Advanced Satellite for Cosmology & Astrophysics (ASCA, formally Astro-D)

Study in space exploration collaboration between nations heading into the unknown 

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ASCA (ASTRO-D) scientific results included the first imaging of X-ray objects by the scintillation proportional counter on March 17, 1993, and observation of X-rays from the supernova SN1993J recently discovered in the M81 galaxy. Credits: Japanese Aerospace Exploration Agency (JAXA)

Space news (astrophysics & cosmology: x-ray astronomy; spectral resolution of supernovae, accreting binaries, active galactic nuclei, and galaxy clusters) – between 525 – 615 kilometers above the Earth, orbiting every 96 minutes while observing the x-ray universe –  

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This diagram shows the configuration and overall shape of ASCA. Credits: JAXA

Japan’s 4th cosmic x-ray space mission and the second collaboration between NASA and ISAS to launch into orbit around the Earth, the Advanced Satellite for Cosmology & Astrophysics (ASCA) opened a new window on the x-ray universe. Designed and engineered to conduct x-ray spectroscopy ASCA (formally Astro-D) paved a path for NASA’s Chandra X-ray Observatory, XMM-Newton and Japan’s Suzaku (Astro-EII) to study x-ray emissions across the night sky. This smaller eye on the x-ray universe was the perfect complement to ROSAT’s all-sky survey of around 150,000 x-ray sources and RXTE’s study of the different types observed. Making this little satellite an essential, pivotal mile marker during the human journey to the beginning of space and time. Combined, these space missions have an advanced human understanding of the high-energy universe and revealed mysteries keeping astronomers up at night and peering into the unknown x-ray universe at the cosmos beyond human imagination. 

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After the success of HAKUCHO, Japan launched an X-ray astronomy satellite every four or five years: HINOTORI (solar X-ray) in 1981, TENMA in 1983, GINGA in 1987, and ASCA in 1993. Credits: JAXA.

ASCA (Astro-D) launched from Japan’s Kagoshima Space Center at the southern tip of Japan on Kyushu island on February 20, 1993, aboard ISAS’s fourth generation Mu launch system M-3sII. Orbiting at a distance from Earth at perigee of 525 and 615 at apogee, it took only 96 minutes on average for Astro-D to complete one revolution of its nearly circular path around the planet. During a lifespan lasting nearly 8 years, Japan’s little x-ray satellite provided the first images of x-ray emitting objects and detected x-rays from supernova SN 1993J in galaxy M81. The data it supplied allowed astronomers to reveal clues to the origin and formation of accreting binaries, the accretion disks of active galactic nuclei, galaxy clusters, and supernovae. 

Using combined data from a trio of orbiting X-ray telescopes, including NASA’s Chandra X-ray Observatory and the Japan-led Suzaku satellite, astronomers have obtained a rare glimpse of the powerful phenomena that accompany a still-forming star. A new study based on these observations indicates that intense magnetic fields drive torrents of gas into the stellar surface, where they heat large areas to millions of degrees. X-rays emitted by these hot spots betray the newborn star’s rapid rotation. Credits: JAXA/NASA.
Using combined data from a trio of orbiting X-ray telescopes, including NASA’s Chandra X-ray Observatory and the Japan-led Suzaku satellite (ASCA), astronomers have obtained a rare glimpse of the powerful phenomena that accompany a still-forming star. A new study based on these observations indicates that intense magnetic fields drive torrents of gas into the stellar surface, where they heat large areas to millions of degrees. X-rays emitted by these hot spots betray the newborn star’s rapid rotation. Credits: JAXA/NASA.

A tough little satellite says goodbye

This tough little satellite operated until July of 2000 when fluctuations in solar activity caused Earth’s atmosphere to expand. ASCA experienced friction caused by the thinner atmosphere and fell into an uncontrolled spin. Minimal satellite operations continued until around 14:20 on March 2, 2001, when Astro-D fell deeper into the planet’s gravity well and disappeared. Bringing to a close a chapter in space history on a little satellite that opened a window to the x-ray universe and revealed clues to a weird, weird, weird cosmos beyond human imagination. 

Follow the space journey of NASA

Learn more about the space discoveries of ISAS here

Learn more about the things ASCA told us about the origins and formation of galaxy clusters

Read about the things Astro-D told us about the accretion disks of active galactic nuclei here

Discover what Astro-D discovered about accreting binaries

Read about what x-ray emissions ASCA detected from supernova SN 1006 told astronomers about its origins and formation

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