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1993-07-13
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Date: Sat, 10 Apr 93 05:00:07
From: Space Digest maintainer <digests@isu.isunet.edu>
Reply-To: Space-request@isu.isunet.edu
Subject: Space Digest V16 #445
To: Space Digest Readers
Precedence: bulk
Space Digest Sat, 10 Apr 93 Volume 16 : Issue 445
Today's Topics:
** ACCESS to FTP site for images **
** FTP site for ASTRO images **
* SpaceNews 05-Apr-93 *
Aerospace companies cooperate in reusable vehicle market.
Blow up space station, easy way to do it. (2 msgs)
DC-X: Vehicle Nears Flight Test
Galileo Update - 04/08/93
Griffin / Office of Exploration: RIP
Mir 2's planned orbit [was Re: Degrees vs. experience] (2 msgs)
NASA "Wraps" (3 msgs)
NASP
nuclear waste
Question- Why is SSTO Single Stage
Shuttle Launch as Seen from North Carolina
The Area Rule
Vulcan? (No, not the guy with the ears!)
Welcome to the Space Digest!! Please send your messages to
"space@isu.isunet.edu", 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 space-REQUEST@isu.isunet.edu (Internet).
----------------------------------------------------------------------
Date: Fri, 9 Apr 1993 15:59:54 GMT
From: Frank ROUSSEL <rousself@cicb.fr>
Subject: ** ACCESS to FTP site for images **
Newsgroups: sci.space
SORRY !!! When the ftp server is full of anonymous users, it refused the access !
So try later...
------------------------------
Date: Fri, 9 Apr 1993 13:33:16 GMT
From: Frank ROUSSEL <rousself@cicb.fr>
Subject: ** FTP site for ASTRO images **
Newsgroups: sci.space
I commend everybody to look at the FTP site 'ftp.cicb.fr' (or 'ftp.univ-rennes1.fr')
-> Ethernet address 129.20.128.2 <- in the directory /pub/Images/ASTRO:
there are lots of images (all of kinds in astronomy subject) especially in GIF format
Note: this site is reachable by Gopher at 'roland.cicb.fr' (or 'roland.univ-rennes1.fr')
-> Ethernet address 129.20.128.27 <- in Divers serveurs Ftp/Le serveur ftp du CRI-CICB/Images/ASTRO
Hope you enjoy it !
------------------------------
Date: Fri, 9 Apr 1993 15:39:49 GMT
From: Darrell Haught <haught@tigger.jvnc.net>
Subject: * SpaceNews 05-Apr-93 *
Newsgroups: sci.space
------------------------------
Date: 9 Apr 93 10:04:57 PST
From: games@max.u.washington.edu
Subject: Aerospace companies cooperate in reusable vehicle market.
Newsgroups: sci.space
In article <C56Iq6.711@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes:
>> about studies of the potential commercial market deleted...
>
> This has been done repeatedly. The bottom line is very simple: the only
> customer whose volume of business is predictable with any certainty at all
> is the US government. All other major markets -- tourism, powersats,
> whatever -- are too small, too far down the road, or too uncertain.
> Otherwise it would have been done long ago, by Boeing if nobody else --
> Boeing doesn't *need* to talk to Wall Street to fund a billion-dollar
> project, not if the timing is right and the market is solid.
> --
> All work is one man's work. | Henry Spencer @ U of Toronto Zoology
> - Kipling | henry@zoo.toronto.edu utzoo!henry
Can you point me to these studies, I would like to get copies of them, and
read them for myself...
And, I still believe that what we are talking about has never been done.
Has anyone gone to hollywood, and found out just at what PRICE POINT, it
becomes desirable for them to start using space, as opposed to special
effects? Has anyone asked the advertizing agency for COKE, just EXACTLY
what it would be worth to put a 1 or 2 km inflatable coke can into orbit?
I think that we have a grip on what the tourism market can look like, the
Patric Q Collins study does a good job, and coupled with Pac Am Launch
sales, the figures seem to stand up, but there are other people with
potential uses, that they haven't even thought of, because the prices are
too high. But the point is, to find out AT WHAT PRICE POINT they get
serious about using space for those uses, and what kind of volumes they
will use at what price point?
