Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V09_5/V9_530.TXT

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Subject: SPACE Digest V9 #530

SPACE Digest                                      Volume 9 : Issue 530

Today's Topics:
             space news from May 15 AW&ST
             Re: Space station computers
             Re: new space goals
         Newspaper article on Insat accident results
              Re: Let's go back
----------------------------------------------------------------------

Date: 2 Jul 89 05:44:32 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: space news from May 15 AW&ST

NASA abandons the notion of a serviceable design for the polar platform,
reverting to a one-shot expendable approach.  [Hard to avoid, given the
lack of any way to service it...]

NASA plans to build a ground-based radar system to assess how bad the
small-space-debris problem is, specifically with reference to the space
station.  Existing radars track big pieces but not small ones.

SDI budget cuts slip Zenith Star space-laser experiment two years, at least.

Bush selects "Endeavour" as name of new orbiter, after Captain Cook's first
command, used in exploration of the Pacific, including Alaskan waters.
[As reported by others, AW&ST left out the "u" in the name.]

Authoritative report that the Titan 34D launch on May 10 was a pair of
strategic-forces comsats.  [Said report was later retracted; it was a
snoopsat instead.  The comsat pair is still waiting for launch.]

Magellan doing well en route, with daily star calibration maneuvers being
done to assess gyro drift.

A day before landing, the Atlantis crew replaced one of the orbiter's
five general-purpose computers after it failed.  The orbiter routinely
carries a spare, and the crew are trained in the replacement procedure,
but it took about four hours because the computers are behind some of
the middeck lockers and are not easy to get at.

Atlantis lands successfully at Edwards.  Landing on the lakebed runway
had been planned, but crosswinds were too strong and plans shifted to
one of the concrete runways.  The landing was made there with an 8kt
crosswind, which suited NASA fine, as landing in a mild crosswind has
been a test objective for quite a while.

NASA proposes to switch much of the station's power system from solar
arrays to a solar dynamic scheme.  Solar-dynamic was originally put off
to phase 2, but the technology has developed well and an important
advantage has appeared:  by using a phase-change heat-storage system,
a solar dynamic system can maintain full output even when the station
is in Earth's shadow.  Doing the same for solar arrays requires large
battery banks, which deteriorate and have to be replaced, to the tune
of the equivalent of a dedicated shuttle mission every five years just
for battery replacement.  Solar-dynamic systems also make power growth
cheaper, a significant issue since some feel the station is underpowered.
The station would probably retain one modest solar array for emergency
power.  Station management has not yet approved the switch; general
consensus seems to be that it may be a good idea but it's disturbing
that such major changes are still showing up now.

US and Soviet scientists propose monitoring firing of high-powered lasers
into space by placing scattered-light detectors 1 km or so from suspected
antisatellite-laser locations.  This could help verify a laser-Asat ban.

Soviet shuttle orbiter will appear at the Paris air show, contrary to
earlier reports.  It will be carried there on the new Mriya heavylift
transport aircraft, which will also star at the show.  [This report
quotes Soviet aviation officials as saying that the Paris orbiter will
be a test article, but I think it turned out to be Buran itself.]

Space Services Inc. and Space Data Corp. selected as contractors for
commercial sounding-rocket services being bought by NASA for materials
science.  Contracts are for two launches each, with options on two more.

NASA science managers [now there's a job title for you... :-)] say that
Soviet radarsat reactors will be a "nuisance" to the Gamma Ray Observatory,
requiring careful planning of operations but not badly disrupting them.
Crucial instruments will be turned off for short periods during close
encounters with the radarsats themselves, and will be adjusted to avoid
reporting gamma rays produced by electrons and positrons that the reactors
emit.  This will complicate mission planning but will reduce scientific
returns only slightly.  More reactors in orbit, however, would be bad news.

