Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from corsica.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests) ID ; Mon, 4 Sep 89 03:17:38 -0400 (EDT) Message-ID: <8Z0W68i00UkVQONE5z@andrew.cmu.edu> Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 4 Sep 89 03:17:29 -0400 (EDT) Subject: SPACE Digest V10 #18 SPACE Digest Volume 10 : Issue 18 Today's Topics: MONITORING VOYAGER solar orbiting probes SCI.AERONAUTICS has been created... Re: Where the hell are electric-ion thrusters???? Printing On a LaserWriter -- hints Neptune: Wrong format Re: Voyager Interstellar Trajectory Re: PHONE TREE ALERT Re: voyager audio ---------------------------------------------------------------------- Date: 28 Aug 89 09:01:41 GMT From: mcsun!ukc!tcdcs!csvax1.cs.tcd.ie!vax1.tcd.ie!dflynch@uunet.uu.net Subject: MONITORING VOYAGER In article <17463@bellcore.bellcore.com>, karn@ka9q.bellcore.com (Phil Karn) writes: > Here's another link calculation for Voyager 2 at Neptune. I got some more > precise figures, and the result looks pretty reasonable. My references to > "Yuen" are to the book "Deep Space Telecommunications Systems Engineering", > edited by Joseph H. Yuen and published by Plenum (ISBN 0-306-41489-9). > > 8415 MHz transmitter power +11.04 dBW > (12.7 W - low power mode ref Yuen): > 3.7 m spacecraft antenna gain > (ref Yuen p 4): +48.13 dB > EIRP: +59.17 dBW > > Path loss, 4.416e9 km, 8415 MHz: 303.85 dB > = 20 log10(4*pi*d*f/c) > > Receive signal flux: -244.68 dBW > > 70m receive antenna gain: +73.8 dB > = 10 log(4*pi*A/lambda^2) - N > lambda = C/8415e6 = 3.56cm > (assuming N = 2 dB illum loss) > > Receive signal power: -170.88 dBW = 8.16e-18 W > = 8.16 attowatts > = 8.16 nano nano watts > > Received energy per bit (Eb): -214.22 dBJ = 3.78e-22 J > at 21.6 kb/s (43.34 dB-b/s) = .000378 attojoules > = 0.378 piconanojoules > > Receive noise density (N0): -218.60 dBW-Hz > = 10 log10(kT) > T = 10 Kelvin (ref USENET) > > Eb/N0 ratio: 4.38 dB > > This is quite consistent with the performance of the concatenated rate 1/2 > Reed Solomon + rate 1/2 convolutional coder, which according to Yuen (p 255) > has a very steep "wall" or threshold just below 3 dB. > > However, this figure does not take into account miscellaneous losses > (connectors, feedlines, etc) on board Voyager or at the receiving site, nor > does it allow for atmospheric absorption or transmitter degradation below > the nominal 12.7 watt figure. > > According to an interview carried tonight on NASA select, the arraying of > the VLA to Goldstone effectively doubles the aperture of the receiver, so > this should give another 3 dB of margin to compensate for these factors. > > As you can see, attention to detail is all-important here! > > Phil JPL AMATEUR RADIO NETWORK LINKED TO VOYAGER PROJECT ACTIVE UNTIL SEPTEMBER 9. TIMES UNCERTAIN, BUT 21335 AND 14235 KHZ USB USED. ALSO 3.8* MHZ OUTLET. I HAVE HEARD NO NASA TRAFFIC ON 20192 / 20198, FREQUENT NASA CHANNELS HEARD HERE. ANY MORE DETAILS BEFORE IT IS TOO LATE ? POST TO NEWSGROUP ------------------------------ Date: 29 Aug 89 18:49:22 GMT From: mailrus!jarvis.csri.toronto.edu!utgpu!watmath!watcgl!electro!ignac@tut.cis.ohio-state.edu (Ignac Kolenko) Subject: solar orbiting probes just wondering: i remember back in the early 60's some of the initial attempts at putting something (or should i say, crashing something) on the moon failed, and the probes ended up in solar orbit. has anyone launched a probe that purposely ended up in solar orbit to study the sun?? would there be any benefit to doing so rather than keeping the probe in orbit around the earth (ie: solar max mission)?? by the way, what's the oldest probe/satellite that we still have contact with?? anything from the 60's still communicating?? and now we return you to reality ... -- =====Ignac A. Kolenko (The Ig) watmath!watcgl!electro!ignac===== co-author of QuickST, and the entire line of Quick Shareware!!!! "I don't care if I don't win, 'cause I don't care if I fail" from 'Youth Of Today' by SUBURBAN DISTORTION ------------------------------ Date: 29 Aug 89 20:54:40 GMT From: cs.utexas.edu!ut-emx!walt.cc.utexas.edu!mentat@tut.cis.ohio-state.edu (Robert Dorsett) Subject: SCI.AERONAUTICS has been created... SCI.AERONAUTICS has been created. The group is dedicated to discussions con- cerning human factors, airline operations, avionics, systems, aerodynamics, and control issues--in essence, the topics which, for various reasons, never seem to do well on rec.aviation, or which get buried in the FAR-flood. :-) The newsgroup is not intended to replace rec.aviation. A mailing list, in support of interested persons without access to usenet, has also been established. It will be a moderated (by me) version of sci.aeronautics postings. Pertinent addresses are: Administravia, requests (to get on or off the list), etc: aeronautics-request@rascal.ics.utexas.edu Posts: aeronautics@rascal.ics.utexas.edu Robert Dorsett Internet: mentat@walt.cc.utexas.edu UUCP: ...cs.utexas.edu!walt.cc.utexas.edu!mentat ------------------------------ Date: 29 Aug 89 15:32:47 GMT From: jarvis.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Where the hell are electric-ion thrusters???? In article <6091@lynx.UUCP> neal@lynx.UUCP (Neal Woodall) writes: >... Why the hell cannot our country do with two fewer >B2 bombers, and give that money to JPL for probes, including a full >program of electric-ion engine probes to various parts of the solar system? Because Congress isn't willing to move funds around like that. If you feel this is unfair... have you talked to *YOUR* Congressthing about it lately? If not, why not? >... Hell, a manned Mars mission would be fast with an ion thruster! Well, let's not get carried away; the thrust of the things is pretty low. But yes, it would help. Which is why the Soviets are working on nuclear- electric propulsion for their Mars mission. -- V7 /bin/mail source: 554 lines.| Henry Spencer at U of Toronto Zoology 1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 29 Aug 89 18:26:55 GMT From: lorelei!lemay@sun.com (Laura Lemay) Subject: Printing On a LaserWriter -- hints A bunch of people seem to be asking stuff about printing to the laserwriter, so here's a big posting to cover all the questions: 1. When I made up transparencies on my mac, they looked fine. When I brought them into the mac shop to be printed on the LW, they came out all wrong. Whats going on here? Although the Mac advertises as WYSIWYG, it is not necessarily so. Fonts that are displayed on the screen are not the same size/shape etc as the postscript fonts that appear printed on the LW. So the laserwriter reformats everything as best it can with the font it is told to use. (All right, LW hackers, thats not a scientific explanation, but it'll do.) The easy solution I've discovered for this is to pop a laserwriter driver into your system folder. If you are pressed for space, you don't need the laser prep, just the driver. Then, before you start working with any formatting, select the chooser from the apple menu (oh, you also need to install this DA if you don`t have it.) It'll ask you a whole bunch of stuff about appletalk and the laserwriter. NOTE: you do NOT need appletalk or a laserwriter or even a printer at all to do this. The goal is to make the mac THINK that its printing to a laserwriter. Then, the mac will try to use laserwriter spacing, etc and things should come out properly. 2. I've noticed the laserwriter doesn't print along the outer 1/4" of the page. Is there any way to change that? Nope. Sorry. Since the LW is such a small printer, it needs that space around the edges of the paper to pull the paper through. Its very irking, but its a fact of life. 3. How do I keep a startup page from printing when I turn on the laserwriter? This has been beaten to death on this bboard for a while now, but basically tehre are two ways to do it: 1. (If you're not a postscript hacker). Pull out the paper tray an inch or so when the LW starts up, until the orange light goes on steadily. 