I'll bet almost anything that there is a price point that would get the
WWF (World Wresteling Federation) interested enough to put money on the table
to televise a title grudge match in a special facility in LEO. (I used to
work for a company that almost got the theatrical lighting contract for
their tour, and we are talking BIG BUCKS here.)
There is BIG BIG bucks in advertizing, and entertainment, the question is,
at what price point do they get interested in giving space suppliers some?
There are literally over 100 conference facilities in the U.S. alone, with
conferences and trade shows going on all the time, that most people never
hear about. What is the price point where Miller Freedman (The owner of
many of the larger trade shows) becomes interested in moving the annual
xyz show to a facility in LEO? Bear in mind that it will be different for
every show. It will need to cost a lot less for the machine tools show,
but it might be able to cost more for the farming show, where better to show
off the new weather predicting and monitoring stuff.
Somebody needs to compile a list of every farfetched idea that has ever been
concocted for a use of LEO, and then get numbers for how much people would
really be willing to pay for that use, and what kind of volumes would be
associated with that price.
To my knowledge, this study or anything like it has never been done.
John.
------------------------------
Date: Fri, 9 Apr 1993 13:42:19 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Blow up space station, easy way to do it.
Newsgroups: sci.space
In article <AJB.93Apr8135953@ossa.dcs.ed.ac.uk> ajb@dcs.ed.ac.uk (Andrew Bissell) writes:
>> In article <1993Apr7.144426.15921@ke4zv.uucp>
>> Gary Coffman replies:
>
>> Your proposal is somewhat similar to the LLNL balloon station concept.
>> It is a cheap way to get large pressurized volumes. But most uses of
>> a space station require more than just a large pressurized volume.
>> Generally there will be requirements to host experimental equipment
>> and supply power for that equipment. You need structure for equipment
>> mountings, and structure for power systems. You need wiring channels.
>> You need storage lockers, etc. Also you need structure to allow reboost
>> burns against orbital decay. With a large pressurized volume comes a
>> large drag area that requires frequent reboosts. Without structures
>> to hold massive equipment and supplies in place, reboost becomes
>> difficult and dangerous. An open truss design gives lots of mounting
>> points without large drag generating surfaces. Most of the things a
>> space station is good for don't require large pressurized volumes.
>> Most space experiments want exposure to space conditions.
>
>
>The above points suggest to me the idea of placing the trus *inside*
>an inflatable structure, resulting in rigidity and anchoring points
>for equipment together with plenty of cheap volume around the truss for
>workspace and living accomodation. We can also integrate the station
>in a pressurised, controlled environment (it should be much easier to
>integrate truss sections when *not* having to wear a pressure suit).
>
>Perhaps this gets us the advantages of both approaches?
No Andrew, truss assembly is not a big issue, it's just plugging together
of a few prefab sections. A job for a remote manipulator arm. What you
want to avoid is large pressurized volumes because they add drag to the
station which requires costly reboost fuel. Your pressurized sections
should be the minimum necessary to support your experiments. Cans attached
to the truss structure. You want most of your station exposed to space.
Your solar arrays must be, many of your experiments want to be.
You need support structure for your life support and power systems
from the very beginning. Therefore you can't do any shirtsleeve
assembly until they are in place. This is chicken and egg for inflateable
structures. You can't work inside until you have support structures and
equipment installed for life support and power, and you can't install
structures in a shirtsleeve environoment until you can work inside. So
all that assembly has to be done in spacesuits anyway, so you might as
well do it outside where you don't have to worry about puncturing an
envelope.
Gary
--
Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary
534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244 | |
------------------------------
Date: Fri, 9 Apr 1993 17:01:35 GMT
From: "Allen W. Sherzer" <aws@iti.org>
Subject: Blow up space station, easy way to do it.
Newsgroups: sci.space
In article <1993Apr9.134219.7493@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>You need support structure for your life support and power systems
>from the very beginning. Therefore you can't do any shirtsleeve
>assembly until they are in place. This is chicken and egg for inflateable
>structures. You can't work inside until you have support structures and
>equipment installed for life support and power, and you can't install
>structures in a shirtsleeve environoment until you can work inside.
Not so for the LLNL Great Exploration station. It was packaged so that
it could be inflated and provide life support long enough for the
crew to do the remainder of assembly.
