Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_3/V16NO304.TXT

Internet Message Format | 1993-07-13 | 36KB

Date: Fri, 12 Mar 93 05:29:13
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #304
To: Space Digest Readers
Precedence: bulk


Space Digest                Fri, 12 Mar 93       Volume 16 : Issue 304

Today's Topics:
                 20 kHz Power Supplies "blowing up"!
                      Bullets in Space (2 msgs)
                      Galileo Update - 03/11/93
       Lawsonomy (was Re: ALTERNATIVE Comet Rendezvous Mission)
                         Lunar Ice Transport
                    Moons rotation period question
                            More on LRDPA
                          Rocket Propulsion
                     SR-71 Maiden Science Flight
                 Winding trails from rocket (3 msgs)

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

Date: 11 Mar 93 17:10:08 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: 20 kHz Power Supplies "blowing up"!
Newsgroups: sci.space

Article-I.D.: mksol.1993Mar11.171008.1926
References: <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]>
Organization: Texas Instruments Inc
Lines: 147
Sender: [e-mail]
Source-Info:  Sender is really [e-mail]

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

>In article <[e-mail]> [e-mail] (David B. Mckissock) writes:
>>In article <[e-mail]>, [e-mail] (Pat) writes...
>>>
>>>Unless you were some sort of demi-god there,  don't expect to
>>>hear every story in the program.
>>I worked in a System Engineering organization at the time,
>>and our job was to help pull together the *ENTIRE* story
>>concerning the SSF power distribution frequency. We
>>worked closely with the other work packages, the Internationals,
>>and Level II. It was our job to hear *EVERY* part of the story

>There were still numerous people in Management whose job was to
>not hear problems, but to roll the schedule.

So your contention here is that someone who was there and cognizant
must know less than someone like you who was not?  This logic is as
interesting as that of 'anonymous poster' about how it takes more
courage to *not* be associated with what you say.

>>relative to the decision. My guess is that your Reston
>>contact was outside the loop on the 20 kHz decisions, and
>>heard spurious rumors.
>><< Discussion attacking 20 kHz deleted >>

>Not how you avoid a very resaonable discussion on how STUPID
>the 20 KHz idea even was in the first place?

>Can you name any competent Electrical engineers, or Computer engineers
>or PE's  who thought this was a good idea?

Gee, Pat, do you think an accountant dreamed it up, or what?
Obviously there were some engineering folks who thought it *might* be
a good idea, or it would never have been investigated in the first
place.  This is how engineering works, Pat.  You look at various
possible solutions to the problem, analyse the risks, costs, and
benefits, and then you pick the one that seems best overall.

>Given how bad the concept of 20 KHz was,  why do you expect me to believe
>the studies on it's safety.

Because he was there and you weren't?  This starts to sound more and
more like a "my mind is made up -- don't cloud the issue with facts"
position on your part.

>Name 5 advantages to 20 KHz.  I dare you.

Gee, now *there* is an adult discussion.  Hey, see if you can find
some and broaden your own mind.  I *double* dare you!

>Name 5 disadvantages to 20 KHz.  Compare and assess these.

>Now justify all the money spent on the 20 KHz power project.

>>
>>>Sorry, quoting some rag of documentation doesn't impress me.
>>The 'rag' of documentation I quoted from is the Program
>>Definition and Requirements Document, referred to as the
>>PDRD or SSP 30000. For anyone working on SSF, this document
>>*IS* the Holy Bible.
>>

>BIG DEAL.
>The system requirements document.  I've seen requirements documents
>on lots of projects.  ANd if the document is poorly done, it doesn't
>matter.  If the people doing the work don't care about quality
>it doesn't matter.

>It's just more paper and vapor.  You guys have spent a lot of money,
>and don't have much product to show.

Once again, you seem to think you know better than someone who was
there and has seen the things.  That's not to say that there aren't
problems; I would say there most certainly are, from what I've seen.
However, I think you'd be better served to address the problems
instead of random flames.

