After the meteor from last year passed withinn 4 minutes of the earth (the
large one), I was wondering if we have any system of avoiding these
large beasts??!! I read that if it hit the earth, millions could have died.
With a problem like this, surely there must be some defence!!!
Anyone know anything about it???
Thanks
Jhagon
... Our galaxy is just a figmant of someones bad imagination!!!
--- Blue Wave/RA v2.10 [NR]
* Origin: Coffee Au Go-Go. We don't know what it means either.
(3:680/820.0)
------------------------------
Date: 24 Jul 92 03:12:00 GMT
From: University Space Society <st17a@judy.uh.edu>
Subject: More Lunar Resource Mapper Information
Newsgroups: sci.space
Here is some more Lunar Resource Mapper information that I have gleaned from
publications and proceedings. I hope this is of some interest.
Gamma-Ray and Neutron Spectrometer for the Lunar Resource Mapper
One of the early Space Exploration Initiatives will be a lunar orbiter to map the
composition of the Moon. This mission is needed to support further lunar exploration
and habitation and will provide a valuable dataset for understanding lunar geological
processes. The payload will consist of the gamma-ray and neutron spectrometer
discussed here, an X-ray fluorescence imager, and possibly one or two other
instruments. The spacecraft will be small (<100 kg), built on a fast schedule (about three
years), and have a low cost (about $100M including launch). Launch is tentatively
scheduled for April 1995. The program will be similar to the ALEXIS (Array of Low-
Energy X-ray Imaging Sensors) program at Los Alamos, which is scheduled to be
launched as a small satellite in April 1992.
Most gamma rays used to map lunar elements are in the energy range of 0.2-8
MeV. The gamma-ray detector will contain a ~70% efficient [relative to a 7.62-cm-
diameter x 7.62-cm-length NaI(Tl) scintillator] n-type germanium crystal. N-type is used
because it is much less susceptible to radiation damage than p-type germanium. No
annealing is planned because the radiation damage accumulated in the one-year
mission will not seriously degrade the energy resolution if the crystal remains below 100
K. Because a Stirling cycle cooler will be used, the crystal will be mounted ustechniques commercially developed in recent years for operating germanium detectors
on vibrating platforms. A bismuth germanate (BGO) anticoincidence shield on the sides
and back of the germanium crystal will eliminate most events due to charged particles,
gamma rays produced by cosmic rays incident on the spacecraft, and Compton-
scattered events in the crystal. A plastic scintillator over the nadir-pointing surface of the
germanium crystal will provide a similar capability in the forward direction without
significantly attenuating the gamma-ray flux from the Moon. The gamma-ray detector
will be on a short boom to further reduce the background from the spacecraft.
The critical issue for operating a germanium detector in space is the method of
cooling. For short missions, stored cryogens such as liquid nitrogen, solid methane, or
solid argon have been proposed. For longer missions a passive radiator, as used on the
Mars Observer, or an active device, such as a Stirling cycle cooler, is required.
We have chosen not to use a passive radiator because of the complications in
shielding the radiator from the Sun, Earth, and Moon when the spacecraft is in a polar
orbit and instead have chosen to use the British Aerospace Stirling cycle cooler based
on the Oxford design. This closed-cycle mechanical cooler is designed for a 10-year
lifetime and has operated successfully in the laboratory without maintenance for over
three years. Two of these miniature cryocoolers were launched on 12 September 1991
as part of the ISAMS multichannel infrared radiometer on the Upper Atmosphere
Research Satellite, and they are still operating successfully. Research is being done on
these coolers (1) concerning vibration, thermal performance, and reliability.
Because the germanium detector energy resolution is degraded by vibration, we
also will use a pair of these coolers with two compressors and two expanders mounted
back to back to minimize vibration. In addition, we will use a low-distortion electronic
feedback system to minimize harmonics and a flexible vibration decoupler between the
expander cold tips and the germanium crystal.
A neutron detector is required because it provides maximum sensitivity for
hydrogen and hence water. Data from the gamma-ray detector and the neutron detector
are complementary because the neutron flux, which produces most gamma rays, is
needed to normalize the gamma-ray line intensities; in turn, the gamma-ray dattermine the composition of the lunar surface and hence the moderation of
neutrons by elements other than hydrogen (2).