Allen
--
+---------------------------------------------------------------------------+
| Lady Astor: "Sir, if you where my husband I would poision your coffee!" |
| W. Churchill: "Madam, if you where my wife, I would drink it." |
+----------------------68 DAYS TO FIRST FLIGHT OF DCX-----------------------+
------------------------------
Date: Tue, 6 Apr 1993 13:17:16 GMT
From: Dave Stephenson <stephens@geod.emr.ca>
Subject: DC-X: Vehicle Nears Flight Test
Newsgroups: sci.space
nsmca@aurora.alaska.edu writes:
>Since the DC-X is to take off horizontal, why not land that way??
>Why do the Martian Landing thing.. Or am I missing something.. Don't know to
>much about DC-X and such.. (overly obvious?).
>Why not just fall to earth like the russian crafts?? Parachute in then...
The DCX takes off vertically. See the article in Spaceflight March 1993
page 90. The DCX carries a parachute, but only if something goes wrong.
The joke is that if you press the 'chute button, the next thing the
consol shows is the operator's resume and a list of openings at local
fast food outlets!
The russian craft use rockets for the final touch down.
--
Dave Stephenson
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: stephens@geod.emr.ca
------------------------------
Date: 9 Apr 1993 16:12 UT
From: Ron Baalke <baalke@kelvin.jpl.nasa.gov>
Subject: Galileo Update - 04/08/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Forwarded from Neal Ausman, Galileo Mission Director
GALILEO
MISSION DIRECTOR STATUS REPORT
POST-LAUNCH
April 2 - 8, 1993
SPACECRAFT
1. On April 5, a NO-OP command was sent to reset the command loss timer to
240 hours, its planned value during this mission phase.
2. On April 7, real-time commands were sent to modify the system fault
protection in preparation for the Radio Relay Antenna (RRA) slew test
scheduled for April 28. Specifically, a data table was modified to turn the
RRA motors off in the event of unexpected sequence termination.
3. On April 7, the Low Gain Antenna (LGA-2)/Dual Drive Actuator (DDA) hammer
mini-sequence was uplinked to the spacecraft without incident. This
mini-sequence covered spacecraft activities on April 8 and included three
deploy/retracts of the LGA-2 along with a DDA actuation window which began
immediately following the LGA-2 activity.
4. On April 8, under stored sequence control, the LGA-2 was deployed/retracted
three times beginning at 1052 PDT and completing at 1142 PDT. Immediately
following, real-time commands were sent to warm up the High Gain Antenna
(HGA) motors and to hammer the motors for 540 pulses at 1.25 hertz for a
33.3 percent duty cycle. Preliminary analysis of motor current data indicated
no change to the HGA configuration.
5. On April 8, a routine sun vector update was performed. This sun vector is
valid through May 30, 1993.
6. The AC bus imbalance measurement has not exhibited significant change
(greater than 25 DN) throughout this period but the DC bus imbalance
measurement has. The AC measurement reads 19 DN (4.3 volts). The DC
measurement has ranged from 151 DN (17.8 volts) to 63 DN (1.1 volts) and
currently reads 117 DN (13.6 volts). These measurements are consistent with
the model developed by the AC/DC special anomaly team.
7. The Spacecraft status as of April 8, 1993, is as follows:
a) System Power Margin - 69 watts
b) Spin Configuration - Dual-Spin
c) Spin Rate/Sensor - 3.15rpm/Star Scanner
d) Spacecraft Attitude is approximately 16 degrees
off-sun (lagging) and 7 degrees off-earth (leading)
e) Downlink telemetry rate/antenna- 40bps(coded)/LGA-1
f) General Thermal Control - all temperatures within
acceptable range
g) RPM Tank Pressures - all within acceptable range
h) Orbiter Science- Instruments powered on are the PWS,
EUV, UVS, EPD, MAG, HIC, and DDS
i) Probe/RRH - powered off, temperatures within
acceptable range
j) CMD Loss Timer Setting - 240 hours
Time To Initiation - 238 hours
UPLINK GENERATION/COMMAND REVIEW AND APPROVAL:
1. The EJ-2 (Earth-Jupiter #2) Cruise Plan was approved by the Project on
April 6, 1993. This plan covers spacecraft activities from July 6, 1993 to
August 27, 1993 and includes the IDA optical navigation images and the IDA
approach Trajectory Correction Maneuvers (TCMs) number 20 and 21.
