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| Chandra X-Ray Observatory |
| Payload Bay |
| 50,162 lbs. |
| Prime: Cady Coleman | |
| Backup: Michel Tognini | Project Scientist: Dr. Martin Weisskopf, Marshall Space Flight Center |
| Overview |
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NASA's Chandra X-Ray Observatory, the world's most powerful X-Ray telescope, is the primary payload for Space Shuttle mission STS-93. With a combination of sensitive instruments and highly X-Ray reflective mirrors, the observatory will allow scientists to study the origin, structure and evolution of our universe in greater detail than ever before. 
Airborne Support Equipment The Inertial Upper Stage and attached Chandra Observatory use airborne support equipment installed in the Shuttle to operate and deploy into space. The Airborne Support Equipment consists of mechanical, avionics and structural equipment located in the orbiter. The structural and mechanical equipment attaches the Inertial Upper Stage and the payload to the orbiter payload bay and provides the mechanisms to elevate the Inertial Upper Stage and the payload and deploy it from the Shuttle. The Airborne Support Equipment avionics provides command and information transfer between the Upper Stage and the Shuttle during payload checkout. |
| History/Background |
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Launch, Activation and Checkout The Chandra X-Ray Observatory, attached to its Inertial Upper Stage will ride into space in the Space Shuttle payload bay. Once on orbit, the Shuttle crew will activate the spacecraft power system, and controllers at the Chandra X-Ray Observatory Control Center in Cambridge, MA, will begin activating and checking out key observatory systems. Chandra controllers will activate and check out the observatory's computers, activate heaters to control the temperature of observatory systems and initiate venting of Chandra's imaging spectrometer. Controllers will also test the system that will place Chandra in a safe mode should an anomaly occur after deployment and test communications links between the observatory and the ground through Chandra's upper antenna. Approximately five-and-a-half hours after launch, the Shuttle crew will tilt the Chandra and its Inertial Upper Stage up to 29 degrees. Chandra controllers will then check radio communications links between the observatory and the ground through Chandra's lower antenna. Following initial activation and checkout of Chandra by the Operations Control Center, the Columbia crew will configure the Inertial Upper Stage for deployment, disconnect umbilicals between the orbiter and payload, and raise the payload to its deployment attitude of 58 degrees above the payload bay. 
NOTE: All Chandra event times after IUS separation are approximate. Chandra's Orbital Profile Unlike the close-to-Earth, circular orbit of the Hubble Space Telescope, the final orbit of the Chandra X-Ray Observatory will be highly elliptical. At its closest approach to Earth, the observatory will be at an altitude of about 6,200 miles. At its farthest, 87,000 miles, it will travel almost one-third of the way to the Moon. Due to this elliptical orbit, the observatory will circle the Earth every 64 hours, carrying it far outside the belts of radiation that surround our planet. This will allow for 55 hours of uninterrupted observations during each orbit. The radiation, while harmless to life on Earth, could overwhelm the observatory's sensitive instruments. To prevent interference or damage to its instruments, scientific observations will not be taken during periods of interference from Earth's radiation belts. Observatory Operations The Smithsonian Astrophysical Observatory in Cambridge, MA, will control science and flight operations of the Chandra X-Ray Observatory under contract to NASA's Marshall Center. The Smithsonian manages Chandra operations through two electronically linked facilities, known collectively as the Chandra X-Ray Observatory Center. The Operations Control Center is located in Kendall Square, and the Science Center is located at the Harvard-Smithsonian Center for Astrophysics on the campus of Harvard University. The Operations Control Center will be responsible for directing the observatory's mission as it orbits Earth. Commands for executing the observatory plan will be transmitted from the control center to one of three ground stations (in Spain, Australia, or California) that make up NASA's Deep Space Network. The Deep Space Network will relay the commands to the orbiting spacecraft. The spacecraft will carry out the commands by pointing the telescope to the specified targets, and moving the science instruments and gratings in and out of the focus area of the Chandra mirrors. During launch and on-orbit activation, the control center will be staffed around-the clock by controllers and managers from the Smithsonian, the Marshall Center, and Chandra's prime contractor, TRW. During this period, the center will remain in almost constant communication with the spacecraft. Once operational, a Smithsonian control center team will interact with the observatory three times a day by receiving science and housekeeping information from its recorders. The team also will send new instructions to the observatory as needed, as well as transmit scientific information from the X-Ray observatory to the Chandra Science Center. The science center is an important resource for scientists and the public. It will provide researchers with user support that includes science data processing and a science data archive. Other members of the support center team work with NASA and the scientific community to inform the public of discoveries made by scientists using the observatory. Scientific