Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_286.TXT

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Subject: SPACE Digest V8 #286

SPACE Digest                                      Volume 8 : Issue 286

Today's Topics:
                time travel???
             Mail test for BITNET
             Mir and solar flares
               News test #2 for BITNET
               Ramscoop engine
                 Re: Pegasus
             Condensed CANOPUS - May 1988
            Re: NASA news - Seasat
----------------------------------------------------------------------

Date: 3 Jul 88 01:28:55 GMT
From: mind![e-mail]  (Shari Landes)
Subject: time travel???

(From my 12-yr old son, Harlan)

Is it possible that if you travel faster than the speed of light in space,
and come back to earth, you would be able to see yourself in the past?

I think it is possible because when you approach the speed of light, time slows
down, and if you travel the speed of light, time stops.
But, if you return to earth, after traveling in space faster than the speed
of light, would you be able to see yourself before you left?


-- Harlan


--
Shari Landes                    609-452-4663
Princeton Univ. Green Hall                      [e-mail]
Princeton NJ 08544              "Don't look back..."

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

Date: Tue, 5 Jul 88 11:39:13 PDT
From: Eugene N. Miya <[e-mail]>
Subject: Mail test for BITNET

Okay Argonne, ACK me if you get this.  This was sent using ARPAnet gateway.

--eugene

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

Date: Tue, 5 Jul 88 15:41:24 EDT
From: Glenn Chapman <[e-mail]>
Subject: Mir and solar flares

A rather interesting point concerning Mir was made by Bill Higgins of Fermi Lab
in a mail message to me.  He said:

> I encountered a brief headline about a "magnetic storm"  that's supposed
> to hit this planet this week and stopped to wonder-- what do the Mir & Salyut
> cosmonauts do when there's a solar flare?   Obviously they don't pack up
> and go home.  Is there a storm cellar arrangement aboard Mir?  Can you explain
> the details?

    He raises a good point about the solar flare.  There is no storm shelter on the Mir station.  However they are located in low earth orbit, below the
Van Allen belts.  This means that the earth's magnetic field protects them from
the proton particles of the flare.  The X-rays from that event I think are
rather soft so the station itself has enough mass that the cosmonauts are safe.
Never the less they are located at an orbit >70 degrees inclination.  That
starts putting them near to where stuff leaks through at the magnetic poles,
especially as flare tends to distort the magnetic field lines (note that the
North magnetic pole is located well within northern Canada - about 78 degrees
latitude).  I would suspect that would give them substantially higher
radiation levels than normal.  It is interesting that they went ahead with
the space walk under these conditions.
    Speaking of the EVA, Titov and Manarov on board Mir went out this morning
(June 30th) for 5 hours to try and fix the British/Dutch X-ray telescope on the
Kvant module.  The current information I have is either the repair did not work,
or was not finished.  They plan another EVA in a few days.  I will post more
when I get more information.
    Does anyone out there know what NASA does during similar flares for high
inclination shuttle orbits?   Hopefully this to will become an issue that
we are in space enough to consider.

                                                   Glenn Chapman
                                                   MIT Lincoln Lab

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

Date: 5 Jul 88 18:40:52 GMT
From: pioneer.arc.nasa.gov![e-mail]  (Eugene N. Miya)
Subject: News test #2 for BITNET

Okay Argonne ACK this.  Check the dates in the headers if you can.
This was posted to the Usenet side.

