Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v11_1/v11_128.txt

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Subject: SPACE Digest V11 #128

SPACE Digest                                     Volume 11 : Issue 128

Today's Topics:
             Re: SR-71:  LA to DC
       Re: Americanisms (was: Ulysses Update - 03/06/90 {sic})
              Re: hubble telescope power
       Re: Americanisms (was: Ulysses Update - 03/06/90 {sic})
       Re: Americanisms (was: Ulysses Update - 03/06/90 {sic})
               Re: NASA SR-71's
         Re: space news from Jan 29 AW&ST etc
      Re: Fun Space Fact #1: Launcher Development Costs
                Command errors
            Re: Galileo Update - 03/05/90
              Re: hubble telescope power
----------------------------------------------------------------------

Date: 8 Mar 90 01:17:36 GMT
From: ogicse!zephyr.ens.tek.com!tektronix!sequent![e-mail]  (Cliff White)
Subject: Re: SR-71:  LA to DC

In article <[e-mail]> [e-mail] (Bob Sutterfield) writes:
%In article <[e-mail]> [e-mail] (John H. Kim) writes:
%   ...SR-71... LA to DC in 01:08:15... target time was 01:04:00...
%
are there distance and velocity numbers to go along with the time?
i'd like to know just how fast it was going...


--
cliffw

'If we can't fix it- we'll fix it so nobody can'- B. Gibbons

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

Date: 8 Mar 90 20:51:59 GMT
From: elroy.jpl.nasa.gov!aristotle![e-mail]  (Peter Scott)
Subject: Re: Americanisms (was: Ulysses Update - 03/06/90 {sic})

In article <[e-mail]>, [e-mail] (John Shipman) writes:
>
> Bravo!  The YYYY-MM-DD ordering is also an ANSI (American National
> Standards Institute) standard for date recording in data processing.
>
> I feel that it is the only logical format for several reasons:
>[...]

Aw, why not go the whole hog and use decimal Julian days?  As exact
as you please, unambiguous, and only one field.  :-)

If you date your checks or your letters in ISO format then it might
be useful to you, otherwise let's feed machine format data to machines
and save people format data for people.  Let's find an unambiguous format
for people.

This is news.  This is your       |    Peter Scott, NASA/JPL/Caltech
brain on news.  Any questions?    |    ([e-mail])

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

Date: 8 Mar 90 16:46:49 GMT
From: wuarchive!cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: hubble telescope power

In article <[e-mail]> [e-mail] (Roy Smith) writes:
>... Is it concievable
>that large telescopes might be built on the moon in the next 10-20 years?

Conceivable, yes.  It could have been done 10-15 years ago.  Whether it
*will* be done is another question.  Bush has been making the right sorts
of noises, but so far he hasn't been backing them up much.
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: 8 Mar 90 19:33:39 GMT
From: [e-mail]  (Harold G. Corwin Jr.)
Subject: Re: Americanisms (was: Ulysses Update - 03/06/90 {sic})

In article <[e-mail]>, [e-mail] (C.E. Thompson) writes:
> It can be quite confusing for us to read dates in your weird local format :-)
> I am not suggesting you should use *our* weird local format, though. How
> about using ISO format dates? (e.g. 1990-03-06, though the ISO standard
> does allow some other seperators than '-' to be used, I think)

I agree.  I spent 5 years in Scotland, and as a Yank, had continual problems
with this.  I still do to the extent that I must stop and think every time I
see a numerical date.  For my own use, I get around the problem by using dates
with the format dd Month yyyy (e.g. 8 March 1990).  But I certainly wouldn't
mind seeing the ISO format adopted here (and in my astronomy, I do).  To some
extent, it already is, of course:  all the digital watches and clock/calculators
that I've seen use ISO dates so that they can be sold world-wide without
annoying (too much, anyhow) the paying customers.

