Exclusive Tour at JAXA
Japan Aerospace Exploration Agency (JAXA) is the NASA of Japan. JAXA has three major campuses/ space centers located in: (1) Chofu, Tokyo (2) Tsukuba, Ibaraki (3) Sagamihara, Kanagawa. At the time of my visit in the Chofu headquarters, I was doing my research at the National Astronomical Observatory of Japan (NAOJ) which is just 20 minutes walk from here and another 20 minutes walk from my house. This is my third time to visit JAXA. During the first one I was with an Indonesian friend, Stevanus, who is an Astronomy student at Tohoku University. During the second visit, I accompanied my Taiwanese friend, Chia-Hui, who is an exchange student at Osaka University.
This third visit was very special because I had the special access to see actual experiments within facilities and laboratories which is much way more awesome than my previous experience wherein I just saw just the public museum.
(1) Supercomputing Lab
TOP LEFT: control monitor of supercomputer. TOP RIGHT: Supercomputer viewed from the window.
I learned that before JAXA was established, there is a mother institution which had supercomputers way back 1950s. Since then, they upgraded their supercomputers almost every decade. In the early 2000's, CeNSS supercomputer pictured below used the most advanced memory and CPU modules at the time. Thanks to continuous miniaturization of computing technologies, this enabled more components to be packed into smaller space to do more computation at a relatively lower energy cost. The current supercomputer called SORA-MA (sora means sky in japanese) boasts a peak performance of 1.31 PFLOPS, or peta flops where peta means 10^15 and flops is floating point operation per second. In comparison, a desktop with a single-core 2.5 GHz processor has a theoretical performance of 10 billion FLOPS = 10 GFLOPS (in theory). Thus, the SORA-MA supercomputer is more than 1 million times more powerful (in terms of raw computational speed) than an ordinary desktop computer. SORA-MA has 40TB memory and 1296 nodes with 32 cores/CPU. This year, another upgrade is scheduled to increase the performance to 3 PFLOPS, 90TB memory, and 3000 nodes.
This is the quick view of all the 1296 nodes (216 nodes each layer). There is color coding for task management where a block with same color represents the occupied portion of the supercomputer doing similar task (e.g. simulation). A software is developed for task management and this is cannot be done manually by a person.
I learned that in a supercomputer system, there are many support subsystems aside from the main subsystem like above. The Pre-Post system, the Large Memory System, the Login System, the Control and management system, and finally the File System.
These supercomputers are used for state-of-the-art aerospace simulations. For example, they test how to design rockets and other air vehicles such as helicopters and airplanes that are efficient, quiet and safe. Usually, the output of these simulations are numerical values. The time evolution of these resultant parameters are shown in a toy video. What's cool about JAXA supercomuting lab is that they also make tangible model visualizations such as 3D printed rocket engine model.
(2) Hypersonic Wind Tunnels (HWT)
The HWT is a facility for hypersonic flight testing since 1965. The tunnel provides data on aerodynamic forces, moments, pressure distribution and aerodynamic heating. There is a 0.5m and 1.2m-diameter wind tunnel. The first one provides wind flow speed in the order of Mach 5, 7, and 9 and the second one of Mach 10. 1 Mach is equal to the speed of sound in air which is about 350 m/s.
TOP LEFT: A simple wind tunnel shown in the museum. The white object in the middle of the blue tunnel is a toy model of the of an airplane wing. When the wind is blowing, the wings can experience a force that will either lift or drag itself depending on its orientation relative to the wind direction. This principle shows how planes fly basically. TOP RIGHT and BOTTOM LEFT: Different view of the wind tunnel facility. It consists of various specialized pipes and chambers where air flows until it attains desired speed. BOTTOM RIGHT: Model of a aircraft nosecone is installed in the chamber for testing.
The facility is pretty complex. The first question is how to attain specific wind flow with hypersonic speed? Clearly, conventional mechanical fans are not enough. The key to the design is the use of high air pressure tanks and vacuum tanks (shown in the diagram below). First, air is pumped into tank one with pressures in the order of 13 Mpa. Once valve is released, the air is flown toward the other tank which is near-vacuum with pressures of 100 Pa (or 10e-3 atm). Air pressure is key to attaining hypersonic flows. A chamber is installed midway to place the test model and sensors. However, there are several problems that need to be addressed. One is air liquefaction wherein air condensation occurs when the air at room temperature is expanded adiabatically to hypersonic speeds. Thus, a pebble-bed air heater is installed to heat the air flowing through it. The test lasts for about 1-2 minutes.
The entire facility can be controlled from the main control room on the second floor. The computers look pretty old but they're powerful! The software is specially designed for this purpose. The monitors on the top part of the picture below shows the different views within the facility. The center monitor shows the model being tested inside the chamber.
(3) Museum
TOP ROW: Different rocket engines developed by JAXA. MIDDLE ROW: Different experimental supersonic aircrafts. BOTTOM LEFT: Cockpit of one of the first Japanese commercial airplanes developed in the 70's. BOTTOM RIGHT: Space mission simulator to the Space Station and Moon.
(4) Tracker or space objects in LEO
The facility is just a small observatory with 18in SCT main telescope and other wide field refractors. Its task is to monitor space debris in Low Earth Orbit and determine their orbits. NASA compiled about 17,000 space objects larger than 10cm in their database.
There are more labs in the Chofu space center such as labs where advanced materials and technologies are developed but these are the only labs I was able to visit. However, I still think this is a wonderful and insightful experience already. The field of aerospace research is really awesome!