observations will begin approximately two months after launch. The next three to four months are set aside for Guaranteed Time Observers. They are the telescope scientist, the principal investigators of the teams that built the scientific instruments, and six interdisciplinary scientists chosen in a NASA peer review competition. Seventy percent of the remaining observing time during the first year will be reserved for General Observers. Two hundred General Observer proposals were selected from 800 submissions in a competitive peer review process. About 400 astronomical targets will be observed in the first year Program History The Chandra X-Ray Observatory - originally known as the Advanced X-Ray Astrophysics Facility - was initially envisioned as a Space Shuttle-serviceable observatory in low Earth orbit similar to NASA's Hubble Space Telescope. Necessary mirror and instrument technologies were demonstrated in the late 1980s and plans were being made for construction. In 1992 the observatory was restructured into a less costly program that eliminated on-orbit maintenance and simplified construction. July 1995 - Grinding and polishing of Chandra's mirrors completed by Raytheon Optical Systems Inc., Danbury, CT. February 1996 - Coating of the mirrors completed by Optical Coating Laboratory, Inc., Santa Rosa, CA. December 1996 - Assembly of the mirrors completed by Eastman Kodak Co., Rochester, NY. March 1997 - Mirror testing and calibration completed at NASA's Marshall Space Flight Center in Huntsville, AL. May 1997 - Science instrument testing and calibration completed at NASA's Marshall Space Flight Center in Huntsville, AL. September 1997 - Chandra Operations Control Center opens in Cambridge, MA. March 1998 - Observatory assembly completed at TRW Space and Electronics Group, Redondo Beach, CA. July 1998 - Thermal Vacuum Testing was completed at TRW. December 1998 - Observatory renamed in honor of Indian-American Nobel Laureate Dr. Subrahmanyan Chandrasekhar. Feb. 4, 1999 - Chandra shipped from TRW to the Kennedy Space Center, FL. June 2, 1999 - Chandra mated to Inertial Upper Stage at the Kennedy Space Center. June 18, 1999 - Chandra installed in transportation canister for transfer to the launch pad. |
| Benefits |
| Science Program X-Rays are an invisible form of high-energy light. They are produced in the cosmos when gas is heated to millions of degrees by violent and extreme conditions. Much of the matter in the universe is so hot that it can be observed only with X-Ray telescopes. Flaring stars, exploding stars, black holes, and galaxy clusters, the most massive objects in the universe, are among the many fascinating cosmic phenomena that Chandra X-Ray Observatory is designed to study. Images from Chandra will show up to fifty times more detail than any previous X-Ray telescope. It is a revolutionary telescope that combines the ability to make sharp images while it measures precisely the energies of X-Rays coming from cosmic sources. SUPERFLARES, SUPERNOVAE & THE BUILDING BLOCKS FOR LIFE Observations with Chandra will help scientists better understand the conditions that produce planets and life. Chandra's observations of superflares from young stars will give scientists a better idea of what conditions were like on Earth when the sun was young. Superflares are thousands of times more intense than the largest solar flare ever observed. The Earth is composed primarily of heavy elements such as carbon, nitrogen, oxygen, silicon and iron. These elements, many of which are necessary for life, are created in the interior of massive stars. Eventually, they are spread throughout space when a massive star runs out of fuel and undergoes a catastrophic explosion called a supernova. The shell of matter thrown off by the supernova creates a bubble of multimillion degree gas called a supernova remnant. This hot gas will expand and produce X-radiation for thousands of years. Chandra X-Ray Observatory images will trace the dynamics of the expanding remnant. When heavy elements present in the hot gas are heated to high temperatures, they produce X-Rays of specific energies. Chandra detectors will precisely measure the energies of these X-Rays and tell how much of each element is present. These X-Ray "color" pictures will reveal the amounts of heavy elements that have been blown off by these stars. They could verify theories for the source of the heavy elements necessary for Earth-like planets and life. BLACK HOLES & QUASARS Some of the most intense X-Ray sources in the universe are caused by super-hot gas that is swirling toward a black hole. As the tremendous gravity of a black hole pulls gas and dust particles toward it, the particles speed up and form a rapidly rotating flattened disk. Friction caused by collisions between the particles heats them and they produce X-Rays as their temperatures rise to many millions of degrees. By accurately determining the energy of individual X-Rays, the Chandra X-Ray Observatory can measure the motion of particles near the event horizon of black holes. This information will allow scientists to test theories about the gravity fields around black holes. Astrophysicists have proposed that supermassive black holes may explain the mysterious and powerful objects called quasars. These objects radiate as much energy per second as a thousand normal galaxies from a region having a diameter less than a millionth of the size of one galaxy. Because the matter closest to the event horizon of a black hole radiates most of its energy as X-Rays and gamma rays, Chandra will present an unequaled view into the inner workings of these violent cosmic whirlpools. One of the most intriguing features of supermassive black holes is that they do not suck up all the matter