Martin Marietta gets contract for the space station's Canadian Contribution
Duplication, er excuse me Flight Telerobotic Servicer.  MM's latest design
is much more anthropomorphic than older designs, with a pair of video
cameras with zoom lenses and spotlights in the "head" and a pair of arms
attached to the "shoulders" of a roughly-rectangular equipment box.
There is a third arm, located... um... where a tail would be but in
front :-)... which will anchor the servicer to its work site.  There will
be a flight test in 1991, aimed mostly at human-factors assessment, and
a full flight demonstration in 1993.

SDI prepares to launch a neutral-particle-beam experiment on a sounding
rocket.  The main objective is to examine how the beam propagates away
from the spacecraft and interacts with the near-spacecraft environment.
The hope is to demonstrate that problems with NPB technology, formerly
thought to make it impractical as a useful weapon, have been overcome.

Letter from Michael Lang, commenting on an earlier expendables-are-best
letter:

    "H.L. Anderton is apparently living in a dream world if he thinks
    we would be able to recover from an expendable launch failure in
    a month.  Maybe he forgets that there have been long launch
    delays after every recent failure.  The incidents all have one
    crucial thing in common with the recovery process after the
    Challenger failure -- bureaucrats.  Every time we have a failure,
    it's not the engineers who determine the problems and solutions.
    A bunch of bureaucrats form advisory panels, testify endlessly
    in blue-ribbon, round-table discussions, and make technical
    decisions about systems they may not have seen in years (if ever).
    Meanwhile the technical people, who live and work with these
    systems every day, are forced to worry about layoffs and wait..."
--
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]

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

Date: Thu, 29 Jun 1989 12:17-EDT
From: [e-mail]
Subject: Re: Space station computers

>    At normal viewing distances, 120dpi (which is only twice what
>    my Mac delivers) would be more than acceptable.  32 bit color
>    will probably be standard.  Remember however that the more
>    dpi, the more memory required, the higher the dot clock rate,
>    (faster memory required), and the more bits you have to twiddle
>    to repaint the screen.

120 dpi is not acceptable for archival purposes. 400dpi is probably
marginal. Would you want the Mona Lisa archived for historians at only
120dpi? I wouldn't even store my personal archives at that low a dpi.
And even if you store high and downsample on display, then you still
have to do hardcopy everytime you want to study color pictorial
material.  I would not want to store and display photographic material
at a resolution less than the grain size of the film. This WILL come. I
have talked with library and archive people. BELIEVE ME, 120 dpi isn't
even close to acceptable. Of course, someone has to bust the Adobe Systems
silliness about limiting the output in Postscript to low (400dpi or so)
resolution even on printing, but they won't be able to withstand the
push that I expect in the next decade.

>    Cute, but most people will be keybanging and mousing, because
>     the world runs on shuffling words around.  Unless you are doing
>    3D work, you don't need fancy datagloves.  Voice is fine for

I did not mention datagloves, I was speaking of the Sensor Frame (TM).
And which is faster, pointing with a mouse, clicking to select a tool,
moving to the beginning of a phrase, clicking to select the start of
range, moving to the end, selecting the end of the range, moving to the
target location... Or spanning the text with two fingers, saying
"Move", pointing at the insertion point and saying "HERE"?

>    I'd be surprised to see 64MB PC's this year, especially for

NeXT is only waiting for the quantities to be available. The NeXT
machine as it exists TODAY can handle this. It has simply not been
tested with the new chips.

>    Hey, what's a factor of 2000 between friends?  You may have

Yeah, you are probably right. Probably won't be more than 128GB by
1998...

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

Date: 29 Jun 89 17:19:17 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: new space goals

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Tom Neff) writes:
>>LET'S BUILD A PAIR OF MARS STATIONS, IN ORBIT AND ON THE SURFACE, BY 2040.
>
>You realize, I hope, that that's FIFTY YEARS away, and Apollo only took ten.
>If I was trying to set an ambitious goal, I'd make it initial deployment
>in 2001 and full operation by 2005.  A determined effort ought to be able
>to get the necessary hardware development done in a decade, even starting
>from the current mess.

