Space Situational Awareness (SSA) System

Satellites are now part of our imperative infrastructure to support our daily lives such as weather forecasts, disaster monitoring, mapping applications, and so on. However, as of 2017, almost 20,000 artificial objects are known to be traveling around the satellites at a high speed of several kilometers per second, and the number of such objects is increasing. These items are called “space debris” including used satellites and rockets and their fragments. Space debris poses serious threats of colliding with satellites and astronauts as well as crashing down to Earth.
To protect satellites and astronauts from space debris, thoroughly understanding their orbits is essential. Space Situational Awareness (SSA) is a key for such understanding.
JAXA performs 1) monitoring space debris, 2) database compilation of their orbits, 3) analysis of their approach to satellites, and 4) predestination of their re-entry to the atmosphere. In addition, JAXA will set up an optical telescope and radar and an analysis system for orbit information by Japan Fiscal Year 2022 based on the Basic Plan on Space Policy aimed at contributing to SSA activities.
JAXA continues to tackle challenges for a “Safer Space for All.”

Safer Space

We will construct the following three facilities to understand space debris more accurately:

  1. Radar to observe the low orbit range of 200 to 1,000 km, closer to the Earth (orbit of Earth observation satellites etc.)
  2. Optical telescope to observe the high orbit range of 36,000 km (orbit of communication and weather satellites etc.)
  3. Analysis system to understand orbits of space debris, their approach to satellites, and their atmosphere re-entry

When the above three work together as one, our understanding of the area where many satellites are operating will be deepened, so that we will promote “making space visible.”

Japan’s Technology

By maximizing Japan’s technological prowess, we will:

  1. improve observation capability (for example a radar will be able to observe 10 cm class objects compared to the current 1.6-meter at an altitude of 650 km),
  2. increase observation frequency (from 200 times per day to 10,000) and
  3. enhance the processing capacity (for automatic observation planning).

With the above renovations, we will achieve “making space visible”through Japan’s technology

For All of Us

By promoting to “make space visible,” we will accurately understand the conditions of space debris and reduce their collision risks to protect our satellites that are imperative to our lives. We continue our research and development to improve our ability, and achieve a “Safer Space for All (SSA)” through “Space Situational Awareness (SSA).”

SSA facilities


Major specifications

Radar Observation capacity 10 cm class (at an altitude of 650 km)
Number of observable objects at once Up to 30
Optical telescope Detection limit grade 1 m telescope: about 18 grade
50 cm telescope: about 16.5 grade
Analysis system Number of targets Maximum 100,000 objects
Amount of observation data (Radar) 10,000 paths/day
Compiling an observation plan etc. Automatic processing