?

            [e-mail] / Daniel Fischer, Bonn, FRG

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

Date: 8 Oct 90 13:14:32 GMT
From: usc!samsung!umich!csd4330a!osl380a![e-mail]  (Ken Ellis)
Subject: Re: HST

I am interested in interferometric imaging at short wavelengths and would like
to find out more. I am familiar with the interferometric imaging work at UC,
Berkeley and at the University of Illinois, but not at Georgia. Could you point
me to some references or tell me who is doing the work? Thanks.

Ken Ellis
[e-mail]

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

Date: 8 Oct 90 16:20:29 GMT
From: zaphod.mps.ohio-state.edu!ub!ubvmsd.cc.buffalo.edu![e-mail]  (Craig L Cole)
Subject: Re: Cost comparison: Apollo/Saturn vs. Shuttle

In article <[e-mail]>, [e-mail] (Russ Cage) writes...
>The Soviets launch on expendables, and they return payloads and people
>from space all the time.  Apollo was an expendable, and it returned
>payloads from the moon.  Most any payload can be returned if it is
>designed for it (for instance, an integral aeroshell and recovery 'chutes).

What I meant to say was that the shuttle can return MUCH larger and
heavier payloads from orbit than expendables.

Really, the expendable itself doesn't return anything from orbit - the
payload itself does.

>Even Solar Max and Syncom did not require Shuttle.  Man-on-the-scene
>is all they needed to get them fixed; a particular vehicle is not
>implicit in making them functional again.  Skylab's thermal control
>system was refurbished on-orbit by workers in an Apollo (expendable).

Granted, Solar Max and Syncom didn't require the shuttle, only a
"man-on-the-scene," but other satellites did. (I can't remember their
names.) Nothing other than the shuttle could return those payloads.

Launching from the shuttle is no bargain, but I bet recovery is.
Designing an aeroshell and recovery chutes for a payload already
in space would cost quite a bit of time and money.

                                     Craig Cole
                                     [e-mail]
                                     [e-mail]

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

Date: 26 Sep 90 21:43:58 GMT
From: convex![e-mail]  (Dave Dodson)
Subject: Re: disposal of N-waste into sun

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (james d. Del Vecchio) writes:
>>>Launching things into the Sun is enormously expensive...
>>
>>Why would it be harder to send something to the sun than away from the sun?
>
>The direction is unimportant; what matters is the velocity change needed.
>To get something into the Sun, you have to kill *all* of Earth's orbital
>velocity (well, just about), and that's 30 km/s, a horrendous amount for
>chemical rockets.

Time for a little arithmetic here.  Let's use the following approximate
values for these constants:

Earth's Surface Escape Velocity        11 km/sec
Earth's Orbital Velocity around Sun    30 km/sec

A launch into the sun requires sqrt (11^2 + 30^2) km/sec =~ 32 km/sec.
This is so the payload, after having climbed out of the Earth's gravity
well, is travelling away from the Earth at 30 km/sec.  If the velocity
vector is in the opposite direction from the Earth's velocity vector
around the sun, the payload would fall into the sun.

A launch to solar escape requires sqrt (11^2 + (30^2)/2) km/sec =~ 24 km/sec.
This is so the payload, after climbing out of the Earth's gravity well, is
travelling away from the Earth at 30(sqrt(2)-1) km/sec =~ 12.5 km/sec.  If
the velocity vector is in the same direction as the Earth's, the payload would
have solar escape velocity and depart the solar system.

Thus solar impact requires 32/24 = 4/3 as much energy as solar escape.

All of these energy requirements could be reduced by using gravity assist
flybys of various planets, but would you want to jeopardize contaminating a
planet with radioactive debris in case of a navigation error or onboard
failure?

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

Dave Dodson                                     [e-mail]
Convex Computer Corporation      Richardson, Texas      [phone]

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

End of SPACE Digest V12 #433
*******************