Date: Mon, 11 Jan 93 05:02:47 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #034 To: Space Digest Readers Precedence: bulk Space Digest Mon, 11 Jan 93 Volume 16 : Issue 034 Today's Topics: ** BUSSARD RAMSCOOP ** Cheap Mars Rocks (was Re: Moon Dust For Sale) future space travel heat production of the sun HST Discovers Double Nucleus in Core of Active Galaxy Let's be more specific (was: Stupid Shut Cost arguements) Mars Observer Update - 01/08/93 (3 msgs) question on privately funded space colonization russian solar sail?+ Saving an overweight SSTO.... Soviet space disaster? Soviet space exhibit Supporting private space activities What Progress in Opening Up Galileo's Antenna? (was Re: Galileo Update - 01/08/93) 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: Sun, 10 Jan 93 12:18:45 PST From: Jason Cooper Subject: ** BUSSARD RAMSCOOP ** Newsgroups: sci.space chris@chrism.demon.co.uk (Chris Marriott) writes: > In article <7Pc3wB2w165w@tradent.wimsey.bc.ca> lord@tradent.wimsey.bc.ca writ > > >(if necessary) it might pipe protons out of the stream. Thirdly, if we > >were to STORE the antimatter, how would it be stored? I have seen methods > >for plasma, but can't seem to find antimatter storage. > > > >Any response welcome... > > > > Jason Cooper > > > > Storing antimatter should (in principle at least) be quite straightforward. > Assuming it's charged, you can both store it and move it using > magnetic fields. > > Chris > -- > -------------------------------------------------------------------------- > | Chris Marriott | chris@chrism.demon.co.uk | > | Warrington, UK | BIX: cmarriott | > | (Still awaiting inspiration | CIX: cmarriott | > | for a witty .sig .... ) | CompuServe: 100113,1140 | > -------------------------------------------------------------------------- > So, if we have an antiproton (p-bar, was it?) then does it have the SAME charge as a proton? Jason Cooper ------------------------------ Date: 11 Jan 93 07:07:45 GMT From: "David Hinz (hinz@picard.med.ge.com" Subject: Cheap Mars Rocks (was Re: Moon Dust For Sale) Newsgroups: sci.space,sci.astro,alt.sci.planetary Henry Spencer (henry@zoo.toronto.edu) wrote: : In article <1993Jan9.041013.27969@siemens.com> aad@siemens.com (Anthony Datri) writes: : >I must admit some skepticism wrt meteorites that are claimed to have been : >ejected from Luna and Mars. : : The evidence for the lunar meteorites is pretty convincing. The Mars ones : aren't as solidly established, but they're getting there. OK, someone has to ask... By what mechanism do these rocks get here? Volcanic action & random launching? How do they acheive escape velocity? Why do they end up so often in Antarctica? Or are they just more visible there? Do they come in swarms, or randomly? What is the meaning of life? ((oops, sorry, got into question mode, and, well, you know....)) -- Dave Hinz - Opinions expressed are mine, not my employer's. Obviously. Ask me if I have an opinion on this! \ Don't blame me; I voted for Perot! SAAB - Because you get what you pay for. \ Pherrets are Phun!!! ------------------------------ Date: Sun, 10 Jan 1993 22:49:36 -0600 From: pgf@srl03.cacs.usl.edu (Phil G. Fraering) Subject: future space travel \Mars will be the only real place for a large colony, but then again, /if there isn't anything there that's very interesting (like life or \fossils) I can't see large colonies being placed up there. You overlook the asteroids. A very big mistake. \Seems like the future will see expanding development of robotic systems /that will be used to explore every planet and moon, at a vastly \reduced cost over sending humans. But human costs could be lowered greatly too... in which case someone might go just for the heck of it. Britian would probably be willing to pay to send the current set of royals, one way... \Maybe in the next 100-200 years biology will advance to the point /where Venus could be altered with microbes. Change the atmosphere \so SOMETHING could live there. It would be interesting to see what /could live there if the temperature was reduced. Actually, as has been pointed out before on this forum, energy concerns make attempts to alter Venus untenable. _But_ that does not mean: \I think science fiction has given people a false sense of the possible. Not really. If anything, people have a too narrow sense of the possible. \The space travel fiction of over 100 years ago neglected things like /radio and computer electronics, and required a travelling human. \TEchnology has superseded the human, and the information can be /returned much more efficiently. Information... that's not quite what we're after. I can read travel book after travel book about New Orleans, none of which are likely to convey the experience of living there. \The urge to colonize the universe seems to come from an urge for /terretorial conquest that has been with us for a long time. It is \interesting how old themes are constantly repeated in the present. /It's too bad we can't interest some of our race (Serbians, Saddam, etc.) \in coveting lunar instead of earthly real estate. 