Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_9/V16NO923.TXT

Text File | 1993-08-03 | 17KB | 420 lines

Space Digest                Mon, 26 Jul 93       Volume 16 : Issue 923

Today's Topics:
                        A ride to mir for onl
                      COOKIE CUUTTER PROBES (WA
                       DC-X thermal protection
               Found your own dark-sky nation? (2 msgs)
                  GPS in space (was Re: DC-1 & BDB)
                           Space Movie/PR..
            Test Stands at MSFC (Was Re: Room in the VAB?)
              Waste Management aboard Skylab and Shuttle

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

Date: 26 Jul 1993 07:16:07 GMT
From: Josh Hopkins <[e-mail]>
Subject: A ride to mir for onl
Newsgroups: sci.space

[e-mail] (Charles Radley) writes:


> -=> Quoting Johnwl to All <=-

> Jo> man in space last night. At one point the figure of $12 million was
> Jo> stated as the "commercial" cost the soviets were asking to put a man
> Jo> into Mir. This cost seems very low. If try, I could imagine many
> Jo> millionares might be willing to plunk down this money for the ride of a
> Jo> lifetime! I have some questions, however:
>
>All the guest cosmonauts take about six months of training.
>Russia also seems to have some kind of policy restricting flights
>to guests who have a scientific purpose.   Singer John Denver
>wanted to fly to Mir, but I hear he was refused because his
>flight would have no scientific content.

No, Both the Japanese and British passengers were essentially tourists.
John Denver (and others, he's just the most famous) didn't fly because he
didn't want to pay $12 million.

--
Josh Hopkins                                          [e-mail]
     "Physics is like sex: sure, it may give some practical results,
                 but that's not why we do it."
            -R. Feynman

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

Date: 26 Jul 1993 05:39:33 GMT
From: Josh Hopkins <[e-mail]>
Subject: COOKIE CUUTTER PROBES (WA
Newsgroups: sci.space

[e-mail] (Pat) writes:

>[e-mail] (Zvi Lev) writes:
>|A. It uses a new, totally non standard microprocessor.

>No longer true.  Standard processors  are far superior
>to NASA designed processors, and many of them are
>available in space qualified,  rad hard packages.

The main computers on Space Station Freedom (I can't think of the TLA for the
darn thing) are essentially 386 processors.

>|B. It has to have redundancy of all major units in hardware.

>|C. It has to have software which will support all these redundancies
>|autonomously.
>Now a solved problem. 20 years ago, it was serious,
>but now its simple.

Moreover, spacecraft are not entirely autonomous.  Many of them encounter a
serious problem and the software simply has to get things into a safemode and
wait for ground control to fix things.

>|D. It has to have a total mission reliability of more than 90% for a
>|period of about 1 year.
>Tandem beats that.

>|E. (that's the catch!) While the software and hardware can be
>|tested on a board by board basis and on simulatiors such as ICE  and other
>|debuggers, you CANNOT ever test the fully built system with the
>|actualy work enviro and the acutal inputs/outputs

If we could simulate the actual work environment and input perfectly we wouldn't
need to actually _do_ it would we?  The example I'm most familiar with is the
DMSOS, the OS for the Data Management System on Freedom.  It's based on a
COTS Unix clone, albeit rather heavily modified, and thoroughly tested on the
ground.  Every known bug has multiple pages of documentation.
not so much the testing as the modificiation that results.  The DMSOS or
shuttle software may not have been used as frequently as DOS or Windows but I
promise you it has fewer outstanding bugs.  Of course, the DMSOS isn't
finished, or if it is it's politically finished.

>>Now you may wonder what will be the unit price - ...
>>
>>Oh, and if I forgot to add to the price, the thing has to be operated for
>>a long time using complex machinery that is entirely not standard and by
>>very specialized personnel. Hmm....
>>

>A cheap probe can be operated by cheap personnell.

>I see no reason why Unviersity of Wisconsin or Illinois
>couldn't fly cheap probes,  especially  in earth observations
>or lunar science.

There is of course, Dennis at UAH.  The U of I does not have any active
satellite contracts at this time.  Funding is tight in many state schools right
now, and at the moment I'm not aware of anyone with the time and energy to
do what Dennis is doing.  It is not easy.  I wouldn't be surprised if we have
some flight hardware in the works for something else though.

>>Actually, it is even worse - I do not believe that the software
>>of any spacecraft is anywhere as reliable as that of any old (5 years),
>>popular PC operating system. No matter how clever the people who test it
>>are, they are not cleverer than 10^7 users with crazy setups and uses.
>>The same for hardware, of course...

The question is how frequently the software is corrected, not tested. The DMSOS
or shuttle software may not have been used as frequently as DOS or Windows but I
promise you it has fewer outstanding bugs.  Of course, the DMSOS isn't
finished, unless it's been abandoned.

