Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO540.TXT

Internet Message Format | 1993-07-13 | 34KB

Date: Sun, 13 Dec 92 05:04:04
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #540
To: Space Digest Readers
Precedence: bulk


Space Digest                Sun, 13 Dec 92       Volume 15 : Issue 540

Today's Topics:
                                AmRoC
              Cassini Undergoes Intensive Design Review
                               DC info
                      DC vs Shuttle capabilities
                           DoD launcher use
                               Jet Lag
                      Magellan Update - 12/11/92
                     NASA Select mission coverage
         One Small Step for a Space Activist... (vol 3 no 12)
                            Space Tourism
                      SSF Deputy Dir. Interview
       Terminal Velocity of DCX? (was Re: Shuttle ...) (3 msgs)
               what the little bird told Henry (2 msgs)

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 12 Dec 92 19:56:25 GMT
From: George C Harting <[e-mail]>
Subject: AmRoC
Newsgroups: sci.space

Hello out there...

    I was wondering if anybody had any recent info about Amroc's Hybrid
rocket?  Perhaps even hybrid rockets in general...
    Personally, I like the company's philsophy of building a rocket with
a true commercial market in mind - i.e. no pork barrel government money for
development and started independently.
    However, it seems that they have always been running into
problems trying to get their design to work (I think only one successful test
of the 75Klbf engines ever worked).  And they have never had an actual launch!
    Anyway,have hybrid rockets ever been used?  I heard that they may have
been for small missiles but nothing as large scale as Amroc's.

                    George

I have no friggin' .sig!

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

Date: 11 Dec 92 16:56:09 GMT
From: Steve Flanagan <[e-mail]>
Subject: Cassini Undergoes Intensive Design Review
Newsgroups: sci.space

[e-mail] (Hayim Hendeles) writes:

>In article <[e-mail]> [e-mail] 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! 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).

Cassini would love to be able to launch on a direct trajectory to Saturn,
or launch directly to Jupiter and use a gravity assist to get to Saturn.
This is not possible due to the launch energy requirements of these
trajectories.  The launch vehicle currently baselined for Cassini, the
Titan IV/SRMU/Centaur, can launch our total wet mass of over 5800 kg with
a maximum C3 (launch V-infinity squared) of ~22 km^2/s^2.  Compare this to
the minimum C3 needed to reach Jupiter or Saturn directly (~83 for Jupiter,
~108 for Saturn for '97 launch) and you can see why we need to use indirect
trajectories.

Steve Flanagan
Cassini Mission Design Team
[e-mail]
Standard disclaimers apply.

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

Date: 11 Dec 92 16:44:47 GMT
From: "Michael F. Santangelo" <[e-mail]>
Subject: DC info
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

>In article <[e-mail]> [e-mail] (Michael F. Santangelo) writes:
>>  I'm real foggy from this description as to what the RL200 engine is
>>going to be.  Is it a name for many RL10-A5's grouped together through
>>a common master nozzle of some form?  Or is it a seperate engine system
>>used to augment the RL10-A5's on the latter DC systems during flight...?

>No, it's a new engine, with some RL10 design heritage, relying on bits and
>pieces that mostly have been tested already.  Only DC-X (and the proposed
>DC-X' suborbital flyer) will use RL10s at all.  It's an excellent engine,
>but a bit small for the full-scale DC-Y.

(Allen & Henry- thanks for the initial followups to my question)

  How different will the RL200 be from the RL10-A5's used on DC-X?  Is
it simply a scaled up version of the same (RL10).
  Better way to do this would perhaps be to post the (proposed) thrust, isp,
etc specifications of the RL200 beside that of the RL10-A5 in a table.

Allen Sherzer writes:
>It is a separate engine which will be used for DC-Y if built. Some of the
>RL-200 engines will have extendable nozzles and will be sustainer engines
>for DCY and others will have non-extandable ones and will be used as
>boosters. Except for the nozzles, they will be the same.

  How many RL200's would be used on the DC-Y/DC-1 designs?
  Boosters?  on DC?  I take it normal LEO operations would not require
booster RL200s, but is this sort of a strap-on capability for larger
payloads and/or more demanding orbital inclinations?

