Daily News Friday, July 31, 1992 24-hour audio service at 202/755-1788 % Atlantis launches at 9:56 am to start Tethered Satellite mission; % European Retrievable Carrier to be deployed tomorrow morning; % Tethered Satellite System check out is Sunday, deploy is Monday; % Oshkosh Air Show begins today, NASP 50-foot mockup featured; % Marshall to host Space Station Freedom users conference next week; % STS-47 flight crew inspects Endeavour & Spacelab-Japan experiments. Like clockwork, Atlantis lifted off this morning right on time at 9:56 am EDT to begin the STS-46 mission. The ascent into exceptionally clear Florida skies was absolutely nominal. First and second stage performance were right on the money. Atlantis is now in a circular 267-statute-mile-high orbit. The flight crew will spend the afternoon activating the European Space Agency's European Retrievable Carrier spacecraft and then deploy it from the payload bay early tomorrow morning. On Sunday, the STS-46 crew will begin to carry out a series of experiments with the Tethered Satellite System. The Italian-built TSS satellite will be deployed on Monday. This will be the first time a satellite has ever been deployed on a long tether in space. The Tethered Satellite will be extended to a distance of 12-1/2 miles from Atlantis. Mission commander for this flight is Loren Shriver, who is making his third shuttle flight. Pilot is first-timer Andy Allen. Mission specialists for the flight are NASA astronauts Marsha Ivins, making her second flight, and Jeff Hoffman and Franklin Chang-Diaz, both making their third flights, and ESA astronaut Claude Nicollier, making his first flight. Franco Malerba, Italian Space Agency, is the payload specialist for this mission, his first flight. The Tethered Satellite System will be used in a series of tests to determine if it is feasible to use such a system for generating electricity for such structures as Space Station Freedom. When the Tethered Satellite is fully deployed, the combination of Tethered Satellite and shuttle orbiter, both connected by the electrically- conducting tether, will be acting as an electrical generator as they move in orbit through the Earth's magnetic field lines. The expected voltage potential between the two spacecraft is on the order of 5,000 volts. The mission is scheduled for 6 days, 22 hours and 11 minutes with a planned end-of-mission landing at the Kennedy Space Center's Shuttle Landing Facility on Friday, August 7. This is the 12th flight for Atlantis, which last flight was the Atlas-1 mission this past March and April. * * * * * * * * * * * * * * * * The Experimental Aircraft Association Fly-In opens in Oshkosh, Wisconsin, today, and will stay open through next Friday, August 7. The NASA pavilion will feature a 50-foot-long mock-up of the National AeroSpace Plane which was designed and built by students at Mississippi State University. The NASA exhibit will also focus on the Agency's work in the area of high-speed civil transport. The two-trailer Space Station Freedom habitation and laboratory module exhibit will also be parked by the NASA pavilion. The space station display allows visitors to walk through high-fidelity mockups of the U.S. habitation and laboratory modules. * * * * * * * * * * * * * * * * NASA will hold the first Space Station Freedom Utilization Conference next week in Huntsville. The purpose of the conference, set for Monday through Thursday, August 3 through 6, is to inform potential researchers about Freedom capabilities, plans and opportunities for research and to provide an open forum for exchange of information and ideas between space station managers and potential space station investigators. As part of the forum, experienced researchers who have flown equipment aboard Spacelab will describe their experiences and learned lessons. Further information on the conference can be obtained from Barry Epstein, NASA Headquarters, 202/453-8203, or Deb Gilman, BDM International, at 202/479- 5250. The seven astronauts scheduled to fly aboard Endeavour for its September Spacelab-Japan science mission, Wednesday inspected the Spacelab module and conducted their final pre-launch inspection of the module's experiment racks. The crew entered Endeavour and then using the airlock tunnel, crawled into the Spacelab for their inspection. The next