>>You obviously don't understand how NASA operates. For the SSF
>>program, NASA has three Contractors responsible for building
>>SSF hardware (McDonnell Douglas, Rocketdyne, and Boeing). A

>And who is responsible for integrating their work?  How come
>that's a major management issue?

Bingo!  Real problem #1.

>>At each design review, the Contractor must provide evidence
>>that their design meets each and every requirement. In

>And how rigorous does that evidence have to be?  do any
>PE's stamp off  the designs?

I would say that, in general, no.  Who made a PE ghod?  There are lots
of good engineers who simply can't be bothered with it, since it is
only in things like structural engineering that it becomes
particularly meaningful.  I've always found it funny that, except for
stuff that delivers to the government (which follows more reasonable
rules about who is an 'engineer'), I would have to get a PE to sign
off on a software system when there is no such thing as a PE for
software engineering.  What that means is that someone who is
specialized in a different field has to sign off on the software.
Does this strike you as ridiculous?

>>any areas where the design doesn't meet the requirement, a
>>deviation or a waiver must be processed.
>>
>Or a smoke cloud is generated.

>>This whole area of requirements verification is treated
>>very seriously.

>As serious as the budget over-runs?  i don't think so.

Then you've never been through a requirements audit.

>Basic engineering criteria and design decisions were made for SSF
>on fatally flawed reasoning.  all the paper in the world won't
>make up for those mistakes.

>I dare you to justify 3 things:

Man, I can't tell you how impressed I am with such adult discussion as
"I dare you".

>    1)  20 KHz power developement.

If you never consider anything new, you continue to build yesterday's
systems.

>    2)  Non Metric (english)  component selection with the
>    european modules being Metric.

Why should it be metric?  The bulk of the funding is from the United
States of America -- and we're not on the metric system.  Why not just
require everyone else to build non-metric to match the main station?

>    3)  Total failure to practice EVA until this year.

Fear of 'adult' critics like you who would flip out over the costs and
risks of 'unnecessary' EVA's.

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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

Date: Thu, 11 Mar 1993 20:48:24 GMT
From: Leigh Palmer <[e-mail]>
Subject: Bullets in Space
Newsgroups: sci.space

In article <[e-mail]> Brandon France,
[e-mail] writes:

>What would happen if an astronaut was in a geostationary orbit and fired
>a rifle directly toward the earth?  What path would the bullet take?
>Would the bullet actually hit the earth or would it assume some orbit?

The bullet would follow an elliptical path for any muzzle velocity less
than the orbital velocity (~3 km/s), and a hyperbolic path for any
velocity greater than this (Kepler, Newton).

If you assume a conventional hand-held rifle, then all muzzle velocities
are less than 3 km/s. Velocities much greater than this have been
achieved with stationary "rifles".

In the (rotating) frame of reference of the astronaut (oriented with his
body parallel to Earth's axis, his head pointing north, and facing Earth,
He will observe that his bullet veers to the right (which effect he may
ascribe to the Coriolis force acting in his frame). The gravitational
pull of Earth will act to oppose this deflection, but for any technically
accessible muzzle velocity this deflection will be sufficiently great
that the bullet will miss Earth by a very large amount.

If the bullet is retained in an elliptical orbit then the period of the
orbit will be greater than one day, since the energy per unit mass is
larger for the bullet (that is, it is less negative) after it has been
fired than before.

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

Date: Thu, 11 Mar 1993 23:11:29 GMT
From: Tom A Baker <[e-mail]>
Subject: Bullets in Space
Newsgroups: sci.space

In article <[e-mail]> Leigh Palmer <[e-mail]> writes:
>In article <[e-mail]> Brandon France,
>[e-mail] writes:
>
>>What would happen if an astronaut was in a geostationary orbit and fired
>>a rifle directly toward the earth?  What path would the bullet take?
>
>The bullet would follow an elliptical path for any muzzle velocity less
>than the orbital velocity (~3 km/s), and a hyperbolic path for any
>velocity greater than this (Kepler, Newton).
[deletion]
>If the bullet is retained in an elliptical orbit then the period of the
>orbit will be greater than one day, since the energy per unit mass is
>larger for the bullet (that is, it is less negative) after it has been
>fired than before.