2. (If you are a postscript hacker). Damn. I thought I rememebred this one. Basically it involves getting into interactive mode with the laserwriter (or sending a script to the LW interactively), and changing a variable called "setdostartpage." Sigh. Is tehre someone out there who could write the actual script to be downloaded to the LW and post it? 3. I just did a paper using the "london" font, which I really like. But when I printed it on the LW, it said "Font London not found, using bitmap." London is right there on my system, why can't it find it? This was the most commonly asked question when I was managing a macintosh center in college. So here's my treatise on the subject: There are two types of fonts: screen fonts and printer fonts. The screen fonts are the ones you (obviously) see on your screen, and also the ones you install in your system file using font/da mover. These are called bitmap fonts, becasue they are made up of single dots (bits) on your screen. When you print on an imagewriter (this may have changed, I don't know how the new imagewriters work), these bits are downloaded directly to the paper. If a dot is black on the screen, it is printed on the page. So you can always print any font you want on an imagewriter. However, the laserwriter is infinitely different. The laserwriter contains a whole differetn set of fonts, called postscript outline fonts. These are mathematical descriptions on fonts, rather than bits. What fonts exist in your laserwriter depends on the particular laserwriter. None of them will have London. What your macintosh application does when it prints is send the NAME of the fonts down to the printer, and the printer calls up that piece of code for the font to print everything. If there isn't a match between the name the app sends it and the list of internal fonts, the LW will do one of two things -- it will substitute another font it knows (courier for monaco, times for new york, etc), or it will bitmap the screen font onto the page. When the laserwriter makes bitmaps, they will usually come out looking ragged and strange. This is because of the differences in resolution between the screen and the page. On the screen, there are 72 dots per inch (dpi). The laserwriter prints at 300 dpi. Some other printers can print at even higher resolutions (400, 1200, etc.). In any case, the size of a dot on the screen is a lot bigger than the size of a dot on the page. This is why fonts look ragged on the printer. There is a "font smoothing" option in many applications; sometimes this makes the fonts look better when printed, but often doesn't work very well at all. Your best bet is to stick to fonts that the laserwriter has in memory. On interesting quirk of having fonts in the laserwriter is that these mathematical formulas for fonts can be scaled to any size. You may only have four sizes of a particular font installed in you system, but you can print any size you want on the LW. Depending on the program you use, larger or wierd size fonts will either not be available or will come out looking really wierd on the screen. But they will look fine when printed. whew. Hope this has helped..... -Laura Lemay lemay%lorelei@sun.com Redhead. Drummer. Geek. ------------------------------ Date: 29 Aug 89 02:10:00 GMT From: ux1.cso.uiuc.edu!uxa.cso.uiuc.edu!sfn20715@uxc.cso.uiuc.edu Subject: Neptune: Wrong format I just got the Voyager pics from an FTP source; unfortunately I have no Mac II. This is a request for the same pics in "your favorite format". Has anyone out there converted them yet? My favorite format is GIF, but I might be able to deal with many other formats if GIF is not available. If you have done any conversions, please email me and tell me. Thanks in advance. sfn20715@uxa.cso.uiuc.edu ------------------------------ Date: 29 Aug 89 13:30:35 GMT From: netnews.upenn.edu!eniac.seas.upenn.edu!barron@rutgers.edu (Daniel P. Barron) Subject: Re: Voyager Interstellar Trajectory In article <62446@philabs.Philips.Com> rfc@briar.philips.com.UUCP (Robert Casey) writes: >In article <4255@utastro.UUCP> terry@astro.UUCP (Terry Hancock) writes: >>>The answer was that in 8,000 years it will fly by Barnard's Star, in 20,000 or >>>so it will pass Proxima Centauri, and then the Oort cloud. >I saw in the Planetary Report a diagram of sorts that described some >"approaches" of some stars by Voyager 2. It was something like "When Voyager >2 is 1/4 ly from the Sun, it makes its closest approach to (some star) and it >comes as "close" as 4 lys. Not exactly a near