Jul 17 1975
From The Space Library
Pioneer 10, launched 2 March 1972 and traveling out of the solar system at 43 200 km per hr, was operating normally despite a report that the spacecraft was making unexplained orientation changes [see 11 June]. The apparent changes were caused when, during a routine change in spacecraft orientation on 6 May, the spacecraft's star sensor made an undetected shift in its lock from the star Betelgeuse to the star Sirius. This shift twisted the frame of reference for measuring direction, and for changing the direction of spin-axis pointing. As a result, onboard and ground computers had recorded a gradual northward shift of the spin axis relative to the earth's motion around the sun. Also, when the thrusters were fired to move the spin axis with the earth's east-west course, "southward" impulses were necessary.
No loss of data had occurred, and techniques were being designed to verify star reference during intervals when the star sensor was used. (ARC Astrogram, 17 July 75, 1)
Two Ames Research Center research aircraft would be stationed in Hawaii for scientific research missions.
A U-2 earth-resources survey aircraft would probe the stratosphere up to 20 km to measure the distribution and extent of ozone, nitric oxide, and aerosol particles in the area between the equator and 40° N latitude. Conducted by ARC to aid a national study, the sampling program was part of a semi-global study of the effect of ozone and nitric oxide on the world's climate over a long period of time. Similar missions had been flown over higher latitudes and polar regions. Another objective of the U-2 flights was to collect remotely sensed data on the Hawaiian Islands in support of several investigations, including one of the decline and die-back of Ohia and Manami trees in the forested areas of Hawaii.
NASA's Kuiper Airborne Observatory, a C-141 jet aircraft equipped with a 91.5-cm infrared telescope, would make 16 flights to collect previously unobtainable data from the region of the galactic center, a highly complex intense source of infrared emission. (ARC Astrogram, 17 July 75, 1)
The International Telecommunications Satellite Organization's board of governors had authorized issuance of a request for firm fixed-price proposals for design, development, manufacture, and test of seven INTELSAT V satellites, with options for up to eight additional satellites. In 1979 INTELSAT V satellites would replace the INTELSAT IV- A series to be deployed in September 1975. INTELSAT V satellites would have increased capacity by a fourfold use of the 6/4 ghz frequency band, use of both antenna-beam separation and dual-polarization concepts; introduction of the 14/11 ghz band for limited coverage in high-traffic regions; and a maximum effective bandwidth of 2280 mhz. A single satellite design would be used in all three ocean regions of the INTELSAT global systems. INTELSAT V satellites were expected to have a capacity of 12 000 two-way voice circuits plus one color TV channel. (INTELSAT Release 75-8)
Lewis Research Center had awarded a contract to Rockwell International Corp. Rocketdyne Div. for a laser-heated rocket thrust chamber for spacecraft. The concept included transmitting laser energy from a ground laser-generating station to a spacecraft; propellant carried aboard the spacecraft would convert laser energy into propulsive thrust. The potential improvement in performance included a 400% increase in payload capability for a Space Tug.
Rockwell would build an experimental thruster, to be powered by a 10-kw laser beam and tested at LeRC using an in-house carbon-dioxide laser system, and would provide a preliminary design for a 5000-kw thruster. (Rocketdyne Release RD-16)
NASA announced appointment of Gerald D. Griffin as Deputy Associate Administrator for Operations in the Office of Manned Space Flight, effective 1 Aug. In his new position Griffin would plan for the most economical and flexible operation of the Space Shuttle and Spacelab. Griffin, who was Assistant Administrator for Legislative Affairs before this appointment, would be replaced by Dr. Joseph P. Allen, an astronaut assigned to the Astronaut Office at Johnson Space Center. (NASA anno 17 July 75)
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