Three different sensors are used to measure the neutrons in three energy
ranges. Thermal (E(sub)n ~ 0.01-0.4 eV) neutrons are measured with a bare ^3He
proportional counter, epithermal (E(sub)n ~ 0.4-10^3 eV) neutrons with a ^3He
proportional counter wrapped with thermal-neutron-absorbing cadmium, and fast
(E(sub)n ~ 0.5-10 MeV) neutrons with a plastic scintillator and ^3He proportional counter
operated in coincidence (3). The thermal se the epithermal sensor will be
mounted on a short boom opposite the gamma-ray detector boom to reduce neutron
backgrounds. Ratios of the three count rates are very sensitive to the amount of
hydrogen in the lunar surface (4).
The gamma-ray and neutron spectrometer will provide data on almost all
elements over all of the lunar surface. Published estimates of the detection limits for
similar detectors range from 0.016 ppm for uranium to 1.3% for calcium (5). We
estimate a hydrogen detection limit of 100 ppm based on the neutron detector (4). The
spatial resolution is about 140 km x 140 km, which is determined by the orbit altitude of
100 km (6). Both gamma rays and neutrons sense the elemental composition of the
lunar surface to depths of tens of centimeters. The data from this instrument will
complement the data from the X-ray fluorescence imager (7), which has a resolution of
1 km x 1 km for six elements.
[Figure 1, which appears in the hard copy here, shows the schematics of a genegermanium detector with a split cycle Stirling cooler (adopted from 5) and the neutron
sensors for thermal, epithermal, and fast neutrons.]
Work supported by NASA and done under the auspices of the US DOE.
References
(1) Ross R. G. et al. (1991) Advances in Cryogenic Engineering, 37, in press.
(2) Reedy R. C. et al. (1992), this workshop.
(3)Jenkins R. W. et al. (1970) J. Geophys. Res., 75, 4197-4204.
(4))Feldman W. C. et al. (1991) Geophys. Res. Lett., 18, 2157-2160.
(5) Metzger(6) Reedy R. C. et al. (1973) J. Geophys. Res., 78, 5847-5866.
(7) Edwards B. C. et al. (1992), this workshop. Edwards B. C.* Ameduri F. Bloch J. J.
Priedhorsky W. C. Roussel-Dupre D.Smith B. W.
Sorry about the slight overrun. I am still learning how to do this stuff. If
someone can grab this and reformat, go for it. Thank you
Dennis, University of Alabama in Huntsville
------------------------------
Date: 23 Jul 92 23:05:15 GMT
From: "Phil G. Fraering" <pgf@srl01.usl.edu>
Subject: Star Trek - instrumentation
Newsgroups: sci.space
roberts@CMR.NCSL.NIST.GOV (John Roberts) writes:
>-From: games@max.u.washington.edu
>-Subject: Re: Star Trek and public perception of space/science/engineering
>-Date: 20 Jul 92 18:10:51 GMT
>-And then there are the tricorders. These things have NO visible information
>-display. Just how do you get a diagnosis down to the synapses when all the
>-user is looking at are flashing LEDs.
>It's that great Star Fleet Academy training they all get. Don't you wish you
>could take a 1-week survey course there now? At least I can look at an
>oscilloscope display and derive a lot of information from what to a layman
>would be a meaningless squiggle. :-)
>The new version is better than the old Star Trek, in which Mr. Spock got most
>of his information by looking into a blue light bulb!
>I recently had a day off, and watched an old rerun of "Voyage to the Bottom
>of the Sea". The displays on the submarine are really spectacular - the main
>feature is a large grid of light bulbs that shows two 2-digit numbers, slowly
>incrementing. :-) The digits are about a foot high.
Actually, I sorta liked the displays in 2010, so much that I want
one of those telescope thingies they used to look at the monoliths
eating Jupiter. Although it is implied that the data processing unit
being used to enhance the image was HAL...
BTW, has anyone noticed in all the pictures of the new visual
phones coming out, the cameras look like HAL consoles?
--
Phil Fraering pgf@srl0x.cacs.usl.edu where the x is a number from 1-5.
Phone: 318/365-5418
"There are still 201969 unread articles in 1278 groups" - nn message
"57 channels and nothing on" - Bruce Springsteen
------------------------------
Date: 23 Jul 92 18:54:27 GMT
From: Robert Nychka <stu5s33@bnr>
Subject: Star Trek and public perception of spa
Newsgroups: sci.space
> About the terra-forming thing, and someone saying we shouldn't
>do it unless we're *SURE* we're not killing any strange life forms...
> unless someone is first willing to define "life", this
>discussion borders on meaningless. Now don't look at me, I
>wouldn't begin to even try to formulate such a definition.
> Just so we all are aware of limitations here.