milestone for that mission is expected to occur mid-August when Endeavour is moved from the Orbiter Processing Facility to the Vehicle Assembly Building. * * * * * * * * * * * * * * * * In yesterday's edition it was not made clear why "star calibrations and momentum wheel desaturations" are necessary for Magellan if it is not actively mapping Venus. The nominal Magellan orbit consists of two major elementsPa Venus-facing portion and an Earth-facing portion. Magellan maneuvers back and forth during each orbit to accommodate the Venus- facing requirement for radar mapping and the Earth-facing requirement for transmission of the radar data. Magellan uses three reaction wheels, or gyroscopes, to control the spacecraft's attitude in relation to Venus. There is one reaction wheel for each of the spacecraft's three axes P yaw, pitch and roll. To counteract a spacecraft motion in one of these axes, the gyro for that axis is spun up. The reaction wheels, driven by electric motors, are used to store momentum while they are spinning. During each orbit, Magellan's thruster motors are fired to counteract the torque being applied to the spacecraft as the gyroscopes are then despun. Despinning eliminates momentum which had been stored during the orbit. This process is referred to as "momentum wheel desaturation." During this same orbital period, Magellan uses its onboard star trackers to look at the position of two stars and compare their location with its onboard star map. This allows the attitude and guidance system to maintain a fix relative to Venus. These two operations are executed routinely each orbit. During Magellan's current operating sequence, the radar instrument and data recording systems are not being used while Jet Propulsion Laboratory flight controllers determine the best procedure for using the spacecraft's high-rate data transmitter system. There are several sections of the planetary surface which have not yet been mapped and JPL Magellan controllers are fine tuning procedures which will be used later this summer to ensure that data of those regions are transmitted with the least likelihood of noise or other problems corrupting the data. In the meantime, Magellan's orbital housekeeping functions such as star calibrations and gyro despinning continue nominally. Here's the broadcast schedule for Public Affairs events on NASA Select TV. Note that all events and times may change without notice, and that all times listed are Eastern. Live indicates a program is transmitted live. Friday, July 31, 1992 Live 6:00 am Launch coverage of Atlantis for STS-46 Tethered Satellite and Eureca deploy mission begins from KSC. Live 9:56 am Scheduled launch of Atlantis for STS-46 mission. 10:09 am Replay of launch videos. Live 11:00 am Post-launch press conference from KSC. Live 1:01 pm Tethered Satellite System structure check, from Atlantis. Live 5:26 pm TSS retention latch function check, from Atlantis. Live 10:23 pm Unberthing of the European Retrievable Carrier, from Atlantis. Saturday, August 1, 1992 Live 12:40 am Eureca solar array and antenna deploy, from Atlantis. Live 3:51 am Eureca release from payload bay, from Atlantis. Live 9:00 am Mission status briefing, from JSC. 9:30 am Replay of Flight Day 1 activities. 11:30 am Replay of Flight Day 2 activities. Sunday, August 2, 1992 Live 7:51 am Cabin TSS operations, from Atlantis. Live 2:51 pm TSS science operations, initial beam emission test, from Atlantis. Live 3:30 pm Mission status briefing from JSC. Live 4:16 pm TSS science operations, orbiter fluorescence observations, from Atlantis. 11:30 pm Replay of Flight Day 3 activities. Monday, August 3, 1992 Live 11:41 am Pre-deploy operations for Tethered Satellite System, from Atlantis. Live 12:50 pm Tethered Satellite System boom extension, from Atlantis. Live 2:29 pm Tethered Satellite System deploy and flyaway, from Atlantis. Live 10:00 pm Mission status briefing from JSC. 11:30 pm Replay of Flight Day 4 activities. This report is filed daily at noon, Monday through Friday. It is a service of NASA's Office of Public Affairs. The editor is Charles Redmond, 202/453-8425 or CREDMOND on NASAmail. NASA Select TV is carried on GE Satcom F2R, transponder 13, C-Band, 72 degrees West Longitude, transponder frequency is 3960 MegaHertz, audio subcarrier is 6.8 MHz, polarization is vertical.