miss! Am I completely crazy or do I remember someone on "Neptune All Night" saying that Voyager two will (eventually) pass within a light year of Sirius? Again, not exactly a near miss, but I was wondering if anyone else heard this. While somewhat interesting, Neptune All Night did have a large amount of specious commentary, so this factlet could be wrong. Did anyone else watch the show? It originated at the studios of (TA DA!) my very own PBS station, WHYY in Philadelphia. They showed "real time" images coming in from Neptune on the night of closest approach. Most of the images were only 6 minutes old! (i.e. received 6 minutes ago, sent 4 hours, 12 minutes ago) Of course, WHYY took the oppurtunity to interrupt every 20 minutes to tell you that "you can become part of history by calling 1-800-228-1234 and pledging your support to channel 12!" db ________________________________Daniel Barron__________________________________ ______________________________________ ________________________________________ "There are four types of homicide: | E-mail: barron@eniac.seas.upenn.edu felonious, excusable, justifiable | barron@wharton.upenn.edu and praiseworthy." --Ambrose Bierce | barron@dacth01.bitnet ______________________________________|________________________________________ ------------------------------ Date: 28 Aug 89 23:32:43 GMT From: att!mtuxo!mtgzx!dls@ucbvax.Berkeley.EDU (d.l.skran) Subject: Re: PHONE TREE ALERT In article <14597@bfmny0.UUCP>, tneff@bfmny0.UUCP (Tom Neff) writes: > > > First of all, > > and second of all, what does it imply about the collective IQ of NSS members > to suggest that they can't tell the difference themselves at this point? Although I am sure that that many net readers can immdiately spot the difference between Baxter's fake "PHONE TREE ALERTS" and the real thing, I am writing for the benefit of innocent new NSS members who have yet to discover the complexities of pro-space activism, and who probably think Baxter holds some high office at NSS Headquarters. I ask Mr. Baxter, in the spirit of truthfulness, to refer to his personal alerts as BAXTER ALERTS or BAXTER SPACE ACTIVIST ALERTS or somesuch. > > Baxter's postings reflect concrete advocacy. Skran's are irrelevant > intramural politics. It is true that this particular posting by Baxter does represent concrete advocacy. However, this is not typical of Mr. Baxter's contributions to the net, which consist mainly of unconstructive personal attacks on Mark Hopkins, and diatribes against NASA management and NSS leadership. I would further like to state that I personally support this bill, and that as far as I know so do Scot Pace and the NSS Legislative Committee. The bill has been distributed by NSS Headquarters to chapters so they can organize support for it. In fact, I know of no one who actually opposes this bill. Dale Skran ------------------------------ Date: 29 Aug 89 13:59:52 GMT From: adam@MEDIA-LAB.MEDIA.MIT.EDU (Adam Glass) Subject: Re: voyager audio jay@ncspm.ncsu.edu (Jay C. Smith) writes: > adam@mit-amt.MEDIA.MIT.EDU (I) write: > >That's funny; it was on a Boston radio station the other day (yes, the > >WHOLE LP). I think the station was WMBR, but I'm not sure... I'll > >try to get in contact with them, I suppose... > > The local public radio station here (WUNC) played the same thing last week, > but during a break half-way through it the announcer mentioned that the > recording was not commercially available. He should have mentioned that > before he began playing it. I didn't hear all of it; I missed the beginning. Perhaps the radio station would allow you to copy it? I mean, what is the big deal? NASA doesn't want a commercial record company to make money off of the disc. But as long as it's non-commercial and you don't go selling copies once you yourself get a copy, I should think that it would be all right... no? Adam -- "He didn't fall? Inconceivable!" Internet email: adam@media-lab.media.mit.edu "You keep using that word... I do not think it means what you think it means." (All stolen quotes taken from The Princess Bride) Hmm... 18 spaces left. Moof! ------------------------------ End of SPACE Digest V10 #18 *******************