Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Fri, 3 Nov 89 05:37:13 -0500 (EST) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 3 Nov 89 05:34:58 -0500 (EST) Subject: SPACE Digest V10 #200 SPACE Digest Volume 10 : Issue 200 Today's Topics: Rocketry paper Re: Manned Jupiter Mission Re: More Info On NASP Fragile Space Shuttle Re: Manned Jupiter Mission Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989) Magellan Status for 10/31/89 [Corrected] (Forwarded) Re: Confederacy posting, copy received Galileo Status for 10/30/89 (Forwarded) Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989) ---------------------------------------------------------------------- Date: 1 Nov 89 17:40:49 GMT From: gem.mps.ohio-state.edu!uwm.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!bucc2!moonman@tut.cis.ohio-state.edu Subject: Rocketry paper I am doing a paper on the pre-Sputnik, post-1900 days of rocketry, & I'd like to know if there are any books on that subject. Please give any information to: uiucdcs\ noao>bradley!bucc2!moonman cepu/ Internet: bradley!bucc2!moonman@a.cs.uiuc.edu Arpa: cepu!bradley!bucc2!moonman@seas.ucla.edu Thanks a lot in advance. ------------------------------ Date: 1 Nov 89 17:50:24 GMT From: frooz!cfa.HARVARD.EDU@husc6.harvard.edu (Steve Willner) Subject: Re: Manned Jupiter Mission From article <1989Oct30.235627.6404@utzoo.uucp>, by henry@utzoo.uucp (Henry Spencer): [On stopping cosmic rays with magnetic fields] > One problem is that it's the very highest energies > that are the big worry; stopping the low 99% is not good enough. This must be a question of generation of secondary particles, not biological effectiveness of the primaries. (Biological effectiveness diminishes with increased energy.) Magnetic shielding generates many fewer secondaries than shielding with matter, since interaction with matter is what generates the secondaries. A quick calculation for the magnetic field strength necessary gives B=mvc/r, where B is magnetic induction ("magnetic field") in gauss, m is particle mass in grams, c is speed of light in cm/s, and r is desired radius of curvature in cm. (This is non-relativistic; for relativistic, just put gamma in front and note that v is nearly equal to c. I haven't looked this up, but I'm pretty sure it's right.) Putting in numbers for 100 MeV protons, I get only 10^-5 gauss to give a 1 meter radius of curvature, so the field strengths needed don't seem all that high, even putting in a distance^-3 dependence for dipole-like fields. (The implication is that magnet sizes must be of order one meter.) The pattern of fields to use is another question; I doubt a simple dipole would do much good. Does anybody have a good idea just what energies have to be stopped, bearing in mind that particles with higher energies will penetrate rather freely and will not encounter a massive shield? ------------------------------------------------------------------------- Steve Willner Phone 617-495-7123 Bitnet: willner@cfa 60 Garden St. FTS: 830-7123 UUCP: willner@cfa Cambridge, MA 02138 USA Internet: willner@cfa.harvard.edu ------------------------------ Date: Mon, 30 Oct 89 06:54:13 PST From: mordor!lll-tis!oodis01!riacs!rutgers!pnet01.cts.com!jim@angband.s1.gov (Jim Bowery) To: ucsd!nosc!crash!space@angband.s1.gov Subject: Re: More Info On NASP Larry Smith writes: >A big problem above Mach 7-8 now is what inefficiency percentage >do you assign to your scramjet engine model components, due to the >fact that above Mach 7-8, we have no real data to validate the codes? A whole bunch of us have been asking this question of NASP ever since its inception. Maybe the program is in so much trouble they finally decided to get real and try to validate all these marvelous computer models that are supposed to allow us to go from concept to flying prototype (X30) with virtually no emperical intermediates. Unfortunately, such validation will require emperical activities. *sigh* Ya just can't win em all. >Now this is NOT an indictment of scramjets, but it shows >the current REAL NEED to build HARDWARE to work some of these things >out. This is really the goal of X-30/NASP. NOT to build