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{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/JNPSKOOL2JQFOR6WCWBM2KPADHQFWEBV/", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/", "message_id": "[email protected]", "message_id_hash": "JNPSKOOL2JQFOR6WCWBM2KPADHQFWEBV", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/JNPSKOOL2JQFOR6WCWBM2KPADHQFWEBV/", "sender": { "address": "K3IO (a) verizon.net", "mailman_id": "79a9b3ddaa4b44baae47f92374974ac4", "emails": "https://mailman.amsat.org/hyperkitty/api/sender/79a9b3ddaa4b44baae47f92374974ac4/emails/" }, "sender_name": "Tom Clark, K3IO", "subject": "[amsat-bb] Re: Government control has exceeded ...not really.", "date": "2007-04-26T07:17:10Z", "parent": null, "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "In this thread, Tom Davis asked\n> This raises an interesting possibility. The resolution of a 70cm radar is \n> rather limited for tracking the smaller but still dangerous debris. The Air \n> Force might propose a new higher frequency radar for this job. Will they? If \n> they do, would we support their request in Congress?\n> \n> Tom\nThe Air Force (USAF), thru MIT Lincoln Labs (LL), have several higher\nresolution radars at Millstone Hill, northwest of Boston, near the NH\nborder and at the junction of Westford, Tyngsboro and Groton townships.\nThe facilities there support several DoD radar programs, while the\n\"civilian\" side of the house is known as the Haystack Observatory (see\nhttp://haystack.edu/ for an overview of the facility). The Haystack\nObservatory activity on the hill is operated by MIT on behalf of NEROC,\na consortium of 8 universities (listed at\nhttp://haystack.edu/hay/neroc.html). [For full truth in advertising, I\nhave been a member of Haystack's extended family for many years, and I\ncurrently serve as an At-Large member of the NEROC Board of Trustees.]\n\nAt Millstone Hill, the USAF/LL has the 85' \"Millstone\" dish used as a\nhigh power surveillance radar at 1295 MHz. Some interesting info on\nDoD's various radars (including both Millstone & Haystack) can be found\nat\nhttp://www.ll.mit.edu/news/journal/pdf/vol12_no2/12_2detectsatellitiesplanets.pdf;\nsee Figure 26 for an aerial view of the entire facility.\n\nHaystack, Millstone and the smaller 60' \"Westford\" telescope were\noriginally built ~1960 by LL with USAF funding in order to bounce\nmicrowave signals off of a belt of passive, resonant dipole \"needles\" at\na time before there were any active communications satellites.Thousands\nof fine wire needles were embedded in a block of napthalene (think moth\nballs) so that they would be slowly and uniformly dispersed throughout\nthe orbit. A prototype of the needle dispenser is near the Oscar-1 model\nat the Udvar-Hazy museum. Yes, there is an in joke involving \"needles in\na haystack\".\n\nAs an aside, after the AO-10 and -13 launches and motor burns, NORAD's\nradars had troubles finding our satellites. With some quick round-trip\ntransponder & Doppler measurements, KA9Q & I were able to give Millstone\nenough orbital data so that could see our spacecraft at 10,000+ km and\nprovide Keplerian elements until NORAD got their act together.\n\nAt Haystack, there are two antennas. The larger is 37M (120') in\ndiameter and is under a rigid radome (it looks like a HUGE golf ball on\ntop of the hill!). This antenna has been used for a lot of astronomy\nprograms since the early 1960's. Until about 1972, a high-powered 8 GHz\ntransmitter and traveling-wave maser receiver were available for use as\na Planetary Radar to obtain spectacular \"photos\" of the Moon, Mars,\nVenus and Mercury; Haystack's Lunar images were invaluable to the Apollo\nastronauts Now it is equipped with a DoD high power 10 GHz radar\ntransmitter with ~1 GHz bandwidth. The 1 GHz bandwidth lets it be used\nto take a radar \"photograph\" of satellites with ~20 cm resolution\n(comparable to a wavelength at the 1 GHz spanned bandwidth).\n\nBeside the \"big\" golf ball is the smaller HAX (Haystack Auxiliary Radar)\nhoused in a smaller golf ball. HAX operates at Ku-band with its own\nforty-foot antenna, transmitter, RF hardware and receiver, but it\nshares control and signal and data processing systems with Haystack.\nHAX, which began operation in 1993, is the first radar to have a signal\nbandwidth of 2 GHz, which improves the range resolution to ~12 cm. HAX\nrepresents a significant advance in radar imaging capability, producing\nfiner and sharper images of satellites than the Haystack. In addition to\nits DoD sponsored imaging task, HAX has extremely useful in producing\ndetailed information for NASA on the locations, orbits and\ncharacteristics of space debris. For some comments on Haystack & HAX\ntracking debris see http://www.nasa.gov/home/hqnews/1994/94-136.txt\nand http://web.mit.edu/newsoffice/1995/needle-0208.html.\n\nThe new \"big project\" at Haystack is the refurbishment (really, nearly a\ntotal rebuild) to upgrade the Radar capabilities to a bandwidth ~10 GHz\nat P-band (90-100 GHz). Information on HUSIR(Haystack Ultra-wide\nSatellite Imaging Radar) can be found at \nhttp://haystack.edu/obs/haystack/LincolnUpgrade.pdf. With this new\nradar, images can be made with a few cm resolution.\n\nSo the answer to Tom's question is definitely YES, it is being done. I\nleave this question to your own imagination: Why would DoD want cm-level\n\"photos\" of stuff in orbit?\n\n73 de Tom, K3IO\n", "attachments": [] }