Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO541.TXT

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Date: Sun, 13 Dec 92 05:07:15
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #541
To: Space Digest Readers
Precedence: bulk


Space Digest                Sun, 13 Dec 92       Volume 15 : Issue 541

Today's Topics:
                                Aurora
              Cassini Undergoes Intensive Design Review
                         Hypergolic Hybrids?
                             liquid fuels
            Re: Cassini Undergoes Intensive Design Review
                       Saturn history (2 msgs)
                       Scud Missile technology
                            Space docking
                         Space suit research?
                            Space Tourism
                      SSF Deputy Dir. Interview
           Terminal Velocity of DCX? (was Re: Shuttle ...)
                               Titan IV
               what the little bird told Henry (2 msgs)

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Date: 12 Dec 92 20:12:00 GMT
From: [e-mail]
Subject: Aurora
Newsgroups: sci.space

Some other reports on Aurora from southern California:

On many Thursday mornings, this area is being shaken by earthquake-like
tremors which are supposedly sonic booms from some secret plane.

The Los Angeles Times reported during the late 1980's that airline pilots
were seeing delta winged aircraft flying extremely high and fast over the
Pacific Ocean. At the time, the LA Times speculated that the mystery
aircraft was a prototype A-12, a project subsequently cancelled by the
DoD, due to massive cost overruns....

___ WinQwk 2.0b#0

--- Maximus 2.00

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

Date: 11 Dec 92 18:28:29 GMT
From: Frank Crary <[e-mail]>
Subject: Cassini Undergoes Intensive Design Review
Newsgroups: sci.space

Sender: USENET News System <[e-mail]>
Organization: University of Colorado, Boulder
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In article <[e-mail]> [e-mail] (Hayim Hendeles) writes:
>>     After flybys of Venus (twice), Earth and Jupiter as it loops
>>around the sun to pick up energy, Cassini will arrive at Saturn
>>in November 2004, beginning a four-year orbital tour of the
>>ringed planet and its 18 moons. The Huygens probe will descend to
>>the surface of Titan in June 2005.

>Pardon my asking an ignorant question, but I can't understand why it
>should take 7 years to get to Saturn. When Voyager went to Jupiter and
>Saturn, it took (if I recall correctly) 4 years and a Jupiter flyby to
>make it to Saturn. Here, you are using 4 flybys, and it's taking you 7
>years!

After the Challenger failure, NASA added a safety requirement that
nothing launched in by a space shuttle may use liquid fuels. That
means Cassini must use lower-energy solid rockets instead. As a
result, a direct launch to Saturn (or a single Jupiter fly-by on
the way) is not possible. A long VEEJGA series of fly-bys of the
inner planets is required to gain suffiecient energy.

>I would think that if you were to adjust the launch date so that
>Jupiter and Saturn were in the same relative positions as they were in
>1977 (when Voyager was launched), you could do the same trick again (in
>the same 4 years).

While the Earth/Jupiter/Saturn geometry is different, I don't think it
it sufficiently worse (in terms of time and energy) than that of the
Voyager fly-by. In any case, waiting for the optimum geometry isn't
really possible: It would take many decades...

                                              Frank Crary
                                              CU Boulder

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

Date: Sat, 12 Dec 1992 20:08:55 -0500
From: Lawrence Curcio <[e-mail]>
Subject: Hypergolic Hybrids?
Newsgroups: sci.space

I was wondering if anyone ever played with the idea of hypergolic hybrid
rockets. It seems to me this would solve a lot of problems. I even have
a family of propellant combinations in mind.

Diphenyl amine, when reacted slowly with warm, dilute nitric acid yields
a tarry sludge that breaks up into delightful free radicals when heated.
This sludge can be mixed with monomers (e.g.; styren) to form materials
with more desireable physical properties. In fact, the sludge takes the
place of a curing agent (free radical initiator). Said materials would
likely be hypergolic with N2O4 or RFNA.

The system could then be programmed with paper tape...

