NASA's Hubble Space Telescope crossed another milestone¹ in its space odyssey²（冒险旅程） of exploration and discovery. On Monday, July 4, the Earth-orbiting observatory³ logged its one millionth science observation during a search for water in an exoplanet's atmosphere 1,000 light-years away. "For 21 years Hubble has been the premier⁴（第一的） space science observatory, astounding⁵ us with deeply beautiful imagery and enabling ground-breaking science across a wide spectrum⁶ of astronomical⁷ disciplines," said NASA Administrator⁸ Charles Bolden. He piloted the space shuttle mission that carried Hubble to orbit. "The fact that Hubble met this milestone while studying a faraway planet is a remarkable⁹ reminder¹⁰ of its strength and legacy¹¹."

Although Hubble is best known for its stunning¹² imagery of the cosmos¹³, the millionth observation is a spectroscopic measurement, where light is divided into its component¹⁴ colors. These color patterns can reveal the chemical composition of cosmic sources.

Hubble's millionth exposure is of the planet HAT-P-7b, a gas giant planet larger than Jupiter orbiting a star hotter than our sun. HAT-P-7b, also known as Kepler 2b, has been studied by NASA's planet-hunting Kepler observatory after it was discovered by ground-based observations. Hubble now is being used to analyze¹⁵ the chemical composition of the planet's atmosphere.

We are looking for the spectral¹⁶ signature of water vapor¹⁷（水蒸汽） . This is an extremely precise observation and it will take months of analysis before we have an answer," said Drake Deming of the University of Maryland and NASA's Goddard Space Flight Center in Greenbelt, Md. "Hubble demonstrated it is ideally suited for characterizing the atmospheres of exoplanets, and we are excited to see what this latest targeted world will reveal."

Hubble was launched April 24, 1990, aboard space shuttle's Discovery's STS-31 mission. Its discoveries revolutionized nearly all areas of astronomical research from planetary science to cosmology. The observatory has collected more than 50 terabytes of data to-date. The archive of that data is available to scientists and the public at: http://hla.stsci.edu/

Hubble's odometer（里程表） reading includes every observation of astronomical targets since its launch and observations used to calibrate¹⁹ its suite¹⁸ of instruments. Hubble made the millionth observation using its Wide Field Camera 3, a visible and infrared²⁰ light imager with an on-board spectrometer. It was installed by astronauts during the Hubble Servicing Mission 4 in May 2009.

"The Hubble keeps amazing us with groundbreaking science," said Sen. Barbara A. Mikulski, the chairwoman of the Senate Commerce, Justice, Science and Related Agencies Appropriations²¹ Subcommittee that funds NASA. "I championed the mission to repair and renew Hubble not just to get one million science observations, but also to inspire millions of children across the planet to become our next generation of stargazers（占星师，天文学家） , scientists, astronauts and engineers."