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"Not since Galileo turned his telescope toward the heavens in 1610 has any event so changed our understanding of the Universe as the deployment of the Hubble Space Telescope." – NASA

America's historic science icon is saved to explore another day...

Hubble Space Telescope is Repaired

The Beauty of Hubble »               Hubble Is Not Alone »


May 2009Hubble is repaired! Space shuttle Atlantis and a crew of seven flew up to repair the Hubble Space Telescope, orbiting 350 miles above Earth. Their departure was May 11 and their return was May 24. The shuttle mission was unique in that not only was Atlantis ready to fly, but another shuttle was on the launch pad ready to rush to the rescue in case Atlantis suffered severe launch damage that might prevent a safe re-entry. No such damage occurred so the emergency second flight was not needed. As planned, Atlantis did not travel to the International Space Station. The extra precaution was a result of shuttle Columbia being destroyed and its seven astronauts killed during re-entry in 2003. During this mission, the astronauts took five spacewalks on consecutive days that left the telescope upgraded and ready to send back even more spectacular images than before well into the next decade. The STS-125 crew left the telescope to dazzle the world for years to come, with more scientific discoveries and stunning images possible because of its improved view that stretches from our Solar System to the edge of the Universe.

The 2009 upgrades included repair and replacement on these instruments and pieces of equipment:
  • Hubble's new panchromatic camera – Wide Field Camera 3 – allows astronomers to better observe galaxy evolution, dark matter and dark energy.

  • The Cosmic Origins Spectrograph is the most sensitive spectrograph ever flown on Hubble. The new instrument peers further into the Universe than ever before in the near and far ultraviolet ranges.

  • The Advanced Camera for Surveys was repaired. It is one of Hubble's primary cameras, which had stopped working back in 2007. It has been responsible for some of the most famous images from Hubble.

  • The Space Telescope Imaging Spectrograph has been inoperable after 2004. The now repaired instrument reveals information about planets, comets, stars and galaxies.

  • The Science Instrument Command and Data Handling System had failed in September 2008 and was replaced. The new unit allows full functioning for sending information and receiving commands.

  • The Fine Guidance Sensor 2 was replaced. It is one of three sensors that help point and lock the telescope on targets.

  • The Rate Sensor Units are six new gyroscopes that work with the Fine Guidance Sensors to precisely point the telescope.

  • The Battery Module Units were replaced. They power Hubble when the solar arrays are out of the Sun's reach.

May 2008 – Space shuttle Atlantis and a crew of seven will fly up to repair the Hubble Space Telescope, orbiting 350 miles above Earth, at the end of September or early October 2008. The shuttle mission will be unique in that not only must Atlantis be ready, but another shuttle must be on the launch pad ready to rush to the rescue in case Atlantis suffers severe launch damage that might prevent a safe re-entry. Unlike other shuttle crews, which travel to the International Space Station, the astronauts on the Hubble mission would have nowhere to seek shelter in the event of a gaping hole in their ship's thermal shield. In the case of a rescue, the Hubble astronauts would put on spacesuits and float out of their ship and into the other shuttle. The extra caution is a result of shuttle Columbia being destroyed and its seven astronauts killed during re-entry in 2003 because of a hole in the shuttle's left wing caused by chunk of fuel-tank foam insulation that broke off during liftoff. Meanwhile, NASA hopes to complete construction of the space station and retire the American shuttle fleet in 2010.

November 2006 – Administrator Michael D. Griffin announced NASA will send astronauts in a space shuttle in Spring 2008 to repair the Hubble Space Telescope, which needs replacement batteries and gyroscopes to keep on working. The telescope has been stumbling along on just two of its original six gyroscopes that point and stabilize the satellite. One of its main instruments, a spectrograph, broke down in 2004. The Earth satellite's main camera stopped working for a time in Fall 2006. Of course, Hubble has been up there, working in Earth orbit since it was launched in 1990. The space shuttle fleet is to be retired in 2010 to be replaced by 2014 by a different kind of human transport known as the Crew Exploration Vehicle. After repairs in 2008, the Hubble Space Telescope should work until at least 2013 and remain in orbit until at least 2021.

