Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_5/V11_560.TXT

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Subject: SPACE Digest V11 #560

SPACE Digest                                     Volume 11 : Issue 560

Today's Topics:
         Re: Aim For The Moon - model rocket contest
               Satellite round-trip...
             Re: Satellite round-trip...
             Re: Satellite round-trip...
         Re: Aim for the Moon - Model Rocket contest
               Re: 10 psi overpressure
        Handicaped in Space (was: NASA Headline News)
               Re: 10 psi overpressure
              Re: HST crazy idea
         Re: Aim For The Moon - model rocket contest
         Re: Aim For The Moon - model rocket contest
            Re: Public Perception Of Space

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: 21 Jun 90 12:52:57 GMT
From: mcsun!ukc!edcastle![e-mail]  (A J Cunningham)
Subject: Re: Aim For The Moon - model rocket contest


    Given the current concern over the amount of debris already in
earth orbit shouldn't people be giving some consideration to what
happens to the payload after launch? Obviously the orbit will decay and
the payload will re-enter but after how long?
        Tony
--
Tony Cunningham, Edinburgh University Computing Service. [e-mail]

    Yuppies think I'm a wino 'cos I seem to have no class,
    Girls think I'm perverted 'cos I watch them as they pass.

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

Date: 22 Jun 90 10:03:22 GMT
From: [e-mail]
Subject: Satellite round-trip...

Was there ever a satellite designed to make a close pass by some inner planet,
or perhaps the sun itself, and rendezvous with the earth again elsewhere in
time and space so that it could be retrieved and studied for effects (whatever
effects they may wish to look for ).  Seems like an interesting idea to me.
How practical it would be, I don't know.

Also... has anyone heard about the mysterious circles appearing in the fields
of farmers in England, with no scientific explanation available?  These are
PERFECT circles, by the way.  Not something that could occur by any natural
means, and there are NEVER signs of any sort of human activity.  Witnesses
usually claim seeing bright orange lights and hearing whining noises.
Scientists are starting to get VERY serious about these things recently.  It
was on the CNN World Report yesterday.  It made me start thinking... are we
REALLY ready for extra-terrestrial contact?

What are YOUR opinions??

Mark C. Lowe - KB5III

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

Date: 22 Jun 90 13:03:27 GMT
From: usc!samsung!xylogics!world!ksr![e-mail]  (Chris Jones)
Subject: Re: Satellite round-trip...

In article <[e-mail]>, rdw2030@venus writes:
>Was there ever a satellite designed to make a close pass by some inner planet,
>or perhaps the sun itself, and rendezvous with the earth again elsewhere in
>time and space so that it could be retrieved and studied for effects (whatever
>effects they may wish to look for ).  Seems like an interesting idea to me.
>How practical it would be, I don't know.

No, not yet.  Unless it's planned as part of the mission, it would be
serendipity for a probe to pass close to the gravity well of a planet and
thence to earth.  Unless you intend to grab a probe which is moving at a
substantial relative rate to the earth when it returns, you have to have the
fuel on board said probe to reorbit the earth, and that's a penalty not really
worth paying.  (Still, I believe I recall that the International Comet Explorer
would be near earth sometime next century, and someone said we should go get
it.  Also, I'm sure Galileo could reorbit earth, though I'm sure they have
other plans for it(!)).

>Also... has anyone heard about the mysterious circles appearing in the fields
>of farmers in England, with no scientific explanation available?  These are
>PERFECT circles, by the way.  Not something that could occur by any natural
>means, and there are NEVER signs of any sort of human activity.

Ahem.  What do you mean by "perfect" circles?  I recall hearing about these
things, and I've seen no reason to believe they were neither natural nor of
human origin.

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

Date: 22 Jun 90 14:34:23 GMT
From: usc!cs.utexas.edu!titan![e-mail]  (Donald Heskett)
Subject: Re: Satellite round-trip...