This is assuming that if terraforming WAS an alternative to discovering 'ready made' planets that the juristiction of existing government and the ability for an individual NOT to terraform will exist. As it stands now, life forms are by no means an excuse to stop development of private concerns, let alone a deterent in starting a new world.
Species of animals are presently destroyed every year for expansion, the quest for a new world isn't going to make someone more concerned about the concept of destroying life. It will probably make us less tolerant due to the fact that HUMAN survival preceeds that of ANY race or animal.
Robert Nychka
-these opinions are my own and not that of my boss.
------------------------------
Date: 23 Jul 92 22:37:26 GMT
From: Bob Tidrick <bobt@pogo.wv.tek.com>
Subject: Star Trek and public perception of space/science/engineering
Newsgroups: sci.space
In article <1992Jul23.174448.18038@magnus.acs.ohio-state.edu> bmartino@magnus.acs.ohio-state.edu (Bob Martino) writes:
> unless someone is first willing to define "life", this
>discussion borders on meaningless. Now don't look at me, I
>wouldn't begin to even try to formulate such a definition.
Could it not be something as simple as "A combination of chemical bonds
capable of replicating itself."? Basicly that is what DNA is. Who knows what
else is capable of this. Did you ever see "The Andromida Strain"? If it can't
reproduce itself eventually it will physicaly cease to exist.
If anything was found on Mars that exibited this property I would say "leave
it alone!" We have no business disturbing something which may one day evolve
into a more complex form. However if nothing is found than it is a mear rock
and we have dibs.
--
Bob Tidrick
GPID Engineering
Tektronix Inc.
Wilsonville OR.
------------------------------
Date: 24 Jul 92 01:26:55 GMT
From: Dmitry Gringauz <conan!dmitry>
Subject: Star Trek and public perception of space/science/engineering
Newsgroups: sci.space
In article <pgf.711672356@srl03.cacs.usl.edu>, pgf@srl03.cacs.usl.edu (Phil G. Fraering) writes:
> I know I'm not the only one who has noticed that bioengineering and
> genetic engineering has always been presented negatively, in
> _both_ Star Trek series... Hell, if anyone ever starts a terraforming
> project somewhere, you know some Professional Idiot over in Congress
> or Parlaiment or the Diet or the Supreme Soviet is going to stand up
> and say "But how do we know there isn't some life there we can't even
> begin to imagine, like that episode of Star Trek?"
This probably belongs in one of the talk.politics groups, but as long as
you mention Supreme Soviet, I might as well say my opinion. Those guys
(pre-august coup) have, in fact been engaged in large-scale terraforming
(or desert- or swamp-forming) for the past 70 years, without any regard
for any lifeforms that were present in the terraforming areas. I can site
a lot of examples, starting from huge water reservouirs build in Central
Asia with the help of "peaceful" nuclear explosion, and ending with almost
completely stopping the water flow in Volga and Neva rivers -- the former due
to excessive construction of hydra-power generating plants, the latter
due to the construction of the controversial damb that was suppose to
protect St. Petersburg from once-in-a-century floods.
Same goes for bioengineering. Rumor had it for quiet some time that the
soviet biowarfare engineers have developed strains of plague that can
affect people of only one gender (male, of course), and of a certain age
(18-55 usually). The evidence to that is an outbreak of plague in one
of the cities in Urals. Out of 30-some victims of the
outbreak, there was only one female, the rest were male ages 20-50 (approx.
range).
So there is nothing really new or amoral about bioengineering and terraforming
over the existing life forms. It has been done before, it will be done
again.
>
> Pessemistically Yours,
>
> Phil
Just as pessimistic,
Dmitry
------------------------------
Date: 24 Jul 92 04:33:15 GMT
From: Steve Pattinson <steve@lewis.OZ>
Subject: Wanted satellite tracking program for GPS sats
Newsgroups: sci.space
Can anybody please tell me where I can get a satellite tracking program
suitable for use with NAVSTAR (Global Positioning System) satellites.
I'd prefer public domain/shareware etc, but I'm desperate enough
to buy a commercial product.
Iv'e looked at quite a few satellite tracking programs (SIMTEL 20
& Celestial BBS), but none present the data in the form convenient for
determining the observable satellites for GPS positioning purposes.
Basically, you need a tracking program that shows the azimuth and
elevation of all observable satellites at a particular time, so the
program must track 24 or so satellites. It would be nice if the
GDOP/HDOP were also calculated..
Preferably the program should use the standard Norad 2-Line elements.
Please don't e-mail me - incomming messages are broke!
