From: "J. I. Blackshear Jr." <jib@bonnie.jsc.nasa.gov>
Subject: active planetary probes; should someone update the FAQ
Newsgroups: sci.space
There is also DSPSE (Deep Space Project Science Experiment) to be launched
in Jan 94...it will do 2.5 phasing loops about the Earth and enter Lunar
orbit on or about 21 Feb 94. It will stay in a 5 hour polar orbit with a periapsis altitude of about 425 km for about 65 days doing a complete
surface mapping of the Moon using the following cameras
UV/Visable
Near Wave IR
Long Wave IR
High Resolution Visable
once the mapping phase of the mission is up, we will depart the Moon and for a flyby of the near-earth asteroid 1620 Geographos on 31 Aug 94 as it crosses the ecliptic.
--
Jim Blackshear
jib@bonnie.jsc.nasa.gov
------------------------------
Date: 27 Oct 92 20:55:54
From: Wales.Larrison@ofa123.fidonet.org
Subject: Apollo - Southern Style with a side of grits
Newsgroups: sci.space
Bill Higgins proclaims:
>>>It worked, too. Southerners put us on the Moon. I don't think
>>>Yankees could have done it in eight years.
>
>> At Lewis there is a persistant rumor that they could not have
>>done it without some help from North of the Mason-Dixon line.
>>Unfortunately I don't remember the details. Was it something
>>about fuel type? or something about restarting engines in free-
>>fall? |-)
>
> I suppose I owe the Clevelanders an apology (apollogy?) for my
>glib overstatement. Heck, I'm a Great Lakes boy myself. Yes,
>there were a lot of Yankees involved. But when the days of Apollo
>are recounted, one hears a remarkable number of Southern accents
>(including the mixed German-Alabama accents).
And a few California drawls too, dude. They had something to do
with the Saturn Second stage (North American - Seal Beach,
California), and the F-1 and J-2 engines used on all of the Saturn
stages (Rocketdyne - Canoga Park, California), and the Apollo
Command and Service Modules (North American - Downey, California),
and the LEM ascent engines (TRW -- Redondo Beach, California), and
Skylab (McDonnell Douglas - Huntington Beach, California) and lots
and lots of other parts.
Let them Easterners argue about whose idea it was -- we know who
really designed and built the thing.... :-)
O.K., O.K., -- it was mostly SOUTHERN California. ;-)
And when the days of Apollo are recounted, it'll probably go like
this.....
Picture an old, retired ex-aerospace engineer sitting in his
rocking chair on his porch. His pocket protector, now faded yellow
with age. Rocking back and forth, back and forth, surrounded by his
grandchildren.
"Gee granddad, did you REALLY work on the Apollo program?"
"Yes grandson, I really did."
"Gosh granddad, could you tell us about it?"
"Certainly." The old, retired aerospace engineer fumbles under
the blanket on his lap.
He pulls out a slide projector remote control and a collapsible
metal pointer. He pulls the pointer to full extension and thumbs the
remote control on. The lights dim, a hidden projection screen drops
into place, and he starts to explain...
"Could I have the first vu-graph please??? ...."
[Sorry guys, I couldn't resist. An semi-inside joke among some
of us new-generation aerospace types. You'll get the punch line
when you recognize you start automatically writing along the long
axis on a pad of paper -- even when you're making up a grocery list.
And start wondering why they put portrait mode in as an option in
| Allen W. Sherzer | "A great man is one who does nothing but leaves |
| aws@iti.org | nothing undone" |
+----------------------178 DAYS TO FIRST FLIGHT OF DCX----------------------+
------------------------------
Date: 28 Oct 92 18:17:45 GMT
From: "Bruce W. Morlan" <morlan@afit.af.mil>
Subject: Comet Collision
Newsgroups: sci.space
rsb@mcc.com (Richard S. Brice) writes:
>>
>> >There is a greater change of dying from a train wreck or a car accident than
>> >getting plowed by the comet.
>>
>At the macro level, i.e. the interaction of planets, stars and comets, the
>universe seems to behave in almost clocklike manner; chance and probability
>have only a small role. ^^^^^
>Would anyone care to comment on how probability plays a role in the
>future interactions of earth and comet P/S-T and how much of the
>script is already written into the clock?
Sure. The script is nearly totally written. The Heisenberg uncertainty
associated with the objects in question (Earth, comet, Sun, other
planets, etc.) is practically 0 over the time frame in question. On the
other hand, the _uncertainty_ in the measurements leave much room for
surprises. I cannot comment on the measurement errors.
--
Bruce W. Morlan, Major, USAF Air Force Institute of Technology
Dept. Department Head AFIT/ENC
Department of Mathematics WPAFB OH 45433
------------------------------
Date: 28 Oct 92 12:06:21
From: Steinn Sigurdsson <steinly@topaz.ucsc.edu>
Subject: Comet Collision
Newsgroups: sci.space
In article <1992Oct28.181745.11840@afit.af.mil> morlan@afit.af.mil (Bruce W. Morlan) writes:
rsb@mcc.com (Richard S. Brice) writes:
>>
>> >There is a greater change of dying from a train wreck or a car accident than
>> >getting plowed by the comet.