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

Date: 13 Dec 92 01:39:07 GMT
From: Henry Spencer <[e-mail]>
Subject: liquid fuels
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Dave Michelson) writes:
>>-After the Challenger failure, NASA added a safety requirement that
>>-nothing launched in by a space shuttle may use liquid fuels...
>>I think you mean *cryogenic* fuels. Magellan, Galileo, and Ulysses all
>>use liquid fuels.
>
>The major problem with cryogenic fuels is that they boil off and the
>gas must be vented.  This becomes a real problem if the upper stage
>is located inside the shuttle cargo bay.  The modifications that must
>be made to the shuttle are non-trivial.

Sorry, wrong.  Cryogenic fuels fly in the payload bay on every extended-
duration shuttle flight.  The shuttle's fuel cells use liquid hydrogen
and liquid oxygen, and the extended-duration pallet for the cargo bay
(first flown recently) is basically a set of LH2 and LOX tanks.

Shuttle/Centaur, the launch system originally meant for Galileo (as well
as the other two, but it was the massively-overweight Galileo mission
that drove its specs), died partly because of an acute attack of timidity
after Challenger, partly because people distrusted some aspects of Centaur's
construction, and partly because Centaur+Galileo was so heavy that it led
to problems like needing to jettison its fuel before an emergency landing.
A somewhat smaller LOX/LH2 stage with more conservative construction could
probably be certified for shuttle use even now, but nobody wants to try.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 13 Dec 92 01:42:27 GMT
From: Henry Spencer <[e-mail]>
Subject: Re: Cassini Undergoes Intensive Design Review
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Ross Cunniff) writes:
>You have to consider that Cassini (and Galileo) are *HUGE* interplanetary
>probes.  Voyager was a lightweight - a Titan II launch sent it on a direct
>orbit to Jupiter, and then it used a gravity assist to Saturn and beyond.

Small correction:  Voyager flew on a Titan III-Centaur, the heaviest booster
the US had at the time (having abandoned the Saturn V and not yet flown the
shuttle).
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 12 Dec 92 02:42:14 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Saturn history
Newsgroups: sci.space

>In article <[e-mail]> [e-mail] (Pat) writes:
>>>The first Saturn I flew on 27 Oct 1961, actually.
>>
>>So if the Saturn I  was ready in 61,  why didn't they use it for
>>Gemini?
>
>The test flights needed to make it ready (by von Braun's standards) covered
>the next several years.  For one thing, the first few flights had no upper
>stage and were incapable of making orbit.
>--
>"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
>       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry
>
    Besides, wasn't the driving force in the Gemini delays of 1964 the
    spacecraft, not the booster? Titan II was more or less ready.

    -Brian


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

Date: 12 Dec 92 04:32:16 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Saturn history
Newsgroups: sci.space

>This is very true and also what Von Braun wanted to do with the Saturn V. They
>wanted to fly the Saturn first stage, the two stages, etc.... The success of
>the Saturn IB flying the SIVB Saturn stage allowed them to do what they
>called "full up" testing, where the launched the full stack on  the first
>SV flight.
>
>By the way the Saturn I had a perfect record, 28 launches and no failures.
>Also a thing of note is that the Centaur was originally designed and flown
>on the Saturn I as the upper stage.
>
>Dennis, University of Alabama in Huntsville.
>
     Centaur on the Saturn? I think I remember that it was considered
     as a fourth stage for Saturn 5 (with early Voyager planning?) but
     I believe you're confusing the RL-10 and the Centaur. RL-10
     powered the S-IV (predecessor to the J-2 powered S-IVB) but I
     don't think Centaur ever flew anything other than Atlas or Titan.

