Japan’s ImPACT Program Creates Compact, Lightweight Technology for Compact Synthetic Aperture Radar Satellites

StriX-α synthetic aperture radar image of South Florida on February 8th, 2021 around 12:00 (Japan time). (Credit: Synspective)

TOKYO (JAXA PR) — It has been said that it is difficult to reduce the size and weight of satellite-mounted synthetic aperture radar (SAR) technology, which has been a major technical issue.

At JAXA, based on the SAR technology accumulated in the Earth observation projects so far, the results started from the basic research on the miniaturization and weight reduction of this technology are summarized. 

We have raised the level of technology to practical application in collaboration with Synspective, the Tokyo Institute of Technology Hirokawa Laboratory, Keio University Shirasaka Laboratory and the University of Tokyo Nakasuka/Funase Laboratory.

Synspective’s first demonstration satellite, StriX-α, was launched by Rocket Lab’s Electron rocket from a launch site on the Mahia Peninsula in New Zealand on December 15, 2020, and is in its planned sun-synchronous orbit of 500 km. After entering orbit, StriX-α started operating smoothly and succeeded in acquiring the first image on February 8, 2021. 

The main technologies that have been established are (1) significant miniaturization by arranging the solar cells of small satellites and SAR antennas on the front and back (* 1), and (2) establishment of technology to uniformly irradiate radar from the surface slit of the SAR antenna. (3) Development of high-power amplification technology and large-capacity, high-speed communication equipment that are indispensable for the miniaturization of satellites.

The Cabinet Research Office ImPACT research and development program oversaw the joint development of small satellite SAR technology and the demonstration of it in orbit.

We have realized a small launch and large use at low cost, and advanced the important technology that enables earth observation anytime and anywhere regardless of weather conditions, which is a feature of SAR.

In order to expand the use of this technology, from February 2019, through co-creation activities by the JAXA Space Innovation Partnership (J-SPARC) (* 3) “, we will promote the private use of the technological results obtained from the ImPACT program. We have begun studying future plans and commercializing solutions that utilize SAR constellation technology.

* 1: Select the “passive plane deployment antenna method” as the third method, which is neither the “active phased array method” nor the “parabola method”, which are the two major trends in the world, as the SAR realization method.

* 2: The JAXA Space Innovation Partnership (J-SPARC) is a joint business concept study and exit-oriented with the commitments of both private businesses aiming for space business and commercialization. This is a co-creation type research and development program that creates new businesses by acquiring new technologies by developing and demonstrating the technologies of Japan Aerospace Exploration Agency. 

Since the start of fiscal 2018, we have been promoting more than 30 projects and activities. In addition to pre-dialogue activities, concept co-creation activities, and joint business demonstration activities, we are also promoting activities that contribute to commercialization (consortium management for new market creation, establishment of a common technical base, etc.).
https://aerospacebiz.jaxa.jp/solution/j-sparc/

Roles of Each Institution in Joint Development
of Small SAR satellite “StriX-α”

Synspective

Synspective is developing a group of satellites that enable the development and operation of small SAR satellites and high-frequency observation, selling the data obtained from those satellites, and providing solutions for governments and companies using them.

The company’s first demonstration satellite, StriX-α, was launched by Rocket Lab’s Electron rocket from a launch site on the Mahia Peninsula in New Zealand on December 15, 2020, and is iin its planned sun-synchronous orbit of 500 km. After entering orbit, StriX-α started operating smoothly and succeeded in acquiring the first image on February 8, 2021. 

This is the first time in Japan to acquire images of a private small SAR satellite (100 kg class). Synspective aims to build a constellation (satellite group) of 6 aircraft by 2023 and 30 aircraft in the latter half of the 2020s. With 30 low-Earth orbit constellations, it will be possible to observe disasters in any part of the world within 2 hours (6 aircraft within 24 hours).

Keio University Shirasaka Laboratory

In the ImPACT Shirasaka program, Professor Shirasaka succeeded as the program manager, and the Shirasaka laboratory designed a comprehensive system assuming the operation and service of small SAR satellites. After that, based on a joint research contract with Synspective, we contributed to coordination with various assumed users through research utilizing satellite data utilization methods and networks in various fields developed in the laboratory.

Tokyo Institute of Technology Hirokawa Laboratory

Together with Professor Emeritus Hirofumi Saito of the JAXA Institute of Space and Astronautical Science, he was in charge of developing a lightweight honeycomb waveguide structure flat antenna panel to be mounted on a SAR satellite, a choke flange for non-contact power transmission between antenna panels, and a small power synthesizer. did. In the development of StriX, we are working on improving the characteristics and functionality of the flat antenna panel based on a joint research agreement with Synspective.

Nakasuka/Funase Laboratory, University of Tokyo

In the ImPACT program, the laboratory was in charge of developing a satellite bus that includes a high-power power supply unit and attitude control unit that are characteristic of SAR satellites. In the development of StriX-α, based on the joint research agreement with Synspective, various technologies of microsatellite (general term for satellites of 100 kg or less) that have been developed so far will be applied for short-term and reliable development and operation. Contribution, this StriX-α will be the 13th satellite of the laboratory.