Akebono

JAXA's Akebono satellite, also known as the EXOS-D, was the first Japanese scientific satellite dedicated to studying the Earth's magnetosphere. It was launched on February 22, 1989, from the Kagoshima Space Center in Japan, and was operational until its reentry on April 1, 2015. In this essay, we will explore the history, purpose, design, launch, cost, and achievements of the Akebono satellite.

History and Purpose

In the early 1980s, Japan began to establish a national space development policy to advance its space technology capabilities. The policy's goal was to contribute to international scientific research, improve domestic technology, and promote economic growth. In 1982, the Institute of Space and Astronautical Science (ISAS), which is now a part of JAXA, was tasked with developing a scientific satellite to study the Earth's magnetosphere.

The Earth's magnetosphere is the region around the Earth where the planet's magnetic field dominates the behavior of charged particles. The magnetosphere plays a crucial role in protecting the Earth from the solar wind and cosmic radiation. However, the behavior of the magnetosphere is still not fully understood. The Akebono satellite's mission was to study the Earth's magnetosphere and its interaction with the solar wind to improve our understanding of the magnetosphere and its impact on Earth.

Design and Development

The Akebono satellite was designed and developed by the ISAS in collaboration with the National Space Development Agency of Japan (NASDA), which is now a part of JAXA. The satellite was cylindrical in shape, measuring 2.2 meters in diameter and 2.9 meters in height, and weighed 391 kg. The satellite was equipped with a variety of instruments to measure and analyze the magnetosphere's properties and behavior.

The Akebono satellite's primary instrument was the Plasma Wave Analyzer (PWA), which was designed to measure the electric and magnetic fields of plasma waves in the magnetosphere. The satellite was also equipped with a Fluxgate Magnetometer (FGM) to measure the magnetic field's direction and strength and a SupraThermal Ion Mass Spectrometer (STICS) to measure the composition and energy distribution of ions in the magnetosphere. The Akebono satellite also carried a variety of other instruments, including a Particle Detector (PD), a Low-Energy Ion Mass Spectrometer (LEIMS), and an Energetic Particle Analyzer (EPA).

Launch and Cost

The Akebono satellite was launched on February 22, 1989, from the Kagoshima Space Center in Japan. The satellite was launched on a Delta rocket provided by the United States. The launch was successful, and the Akebono satellite was placed into a highly elliptical orbit around the Earth, with an apogee of 36,000 km and a perigee of 300 km.

The total cost of the Akebono satellite program is not publicly available. However, it is estimated that the satellite's development and launch cost around 40 billion yen (approximately $364 million USD). The Akebono satellite's operations and maintenance costs were covered by the Japanese government and JAXA.

Achievements

The Akebono satellite was a groundbreaking mission that significantly advanced our understanding of the Earth's magnetosphere. The satellite's measurements and analyses provided important insights into the behavior of the magnetosphere and its interaction with the solar wind. Some of the Akebono satellite's most significant achievements include:

Discovering the plasma sheet boundary layer: The Akebono satellite discovered the plasma sheet boundary layer, a region where the Earth's magnetic field lines cross and plasma from the magnetosphere mixes with plasma from the solar wind. This discovery provided critical information about the structure and behavior of the magnetosphere.

Studying substorms: Akebono provided the first detailed measurements of substorms, which are disturbances in the magnetosphere that can cause auroras and disrupt satellite communications. The satellite's measurements allowed scientists to develop a better understanding of the causes and effects of substorms.

Observing magnetic reconnection: Akebono was the first satellite to observe magnetic reconnection, a process in which magnetic field lines break and reconnect, releasing energy and accelerating particles. This process is thought to be responsible for many of the phenomena observed in the magnetosphere.

Contributing to international research: The Akebono satellite collaborated with other satellites and ground-based instruments to provide a more comprehensive understanding of the magnetosphere. Akebono's data were used in numerous scientific publications and contributed to international research efforts.

Conclusion

The Akebono satellite was a pioneering mission that significantly advanced our understanding of the Earth's magnetosphere. The satellite's measurements and analyses provided important insights into the behavior of the magnetosphere and its interaction with the solar wind. The Akebono satellite's achievements paved the way for future missions to study the Earth's magnetosphere, and its legacy continues to inform scientific research to this day.