>>
>At the macro level, i.e. the interaction of planets, stars and comets, the
>universe seems to behave in almost clocklike manner; chance and probability
>have only a small role. ^^^^^
>Would anyone care to comment on how probability plays a role in the
>future interactions of earth and comet P/S-T and how much of the
>script is already written into the clock?
Sure. The script is nearly totally written. The Heisenberg uncertainty
associated with the objects in question (Earth, comet, Sun, other
planets, etc.) is practically 0 over the time frame in question. On the
other hand, the _uncertainty_ in the measurements leave much room for
surprises. I cannot comment on the measurement errors.
Well, there is a bit more to it, for example for comet interactions
outgassing can be critical, particularly if the trajectory
has a future close encounter predicted with outgassing neglected.
A very small delta v at perihelion for very high eccentricity orbits
can produce very large phase errors a hundred orbits later.
With our current knowledge outgassing is unpredictable, I suspect
it is a critical phenomenon and is intrinsically unpredictable,
eg the cracking of crust due to superheated pockets of volatiles
may literally depend on the radioactive decay of C-14
better, the exact time cracking may in principle be triggered
by the decay of a single atom, for small enough pockets of gas ;-)
So, wenting of gas and resulting delta v may be quantum mechanically
uncertain at some level significant macroscopically...
* Steinn Sigurdsson Lick Observatory *
* steinly@lick.ucsc.edu "standard disclaimer" *
* The laws of gravity are very,very strict *
* And you're just bending them for your own benefit - B.B. 1988*
------------------------------
Date: 28 Oct 92 20:15:43 GMT
From: Thorsten Altenkirch <alti@dcs.ed.ac.uk>
Subject: Re:Swift-Tuttle Comet a threat to earth?
Newsgroups: sci.astro,sci.space
I understand that it is pretty unlikely that Swift-Tuttle will hit
earth in 2126. However, I would like to know what would happen in the
case such a big object would collide with our planet? I am not sure
whether my memory is right but in the discussion about the
disappearance of the dinosaurs an object of a size like 200m was
mentioned. Now, Swift-Tuttle is supposed to be much bigger (10 km?)...
--
Thorsten Altenkirch And there's a hand, my trusty fiere,
Laboratory for Foundations And gie's a hand o' thine,
of Computer Science And we'll tak a right guid-willie waught
University of Edinburgh For auld lang syne!
------------------------------
Date: 28 Oct 92 13:26:35
From: Steinn Sigurdsson <steinly@topaz.ucsc.edu>
Subject: Re:Swift-Tuttle Comet a threat to earth?
Newsgroups: sci.astro,sci.space
In article <ALTI.92Oct28201543@tanera.dcs.ed.ac.uk> alti@dcs.ed.ac.uk (Thorsten Altenkirch) writes:
I understand that it is pretty unlikely that Swift-Tuttle will hit
earth in 2126. However, I would like to know what would happen in the
case such a big object would collide with our planet? I am not sure
You die, I die, Everybody dies!
whether my memory is right but in the discussion about the
disappearance of the dinosaurs an object of a size like 200m was
mentioned. Now, Swift-Tuttle is supposed to be much bigger (10 km?)...
Nah, P/Swift-Tuttle is barely a dinosaur killer with
worst case diameter estimates - if you assume low albedo
it is 10 km across, likely it is a little smaller,
not quite enough to kill 50%+ of species, more of
a civilization killer and 10% extinction (of species,
higher fraction of individuals would die).
So figure a few billion humans and complete death
on continent scale depending on where it hit.
| Steinn Sigurdsson |I saw two shooting stars last night |
| Lick Observatory |I wished on them but they were only satellites |
| steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? |
| "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 |
------------------------------
Date: 28 Oct 92 22:24:05 GMT
From: train@ccwf.cc.utexas.edu
Subject: Recognizing a Dyson sphere if you saw one
Newsgroups: sci.astro,sci.space
In article <kHXBTB8w165w@west.darkside.com> max@west.darkside.com (Erik Max Francis) writes:
>train@ccwf.cc.utexas.edu writes:
>
>> I may be wrong about this, I forget the aprroximate size of a dwarf star and
>> wouldn't be anything near the size of a dwarf star would it? I thought dwarf
>> stars, at least white dwarfs, were about the size of the Earth.
>
>"Dwarf" usually means main-sequence dwarf, which is the same class of
>star that the Sun is. Main-sequence stars can be all sorts of sizes,
>ranging from very large and massive O or B stars to very dim and cool M
>stars. Our sun, a G2 V main-sequence star, is above average, though.
>
Yes - these things I already know. I was trying to make a point to the original writer of the original post (wherever is is now) that a sphere with the radius
of the earth's orbit (1AU) won't be a dwarf as he/she (i forget) thought it might be. If it has a radius of 1AU, the star would be a giant or supergiant.