Waitaminit.  I was taught that, if the delta vee was directly through the
center of the earth, then, elliptical orbit or not, the >impulse< would
not change the period of the orbit.  (Ignoring things like atmospheric
drag, etc.)  The bullet would still be geosynchronous.

tombaker

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

Date: 12 Mar 1993 01:15 UT
From: Ron Baalke <[e-mail]>
Subject: Galileo Update - 03/11/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Neal Ausman, Galileo Mission Director

                                    GALILEO
                        MISSION DIRECTOR STATUS REPORT
                                  POST-LAUNCH
                             March 5 - 11, 1993

SPACECRAFT
1.  On March 5, a Radio Frequency Subsystem Tracking Loop Capacitor (RFSTLC)
test was performed over DSS-63 (Madrid 70 meter antenna).  Preliminary
analysis indicates the capacitors continue to operate normally.

2.  On March 7, cruise science Memory Readouts (MROs) were performed for the
Magnetometer (MAG) instrument.  Preliminary analysis indicates the data was
received properly.

3.  On March 7, a Command Detector Unit Signal-to-Noise Ratio (CDUSNR) test
was performed using LGA-1 (Low Gain Antenna #1) over DSS-63.  Detailed
analysis of the data is in progress.

4.  On March 8, a Radio Frequency Subsystem Automatic Gain Control (RFSAGC)
test was performed using LGA-1 over DSS-43 (Canberra 70 meter antenna).
Quick look analysis indicates the test went well.  Detailed analysis is in
progress.

5.  On March 8, cruise science Memory Readouts (MROs) were performed for the
Extreme Ultraviolet Spectrometer (EUV).  The MROs were received without
incident.

6.  On March 8, the Trajectory Correction Maneuver (TCM-19) sequence memory
load was uplinked to the spacecraft without incident.  The Energetic Particle
Detector (EPD) instrument was stepped to Sector 0 which is the predicted least
contaminated position in preparation for the execution of TCM-19 and returned
to Sector 4 after completion of the maneuver.

7.  On March 8, real-time commands were sent to update the Acquisition Sensor
(AS) parameter for a solar distance of 1.5 AU.  The AS parameter is updated
periodically due to the changing spacecraft to sun distance.

8.  On March 9, TCM-19 was performed on the spacecraft.  The maneuver
consisted of two axial segments imparting a total delta velocity of 2.12 m/sec.
This maneuver was executed at 1200 bps with the spacecraft pointed
approximately three degrees off the sun.

     All RPM (Retro-Propulsion Module) pressures and temperatures and attitude
control indicators were near predicted levels.  After the axial burn segments,
the sequence planned spin correction executed but the pointing correction was
not needed.  Preliminary radio navigation data indicates a 0.25 percent
overburn.

9.  On March 10, Delayed Action Commands (DACs) were sent to perform a wobble
compensation prior to the scheduled spacecraft spinup to 10.5 RPM.  The DACs
to slew the Radioisotope Thermoelectric Generator (RTG) booms executed prior
to turning the RTG boom heaters off.

10. On March 10, real-time commands were sent to turn the RTG boom heaters off
and to update the attitude control subsystem parameters required to spin the
spacecraft up to 10.5 RPM.

11. On March 10, the 10 RPM spinup mini-sequence was uplinked to the
spacecraft without incident.  The spacecraft under stored sequence control
initiated the spinup at approximately 2047 UTC and completed at 2118 UTC for a
duration of 31 minutes.  After the spinup completed, real-time commands were
sent to lower the star scanner threshold in order to obtain star data for
attitude and wobble determination.