     -Brian


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

Date: 10 Dec 92 00:01:42 GMT
From: Frank Dahncke <[e-mail]>
Subject: Scud Missile technology
Newsgroups: sci.space

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

>I have yet to uncover exactly what a Scud missile is.
>I know what it does. I know that its NATO derivation (SS-1A) is similar to the
>earliest Soviet missile, the SS-1 - a V-2 derivative - but the Scud is in no
>way a dervivative of the SS-1.
>Is the Scud a liquid fuel missile? Is it a solid? If liquid, what fuels does
>it use? What is its engine designation? What design bureau created its engine?
>What is its specific impulse?

All those and similar questions can and will be answered on
sci.military.

                  Hope this helps,

                          Techno
--
| [e-mail] ||| Please do not e-mail from outside Germany ! |
| [e-mail]   / | \  Hardcore ST user ! ====================== |
| Nothing that's real is ever for free, you just have to pay for it sometime. |
|                                       (Al Stewart)                          |

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

Date: 11 Dec 92 18:57:02 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: Space docking
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

>[e-mail] (Gary Coffman) writes:

>>That's an interesting question anyway. How is docking with Freedom
>>supposed to be handled?

>Unless it's changed since I saw it described, basically the shuttle gets
>close, and then the station's arm reaches out, grabs it, and moves it
>into position.  For some of the early assembly, it'll be vice-versa with
>the shuttle arm doing the work, but the shuttle arm isn't strong enough
>to move the whole shuttle around routinely.

>This makes considerable sense, in general.  For routine use, you want a
>docking method that tolerates considerable error.  Getting within the
>"capture volume" of an arm is a lot less fussy than making the docking
>yourself.

This is also consistant with what I've read about rendezvous procedure.  Since
SSF is both expensive and fragile ground control is planning to be very
careful about slinging big vehicles around it.  Rather than aiming for the
docking port, you aim for a spot next to it, and set up your trajectory so that
if the vehicle looses power at any point it will just glide on by.  Once you
get close, the arm guides you in.

It's possible this could change if we decide to use the Russian APAS system.
From what I've heard it's very rugged and well thought out.
--
Josh Hopkins                                          [e-mail]
                        Ho^3     !=L

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

Date: Sat, 12 Dec 92 21:30:55 EST
From: John Roberts <[e-mail]>
Subject: Space suit research?

-From: [e-mail] (Frank Crary)
-Subject: Re: Space suit research?
-Date: 25 Nov 92 04:45:43 GMT
-Organization: University of Colorado, Boulder

-In article <[e-mail]> [e-mail] (Bruce Dunn) writes:
-[JR]:
->> Apparently anything significantly below 3 psi partial pressure of oxygen
->> is a potential health risk, unless you have many generations of ancestors
->> who lived in the mountains.

-I'm not sure what you mean by "significantly", but this certainly doesn't
-apply to ~2 to 2.5 psi oxygen: The residents of Aspen, many (most?) of
-whom have zero generations of ancestors who lived in mountains, live
-and work at such oxygen pressures, with no visible problems. Further,
-people with no hereditary _or_ personal adjustment to low pressures
-routinely go they to ski (which, if anything, requires slightly above
-normal consumption of oxygen.)

I finally found the article. It's in the October, 1992 issue of Scientific
American, pp. 58-66, and is "Mountain Sickness", by Charles S. Houston, a
mountain-climbing physician who specializes in high-altitude research. I'll
try to post a summary of the article:

The only problems dealt with in the article are those associated with
hypoxia - breathing air at low pressure, or breathing oxygen-depleted air
at sea level pressure. Prolonged hypoxia leads to a set of physiological
changes called acclimatization. These physiological changes can lead to
serious health problems. (Note that full partial pressure of oxygen but
lower total pressure is a separate issue.)