--eugene (Ted please let these thru)

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

Date: Tue, 05 Jul 88 12:19:36 CDT
From: [e-mail]
Subject: Ramscoop engine

   I've read in various places (Carl Sagan's COSMOS, among others) that a
ramscoop engine is possible.  For those of you who don't know what a ramscoop
is, it's essentially a big loose-hydrogen-nuclei collector that sweeps a pretty
big area clean of stray hydrogen nuclei, gathers them together into a real hot,
tightly packed stream, and fuses them.  The idea of this kind of engine is that
you can keep up a constant rate of acceleration/deceleration, without running
out of fuel.
   I've got a couple questions, for anyone out there that has the time and inte
rest to answer...
   1.)  How do you reverse the thrust in one?  It looks like you'd just alter
the scoop field so that the fusion would be blasting more forward than backward
, but I have a hard time visualizing a stable ship design for this.
   2.)  What do you do about micrometeorites, and, for that matter, big meteors
 in your path?
   3.)  How much energy does it take to maintain the field, and can you safely
keep getting that from the fusion reaction?  Especially since the ramscoops are
supposed to be for fairly long trips (100's of years!), how do you keep a power
system running that collects lots of energy from the reactor working for 100`s
of years, without any direct maintainance?  (Definitely no HUMAN maintainance!)
   4.)  What do you do when you're decelerating, and you fall below ramscoop
velocity?
   5.)  Does the density of stray hydrogen nuclei vary as much as it seems like
it would between different areas of space?  Is the density vastly thinner
far away from stars?  Is the density around the core different than the density
in the outer arms of the galaxy?  (Obviously, this might make a ramscoop's
bottom velocity lower in dense areas...)

   Well, thanks for whatever you can give me...

   John Kelsey == Fiver == [e-mail]

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

Date: 1 Jul 88 20:20:17 GMT
From: uplherc!esunix![e-mail]  (Bob Pendleton)
Subject: Re: Pegasus

From article <[e-mail]>, by [e-mail] (Phil R. Karn):
> Am I the only one who is amazed that anyone would give any credibility
> at all to the launch costs projected by the manufacturer of a radically
> new launcher that hasn't even been built yet, much less tested and made
> operational?

What is so radical about Pegasus? Air launch? We've been air launching
rockets for 40 years. Remember the X-1? The motors? Carbon filament
wound cases and solid propellant, not significantly different that MX
3rd stage. A wing? Come on. Hypersonic flight? Space Shuttle and other
vehicles have been doing it for years. Guidance system? Off the shelf.

Pegasus could have been built years ago if anyone had thought of it
or had reason to try.

> Or hasn't anyone learned from the Shuttle experience?

Yes they have. Pegasus is a conservative design, built by private
corporations with the goal of making money. Very different from the
Shuttle.

Now I hope they don't make a liar of me.

            Bob P.

--
Bob Pendleton @ Evans & Sutherland
UUCP Address:  {decvax,ucbvax,allegra}!decwrl!esunix!bpendlet
Alternate:     utah-cs!utah-gr!uplherc!esunix!bpendlet
        I am solely responsible for what I say.

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

Date: 5 Jul 88 19:36:30 GMT
From: cfa!cfa250![e-mail]  (Steve Willner P-316 x57123)
Subject: Condensed CANOPUS - May 1988

Here's the condensed CANOPUS for May 1988.  There are 9 articles.
Eight are given in condensed form and one by title only.  Comments in
{braces} are from me and are signed {--SW} when they represent
personal opinions.  The unabridged version went to the mailing list
weeks ago.  Sorry this is so late, but things have been pretty hectic
around here the last month.

CANOPUS is published by the American Institute of Aeronautics and
Astronautics.  Send correspondence about its contents to the executive
editor, William W. L. Taylor ([e-mail];
e-mail to [e-mail] will probably be forwarded).  Send
correspondence about business matters to Mr. John Newbauer, AIAA,
1633 Broadway, NY, NY 10019.  Although AIAA has copyrighted CANOPUS
and registered its name, you are encouraged to distribute CANOPUS
widely, either electronically or as printout copies.  If you do,
however, please send a brief message to Taylor estimating how many
others receive copies.  CANOPUS is partially supported by the
National Space Science Data Center.