a Orient >Express, or a new SR-71, or even a payload orbiter. But, to >develop the required technologies to potentially build NASP Derived >Vehicles (NASPDV or NDV), and NASP Technology Derived Vehicles (which may >not be airplanes at all. ex: high L/D orbital transfer vehicles that >can do orbital plane changes with air breathing engines via the upper >atmosphere, new high Isp air breathing rockets, new cargo shuttles >without tiled skins). Right, Larry. They pull out the old viewgraphs that were used to sell the Shuttle as an operational vehicle capable of bringing the cost per pound to LEO down by a factor of 100 to 1000 after a development project of only $5 billion, and you think the real goal of NASP is to BUILD anything? The REAL GOAL of NASP is, as many of us who haven't forgotten history have been trying to tell the space nerds all along, to start yet another Big Development Project justified by chanting "WE HAVE THE TECHNOLOGY" before the appropriate subcommittees. After we have committed all our resources to the DEVELOPMENT of ONE idea, we decide to call it a "research" project, (sort of like the Shuttle not being expected to really be economical because it is a "research vehicle") other ideas can then try to find funding in an environment of vested interests, bureaucracy and political sleaze. What a way to run a science budget. --------------------------------------------------------------------------- Jim Bowery PHONE: 619/295-8868 BE A SPACE ACTIVIST PO Box 1981 GET OFF THE NET AND SET UP AN APPOINTMENT WITH YOUR La Jolla, CA 92038 CONGRESSMAN! --------------------------------------------------------------------------- UUCP: {cbosgd, hplabs!hp-sdd, sdcsvax, nosc}!crash!pnet01!jim ARPA: crash!pnet01!jim@nosc.mil INET: jim@pnet01.cts.com ------------------------------ Date: Wed, 1 Nov 89 20:33 EDT From: Nutsy Fagen Subject: Fragile Space Shuttle Okay, another question for you. Every time the shuttle goes up or comes down, I read about how just about every system is checked, removed, replaced, etc. I can understand a thorough checkout, and the fact that space travel is, to say the least, a risky business, but how much of what NASA does for turnaround would be considered unneccesary in 10-15 years (Provided the same shuttle design is still running). Few of us have a problem with a commercial plane ride in bad weather, yet we read that they can't even roll the shuttle to the pad because of rain! This also reminds me of just about every nut and fastener being traceable to who installed it, when, where it came from, etc. As I said before, I agree that such stringent measures are required at our current level of knowledge with space travel. What I am really wondering is how low until things start to 'ease off'. What will be the first requirements that get dropped? And, when will the astronauts get to stop wearing those uncomfortable orange suits? Mike Bunell MJB8949 @ RITVAX I R a student No boss No disclaimer no job ------------------------------ Date: 2 Nov 89 01:45:24 GMT From: calvin!johns@cu-arpa.cs.cornell.edu (John Sahr) Subject: Re: Manned Jupiter Mission In article <228@cfa.HARVARD.EDU> willner@cfa.HARVARD.EDU (Steve Willner) writes: >From article <1989Oct30.235627.6404@utzoo.uucp>, by >henry@utzoo.uucp (Henry Spencer): >[On stopping cosmic rays with magnetic fields] >> One problem is that it's the very highest energies >> that are the big worry; stopping the low 99% is not good enough. > >This must be a question of generation of secondary particles, not >biological effectiveness of the primaries. (Biological effectiveness >diminishes with increased energy.) Magnetic shielding generates many >fewer secondaries than shielding with matter, since interaction with >matter is what generates the secondaries. > > >A quick calculation for the magnetic field strength necessary gives >B=mvc/r, where B is magnetic induction ("magnetic field") in gauss, m ^^^^^^^ So close, and yet so far. This equation would be correct it the proton charge was included: B = mvc/(er) where e = 4.8x10^-10 cgs >is particle mass in grams, c is speed of light in cm/s, and r is >desired radius of curvature in cm. (This