Still, I expect the US to adopt ISO format dates about the same time that
Congress passes legislation to adopt the metric system.  The Berlin wall came
down in my lifetime, but I certainly don't expect to live to see another
miracle!
Harold Corwin
--
Harold G. Corwin, Jr.
  UUCP: {backbonesite}!{noao,cs.utexas.edu}!utastro!hgcjr
  Internet: [e-mail]           MaBell: 512-471-7463
  Astronomy Dept., RLM 15.308, Univ. of Texas, Austin, TX 78712-1083

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

Date: 8 Mar 90 16:43:22 GMT
From: wuarchive!cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Americanisms (was: Ulysses Update - 03/06/90 {sic})

In article <[e-mail]> [e-mail] (C.E. Thompson) writes:
>>             10/05/90 - Launch from Space Shuttle
>> ...
>It can be quite confusing for us to read dates in your weird local format :-)
>I am not suggesting you should use *our* weird local format, though. How
>about using ISO format dates? (e.g. 1990-03-06...

Better yet, how about using names for the months, e.g. 5 Oct 1990, which
is completely unambiguous and easier for humans (as opposed to computers)
to read.
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: 8 Mar 90 19:48:29 GMT
From: skipper![e-mail]  (Mary Shafer (OFV))
Subject: Re: NASA SR-71's

In article <[e-mail]> [e-mail] writes:

>It is my understanding NASA will be receiving three SR-71's for high
>altitude research.  With the proper sensors installed and aided by inflight
>refueling, could one of these make a nonstop flight around the world, passing
>over the North and South Poles to study the holes in the ozone layer?  This
>would be an aviation first.  It would also tie in with NASA's Mission to Planet
> Earth.

Not "high altitude research" in the sense of research into the higher
altitudes, but rather in high-altitude _flight_ research.  The
aircraft are at the Ames-Dryden Flight Research Facility, which is
involved in research in the behavior/dynamics/etc of aircraft.
Atmospheric research is based at Ames-Moffet, using slower aircraft.
They're doing a good job, so why use something as expensive as the
SR-71, just for "an aviation first"?

I wouldn't rule out atmospheric sampling, but running a hot Mach-3
airplane through your sample space may distort the results you're
looking for.

We're probably going to be hesitant to modify the airplanes enough
to do this, too.

> As another possible use for these Blackbirds, why not launch Pegasus from
>them at 80,000 feet plus instead of from a B-52 at only 40,000 feet?

Because Orbital Science Corp. can't afford to pay for the required
analysis, wind-tunnel testing, aircraft modification, envelope
expansion, and operational costs.  We're talking about _really_
expensive here.  You don't just hang Pegasus on the SR-71 (to begin
with, there's nowhere to hang it), take off, and launch.

The B-52 is available, already configured and tested, and cheap.  OSC
is using it because they can't afford to modify and clear any
aircraft, even a third-hand one, so there's no way they'd be able to
afford the SR-71.  We won't do it; it's not our problem.  Besides, we
can't afford it either.

Look, all you purists don't want NASA involved in space anyway.  You
can't suddenly decide to include us, just because we just got a nifty
airplane that you think would be neat to use.  :-)  (Jealousy, pure
jealousy.)

--

Mary Shafer  [e-mail] or ames!skipper.dfrf.nasa.gov!shafer
         NASA Ames Dryden Flight Research Facility, Edwards, CA
                   Of course I don't speak for NASA

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

Date: 7 Mar 90 18:03:32 GMT
From: usc!cs.utexas.edu!mailrus!jarvis.csri.toronto.edu!helios.physics.utoronto.ca!ists!yunexus!utzoo![e-mail]  (Henry Spencer)
Subject: Re: space news from Jan 29 AW&ST etc

In article <[e-mail]> [e-mail] (Todd Johnson) writes:
>>Truly recommends to Space Council that "the first decade of the 21st
>>century" be the target goal for a lunar base.  [Call it 19 years.
>>Apollo took 8.  I'm not impressed.]
>
>We have paid for that 8 year leap every day since then. The quick 8 years
>was a "go there and do it" plan, it did not have the staying power
>required for a permanent manned presence (or a permanent observing
>presence, let alone manned)...