--
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Michael F. Santangelo                 + Internet: [e-mail]
Computer & Network Systems Director   +           [e-mail]
UMCEES / CBL (Solomons Island)        + BITNET:   MIKE@UMUC
University of Maryland                + Voice:    [phone] (direct)
                                      +           [phone] x237

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

Date: Fri, 11 Dec 92 16:39:43 GMT
From: Doug Mohney <[e-mail]>
Subject: DC vs Shuttle capabilities
Newsgroups: sci.space

In article <3kf2v=[e-mail]>, [e-mail] (Michael V. Kent) writes:
>In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>
>>In article <[e-mail]> [e-mail] (Michael V. Kent) writes:
>
>>>Here's a question that just popped into my head:  Would a modified Spacehab
>>>(note the "h") module fit in the cargo bay of the Delta Clipper?
>
>>Why not just make it a module on the space station?
>
>I'm thinking more along the lines of modifying it into a man-tended free-flyer.
>Delta Clipper's projected 2-day on-orbit time is too short for Spacehab
>work, especially if you have a space station.  There are some experiments
>that would benefit from man-tended operations instead of space-station
>operations.

Umm, your better bet would be to launch your thingy on a unmanned expendible
(you pick 'em, probably Allen's much vaunted Titan IV or Delta-whatever). Or an
uprated Ariane, depending on how much working space/mass you wanted to lift,
and how competitive the bids are.

Or go over and waive some money at the Russians, get them to send up some
surplus hardware they have laying around.

DC-1, ***IF*** it lives up to its promise, opens up the doors for some of the
bigger industrial conglomerates to (if they need/want it) send up their own tin
cans for experimentation purposes. Or to rent space on Mir and access it at
their own place.

The Henry Spencer Industrial Space Park, anyone?

                :-)

                 Play in the intelluctual sandbox of Usenet

  -- >                  [e-mail]                        < --

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

Date: 11 Dec 92 20:40:50 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: DoD launcher use
Newsgroups: sci.space

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

>>The current head of Space Command ran the air war against Iraq and was
>>hampered by lack of access to satellite images. A vehicle with DC's
>>turnaround time is just what he needs.

>This puzzles me somewhat. DC would allow a short notice launch of a LEO
>satellite, but such satellites have very short, and fixed, looks at a
>given combat theatre. If would seem to me that recon aircraft are still
>a better choice for tactical recon.

for many applications satellite is better. Recon aircraft are too easy
to shoot down (especially when doing Bomb Dammage Assessments). In addition,
every aircraft in the theatre needs services for takeoff, landing, refueling,
jamming, defense suppression, ATC, fighter cover, and others. Every recon
sortie you fly looses you a sortie for CAP, bombing, or whatever. In
addition, satellite images can be made available sooner and are far fresher
than photos taken from aircraft.

Aircraft DO have a role but rapid satellite deployment will make your air
force a LOT more productive.

>Using DC itself as a recon platform
>seems like serious overkill,

Not DC itself. DC simply launches the satellite.

>but then the military always likes overkill I suppose.

Sometimes. But then so would you if it was YOUR ass on the line getting
shot at.

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------134 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Sat, 12 Dec 92 16:27:20 EST
From: John Roberts <[e-mail]>
Subject: Jet Lag

-From: [e-mail]
-Subject: Jet Lag
-Date: 11 Dec 92 22:29:44 GMT

->I believe you have that backwards.  My understanding is, the faster the
->flight, the less the jet lag.

-Think about it.  If you take a tramp steamer, the difference between your
-local time and POD time is very small, per unit of travel time, so you
-can catch up on the difference as you go.  The faster you travel, the
-bigger is that difference, and the less time, during travel, you have to
-keep in-phase.