1. I can visit New Orleans and enjoy it without wanting to conquer it. Exploration and colonization are not equivalent to conquest per se: the europeans had been in the northern part of the New World for at least a hundred years (and maybe more, depending on how far back before Columbus you're willing to go: The Basque are shifty and conniving in this matter) without any serious conflict with the natives. 2. The Serbians, and Saddam, don't really want land. They want power. If they can't kill or maim people in the process of taking said land, or otherwise strengthen their power, they aren't interested. They could do so in space exploration, but the rest of us are slightly hostile to the idea. Phil "No Fly Zone, No boost zone" Fraering -- Phil Fraering |"...Who in the valley shed the poison tear 318/365-5418 |no one knows... pgf@srl02.cacs.usl.edu|An old myth of a mythical hero..." ------------------------------ Date: Sun, 10 Jan 93 19:39:51 EST From: John Roberts Subject: heat production of the sun -From: clarke@acme.ucf.edu (Thomas Clarke) -Subject: Re: *** BUSSARD RAMSCOOP *** -Date: 5 Jan 93 19:25:07 GMT -Organization: University of Central Florida -> Not good enough, alas. The pressure at the *center of the Sun* produces -> only the most sluggish hydrogen reaction -- one that will take billions -> of years to consume the Sun's hydrogen supply. -I understand that a pile of human bodies (still alive somehow) as -large as the sun would have about the same mass, but would produce -more heat!! Let's see - using the numbers from the frequently-asked-questions post, the sun produces about 0.19 mW/kg. Unless I missed some decimal places, that's roughly 1/10000 of the per-kilogram heat production of humans. Of course, only a fraction of the sun's mass is undergoing fusion. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 10 Jan 93 18:54:34 From: Steinn Sigurdsson Subject: HST Discovers Double Nucleus in Core of Active Galaxy Newsgroups: sci.space,sci.astro In article <1993Jan9.011651.28731@s1.gov> lip@s1.gov (Loren I. Petrich) writes: In article <7JAN199317121606@kelvin.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: > "The galaxy's active core presumably harbors a black >hole which has been re-fueled by the galactic collision," >said Dr. Jack MacKenty, Assistant Scientist at the Space >Telescope Science Institute in Baltimore. I presume that what happens to a black hole in a galactic center is that it eats up all the stars on nearly radial orbits and tends to deprive itself of stars to consume, with new stars for it only arriving by their orbit parameters diffusing slowly to suitable parameters. Yes, see Begelman et al Nature 287 307, and review bu Shapiro in "Dynamics of Star Clusters" the black hole depletes a cone in phase-space that is repopulated on a relaxation time scale (long!) An incoming galaxy would not suffer this depletion of suitable stars, and would presumably have some stars going head-on into the hole, with many more to come. Did I get it right? Not quite, stars are not terribly efficient at fuelling AGNs - but galactic collisions are efficient at torquing gas to the galactic center, see eg Hernquist & Weil Nature 1992. * Steinn Sigurdsson Lick Observatory * * steinly@lick.ucsc.edu "standard disclaimer" * * The laws of gravity are very,very strict * * And you're just bending them for your own benefit - B.B. 1988* ------------------------------ Date: 11 Jan 93 06:18:51 GMT From: "Edward V. Wright" Subject: Let's be more specific (was: Stupid Shut Cost arguements) Newsgroups: sci.space In <1993Jan9.030346.9714@ptdcs2.intel.com> greason@ptdcs2.intel.com (Jeff Greason ~) writes: >>The "extreme mass ratio" is an aerospace legend. We've been >>building vehicles with similar mass ratios for the last 30 >>years. The Shuttle external tank has the right mass. So >>did the Saturn S-IVB stage. >I would love to see some convincing evidence of this, as this is the >key risk to SSTO in my opinion -- If I get sold of this, I'll try to >convince my Congresscritter. So, contact the National Technical Information Service, get the reports on Saturn Applications Single-Stage-to_Orbit, Chrysler SERV, etc., and read them. >1) A thermal protection system, capable of surviving multiple reentries > (many) suitable for reuse. On previous vehicles, this is ablative and > non reusable, or (on Shuttle), heavy and only marginally reusable. Nonsense. The first US ICBM warhead (Atlas) used a nonablative copper heat shield. Copper's too heavy for SSTO, but there are many newer refractory metals that would work just fine. The problem is not that there's no TPS available, it' choosing from among several alternatives. ------------------------------ Date: 11 Jan 93 02:19:47 GMT From: Steve Collins Subject: Mars Observer Update - 01/08/93 Newsgroups: sci.space,sci.astro,alt.sci.planetary I turns out that the Mars Observer flight software and the new Mac