On November 3, 1994, the space shuttle Atlantis embarked on its 13th mission into the vast expanse of space. This mission, known as STS-66, was a significant step in NASA’s ongoing exploration of Earth’s atmosphere and its interaction with solar energy. The 11-day mission was led by a team of skilled astronauts, including Commander Donald R. McMonagle, Pilot Curtis L. Brown, Payload Commander Ellen Ochoa, and Mission Specialists Joseph R. Tanner, Scott E. Parazynski, and Jean-François Clervoy, who represented the European Space Agency (ESA).
Mission Overview
The primary objective of STS-66 was to operate the third Atmospheric Laboratory for Applications and Sciences (ATLAS-3) and to deploy and retrieve the U.S.-German Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere-Shuttle Pallet Satellite (CRISTA-SPAS). These instruments were part of NASA’s Mission to Planet Earth, a program aimed at understanding how the Sun’s energy affects Earth’s climate and atmospheric composition.
The Crew and Their Roles
Each member of the STS-66 crew brought unique expertise to the mission. Commander McMonagle, selected as an astronaut in 1987, was on his third space flight, having previously flown on STS-39 and STS-54. Pilot Brown, also from the 1987 astronaut class, had previously participated in STS-47. Payload Commander Ellen Ochoa, selected in 1990, had experience from the ATLAS-2 mission, STS-56. For Mission Specialists Tanner, Parazynski, and Clervoy, all from the class of 1992, STS-66 marked their inaugural journey into space. Clervoy had initially been selected as an astronaut by the French space agency CNES in 1985 before joining ESA in 1992.
The Science Behind the Mission
The ATLAS-3 payload was equipped with a suite of scientific instruments designed to measure various atmospheric parameters. The instruments on board included the Atmospheric Trace Molecule Spectroscopy (ATMOS), Millimeter-Wave Atmospheric Sounder (MAS), Active Cavity Radiometer Irradiance Monitor (ACRIM), Measurement of the Solar Constant (SOLCON), Solar Spectrum Measurement (SOLSCAN), and Solar Ultraviolet Spectral Irradiance Monitor (SUSIM). These tools were mounted on a Spacelab pallet and the shuttle’s payload bay sidewall, enhancing the mission’s scientific capabilities.
The CRISTA-SPAS satellite, which was deployed and later retrieved during the mission, housed instruments like the CRISTA and the Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI). These tools were crucial for studying the Earth’s middle atmosphere, providing valuable data to complement findings from earlier missions, ATLAS-1 and ATLAS-2.
Atlantis Prepares for Launch
Before the STS-66 mission, Atlantis underwent significant modifications at the Rockwell plant in Palmdale, California. These included installing cables and wiring for a docking system intended for the first Shuttle-Mir mission in 1995. Atlantis was also equipped to handle Extended Duration Orbiter missions lasting two weeks or more, and it received upgrades like improved nose wheel steering and a reusable drag chute. Once these modifications were complete, Atlantis was rolled out to Launch Pad 39B at NASA’s Kennedy Space Center (KSC) in Florida for its upcoming mission.
Liftoff and Orbit
On November 3, 1994, after a brief delay due to high winds at one of the Transatlantic Abort sites, Atlantis successfully launched into space at 11:59 a.m. EST. This marked the third shuttle launch in just 55 days, narrowly missing a record set in 1985. The shuttle reached a 190-mile orbit with an inclination of 57 degrees to the equator, allowing the crew to begin their ambitious scientific endeavors.
Upon reaching orbit, the astronauts opened the payload bay doors, deploying the shuttle’s radiators and stowing their launch and entry suits for the duration of the mission. They quickly transformed Atlantis into a fully operational science platform.
Conducting Science in Space
The crew was divided into two teams, Red and Blue, to ensure around-the-clock operations. The Red Team, consisting of McMonagle, Ochoa, and Tanner, activated the ATLAS-3 instruments, the CRISTA-SPAS satellite, and the shuttle’s Remote Manipulator System (RMS) shortly after reaching orbit. Meanwhile, the Blue Team, comprised of Brown, Parazynski, and Clervoy, took their rest period to maintain the crew’s efficiency throughout the mission.
One of the mission’s highlights was the deployment of the CRISTA-SPAS satellite. Operated by Clervoy using the RMS, the satellite was released from its cradle and sent on an eight-day free flight to collect atmospheric data. Atlantis then maneuvered to a safe distance from the satellite using its thrusters.
Experiments and Observations
Throughout the mission, the astronauts conducted a series of experiments in the shuttle’s middeck and payload bay. These included protein crystallization experiments, evaluations of heat pipe performance, and a student experiment aimed at studying the Sun, complementing the ATLAS instruments. The crew also monitored the shuttle’s microgravity acceleration environment, which is crucial for understanding how microgravity affects various physical processes.
In addition to these experiments, the crew took advantage of their orbit to capture stunning images of Earth. Their high-inclination orbit provided unique views of regions not typically observed during shuttle missions. The astronauts captured 6,000 images, documenting phenomena such as deforestation in the Brazilian Amazon, Hurricane Florence in the North Atlantic, the Ganges River delta, and the Sakurajima Volcano in Japan.
Retrieving CRISTA-SPAS
On November 12, the crew prepared to retrieve the CRISTA-SPAS satellite. Using a novel rendezvous technique known as the R-bar approach, Atlantis approached the satellite from below, conserving fuel and minimizing the risk of contaminating the satellite’s sensors and solar arrays. Once within 40 feet of CRISTA-SPAS, Ochoa used the RMS to grapple the satellite and secure it back in the payload bay.
Preparing for Reentry
As the mission drew to a close, the astronauts began preparations for their return to Earth. McMonagle and Brown conducted tests on Atlantis’ reaction control system thrusters and aerodynamic surfaces to ensure a smooth reentry. The crew also worked on shutting down experiments and securing equipment for the descent.
On November 14, due to Tropical Storm Gordon near the primary landing site at KSC, the crew was directed to land at Edwards Air Force Base in California. After a successful deorbit burn, Atlantis glided to a smooth landing at Edwards, marking the end of its longest flight to date, with the crew having orbited Earth 174 times.
Post-Mission Reflections
The success of STS-66 was a testament to the dedication and expertise of the crew and the mission team. Mission Scientist Timothy L. Miller lauded the mission, stating, "The mission not only met all our expectations but all our hopes and dreams as well." Commander McMonagle echoed this sentiment, emphasizing the importance of the mission’s contribution to understanding the health of our planet.
The data and observations gathered during STS-66 have provided valuable insights into Earth’s atmosphere and its interaction with solar energy, furthering our understanding of climate dynamics. As the crew returned to Houston for reunions with their families, the mission was celebrated as a milestone in space exploration.
For more insights, you can watch a narrated video by the crew about the STS-66 mission here.
For more Information, Refer to this article.
