Solar Physics Satellite "HINODE" (SOLAR-B) Mission talk by team leaders

All living things including human beings can not exist without the Sun. The true profile of this most familiar planet to us is surprisingly unknown. A layer of ultra high temperatures of over 1 million degrees Celsius, known as the corona, spreads around the Sun, but how can the corona stay at such high temperatures above 6,000 degrees Celsius on the solar surface? How does the massive emission of X-rays and gases (known as flares and coronal mass ejections) occur abruptly in the corona and why does it happen at such a high speed? There are so many hidden things we don’t know about the Sun.

The "Hinode" (SOLAR-B) satellite was launched in September 2006 as a successor of the "Yohkoh" (SOLAR-A) satellite, which found the corona is filled with unexpectedly dynamic activities. The "Hinode" is investigating the mystery of solar activities and the corona. Inside the corona, many lines of magnetic forces stretch out all in various directions from pairs of North and South magnetic poles (the same as the North and South magnetic poles of a magnet) that show their faces at various points on the solar surface. These magnetic lines and the high-temperature corona atmosphere assumingly generate the coronal activities. The "Hinode" carries three advanced telescopes: the Solar Optical Telescope (SOT), the X-ray Telescope (XRT) and the EUV Imaging Spectrometer (EIS). This is a mission to try and solve the mysteries of the Sun through precisely and simultaneously observing the magnetic activities on the Sun’s surface and corresponding coronal activities.

Project manager

Taro Sakao

As the activities on the Sun take place in the same time scale as our daily lives, it becomes important to continuously make observations without any omissions. The "Hinode" flies around the so-called Sun-synchronous polar orbit, flying above the North and South poles of the Earth and the border of day and night. By taking this orbit, the "Hinode" can monitor the Sun consecutively 9 months out of a year without going into the shade of the Earth and exhibits its power of observation through the accumulation of magnetic energy on the Sun's surface or in the corona, which becomes a source of dynamic solar activities.

The "Hinode" was developed as an extensive international project, with cooperation from the National Astronomical Observatory of Japan, domestic research organizations and manufacturers, NASA in the United States and the Science and Technology Facilities Council (STFC) of the U.K. After the launch, the European Space Agency (ESA) joined the project to provide ground data reception. The acquired data is uploaded on various web sites including of the Institute of Space and Astronautical Science (ISAS) of JAXA and researchers (and the general public) from around the world have access to the data.

Since the "Hinode" started its observations, it has brought various discoveries to us, and has created new mysteries. It has also had a huge impact on the field of solar physics. In addition, activities linked to related fields like plasma physics and heliospheric research are making rapid progress. On the other hand, solar activities spread X-rays and gases into the solar system and a part of them rush to the Earth, sometimes leading to satellite malfunctions in orbit. As satellites have become indispensable for our daily lives for weather forecasting, communications and using the GPS, solar activities have a much closer relationship to us. As the "Hinode" tries to detect origin, process and consequence of solar activity phenomena, a great deal of anticipation awaits for Hinode's contribution on "space weather forecasting" to predict the space environment around Earth.

I hope the "Hinode" can enrich our perceptions on the nature by unveiling its new aspects that we haven't even imagined before, together with physical processes taking place behind them. Please stay tuned on "Hinode."

(July 28, 2008 Updated.)