OS turned out to be almost identical in hex. The program can fulfill two such different applications because the Mars Observer SCP (spacecraft processor) interprets the code as Mil-Std 1750A instructions instead of motorola 680x0 instructions. The the coincidence was the source of much amusement when it was first discovered. It looks like the STAREX anomaly tiger team might recommend code changes that would cause the two programs to differ again, so we plan to continue our own development rather than waiting for the next Apple update... Steve Collins MO Spacecraft Team (AACS) ------------------------------ Date: 11 Jan 93 02:26:20 GMT From: Steve Collins Subject: Mars Observer Update - 01/08/93 Newsgroups: sci.space,sci.astro,alt.sci.planetary KaBLE is an engineering experiment to evaluate using Ka band to communicate to deap space spacecraft. It can potentially support much higher data rates than the X-band we currently use on MO. I don't know much about the details, but the transponder on MO can receive and return the signal under the right circumstances. There is a short window where we are on the High gain antenna but are close enough to have the link-margin to do the experiment. Steve Collins MO Spacecraft Team (AACS) ------------------------------ Date: Mon, 11 Jan 1993 03:42:19 GMT From: Dave Michelson Subject: Mars Observer Update - 01/08/93 Newsgroups: sci.space,sci.astro,alt.sci.planetary In article collins@well.sf.ca.us (Steve Collins) writes: > >KaBLE is an engineering experiment to evaluate using Ka band to communicate >to deap space spacecraft. It can potentially support much higher data rates >than the X-band we currently use on MO. I don't know much about the details, >but the transponder on MO can receive and return the signal under the >right circumstances. There is a short window where we are on the High gain >antenna but are close enough to have the link-margin to do the experiment. > > Steve Collins MO Spacecraft Team (AACS) I'm involved in some 20/30 GHz propagation work through ESA's Olympus Propagation Experiment and NASA's upcoming ACTS so I'm interested in MO's KaBLE, to say the least. This has caught me by surprise - in a pleasant way, of course. Where can I get some more information on the trials? (i.e., experiment objectives, etc.) Thanks. -- Dave Michelson davem@ee.ubc.ca ------------------------------ Date: Sun, 10 Jan 93 17:51:59 EST From: John Roberts Subject: question on privately funded space colonization -From: henry@zoo.toronto.edu (Henry Spencer) -Subject: Re: question on privately funded space colonization -Date: 10 Jan 93 05:34:23 GMT -Organization: U of Toronto Zoology -In article roberts@cmr.ncsl.nist.gov (John Roberts) writes: ->...Your complaint is that US citizens can't circumvent US safety ->regulations by going overseas. I don't see why they can't launch and also ->conform to the safety regulations. -John, are you under the impression that safety is the only reason why the -US government can refuse permission for a launch? No, I've also heard of government objections or theoretical objections to specific launch proposals on the grounds of national security, environmental impact, and (to a widely varying extent) protection of the domestic launch industry. (The last is not equivalent to forbidding overseas launches, since at least *some* foreign launches are generally permitted, and since a the hardware to be launched overseas could have been purchased in the US.) Herman did not specify which existing laws he was referring to, but my recollection from his posts of the last year or so is that one of his main areas of complaint has been US organizations being subjected to US safety regulations for foreign launches. I should have asked Herman to specify which legal points he objected to, not just safety regulations. -Would that it were so. -If you want to fly a plane, that's more or less true. But if you want to -launch a rocket, they can refuse permission because it is "not in the -national interest", they don't have to explain, and there is no appeal. I don't claim to be an expert on US politics and law, but I've read millions of words on those subjects, and I live in a part of the country where the working of the US government counts as "local news". I've heard of the US government blocking the activities of US citizens for many reasons, including the reasons I mentioned above, but I've never heard of any activity of US citizens being blocked by the US government with the official reason being given as quote it is not in the national interest unquote. Can anyone come up with a more concrete indication that such a legal provision exists exactly as stated, and perhaps some discussion on how it came about, and under which conditions it is likely to be used? -For example, for some years it was government policy that any private -remote-sensing satellite with ground resolution better than 30m would -be denied launch permission. That's on the grounds of military security, not some