Perhaps I should use this sig today:

Josh Hopkins                                          [e-mail]

  Program  pro'gram n.  An algorithm for converting input to error messages

--
Josh Hopkins                                          [e-mail]
     "Physics is like sex: sure, it may give some practical results,
                 but that's not why we do it."
            -R. Feynman

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

Date: 26 Jul 1993 06:45:07 GMT
From: Josh Hopkins <[e-mail]>
Subject: DC-X thermal protection
Newsgroups: sci.space

[e-mail] (Allen W. Sherzer) writes:

>In article <22cbfr$[e-mail]> [e-mail] (Pat) writes:

>>Is this the remnant of the silly USAF requirement
>>that the STS be able to  fly  1,800 miles cross range.

>It's not a silly requirement if you want to fly polar missions and can't
>land just anywhere. Also, I don't know DC's crossrange but it is in the
>same ballpark as Shuttle.

I would agree that crossrange is a valid requirement and that since BMDO is
paying the bills, DC should be built the way they want it.  However, crossrange
is not very useful for a commercial launcher, at least as I understand it.
Therefore, the additional penalties in structure and thermal protection that
result from the nose first entry may dissuade commercial designers from
building vehicles this way.  As for crossrange, Gary Hudson wrote in 1991,
"The Delta Clipper ... is now claiming a 1640 nautical miles crossrange, more
than twice that achieved by the winged Space Shuttle."  I attended a seminar
on DC trajectory simulation in which I remember the figure of "about 2000
miles" being tossed mentioned.  This figure would be more recent, but less
precise.  Make of it what you will.

--
Josh Hopkins                                          [e-mail]
     "Physics is like sex: sure, it may give some practical results,
                 but that's not why we do it."
            -R. Feynman

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

Date: Mon, 26 Jul 93 04:23:09 GMT
From: Eric Topp <topp@roses>
Subject: Found your own dark-sky nation?
Newsgroups: sci.astro,sci.geo.geology,sci.space

[e-mail] (Gary Coffman) writes:
: In article <[e-mail]> [e-mail] writes:
: >In article <[e-mail]>, [e-mail] (Gary Coffman) writes:
: >|> So gather your astronomer buddies and buy a Pacific island. If Marlon
: >|> Brando can do it, so can you and a few of your friends. When your nearest
: >|> neighbor is a thousand miles away, it can get real dark.

[snip]

: Uhhh. The original post was meant to be tongue in cheek, now you're
: getting serious. I don't think that most astronomers would really
: want a sea level observatory if they had a choice. The seeing would
: be poor too much of the time.

I thought that seeing had more to do with turbulence than elevation, and
that a large land mass tends to create turbulence.  An island in the
middle of an ocean might not be that bad.  Standing atop a 4300 m volcano
on an island in the middle of an ocean doesn't hurt, either ;^)

: Gary

-=E

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

Date: Mon, 26 Jul 1993 06:42:56 GMT
From: Dave Tholen <[e-mail]>
Subject: Found your own dark-sky nation?
Newsgroups: sci.astro,sci.geo.geology,sci.space

Eric Topp writes:

> I thought that seeing had more to do with turbulence than elevation, and
> that a large land mass tends to create turbulence.  An island in the
> middle of an ocean might not be that bad.  Standing atop a 4300 m volcano
> on an island in the middle of an ocean doesn't hurt, either ;^)

It's just that there aren't any of these.  Mauna Kea is the tallest
available, and it peaks out at 4205 m.

(This message being written at that elevation, by the way.)

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

Date: 26 Jul 1993 06:27:44 GMT
From: Josh Hopkins <[e-mail]>
Subject: GPS in space (was Re: DC-1 & BDB)
Newsgroups: sci.space

[e-mail] (Pat) writes:

>[e-mail] writes:
>>[e-mail] (Pat) writes:

>The whole point of 51 Degree or higher orbit is to avoid single
>vehicle dependency.

>At 28.5 degrees,  only the shuttle could hit SSF with anything
>approaching useful payload and with existing hardware.

There isn't a vehicle on the planet that can hit SSF with existing hardware.
After all, SSF isn't existing hardware.  There has been some discussion of
a smart upper stage for Ariane V designed for Freedom resupply.  This seems
like a fine solution to me.

>Possibly the Ariane 4 could hit 28.5 degrees,  from guyana,  except!!!!
>Ariane 4 is totally booked up for the next two years,

Hmm.  I guess we could call up NASA and politely ask them not to launch
Freedom in the next two years.  I bet we could get them to hold off.

>and ariane
>offers no cost savings on logistics missions  compared to Delta or
>Titan.

Could you give a source for this opinion?  I am under the impression that
Ariane V will be significantly cheaper.

