Date: Fri, 12 Mar 93 05:29:13 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu 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) Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " 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: 11 Mar 93 17:10:08 GMT From: fred j mccall 575-3539 Subject: 20 kHz Power Supplies "blowing up"! Newsgroups: sci.space Article-I.D.: mksol.1993Mar11.171008.1926 References: <1993Feb24.215924.16372@iti.org> <1n4441INN47i@access.digex.com> <1ng5a0INN1lp@access.digex.com> <9MAR199308521171@tm0006.lerc.nasa.gov> <1niun0INNi6t@access.digex.com> Organization: Texas Instruments Inc Lines: 147 Sender: news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU In <1niun0INNi6t@access.digex.com> prb@access.digex.com (Pat) writes: >In article <9MAR199308521171@tm0006.lerc.nasa.gov> dbm0000@tm0006.lerc.nasa.gov (David B. Mckissock) writes: >>In article <1ng5a0INN1lp@access.digex.com>, prb@access.digex.com (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 ------------------------------------------------------------------------------ Fred.McCall@dseg.ti.com - 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 Subject: Bullets in Space Newsgroups: sci.space In article <1993Feb27.192838.1@acad3.alaska.edu> Brandon France, fsbgf@acad3.alaska.edu 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 Subject: Bullets in Space Newsgroups: sci.space In article <1993Mar11.204824.15360@sfu.ca> Leigh Palmer writes: >In article <1993Feb27.192838.1@acad3.alaska.edu> Brandon France, >fsbgf@acad3.alaska.edu 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 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 | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | 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 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 Subject: Lunar Ice Transport Newsgroups: sci.space In article <1993Mar11.010842.26395@aio.jsc.nasa.gov> kjenks@gothamcity.jsc.nasa.gov writes: >Ross Borden (rborden@uglx.UVic.CA) 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 | | jpapp@uceng.uc.edu | with a mouth full of samples." | ------------------------------ Date: Thu, 11 Mar 1993 22:40:07 GMT From: gawne@stsci.edu Subject: Moons rotation period question Newsgroups: sci.space In article <1993Mar11.160821.29701@mksol.dseg.ti.com>, mccall@mksol.dseg.ti.com (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: David.Anderman@ofa123.fidonet.org 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 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 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. (818) 354-5011 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 | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | 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 Subject: Winding trails from rocket Newsgroups: sci.astro,sci.space,sci.geo.meteorology In article <1993Mar10.225944.1010@spectra.com> johnson@spectra.com (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: zellner@stsci.edu Subject: Winding trails from rocket Newsgroups: sci.astro,sci.space,sci.geo.meteorology In article <1993Mar10.225944.1010@spectra.com>, johnson@spectra.com (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 Subject: Winding trails from rocket Newsgroups: sci.astro,sci.space,sci.geo.meteorology In article <1993Mar11.144024.1@stsci.edu> zellner@stsci.edu writes: >In article <1993Mar10.225944.1010@spectra.com>, johnson@spectra.com (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 cain@geomag.gly.fsu.edu cain@fsu.bitnet scri::cain (904) 644-4014 FAX (904) 644-4214 or -0098 ------------------------------ End of Space Digest Volume 16 : Issue 304 ------------------------------