June 2006 – The main camera aboard the Hubble Space Telescope – known as the Advanced Camera for Surveys – stopped working in June 2006. The camera is a third-generation instrument installed in the orbiting observatory satellite by a shuttle Columbia maintenance crew in 2002. The camera actually is three electronic cameras and a set of filters and dispersers detecting light across a range from ultraviolet to near infrared. Hubble also needs replacement batteries and gyroscopes to keep it working. Hubble was launched to Earth orbit in 1990.

April 2005 – NASA Administrator Michael D. Griffin asked engineers at Goddard Space Flight Center to begin preparations for another servicing mission to Hubble after he promised to reassess the fate of the servicing mission based on the success of the next one or two shuttle missions. Hubble servicing mission preparations would have to begin immediately to keep the possibility of a mission alive. If it were approved, a flight then could take place around mid-2007 or early 2008. Griffin replaced NASA Administrator Sean O'Keefe, who resigned in December 2004. During his confirmation hearing, Griffin had told U.S. senators he would reconsider the cancelled servicing mission to Hubble.

NASA art of Hubble orbiting above Earth and open to the cosmos

Earlier events. The Bush Administration fiscal 2006 budget proposal would have killed any attempt to save the Hubble Space Telescope (HST).

The budget sent from the White House to Congress in February 2005 proposed to spend $93 million on HST. The space agency's total budget would be $16.45 billion.

Some $75 million of the $93 million would be used to build a robot that would be sent to space to steer the orbiting observatory down into the ocean at the end of its life. The other $18 million would be used for astronomical observations before the end.

No money was proposed for sending astronauts in a space shuttle, or even a robot repair ship, to make repairs and updates so Hubble could work longer in Earth orbit. Congress debated the budget with the options of approving it or adding or subtracting money.

The proposed budget total was a 2.4 percent increase over the previous year. It included $4.5 billion for space shuttle programs.

How did we get to this point? More than three decades after the last man walked on the Moon, U.S. President George W. Bush has proposed sending humans there again, to build a permanent base, and then on to Mars.

American astronauts would return to the Moon around 2015 with a human base to be completed on the Moon soon after. Human flights to Mars would follow in the next decade.   The plan for human flights

To meet the Moon and Mars goals, the American space shuttle fleet would be retired in 2010. All shuttle flights before then would go only to the International Space Station. That would sacrifice the Hubble Space Telescope, which is not near the space station and which needs a servicing mission soon to keep on working in orbit. Without service, the big satellite's useful working life probably will be over before 2008.

Scientists Clamor to Save Hubble
As Clock Ticks for Hubble,
  Some Plead for a Reprieve
Premature Death for the Hubble
Nasa says 'no' to Hubble reprieve
'Save the Hubble' campaign soars
Hubble may get reprieve
O'Keefe to get second opinion before deciding Hubble's fate
Deserting Hubble a very bad idea
Fighting to Save Hubble Telescope From Fiery Death
Save Hubble campaign gaining momentum
Sigue el debate sobre el futuro del Telescopio Espacial
Assessment of Options for Extending the Life of the Hubble Space Telescope
Hubble's Future FAQ
Guestbook Comments
petitions to sign
Cancelled Service Mission. Hubble is a satellite in orbit about 355 miles above Earth. Space shuttles have made four servicing flights to Hubble – in 1993, 1997, 1999 and 2002.

A service mission had been planned for 2005 soon after the shuttle fleet returns to flight. The shuttle astronauts would have installed in Hubble the Cosmic Origins Spectrograph and a third-generation Wide Field Camera. Those pieces of equipment already have been built and have been awaiting launch.

Astronauts would have replaced stabilizing gyroscopes and aging batteries. Only four of the large satellite's six gyroscopes work now. At least three are needed to continue science operations. Engineers have wanted to write software that will allow the observatory to function with only two gyros, but the work is not complete.

Replacing gyroscopes and batteries would keep Hubble working until 2010. Without a servicing mission, Hubble probably will expire before 2008. The exact timeline remains to be seen.

A replacement space telescope will not be launched until 2012 or later. That could leave astronomers without their most important instrument for four years or longer.