that falls within their sphere of influence. Some of the matter falls inexorably toward the black hole, and some explodes away from the black hole in high-energy jets that move at near the speed of light. Chandra will give new insight into the nature of these enigmatic cosmic jets. GALAXY CLUSTERS, DARK MATTER & THE UNIVERSE More than half of all galaxies in the universe are members of groups of galaxies or larger collections of galaxies, called clusters. X-Ray observations have shown that most clusters of galaxies are filled with vast clouds of multimillion degree gas. The mass of this gas is greater than all the stars in all the galaxies in a cluster of a thousand galaxies. Galaxy clusters are the largest and most massive gravitationally bound objects in the universe. Chandra images of galaxy clusters should significantly advance our understanding of the nature and evolution of the universe in a number of ways. The X-Ray producing hot gas found in a typical cluster of galaxies presents astronomers with a grand puzzle. Over time this extremely hot gas should escape the cluster since the galaxies and gas do not provide enough gravity to hold it in. Yet the gas remains in clusters of all ages. Scientists have concluded that some unobserved form of matter, called dark matter, is providing the gravity needed to hold the hot gas in the cluster. An enormous amount of dark matter is needed- about three to ten times as much matter as that observed in the gas and galaxies. This means that most of the matter in the universe may be dark matter. The dark matter could be collapsed stars, planet-like objects, black holes, or exotic subatomic particles that produce no light, and can only be detected through their gravity. Detailed measurements of the size and temperature of the hot gas clouds in galaxy clusters by Chandra X-Ray Observatory could help solve the dark matter mystery. When combined with observations from microwave telescopes, Chandra images of clusters can be used to measure the distance to the clusters. This distance measurement will give astronomers an independent measurement of the size and age of the universe to compare with measurements made with optical telescopes. Giant galaxy clusters are formed through the merger of smaller groups and clusters over billions of years. Chandra images will show shock waves produced by these awesome energetic collisions. Estimates of the epoch when clusters were formed in the universe differ greatly, depending on the theory that is adopted. If Chandra discovers massive clusters at great distances, it would challenge theories for the origin and evolution of the universe. NASA and its Partners The Chandra X-Ray Observatory program is managed by the Marshall Space Flight Center for the Office of Space Science, NASA Headquarters, Washington, DC. TRW Space and Electronics Group of Redondo Beach, CA, is the prime contractor and has assembled and tested the observatory for NASA. Using glass purchased from Schott Glaswerke, Mainz, Germany, the telescope's mirrors were built by Raytheon Optical Systems Inc., Danbury, CT. The mirrors were coated by Optical Coating Laboratory, Inc., Santa Rosa, CA, and assembled by Eastman Kodak Co., Rochester, NY. The Chandra X-Ray Observatory Charge-Coupled Device Imaging Spectrometer was developed by Pennsylvania State University, University Park, PA, and the Massachusetts Institute of Technology (MIT), Cambridge. One diffraction grating was developed by MIT, the other by the Space Research Organization Netherlands, Utrecht, Netherlands, in collaboration with the Max Planck Institute, Garching, Germany. The High Resolution Camera was built by the Smithsonian Astrophysical Observatory. Ball Aerospace & Technologies Corporation of Boulder, CO, developed the aspect camera and the Science Instrument Module. The Smithsonian Astrophysical Observatory in Cambridge, MA will control science and flight operations. Communications and data links with Chandra will be provided by NASA's Jet Propulsion Laboratory, Pasadena, CA, through the Deep Space Network. Chandra at a GlanceMission Duration
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Integral Propulsion System
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High Resolution Mirror Assembly
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Science Instruments
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Did you know?The Chandra X-Ray Observatory is the world's most powerful X-Ray telescope. It has eight times greater resolution and will be able to detect sources more than 20 times fainter than any previous X-Ray telescope. The Chandra X-Ray Observatory, with its Inertial Upper Stage and support equipment is the largest and heaviest payload ever launched by the Space Shuttle. The Chandra X-Ray Observatory's operating orbit will take it 200 times higher than the Hubble Space Telescope. Each orbit Chandra will travel one-third of the way to the moon. The Chandra X-Ray Observatory's resolving power is equal to the ability to read the letters of a stop sign at a distance of 12 miles. If the State of Colorado were as smooth as the surface of the Chandra X-Ray Observatory mirrors, Pike's Peak would be less than an inch tall. Another of NASA's incredible time machines, the Chandra X-Ray Observatory will be able to study some quasars as they were 10 billion years ago. The Chandra X-Ray Observatory will observe X-Rays from clouds of gas so vast that it takes light more than five million years to go from one side to the other. Although nothing can escape the incredible gravity of a black hole, not even light, the Chandra X-Ray Observatory will be able to study particles up to the last millisecond before they are sucked inside. |
Editorial/Technical Comments: ShuttlePresskit