It took twelve years from Sputnik to Tranquillity.  Twenty years after
*that*, space is once again a certified people-free zone.  Mars is such
a mammoth project (much harder than the Moon) that fifty years seems
reasonable to me.  That's how long people spend building cathedrals
(Robert Schuller excepted).

Which is not to say we couldn't have footprints crunched into Chryse
Planitia in a decade or 15 years if we went all out Apollo-style, making
every compromise possible in mission and infrastructure for the sake of
the symbolic sprint -- Apollo-style.  But what you'd have left would be
another bag of rocks and another failed Roanoak, this time eroding
rapidly in the thin Martian dustwind instead of baking in vacuum silence
on the timeless Lunar grit.

What we can do in 10 years simply doesn't last.  What we can do in 50
might.  I want to follow the Antarctica model - establish an
international scientific outpost in a distant, hostile environment.

By drawing the program out timewise, you provide an ongoing focus of
activity that *defines* a half century of endeavor.  New space powers
like China or Israel can do something useful right away, rather than
concentrating on prestige shots and comsats.  You engage a *generation*
of scientists and spaceflight professionals in significant cooperation,
so that it has a chance of becoming second nature.

>Let's see...  The USSR does the heavylift boosters and nuclear-electric
>space propulsion, since they already have most of that done or in the
>works.  Japan does the electronics, of course.  ESA builds the crew
>quarters, based on Spacelab experience.  The US does... um... well...

Simple, Henry.  The US builds an elaborate Peace Shield to protect the
Mars outpost from surprise nuclear attack.  :-)

Oh yes, and you "North Americans" can build some more RMUs.  It's what
you do, after all -- and you do it so well.  Who'd have guessed that
Canada's role in space would turn out to be exporting arms?

>NASA is to spaceflight as the  |     Henry Spencer at U of Toronto Zoology
>US government is to freedom.   | uunet!attcan!utzoo!henry [e-mail]

Let's see... Glavkosmos is to spaceflight as the USSR is to vodka?  :-)

--
"My God, Thiokol, when do you     \\    Tom Neff
want me to launch -- next April?"  \\    uunet!bfmny0!tneff

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

Date:     Thu, 29 Jun 89 15:02:19 CDT
From: Will Martin <[e-mail]>
Subject:  Newspaper article on Insat accident results

This was in the St. Louis Post-Dispatch, Wednesday, June 24 1989, page 3C:

SATELLITE LAUNCH WEEKS AWAY

Washington -- A "very unfortunate" launch pad accident last week in
Florida will delay what was to have been the first major private-sector
US launch of a satellite by at least several weeks and possibly many
months, officials say.

McDonnell Douglas Corp. was scheduled to loft a communications satellite
for the government of India aboard its Delta 2 rocket on Thursday,
making it the first American company to dispatch a paying customer's
cargo to orbit.

The company is one of three major American rocket makers trying to
compete for commercial satellite business with the European consortium
Arianespace, which has cornered more than half the free world market.

The competition is an outgrowth of the Reagan administration's efforts
to encourage development of a private-sector launch industry. Previous
US launches have been conducted by NASA or the Air Force.

The accident happened June 19, when a hoist cable snapped, allowing a
heavy steel hook to fall on the $70 million Insat 1D satellite and
damage a critical antenna.

The cable was part of a 5-ton bridge crane that had been used to lift
the satellite 116 feet to the top of a Delta 2 rocket, built by McDonnell
Douglas Space Systems Co. of Huntington Beach, CA, at a launch pad
leased from the Air Force at Cape Canaveral.

The satellite has been removed from the rocket and sent to the company's
Florida facility, where potentially lethal propellants must be unloaded
before the satellite's manufacturer, Ford Aerospace Communications Co.
of Palo Alto, CA, and a representative of the customer, India's
Department of Space, will be able to assess the damage, according to
McDonnell Douglas spokesman [sic] Sheila Carter.

