What Sony’s Spresense sent back from Space

By Jerry Bartlett, April 12, 2022
Spresense In Space OperationSpresense In Space Operation

April 12, 2022: Back in November 2021, we wrote about how Sony’s Spresense microcontroller board was launched into space as part of a payload for the mission in the program Innovative Satellite Technology Demonstration No. 2 on the RAISE-2 satellite by the Japan Aerospace Exploration Agency (JAXA). The tasks of this first mission on the RAISE-2 satellite have been completed and the results are back.

The Spresense board (left) before it goes into its space capsules (right) for the RAISE-2 satellite: the space-facing SPR-BOX-S and the earth-facing SPR-BOX-E.

Mission overview: Spresense looks to Earth and deep space

The purpose of this mission on the RAISE-2 satellite was twofold:

  • To evaluate the durability of Spresense in the harsh environment of space.
  • To use Spresense on-board technologies for estimating attitude (positioning and orientation) of the satellite.

As you can see in the image at the head of this article the RAISE-2 satellite was equipped with two Spresense boards, one “Earth-facing” (called SPR-BOX-E) and one (called SPR-BOX-S) directed out into deep space. The durability and attitude estimation tests were performed on both the S and the E boxes, with the attitude tests performed with the aid of the GNSS antenna plate (SPR-GAP).

The durability evaluation consisted of evaluating both the durability of both the Earth-facing and space-facing Spresense main boards, and the Spresense camera boards in orbit. The Earth-facing camera board for taking photos of the Earth’s surface and the high-sensitivity camera on the space-facing camera board for taking photos into deep space, which could be used for detecting space debris.

The antenna arrays in the SPR-GAP box connect into each Spresense main board unique attitude sensing technologies. This enables Spresense to estimate satellite attitude in three ways:

  • Using Sony’s newly-developed, ultra-high-precision IMU.
  • Calculating the phase difference of the positioning satellite system (GNSS) carrier wave.
  • Using calculations based on capturing images of the Earth’s surface and the stars.

The setup was evaluated to see if they would be suitable for improving the autonomous control performance of satellites and probes. Ultimately, the purpose of the mission is to see if Spresense has the potential to be the next-generation spacecraft controller.

Mission results and progress so far

Mission status Spresense for Earth (SPR-Box-E)

Test Progress Evaluation status
Durability evaluation
Spresense main board, facing Earth.		 Going well Confirmed that the system is operating without any problems in space. No resets due to software errors have been detected to date.
Durability evaluation
Spresense camera board, facing Earth.		 Going well Successfully took pictures of the Earth’s surface.
Satellite attitude estimation
Attitude estimation by tests using data acquired from the SPR_GAP antennas.		 Going well Confirmation that attitude data is being acquired. Attitude data from RAISE-2 is being obtained to confirm the accuracy.

 

The Caribbean Sea, as seen by the Spresense Earth-facing camera, on-board the RAISE-2 satellite. © Sony Semiconductor Solutions Corporation, 2022.

Mission status Spresense for Space (SPR-Box-S)

Test Progress Evaluation status
Durability evaluation
Spresense main board, facing deep space.		 Going well Confirmed that the system is operating without any problems in space. No resets due to software errors have been detected to date.
Durability evaluation
High-sensitivity Spresense camera board, facing deep space.		 Going well Successfully photographed deep space. Methods for separating stellar and white point noise are under investigation. After that, matching with constellations will be considered.
Satellite attitude estimation
Using three antennas based on the phase difference of the positioning satellite system (GNSS) carrier wave.		 Going well Confirmation that the positioning module is outputting the data necessary for positioning and attitude estimation. Attitude data of RAISE-2 is being obtained to confirm the accuracy.

Satellite positioning data obtained by the Spresense GNSS carrier wave system on board the RAISD-2 satellite.

Summary of mission results

All six test parts of the mission are declared to have the status “Going well”.

  • The commercially available Spresense main board and Spresense camera board were both confirmed to operate without failure during rocket launch and in Earth orbit in the environment of space.
  • The Spresense main board successfully obtained satellite positioning using the built-in positioning module. Satellite positioning requires special firmware.
  • Attitude estimation by the data acquired by the Spresense boards from the GNSS antenna array  and by the phase difference of the positioning satellite carrier wave will be verified in the future.
  • Attitude estimation using camera images like star trackers will be verified in the future.

Everything looks promising, but further missions are needed to confirm the operation of the GNSS antenna technology, and to optimise the operation of space-facing cameras for satellite attitude estimation. This mission brings us a step closer to using Spresense technology for controlling satellites and other spacecraft.

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