Astro News
- Recent Updates of Astro News
- Active Mercury(07/09)
- Hubble Status Report: Directly Observes a Planet Orbiting Another Star(01/09)
- A Non-trivial Answer to a Trivial Astronomical Question-The Origin Of Absolute Magnitude(07/08)
- Assault by a Black Hole(04/08)
- New Lakes Discovered on Titan(01/08)
- ˇ§Deviant Behaviourˇ¨ in the Solar System(10/07)
- Cosmic Ripples - Cosmic Microwave Background - CMB(07/07)
- Interplanetary Superhighway(04/07)
- Is Pluto a Planet?(01/07)
- Breathing Moonrocks(10/06)
- My Thoughts on the Theory of Relativity, Quantum Mechanics, Superstring Theory and Dark Matter(07/06)
- Space-time Vortex(04/06)
- Radio Astronomy(01/06)
- Neutrino Astronomy(10/05)
- The Active Earth(07/05)
- What is Dark Energy?(04/05)
- The Mysterious Black Holes(01/05)
- Intermediate-Mass Black Holes And Quasisoft X-Ray Sources(10/04)
- Time Travel: From a Scientific Approach(07/04)
- What is Astrobiology?(04/04)
- Black Hole: From Fantasy To Reality (II)(01/04)
- Black Hole: From Fantasy To Reality (I)(10/03)
- From The Oldest Light In The Universe To The Fate Of The Universe(7/03)
- The Cosmic HERO(4/03)
- Quaoar - the Tenth Member of the Solar System?(1/03)
- The First Chinese Telescope in Space(10/02)
- Diamonds and Other Stardust(7/02)
- Supermassive Black Hole in Andromeda Galaxy(4/02)
- Detection of Solar Neutrinos(1/02)
- Simultaneous Multiple Wavwlength Observation(10/01)
- Celestial Distance(7/01)
- Solar-Terrestrial Relations(7/00)
- Fundamental Particles in Astronomy(4/00)
- The Solar Maximum in 2000(1/00)
- Hubble Constant(10/99)
- New Findings on Cosmology(7/99)
- Strange Stars(4/99)
- How Strong Stellar Magnetic Field Can Be?(1/99)



Important notices






Whenever we talk about astronomical telescope in space, we usually think of technical marvels such as the Hubble Space Telescope or the Chandra X-ray Observatory. A common thread of these facilities is that they were built and developed by the Western world. Indeed the United States and Europe have dominated the usage of our outer space as sites for studying the sky (with a few exceptions from Japan). The two major advantages of having observing facilities outside our earth's atmosphere are: first, we can get sharper images of objects without the blurring effects of our atmosphere (imagine seeing through a steamy room after you finish taking a bath). Second, we can detect radiation from stars and galaxies in frequency bands that have been blocked by the atmosphere, such as ultraviolet (UV), X-ray, and g-ray. While we need the protecting atmosphere so that we won't all be burnt by the severe UV and X-ray radiation from the sun, this also means that we will lose out on a lot of the information from the universe if we stay on the ground.

China reached a milestone with the successful deployment of the solar and cosmic high energy radiation monitoring system on the Shenzhou-II Orbiting Module early last year. The unmanned Shenzhou-II is the second in a series of about five space vehicles in preparation for sending the first Chinese astronaut to space. It was launched on January 10, 2001 at 01:00 hr (Beijing time) from the Jiuquan Satellite Launch Centre in the Gansu Province abroad a Changzheng-2F (Long March-2F) rocket. This launch is also symbolic in that it is the first rocket launch of the 21st century (don't forget that the 21st century started on the year 2001!) The Returning Module returned to earth on January 16 at 19:22 hrs (Beijing time) after orbiting the earth for 108 times. Powered by its own solar panels, the Orbiting Module remained in orbit for almost 6 months. It contains experiments to study the space environment at the orbiting altitude and, for the very first time, an orbiting astronomical telescope to study high energy radiation from objects ranging from our sun to distant cosmic explosions from far away universe.

The orbiting telescope has been developed jointly since 1993 by Nanjing University and the Laboratory of Cosmic Ray and High Energy Astrophysics of the Institute of High Energy Physics (COHEAL) in the Chinese Academy of Science. The telescope consists of three sets of detectors, sensitive to radiation from soft X-ray to g-ray, which are designed and constructed entirely in China. The telescope orbits the earth once every 92 minutes at a low-earth altitude of about 350 km. The data taken was relayed to the ground receivers at the Miyun Station near Beijing. The most scientifically productive instruments are the X-ray detectors (XD) developed by COHEAL. The detectors are in "trigger" mode in which data collection are initiated by bursts of X-ray photons. During its lifetime, the XD recorded a total of 664 triggers. The research team identified and recorded lightcurves of near one hundred solar flare events (data taken during half of the orbit when the Shenzhou-II orbiter faces the sun) and ~30 candidates of gamma ray bursts. Many of these observations were verified by similar results taken by other orbiting satellites. 

Solar flares are sudden and brief explosions that rip through our sun's atmosphere. The XD recorded the biggest solar X-ray flare on record on April 2, 2001. On the other hand, gamma ray bursts are the biggest explosions that occurred predominantly in distant universe. Their detailed origin remains unknown. That doesn't stop the astronomers from guessing though! Amongst the candidates are the collapse of supermassive stars (over 60 times the mass of the sun), mergers of two neutron stars, or conversion of a neutron star to a strange star. 

While the first astronomical observation on satellite altitude in China has generated many encouraging results, there is still plenty of room for improvement. For example, no other
astronomical instrument has been scheduled for the remaining of the Shenzhou series of missions. How wonderful it would be if the first Chinese manned space mission also carry a telescope on board! Of course, the next big step for Chinese space astronomy would be to deploy a satellite dedicated only for astronomical research. There are currently a few projects in the planning stage, including a hard X-ray all-sky survey satellite (the Hard X-ray Modulation Telescope mission), and a "microsatellite" (weight less than 100 kg) mission to study long-term variability of stars and galaxies (Space-based multi-band Variable Objects Monitor). Hopefully in 5 to 10 years time we can celebrate the launch of the first Chinese astronomical satellite.

The author would like to thank Dr Ma Yuqian, the director of the Laboratory of Cosmic Ray and High Energy Astrophysics, for thorough introduction on the XD project. 

For more information about Chinese space astronomy, check out 
http://www.ihep.ac.cn/cosmic-ray/coheal.htm
http://www.astrosv1.ihep.ac.cn/~lufj/index-hxmt.htm

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Launch of Shenzhou II on 10 January 2001

Shenzhou-II vehicle
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