Mountain sickness encompasses a wide range of symptoms, which vary widely
from individual to individual. Among the observed phenomena:
 - The reduced supply of oxygen leads to "overbreathing", which in turn
   seriously depletes levels of carbon dioxide, causing the pH of the
   body fluids to change. The kidneys are then forced to excrete biocarbonate
   to try to restore the balance. The rate of breathing is controlled by
   centers in the midbrain that are responsive to CO2 levels and blood pH,
   and also by the carotid bodies (small collections of cells in the neck),
   which are responsive to oxygen levels. The condition of hypoxia often
   causes dominance to shift between these two control mechanisms, resulting
   in periodic, or Cheyne-Stokes breathing, in which a period of rapid deep
   breathing is followed by a shallow breathing, and a complete cessation of
   breathing for a period of eight to ten seconds before the cycle repeats.
   This effect is more pronounced during sleep, and results in a net reduction
   in oxygenation of the blood. It is common above 9000 feet, and universal
   at higher altitudes.
 - Hypoxia tends to lead to increased blood flow to the brain, which causes
   an accumulation of fluid in the brain. This in turn causes general and
   localized increases in pressure, which results in headaches, staggering,
   difficulty in performing fine-motor skills, mental confusion, hallucinations,
   and sometimes death. These effects can occur at altitudes as low as 9000
   feet. Countering cerebral edema is hypocapnia (decreased carbon dioxide),
   which can lead to decreased blood flow to the brain (and oxygen deprivation).
   Whether the net blood flow to the brain is increased or decreased depends
   on the individual.
 - There are many hormonal changes. An increase in the hormone erethropoetin
   stimulates the production of red blood cells. This in turn, can actually
   impede oxygen flow to tissue, increases the viscosity of the blood, and
   can cause extensive clotting, and sometimes congestive heart failure (the
   volume output of the heart is greatly increased during acclimatization).
 - Normally, between 20 and 30 percent of the body's capillaries are inactive.
   With acclimatization, the number of capillaries in active use can be
   increased. Enzyme changes in the cells can enhance anaerobic metabolism.
 - Above 10000 feet, the supply of supply of oxygen to the eyes is decreased
   to the extent that vision in dim light is decreased by 50%. Above
   14000-15000 feet, the veins and arteries in the retina can double in size,
   often causing small hemorrhages. These are usually unnoticed, and it is
   not known whether they represent a health hazard. There is some concern that
   bleeding takes place elsewhere in the body, for instance in the brain,
   which can lead to permanent damage after repeated or prolonged exposure.
 - Hypoxia tends to increase the contractility of the small arteries in the
   lungs, increasing pressure. This in turn stimulates the production of
   biologically active substances, which can have a whole range of side
   effects, and also causes the leakage of plasma and red blood cells.
   Most people going to even such moderate elevations as 8000 feet experience
   some buildup of fluid in the lungs. This fluid can enter the alveoli, and
   sometimes causes drowning.
 - The "sodium pump" mechanism of the cells, which normally uses as much as
   20% of the body's intake of oxygen, can undergo partial failure under
   hypoxia. This causes the cells to build up excess sodium and leak excess
   potassium, upsetting the water balance, and leading to edema.

In many cases, acclimatization can partially offset the symptoms of mountain
sickness. But even so, every 1000 foot increase in elevation reduces maximum
work capacity by 3 percent. Populations that have lived for many generations
at high altitudes show adaptations such as larger lungs, greater amounts
of hemoglobin, and more or larger or differently placed mitochondria. But
no humans have adapted permanently to elevations above 17000 feet - sea-level
dwellers who move to 17000 feet can stay there for only a few months before
deterioration outstrips acclimatization.

The author recommends that climbers ascend no more that 2000 feet a day
above 7000 feet. There are several drugs that can be used to relieve
some of the symptoms of mountain sickness - taking more salt than usual
is *not* recommended. It is emphasized that if serious symptoms develop,
the most important thing is to get to a lower elevation (especially at night).

It appears to me that while mountain sickness affects some people much more
than others, a low partial O2 pressure causes some harmful effects to just about
everybody. In light of the many physiological changes that take place, I think
that it would be unsafe to introduce a low-oxygen atmosphere to manned
spacecraft without considerable further investigation.