I believe there is a UFO-oriented newsgroup.  I believe that is where
discussions of UFOs should occur.

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

Date: 22 Jun 90 15:36:04 GMT
From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Aim for the Moon - Model Rocket contest

In article <[e-mail]> [e-mail] (Glenn Read) writes:
>>The FAA is not in charge of this.  You need a license from the
>>Dept. of Transporation's Office of Commercial Space Transporation.
>>The regulations are very complex, you will need a lawyer, and the
>>cost of the license will [be high]
>
> Would this apply if you were to launch offshore - I remember something
> about a group using  a barge  type platform towed offshore to launch a
> quite  large  vehicle.  They had  some big bucks backing them and  the
> senior technical people were ex NASA.

Offshore launches have been considered for other reasons, notably range-
safety issues and alleged lower cost.  It would not exempt you from OCST
regulations.  The US government claims authority over its citizens anywhere
in the world (e.g., you are liable for US income tax for income earned
anywhere, although there are often reciprocal tax treaties that mitigate
this).  They probably wouldn't push this for foreign launches that
happened to involve US personnel, but for offshore launches specifically
intended to evade US regulation, I'd bet you'd find the Feds waiting when
you came back (or before you set out).
--
As a user I'll take speed over|     Henry Spencer at U of Toronto Zoology
features any day. -A.Tanenbaum| uunet!attcan!utzoo!henry [e-mail]

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

Date: 22 Jun 90 15:31:34 GMT
From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: 10 psi overpressure

In article <[e-mail]> [e-mail] (Ralph Reid) writes:
>As I remember, at some point a signal was sent to blow up what
>remained of the shuttle to keep large pieces from falling into
>populated areas.  No doubt this contributed to the ultimate
>destruction, although the shuttle may have been in several pieces by
>the time the destruct signal was sent.

The orbiter was already in pieces, and in any case does not carry a
destruct charge.  The external tank does have a destruct system, but it
was already so thoroughly shredded that the system did not function --
the E.T. destruct charges were recovered intact during the salvage work.
(Special priority was put on this because of the outside chance that
the accident had been caused by them firing.)  The destruct signal was
sent to keep the SRBs from running wild, and it succeeded at that, since
their destruct systems functioned.

Incidentally, there is a popular myth that the purpose of destruct charges
is to break up large pieces.  Not so; large pieces can hit the ocean as
hard as they want without causing any problems, and guaranteeing to shred
the whole rocket is very difficult.  The purpose of destruct systems is
to absolutely and positively terminate rocket thrust, so that the pieces,
large and small, will follow predictable paths.  The launch trajectories
are already chosen so that there are no populated areas under them (well,
until fairly late in the flight); the destruct systems are the ultimate
guarantee that the rocket will not go sufficiently far off the planned
trajectory to drop debris on bystanders.
--
As a user I'll take speed over|     Henry Spencer at U of Toronto Zoology
features any day. -A.Tanenbaum| uunet!attcan!utzoo!henry [e-mail]

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

Date: 22 Jun 90 22:04:36 GMT
From: usc!oberon.usc.edu![e-mail]  (Steve Robiner)
Subject: Handicaped in Space (was: NASA Headline News)

In article <[e-mail]> [e-mail] (Peter E. Yee) writes:

>keep muscles and bones healthy in space.  Dr. Peter Cavanagh will
>head a 3-year NASA study to examine how impact forces can be
>applied to astronauts' feet and legs during prolonged space
                        ^^^^^^^^^^^^^
>flight in order to counteract hypokinetic osteoporosis.  A
>weightlessness simulator will suspend a subject on a "wall-tread
>mill" supported by a system of elastic bunjy-like cords with
>force-measuring devices.  Researchers expect it to be up and
>running this August.
>                            ********

Has NASA or anyone else ever thought of using amputees or other naturally
handicaped persons with no legs as astronauts for extended stays in space.

