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STS-48: Atmosphere research satellite
With launch of the Upper Atmosphere Research Satellite from space shuttle Discovery in September 1991, a new era in studying Earth's environment from space began. The crew of STS-48 describes the mission in this post-flight film, which includes an beautiful nighttime flyover of the United States.

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STS-40: Medical lab
Astronauts, rodents and jellyfish were the subjects during extensive medical tests performed aboard the first Spacelab Life Sciences mission launched in June 1991 aboard shuttle Columbia. A space laboratory module riding in the payload bay housed the experiment facilities. The crew of STS-40 explain the mission in this post-flight film.

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Exploration update
A progress report on development of the Orion crew exploration spacecraft and the Ares launch vehicle is given during this briefing held October 18 at the Glenn Research Center in Cleveland.

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MRO early images
Some of the initial pictures and data from NASA's Mars Reconnaissance Orbiter since the craft entered its mapping orbit around the Red Planet are presented in this news briefing held October 16 from the Jet Propulsion Laboratory.

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Soyuz moves ports
The three-man Expedition 14 crew of the International Space Station complete a short trip, flying their Soyuz capsule to another docking port in preparation for receiving a resupply ship.

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STS-39: Military maneuvers
Space shuttle Discovery's STS-39 flight, launched in April 1991, served as a research mission for the U.S. Department of Defense. An instrument-laden spacecraft for the Strategic Defense Initiative Organization was released to watch Discovery perform countless rocket firings and maneuvers, as well as canisters releasing clouds of gas. The crew tells the story of the mission in this post-flight film presentation.

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STS-37: Spacewalkers help Gamma Ray Observatory
Seeking to study explosive forces across the universe, the Gamma Ray Observatory was launched aboard shuttle Atlantis in April 1991. But when the craft's communications antenna failed to unfold, spacewalking astronauts ventured outside the shuttle to save the day. The rescue EVA was followed by a planned spacewalk to test new equipment and techniques. The crew of STS-37 narrate this post-flight mission film.

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Mars rover seen by orbiter
Dazzling images from Mars are revealed by scientists. The robotic rover Opportunity has reached the massive Victoria crater with its steep cliffs and layers of rock exposing the planet's geologic history. Meanwhile, the new Mars Reconnaissance Orbiter has photographed the rover and its surroundings from high above.

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Hubble discovery
n this news conference from NASA Headquarters, scientists announce the Hubble Space Telescope's discovery of 16 extrasolar planet candidates orbiting a variety of distant stars in the central region of our Milky Way galaxy. Five of the newly found planets represent a new extreme type of planet not found in any nearby searches.

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Servicing missions are key to Hubble's longevity
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: October 27, 2006


Spacewalkers replaced Hubble's solar arrays during the 2002 servicing. Credit: NASA
 
And what a life it's been.

NASA began making preliminary plans for a large space telescope in 1973. The HST project was approved in 1977, it's 94.5-inch primary mirror was completed in 1981, the original suite of science instruments was delivered in 1983 and the telescope was completed in 1985. At that point, launch was targeted for the fall of 1986.

But the flight ultimately was delayed until 1990 because of the Jan. 28, 1986, Challenger disaster. Then, shortly after the telescope finally reached orbit in 1990, scientists were dismayed to discover the primary mirror suffered from spherical aberration.

Because of an oversight during mirror testing, the concave mirror's outer edge was too shallow by two microns - a tiny fraction of the width of a human hair. But that was more than enough to prevent light reflected from the outer regions of the mirror from focusing at the same point as light from the inner regions.

The telescope's original design specification called for 70 percent of a star's light to be concentrated in a very tiny circle. Suffering from spherical aberration, Hubble could only manage 10 percent to 15 percent. The result was blurry images.

Nothing could be done to fix the primary mirror. But engineers quickly came up with ways to reverse the blurring it causes. In a 1993 servicing mission, spacewalking astronauts installed the Wide Field Planetary Camera 2, with built-in corrective optics, and the COSTAR instrument to route corrected light to Hubble's other instruments.

Since then, the Hubble Space Telescope has become an international icon of science, one of the most productive astronomical observatories ever built and the flagship of NASA's exploration of the universe.