12. On March 10, while the spacecraft was at high spin (10.5 rpm), real-time
commands were sent to warmup the High Gain Antenna (HGA) motors and to hammer
the motors for 540 pulses at 1.25 hertz at a 33.3 percent duty cycle.
Subsequent analysis of motor current data indicated no change to the HGA
configuration.

13. From the period from March 9 to March 11, a navigation cycle was performed.
This navigation cycle provided near-continuous acquisition of two-way doppler
and ranging data during four consecutive passes of the spacecraft over DSS-14,
(Goldstone 70 meter antenna), DSS-42 (Canberra 34 meter antenna), DSS-63, and
then back to DSS-14.

14. The AC/DC bus imbalance measurements have not exhibited significant change
(greater than 25 DN) throughout this period.  The AC measurement reads 20 DN
(4.5 volts).  The DC measurement reads 140 DN (16.4 volts).  These
measurements are consistent with the model developed by the AC/DC special
anomaly team.

15. The Spacecraft status as of March 11, 1993, is as follows:

       a)  System Power Margin -  64 watts
       b)  Spin Configuration - All-Spin
       c)  Spin Rate/Sensor - 10.5rpm/Acquisition Sensor
       d)  Spacecraft Attitude is approximately 4 degrees
           off-sun (lagging) and 8 degrees off-earth (lagging)
       e)  Downlink telemetry rate/antenna- 1200bps(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, SSI, and DDS
       i)  Probe/RRH - powered off, temperatures within
           acceptable range
       j)  CMD Loss Timer Setting - 240 hours
           Time To Initiation - 219 hours


UPLINK GENERATION/COMMAND REVIEW AND APPROVAL:

1.  The Trajectory Correction Maneuver (TCM-19) sequence memory load was
approved for transmission by the Project on March 5, 1993.  TCM-19 is a one
portion maneuver scheduled to execute on March 9, 1993 consisting of two
axial segments.  The estimated total delta velocity for TCM-19 is 2.12 m/sec.

2.  The EJ-1 (Earth-Jupiter #1) preliminary sequence and command generation
package was approved by the Project on March 9, 1993.  This sequence covers
spacecraft activities from April 12, 1993 to June 14, 1993 and includes the
Radio Relay Antenna (RRA) slew test on April 28, 1993.


GDS (Ground Data Systems):

1.  A Galileo GCF (Ground Communication Facility) 1.5 Upgrade Flow Test (CMD)
was performed on March 11, 1993, from 15:00:00 to 17:00:00 GMT using CTA-21
(Compatibility Test Area 21) .  The purpose of this test was to perform a
command flow through the SFOC Gateway (SG) to the Error Correction and
Switching (ECS) instead of through the External User Gateway (EUG).  This
test exercised command only for Galileo.  The MCCC command system
successfully sent commands (directives) to the CPA (Command Processor
Assembly) with performance as expected.  The Galileo SCO participated
in this test and reported the flow through the 1.5 GCF upgrade performed
nominally.  A retest of the telemetry portion of the GCF 1.5 Upgrade testing
is still planned to take place prior to DSN's (Deep Space Network)
March 15 on-line date.

     A Galileo SCP (Station Commuication Processor) test was performed
March 9, 1993, from 08:00:00 to 12:00:00 GMT using CTA-21.  The purpose of
this test was to perform a command, telemetry, monitor and tracking flow
through the new version of SCP software that is supporting the GCF 1.5 upgrade.
This test exercised command, telemetry, monitor, and tracking for Galileo.
The test was successful in flowing all data through the new SCP.  Performance
was nominal and supported low and high rate telemetry.