Can you justify this, with references?  If you go digging for them, you'll
find no shortage of detailed planning for long-stay missions leading into
permanent bases.  The 8 years was a "go there, do it, and build from there"
plan; it very definitely had staying power, which it was not permitted to
exercise.  Apollo would have been very different, and quite a bit cheaper,
if it had been planned to fly 7 landings and no more.  (For one thing, KSC
would not have been built to support 30+ launches a year!)  The politicians
may never have intended to fund a long-term lunar program, but the technical
people very definitely planned for one.  Please read something about the
follow-on plans before you claim there weren't any.

It is true that Apollo's 1969 deadline caused some compromises on the
"not good, but Wednesday" principle, but although the resulting hardware
wasn't ideal for bigger things, it was eminently usable for them.  Read
about the Long-Stay Lunar Module, or the LM Truck, or the various
plans for larger cargo derivatives of the LM as the logistics support
for longer -- eventually permanent -- missions.  It's enough to make
you cry.

>I suspect that the 19 years includes
>building up an infrastructure and producing maintainability.

The same infrastructure and maintainability we had at the end of those
8 years, and then threw away, you mean.
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: 8 Mar 90 17:23:33 GMT
From: elroy.jpl.nasa.gov!usc!brutus.cs.uiuc.edu!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Fun Space Fact #1: Launcher Development Costs

In article <[e-mail]> [e-mail] writes:
>>> But I don't think the 747's safety margins are much smaller than
>>> those of a Cessna; if anything, it has to meet rather tougher
>>> standards.
>
>And is the 747 also no more complex than the Cesna?  Complexity is
>swapped off with the stress the parts have to take.  That's what
>that redesign you say is necessary *does*.

Upgrade the Cessna to match the 747 specs (scaled down in size but keeping
the stringency), and you will find it gets a lot more complex too.  Much
of that complexity is things like fussier standards and greater demands
in fairly size-independent ways.  There are things like hydraulic boost
for controls that the Cessna doesn't need, but we *are* talking about two
orders of magnitude of size difference in this example.
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: Thu, 8 Mar 90 21:32:19 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Command errors


>Date: 5 Mar 90 18:18:11 GMT
>From: cs.utexas.edu!ut-emx![e-mail]  (Anita Cochran)
>Subject: Re: Magellan Update - 03/02/90 -- now reprogramming spacecraft

>Yes, these things are documented and remembered.  As anyone who has ever
>worked with NASA can attest, NASA doesn't do ANYTHING without copious
>amounts of documentation.  A mission generates file cabinets worth of
>documentation.  And we don't uplink anything to a spacecraft until it
>is fully tested out on the ground-system and documented.  This results
>in very safe operations and the ability to fix things but means we
>cannot operate in anything like real time.

>As an example, I am involved with the Comet Rendezvous/Asteroid Flyby (CRAF)
>mission.  If we decided one day that we want to point to a particular
>feature on the comet and cycle through 5 filters, it will be a minimum
>of 4 weeks from the time we request it until the time it is uplinked
>and executed.  Obviously, this takes away sponteneity!  First and
>foremost is spacecraft safety.  We scientists are trying to shorten
>the time but we are not winning the battle.

