From: skunk-works-digest-owner@mail.orst.edu To: skunk-works-digest@mail.orst.edu Subject: Skunk Works Digest V5 #585 Reply-To: skunk-works-digest@mail.orst.edu Errors-To: skunk-works-digest-owner@mail.orst.edu Precedence: bulk Skunk Works Digest Saturday, 30 December 1995 Volume 05 : Number 585 In this issue: re:Bentwaters Satellites, Stealth, and Space Debris See the end of the digest for information on subscribing to the skunk-works or skunk-works-digest mailing lists and on how to retrieve back issues. ---------------------------------------------------------------------- From: kerry@Hungerford.chch.cri.nz (Kerry Ferrand) Date: Sat, 30 Dec 1995 00:11:12 -1200 Subject: re:Bentwaters ummm call me stupid, but I can't see how the author makes the leap to alien ships crashing etc after seeing a single bent metal rod in a high security area. It could be a key part of some high-value weapons system or any number of classified things. Kerry ------------------------------ From: "Terry Colvin" Date: Fri, 29 Dec 95 18:24:32 EST Subject: Satellites, Stealth, and Space Debris Date: Thu, 12 Oct 1995 23:59:19 GMT From: Allen Thomson Subject: UCT 81214: Bright and stealthy A month or so ago we had a brief discussion of the feasibility and utility of stealth in LEO. At the time I opined that it might be worthwhile in tactical situations, but wouldn't be a good idea if the aim were to protect satellites from detection for long periods of time. The principal reason for this, IMO, is the very wide range of sensor types and viewing angles encountered by satellites in LEO and the fact that the stealth technologies which have been revealed to date apparently presuppose a known, fairly restricted set of "threat" sensors and engagement geometries. Thus things designed to be stealthy against one set of sensors might be detectable by other sensors the designers hadn't known about or couldn't take into account because of engineering constraints. As it happens, a concrete example of this has just come to light (so to speak). Several papers in the proceedings of the 1995 Space Surveillance Workshop* describe preliminary results of a orbital debris campaign sponsored by Space Command in late 1994. One of the interesting results concerned an object (UCT 81214) which was easily detected by a number of optical sensors but was basically invisible to most radars, some of them highly sensitive range instrumentation radars, operating from 217 MHz up to ca. 35 GHz. While 81214 probably wasn't intentionally designed to have low rcs -- I'd guess it's a just a stray fiberglass panel or something of the sort -- it nonetheless illustrates the point that monostatic-radar-stealthy doesn't mean optical-stealthy (and then there's IR, bistatic radar, lidar, etc). "Of special interest was data collected on object 81214. Initially detected by the ETS [Lincoln Lab optical sensors at White Sands], this object has a bright optical signature but appears very small to radar sensors, and may indicate the presence of many more objects of this type... "A considerable amount of data was collected on an interesting object. Satellite 81214 appears moderately bright to optical sensors, suggesting a large physical size. However, radar tracking on this object indicates that it is quite small. Millstone data at L-Band indicates a radar cross section of approximately 0.00003 square meters, suggesting an object with a small physical size. Several highly sensitive UHF radars have been unable to track this object, however. Even the telescope sensor at Anderson Peak, CA, that is normally not involved with satellite tracking had no difficulty tracking this satellite. The existence of this object and the data that has [sic] been obtained lend credence to the theory that there is a population of optically bright objects that appear quite small to a radar. In fact, it is possible that many of the unknown objects detected by optical sensors could fall into this area." 1994 Space Debris Campaign - Preliminary Results Taft DeVere, SenCom Corp. Tim Payne, SWC/AE Capt. Gary Wilson, HQ AFSPC/DOYY "[Kwajalein Missile Range] sensors participating in the 1994 Debris Campaign included ALTAIR (VHF, UHF), TRADEX (L- and S- band), ALCOR (C-band) and MMW (Ka-band), and SuperRADOT visible band optics... "The most interesting optical track was on object 81214, which was extremely bright to the SuperRADOTs, but was so small in radar cross section as to be untrackable by the radars at the 1756 km point of closest approach." Kwajalein Missile Range Contribution to the 1994 Debris Campaign A. Gerber, G. Duff, and D. Izatt MIT Lincoln Laboratory, Kwajalein Missile Range *Proceedings of the 1995 Space Surveillance Workshop 28-30 March 1995 Lincoln Laboratory Massachusetts Institute of Technology Lexington, Massachusetts K.P. Schwan, Editor Project Report STK-235, Vol.1 (ESC-TR-95-022) - ------------------------------ ------------------------------ End of Skunk Works Digest V5 #585 ********************************* To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "majordomo@mail.orst.edu". 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