     A MOSO System test for Galileo MGDS V18.0 Command was performed
March 9, 1993, from 20:00:00 to 01:00:00 GMT using DSS-65 (Madrid 34 meter
antenna).  The purpose of this test was to exercise the connectivity of
V18.0 CMD with an actual station (and CPA).  The test was successful and
commands and directives were sent to the CPA by MGDS CMD.  Approximately 75%
of the MOSO system test objectives were completed and passed; 25% of the test
objectives could not be tested at this time and are scheduled for inclusion
in V18.1.  The GLL SCO participated in the test and reported satisfactory
results (including performance).  The STR for V18 was held March 10, 1993
and was approved to be used for UAT/GDS testing.

TRAJECTORY

     As of noon Thursday, March 11, 1993, the Galileo Spacecraft trajectory
status was as follows:

    Distance from Earth         82,596,500 km (0.55 AU)
    Distance from Sun           229,680,800 km (1.54 AU)
    Heliocentric Speed          106,300 km per hour
    Distance from Jupiter       609,095,400 km
    Round Trip Light Time       9 minutes, 14 seconds


SPECIAL TOPIC

1.  As of March 11, 1993, a total of 67580 real-time commands have been
transmitted to Galileo since Launch.  Of these, 62474  were initiated in the
sequence design process and 5106 initiated in the real-time command process.
In the past week, 2481 real time commands were transmitted: 2481 were
initiated in the sequence design process and none initiated in the real time
command process.  Major command activities included commands to uplink the
TCM-19 sequence memory load, update acquisition sensor parameters, perform a
wobble compensation, turn the RTG boom heaters off, update AACS parameters,
uplink the 10 rpm spinup mini-sequence, and hammer the HGA motors.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | It's kind of fun to do
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/  |_|/       |_____|/                     | Walt Disney

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

Date: 11 Mar 93 18:31:32 GMT
From: Greg F Walz Chojnacki <[e-mail]>
Subject: Lawsonomy (was Re: ALTERNATIVE Comet Rendezvous Mission)
Newsgroups: talk.politics.space,sci.space

>
> You can read about this cult in Martin Gardner's classic *Fads and
> Fallacies in the Name of Science*.  Also, there is a recent biography
> of Lawson that looks good, but I haven't read it;   I think it may be
> called *Zig-Zag and Swirl*.  People who drive Interstate 94 between
> Chicago and Milwaukee will notice the University of Lawsonomy sign
> somewhere in Wisconsin.
>

As someone who has often made that drive, I can add that, besides his peculiar
ideas, Lawson is also credited with designing the first commercial airliner.
(There's probably an interesting connection betwen that fact and sci.space,
but I'm unwilling to explore it.)

Greg

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

Date: 11 Mar 93 16:32:44 GMT
From: John Papp <[e-mail]>
Subject: Lunar Ice Transport
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Ross  Borden ([e-mail]) wrote:
>:     In all the Lunar ice transportation proposals that I've seen,
>: nobody has mentioned what would be, on Earth, the most obvious: overland
>: hauling.
>:     To maintain high through-put, a continuous stream of vehicles
>: would haul ice from the polar ice mines to the equatorial processing
>: plants, and then dead-head back (unless there was some return cargo.)
>
>The extremely tenuous Lunar atmosphere offers another "overland hauling"
>possibility: ballistic delivery.  Put a fast conveyor belt at one end,
>and a large bucket at the other:
>
>
From a student who is doing this next to impossible project, we are
currently designing a rail gun to deliver the ice with a hopper at
the end to catch it for much the same reasons you gave.  Unfortunately,
there are other considerations.  What happens to the ice when it
accelerates.  Does it melt, stay solid, explode?  For now, I'm assuming
it stays solid.  Controlability could also be a problem.
--
-------------------------------------------------------------
|                  |                            |
| John L. Papp        | "You sound like a manure salesman   |
| [e-mail]  |  with a mouth full of samples."     |

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

Date: Thu, 11 Mar 1993 22:40:07 GMT
From: [e-mail]
Subject: Moons rotation period question
Newsgroups: sci.space

In article <[e-mail]>,
[e-mail] (fred j mccall 575-3539) wrote:
> We used to think that Mercury was tidally
> locked to the Sun, but it turns out that it is not.