> Anita Cochran  uucp:  {noao, ut-sally, ut-emx}!utastro!anita
>                arpa:  [e-mail]
>                snail: Astronomy Dept., The Univ. of Texas, Austin, TX, 78712
>                at&t:  [phone]

I've been meaning to post a question on this topic. We all know how important
it is to send only correct commands to robot space probes. The US lost contact
with a Viking lander, and the USSR with Phobos 1, because of incorrect
instructions sent from mission controllers. I've read about the elaborate
simulation and approval process required for transmissions to the Voyager
spacecraft, the handshaking protocol to insure correct reception, and the
complex backup programs (previously loaded) to continue the mission in case
the spacecraft receivers should fail. One would think that the problem is well
in hand. HOWEVER:

I believe both Galileo and Magellan have already gotten in trouble at least
once because of incorrect instructions. On a recent Space Shuttle mission,
an incorrect transmission from mission control caused the shuttle to start
tumbling. One gets the impression that controllers have become more careless.
The mission updates we receive on the net are also somewhat disconcerting,
at least to a layman:

>             Galileo Mission Status Report
>                January 12, 1990

>     Two SITURNS to the Sun were successfully performed without incident
>on January 9 and January 12. A total of 1151 real-time commands have been
>transmitted to Galileo.  Of these, 845 have been pre-planned in the
>sequence design and 306 were not.  In the past week a total of  61 real-time
>commands were transmitted; 1 was pre-planned and 60 were not.  To date a
>total of 120 contingency commands have been generated and 4 contingency
>commands have been transmitted; none were transmitted this week.  This weeks
>totals contain 10 commands from EV-05.

This *seems* to say "845 commands were carefully reviewed and simulated before
being sent to Galileo. 306 commands were just typed in on the spur of the
moment because they seemed like a good idea at the time." How carefully are
these unplanned commands controlled? Do they represent alternate sequences
that were pre-planned though their use was not expected?

To be fair, the craft seem to be designed with considerable "idiot-proofing",
so that recovery is possible from a high percentage of the possible wrong
commands. Hopefully, both craft have control algorithms that would permit
them to recover orientation if they were to tumble. Does either have a
complete mission algorithm to use in the event of total receiver failure?

It is also true that rapid response is desirable in many cases. I suspect that
Voyager's coverage of Triton was less than optimum, because when the photo
schedule was being established, it was thought that the moon was larger than
it turned out to be, so many of the pictures included a lot of empty space.
A quick response was also necessary when Galileo's camera shutter went
berserk at Venus, so the problem could be corrected before the shutter wore
itself out. (Does anybody know the details of the recovery process? I have a
mental image of everybody suddenly gasping in horror (like Doc Brown in "Back
to the Future" when his model car set fire to the lab), then rushing around for
a while before the decision was made to turn off the shutter controller.)

Does anyone have a control system model for Galileo? Something comparable
to a user's guide to a microprocessor would be ideal, but a description
in less detail would also be greatly appreciated. From the descriptions
on the net, I get the impression that Galileo has on the order of 50-100
major components that can be turned on and off, plus a good number of
processors and programmable controllers.
                       John Roberts
                       [e-mail]

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

Date: 8 Mar 90 16:38:19 GMT
From: pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo!dciem!nttor!contact![e-mail]  (Brave Sir Robin)
Subject: Re: Galileo Update - 03/05/90


How protected is the Galileo Probe agaisnst Solar Flares from the sun?
Will it come close enough to the sun to worry about theis?
--
 Jamie Woods                ._o
 srobin@contact               |>
                              4
 "Into every day, a little Cha*s must call."

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

Date: 7 Mar 90 15:53:21 GMT
From: usc!zaphod.mps.ohio-state.edu!rpi!sci.ccny.cuny.edu!phri![e-mail]  (Roy Smith)
Subject: Re: hubble telescope power

[This no longer has anything to do with the shuttle, so I've dropped
sci.space.shuttle from the Newsgroups line]

    There was an article in a recent SciAm about observatories on the
far side of the moon.  It seems like an ideal place; no atmosphere, low
gravity, near-perfect radio frequency shielding from the Earth, the
possibility of *very* long baseline interferometry, etc.  Is it concievable
that large telescopes might be built on the moon in the next 10-20 years?
--
Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
[e-mail] -OR- {att,philabs,cmcl2,rutgers,hombre}!phri!roy
"My karma ran over my dogma"

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

End of SPACE Digest V11 #128
*******************