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Date: Wed, 17 Apr 91 02:25:30 -0400 (EDT)
Subject: SPACE Digest V13 #417

SPACE Digest                                     Volume 13 : Issue 417

Today's Topics:
		 Re: Questions about pioneer/Voyager
	     Re: "Bussard Ramjets" AKA duct space drives

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Date: 15 Apr 91 22:38:42 GMT
From: csus.edu!wuarchive!usc!samsung!spool.mu.edu!cs.umn.edu!kksys!wd0gol!newave!john@ucdavis.ucdavis.edu  (John A. Weeks III)
Subject: Re: Questions about pioneer/Voyager

In article <1991Apr14.180423.29686@kuhub.cc.ukans.edu> utagikar@kuhub.cc.ukans.edu writes:
> I have always wondered about the space crafts Pioneer/Voyager etc
> 1) How was the collision with astroid belts avoided?

These are not "belts" as such, but rather zones or areas in space were
debris is somewhat more dense compared with surrounding areas.  A random
staight line path through the astroid belt will have a very low probability
of encountering an astroid.  Since the orbits of most larger astriods are 
known, one could reduce this probability even further.

> 2) How were/are they powered? If with nuclear power; how come NASA
> doesn't quote its sucess to the people demonstrating against nuclear
> powered crafts?

The space craft were launched with chemical rockets, and received futher
boosts from planetary fly-bys.  Electricity on the space craft was provided
by nuclear generators.  The heat of the nuclear material was converted into
electric energy--there were no reators (in the conventional nuclear/steam
power plant sense).

NASA does point to the sucess of nuclear power in the Apollo, Voyager,
and other programs, but this does not deter the nuclear skeptics.  Witness
the outcry from the Christic Institute when Galileo was launched.

BTW, there have been nuclear accidents associated with space craft.  I
recall a Soviet sattelite that reentered and contaminated a small area in
Canada.  The USA currently does not use nuclear reators in space, that I
am aware of.  There is also an RTG (radioactive thermonic generator) from
the Apollo 13 mission lunar module sitting on the bottom of the Pacific ocean.
It was never intended to come back to Earth, rather it was a side effect of
using the LEM as a life raft to bring the Apollo 13 crew back after the
explosion in the service module.

> 3) People who must have watched "First Contact" the episode in
> Star Trek The Next Gen might recollect the government making the
> decision on whether to disclose the contact.. Now considering Earth
> with many different countries/governments, who made the decisions on
> revealing our presence and technological prowess? Was that a global
> decision? And if there is a contact who will make the decision on 
> whether to or not to tell the people?

It is made on an individual basis.  Earth is leaking radiation in the
form of communications transmissions (radio & tv, among others), and
has been for years.  I doubt that an alien would find a very small
space probe in the remote area of the solar system before it detected
the radio signals from Earth.

If there is contact, the decision will probably land on the whim of
whoever is involved in the contact.  This issue was addressed by the SETI
people (Search of ExtraTerrestrial Intelligence).  They have an agreement
to notify certain people and agencies in a particular order, and the UN
is involved somewhere in this chain.  Some argue that this contact has
already been made (the MJ-12 people and various other UFO and conspiracy
fans).

My question about the "First Contact" episode is how could a sufficiently
aware culture not notice a ship the size of the Enterprise in orbit.
Wouldn't it block out the thier sun or be visible at night by astronomers
(professional or amature)?  There has never been mention of the Enterprise
having a cloaking device.  Oh well....

-john-

-- 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
John A. Weeks III               (612) 942-6969             john@newave.mn.org
NeWave Communications                       ...uunet!tcnet!wd0gol!newave!john

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Date: 15 Apr 91 22:46:17 GMT
From: agate!bionet!uwm.edu!spool.mu.edu!cs.umn.edu!kksys!wd0gol!newave!john@ucbvax.Berkeley.EDU  (John A. Weeks III)
Subject: Re: "Bussard Ramjets" AKA duct space drives

In article <41157@netnews.upenn.edu> sadinoff@eniac.seas.upenn.edu (Daniel Sadinoff) writes:
> 2) Assuming the thing travels at significant fractions of lightspeed,
> the impacts of the individual hydrogen (atoms? molecules?) become a
> design obstacle.  Is it possible to make a scoop out of an E-M field to
> gather the fuel so as to avoid this obstacle?

You better hope that you either have a uniform distribution of hydrogen,
or you have some way to predict the density.  Consider what would happen
if the hydrogen density suddenly increased and your engine was not expecting
it.  You would end up with either a power surge or a "major malfunction".

-john-

-- 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
John A. Weeks III               (612) 942-6969             john@newave.mn.org
NeWave Communications                       ...uunet!tcnet!wd0gol!newave!john

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End of SPACE Digest V13 #417
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