Ah, but it is!  While not in the simple 1:1 synchronous rotation once
immortalized in every other 50's era work of cheep SF, Mercury is
indeed spin-orbit coupled with the Sun.  The coupling is in a ratio
of 3:2.  It makes for, among other things, a Hermian 'day' that is
two Hermian 'years' long.

-Bill Gawne,  Space Telescope Science Institute

 "Forgive him, he is a barbarian, who thinks the customs of his tribe
  are the laws of the universe."                       - G. J. Caesar

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

Date: 10 Mar 93  11:28:38
From: [e-mail]
Subject: More on LRDPA
Newsgroups: sci.space

            Return to the Moon Campaign Makes Progress

        With the release of the second draft of the Lunar Resources
Data Purchase Act, a major milestone in the effort to move
America back to exploration of the Moon has been reached. The
first draft, released on January 28 of this year, was reviewed
favorably by many individuals and organizations, and was revised
in accordance with constructive suggestions. The new version is
likely to be more acceptable to members of Congress interested
in enacting the bill into law. The next step in the campaign is
for the bill to be introduced in Congress.
        The movement to pass the Lunar Resources Data Purchase Act
is called the Return to the Moon campaign. There are several other
organizations,  conducting similar, parallel efforts to redirect
the space program back to lunar exploration; the LRDPA is a
short term approach to lunar exploration that would authorize
the Federal government to purchase lunar science data from
private vendors, selected on the basis of competitive bidding.
The data would be acquired from inexpensive probes in lunar
polar orbits. One analyst has said about the LRDPA:  "This
important initiative may be like the rudder of a giant ocean
going ship. By turning the little flat piece of metal, an
incredibly massive vehicle slowly begins to change direction".
The authors of the LRDPA hope that all other pro-lunar groups
will support this new approach as part of their strategy in
promoting a return to the Moon.
        San Diego L5 and OASIS, two southern California chapters
of the National Space Society, support the Lunar Resources Data
Purchase Act, and hope that all readers of this join in the
Return to the Moon campaign by letting their elected officials
know (in writing) that their constituents want them to assist
in the introduction of the LRPDA.
        For more information, please call OASIS at 310/364-2290,
or San Diego L5 at 619/295-3690.
        A Return to the Moon briefing book, which contains
information about lunar exploration, and a draft copy of the bill,
is now available for people wishing to participate in enacting this
important legislation. Please E-mail a U.S. postal service address
for the briefing book, or a fax number for a copy of the bill.

--- Maximus 2.01wb

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

Date: 11 Mar 93 18:58:43 GMT
From: Gary Hughes - VMS Development <[e-mail]>
Subject: Rocket Propulsion
Newsgroups: sci.space

Someone has already pointed out that rocket propulsion goes back a long way
before Goddard (remember "the rockets' red glare"?)

However he was certainly a pioneer of liquid propellant rocketry. Some time
after his death, NASA paid his widow $1million for the patents he held.

I beleive the VfR (German pre-WWII rocket society) tried to contact Goddard,
but after the lampooning he got in the press after publishing "A method for
reaching extreme altitudes" he was reluctant to pass on much information.

The Smithsonian Annals of Flight series had a very good book on early rocketry,
covering developments in the early part of this century in various countries. I
can dig up the ISBN etc if requested.

You might try reading Goddard's original paper that I mentioned above. It makes
for an interesting afternoon's reading.

gary

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

Date: 12 Mar 1993 02:00 UT
From: Ron Baalke <[e-mail]>
Subject: SR-71 Maiden Science Flight
Newsgroups: sci.space

Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. [phone]

Contact: Mary A. Hardin

FOR IMMEDIATE RELEASE                             March 11, 1993
#1498

     The first science flight of a high-speed ex-reconnaissance
aircraft took place March 9 from California's Edwards Air Force
Base, carrying a payload operated by scientists at the Jet
Propulsion Laboratory.