I think I tend to agree with Henry's view (that faster travel shouldn't
have a negative effect on time adaptation), with the following provisions:

# Henry's approach requires that you spend a day or more either before or after
  the flight to adapt your schedule. In theory that makes sense, but in
  practice it is likely to take considerable mental discipline (which Henry
  has, no doubt, but I'm not so sure about the rest of the population).
  Before the trip, you're busy getting ready, taking care of last-minute
  details, etc. And if you have limited vacation time, it might seem silly
  to take an extra day of leave just to stay at home sleeping during the
  day. Once you get to your destination, the natural incliniation is to
  rush around doing things, rather than "waste" a day sleeping. A longer
  travel time *forces* you to start adjusting (with various unpleasant side
  effects, as Henry pointed out).

# Many people tend to wake up at local dawn, regardless of how much sleep
  they got. So it might be necessary to put black paper over the bedroom
  window in order to adjust properly.

# Humans are really only efficient at adjusting their sleep cycles forward -
  it's much easier to stay up a little later and sleep a little later than to
  go to bed earlier and get up earlier. So if the direction of travel is such
  that backward adjustment is required, the fatigue brought about by sitting
  for many hours in an uncomfortable seat might help you to sleep when you
  ordinarily would not. But I wouldn't say that this is a real benefit of
  prolonged travel time - it's more a *perceived* benefit.

John Roberts
[e-mail]

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

Date: 11 Dec 92 22:19:49 GMT
From: Lord Vader <[e-mail]>
Subject: Magellan Update - 12/11/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary

To Ron Baalke:(or anyone else who knows)

re:

>1.      Magellan continues to operate normally, transmitting a carrier plus
>40 bps X-band signal which is precisely tracked by the DSN (Deep Space Network
>stations to provide gravity data.

>2.      The present command sequence is designed to automatically shift the
>telemetry to the 1200 bps rate if the tracking pass is over a 70 m
>station, based on the DSN station allocation schedule as of the time
>the reference file was prepared.  In the event the station assignment
>is changed, some telemetry may be lost because the 34 m stations
>cannot successfully receive the 1200 bps rate due to the Transmitter B
>noise spur.

Which DSN stations are 34 m and which are 70?  Also, do some of the DSN
stations have the capability to recieve S-band and X-band at the same time,
and if so, which ones?  And, who can I contact to get the parameters of
the individual DSN stations and the entire DSN capabilites?

I understand that Magellan has limited capability to transmit engineering
data over the X-band transmitter due to the noise spur in the subcarrier.
Is this data then being transmitted via the s-band, and if so, like I asked
above, is it being recieved at the same time as the x-band gravity data,
or does it have to be recieved separately due to limited ground capabilities?

Mike

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

Date: Sat, 12 Dec 92 16:09:21 EST
From: John Roberts <[e-mail]>
Subject: NASA Select mission coverage

-From: [e-mail]
-Subject: SSF Deputy Dir. Interview
-Date: 12 Dec 92 18:27:45 GMT

-          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

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

-          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.

They did a very good job of that on STS-53 - the acronyms and the projects
they represented were explained many times.

Another innovation was text periodically placed on the screen reading
"next mission summary at <time>". This was very useful, because I typically
leave the VCR recording when I go to work, and play it back in fast-forward
mode, looking for the interesting parts. What would *really* be ideal would
be text reading "voice originating from Mission Control" while the summary
is actually going on - that way, those of us who use a VCR to scan mission
coverage could scan at the maximum rate, looking for that graphic.

John Roberts
[e-mail]

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

Date: 12 Dec 92 21:58:11 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: One Small Step for a Space Activist... (vol 3 no 12)
Newsgroups: sci.space,talk.politics.space

           One Small Step for a Space Activist...
                Vol. 3 No. 12 - December 1992
                             By
                  Allen Sherzer & Tim Kyger

The Freedom Space Station project is at it again. Two stories
have recently surfaced which once more call the future of this
project into question.

First, is a Space News story about the progress (or lack thereof)
in Work Package 02 (the truss structure) of SS Freedom. In Dec.
1987 NASA awarded a $1.8 billion contract to McDonnell Douglas.
Nine months later when the final contract was signed, the price
had gone up to $2.6 billion. Four years later, as a result of cost
overruns, Work Package 02 now weighs in at $4.9 billion -- A 250%
increase during a time when funding and design for Freedom was
relatively stable. To pay for these overruns NASA has had to dip
big time into its reserves, which will cause even more damage later
in the program.

