Q. Could you give us an outline of the small scientific satellite project?
Common structure to meet various mission needs
We develop small scientific satellites weighing 500 kilograms or less, to complement conventional large and mid-size satellites. Recent advancements in technology have made it possible to downsize instruments, and we think that small satellites can be used in many research projects that would have required much larger satellites in the past. Having said that, the capabilities of small satellites are still limited - they cannot completely match large satellites, which can weigh several tonnes and are equipped with multiple scientific instruments. So we will pursue narrow and specialized mission objectives, in order to make cutting-edge achievements in specific fields. In addition, we are working to cut costs by shortening development time, and to be flexible enough to meet the needs of many different kinds of scientific satellite missions. Q. What is the advantage of small scientific satellites compared to conventional satellites?The advantage is flexibility. We are working on the world’s first modularized satellite. A satellite is equipped with various instruments. We treat each of the instruments as a separate module, and we are trying to build a satellite that can perform a variety of tasks with a simple change in the combination of modules.
The basic structure of the satellite is a cube, to which we can add various internal or external modules to accommodate different mission needs. It’s like personal computers that are built on a standard frame but can be loaded with a different CPU, graphics card, memory, etc. Whether the computer is optimized for graphics or office work depends on the customer. Likewise, a satellite can have the same basic frame, with components selected for different applications. We will catalog satellite specifications as much as possible, so we can be flexible in customizing for each mission. It is a new challenge to develop this type of framework - to build a ”semi-made-to-order” satellite by ”modularizing” the parts. Once this project is complete, we will have a lot of flexibility to meet the needs of various scientific satellite missions.
The basic structure of JAXA’s small science satellite is a 1-metre cube. Inside, we plan to use SpaceWire, which is the international standard for communication networks used onboard spacecraft. By standardizing common modules, we will be able to lower costs for the entire satellite series, because we will be able to develop each satellite faster and more efficiently. Our goal is to cut development time by half or more, and do it for a fraction of the budget of conventional scientific satellites.
Q. How often do you plan to launch these satellites?
Epsilon Rocket
SPRINT-A, the first small scientific satellite
We aim to launch three satellites in about five years. We could launch as a piggyback satellite on an H-IIA rocket, but then we’d have a much more restricted choice of the timing of the launch and the orbit. A large-scale satellite project launched onboard a large rocket such as the H-IIA takes a long time to develop, so launches don’t happen often. Therefore, JAXA is also developing a solid-fuel rocket, the Epsilon Rocket, to allow us to launch more frequently and at less cost. Q. What was the motivation behind the development of the small satellite series?JAXA’s Institute of Space and Astronautical Science has frequently launched mid-sized scientific satellites. However, these satellites have become larger and more complicated, as the needs of researchers have increased. Consequently, development time has gotten longer, and cost has gone up, which means scientific satellites are now launched less frequently. Scientific satellites can have many different purposes, such as X-ray observation of a black hole, infrared observation of a celestial object in wide scope, observation of magnetic fields in geospace, and planetary exploration. However, with fewer launches, there are fewer opportunities to piggyback on those launches with smaller, more specialized satellites. This discourages the development of new Japanese technology, and reduces the opportunities for our scientists to get experience working with scientific satellites. This is why it became essential to have a framework for launching scientific satellites faster and cheaper. Q. Why do you think small scientific satellites are needed now? If Japan wants to be the most advanced nation in the field of space science, it is very important to constantly conduct new observations and new research. If no action is taken now, there is great concern that there will be much fewer new scientific satellites within any one area of science.
This will mean less observation, and fewer significant scientific achievements. To prevent this from happening, I think it is important to have the ability to develop satellites quickly and efficiently. This will create more opportunities for scientific satellites from various fields.
In addition, frequent satellite launches will help develop young scientists. Without experience, you cannot grow. But if a scientific satellite is launched only once every 10 or 20 years, it will not only make it difficult for scientists to learn and acquire experience, but will also make it hard for that experience to be passed on from one generation to the next. If that’s the case, we may face a deterioration of Japan’s scientific expertise. I believe that building a series of small scientific satellites can contribute a lot to the development of scientists and the advancement of Japanese science.