NASA's View. The space agency says its not about money and not about the Moon-Mars initiative, but it must abandon Hubble for safety. Following the loss of Columbia in 2003, all shuttle fights now will go only to the space station because that is a safe base in the sky if a shuttle problem turns up. The space station has a lifeboat so a shuttle crew could get home safely.

A shuttle visiting Hubble would be in a faraway orbit from which it could not fly over to the space station. Thus, expensive new safety equipment would have to be developed just for missions to Hubble.

However, doing nothing is not a choice. While abandoning Hubble may resolve one problem, it brings another to the forefront.

Without servicing, Hubble's orbit will degrade and it will fall back to Earth around 2012. The satellite is so big it won't be destroyed completely by burning as it falls down through the atmosphere. The main telescope mirror and its titanium support ring probably would reach the ground.

NASA's plan had been to send up a shuttle with a propulsion module to be attached to Hubble so it could be dropped from orbit under control. Ground controllers would have kept the crashing satellite parts away from inhabited areas on our planet's surface. Now, there won't be such a shuttle mission. If a de-orbit module is to be attached to Hubble, the work may have to be carried out by an unmanned Russian robot spacecraft.

Major Protest. Stunned astronomers and outraged ordinary people around the globe raised a strong outcry after NASA's January 16, 2004, announcement. Thirteen days later, NASA Administrator Sean O'Keefe called on the chairperson of the Columbia Accident Investigation Board, Retired U.S. Navy Adm. Harold Gehman, to take another look at the decision banning space shuttle servicing of the Hubble Space Telescope.

O'Keefe indicated he hoped the review would satisfy U.S. Sen. Barbara Mikulski (D-Md.) who had demanded that NASA reconsider a Hubble servicing mission. Mikulski had told O'Keefe she had been shocked by his decision. However, O'Keefe did not reverse his order telling the Hubble team to kill the servicing mission and transfer personnel elsewhere.

Reaffirmation. In February 2004, NASA spaceflight and space science officials reaffirmed the agency's intention to abandon Hubble by not sending a shuttle to service the telescope satellite.

Possible Robot Repair?

For a year or two, there was thought of building a robot and sending it up to repair Hubble.

In April 2004, NASA Associate Administrator Ed Weiler said it might be feasible to send a robot to repair and upgrade the Hubble Space Telescope, without sending astronauts in a space shuttle. A small spacecraft might be built to fly up and attach itself to Hubble.

The major problems aboard the telescope satellite at that time included failing batteries and the gyros, which allow Hubble to point accurately.

The small robot spacecraft might plug into Hubble and feed electrical power to the observatory. That would do away with the need to remove Hubble's old batteries. The small spacecraft also might take over the pointing of Hubble as it peers across the Universe. Could the small robot also upgrade Hubble's optical instruments?

With parts of Hubble failing rapidly, such a robot mission would have to be completed before 2007 or 2008, NASA said. The space agency's contractors would have to work quickly. If the robot couldn't get there on time, Hubble might have to be shut down awaiting repairs.

Even if Hubble were not to be rescued, a small spacecraft still would have to fly up to the telescope to direct its re-entry into Earth's atmosphere. The observatory is too large for NASA to permit an uncontrolled crash on Earth.

Without a repair, it was said that Hubble's gyroscopes and batteries probably would fail by 2007.

A Second Chance? Scientists and astronomers were overjoyed in July 2004 when a high-level committee of experts recommended either a shuttle or robot repair mission for Hubble, despite NASA's expressed concern over safety.

The National Academy of Sciences panel of prominent scientists and engineers called Hubble "arguably the most important telescope in history," and urged NASA to send either an astronaut team or a robot to refurbish the space telescope.

NASA Administrator Sean O'Keefe had said on numerous occasions that a shuttle rescue mission would not be safe.

Dextre to the rescue. O'Keefe said on August 9, 2004, the space agency would plan on using a robot to fly up and repair the giant observatory satellite. Hubble is the size of a school bus.

A final go decision depended on Congress adding $1 billion for the project to NASA's budget. A decision in 2005 might have lead to a launch by 2008. At the time, it was said that the aging batteries in the telescope satellite and its steering gyroscopes would have needed to be replaced by 2008.

Dextre was the nickname given to the Canadian Space Agency's Special Purpose Dexterous Manipulator. Built to service the International Space Station, Dextre has two arms that can perform tasks like opening a panel door and replacing the batteries inside.