is non-relativistic; for >relativistic, just put gamma in front and note that v is nearly equal >to c. I haven't looked this up, but I'm pretty sure it's right.) >Putting in numbers for 100 MeV protons, I get only 10^-5 gauss to give [] ^^^^^ In the earth's lower ionosphere, where B is approximately 0.5 gauss, the Larmor radius for NO+ is about 200 cm. The magnetic field embedded in the solar wind has a typical size of a few times 10^-5 gauss, so no shielding would be necessary in the solar system if that was enough B. Plugging in that unfortunate factor of e changes that 10^-5 "gauss" to 2x10^+4 gauss, or 2 Tesla (for the MKSeoisie). Now, 2 T fields are possible today, but 2 T is big. Things that make 2 T fields in people sized volumes are large and heavy. You might be better off turning the darn magnet off and re-casting it into a shield. Save on the electric bill, too. my own opinions, of course.-- John Sahr, | Electrical Engineering - Space Plasma Physics johns@alfven.spp.cornell.edu | Cornell University, Ithaca, NY 14853 ------------------------------ Date: 31 Oct 89 17:32:38 GMT From: datapg!com50!questar!al@uunet.uu.net (Al Viall) Subject: Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989) In article <1989Oct30.235627.6404@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > In article <4772@mentor.cc.purdue.edu> f3w@mentor.cc.purdue.edu (Mark Gellis) writes: > >I've heard talk of using magnetic fields to deflect cosmic rays, particles, > >etc. This would supposedly lower the mass of the hull necessary to protect > >the crew of a spacecraft from radiation. Is this true? Workable? What is > >involved in setting up such a "radiation shield"? > > It's theoretically possible but complicated. The designs I'm aware of > for things like space colonies all use brute-force mass rather than > magnetic shielding. One problem is that it's the very highest energies > that are the big worry; stopping the low 99% is not good enough. > Much of the opinion of the late sixties and early seventies was that craft built for the long haul in the future would be better built out of the shell of a small asteroid. There are some interesting reports on using planetary objects as spacecraft. Although such a thing would take a herculean effort, this option would leave much for the shielding of cosmic rays. The mas would be there, the work would be hollowing it out, the problem would be propulsion. -- | INTERNET: al@questar.QUESTAR.MN.ORG | NEW PRODUCT ON THE MARKET | | UUCP: ..!amdahl!tcnet!questar!al | "Flame in a Can" | | FIDONET: 1/282:2,3 (Al Viall) | Just tear off the protective | | "MMMMMMM. And so good for you!" | seal, point and shoot. Great fun!| ------------------------------ Date: 2 Nov 89 01:15:34 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Magellan Status for 10/31/89 [Corrected] (Forwarded) MAGELLAN WEEKLY STATUS Oct. 31, 1989 CORRECTED: Pgh 4, It is the first software patch, not the first star scanner, as indicated. This is the weekly Magellan status report. Magellan on Tuesday, Oct. 31, was 80,889,686 miles from Earth. Having passed through perihelion on Oct. 7, the spacecraft is slowing as it begins its return to the orbit of earth and is now traveling at a speed of 83,205 miles per hour relative to the sun. With the exception of several failed star calibrations, Magellan continues to operate nominally during the second third of its cruise. None of the seven scheduled star calibrations performed last week provided a complete autonomous attitude update. On Oct. 24, although the star Beta Gruis was rejected due to the magnitude check, all four star crossings were found to be valid. The attitude control system analysts were then able to use the data to generate an attitude knowledge correction. It was tested and uplinked on Oct. 27. During the weekend, the command file to change star pairs was tested and is expected to be uplinked Thursday, Nov. 2. Additionally, the first software patch to help alleviate the star calibration problem was uplinked to the spacecraft today, Oct. 31. Preparations for Cruise load 14 and 15 are proceeding on schedule. The start of Cruise 14 stored sequence is scheduled