What does GRO stand for?

Since the demise of the Compton Gamma Ray Observatory a decade ago, we've wondered about the nature of unidentified gamma-ray sources it detected in our galaxy.

The $690 million telescope, supported by six countries, will pick up where NASA's Compton Gamma Ray Observatory left off before its deliberate destruction in 2000, but in a bigger and better way.

In 2000, NASA engineers successfully directed a safe de-orbit of the 17-ton Compton Gamma Ray Observatory, using rockets aboard the satellite to bring it down in a remote part of the Pacific Ocean.

That chapter addresses additional topics: international cooperation; relations with the human space progra m; the gamma-ray, X-ray, optical, infrared, and radio-astronomy programs; general relativity; the Hubble Space Telescope; the Chandra X-Ray Observatory, formerly known as the Advanced X-Ray Astrophysics Facility (AXAF); the Space Infrared Telescope Facility (SIRTF); the Compton Gamma Ray Observatory (CGRO); and an extrapolation of the future.

Like the Hubble Space Telescope, Compton Gamma Ray Observatory and Chandra X-ray Observatory before it, the new telescope should also expand scientists' view of the universe in this case by piercing the dust and gas that shrouds much of space from view.

Chandra is the third in a family of powerful research satellites that includes the Hubble Space Telescope and the Compton Gamma Ray Observatory.

The object, GRO J1744-28, first was observed in December, 1995, by an Earth-orbiting satellite, the Burst and Transient Source Experiment on board the Compton Gamma Ray Observatory.

Riccardo Giacconi, Nobel Laureate and Research Professor with Johns Hopkins University, will open the day with a discussion on the many breakthrough discoveries of NASA's observatories, including the Compton Gamma Ray Observatory, Hubble and Chandra.