SPACE SHUTTLE STILL LOOKING AT AUGUST LAUNCH - can880506.txt - 5/10/88
{Title only; shuttle news widely reported elsewhere.}

SMALL EXPLORER A.O. RELEASED - can880508.txt - 5/16/88

NASA has released its Announcement of Opportunity for the "Small-
Class Explorer Mission" series.  Perhaps because the program is
intended to develop small payloads in quick order, the 50-plus-page
A.O. is quite detailed and restrictive about what can and cannot be
done. This broad A.O. is to lead to launches of one or two "Scout-
class" Explorers year as budget allows over the next few years.  It
is open to astrophysics, space physics, and upper atmosphere
disciplines, and to proposers in industry, academia, government, and
foreign agencies.

The research will be "of modest programmatic scope which can be
launched within about three years of selection. The program intends
to provide a continuing opportunity for quickly implemented flights
of small free-flyers to conduct focused investigations which
complement major missions, prove new scientific concepts, or make
significant contributions to space science in other ways. It is the
goal of the program to obtain a flight frequency of at least one
flight per year. The scope of the missions is expected to be such
that a single principal investigator will have responsibility for an
individual investigation."  {Instigation of this program is a real
accomplishment for Lennard Fisk, Associate Administrator for Space
Science, who seems genuinely interested in flying missions and not
just running a bureaucracy.  Now let's hope he can keep the budget at
a level adequate to actually fly and not just build payloads.  --SW}

The new Scout-class category is defined as a spacecraft and
instrument payload costing about $30 million and capable of being
launched on a Scout expendable launch vehicle (ELV).  Payload mass
can vary depending of the orbit to be reached, but generally will be
between 100 and 250 kg.  Data will be relayed through ground stations
and not through the Tracking and Data Relay Satellite System because
of the cost of using the latter.  {So much for cost savings promised
for TDRSS. --SW}

SOVIET-AMERICAN COOPERATION IMPROVES - can880501.txt - 5/5/88

Cooperation between the Soviet and American space programs took a
major step forward this month with the meeting of two working groups
formed last year by an agreement between the two nations.  No
immediate plans were made for sharing hardware or placing one
nation's instruments aboard other's spacecraft -- that will not come
until the mid-1990s, the participants indicated -- but joint
campaigns are anticipated for existing and currently planned
spacecraft.  A key example would be stereo X-ray imaging of the solar
corona using instruments aboard the American Solar Maximum Mission
satellite and aboard the Soviet's Phobos Mars spacecraft that will be
launched next year.

Cooperation never halted completely, {i.e. after invasion of
Afghanistan} with life scientists still sharing data at the working
level, and one small U.S. instrument package being flown aboard the
Soviets' VEGA probes that flew past Venus and Halley's comet.

AO FOR ATTACHED PAYLOADS ON SPACE STATION DUE SOON - CAN880503.TXT -
5/8/888

The Announcement of Opportunity for payloads attached to the manned
Space Station should be issued by the National Aeronautics and Space
Administration by the end of the month if the remainder of the
preparation moves smoothly.  Not included in the AO will be payloads
for free-flyers (covered in large part by the Earth Observing System
AO early this year), or "quick is beautiful" payloads.  {As of July
5, I haven't seen the AO, but I may not be on that mailing list.--SW}

Two more major AO's are planned for space station -- materials
sciences in 1989 and life sciences in 1990. These will focus to a
large degree on using multi-purpose facilities that NASA will
provide.

AROUND THE WORLD IN A BALLOON - can880505.txt - 5/9/88

NASA is soliciting instruments to fly aboard six long-duration
balloon flights (LDBF) during the 1991 solar maximum period according
to a research announcement (NRA-88-OSAA-04) released May 6.  The
program is intended for instruments which cannot observe adequately
from the ground or during short-duration balloon or rocket flights,
and "which are expected to advance our understanding of the solar
energetic phenomena in a way that will not otherwise be possible
until the subsequent solar maximum in the year 2002."

Experimental LBDF flights to date have lasted 12 to 22 days going
around the globe, and 6 to 12 days going from Australia to South
America. Payloads can be up to 1,400 kg at altitudes to 40 km. Up to
8 to 12 hours of observations a day are possible.