The company plans to proceed with other launches scheduled on its Delta
rockets, she said, including a Navstar navigation satellite in late July
and a British media satellite in mid-August.

"There's a good chance the satellite will have to be sent back" to the
plant in California, said Susan Pearce of Ford Aerospace. There is no
spare antenna, and a new one may have to be built.

Some sources said that finding a new launch slot might take longer than
repairing the satellite -- up to a year if the launch schedule isn't
juggled to make a new opening.

In addition to the Delta boosters, Martin Marietta Astronautics Group of
Denver is marketing a commercial version of the big Titan 34D rocket,
and General Dynamics Corp. of St. Louis is selling Atlas-Centaur rockets.
***End of Article***

Hope this is of interest and doesn't duplicate something already posted!
(I see the Space stuff on the Digest and it runs about a week or so
later than the USENET.)

Regards, Will Martin

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

Date: 28 Jun 89 23:22:47 GMT
From: amdcad!weitek!sci![e-mail]  (Dave Rickel)
Subject: Re: Let's go back

In article <[e-mail]>, [e-mail] (Paul Dietz) points out that i goofed.

Damn.  Don't hire me as an astrogator.  I should have realized that the numbers
looked funny.

Anyway, new numbers.  Some of them are more accurate than the last bout.  I've
probably made some more stupid mistakes, but what the hell.


LEO (500 im) to lunar transfer orbit (LTO) (figure earth escape orbit):
    3.153 km/sec

LTO to LLO (200 km)
    0.698 km/sec (this number is probably high, but i didn't want to
            work out three-body problems)

LLO to Lunar surface
    1.766 km/sec

LTO to Lunar surface (this number is also probably high, for the same reasons)
    2.411 km/sec

1 minute hover at lunar surface
    0.097 km/sec

3 minutes hover
    0.292 km/sec


OK.  From LEO to lunar surface is 3.153 + 2.411 + .292 is 5.9 km/sec.  Call it
6.  That's still high enough that you'd probably want to use Hydrogen/Oxygen,
but it's considerably better than before.  If you launched a single-staged
vehicle from LEO to the moon, and its rockets were as efficient as the space
shuttle's (Isp = 4.464 km/sec in vacuum), it'd end up at about 74% fuel, the
rest structural and payload.  You can do better by having disposable fuel
tanks.  Let's see.  Assume 10% of the weight of a fuel tank is plumbing and
tank (a bit high, i think).  I think that works out to 50 tons fuel + 5 tons
tanks for the burn from LEO to lunar transfer, 20 tons fuel + 2 tons tanks
for lunar transfer to lunar orbit, 20 tons for the lunar lander (engines,
crew compartment, landing gear, structure, etc.)  So about 100 tons into
orbit to land 20 tons on the moon.  At $8 million/ton, that's $800 million
per lander, not counting materials and development.

For the trip back, assume 10 tons for the reentry capsule, 3 tons engines, 2
tons misc, we need about 2.7 km/sec to launch from lunar surface to earth's
atmosphere.  14 tons fuel + 1.4 tons tanks + 15 tons payload = 30.4 tons.

Typical launch configuration might be:  launch and land fuel tanker.  Launch
and land cargo rocket.  Launch and land astronauts (selenonauts?).  Astronauts
spend first day transfering fuel from fuel tanker to their launch vehicle,
subsequent days exploring, setting up lunar base, etc.  Astronauts can be
periodically resupplied from earth, each resupply ship containing enough
fuel to top up the tanks in the return rocket.  So, maybe five ships all in
all, for, umm, $4 billion in launch costs.  An order of magnitude cut in
launch costs would help a great deal.


david rickel
decwrl!sci!daver

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

End of SPACE Digest V9 #530
*******************