The remotely-controlled spacecraft has helped astronomers confirm the existence of black holes, zero in on the true age of the universe and spot the faint glimmer of stars in galaxies born within a billion years or so of the big bang birth of the cosmos.

Its spectacular photographs have charted the life cycles of distant suns in enormous detail, providing unmatched views of stellar nurseries and the explosive end results of stellar evolution.

It has catalogued myriad infant solar systems in the process of forming planets and provided flyby-class views of the outer planets in Earth's own solar system, routinely capturing phenomena as common as dust storms on Mars to the once-in-a-lifetime crash of a comet into giant Jupiter.

More recently, Hubble has shed light on the evolution and ultimate fate of the universe, measuring the light of ancient supernovas to help confirm the expansion of the universe is accelerating, not slowing down as previously thought.

There are more than 40 ground-based telescopes with bigger mirrors than Hubble's relatively modest 94.5-inch primary and more are on the way. But the space telescope remains in a class by itself, thanks to its location high above Earth's turbulent, obscuring atmosphere and periodic shuttle servicing to upgrade its instruments.

"The thing to remember about these Hubble servicing missions is they're not just let's keep a groaning patient on life support," said Bruce Margon, then associate director for science at the Space Telescope Science Institute in Baltimore. "When you put new focal plane instruments into Hubble, you essentially leave with not only a brand new, but a much better observatory. And when you look at our graph of discoveries as reflected by published scientific papers versus year, it's an amazing thing because it just goes up every single year. In the 15 years since launch, ever year has resulted in more refereed discovery papers than the previous year.

"The reason for that is not that the scientists who are using Hubble are smarter, it's servicing. That's the reason, because when you leave Hubble you have not just something with better longevity but something that is an order of magnitude more capable than the previous thing, almost like it's a brand new generation of satellite. And the two new focal plane instruments for SM-4 are predicted to do the same thing. And it's not a whistling in the wind prediction."

Along with installing COSTAR and WFPC-2 during Servicing Mission 1 in 1993, shuttle astronauts also installed two new solar arrays, solar array drive electronics, magnetometers, a coprocessor to boost the speed of Hubble's flight computer, two rate sensor units and two gyroscope electronic units.

Servicing Mission 2, launched in 1997, provided two new instruments - the Space Telescope Imaging Spectrograph and the Near Infrared Camera and Multi-Object Spectrometer - along with a refurbished fine guidance sensor, upgraded electronics, a solid-state data recorder, a reaction wheel assembly, solar array drive electronics and a data interface unit.

Because of gyro failures, Servicing Mission 3 was broken up into two flights, SM-3A and SM-3B. During SM-3A in 1999, shuttle astronauts installed six new gyroscopes, six battery voltage/temperature kits, a faster flight computer, another solid-state data recorder, a new radio transmitter, an upgraded fine guidance sensor and insulation.

NASA's fourth servicing mission, SM-3B, was launched in March 2002. During that flight, astronauts installed the Advanced Camera for Surveys, two new solar arrays, a power control unit, and an innovative "cryocooler," a sophisticated device that restored NICMOS to operation after its internal coolant was exhausted.

SM-4 would be NASA's final Hubble servicing mission. The latest internal flight plan shows heat shield inspections the day after launch followed by capture of Hubble the next day. The day after that, the astronauts would carry out the first of five back-to-back spacewalks:

  • EVA-1: Installation of three rate sensing units (six gyros) and one battery module (three batteries)

  • EVA-2: Installation of the Cosmic Origins Spectrograph and the second battery module

  • EVA-3: Installation of the Wide Field Camera 3 and insulation repairs

  • EVA-4: Space Telescope Imaging Spectrograph repair and aft shroud cooling system work

  • EVA-5: Installation of Fine Guidance Sensor No. 3 and associated equipment.

"All of the tasks kind of break down into two big categories," SM-4 mission director Chuck Shaw said in an interview last year. "The life extension tasks and then the mission science extension tasks. And the life extension tasks are clearly the most important, to keep the facility operating, and we'll get those done and then the mission science extension tasks, where we install new capability to do science above what it can do now."

Continue to Part 4 -->