2. The EJ-1 sequence memory load was approved for transmission by the Project
on April 8, 1993. This sequence covers spacecraft activities from
April 12, 1993 to June 14, 1993 and includes a window for the RRA slew test on
April 28, 1993.
GDS (Ground Data Systems):
1. Galileo participated in DSN (Deep Space Network) acceptance testing for the
DSN Telemetry Phase 3 Upgrade on April 1, 1993, from 19:00:00 to 23:00:00 GMT,
using CTA-21 (Compatibility Test Area 21). The purpose of this activity was
to test the flow of Galileo telemetry data through the new Telemetry Group
Controller (TGC) and the Telemetry Channel Assembly (TCA). The TGC/TCA
is the replacement for the current Telemetry Processing Assembly (TPA). The
test was started late due to the prior Voyager test running overtime. A TSA
(Telmetry Simulation Assembly) problem delayed the flow of data further, and
consequently only one telemetry rate was run (40 bps ESS) along with monitor
data. A retest is scheduled for April 13, 1993. MVT (Mission Verification
Test) of this system is expected to begin May 16, 1993.
TRAJECTORY
As of noon Thursday, April 8, 1993, the Galileo Spacecraft trajectory
status was as follows:
Distance from Earth 136,414,000 km (0.91 AU)
Distance from Sun 268,004,800 km (1.79 AU)
Heliocentric Speed 95,700 km per hour
Distance from Jupiter 555,761,800 km
Round Trip Light Time 15 minutes, 14 seconds
SPECIAL TOPIC
1. As of April 8, 1993, a total of 70177 real-time commands have been
transmitted to Galileo since Launch. Of these, 65070 were initiated in
the sequence design process and 5107 initiated in the real-time command
process. In the past week, 2484 real time commands were transmitted: 2484
were initiated in the sequence design process and none initiated in the real
time command process. Major command activities included commands to reset the
command loss timer, modify system fault protection, load the LGA/DDA hammer
mini-sequence, warm up and hammer the HGA motors, and update the sun vector.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Being cynical never helps
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/ |_|/ |_____|/ | and causes more aggravation
| instead.
------------------------------
Date: 9 Apr 1993 12:23:44 GMT
From: Dave McKissock <as806@cleveland.Freenet.Edu>
Subject: Griffin / Office of Exploration: RIP
Newsgroups: sci.space,talk.politics.space
In a previous article, jbh55289@uxa.cso.uiuc.edu (Josh Hopkins) says:
>yamauchi@ces.cwru.edu (Brian Yamauchi) writes:
>
>>Any comments on the absorbtion of the Office of Exploration into the
>>Office of Space Sciences and the reassignment of Griffin to the "Chief
>>Engineer" position? Is this just a meaningless administrative
>>shuffle, or does this bode ill for SEI?
>
>>Does anyone know what his new duties will be?
>
>The group examining the Freedom-based space station redesign proposals is
>headed by Michael Griffin, "NASA's cheif engineer" in the words of Space News.
>I believe this is him.
The Station Redesign Team, which is being lead by Bryan O'Connor (in
the absence of Joe Shea), has defined three option families, and they
have selected a team leader for each option family. The three option
families are:
Option A: Modular buildup. An expandable, modular concept. The
team is lead by Pete Priest.
Option B: Single Launch Core Station. Provides core station
capability in a single launch. This team is lead by Chet Vaugn.
Option C: SSF Derived. Uses current SSF elements to meet the
requirements of the redesign activity. This is the team lead
by Mike Griffin.
--
-----------------------------------------------------
dbm0000@tm0006.lerc.nasa.gov
------------------------------
Date: 9 Apr 93 07:39:33 EDT
From: Chris Jones <clj@ksr.com>
Subject: Mir 2's planned orbit [was Re: Degrees vs. experience]
Newsgroups: sci.space
In article <1q2sb7$f2b@access.digex.net>, prb@access (Pat) writes:
>ObSpace : The russians have made a formal offer to participate in
>Mir2, oh i mean space station ed. And pletesk is being upgraded
>to support Mir2 operations. Apparently, Mir2 will have a highly
>inclined orbit. 70 degrees or more, and pletesk is more effecient
>for that then Baikonur.
