Grex Space Conference

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Grex Space Item 11: Asteroids - A hit or miss situation
Entered by jsw on Fri Sep 4 20:06:51 UTC 1998:

Based on the programs, movies, and news reports we should not make any 
longterm plans.  The biggest selling movie of the summer at $188 
million was Armageddon.  The public must be ready to spend on a really 
big search for the now famous Earth Crossing Asteroids.  Right now the 
Washington politicians are trying to buyoff the concern by providing a 
few million to search for the minimun number of Asteroids.  I think 
there could be money for a serious search and an ongoing observation 
program.  But how????

8 responses total.

#1 of 8 by gillmore on Fri Sep 25 16:09:21 1998:

Is anybody working on flingers--some device to accelerate packages to 
orbital speed and toss them into orbit from the ground?

#2 of 8 by dang on Sun Sep 27 20:45:06 1998:

I heard of one effort that uses a surplus defense laser to send a small,
unmanned package into space.  There is a specially shaped parabolic
mirror on the bottom, and the laser hits the mirror and ignites the air
underneath.  The, with repeated pulses, the package is accelerated. 
It's possible.  It works, sortof, for test models.

#3 of 8 by djvr on Sat Oct 3 20:16:27 1998:

there's no doubt that the asteroid danger is far from insignficant. All this
time we have been sitting unawares of what might come down from above all of
a sudden. Now, I'm from india so i don't really have much info about Congress
decisiions and all that stuff. What i feel is that we tend to underestimate
amateur astronomers a bit too much. A proper, concerted amateur programme
aimed toward finding NEA (Near Earth Asteroids) should be pretty useful in
maintaining a tally of these space critters, as well well as searching for
new ones.. The really dangerous asteroids, ones with radii approx. 5 km. +,
can be easily spotted by amateur scopes, if in NEA orbit, and amateurs
obvously have more time and energy than the professionals. besides , the cost
fo the whole project would come down too. What do you guys have to say?

#4 of 8 by rcurl on Sat Oct 3 21:19:43 1998:

Amateurs *have* discovered most of the NEA. There was an article about this,
and a larger planned professional search, in a recent issue of SCIENCE.

#5 of 8 by russ on Sat Oct 3 23:27:22 1998:

Re #0:  There is a big amateur effort to find near-earth asteroids.
I seem to recall that several new ones are found each month.  If
one (or several) are found heading for Earth, maybe the pols will
spend some money.  They'd want to claim credit for saving us, right?
 
Re #2:  That's the "propellant-free" model (which uses air, as long
as there is enough air).  There have also been designs which use ice
as the propellant, and vaporize a thin layer off the back of a lens-
shaped slab with each laser shot.  The expanding steam shoves the
rest of the package along.  Payload to orbit would be a few kilograms,
but for the investment in the laser and mirrors it could fling those
kilos into orbit every few minutes all day and all night.  Where a
Shuttle is a panel truck to space, this would be a skinny pipeline.
Over time, it would move a lot more than Shuttle and for lots less.
 
I suppose if you need to get food and propellant up to the astronauts
who are going to go to the Orion ship in its highly-elliptical orbit
(so you don't have to fire any bombs near Earth), it becomes attractive.
Unless someone can use the capacity of the pipeline, it's not.
 
Maybe this discussion needs its own item, and leave this one for NEAs.

#6 of 8 by russ on Mon Oct 12 00:34:05 1998:

I have entered Science item #39 about the physics of smoothing out
the bumps of pulse-fission drives.

#7 of 8 by kghose on Wed Apr 28 15:42:08 1999:

Rather than have a lot of money pumped into a (relatively) few expensive
government run sites to find NEA, why not set out a program that would
involve all the institutions across the globe having telescope
facilities
 
a) investing a part of viewing time to actively search for NEAs
b) run additional checks for NEAs on photos taken during regular
operation 

Then the relevant coordinates, sizes etc. could be e-mailed to a central
facility that automatically sorts out this and plots it on a chart or
something as a tentative NEA and tries to cross check it from other
reports. There are lots of details of course, but why not distributed
processing employing existing hardware instead of splurging on new
hardware ?

#8 of 8 by dang on Thu May 6 22:09:24 1999:

I'd guess that certian portions of the sky are much more interesting
than other, so large portions of the sky wouldn't get searched that
way.  In addition, much of the current telescope work is focused very
far away, and close objects like NEAs would even show up.  Have you ever
looked at something through binoculars that was on the other side of
relatively close bushes or tree branches?  The obscuring foliage is so
out of focus it almost doesn't show up.  NEAs are relatively much
smaller than the foliage, and so likely wouldn't show up at all.  That
said, the first option might work, if you could justify it to the
institutions.

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