abstract, unspecified "national interest". Allen says that there's been a recent change in this particular policy, though I don't think he mentioned specific resolution limits. -One of the more interesting provisions of the late, lamented Commercial -Space Incentive Act was a clause exempting launches carried out under it -from DOT regulation *except* for safety. ->... And consider human rights issues - suppose ->US citizens set up a colony on the moon, and decide to revive the ->institution of slavery - would you say the US would have no legitimate ->interest in the matter? -Suppose we stack the deck the other way. US citizens set up a lunar -colony. The US then gets involved in a nasty little war in a country -named, say, Nam Viet, and reinstates the draft. Some of the residents -of the lunar colony are draft-age, and they are ordered to report to -an induction center. They refuse, noting that slavery was abolished -in the US over a century ago, and that the constitutional amendment -which did it made no exception for the US Army. The colony's government ----------------------- Let's assume for the sake of argument that what you mean is more or less equivalent to "national government" - so the colony is not just an activity by a US corporation, for instance - it's a political entity, which interacts with and makes agreements with the nations of Earth. -backs them, noting that the Neocommunist revolutionary movement in -Nam Viet presents no threat to the colony. Does the US have a legitimate -interest in *this* matter? Well, let's look at historical precedent. Suppose the lunar government has signed an extradition treaty with the US that includes extradition for draft evasion. Then the US has a right to expect the evaders to be returned (assuming they're still regarded as US citizens). If, however, the lunar colony (let's call it Adanac [Note1]) has signed no such treaty, then the US has little recourse to get the evaders back, and evaders who manage to escape from the US and get to Adanac can reasonably expect to be able to sit out the war, and perhaps even be pardoned several administrations later. Of course, if the US-Adanacians start building military bases and dropping rocks on the US, and this is condoned by the government of Adanac, then the US might be inclined to try use of economic or military pressure to alleviate the situation. To try to get the topic somewhat back on track, I interpreted Herman's post to suggest that Earth governments will always seek to control establishment of humanity off-earth, out of an evil desire to suppress human freedom. I theorized that if governments show an interest in the form of government chosen elsewhere, the motives are not necessarily always evil, and the results are not always guaranteed to be a net suppression of human freedom. [Note 1]: National anthem: "Adanac Ho!" John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 10 Jan 93 23:53:53 GMT From: David Goldschmidt Subject: russian solar sail?+ Newsgroups: sci.space henry@zoo.toronto.edu (Henry Spencer) writes: >Unfortunately, in the case of the heliogyro, there is a design constraint: >having to feather the blades adds awkward complications at the hub, since >now the hub ends of the blades must remain clear of each other through >a 90-degree pitch change. If you limit required pitch changes, the >packaging problems at the hub are simplified, because you can stack the >blades in multiple layers. Since you want a large number of wide blades >to compensate for the heliogyro's fundamental scaling disadvantage (area >scales linearly, rather than quadratically, with diameter), packaging >is a real problem at a modest-sized hub. With 90-degree pitch changes, >layers have to be separated by a full blade width. This must be solvable. First, there is no reason why all of the blades have to be attached to the hub at the same level (one could be above another) This allows you to overlap blades and retain full control over blade angle. Second, even if they were overlapping in the same plane, if you feather all the blades at once, and in the same direction, they shouldn't interfere with each other. (like a venetian blind.) I admit it sounds risky (what if blades catch?) but its no worse than any overlapping blades scheme. Another advantage of having 90 degree change is that it allows you to precess the axis of the sail easily. If you get the blades rotating with twice the period of the heliogyro, so they are all horizantal on one side of the disk and vertical on the other, this produce a constant torque with no additional control inputs. The only problem I see with this is a possible resonance in the blades - oscillations could build up with each revolution. Are there any other ways to precess the axis? The problem is that it is very difficult to tilt the entire blade at once on a useful time scale. By the time the blade is doing what you want, it has rotated around to the other side of the craft. (and is likely oscillating). Dave Patterson, guest on this account ------------------------------ Date: Mon, 11 Jan 1993 07:53:46 GMT From: "Gregory N. Bond" Subject: Saving an overweight SSTO.... Newsgroups: sci.space Suppose DC-X works more-or-less as planned, and they go ahead and attempt to build a DC-Y/DC-1. And suppose the pollyannas are right and it bloats and the dry mass goes up. There are a couple of scenarios here: 1) It's overweight by some relatively small amount, say, 5000lbs. This leaves 5000lbs payload, still a worthwhile cargo. And the price/lb is double projections, but still a small fraction of ELVs. So the project is still a win, albeit smaller. 