reblog from Jaxa
Extract from an interview with Yasuo Nakamura (JAXA, Japan Aerospace Exploration Agency) project manager of Wideband InterNetworking engineering test and Demonstration Satellite (WINDS).
Q. What are the major features of
WINDS?
WINDS' primary features are ultra-high-speed Internet communication capability and wide coverage. High-speed communication can be achieved with smaller-than-conventional user terminals. The WINDS communication system is designed for a maximum down link rate of 155 Mbps with a 45-centimeter aperture antenna for home use, which is faster than commercial optical fiber, and ultra-high-speed 1.2 Gbps data communications with a five-meter antenna for business users. WINDS is a geostationary satellite stationed above Japan at an altitude of 36,000 km, and can cover one third of the globe. Another notable feature of WINDS is its onboard Asynchronous Transfer Mode (ATM) switch, developed by NICT. The device will rapidly sort uplink signals by destination address and beam downlink signals directly to the correct addresses. In conventional satellite-based communications, signals received by satellite have to be transmitted to the ground for sorting of destination addresses and then resent to the satellite for distribution. With WINDS's onboard switch, communication delay will be reduced and resource utilization of the satellite will be improved. WINDS's ATM is the fastest among all satellite-based ATMs. Satellite-based communications are essentially robust against disaster. Even if communication networks are disrupted and electricity lines are down, an Internet connection can be easily set up anywhere, with a 45-centimeter-antenna user terminal. WINDS will be able to link up with communication networks on the ground and promptly deliver disaster information. Given these advantages, the purpose of WINDS is to develop and demonstrate technology to establish the world's most advanced information society. After launch, we will verify and demonstrate the new technology through engineering and application experiments. WINDS will help establish reliable advanced Internet communications, and build a truly interconnected society.
Q. What kind of communication devices will
WINDS be equipped with?
WINDS uses Ka-band frequency radio waves, which have a frequency range of about 20 to 30 GHz. These high-frequency radio waves are suitable for large-capacity communications, but their power is diminished by rain, which means that communications quality is degraded in rainy areas. Although the quality can be improved by boosting the radio-wave power, this requires a lot of electricity. And since electricity for a satellite is generated by solar array paddles, it is a limited resource. It was a critical challenge to find the most efficient means of allocating this limited power supply. In the end, we equipped WINDS with a Multi-Port Amplifier (MPA) that can flexibly assign transmission beams as needed: it will allocate power efficiently by sending a stronger signal to a rainy region, and a weaker signal to a sunny region. WINDS also has two Multi Beam Antennas (MBAs) with fixed radio-wave directions to be combined with the MPA. One antenna covers Japan using nine fixed beams; the other covers ten other Asian cities, including Manila, Bangkok and Singapore. Another onboard device is an Active Phased Array Antenna (APAA) for establishing ultra-high-speed communications in wide areas. The APAA can change the beam direction flexibly and rapidly. With this ability, the APAA will enable Internet communications in regions that the multi-beam antennas cannot cover. By instantly shifting a beam within the sightline of WINDS in its geostationary orbit, from Hawaii to Oceania for example, the APAA is capable of providing Internet communications to about one third of the Earth. WINDS communication systems using Ka-band frequency are cutting-edge technology.
Q. How will WINDS benefit our daily life?
Although the Internet is very popular in urban areas, connectivity is not yet sufficient in many mountainous regions, on remote islands, or in Asian countries where the communications infrastructure is not well developed. WINDS can make advanced high-speed communications available even in such areas. Today, the reach of the Internet is spreading rapidly, and its potential is expanding dramatically, changing the way we live our lives. In the future, certain administrative procedures, education, and even certain aspects of medical care will happen over the Internet. I think that high-speed Internet services will establish new infrastructure for our daily lives, creating an environment that even the elderly, who are not accustomed to using computers, will find convenient and reliable. WINDS technology will also contribute to disaster management. In Asian countries, where natural disasters happen frequently, it is important to acquire disaster information promptly, in order to provide the best response. With WINDS, we'll be able to link up quickly with small, portable ground stations in the disaster region, and even send high-definition images right away to disaster management headquarters and news organizations. We'd like to see WINDS technology provide a bridge between disaster zones, disaster management headquarters and the public, even if conventional communication networks are disrupted.
Q. What is the WINDS operation schedule after launch?
After the satellite is launched by H-IIA rocket in the winter of the fiscal year 2007, we'll perform its initial check of the satellite and network. Then, JAXA and NICT will conduct basic experiments to verify and demonstrate the function and performance of communication networks between the satellite and the ground. Also, the Ministry of Internal Affairs and Communications has chosen 53 experiments to be carried out with WINDS, from applications submitted by domestic and overseas research institutions, universities and the private sector. These include experiments related to communications technology, disaster management and education. For instance, we're going to conduct experiments in Internet distance education, also known as “e-learning,” between universities in Japan and other Asian countries. Distance education has traditionally consisted of one-way communication from teacher to students, or one-to-one interaction. However, the Asynchronous Transfer Mode switch, which I described previously, will facilitate more interactive communication among students and teacher. For instance, students in Japan and Thailand will be able to talk directly to each other via WINDS, allowing everyone in the class to get involved. We'd like to explore the entire potential of WINDS as we ensure the success of all these experiments.
Q. Could you tell us about international cooperation around WINDS?
Many Asian countries are participating in the experiments selected by the ministry. Among them, experiments in satellite disaster management are a major focus. The Sentinel Asia project, which aims to share disaster-related information on the Internet, is primarily led by JAXA for disaster management in the Asia-Pacific region. Satellite images taken by the Advanced Land Observing Satellite, ALOS, have already been used; in the next step, communications satellites will play an important role in data distribution. We are currently looking for ways to maximize the utility of WINDS in disaster management. Eventually, I strongly hope to make great contributions to the international community with the satellite.
Q. What is your greatest expectation for WINDS?
As Internet technology has advanced, online content has rapidly evolved from text only to audio and video, encouraging people to share various types of information more and more. Life with the Internet is becoming the norm. Having said that, people in remote areas do not have sufficient access to the Internet infrastructure that's taken for granted in urban areas. If society is established around the Internet, certain regions will benefit, while others could be left behind. Social-network systems should not exclude whole groups of people, and there should be no digital divide based on geography. WINDS technology, which allows high-speed communications to be accessed from anywhere, could solve this problem. I hope that WINDS will become a means to making the world a better place. Also, in the case of a disaster, communication technology plays a critical role in obtaining accurate data and delivering information to people in the afflicted area. People feel much more secure when they know that communication networks won't be interrupted. It is comforting to know that, no matter what, information can be delivered to you, and your information can reach the other end. I hope that WINDS technology will contribute to building a society with such security.
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Yasuo Nakamura, Project Manager, Wideband InterNetworking engineering test and Demonstration Satellite (WINDS) Mr. Nakamura joined NASDA, the National Space Development Agency of Japan (now JAXA), in 1974, and was involved in environmental testing and development of thermal control systems for spacecraft. After working on the Advanced Earth Observing Satellite Midori (ADEOS), working as a director of NASDA's Paris Office, and further work on the Advanced Earth Observing Satellite Midori II (ADEOS II), he was appointed to his current position in 2003.