John Roberts
[e-mail]

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

Date: 11 Dec 92 18:43:47 -0600
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Space Tourism
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Josh 'K' Hopkins) writes:
> So, if 350 people will pay
> $52,000 for a vehicle that isn't flying and isn't all that heavily advertised
> I think we can assume that this price will provide a big enough market for
> space tourism.  The next question is how much higher it can get before the
> market dries up.  Is there any other data out there?  What's the maximum that
> real people pay for really cool Earth-bound trips?  Anyone ever priced a trip
> to Antarctica?

Ah, the time-honored game of trying to estimate the market for space
tourism...  makes me nostalgic for the early days of the Shuttle
era...

There's a book review in the 11 December *Chicago Tribune*, on page 3
of the "Tempo" section, of a new book by a guy who paid $30,000 for a
tourist trip to the North Pole.  He rode on a Soviet icebreaker.
Sorry, don't recall the title or author.

My parents circled Mt. Everest in a jetliner, on a round-the-world
trip that probably cost them several kilobucks apiece.  How much would
it be worth to land there?

Presumably people would pay more to visit the wreck of the *Titanic*,
or maybe live on the ocean floor for a week or two.

     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
 /       \                          (_) (_)                    / | \
 |       |     Bill Higgins   Fermi National Accelerator Laboratory
 \       /     Bitnet:     [e-mail]
   -   -       Internet:  [e-mail]
     ~         SPAN/Hepnet:      43011::HIGGINS

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

Date: 12 Dec 92 13:27:45 -0500
From: [e-mail]
Subject: SSF Deputy Dir. Interview
Newsgroups: sci.space

          This is a short piece on an interview I had with Martin Kress of
          NASA.  I am sorry if it is not very good but I whacked it out
          when I should have been studying for finals.
          Thomas Freebairn

          SPACE STATION SAVANT SAYS NASA'S SEMANTIC SIZZLE SUCKS
          (so o.k.  I'm a sucker for sports headlines.)

          Recently Martin Kress, newly installed deputy director of Space
          Station Freedom, was in Indianapolis to participate as a panelist
          in the NASA town meeting.  He gave an interview to the Indiana
          University - Purdue University newspaper before the meeting
          began.

          Kress sat in the university hotel lobby, his words competing with
          the early morning vacuuming of the staff and institutional Muzak.
          Although he was living out of a suit case, many miles from home,
          Kress was impeccably dressed and seemed perfectly relaxed.

          While just beginning at his new post, Kress is no stranger to
          Washington or Capitol Hill.  Starting his career in Sen. Muskie's
          office, working on the Senate Budget Committee, he moved on to
          the Subcommittee on Science, Technology and Space.  Arriving at
          NASA in 1990 he was Assistant Administrator for Legislative
          Affairs before assuming the challenge of Space Station Freedom.

          "My beat has always been technology, budgets and policy," Kress
          said.  "Now my beat is technology, budgets, policy and running
          the damn thing."

          With all that time on the Hill, Kress knows all about the
          pitfalls the space station faces.  The Congressional budget cuts
          and the growing perception among scientists that Freedom will
          accomplish little, have not gone unnoticed.

          He believes that Space Station Freedom faces a three headed
          dragon.

          First is Congress and the budget.

          "When the Hill looks at an issue and they say, 'We have got to
          reduce the budget,' big is bad, by definition," Kress said.
          "They go through and look for big things.  They don't look for
          projects that may cost $5 or $10 million and are totally
          ludicrous.  They go after the big ones."

          The second is a lack of clear vision in Congress on if they want
          to go with big science and technology initiatives or with smaller
          more focused applied programs.  Kress feels this tension is a
          debate that has yet to be articulated in the halls of power.

          Third is the lack of a scientific constituency for the space
          station.

          "The science community that is going to benefit most from the
          space station is a new and emerging one," Kress said. "There are
          probably only 300 people in the life science and microgravity
          research fields right now in the United States.  I'm competing
          with 10,000 planetary scientists and astrophysicists for NASA
          funds."

          Yet he feels when NASA starts to announce funding for research on
          Freedom the science community will start to produce defenders,
          and not just critics, of the station.

