Chandra Booklet

Chandra X-Ray Observatory What is Chandra? Chandra is the third of NASA’s Great Observatories along with the Compton Gamma Ray Observatory and Hubble Space Telescope. It is the largest and most sophisticated X-ray observatory ever constructed. After it is launched into orbit around Earth, Chandra will be able to detect X-ray sources that are billions of light years away and produce images twenty-five times sharper than the best previous X-ray telescope. Chandra’s focusing power is equivalent to the ability to read the headline of a newspaper at a distance of half a mile! Mission Specifications Size: 45.3 ft x 64.0 ft Antennas: two low-gain, conical log (solar arrays deployed) spiral antennas Weight: 10,560 pounds Frequencies: transmit 2250 MHz, receive 2071.8 MHz Orbit: 6,200 x 86,000 miles Command Link: 2 kilobits per second (kbps) 28.5 deg. inclination Ascending node: 200 degrees Data Recording: solid state recorder; 1.8 gigabits (16.8 hrs) recording capability Argument of perigee: 270 degrees Downlink: downloaded typically every Operations: eight hours Life: minimum 5 years Contingency Mode: 23 kbps Power: two 3-panel silicon solar arrays (2350W) Safing: autonomous operation three 40 amp-hour nickel hydrogen batteries The Chandra Launch - STS 93 Astronaut Crew The Chandra Observatory will be carried into orbit by the Space Shuttle Columbia, on shuttle mission STS 93. The space shuttle commander for this mission will be Col. Eileen Collins, USAF, NASA. Colonel Collins will be the first woman to command a space shuttle mission. The shuttle pilot will be Cmdr. Jeff Ashby, USN, NASA. Dr. Steven Hawley, NASA, Dr. Cady Coleman, Maj. USAF, NASA, and Col. Michel Tognini, of the French Air Force and French Space Agency, will be the mission specialists in charge of carrying out the scientific objectives of the mission. Eileen Collins was born in Elmira, New York. She is married to Pat Youngs. They have one child. She enjoys running, golf, hiking, camping, reading, photography, and astronomy. She graduated from Elmira Free Academy, Elmira, New York, and received degrees from Corning Community College and Syracuse University and a master of arts degree in space systems management from Webster University. Before becoming an astronaut, Col. Collins was an instructor pilot at the Air Force Academy in Colorado. She has logged over 5,000 hours in 30 different types of aircraft, over 400 hours in space. In 1995 she became the first woman to pilot the space shuttle. Jeffrey S. Ashby was born in Dallas, Texas and raised in the Colorado mountains. In his spare time he likes to ski, backpack and go fly-fishing. Major Ashby graduated from Evergreen High School, Evergreen, Colorado, received a bachelor of science degree in mechanical engineering from the University of Idaho and a master of science degree in aviation systems from the University of Tennessee. He is a Top Gun aviator and test pilot with over 6000 flight hours, 1000 carrier landings, and 33 combat missions during Operation Desert Storm. This will be his first flight into space. Steven A. Hawley was born in Ottawa, Kansas and grew up in Salina, Kansas. He is married to the former Eileen Keegan. He enjoys basketball, softball, golf, running, playing bridge, and umpiring. Hawley graduated from Salina (Central) High School; received a bachelor’s degree in physics and astronomy from the University of Kansas and a Ph.D. in astronomy and astrophysics from the University of California in 1977. This will be Dr. Hawley’s fifth flight on a space shuttle mission. Altogether, he has logged 650 hours in space. Catherine G. “Cady” Coleman was born in Charleston, South Carolina. Married, she enjoys flying, scuba diving, sports, and music. She graduated from W.T. Woodson High School, in Fairfax, Virginia, received a bachelor of science degree in chemistry from the Massachusetts Institute of Technology, and a Ph.D. in polymer science and engineering from the University of Massachusetts. Dr. Coleman, who is also a Major in the U.S. Air Force, was a mission specialist on a previous space shuttle Columbia flight, in 1995. Michel Tognini was born in Vincennes, France. He is married to the former Elena Vassilievna. They have four children. Hobbies include Aeroclub, parachuting and parenting, tennis, wind-surfing, water-skiing, snow-skiing, cross-country running, wave-surfing and microcomputers. Col. Tognini was educated at Lycee de Cachan, Paris. He received an advanced mathematics degree from Epa Grenoble, and an engineering degree from Ecole de l’Air (the French Air Force Academy). He is an experienced test pilot and made his first space flight on board the Soyuz spacecraft. CHANDRA The Man Behind The Name NASA’s premier X-ray observatory was named the Chandra X-ray