Worse yet, Work Package 02 is as much as 18 months behind schedule.
McDonnell Douglas recently informed NASA that it can provide only
700 of the 2,700 drawings promised before the next design review.
This action (or lack) will ripple down the PERT charts and could add
up to billions more in cost overruns as other contractors are forced
to mark time waiting for Work package 02's outputs.

Congresses' fault? Not this time. Most of the overruns and delays
have happened at a time when Freedom has seen very stable funding and
little design interference.

The second problem looming is more ominous and insidious. For a long
time the Johnson Spaceflight Center (JSC) has been trying to shut
down the Reston Virginia Space Station Program Office and move it to
Houston. The recent creation of a contractor-led integration team at
Johnson called the Joint Vehicle Integration Team (we never knew
Freedom was a vehicle - did you?) may accomplish keeping the Reston
office in existence, but doing nothing, and moving all other space
station efforts to Johnson.

JVIT, like many things, sounds like a great idea -- at first. It
would make the contractors responsible for the overall space station
project which is something many space activists have always felt was
needed. It would also tie fees to contractor performance, which is
also something desperately needed inside NASA. On the other hand,
is it appropriate for THIS project? The last time the integration
task was moved (for the creation of the Reston office) it resulted
in massive program slips. How can moving the integration task to
Johnson be anything but disruptive? Can the program afford
disruption now?

Worse, the people responsible for integration haven't done
all that good a job to date. JVIT will make it far easier
for both NASA and contractors to hide overruns and provide
the appearance of progress where none exists.

These new massive cost overruns and NASA's inability to control
them, along with the JVIT, which turns integration over to the
people responsible for the whole mess, should make one wonder
what the goal of this project is. Is the goal a permanent
outpost for Americans in space or is it to spend $2 billion
every year on whoever has the political clout to bring to
the pork home? It appears more and more to us that the goal is the
latter. As Dick Jones, VP, Omni Consumer Products put it:
"Upgrades, renovation programs, spare parts for 25 years;
who cares if it works or not!"

                     Legislative Roundup

                          SSTO/SSRT
Freshmen Orientation, a project to brief ALL new
Congresspersons on SSTO, is progressing well. To date about 100
training packets have been mailed to local activists and
most should have sent out letters requesting meetings by
now. Kudos to Larry Ahern, NSS Chapters Coordinator, who is
meeting with a Chicago area Frosh staffer in early
December. If you want to help, contact Tim Kyger at (202)
225-8459.

                      Commercial Space
The start of the 103RD Congress is near. Time again to
continue the process of chipping away at government
impediments to commercial space activity. Expect to see some of the
tax provisions which didn't make it into last year's NASA
bill to be re-introduced. If Clinton is serious about
targeted tax cuts to promote investment then odds of
passage, even if only as an amendment may be pretty good.
Activists have been very successful with this in the past
few years (pats on the back all around and several directed
at San Diego); let's all keep up the good work.

Also upcoming is the Lunar Resources Data Purchase Act. This
is a great idea for legislation we will discuss in detail next
month.

Thing to do:
1. Do you have any ideas on what would be good to include in
future commercial space legislation? If so, drop a note to
Barry Berringer, Care Of Rep. Robert Walker.

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------133 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 12 Dec 92 00:05:36 GMT
From: Mary Shafer <[e-mail]>
Subject: Space Tourism
Newsgroups: sci.space

On Fri, 11 Dec 1992 21:23:21 GMT, [e-mail] (Josh 'K' Hopkins) said:

J> Right.  There was an Air & Space article on this a number of years ago.  They
J> also carried the original add in their first issue - quite an eyecatcher.  As
J> I recall there were something like 350 people who put down $500 deposits on a
J> $52,000 flight.  I think they were eventually refunded but I'm pretty sure
J> that they were supposed to be non-refundable.  So, if 350 people will pay
J> $52,000 for a vehicle that isn't flying and isn't all that heavily advertised
J> I think we can assume that this price will provide a big enough market for
J> space tourism.  The next question is how much higher it can get before the
J> market dries up.  Is there any other data out there?  What's the maximum that
J> real people pay for really cool Earth-bound trips?  Anyone ever priced a trip
J> to Antarctica?