          "All of a sudden we will have a built in constituency," Kress
          predicted.

          While not shy about speaking about Space Station Freedom, Kress
          seemed equally eager to discuss the town meetings and what NASA
          wanted and needed to accomplish with them.  He began by
          explaining a change in the format for the meeting that afternoon.

          The Indianapolis meeting was the first that the panelists did not
          open with a prepared presentation.

          "We went out and told people that we wanted to listen and
          interact with them but at six o clock when the meetings ended
          there was this long line of people that wanted to ask questions,"
          Kress said. "The way the format was working, we were talking too
          much and not listening enough.

          "I used to teach and I can look out into the audience and see
          when the eyes start to drift."

          Indeed the need to keep the American public's eyes from drifting
          was a recurring theme as Kress spoke.  This need is a relatively
          new phenomena for NASA, according to Kress.

          "Until the Challenger accident and some of the events of the mid
          80s, we really didn't have to go out and market ourselves or our
          programs," Kress said.  "We _were_ the standard.  Now we must
          really go out and let the people know.

          Yet he feels that NASA is not where it should be when it comes to
          communicating with the public.

          "We talk to millions and millions of people a year but for some
          reason we've not done a good enough job of telling the people
          what the value and the benefits are of the investment," Kress
          said.

           Some of the benefits he listed that were direct descendants of
          the space program were:
          - Cat-scans
          - MRIs
          - Fibulators
          - Computer miniaturization

          Some of the problems he sees with NASA communications are the
          over use of technical jargon and acronyms.

          "If you don't speak in common, simple English, who knows what
          you're saying," Kress said. "You can't say, 'I have a ASRM going
          to fly on a STS to launch the SSF.'  People look at you like,
          'Huh?'"

          Even before he started his new job at the Space Station project,
          Kress had begun his own campaign to lower the jargon volume.
          Last year he spent time with the public affairs staff and asked
          them to come up with a handbook in _English_.

          "I know it sounds crazy, but you're dealing with engineers,
          scientists and technical people and you're starting to understand
          each other, but nobody else does.," Kress said.

          This is an uphill battle.  Kress is working on NASA liaison with
          the Clinton/Gore transition team and has found himself rewriting
          70 percent of the print material returned to him after he
          requested they be made less technical.

          Kress would like to see a little English brought to NASA's video
          feed, too.

          "When you watch a mission on NASA Select, I would really like to
          see a narrator who is not a scientist or an engineer to give a
          narrative in simple terms," Kress said.

          In conjunction with this, Kress wants there to be an educational
          component with every NASA mission.

          "Have a curriculum for one year based on the missions we are
          going to do and bring the science back home," Kress said.  "Let
          the kids understand what we are doing and why we are doing it."

          He hopes that the town meetings are the first step in better
          communications between NASA and the public that ultimately holds
          its purse strings.

          "People have to know what it is you are doing before they are
          going to support what you are doing," Kress said.

          #30#


          Non-Journalistic Asides {NJAs}: All the people I met from NASA
          wore great suits.  Is there a NASA tailor hidden away somewhere?
          Special style kudos to Tyrone Taylor, NASA project manager for
          the town meetings.  As a grubby student journalist I found myself
          completely out-gunned on the sartorial flank. But, then again,
          that's been known to happen to me at the swine barn at the state
          fair.

          I liked Kress.  There was no lean forward and stare you in the
          eye, "Listen to me I'm a big shot" b.s.  He seemed very genuine.
          Not bad for a Notre Dame graduate.   

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

Date: 12 Dec 92 04:33:28 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

>True, a passenger version of the DC-1 couldn't carry more than
>about 20 people.  Of course, the Shuttle can only carry 7-10.
>What's your point?

  I missed what this discussion is about but the above needs a
  few qualifiers.
  DC-1 would only be able to carry 20 people if it used a special
  passenger module in the payload bay. If you built such a module
  for the Shuttle, you'd get alot more than 10 people in it. Maybe
  50 or so. Of course, *I* don't want a ticket in the thing.