2) The mass overrun is a substantial fraction of payload, or exceeds payload. Then a possibility would be to delete the life support and crew cockpit and use the thing unmanned. This should get enough mass back to get to case 1, perhaps with slightly lower reliability (due to automated operation). Costs would be higher than case 1 due to the need to buy replacement DC-1s that the robots have totalled that manned pilots wouldn't have, but could still be at least competitive with existing ELVs. The project is pretty much a wash, but valuable experience is gained. 3) The mass overrun is much larger than that. At this point, the project is lost; however I suspect that (given the findings of the various reports into the general feasability) this is much less likely than the previous cases. And in any case, you know a lot more than when you started, and you can do it right next time! Greg. -- Gregory Bond Burdett Buckeridge & Young Ltd Melbourne Australia Dizzy Gillespie: RIP. ------------------------------ Date: Mon, 11 Jan 1993 03:05:24 GMT From: Tom A Baker Subject: Soviet space disaster? Newsgroups: soc.history,sci.space,soc.culture.soviet >>Charles Packer (packer@amarna.gsfc.nasa.gov) wrote: >>: Somebody told me recently that they had read that the >>: former Soviet Union had suffered a space disaster in which >>: they had to leave one of their cosmonauts in orbit to die >>: because they couldn't rescue him. My informant said that >>: his information came from reading newspaper accounts of >>: formerly secret material that was made public in the last >>: couple of years during the unravelling of the Soviet system >>: and the subsequent increase in openness of discussion and >>: publication in Russia. Ahhhhh. During the Sixties there were indeed many persistant rumours about heartless Communist space scientists launching cosmonauts in unsafe capsules, and dead Soviets orbiting forever. These rumours never could be verified for my taste. I wish I could quote exact references, but this kind of stuff was sort of in the league of BOTH ufos and also propoganda. I remember reading a Reader's Digest story about two young Italian geniuses that loved to build radios. They eavesdropped in on Mercury flights, for instance, calculating the frequencies in use from a picture of the Mercury antenna. They also listened to Soviet flights, and tape recorded the cosmonaut's heartbeat. (Umm, you *DO* understand, don't you, that I am relating this possibly untrue story as an example of the "rumours"? I don't buy this tale, myself.) They took the tape to a doctor, and supposedly did not tell him what it was. "This is the heartbeat of a dying man," he was supposed to have said. The point is that there were lots of stories like this. Some even gave names of the poor bastards that died in orbit before Gagarin's flight. Put out for some Cold War reason, or just plain made up? Or true? Oh, well. --------------------------------------.-------------------------------------- Net - tombaker@world.std.com __ | National Space Society is a nonprofit uucp - uunet!world!tombaker / \ / | public organization dedicated to BIX - tombaker / O / | promoting the eventual establishment AOL - TABaker@aol.com / \__/ | of a spacefaring civilization. ______________________________________|______________________________________ ------------------------------ Date: Sun, 10 Jan 93 21:33:11 EST From: John Roberts Subject: Soviet space exhibit This week's episode of "Inside Space" on the Sci-Fi Channel showed the Soviet Space Exhibit in St. Louis. The report stated that this is the last of four cities visited by the exhibit, after which it is to be returned to Russia and disassembled. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Sun, 10 Jan 1993 15:14:46 GMT From: Marc G Fournier Subject: Supporting private space activities Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >In article dep+@CS.CMU.EDU (David Pugh) writes: >>The federal government paid the early airlines to carry mail. In some (most?) >>cases, these mail subsidies were the only thing that made the airlines profitable. >>So ... it seems reasonable to wonder if a similar program could be done for the >>private launcher market. What I'm proposing is that the government agree to pay >>$1000/lbs to deliver 1 million pounds to LEO each year from 1995 to 2015. At >>$1 billion/year, this would be a fairly small program (by government standards). > >Congratulations, you've reinvented (more or less) the Commercial Space >Incentive Act, which was proposed a few years ago. Congress didn't like it >and it didn't get anywhere. > >Even if you could get it passed, there is the non-trivial problem of >convincing would-be launcher developers that it won't get repealed during >their development period. It *is* a relatively small expense, and it >almost certainly *would* be extremely effective, but it's not the way >Congress likes to do things. > >>... (I realize, of course, >>that NASA would ever let it pass no matter what we did to it)? > >It's not NASA's decision. Congress has passed bills that NASA didn't like. >Forget NASA; the hard part is selling it to Congress. I'm confused. Is the US the only country that has the 'environment' to set up a launch site? My understanding about why it is all done from Florida is that it has to do with weather and easy of escaping Earth's atmosphere (lower gravity?) Now, I know that the USSR(don't know which part has it now) has a space program, and that there are a few other countrys that also have their own space programs. If the private sector was willing to/were to be convinced to fund a private space program...why is the US the only place to do it? Where their rules/laws/whims are followed? Marc -- Marc G. Fournier | R-node Public Access Unix running Linux 0.99p1 Etobicoke, Ontario | 416-249-5366 24hrs 7 days/week network email voice: 249-4230 | shell accounts available 2500+ newsgroups FREE marc@r-node.pci.on.ca | Telebit WorldBlazer/SupraModem2400/Cardinal 2400 ------------------------------ Date: Mon, 11 Jan 1993 03:20:17 GMT From: "Loren I. Petrich" Subject: What Progress in Opening Up Galileo's Antenna? (was Re: Galileo Update - 01/08/93) Newsgroups: sci.space,sci.astro,alt.sci.planetary In article <9JAN199318252344@kelvin.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: >10. On December 29, after approximately 20 hours at the warming attitude, the >DDA-5 windup/hammering activities commenced at 1455 UTC. A total of 2160 >hammer pulses were executed along with three 20 second windup sequences. Data >analysis indicated the ballscrew rotated approximately 360 degrees for a total >ballscrew rotation beginning with the initial deployment attempt of >approximately 6.4 rotations. There was no indication of a rib release >(see Special Topic No. 2). 1 rotation added to 6.4 rotations. Not bad. >11. On December 30, the spacecraft, under stored sequence control, was >commanded back to a 5 degree off-sun attitude at approximately 1048 UTC. >After the sun acquisition, sun gate data was collected to determine if an >antenna rib is still obscuring the sun gate signal. Preliminary data >analysis indicates that the sun gate field of view is still obscured although >the signature appears to have changed. Initial analysis indicates that rib >No. 2 may have moved out to a 43 degree angle. Also, preliminary results may >indicate that the antenna mesh is covering the sun gate field of view. "Rib No. 2"? What rib it is does not have much meaning unless one knows which are the stuck ones. It was reported that 2 or 3 ribs had been stuck. If one of them is now unstuck, then it's 1 or 2 to go, I suppose. Moving out to a 43-degree angle? Is that the angle that the already-open ones are out to? "Signature appears to have changed" -- what's that? > Additionally, real-time commands were sent to open the star scanner (SS) >shutter, reacquire celestial reference, and select scan type 6 to perform >precise wobble estimation. The wobble estimate indicated a change of 0.3 >milliradians which collaborated the motor current data indicating that no >ribs released (see Special Topic No. 2). This change of 0.3 milliradians would presumably mean that the ellipsoid of inertia has changed by some comparable fraction. I'm not sure about Galileo's weight and dimensions, but I would presume that if the spacecraft weighs 1 ton, then this wobble change corresponds to a motion of a mass of about 300 grams across the dimensions of the spacecraft. > After approximately two hours at the warming attitude, hammering of the >HGA (High Gain Antenna) motors commenced. Five 180 hammer pulse sequences >were sent beginning at 2225 UTC and ending at 0442 UTC. The motor hammering >sequences were executed with the HGA motor temperature at 19.3 degrees C, >29.8 degrees C, 34.4 degrees C, 36.2 degrees C, and 40.6 degrees C. >Preliminary analysis indicated that the ballscrew was stalled with no >appreciable ballscrew rotation. There was some suggestion of minor rotation >with the HGA motor temperature at 29.8 degrees C. There was no indication of >a rib release (see Special Topic No. 3). Disappointing. [Later such HGA motor hammering mentioned...] Any further results? -- /Loren Petrich, the Master Blaster /lip@s1.gov ------------------------------ End of Space Digest Volume 16 : Issue 034 ------------------------------