It's not clear exactly why the orbital inclination for Mir 2 has been changed
from the current Mir's 51.62 degrees to 65 degrees. One guess (which I tend to
believe) is that the Russian's are being cautious about depending on a launch
site outside of their country (Baikonour is in Kazakhstan). If they want to
use Plesetsk, which is in Russia, they have to increase the station's
inclination to efficiently use the payload capacity of the Proton launcher.
Since Proton launches have never been made from Plesetsk, there is work that
has to be done there to support Protons.
--
Chris Jones clj@ksr.com
------------------------------
Date: 9 Apr 1993 12:17:03 -0400
From: Pat <prb@access.digex.com>
Subject: Mir 2's planned orbit [was Re: Degrees vs. experience]
Newsgroups: sci.space
In article <24885@ksr.com> clj@ksr.com (Chris Jones) writes:
|In article <1q2sb7$f2b@access.digex.net>, prb@access (Pat) writes:
|>ObSpace : The russians have made a formal offer to participate in
|>Mir2, oh i mean space station ed. And pletesk is being upgraded
|>to support Mir2 operations. Apparently, Mir2 will have a highly
|>inclined orbit. 70 degrees or more, and pletesk is more effecient
|>for that then Baikonur.
|
|It's not clear exactly why the orbital inclination for Mir 2 has been changed
|from the current Mir's 51.62 degrees to 65 degrees. One guess (which I tend to
|believe) is that the Russian's are being cautious about depending on a launch
|site outside of their country (Baikonour is in Kazakhstan). If they want to
|use Plesetsk, which is in Russia, they have to increase the station's
|inclination to efficiently use the payload capacity of the Proton launcher.
|Since Proton launches have never been made from Plesetsk, there is work that
|has to be done there to support Protons.
|--
|Chris Jones clj@ksr.com
In Space News, they that is the director of Russias's civil Space agency
specifically denied that it was due to political tension with Kasakhistan.
That's a lot of money to provide proton support at Pletesk.
THe stated reason is that Mir2 will have a primary earth observation mission
and thus will be more efficient ina high inclination orbit.
I got the impression from the article that they were looking at 70
degree plus orbits. Maybe Dennis, our russo-phile knows more.
I think one big problem is they don't have progress handling
facilities at pletesk.
pat
------------------------------
Date: 9 Apr 1993 12:30:59 GMT
From: "David M. Palmer" <palmer@cco.caltech.edu>
Subject: NASA "Wraps"
Newsgroups: sci.space
sichase@csa3.lbl.gov (SCOTT I CHASE) writes:
>I believe that at all the National Labs, there is a Director's Fund,
>which is spent at his discretion. It is usually quite small, and used
...
>This is a good mechanism for (a) putting a few dollars into the hands
>of people on the scene, rather than relying on the Suits at DOE headquarters
>to identify all the interesting research proposals, (b) luring
>good people to the Directorship of a Lab, by giving them some direct
>control over the direction of at least a few research projects, and
>(c) building morale at the Lab by giving the Small People a way to
>get small amounts of money to work on projects which interest them even
>if they can't convince enough folks at DOE that they should fund it.
It is also good for faster, cheaper, better projects. If you have
to write a proposal and wait through a funding cycle before
you can start a small project which you can do in a month and
costs $10,000 then you aren't going to be very efficient
in terms of total science/man-year, or in timely results.
--
David M. Palmer palmer@alumni.caltech.edu
palmer@tgrs.gsfc.nasa.gov
------------------------------
Date: Fri, 9 Apr 1993 15:40:02 GMT
From: "Allen W. Sherzer" <aws@iti.org>
Subject: NASA "Wraps"
Newsgroups: sci.space
In article <1q25ko$6i1@usenet.INS.CWRU.Edu> as806@cleveland.Freenet.Edu (Dave McKissock) writes:
>I still don't see any evidence of Allen's point, though.
Call up Reston. Look at it this way, NASA says it will cost $2.25 or so
billion per year to build. Reston says $1.8B per year *IF* all the
money is spent on station and only station.
That leaves half a billion per year unaccounted for.
>Where are these billions of dollars that are allegedly in the
>SSF budget but are being "wasted" actually going?