My husband and I each paid $3,000 to go to the Patriot Hills in
Antarctica, on a DC-6 from Punta Arenas.  The folks on the plane who
went on to the pole paid $20,000.  It's a lot cheaper to just go
to the shore by boat, but we went deep into the interior.

--
Mary Shafer  DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA
[e-mail]                    Of course I don't speak for NASA
 "A MiG at your six is better than no MiG at all."  Unknown US fighter pilot

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

Date: 12 Dec 92 08:59:45 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: SSF Deputy Dir. Interview
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] writes:
[interesting interview with Marty Kress deleted]
>
>           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.

I disagree.  You were wearing your pants decorated with a pattern of
chili peppers that day.  I thought you cut a fine figure.  My
compliments to your tailor.

>           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.

We ND graduates are everywhere.  But some of us have better suits than
others.

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

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

Date: 11 Dec 92 19:33:02 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:

>It's amazing that things we did routinely in the 1960's are considered
>challenging today.  I guess we've lost a lot of technology since then,
>right?

It's not that so much as we have become too timid and risk adverse.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------134 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Fri, 11 Dec 1992 16:50:27 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

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

>Titan IV is turning into a bigger hanger queen than Shuttle ever
>was, DC-1 is a paper airplane, etc. A more intelligently designed
>spacecraft is badly needed to replace Shuttle, but the DC program
>isn't it.

Interesting.  DC-1 isn't a viable replacement for the Shuttle
because it's a "paper airplane."  Of course, any new design
will be a "paper airplane."  If we reject every design before
it's even built, we'll never have a replacement.

>It may be *part* of a fleet of specialized vehicles that
>replace Shuttle, but it can't do many of the things that Shuttle
>is capable of doing,

No space vehicle is capable of doing all the things the Shuttle
is capable of doing (in theory).  Trying to design a single launch
vehicle capable of satisfying every possible user and every possible
mission is as ridiculous as designing a single "national airplane"
capable of carrying out every military and civilian air mission.


>lifting large payloads,

Most large payloads are not solid chunks of metal.  They are assemblages
of smaller parts.  If the cost of space transportation drops far enough,
it will become feasible to assembly some of those pieces in space. That
reduces the need to carry large payloads.

>carrying large crews,

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?

>support Canadarm,

I don't really see why not, as long as the arm can be folded to
fit the DC's cargo bay.  Of course, a man in a space suit is more
versatile than Canadarm and, if the transportation costs are low
enough, cheaper too.


>Compare SSTO to Proton, the payload capacities are similar. SSTO has
>to beat Proton costs and reliability to be a success. $300 a pound
>is a difficult target. Of course CIS prices are likely to increase
>once the fire sale is over.

Why?  I can buy a ticket to Australia for $1100.  With my luggage,
I weigh well over 200 pounds.  That's less than $5.50 a pound.

It takes less energy to put a pound of payload into orbit than
it does to fly it through the atmosphere to Australia. Why should
it be difficult at 60 times the price?

There is a common view, nothing more than a technological superstition,
that space transportation must be hideously expensive because rockets
are so complex.  But a rocket engine is conceptually much *simpler* than
a turbojet.  There is no reason it should cost an order of magnitude
more to build and operate.

This view, I think, comes from watching too many films of rockets
blowing up on the launch pad or climbing majestically into orbit,
dropping stages, etc.  But the cost and performance record of
converted long-range artillery rockets tells us little or nothing
about true space-transportation systems.


>X plane data has been incorporated into
>several high performance system designs, but they don't look or work
>like the X plane at all. I don't expect any DC-1 to look like a scaled
>up DC-X either.

Okay, if it pleases you, Gary, stop thinking of the DC-X as an X-plane.
Instead, think of it as the equivalent of Burt Rutan's subscale prototype
of the Beech Starship.  Got it?



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

Date: 11 Dec 92 17:28:26 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

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

>In article <[e-mail]> [e-mail] (Edward V. Wright) writes:

>>The engines used by every commercial airliner were "radically new"
>>and "never flight tested" at one time also.  Despite your claims
>>of "radicalism," the rocket engines are little different from those
>>we have been building for more than 40 years.  They are a new design,
>>not a new technology.

