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Subject: SPACE Digest V12 #482

SPACE Digest                                     Volume 12 : Issue 482

Today's Topics:
       Tentative Date for Launch of 10th GPS Block II Satellite
          GPS Satellite Constellation Status
      Planetary coordinates (was: Re: planetary north and names)
       Re: You Can't Expect a Space Station to be Cheap
                  HST Update

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

Date: Tue, 23 Oct 90 15:36:45 ADT
From: [e-mail]
Subject: Tentative Date for Launch of 10th GPS Block II Satellite
Apparently-To: <[e-mail]>

The tentative date for the launch of the 10th Navstar GPS Block II
satellite is 20 November 1990.  The satellite will be placed in orbit
from Cape Canaveral onboard a Delta-II booster.  A successful launch
will bring the total number of usable GPS satellites to 16.

(Source:  USNO)

================================================================================
 Richard B. Langley                            BITnet: [e-mail] or [e-mail]
 Geodetic Research Laboratory                  Phone:  [phone]
 Dept. of Surveying Engineering                Telex:  014-46202
 University of New Brunswick                   FAX:    [phone]
 Fredericton, N.B., Canada  E3B 5A3
================================================================================

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

Date: Tue, 23 Oct 90 15:18:18 ADT
From: [e-mail]
Subject: GPS Satellite Constellation Status
Apparently-To: <[e-mail]>


                        Navstar GPS Constellation Status
                                   (90-10-23)

Blk                       NASA   Orbit
II        PRN Internat. Catalog  Plane   Launch
Seq   SVN Code   ID      Number  Pos'n    Date   Clock        Comment
--------------------------------------------------------------------------------
Block I
       1   4  1978-020A  10684   (C-4)  78-02-22      Not usable since 85-07
       2   7  1978-047A  10893   (A-4)  78-05-13      Not usable since 85-09
       3   6  1978-093A  11054    A-3   78-10-06  Rb
       4   8  1978-112A  11141   (C-3)  78-12-10      L-band signals turned
                                                       off 89-10-14
       5   5  1980-011A  11690   (C-1)  80-02-09      Not usable since 84-05
       6   9  1980-032A  11783    A-2   80-04-26  Rb  Operating on 2nd Rb clock
       7                                81-12-18      Launch failure
       8  11  1983-072A  14189    C-2   83-07-14  Cs
       9  13  1984-059A  15039    C-1   84-06-13  Cs
      10  12  1984-097A  15271    A-1   84-09-08  Cs
      11   3  1985-093A  16129    D-1   85-10-09  Rb  Actually near position
                                                       C-9; operating on Rb
                                                       clock without temp.
                                                       control

Block II
II-1  14  14  1989-013A  19802    E-1   89-02-14  Cs  Became available 89-04-15
II-2  13   2  1989-044A  20061    B-3   89-06-10  Cs  Became available 89-08-10
II-3  16  16  1989-064A  20185    E-3   89-08-18  Rb  Became available 89-10-14
II-4  19  19  1989-085A  20302    A-4   89-10-21  Cs  Became available 89-11-23
II-5  17  17  1989-097A  20361    D-3   89-12-11  Cs  L-band signals enabled
                                                       90-01-06
II-6  18  18  1990-008A  20452    F-3   90-01-24  Cs  Became available 90-02-14
                                                       22:26 UT
II-7  20  20  1990-025A  20533    B-2   90-03-26  Cs  Became available 90-04-18
                                                       23:13 UT
II-8  21  21  1990-068A  20724    E-2   90-08-02  Cs  Became available 90-08-22
                                                       15:00 UT
II-9  15  15  1990-088A  20830    D-2   90-10-01  Cs  Became usable 90-10-15
                                                       00:39 UT

Notes
1.  NASA Catalog Number is also known as NORAD or U.S. Space Command object
    number.
2.  Bracketed orbital plane position = satellite no longer operational.
3.  An earlier version of this table had PRN 16 in plane D.  Note correction.
4.  Clock:  Rb = Rubidium; Cs = Cesium
5.  A series of maneouvres to rephase the Block I and II satellites began on 15
    March 1990.  PRNs 2, 11, 14, 18, and 19 are still drifting to their
    final in-plane locations.
6.  The orbit plane slots given for the Block I satellites are those positions
    before the current maneouvres.

