High Resolution Microwave Survey
The High Resolution Microwave Survey (HRMS) was a NASA SETI project to search for microwave signals coming from an extraterrestrial intelligence. It consisted of two elements: an all-sky survey and a targeted search. The former, conducted by the Jet Propulsion Laboratory, was to observe the entire sky over the 1 to 10 GHz frequency range, plus spot bands up to 25 GHz. This was to explore the possibility that there might be civilizations transmitting strong signals, possibly as interstellar beacons. The Targeted Search, conducted by the Ames Research Center, was a high sensitivity search, in the 1 to 3 GHz range, to look for weak signals originating near Sun-like stars within a distance of 100 light-years (30 pc). A 10 millionfold increase in capability over the sum of all previous searches was anticipated through the use of high-performance data processing equipment known as the Multi-Channel Spectrum Analyzer (MCSA).
The HRMS began its observational phase on October 12, 1992 at the NASA Goldstone Deep Space Communications Complex (All-Sky Survey) and the Arecibo Observatory (Targeted Search). In a coordinated program, the Arecibo antenna was pointed at the star Gliese 615.1A and the Goldstone antenna began to scan a small area of the sky that included the position of the target star. During the following year, the All-Sky Survey team continued observations at Goldstone on a part-time basis while continuing to build the operational system with 16 times the capability. The Targeted Search team returned from Arecibo after the scheduled two-month observing session and disassembled the system for upgrades and expansion. In October 1993, the US Congress voted to discontinue financial support for NASA's SETI program and HTMS was canceled. Subsequently, however, the Targeted Search portion of HTMS was rescued through the intervention of the SETI Institute and was re-launched as Project Phoenix.
1. Dick, S. J. "The Search for Extraterrestrial Intelligence and the NASA High Resolution Microwave Survey (HRMS): Historical Perspectives," Space Science Reviews, 64, 93 (1993).