TAMPA, Florida — Five Earth observation satellites from Japan’s Axelspace mission are helping NorthStar Earth and Space track orbits ahead of Canada’s proposed Space Situational Awareness (SSA) constellation.
An on-board software update has allowed satellites to collect SSA data during periodic trips to the dark side of the planet in low Earth orbit (LEO), the companies announced Jan. 11.
During those dark periods when satellites are not needed for Axelspace’s image-taking customers, their cameras can be pointed away from Earth to capture objects above them.
Each 100-kilogram GRUS satellite built by Axelspace for the AxelGlobe constellation is equipped with “advanced attitude control to flexibly respond to a variety of imaging needs,” said Yuya Nakamura, CEO of Axelspace.
Satellites can collect data on LEO objects above their own operational altitude 585 kilometers, NorthStar said, apart from mean earth orbit (MEO) and geostationary orbit (GEO).
The companies did not provide further details on AxelGlobe’s ability to monitor near-Earth orbits, including the size of the objects it can track and the frequency of data collection.
According to NorthStar, the companies did not have to seek regulatory approval to allow Axelspace to point the cameras both up and down.
The satellites are designed to take grayscale images of the Earth at a resolution of 2.5 meters, the minimum perceptible distance between two separate objects on the ground. On-board sensors can also capture color photos of the Earth, including near-infrared, with a resolution of five meters.
Mitigation of potential delays
North Star recently raised $35 million for plans to deploy a constellation of 24 satellites to track objects as small as one centimeter in LEO, around seven centimeters in MEO, and around 40-50 centimeters in GEO.
The first three satellites, built by Spire Global, were scheduled to be launched in mid-2023 with Virgin Orbit.
However, Virgin Orbit suffered a launch failure on January 9, raising the prospect of delays for NorthStar as researchers investigate an anomaly which prematurely shut down the upper stage of the rocket.
Combining existing sensor data from AxelGlobe with NorthStar’s proprietary algorithms “is a highly effective way to improve the quality of commercial SSA services available to operators,” said NorthStar CEO Stewart Bain.
He added that NorthStar is “working with customers in evaluating” the SSA data from Axelspace as the company builds services ahead of the launch of the first satellites.
This data is integrated with SSA information from other partnerships, including one NorthStar announced in 2019 with ExoAnalytic Solutions, an American company that uses a network of ground-based telescopes to track satellites and space debris.
Commanding the EO spaceship
Repurposing Earth imaging satellites to capture data in near-Earth orbits is not unusual in the space industry.
High Earth Orbit Robotics, an Australian startup, is under construction In-orbit inspection gallery through partnerships with earth observation operators.
NorthStar says its partnership with Axelspace is for determining the SSA’s orbit, not taking pictures for inspection purposes.
NorthStar does not process split images, the company added, and associates observed space objects with known identities using different metrics and characteristics than observed physical characteristics, such as their general shape.