================================================================================
 Richard B. Langley                            BITnet: [e-mail] or [e-mail]
 Geodetic Research Laboratory                  Phone:  [phone]
 Dept. of Surveying Engineering                Telex:  014-46202
 University of New Brunswick                   FAX:    [phone]
 Fredericton, N.B., Canada  E3B 5A3
================================================================================

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

Date:     Tue, 23 Oct 90 10:57 CST
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject:  Planetary coordinates (was: Re: planetary north and names)
Original_To:  SPACE

Different  celestial  bodies  have  different   systems   for
designating  latitude  and longitude.  On the Moon, latitude and
longitude follow a system much like  the  Earth's:  Latitude  is
measured as degrees north or south of the equator.  Longitude is
measured as degrees east or west of a prime meridian,  so  that the
maximum value it can have is 180 degrees East or 180 degrees West.
The prime meridian passes through the mean sub-Earth point, I believe.

On Mars and other bodies,  all  longitudes  are  measured  in degrees
west of the prime meridian, so they range from 0 to 360. No "East" or
"West"  designation  is  necessary.   For  example, instead  of  being
roughly  at  90  degrees  East,  the city of Calcutta would be at "270
degrees" instead in such a system.

This information comes from my reading of maps.  How did space
cartography get this way?  Beats me.  Moon maps, Mars maps, and
Venus-and-everywhere-else maps were presumably started in different
centuries, which probably had some influence on their evolution.
Pointers to more information would be welcome.

During the first and second stage         Bill Higgins
flights of the vehicle, if a serious      Fermi National Accelerator Laboratory
irretrievable fault should occur and      [e-mail]
the deviation of the flight attitude of   [e-mail]
the vehicle exceeds a predetermined       SPAN/Hepnet: 43011::HIGGINS
value, the attitude self-destruction
system will make the vehicle
self-destroyed.
     --Long March 3 User's Manual
     Ministry of Astronautics, People's Republic of China (1985)

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

Date: Tue, 23 Oct 90 22:06:42 -0400
From: "Allen W. Sherzer" <[e-mail]>
Subject: Re: You Can't Expect a Space Station to be Cheap
Newsgroups: sci.space
Cc:

In article <[e-mail]>:
>As a designer on Fred who is only superficially familiar with the LLNL
>ideas, let me throw out some of the major design drivers on Fred, and I
>would like to know how LLNL deals with them.....

I'll do my best to answer although I don't have all the details. If you
still have questions I would encourage you to research the program yourself.
I can give you some references and addresses.

>1 - Atomic oxygen, very few materials can survive thirty years in the AO
>environment, Fred has a 30 year lifetime requirement.   That means we have
>to GUARANTEE 30 years, in reality it might last much longer;  what material
>is the inflatable habitat made of ?  Exterior surfaces must all be metallic
>to shield against AO, does the LLNL design do this ?

The LLNL Earth station outer layer is PTFE-overcoated Kevlar. They are
designed to deal with vacume and temprature. ILC, the company which
has built all NASA space suits since Apollo has done a preliminary
design and say it will work [1]. As for atomic oxygen, PTFE has exibited
surface erosion when exposed to atomic O2 of less than 3 microns/year [2]
so a coating 100 microns deep will do.

I should also add that the LLNL station is designed for a life of ten
years not thirty. But since it costs less than 5% of what Freedom costs
this shouldn't be viewed as a problem.

>2 - Radiation - need to guarantee to operate after a 30 year dose in LEO
>(crews rotated every 90 days) kinda restricts the electrical design;

My sources do not say anything on this for the Earth Station, just for
the trip to Mars. However, in my readings of NASA objections to the
Great Exploration they make no mention of it. It could be that LLNL
presented an approach NASA accepted.

What special steps is Freedom taking?

>3 - orbital debris - need to have a Safe Haven configuration of multiple
>interconnected nodes and modules with fast closing hatches in between, to
>seal off the punctured section, can the LLNL design do this ?

Yes, for details, see [1]. The Earth Station has an external shield
plus 24 spearate airtight compartments.

BTW, can Freedom do the same? From what I have seen the two main
modules are all open. What would the Freedom crew do if there was
a large breach in the main habitation module?

>4 - Can LLNL assemble their Fred equivalent system using 22 shuttle
>flights?   This means weight is a big issue.