I suspect a lot of it is going to pay for engineers working Shuttle and
other things besides Freedom. I doubt anybody does know, after all, there
usually isn't a nice line item for waste.
Allen
--
+---------------------------------------------------------------------------+
| Lady Astor: "Sir, if you where my husband I would poision your coffee!" |
| W. Churchill: "Madam, if you where my wife, I would drink it." |
+----------------------68 DAYS TO FIRST FLIGHT OF DCX-----------------------+
------------------------------
Date: Fri, 9 Apr 1993 15:45:02 GMT
From: "Allen W. Sherzer" <aws@iti.org>
Subject: NASA "Wraps"
Newsgroups: sci.space
In article <1q3qa3INNigh@gap.caltech.edu> palmer@cco.caltech.edu (David M. Palmer) writes:
>>I believe that at all the National Labs, there is a Director's Fund,...
>It is also good for faster, cheaper, better projects.
Agreed. I don't mean to say that wraps are always bad. Just here they
are costing too much money. What I think is hapenning is that people
see Station as a pile of $$ and they try and direct their work in
that direction to get the bucks. You see the same thing in Aids research
and any 'sexy' new technology.
Allen
--
+---------------------------------------------------------------------------+
| Lady Astor: "Sir, if you where my husband I would poision your coffee!" |
| W. Churchill: "Madam, if you where my wife, I would drink it." |
+----------------------68 DAYS TO FIRST FLIGHT OF DCX-----------------------+
------------------------------
Date: 9 Apr 1993 12:24:49 -0400
From: Pat <prb@access.digex.com>
Subject: NASP
Newsgroups: sci.space
It's been cancelled for spending a whole lot of money, taking
10 years, and never building any hardware. Oh and Mary said,
that they found out hte concept will never work anyway.
not enough energy in the cycle.
------------------------------
Date: Wed, 7 Apr 1993 20:07:46 GMT
From: Dave Stephenson <stephens@geod.emr.ca>
Subject: nuclear waste
Newsgroups: sci.space
gary@ke4zv.uucp (Gary Coffman) writes:
>fees, and the like.
>The only concern about oil products is the pollution produced by
>their use. Availability at reasonable prices is assured far beyond
>any reasonable projected timescale. The whole idea of importing
>hundreds of megatons of material a year from outer space is somewhat
>ridiculous. Eventually, there's no place left to put it.
Just a note about 'synthetic oil'. The syncrude Tar Sands plant produces
oil at somewhat less than $20 a barrel, and with current upgrades will
be doing it for less than $15. On the horizon are systems for extracting
light oils from heavy oil deposits and cracking them that might cost $12
a barrel. There is more hydrocarbons in the Alberta oil sands than in
the known reserves of light crude.
Energy that has to be imported from space has to be a) non-poluting
and B) comes from a low mass source (power beams or fusion) to hope
to be compeditive.
--
Dave Stephenson
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: stephens@geod.emr.ca
------------------------------
Date: Thu, 8 Apr 1993 13:03:23 GMT
From: Dave Stephenson <stephens@geod.emr.ca>
Subject: Question- Why is SSTO Single Stage
Newsgroups: sci.space
phoenix.Princeton.EDU!carlosn (Carlos G. Niederstrasser) writes:
> I would think that by applying all the concepts of SSTO to a double
>stager we would get nearly the same price and time performance, but with
>higher payload capabilities.
The point is that the IMPORTANT parameter is not payload fraction per
unit lift off mass, BUT payload fraction per unit lift off cost. Staging
is expensive. Fuel is cheap. Multi-stage operations are complex, ie.e
need lots of man hours to support them. SSTO is inherently more simple.
So what if the DCY burns more fuel. Provided the extra fuel is cheaper
than the engines structure etc. its money in the bank! I recommend
you read Max Hunter's article in JPAS Summer 1992. For light weight
structures (about 50% of shuttle) the advantage of staging is very small
in any terms
--
Dave Stephenson
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: stephens@geod.emr.ca
------------------------------
Date: Fri, 9 Apr 1993 14:42:04 GMT
From: Bill Goffe <bgoffe@seq.uncwil.edu>
Subject: Shuttle Launch as Seen from North Carolina
Newsgroups: sci.space,sci.space.shuttle
First, let me describe my observing site. I live in Carolina
Beach, a small beach town about 40 north of the border of North
and South Carolina. I have an unobstructed view to the east as
I live on the beach (which runs roughly north-south). Observing
to the southeast was hindered by the nearly full moon and its
reflection off the ocean (yeah, pity me). There were no clouds.