for Nov. 6 and Cruise 15 on Nov. 28. SPACECRAFT Distance from Earth (mi) 80,889,686 Velocity Geocentric 66,573 mph Heliocentric 883,205 mph One-way light time (Oct. 30) 7 mins, 10 secs ------------------------------ Date: Wed, 1 Nov 89 14:53:19 CST From: Will Martin Subject: Re: Confederacy posting, copy received Thanks to Frank Paterra, I now have a copy of the Confederacy posting, and I've forwarded it to the SPACE moderator so it can get into the Digest without bouncing back out on USENET again. Regards, Will ------------------------------ Date: 1 Nov 89 20:53:54 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Galileo Status for 10/30/89 (Forwarded) GALILEO WEEKLY STATUS October 30, 1989 This is a weekly Galileo status report. Today, October 30, 1989, the spacecraft is about 2.5 million miles from Earth, and has gone 16.7 million along its 2.4-billion-mile spiral course to Jupiter. Its velocity around the Sun is almost 60,000 mph. All subsystems are working well. Since launch, operators have sent hundreds of real- time commands to the Galileo spacecraft. The S-band transmitter has been switched to 30 watts, and the propulsion system has been exercised twice in maintenance maneuvers (primarily to move oxidizer and fuel along in the plumbing.) The telemetry rate is 7.68 kilobits per second. As of this morning, the spacecraft is spinning at 2.9 rpm around an axis within 1 degree of the Sun line. As Galileo progresses around towards Venus, the Sun angle changes; this is held to less than 14 degrees, by commanded or automatic maneuvers, to assure a shaded spacecraft. The atmospheric entry probe was checked out last Thursday, October 26, and its condition is satisfactory. The imaging system and the near-infrared mapping spectrometer were checked out Friday, with good results. Preparatory activities for various other science instruments are being done, but the only instruments actually turned on and taking data are the magnetometer and the HIC. The heavy ion counter, an engineering instrument modified from parts of a Voyager cosmic-ray sensor, was turned on ten days ago and detected the latter part of the solar flare of October 19. Heavy ions of energies up to 130 MEV (million electron volts) have been detected, but the spacecraft has experienced no single-event upsets (i.e., no ill effects.) Today the star sensor on the spinning section is to be checked out, in preparation for Wednesday's start of dual- spin operations. The lower section of the Galileo spacecraft will be spun in reverse, with electric motors, stopping the rotation and despinning the science scan platform. The first trajectory-correction maneuver, TCM-1, is scheduled, in three instalments, for November 9, 10 and 11. ------------------------------ Date: 1 Nov 89 22:12:07 GMT From: agate!sandstorm.Berkeley.EDU!gwh@ucbvax.Berkeley.EDU (George William Herbert) Subject: Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989) In article <1989Nov1.175432.27191@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <660@visdc.UUCP> jiii@visdc.UUCP (John E Van Deusen III) writes: >>> Manned Jupiter missions could *really* *really* use better propulsion... >> >>After it comes around for the second time, intercept it with a high- >>performance, crew-carrying, orbital shuttle and make the comparatively >>quick journey in comfort and safety. > >"Comparatively quick"? Can you elaborate on this? Even after Galileo's >fiddling around in the inner solar system, its transit time to Jupiter >is still measured in years. Human exploration of the outer solar system >is difficult, verging on impractical, unless propulsion is good enough to >let you forget about economy orbits and use fast ones instead. A friend did a design for a contest for a manned jupiter mission. His solution was using NERVA rockets. Nothing else works, realistically. **************************************** George William Herbert UCB Naval Architecture Dpt. (my god, even on schedule!) gwh@ocf.berkeley.edu [maniac@garnet.berkeley.edu, but i don't check mail often] ---------------------------------------- ------------------------------ End of SPACE Digest V10 #200 *******************