SHUTTLE-C COULD HELP SPACE STATION - can880507.txt - 5/10/88

An unmanned cargo version of the Space Shuttle could cut several
months from the assembly time for Space Station by carrying more than
double the payload of the manned Shuttle, according to its study
manager.

Shuttle-C looks much the current Space Shuttle but for wings and
vertical stabilizer which are lacking, and windows on the forward
fuselage. It would use the same boosters and tank, and would carry
its cargo in a strongback sitting above an engine module identical to
the Shuttle's boattail section.

"CODE E" ADVISORY COMMITTEES TO MERGE - can880504.txt - 5/8/88

NASA's three science advisory committees will merge into a single
body with three branches this summer. {Committtees are:}
   o Life Science Advisory Committee,
   o Space and Earth Sciences Advisory Committee,
   o Space Applications Committee,

NASA DIRECTORY - can880502.txt - 5/8/88

NASA's main number is 202-453-1000. {Long list deleted; if enough
demand, I'll post the list separately.}

ASTRONAUT SELECTION GOES TO TWO-YEAR CYCLE - can880509.txt - 5/16/88

NASA will reopen the astronaut selection process starting July 1,
1989, for a "class" to be selected in January 1990, and will continue
selections every two years. This will ease the demands on NASA
resources for selection and training while maintaining flight crew
levels. NASA has selected astronauts in 1978, '80, '84, '85 and '87.
Applications may be obtained from:

     Astronaut Selection Office -- Code AHX
     Johnson Space Center
     Houston, TX 77058
--
Steve Willner            Phone [phone]         Bitnet:   willner@cfa
60 Garden St.            FTS:      830-7123           UUCP:   willner@cfa
Cambridge, MA 02138 USA                 Internet: [e-mail]

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

Date: 5 Jul 88 20:00:44 GMT
From: devvax!jplpro![e-mail]  (Lee Mellinger)
Subject: Re: NASA news - Seasat

In article <[e-mail]> [e-mail] writes:
|
|/* Written  2:45 pm  Jun 29, 1988 by [e-mail] in m.cs.uiuc.edu:sci.space */
|
|An aside on SeaSat 1 -- The satellite failed some time before the end
|of its expected service life.  A persistent rumor states that it was
|intentionally disabled, possibly by aiming sensors at the Sun; the
|purported explanation was that it was able to detect the wakes of
|ballistic-missile submarines.
|
|Kevin Kenny               UUCP: {ihnp4,pur-ee,convex}!uiucdcs!kenny

The investigation into the failure of Seasat assigned the probable
cause to a short across the slip rings that transfer the power
generated by the solar cells to the power buss where the solar panels
rotate.  They attributed this to the poor design of the slip rings
that had the various voltages (48 rings) alternating plus and minus,
creating the maximun potential to catastrophic electical short.  It
was shown  that there was a galling problem (in the ring bearings I
believe) that created metal slivers.  These slivers more than likely
shorted the main power buss at the rings. The telemetery showed large
voltage and current excursions in the milliseconds prior to loss of
signal from the spacecraft.

I too have heard unconfirmed rumors of the possibility that SSBM wakes
could be seen in the radar imaging data.  I was clear on the images
that I saw that surface wakes were very visible.

The spacecraft lasted only 90 days in a planned life of one year.  I
have had people tell me that they were not unhappy that the spacecraft
had shut down because of the enourmous quantity of data that was
pouring in.

Lee
.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
|Lee F. Mellinger                         Jet Propulsion Laboratory - NASA|
|4800 Oak Grove Drive, Pasadena, CA 91109 818/393-0516  FTS 977-0516      |
|-------------------------------------------------------------------------|
|UUCP: {ames!cit-vax,psivax}!elroy!jpl-devvax!jplpro!leem                 |
|ARPA: jplpro!leem!@cit-vax.ARPA -or- [e-mail]            |
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

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

End of SPACE Digest V8 #286
*******************