Engineers calculated that a Dextre robot could be blasted aloft in 3.5 years to make modifications that could extend Hubble's working life to 2013. A Dextre robot also could attach a de-orbit rocket to Hubble so the big satellite could fly down to splash in an ocean when it finally is taken out of service.

However, NASA's science-mission chief Al Diaz said on August 10, 2004, the space agency had not ruled out a human space shuttle mission to repair Hubble if the robot idea didn't pan out.

Dextre is dead. While the Canadian robot named Dextre might have been the savior of America's beloved HST, a final go decision depended on Congress adding $1 billion for the project to NASA's budget. A decision in 2005 could have led to a launch by 2008.

In March 2005, the Goddard Space Flight Center conducted a preliminary design review for a robotic mission. A robotic de-orbiting module is still in the works. Later that year, in June 2004, Administrator O'Keefe asked for proposals that would allow Hubble to be serviced by robots controlled from the ground.

However, later in 2005, the new NASA Administrator Mike Griffin said that he would like to "take the robotic mission off the plate," based on the conclusion of the Robotic Servicing Mission Design Review Committee that such a mission was not feasible because of timing and money. Dextre was dead.

The Great Observatories

NASA's Great Observatories for Space Astrophysics are a family of four orbiting satellites carrying telescopes designed to study the Universe in both visible light and non-visible forms of radiation.
  • Hubble Space Telescope was launched in 1990 as the first in the series. Hubble observes in visible light, but also has an infrared camera and a spectrometer.

  • Compton Gamma Ray Observatory, launched in 1991, was the second Great Observatory.   Compton

  • Chandra X-Ray Observatory, launched in 1999, was the third Great Observatory.   Chandra

  • Spitzer Space Telescope, formerly known as the Space Infrared Telescope Facility, launched in 2003, was the fourth Great Observatory.   Spitzer
Hubble Is Big and Fast. Hubble is similar in size to a large school bus. However, it can fit inside the cargo bay of a space shuttle.
  • As a satellite in orbit, Hubble travels around Earth at five miles per second. That's about 18,000 mph.

  • If a car could travel that fast, a road trip from New York City to Los Angeles would take 10 minutes, according to NASA.

  • It takes Hubble 97 minutes to complete one full orbit around our planet.

  • Circling Earth, Hubble travels more than 150 million miles each year.
Hubble astronomy operations are controlled by the Space Telescope Science Institute in Baltimore.

Tune-Ups in Space. To refuel and service the giant instrument, astronauts have traveled in shuttles to Hubble four times since the telescope satellite was taken to orbit in 1990. The tune-ups in space were in 1993, 1997, 1999, and 2002.
NASA's Hubble servicing missions

The satellite had been scheduled to stay in orbit above Earth, sending down pictures of the Universe, until 2010. With additional shuttle servicing missions, it would have been able to stay on the job for many years beyond 2010.

The Hubble Replacement

The James Webb Space Telescope (JWST) is being built to replace Hubble. JWST is a large, infrared space telescope satellite designed to provide even clearer pictures of our Universe than those received from Hubble.

Formerly known as the Next Generation Space Telescope (NGST), the new telescope was named for the space agency's second administrator.

The Webb Space Telescope will be aboard a satellite to be launched after 2010 to an orbit 940,000 miles out in space at the second Lagrange Point, or L2. There, the spacecraft will be balanced between the gravity of the Sun and the gravity of Earth, so a Sun shield on only one side of the satellite will be sufficient to protect the telescope from the light and heat of Sun and Earth.

While the Webb may be seen as replacing the Hubble, it will observe a somewhat different region of the electromagnetic spectrum – from the far visible to the mid-infrared. The wavelength coverage differs from that of the Hubble, which sees a range from the ultraviolet to the near-infrared. The Webb will carry a near-infrared camera, a multi-object spectrometer, and a mid-infrared spectrometer camera.

The James Webb Space Telescope is being built by Northrop Grumman Space Technology.

sto: James Webb Space Telescope

sto: 400th Anniversary of the Telescope
nasa: James Webb Space Telescope

stsci: James Webb Space Telescope

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