>Yes, they are basically a *new* design despite being based on the
>proven RL-10. Adding throttleability to a rocket engine isn't simply
>a matter of adding a valve.

By that logic, every jet-engine design is a "radically new technology."
This "isn't trivial engineering that can be brushed aside by saying
it's been done before with other engine designs... It *should* work,
but they won't know until they try it what problems may develop."  For
some reason, I don't see airliners falling out of sky because of the
"radically new" engines that are introduced, quite regularly, every
few years.


>>>Later it intends to use aerospike engine designs that have
>>>*never* been tested, even on the ground.

>>Really?  On what do you base this statement?  The designers
>>at McDAC have repeatedly stated that they do not plan to use
>>an aerospike.

>The aerospike is the alternative design if the variable expander
>doesn't work out.

Oh?  Well, then, it doesn't sound to me like they "intend to use [it]."
However, aerospike engines were built and tested as long ago as the
1960's.  Suffice it to say that your conception of what is and is
not "radically new technology" is 30 years out of date.


>>Saying that doesn't make it so.  The engine is about as "radically
>>new" as a new microprocessor.  The control problem is the same one
>>that was solved, for ICBMs, in the 1960's.

>That's funny, I didn't know ICBMs did controlled powered landings. I
>thought they used ballistic re-entry vehicles atop a multistage suborbital
>rocket.

Oh.  I thought you were talking about the reentry.  No, the controlled
powered landing was demonstrated, again in the 1960's, by a vehicle
called the LEM.  Which had the additional requirement of landing solely
in unprepared fields.

It's amazing that things we did routinely in the 1960's are considered
challenging today.  I guess we've lost a lot of technology since then,
right?

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

Date: 11 Dec 92 19:36:06 GMT
From: Mary Shafer <[e-mail]>
Subject: what the little bird told Henry
Newsgroups: sci.space

Organization: NASA Dryden, Edwards, Cal.
In-Reply-To: [e-mail]'s message of Fri, 11 Dec 1992 17:56:29 GMT
Lines: 40
Source-Info:  Sender is really [e-mail]
Source-Info:  Sender is really [e-mail]

On Fri, 11 Dec 1992 17:56:29 GMT, [e-mail] (Edward V. Wright) said:

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

>They're also heavy as I recall, something you don't need in a SSTO.
>I appreciated the summary you gave earlier, Henry. It looks like they
>have a better test program planned than what has been outlined here
>before. I still think their schedule is extremely optimistic and
>success oriented, but we'll see.

D> I'd be curious to know the exact date, sometime in the last 20 years,
D> when "success oriented" became a pejorative phrase.  Yeah, the project
D> is success oriented.  Just like Project Apollo.  The alternative, I
D> guess, is for a project to be "failure oriented."  I like success better.

I can't tell you the exact date, but I can assure you that it happened
some time during the "success-oriented" Space Shuttle program.

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.
And by assuming that each development effort will be completely
successful and timely, you've guaranteed that you have absolutely
no fallback position.  If you've specified the weight of the
aircraft based on the thrust of the unsuccessful engine, you're
stuck (a fairly common event, by the way).


--
Mary Shafer  DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA
[e-mail]                    Of course I don't speak for NASA
 "A MiG at your six is better than no MiG at all."  Unknown US fighter pilot

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

Date: 11 Dec 92 17:51:00 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: what the little bird told Henry
Newsgroups: sci.space

In <[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.

That's marketing speak.  In fact, Phil Bono at (what was then) Douglas
Aircraft studied SSTO designs during the 1960's and concluded it was
possible with the technology available then.  Of course, new materials
make it easier today, and McDAC will (over)emphasize that in their
marketing brochures to make the project sound exciting and high-tech.


>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 would be overkill.  The DC isn't as heavy as the Shuttle, so
it wouldn't get as hot.  Besides, the shuttle's heat shielding has
been a maintenance nightmare.

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

End of Space Digest Volume 15 : Issue 540
------------------------------