  -Brian


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

Date: 12 Dec 92 04:32:51 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Titan IV
Newsgroups: sci.space

Looks like I blew it on the Titan IV in my last post (several days ago),
as one was launched on November 29, per Aviation Week and Space News.
That was Number 6. I never heard anything about it, and was mildly
surprised to read about it in this weeks AVLeak and Space News. It
got no attention from the media (to the USAF's delight, no doubt), not
even with the last military shuttle mission launched a few days later.

On the topic, does anyone know how much has been spent on Titan IV
since first flight? AvLeak shows launch costs at between 186-207 million
dollars, or about half what a Shuttle costs (being charitable and not
counting the kitchen sink at the KSC cafeteria). I'm curious how much
we have paid for Titan IV to launch six payloads versus how much we
paid for four times that number of Shuttle missions in the same
amount of time.

-Brian

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

Date: 11 Dec 92 18:36:00 GMT
From: Loren Carpenter <[e-mail]>
Subject: what the little bird told Henry
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] ("Phil G. Fraering") writes:
>>Hmm... every report that seems to come out says that the reason it's possible
>>now is because of the NASP materials research.
>
>>BUT: if the main place where NASP materials seem to be being used is
>>the heat shielding, and its re-entry temperature is lower than the
>>shuttle's, wouldn't shuttle re-entry materials be just as useful?
>
>They'd probably work as well, but there is a durability problem.  Having
>to inspect every last damned tile is the last thing you want to do for a
>vehicle that's supposed to have rapid turnaround.
>--

    Indeed.  I have an engineering sample of the white tile material.
    It has a color, density, hardness and stiffness similar to a fine
    grained foamed chalk.  At first it seems like a smooth styrofoam,
    firm and warm, but little white dust particles flake off as you
    handle it.  It would be easy to stick a pencil clear through a tile,
    though it would probably crack.  A moderate hailstorm would require
    replacing all of them.


        Loren Carpenter
        [e-mail]

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

Date: 13 Dec 92 00:49:32 GMT
From: Henry Spencer <[e-mail]>
Subject: what the little bird told Henry
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Mary Shafer) writes:
>Being success oriented is a wonderful idea if you're not depending on
>the developement of cutting-edge technology for your success.  The
>YF-22/YF-23 program was an outstanding example of how very well it
>works to be success oriented.  They were integrating elements that
>were somewhere between off-the-shelf and state-of-the-art into those
>aircraft.
>
>But suppose that they were depending on the timely development of
>several new technologies?  Maybe new engines _and_ new structural
>materials _and_ passive sensors _and_ flight control computers?
>Then every slip in every new technology would slip the program.

The answer to this one, of course, is obvious...  You need two separate
streams of activity:  the X stream, which pushes the edge of technology
and sometimes cuts itself when the edge turns out to be sharp, and
the YF stream, which builds production prototypes using technology whose
sharp edges are already known.  Trying to skip the X stage of the process
is attractive but doesn't work all that well (it's not for lack of trying,
either).

However, I think you can make a good case that projects in both streams
ought to be run on a "success-oriented" basis.  For the YF stream, as
Mary points out, it works extremely well.  And the X stream's job is not
to build things but to learn things, and ultimately you learn by making
mistakes... so best make them as quickly and cheaply as possible.  The
more time and money you spend trying to ensure that an X-stream project
won't fail, the more the project's cost/benefit ratio deteriorates.
(Maybe I'm just cynical, but I suspect we'd know more about hypersonic
flight if we'd flown the X-30 through X-35 as fast-track experimental
hypersonic craft, instead of spending ten years on the ground "preparing"
for an X-30 that will never fly.)  The X stream *will* have failures;
the stream as a whole needs to accommodate this, but the individual
projects should aim to succeed or fail quickly.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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End of Space Digest Volume 15 : Issue 541
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