>Materials processing is a primary objective.  In order to do good
>productive work on materials at PMC(permanent Manned capcity)
>one wants a steady flow of materials up and down from the station.
>waiting for quarterly logistics flights from the shuttle  (especially with
>the risk of a shuttle accident and grounding being  high)  is not
>conducive to good station management.  Placing the station in an orbit
>where  other vehicles can support  either materials flow   or
>even logistics (In case of shuttle unavailability)  is
>in my mind good  business sense.

The Japanese designed the HOPE spaceplane for exactly this reason.  They have
since decided that whatever ends up flying will have far to little power to
produce the large amounts of materials they had planned.

--
Josh Hopkins                                          [e-mail]
     "Physics is like sex: sure, it may give some practical results,
                 but that's not why we do it."
            -R. Feynman

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

Date: 22 Jul 93  00:00:00
From: [e-mail]
Subject: Space Movie/PR..
Newsgroups: sci.space

MB>If you want greater public support for the space program, the public
MB>needs to be exposed much much more to it.  Sci.space and
MB>sci.space.shuttle are as close as I can get.

One of the great misconceptions of our time is that people should be
interested in spaceflight as a spectator sport, and that lack of interest
by the public and media is a bad thing.

I would like to propose that it is a good thing when spaceflight is
perceived as being so routine that it is boring and un-newsworthy.





--- WinQwk 2.0b#0

--- Maximus 2.01wb

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

Date: 26 Jul 1993 00:54 CDT
From: [e-mail]
Subject: Test Stands at MSFC (Was Re: Room in the VAB?)
Newsgroups: sci.space

In article <22u370$[e-mail]>, [e-mail] (Pat) writes...
>
>Dennis.
>
>    ASSRM is more then political. it is also environmental.
>that sucker kicks out quite a bit of chlorine gas  as a exhaust product.
>i believe back in the 70's when they were determining wether to
>test the SRBs at Stennis,  it was enough of a concern  that
>they helped tip it from stennis to THiokol.  the desert is pretty
>dry and empty.
>
>    after thiokol got kicked from ASRM,  that option died.
>

Hey pat you shoulda read a little closer. As I posted, we ALREADY are firing
SRB's here at MSFC on the test stands. These are subscale models but they
are still putting out thier stuff. Also remember that this is also the
Redstone Arsenal. We fire all kinds of SRB missles here all the time along
with tank rounds and all kinds of fun fireworks that cause the buildings here
to go shake in the night and day.

Dennis, University of Alabama in Huntsville

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

Date: 26 Jul 1993 06:12:52 GMT
From: Josh Hopkins <[e-mail]>
Subject: Waste Management aboard Skylab and Shuttle
Newsgroups: sci.space

[e-mail] (Kennelmeister) writes:

>Toilet arguements......

>How long have these been raging? 40 years?

Well, toliets in space have been causing problems since before we got into
space.  Heck, we're talking about something that's designed so that the
shit is supposed to hit the fan.

>Here's my 2c. Fell free to tell me that it's totally useless, etc etc

>Fred is big(ish). There's anough room (figuratively speaking) to swing a
>cat inside.

Not a cat you like certainly.  And by the way, cats do not take well to
microgravity--it's been tried.  Althought I suppose if you swing it it would
not be subject to microgravity anymore.  You may be on to something here.

>How about a centrifuge based toilet compartment?

Gravity really isn't worth the extra effort.  I recently read a three page
interview with Rusty Schweickart on exactly this subject.  The Skylab
toilets worked fine. Toilet design is not a trivial issue, but it doesn't
have to be hard.

>We aren't going to be collecting stool and urine samples forever.

I don't think they do anymore, except perhaps for certain specific experiments
on an occasional Spacelab flight.

>Eventually we're just going to be facing problems of waste disposal.

Not really.  The stuff can be tossed overboard.  It has been discribed as
a very impressive sight actually.

--
Josh Hopkins                                          [e-mail]
     "Physics is like sex: sure, it may give some practical results,
                 but that's not why we do it."
            -R. Feynman

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

From: Henry Spencer <[e-mail]>
Newsgroups: sci.space

Subject: Re: DC-X Prophets and associated problems
Message-Id: <[e-mail]>
Date: Mon, 26 Jul 1993 03:32:06 GMT
References: <22peof$[e-mail]> <22pofg$[e-mail]> <[e-mail]>
Organization: U of Toronto Zoology
Lines: 12
Sender: [e-mail]
Source-Info:  Sender is really [e-mail]

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>As I understand it, DC is to be *teleoperated* when flown unmanned. Seems
>to me that would require even more simulator time since it's arguably
>harder to fly remotely than from on board...

DC is always flown from on board, by a computer.  There are no stick-and-
rudder controls for a human pilot, even when one is aboard.  McDD's design
concept is really pushing an idea that gets lip service elsewhere:  the
human as systems manager rather than pilot.
--
Altruism is a fine motive, but if you   | Henry Spencer @ U of Toronto Zoology
want results, greed works much better.  |  [e-mail]  utzoo!henry

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End of Space Digest Volume 16 : Issue 923
------------------------------