     The second scientific test flight of the SR-71 Blackbird,
carrying an ultraviolet camera which studies stars and comets,
will take place on Friday, March 12.

     "This is really a case of turning swords into plough
shares," said Dr. Jacklyn R. Green, the JPL SR-71 project
scientist.  "We are taking what was once a spy plane and
transforming it into a useful, cost-effective science platform."

     During the one and a half hour flight, the SR-71 climbed to
an altitude of 85,000 feet with an upward-looking ultraviolet
camera system mounted in its nose bay.  "We are doing astronomy
at mach 3 (2,100 mph) and no one else has ever done that before,"
Green said.

      The faster the plane goes the higher it soars and it is the
high altitude that makes the Blackbird such an important
scientific asset.  Flying above a significant portion of the
Earth's atmosphere, scientists can observe stars and planets at
ultraviolet wavelengths that are blocked to ground-based
astronomers.  Using the high altitude SR-71 as a scientific
platform enables scientists to do ultraviolet astronomy more
cost-effectively and it opens the door to a wide range of other
scientific applications, such as the study of comets, asteroids
and astrophysics.

     The maiden flight of the SR-71 as a scientific platform had
two key objectives:  to determine how the camera responds under
different lighting conditions such as daylight, twilight and
nighttime and to test the camera's resolution in relation to the
effects of vibration and turbulence.

     "We want to determine how faint an object we can observe,"
Green said. "The results of the first flight look good.  We were
able to see Mars and the constellation Orion, among other stars.
The ride appeared to be totally smooth and we couldn't detect any
vibration in the images."

     Subsequent flights will add other instruments such as
ultraviolet spectrometers and infrared and ultraviolet sensors.

     Green is working with universities, industry and other
government agencies to ensure the SR-71 is accessible to multiple
scientific disciplines.  "This is a cooperative effort.  We want
to evaluate and develop this plane to make it a national
resource.  We want to be a flying observatory," Green added.

     The ultraviolet camera system was provided by the Southwest
Research Institute of San Antonio, Texas.

     The aircraft is operated by NASA's Dryden Flight Research
Facility.

     The SR-71 scientific testbed research is funded by the
Aeronautics Technology Division at NASA Headquarters.

                              #####

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | It's kind of fun to do
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/  |_|/       |_____|/                     | Walt Disney

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

Date: 11 Mar 93 19:17:33 GMT
From: Anthony E Bible <[e-mail]>
Subject: Winding trails from rocket
Newsgroups: sci.astro,sci.space,sci.geo.meteorology

In article <[e-mail]> [e-mail] (boyd johnson) writes:
>
>Is it the wind currents that twists the contrail or does the rocket
>follow a looping, circling route?  Also, it is always the same time of
>day.  Is this the only time the contrails are visible from a distance,
>or is it when the best atmospheric conditions exist for launch?
>I am about 250 miles from VAFB, so I assume it is visible from
>beyond the Mexican border to San Francisco or so.
>

    I can respond to the question about time of day.  Launches from
Vandenberg go into (nearly) polar orbits.  The time of day determines what the
angle will be between the orbital plane and the sun.  For example, launch at
sunset or sunrise and you get a twilight orbit which has a 90 degree sun angle.
Launch into a noon orbit (high noon or midnight) and you have a zero degree sun
angle.  One of the reasons this is important is the sun angle determines the
heat loads and distribution on the vehicle.  A twilight orbit puts one side
always to the sun and the other always to outer space.  In that case you'd like
to paint the vehicle so it absorbs little solar on one side and radiates little
heat on the other.  Of course, after three months all twilight orbits become
noon orbits and vice versa, but for short flights it's a factor.  A long time
ago that's why vehicles were painted that checkerboard black and white pattern.
It was to get the correct ratio of solar absorptivity and infra-red emissivity
for the orbit.  I don't know if they still do that or not.
    Sorry to ramble on so about something not meteorological, but it's one
of the few things I know about -- a bit.


