Date: Tue, 15 Dec 92 05:13:59 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #548 To: Space Digest Readers Precedence: bulk Space Digest Tue, 15 Dec 92 Volume 15 : Issue 548 Today's Topics: Mach 8+ Space/Spy Plane? Micro-g in KC-135 No asteroid flybys (was Re: Cassini Undergoes Intense Design Review) private space ventures 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: Tue, 15 Dec 1992 01:28:55 GMT From: "Richard A. Schumacher" Subject: Mach 8+ Space/Spy Plane? Newsgroups: sci.aeronautics,sci.space >>sonic booms but I't couldn't have been a jet airliner it was moving too fast >>I did notice it's contrail was lumpy like -+-+-+-+-+-+ like a pulse. >[no boom because] >be in an acoustical shadow zone. the same phenomenon exists in the ocean. of >course, maybe you really didn't see anything at all :) -ken But that pulsed contrail has been described before, in Av Week. Sounds to me like he saw the genuine article. ------------------------------ Date: 14 Dec 92 17:36:35 GMT From: kjenks@gothamcity.jsc.nasa.gov Subject: Micro-g in KC-135 Newsgroups: sci.space Keywords: microgravity Originator: kjenks@gothamcity Lines: 71 Source-Info: Sender is really news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU 1st: >In article <1gfti1INNaqj@rave.larc.nasa.gov> claudio@nmsb.larc.nasa.gov (Claudio Egalon) writes: >>What causes the microgravity in the KC-135 [...] ? 2nd: In article henry@zoo.toronto.edu (Henry Spencer) replied: >You don't "cancel" the gravitational acceleration, you fall with it. The >KC-135 flies the exact trajectory that it would follow if it were falling >free in a vacuum. > >That trajectory isn't exactly a parabola; it is in fact a segment of an >elliptical orbit (one that intersects the Earth's surface). It's very >close to being a parabola. It would *be* a parabola if the Earth were >flat and gravity did not diminish with altitude. 3rd: Henry's correct. Our KC-135 "Zero Gravity Trainer" follows a trajectory which causes all of the objects inside the aircraft to fall at the same speed as the aircraft itself. Since there is some air resistance, the pilot does apply some power, and he keeps an eye on the G-meter in the cockpit. The KC-135 flight starts off at Ellington Field a few miles north of JSC. The experimenters (and the experimental test subjects) stay in their seats at the rear of the plane until the plane gets out over the Gulf of Mexico, at which time the people get up and set up their experiments. The airplane flies about 40 parabolas, with about 2 minutes of 1.8 G, then 30 seconds of (nearly) zero G, then 2 minutes of 1.8 G, etc. There are longer gaps (at 1 G) between some of the parabolas as the pilot navigates and/or steers around weather. What surprised me about the KC-135 was that the gravity was so variable. It was nowhere near MICROgravity; it was closer to 0 G +/- 0.1 G. During the periods of low gravity, everything in the padded cargo/experiment area floats about and drifts around as the accelleration vectors shift due to bumpy air, wind gusts, etc. There is very little variation in accelleration along the plane's X-axis (tail to nose) and Y-axis (left/right), but there are variations in the Z-axis (up/down). If you are strapped down with an experiment in your lap (as I was), your experiment will float "up" and "down." However, if you and your experiment are both floating, you'll stay together. At the end of the set of parabolas, the aircraft makes a broad swing around and flies back to Ellington. During this time, those experimenters who are still able to function stow their equipment and make their way back to the seats where the rest of us are recovering. On the flights I was on, there was quite a variety of experiments, including an improved treadmill, an excercize bike, a test of a foot restraint system, a fluid dynamics experiment, some tests of the Space Station food service equipment (paper plates don't cut it), and my Portable Aerodynamic Work Surface (PAWS) experiment. On my third flight, there were some new astronauts undergoing zero-G familiarization training. On my first two flights, I barfed. Quite a lot on the first flight, and only once (on the downside of parabola 35) on the second flight. I had no trouble on the third flight, and we went to Pe-Te's Barbeque for Cajun food after we landed. I was doped to the gills on Scop-Dex, a mixture of scopalamine and dexadrine. GIF available upon request. (Blech.) -- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office kjenks@gothamcity.jsc.nasa.gov (713) 483-4368 "We choose to go to the moon not because it is easy, but because it is fun." -- John F. Kennedy, as [mis]quoted by Scott Brigham, scotbri@rosemount.com, in alt.folklore.urban ------------------------------ Date: Tue, 15 Dec 1992 01:09:43 GMT From: "Richard A. Schumacher" Subject: No asteroid flybys (was Re: Cassini Undergoes Intense Design Review) Newsgroups: sci.space,sci.astro,alt.sci.planetary >Nope. It was announced in *Aviation Leak* that the policy of seeking >asteroid flybys has been dropped to keep costs down on Cassini. :-( Swell. WIth our luck the damn thing will probably wind up colliding with an asteroid, which collision would have been recognized had we but continued the search for flyby possibilities... ------------------------------ Date: 15 Dec 92 00:26:25 GMT From: Todd Deckard 4-6606 MRCE Subject: private space ventures Newsgroups: sci.space,sci.aeronautics I am looking for information on firms working to provide privately originated launch services. Please respond via email. Thanks in advance! Todd ------------------------------ End of Space Digest Volume 15 : Issue 548 ------------------------------