Dec 16 1972
From The Space Library
Apollo 17 surface science press briefing was held at Manned Spacecraft Center as astronauts headed toward home from moon. Stanford Univ. seismologist Dr. Robert L. Kovach described results to date from lunar seismic profiling experiment. Experiment had recorded impact of lunar module (LM) on lunar surface 9 km (5.6 mi) southwest of landing site "right on target where we wanted it." Kinetic energy at impact was comparable to "1 ton of TNT going off." Signal was "very clearly recorded on the geophone array and we've acquired an extremely important data point; ... we're effectively getting a depth sample down to 3 to 4 kilometers [1.9 to 2.5 miles] in the Moon. And we should get some very important information about the underlying highland type materials." Data point was "in critical distance range to answer one of the mysteries ... of the shallow Lunar interior. We've been very much concerned about the enormous change in physical properties by terrestrial standards... velocity changes by enormous percentage over a very small pressure range." Data point should provide "answers as to just how these properties are changing."
Caution, the following audio files are each about 87MB, last over three hours and may take time to buffer
Click here to listen to Apollo 17 Mission Audio T+218.07 through T+230.57 Dec 16 1972 Sleep period (Long silences removed)
Click here to listen to Apollo 17 Mission Audio T+232.11 through T+236.02 Dec 16 1972
Click here to listen to Apollo 17 Mission Audio T+236.02 through T+238.42 Dec 16 1972
Click here to listen to Apollo 17 Mission Audio T+239.34 through T+242.42 Dec 16-17 1972
First two explosive charges deployed had not shown significant differences in subsurface of Apollo 17 landing site and those of Apollo 15 and 16 but Apollo 17 :site appeared to be "underlined by definitely more competent materials and they quite probably could be volcanic flows." Dr. Gary V. Latham, principal investigator for passive seismic experiment, said Apollo 17 data, when compared with previous data, suggested possibility of new interpretation of lunar structure. "We do find evidence for lunar crust as we did in the past, but we may have to thin it considerably." Velocity of seismic waves in crustal material and velocity of material underlying crust might also have to be lowered. "We're not dealing with pure anorthosite anymore. We're dealing perhaps with gabbros . and so we have ... to review all of the data and to reconsider our interpretations some, not just the seismologist, but the geochemist and geologist, as well."
Dr. Marcus E. Langseth of Lamont-Doherty Geological Observatory, principal investigator for heat flow experiment, said Apollo 17 experiment had "more than doubled" lunar heat flow data to date. "We've got a very successful emplacement in the operation of our instrument. It has been perfect." Lunar surface temperature recorded Dec. 14 had been about 360 K (189°F). At about 15 cm (6 in), it had dropped to 280 K (45°F). At about 65 cm (26 in) temperature dropped to 254 K (-2°F). "Below that depth, the temperature begins to increase again. It's about 257 degrees [3°F] at the bottom of the probes." Data indicated that heat flow at Apollo 17 site would resemble that observed at 15 cm (6 in). If so, it would "give support to the kind of growing model of a warmer interior to the Moon" and "would require that there be a total gradient abundance of radioactive isotopes in the Moon as compared to Earth. So, there would be implication here for fundamental difference in composition, between the Moon and the Earth."
Dr. Langseth also reported data from traverse gravimeter experiment had supported thesis that "high gravity anomalies associated with the mare basin-the so called mascons"-probably had been created by slab of basalt or lavas which had flooded into previously excavated basins. Dr. William R. Muehlberger of Univ. of Texas, principal lunar geology investigator, said Apollo 17 had provided "most exciting few days of my scientific career. This mission is truly the fitting climax to the whole Apollo program. The landing site held great promise that we were going to get a good chance to unravel much of the earlier lunar history as well as the sample and study of what appeared to be very young vulcanism.... And I think this promise was fulfilled." Orange materials at Shorty Crater had been "a spectacular plus." Scientists hoped "returned material will tell us that that was young vulcanism in volcanic alteration of Shorty Crater. There's still a possibility it could be an impact crater, however." Dr. Paul W. Gast, Chief of MSC Planetary and Earth Sciences Div., discussed Dr. Latham's suggestion that lunar crust might be thinner than originally expected: "I will certainly defend the proposition that the crust is made of a very aluminum plagioclase- rich rocks... anorthosite gabbro or gabbroic anorthosite... far from a basalt. I think that the chemistry of the surface rocks... and the returned rocks bear this out and if the crust is thin, it reduces the likelihood that it is any different composition than what we see at the surface." (Transcript)
Nearly half billion dollars worth of equipment, mostly junk, had been left on lunar surface during six Apollo landings, Chicago Tribune reported. List included rocket engines, electronic devices, golf ball driven by Apollo 14 commander Alan B. Shepard, Jr., feather left by Apollo 15 commander David R. Scott (who had dropped feather and hammer simultaneously during televised extravehicular activity to show that they both fell at same rate in vacuum), and 12 prs of boots costing $4000 a pair. Boots included those that Apollo 11 Commander Neil A. Armstrong had used to make first footprints on moon. Technological items left on moon included 5 S-IVB rocket engines costing $20 million each, 6 $40-million lunar modules, 3 lunar rovers at $2 million each, TV and photography equipment costing $5 million, 12 backpacks costing $3.6 million, and assorted tools valued at $600 000. Still operative on moon were five nuclear-powered scientific stations costing $25 million each and three laser reflectors costing total $2 million. (Kotulak, C Trib News Service, C Trib, 12/16/72)
December 16-January 22, 1973: West Germany's Aeros Aeronomy Satellite was successfully launched by NASA from Western Test Range at 3:25 PST by four-stage, solid-fuel Scout D vehicle. Spacecraft was placed in planned orbit with apogee of 864.4 km (537.1 mi) ; perigee, 218.1 km (135.5 mi) ; period, 95.47 min; and inclination, 96.95°. Primary objective was to place 127-kg (277-lb) payload in near- polar orbit to measure main aeronomic parameters of upper atmosphere and solar ultraviolet radiation in wavelength band of main absorption. By Jan. 22, 1973, all five experiments were performing satisfactorily and spacecraft housekeeping operations were normal, except that problem with synchronization of data rate to spin rate might degrade data from NASA's neutral atmosphere temperature experiment. Satellite, cylinder 71 cm high and 91 cm in diameter (28 by 36 in) with four telemetry antennas, would contribute to understanding of thermal, chemical, and dynamic processes governing atmospheric behavior. Instruments included mass spectrometer, retarding potential analyzer, impedance probe, extreme-ultraviolet spectrometer, and NASA's neutral atmosphere experiment. July 1965 agreement between West Germany and NASA had provided for series of cooperative satellite projects. Aeros, second in series, was agreed to in Memorandum of Understanding signed June 10, 1969. NASA was responsible for one experiment, Scout launch vehicle, launch, and limited tracking and data acquisition. West German Ministry for Education and Science (BMBw) was responsible for development of spacecraft and instrumentation and for operation and control of satellite after launch, as well as for four experiments. (NASA proj off; NASA Releases 69-91, 72-229)
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