Observatory in honor of the late Indian-American Nobel laureate, Subrahmanyan Chandrasekhar. Known to the world as Chandra (which means “moon” or “luminous” in Sanskrit), he was widely regarded as one of the foremost astrophysicists of the twentieth century. Chandra immigrated in 1937 from India to the United States, where he joined the faculty of the University of Chicago, a position he remained at until his death. He and his wife became American citizens in 1953. Trained as a physicist at Presidency College, in Madras, India and at the University of Cambridge, in England, he was one of the first scientists to combine the disciplines of physics and astronomy. Early in his career he demonstrated that there is an upper limit - now called the Chandrasekhar limit - to the mass of a white dwarf star. A white dwarf is the last stage in the evolution of a star such as the sun. When the nuclear energy source in the center of a star such as the sun is exhausted, it collapses to form a white dwarf. This discovery is basic to much of modern astrophysics, since it shows that stars much more massive than the sun must either explode or form black holes. Chandra was a popular teacher who guided over fifty students to their Ph.D’s. His research explored nearly all branches of theoretical astrophysics and he published ten books, each covering a different topic, including one on the relationship between art and science. For 19 years, he served as editor of the Astrophysical Journal and turned it into a world-class publication. In 1983, Chandra was awarded the Nobel prize for his theoretical studies of the physical processes important to the structure and evolution of stars. According to Nobel laureate Hans Bethe, “Chandra was a first-rate astrophysicist and a beautiful and warm human being. I am happy to have known him.” “Chandra probably thought longer and deeper about our universe than anyone since Einstein,” said Martin Rees, Great Britain’s Astronomer Royal Chandra X-Ray Observatory Why does Chandra have to be in space? Earth’s atmosphere absorbs X-rays coming from very hot cosmic matter. Even if Chandra were on a moun taintop like most optical telescopes, no cosmic X-rays could be detected. What is unusual about Chandra’s orbit? Chandra will not be in low- Earth orbit like the Hubble Space Telescope. After launch, a built in propulsion system will boost Chandra into a large elliptical orbit around Earth. In this orbit, the distance of Chandra from Earth will range from 10,000km (6,200 miles) to more than a third of the way to the moon. The time to complete an orbit will be 64 hours and 18 min utes. This allows for observation times as long as 52 hours, much longer than can be achieved with the low-Earth orbit of a few hundred kilometers used by most satellites. When Chandra is in orbit, how will the observatory be operated? The Observatory will be operated by the Chandra X-Ray Observatory Center (CXC) located in Cambridge, Massachusetts, at the Smithsonian Astrophysical Observatory (SAO), and staffed by personnel from SAO, MIT, and TRW. The CXC is responsible for mission planning and science operations. The CXC’s Operations Control Center will be responsible for controlling the flight operations of the observatory, for executing the observing plan, and for receiving the data that Chandra sends back. How many days is 52 hours? What would happen if you left ordinary camera film exposed for this long? What does this tell you about the brightness of distant cosmic X-rays sources? What other types of radiation (besides X-rays) does our atmosphere block out? What types ? of radiation does it let through? The X-ray Universe What is the X-ray Universe? Light produced by matter in space comes in many forms: radio waves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. The starlight our eyes can see in the night sky is visible light. The X-ray universe refers to the universe as observed with telescopes designed to detect X-rays. We could equally well speak of the radio universe or the visible universe. These are not separate universes they are just different ways of observing the same universe. Why observe the cosmos with different types of telescopes? Many objects cannot be seen by even the most powerful optical telescopes which detect radiation in the form of visible light. Radio and infrared telescopes can observe cool clouds of gas and dust that are invisible to optical telescopes. X-ray telescopes observe extremely hot matter with temperatures of millions of degrees Celsius. Without different types of telescopes, we would miss important discoveries about the universe. Does an X-ray telescope take X-rays of the cosmos? No, X-ray telescopes do not work like X-ray machines.

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