The LLNL Earth Station goes up in 1 HLV flight. This can be done because
the inflatable structures greatly reduce weight and launch volume. In
[1], ILC states that the packed volume of the Earth Station would be
28.8 cubic meters for an all fabric design and 31.6 cubic meters for
a design with hard pressure bearing floors. The total weight budget
is 40.4 tons, but that includes everything.

>LLNL's amorphous silicon
>solar cells are certainly cheap to manufacture, but  for watts per pound
>they are inferior, and heavy to launch.

They are claiming 1KW per kilo of silicon. NASA says that is an order of
magnitude better than the state of the art. (Dr. Wood provided them with
samples). Either way, this is a minor issue. The weight budget for power
is big enough to use what NASA says is the state of the art.

>5 - LLNL's Nickel-hydrogen batteries are nothing new, Fred uses the same
>type;

Interesting. The NASA assessment says these batteries won't work [3].
Why is Freedom using batteries which NASA says won't work? If they
will work, why is NASA saying they won't?

>6 - What experience does LLNL have in the following areas of space
>applications:- airlocks, hyperbaric chambers, long life vacuum bearings,
>BAPTAS (Bearing and Power Transfer Assemblies) = slip rings to get power
>and data from the rotating panels to the station users,  large space
>structures attitude control, long life propulsion systems, low pressure
>outgassing and offgassing;

Don't know in detail (why don't you call and ask?). They have however,
done work in space based systems and have experience running large
complex technical programs.

>The impression I have is that LNNL trades off safety and risk versus cost.

And who doesn't? The only way for Freedom to avoid those trade offs
is to not build it.

>As a safety engineer that is anathema to me.

As a safety engineer it is your job to quantify exactly that. Tell me
something, as a safety engineer on Freedom what are the odds of a
death due to a major breach of the habitation module?

>There is nothing clever
>about taking risks, any fool can do that.

That implies that the people flying on Freedom are either not taking any
risks or are fools.

Yes this program is risky. It is about as risky as Apollo. The Earth
Station however, has an assured crew return vehicle as part of its design
so although the odds of a major failure are high, the odds of loss of
crew are much lower.

>However, they better be
>prepared for the bad press they get when they have a Challenger style
>disaster.

They are. They are preparing by being up front with the risks involved.
Challenger was a disaster because people felt betrayed. NASA told them
the system was safe enough to send a school teacher. Had they been
more honest Challenger wouldn't have been so big a deal.

>    NASA clearly does not want anything like that to happen again, and
>safety costs money guys, sorry but that is just the facts of life.

NASA levels of safety will cost us half a trillion dollars to get to
Mars. We can't affoard that.

Exploration has always been very risky, there is no way around that.
Dynamic research and exploratory organizations thrive on this risk and
look forward to pushing the envelope. That spirit prevaded NASA
during Apollo. I don't think that spirit is dead, but it is dying.

    Allen


[1] Conceptual Design Study for Modular Inflatable Space Structure by
    ILC Dover inc. Dec. 4 1989 (LLNL Purchase order B098747)

[2] High Power Inflatable Radiator for Thermal Rejection From Space
    Power Systems by D. Chittenden, Pro23 Intersociety Energy Conversion
    Engineering Conference, 1988

[3] NASA Assessment of the LLNL Space Exploration Proposal and LLNL
    Responses, LLNL doc. no. SS90-9 page 27.
--
+-------------------------------------------------------------------------+
| Allen W. Sherzer      |         What should man do but dare?            |
|   [e-mail]         |             - Sir Gawain                        |
+-------------------------------------------------------------------------+

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

Date: Tue, 23 Oct 90 11:19:20 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: HST Update


There was a very interesting update on the Hubble Space Telescope on
NASA Select on Monday. Among other things, they described the uproar
following the discovery of the spherical aberration, from the viewpoint of
some of the people within NASA. I found it refreshingly candid, especially
the descriptions of the misunderstandings and exaggerations that arose.
For instance, they mentioned that one member of Congress gave an impassioned
speech on "ultraviolet light is invisible, so what good are pictures taken
in ultraviolet?".

While NASA is not blameless in this situation, I think they got a lot more
heat than the problem deserved. It seems in the past few months that the press
has been trying to give a fairer presentation of the facts.

There was considerable discussion of space science and future plans. I'll
try to post some details tonight.
      John Roberts
      [e-mail]

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

End of SPACE Digest V12 #482
*******************