Aucbvax.5658 fa.space utzoo!decvax!ucbvax!space Tue Dec 29 03:35:24 1981 SPACE Digest V2 #73 >From OTA@S1-A Tue Dec 29 03:19:25 1981 SPACE Digest Volume 2 : Issue 73 Today's Topics: Cables to an SPS Cables to an SPS Otrag pulls out of Libya ---------------------------------------------------------------------- Date: 29 December 1981 02:12-EST From: Robert Elton Maas Subject: Cables to an SPS To: p-btempl at CCA-UNIX cc: SPACE at MIT-MC Date: 26 Dec 1981 00:05:43-EST From: p-btempl at CCA-UNIX (Brad Templeton) It occurs to me that even aiming at a reception station just above the atmosphere for cable transmission down to earth would not stop the complainers - it might cause them to complain more. If the SPS is at geosync orbit, then a station a few hundred miles up is effectively on the earth for most of the rotation cycle, so there would be lots of earth beyond the path of the beam, and worst of all, not just one place (like the desert) Instead a whole circle of danger is sweeped out if any leakage occurs. This doesn't make sense. If the station a few hundred miles up is in normal orbit or otherwise moving with respect to the Earth, there's no way to connect a cable between the station and a fixed point on the Earth, which was the original idea of mine. On the other hand, if the station is fixed with respect to the Earth, as I intended, the geometry is fixed, the beam from the synchronous-orbit SPS always is aimed at the same place on or off the Earth. It can be arranged for the low-relay-station to be a quarter revolution away from the SPS (with respect to center of earth) so that the beam from SPS to relay-station is essentially tangent to the Earth, missing it at all times. My original idea was to run the cable all the way from the SPS to the Earth, but I think the relay-station idea is a viable alterntive which doesn't involve part of the beam passing the relay station and striking the Earth. Only the side lobes have a chance of striking the Earth, and with the relay station several hundred miles from the Earth the side lobes reaching the Earth can be made insignificant. ------------------------------ Date: 29 December 1981 02:41-EST From: Robert Elton Maas Subject: Cables to an SPS To: p-btempl at CCA-UNIX cc: SPACE at MIT-MC I don't see anything wrong with inventing a cheap way to put bulk materials into space and then reserving the shuttle for humans and fragile cargo. Thus the linear accelerator could be useful even though it works only for bulk cargo, reducing the need to reserve the shuttle for such loads, leaving it more free for other stuff. If delicate cargo can be packaged correctly so it can withstand the jarring of the accelerator, and if it's not too delicate to withstand the average acceleration, then even delicate cargo can be sent by accelerator. Here's another idea I just thought of. How about a rotating catapult in a vacuum chamber. There's a door that opens for a moment just as the load is released from the catapult and then closes quickly so not much air gets into the chamber. The reason for the chamber is so the catapult can spin up to speed without encountering much air friction. The whole contraption could be installed on a high mountain top or flown up in a baloon, so the air outside the chamber has much less pressure than sea-level, and the air inside could be a factor of ten lower pressure. The combination of high initial speed (because of spinning-up the catapult in a near vacuum) and nearness to the top of the atmosphere (because of location) possibly means a good shape (low friction, low turbulence) and a thin ablative coating would enable tossing up to a 100-mile altitude where a spacecraft could catch the projectiles and toss them to higher orbit etc. There would be a high velocity difference between the projectile and the orbiting relay (catch&re-toss) station, but that's easy to handle, just have a long arm that catches the projectile while withdrawing at high RPM (like the way a baseball player catches a fly ball) and then just rotates around (at constant RPM) to another position where it lets go of the projectile. Thus the catch&re-throw catapult has to withstand only centrifugal force while actually handling the load, no tangential force. The force while spinning up preparatory to catching the load and while spinning down afterward is small (the computer can plan the catch a quarter to half orbit ahead of catch-time, i.e. as soon as it's released from Earth, then make minor adjustments in the spin-up as the projectile is tracked on its way up from Earth, making the spin-up quite smoothe. Note that the axis of the catapult-spin, the distance of the catcher from the pivot point, and the RPM, can all be controlled, achieving a perfect catch, the projectile exactly striking the catcher and the velocities of the projectile&catcher being zero at the moment of catching). ------------------------------ Date: 29 Dec 1981 00:14:15-PST From: decvax!duke!unc!smb at Berkeley In-real-life: Steven M. Bellovin To: decvax!duke!unc!space@Berkeley Subject: Otrag pulls out of Libya Cc: POURNE@MIT-MC Otrag, a West German company that has been developing rockets with potential military applications, has halted testing work in Libya. They began withdrawing personnel and abandoning their launching base about two months ago. American intelligence sources indicated that the company was using its ostensibly peaceful rocket program to mask efforts to sell military technology, including short-range rockets, to Libya, Pakistan, Iraq, and other countries; the company has denied such reports. Sources claim that the pullout followed an internal battle, in which Lutz Kayser, an aerospace engineer who founded the company, was fired. Kayser is reported to have remained in Libya, and is still working on missle development. The company now says it will refrain from developing its own launch facilities, instead using launch sites operated by other countries or international groups. "This will help eliminate the political problems of Otrag-owned sites," said Frank Wukasch, president of Otrag. From a N.Y. Times News Service article ------------------------------ End of SPACE Digest ******************* ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.