Regards,
Tony

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

Date: Thu, 11 Mar 1993 19:40:24 GMT
From: [e-mail]
Subject: Winding trails from rocket
Newsgroups: sci.astro,sci.space,sci.geo.meteorology

In article <[e-mail]>, [e-mail] (boyd johnson) writes:

 > I'm sure many of you in Southern California saw the rocket contrail from
 > Vandenberg Air Force Base last night (Tuesday) at sunset.  I have never
 > seen one as it is created, but have seen it many times some time after
 > it happens.
 >
 > It always seems to resemble something like what you'd get if you took
 > the northern lights (aurora borealis) stretched them out, then let it
 > snap into a tangled mess.  The trail is nearly vertical near the earth,
 > but as it ascends it appears to go out of control.
 >
 > Is it the wind currents that twists the contrail or does the rocket
 > follow a looping, circling route?

I don't know the particulars here, but many years ago (as an undergraduate in
fact) I worked for a "Project Firefly" in which sounding rockets with luminous
trails were launched from Wallops Island and also from Barbados to explore the
upper atmosphere.  The trails would quickly develop spectacular kinks at an
altitude of around 100 km as I recall, due to strong shear winds at that
altitude.

 > Also, it is always the same time of
 > day.  Is this the only time the contrails are visible from a distance,
 > or is it when the best atmospheric conditions exist for launch?

We used to launch in evening twilight, when the ground was dark but the trails
at high altitudes would be in sunlight.

Ben

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

Date: Thu, 11 Mar 1993 21:29:49 GMT
From: Joe Cain <[e-mail]>
Subject: Winding trails from rocket
Newsgroups: sci.astro,sci.space,sci.geo.meteorology

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] (boyd johnson) writes:
>
> > I'm sure many of you in Southern California saw the rocket contrail from
> > Vandenberg Air Force Base last night (Tuesday) at sunset.  I have never
> > seen one as it is created, but have seen it many times some time after
> > it happens.
> >
> > It always seems to resemble something like what you'd get if you took
> > the northern lights (aurora borealis) stretched them out, then let it
> > snap into a tangled mess.  The trail is nearly vertical near the earth,
> > but as it ascends it appears to go out of control.

the direction of glow streamers from gases due to the aurora should be
oriented along the ambient magnetic field. i.e. the energizing
particles should be painting the field lines. Thus there should be no
"kinks"

> > ...
>..... many years ago (as an undergraduate in
>fact) I worked for a "Project Firefly" in which sounding rockets with luminous
>trails were launched from Wallops Island and also from Barbados to explore the
>upper atmosphere.  The trails would quickly develop spectacular kinks at an
>altitude of around 100 km as I recall, due to strong shear winds at that
>altitude.
>
> > ....Also, it is always the same time of
> > day.  Is this the only time the contrails are visible from a distance,
> > or is it when the best atmospheric conditions exist for launch?
>
>We used to launch in evening twilight, when the ground was dark but the trails
>at high altitudes would be in sunlight.

Some of the luminous trails launched from Wallops were barium releases
so the material ionized by solar uv would respond to the electric
fields in the presence of the geomagnetic field. I am thus wondering
whether the observations reported herein indicated that indeed there
was a strong electric field at the 100 km altitude (where the
horizontal electrical conductivity peaks) assuming the "luminous
trails" indeed represented glow from ionized atoms or radicals.
Alternately, were the trails responding to a neutral wind?

Any clarification of these experiments might be interesting.


Joseph Cain        [e-mail]
[e-mail]        scri::cain
[phone]        FAX [phone] or -0098

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End of Space Digest Volume 16 : Issue 304
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