It seems to me they'd be the ideal choice for the job.  While other
astronauts are handicaped in space *with* legs, persons without these appendages
who are normally handicaped on Earth would be free and easily mobile in space.
Furthermore, their overall weight would be somewhat less, reducing launch
payloads, and they wouldn't require any specialized exercise equiment
which also adds cost, development time, more launch weight, space on the ship,
and time out of the work schedule.

Also, I'm sure there are plenty of air force and navy veterns who
are already flight trained and maybe even some as test pilots, a NASA
favorite.

=steve=

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

Date: 22 Jun 90 23:25:00 GMT
From: swrinde!zaphod.mps.ohio-state.edu!samsung!crackers!cpoint!frog![e-mail]  (John Woods)
Subject: Re: 10 psi overpressure

In article <[e-mail]>, [e-mail] (Carl Gooch) writes:
> As I recall from a recent skim of the Rogers' Commission report,

Close, but no cigar.  Skim it again, in particular page 21:
"   At about 72.20 seconds the lower strut linking the Solid Rocket Booster
and the External Tank was severed or pulled away from the weakened hydrogen
tank permitting the right Solid Rocket Booster to rotate around the upper
attachment strut.  This rotation is indicated by divergent yaw and pitch rates
between the left and right Solid Rocket Boosters.
    At 73.124 seconds, a circumferential white vapor pattern was observed
blooming from the side of the External Tank bottom dome.  This was the
beginning of the structural failure of the hydrogen tank that culminated in
the entire aft dome dropping away.  This released massive amounts of liquid
hydrogen from the tank and created a sudden forward thrust of about
2.8 million pounds[1], pushing the hydrogen tank upward into the intertank
structure.  At about the same time, the rotating right Solid Rocket Booster
impacted the intertank structure and the lower part of the liquid oxygen tank.
These structures failed at 73.137 seconds as evidenced by the white vapors
appearing in the intertank region.
    Within milliseconds there was massive, almost explosive, burning of the
hydrogen streaming from the failed tank bottom and the liquid oxygen breach
in the area of the intertank.
    At this point in its trajectory, while traveling at a Mach number of
1.92 at an altitude of 46,000 feet, the Challenger was totally enveloped
in the explosive burn.  The Challenger's reaction control system ruptured
and a hypergolic burn of its propellants occurred as it exited the oxygen-
hydrogen flames.  The reddish brown colors of the hypergolic fuel burn are
visible on the edge of the main fireball.  The Orbiter, under severe
aerodynamic loads[2], broke into several large sections which emerged
from the fireball. ..."

My notes:
[1]  Note that the hydrogen was not burning (yet).  Think of those little
toy rockets that you half-fill with water and then pressurize with air...
[2]  Remember that Mach 1.92 number; think of little gremlins throwing
BIG sledgehammers at the Shuttle at this point...

> >told me (whether it is correct or not) that the main engines may have
> >been throttled up to 104% of capacity (this is a normal condition for
> >the main engines during launch) before the max-q point was reached.
> I don't know, but I doubt it.  They throttle down to 65% for max-q,
> and I don't recall any mention to the contrary in the report.

T+19.859s  SSME 94% Command
T+21.124s  Roll maneuver completed
T+35.769s  SSME 65% Command
T+36.990s  Roll and Yaw Attitude Response to Wind (36.990 to 62.990 sec)
T+51.860s  SSME 104% Command
T+58.788s  First evidence of flame on RH SRM
T+59.262s  Reconstructed Max Q (720 psf)

They don't make any mention of how fast the engines can spool up, nor do
they comment that the engines went to 104% early.  Before you proclaim that
the second to last entry there as evidence that it was the pressure,
remember:

T+ 0.678s  Confirmed smoke above field joint on RH SRM

--
John Woods, Charles River Data Systems, Framingham MA, [phone]
...!decvax!frog!john, [e-mail], ...!mit-eddie!jfw, [e-mail]

