 Space Operations |
In addition to the Shuttle/Mir docking flights (see pages 2-3), NASA conducted several important Space Shuttle missions in 1995/96 whose main objectives were scientific/technological rather than preliminaries to International Space Station assembly.
After four highly successful flights earlier in 1995, NASA launched STS-69, Orbiter Endeavour, on September 7 for a very demanding mission in which-for the first time-two separate payloads were deployed from the Orbiter and later retrieved.
STS-69 astronauts James S. Voss (foreground) and Michael L.
Gernhardt evaluated tools and techniques designed for on-orbit
assembly of the International Space Station.
The first was Spartan 201, the third Spartan mission in a planned series of four. Deployed on mission day two, Spartan 201 carried two scientific instruments for study of the Sun's outer atmosphere (corona) and its transition into the solar wind that constantly flows past Earth. Both instruments operated smoothly and both returned good data.
On flight day five, the Endeavour crew deployed the Wake Shield Facility-2 (WSF-2), a 12-foot-diameter disc designed to create an "ultravacuum" environment for growing electronics materials of significantly higher quality than can be produced on Earth. During its period of free flight, WSF-2 was able to perform four of seven planned thin film growth runs, despite attitude control problems.
On flight day 10, astronauts James S. Voss and Michael L.
Gernhardt conducted a six-hour-46-minute spacewalk. They tested
a variety of tools and techniques that may be employed in assembly
of the International Space Station and evaluated improvements
made to their extravehicular activity (EVA) suits. The STS-69
crew also covered a lengthy agenda of other experiments, including
growth of optical crystals and thin films with commercial potential
plus a variety of astronomical observations.
This wide view provides a perspective of the working environment
in the U.S. Microgravity Laboratory, flown aboard STS-73. At
left, working at the "glovebox," is mission specialist
Catherine G. Coleman, and at right is payload specialist Fred
Leslie, who is conducting a fluid physics experiment.
Shuttle mission STS-73, Orbiter Columbia, launched October 20, 1995, marked the second flight of the U.S. Microgravity Laboratory (USML), first flown in 1992. USML-2 built on the foundation of the prior mission, focusing in the same general areas of research, with many experiments flying for the second time. The Orbiter crew divided into two teams to work around the clock in the 23-foot-long pressurized Spacelab module mounted in the Orbiter's payload bay.
Research was conducted in five areas: fluid physics, materials science, biotechnology, combustion science and commercial space processing. Flying for the first time was a combustion experiment in which more than 25 droplets of a variety of fuels were ignited for study of how fuels burn in microgravity. In the Astroculture Plant Growth Facility, which is set to become a commercial system, small potatoes were grown from tubers, demonstrating that edible foods can be grown in space. A number of other experiments involved growth of crystals for post-mission study; crystals grown in orbit are generally larger and of higher quality than crystals grown in Earth facilities, offering potential for use in development of advanced pharmaceuticals or computer chips that are faster and use less power than traditional chips. STS-73 landed at Kennedy Space Center (KSC) after almost 16 days in orbit.
Working on experiments aboard STS-73 are payload commander
Kathryn C. Thornton (foreground) and payload specialist Albert
Sacco Jr.
The year's final mission, STS-74, Orbiter Atlantis, launched November 12, was devoted entirely to docking with the Russian space station Mir and subsequent joint U.S./Russian experimentation (see pages 2-3). STS-74 landed at KSC on November 20, rounding out a highly successful 1995 Shuttle agenda of seven missions.
The first Space Shuttle flight of 1996 was STS-72, Orbiter Endeavour, launched January 11, a nine-day mission highlighted by retrieval of a Japanese satellite that had spent 10 months in orbit, deployment and retrieval of a NASA science payload, and two spacewalks.
On flight day three, mission specialist Koichi Wakata of the
National Space Development Agency of Japan operated the Shuttle's
remote manipulator arm to pluck the Japanese Space Flyer Unit
from orbit. On the following day, Wakata again used the robot
arm, this time to deploy the NASA OAST-Flyer (Office of Aeronautics
and Space Technology), a free-flying platform with four experiments:
one testing the accuracy of computer models for predicting spacecraft
exposure to contamination; one demonstrating satellite-aided
global positioning; one testing laser ordnance devices; and an
amateur radio communications experiment. The OAST-Flyer was successfully
retrieved on flight day six.
This "fisheye" view shows astronaut Winston Scott
conducting a spacewalk during STS-72 in January 1996. The stowed
spacecraft in the rear of the Orbiter's payload bay are the Japanese
Space Flyer Unit, retrieved after 10 months in orbit, and NASA's
OAST-Flyer, retrieved after a two-day free flight.
Two extravehicular activities (EVAs) were conducted by mission specialists Winston Scott, Daniel T. Barry and Leroy Chiao as part of a continuing series of preliminaries to on-orbit assembly of the International Space Station. They evaluated a new portable work platform and a space station utility box designed to hold avionics and fluid line connects. Scott also tested the warmth of the EVA suit in temperatures as low as minus 104 degrees Fahrenheit.
Other experiments included use of a cargo bay-mounted instrument
for measuring ozone concentrations in the atmosphere, experiments
related to protein crystal growth, a National Institutes of Health
effort to validate models of microgravity effects on human bones,
muscles and cells, and a separate study of the effects of microgravity
on rodents.
This traditional in-flight crew portrait emphasizes the international
character of Shuttle flight STS-75. At bottom center is mission
commander Andrew M. Allen. Clockwise from him are payload commander
Franklin R. Chang-Diaz, NASA; Maurizio Cheli and Claude Nicollier,
representing the European Space Agency; pilot Scott Horowitz,
NASA; payload specialist Umberto Guidoni, Italian Space Agency;
and Jeffrey A. Hoffman, NASA mission specialist.
On February 22, NASA launched STS-75, Orbiter Columbia, on a reflight of the U.S./Italian Tethered Satellite Systems (TSS). The TSS is a tool for studying the power generation potential of a tethered satellite operating in the electrically-charged ionosphere. Deployed on flight day three, the TSS was gathering excellent data when the pencil-thin tether snapped; the satellite had almost reached full deployment 12.5 miles from the Orbiter.
The other primary payload on STS-75 was the U.S. Microgravity Payload-3 (USMP-3), which embraced a wide range of U.S. and international experiments in crystal growth and materials processing. USMP-3 performed nominally.
The year's third mission was STS-76, Orbiter Atlantis, launched March 22. The flight was devoted primarily to rendezvous and docking with the Mir space station, but it also included a lengthy agenda of U.S./Russian scientific experiments.
A view of the Tethered Satellite at the start of its deployment
from STS-75. The satellite was lost when the tether snapped but
the experiment provided considerable useful data.
On May 19 NASA launched the fourth flight of 1996, STS-77 Orbiter Endeavour. Primary payloads included commercial space product development payloads flying aboard the pressurized, commercially-developed SPACEHAB module (see page 24); an inflatable antenna experiment carried by the Spartan free-flying spacecraft; and four experiments called TEAMS (Technology Experiments for Advancing Missions in Space). TEAMS included an effort to determine the degree of accuracy with which the Global Positioning System can supply attitude information to a spacecraft; a test of improved methods for in-space refueling; an evaluation of liquid metal heat pipes in microgravity; and a demonstration of aerodynamic stability in the upper atmosphere.
At Spinoff publication time, STS-79, Orbiter Atlantis was being readied for mid-August launch to a fourth docking with the Russian Mir. A November mission, STS-80, Orbiter Columbia, was to feature the third flight of the WSF and in December Atlantis was to dock with Mir for the fifth time on STS-81.