After watching the launch live on CNN for several minutes, I
went out on the balcony. After several more minutes, I saw a
moving light to the southeast, about 20 or 30 degrees off the
horizon, moving north at about the speed of a jetliner. With my
11x70 binoculars, it was clearly the shuttle as the exhaust was
quite obvious. I had the impression that the orange colored
exhaust was "bent" down.
In brightness, it appeared brighter than Jupiter, which is
currently putting on quite a display in the east after sunset.
A very rough guess would be magnitude -2 or -3 at its brightest.
I was able to follow it to the northeast until main engine cutoff
w/ the binocs (at some point it would have been hard, then
impossible, to follow by eye). After dimming for about a second,
it entirely disappeared.
_____________________________________________________________________
|Bill Goffe | Modems - what a great idea. They take the |
|bgoffe@seq.uncwil.edu | output of your digital computer, make it |
-----------------------| analog, send it to your phone company's |
|local office several miles away, where it is turned back into bits.|
|Support ISDN - two 64K & one 16K bits/sec channels. Pac Bell and |
|Bell Atlantic recently tariffed ISDN service at a flat $28/month. |
---------------------------------------------------------------------
------------------------------
Date: Fri, 9 Apr 93 12:33:18 EET
From: flb@flb.optiplan.fi (F.Baube[tm])
Subject: The Area Rule
From: George Hastings <ghasting@vdoe386.vak12ed.edu>
>
> (tom@igc.apc.org) writes:
> >
> > fluid becomes incompressible as you approch Mach Zero. as you
> > approach Mach One shock waves start to form; transonic or critical
> > yes, constant cross section (wings plus body) is optimal; so between
> > wing leading and trailing edges the body cross section must decrease.
>
> The idea is that
> you figure the frontal cross-sectional area of the body. Figure
> the frontal cross-sectional area of the wings. Then "scoop out"
> from the body just enough cross sectional area to equal the
> cross sectional area of the wings, right where the wings join
> the body, maintaining an equal frontal cross sectional area for
> the entire length of the aircraft.
Okay, I'm no rocket scientist, BUT ..
"Maintain an equal frontal cross sectional
area for the entire length of the aircraft"
-- this sounds like an airplane whose front end begins
and whose tail end ends with *flat plates*
-- not terribly aerodynamic I'd say
*Obviously* an airplane is shaped something like a
brontosaurus -- thin at one end; much, *much* thicker
in the middle; and thin again at the far end.
That was the point in my previous post -- the Area Rule
is also known as the "Parabolic Cross-Section Rule",
because (I surmise) a plot of
fuselage-cross-area as-a-function-of distance-along-length
is a parabaloid.
But obviously NOT a straight line, as the cited posts imply.
my kaksi pennia worth, kiitos
--
* Fred Baube (tm) * In times of intellectual ferment,
* baube@optiplan.fi * advantage to him with the intellect
* #include <disclaimer.h> * most fermented
* How and what is Frank Zappa doing ?
* May '68, Paris: It's Retrospective Time !!
------------------------------
Date: Mon, 5 Apr 1993 16:41:04 GMT
From: Dave Stephenson <stephens@geod.emr.ca>
Subject: Vulcan? (No, not the guy with the ears!)
Newsgroups: sci.space
neff@iaiowa.physics.uiowa.edu (John S. Neff) writes:
>>Does anyone have any info on the apparent sightings of Vulcan?
From memory Vulcan was an attempt to account for the precession
of the axes of the orbit of Mercury in the late 19th century. The
effect has now been full explained thanks to the Theory of
Relativity. In fact Mercury's orbit was one of the first
confermation of relativity. Vulcan was supposed to have been
observed by a somewhat dubious 'gentleman' astronomer who kept
his notes on a plank of wood, and used plane as an eraser.
--
Dave Stephenson
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: stephens@geod.emr.ca
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End of Space Digest Volume 16 : Issue 445
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