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

Date: 22 Jun 90 02:47:05 GMT
From: uoft02.utoledo.edu![e-mail]
Subject: Re: HST crazy idea

In article <[e-mail]>, [e-mail] (Cookson) writes:
>
> If it was in a higher orbit, keeping it lined up with Hubble and the sun
> would be a problem, as they would rotate at different speeds.  How about
> putting Hubble in a porlar orbit that follows the terminator,  that way it
> would always be in sunlight.
>
>

It would have to be relaunched to get it there and then you would have to
work out some way to adjust the longitude so that it would remain
in this orientation as the earth went around the sun.  I would have to
brush up on my orbital mechanics to see if this is possible.

Robert Dempsey
Ritter Observatory

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

Date: 22 Jun 90 06:04:44 GMT
From: zaphod.mps.ohio-state.edu!sdd.hp.com!elroy.jpl.nasa.gov!jarthur!nntp-server.caltech.edu!arrester![e-mail]  (David Palmer)
Subject: Re: Aim For The Moon - model rocket contest

Three suggestions for hitting the moon:

    Handle aspect sensing (which way are we pointing?) with a sun
sensor.  Easy to make: just a cross of cardboard and 4 photodetectors
gives an error signal for adjusting the pointing.  Launch at dawn
to get the eastward component.  Launch at the right phase of the moon
so that the moon will be there when the rocket gets there.  Guidance
problem is solved.

    Launch from a weather balloon.  Going up even 50,000 feet
gets above a lot of the atmosphere.  For a small rocket, the balloon
doesn't have to be big.  Hang the rocket horizontally (tilting slightly upward)
and have it fire when the atmosphereic pressure is low enough AND
it is pointing in the right direction as determined
by the sun sensor.

    Launch from outside the US, maybe in international waters,
near the equator.  Saves a hell of a lot of money on legal fees.

    Good luck.

--
        David Palmer
        [e-mail]
        ...rutgers!cit-vax!gap.cco.caltech.edu!palmer
    I have the power to cloud men's minds -- or at least my own.

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

Date: 21 Jun 90 19:26:15 GMT
From: sam.cs.cmu.edu![e-mail]  (Vincent Cate)
Subject: Re: Aim For The Moon - model rocket contest



I have an idea for raising money that I really like.  The idea is to make
a sort of "space-athon".  You get all of the people who are participating
to go around door to door getting people to pledge money for every rocket
that gets near the moon (within 100,000 miles).  People could pledge
10 cents per rocket or $1 per rocket or whatever.  If we could get the
equivalent of 10,000 people pledging $1 per rocket, then all of the rockets
that flew well should get enough prize money to more than pay back their
rocket club's expenses.

I would be willing to pledge at least $1 per rocket and I think that
with a little effort at least 9,999 other such people could be found.

This would just be for a "completion prize".  There would be other
prizes as well.  Also, people could still sponsor a rocket directly.

One nice thing about the completion prize is that different groups would be
able to work together and share ideas without worrying about loosing this
prize money.

What do you think?  Would you pay $1 per rocket that made it?
Send email pledges to:

                  [e-mail]


   -- Vince

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

Date: 22 Jun 90 23:09:01 GMT
From: amdahl!rtech!beaver![e-mail]  (Steve Brooks)
Subject: Re: Public Perception Of Space

In article <[e-mail]> [e-mail] (Jon C. Slenk) writes:
>I belive that it is wrong for governments to step in and use their money
>to do what is *NOT ECONOMICALLY FEASABLE.* Note that it is not economically
>feasable BECAUSE PEOPLE AREN'T WILLING TO PAY FOR IT: that is the hypothesis

>So. No matter how one may look at it, I still don't belive that the US
>government, not any other government, should be "Out There" for any
>reasons other than strictly military ones.

How are the military reasons economically feasible ??

=====
SjB.

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

End of SPACE Digest V11 #560
*******************