AOBA-VELOX: small impulses and future exploration

AOBA-VELOX III was developed by NTU and Japan’s Kyushu Institute of Technology, often called Kyutech. It travelled to the International Space Station in December 2016 and was deployed from Japan’s Kibo module on January 16, 2017. The archive uses AOBA-VeloxIII. Cargo transport brought it to the station; release began its independent flight as a small spacecraft.

A locally preserved NASA photograph records the satellite near the deployment hardware. It gives learners a direct view of the size and setting of the operation. A photograph of release cannot show every subsequent electrical or propulsion result, however. Engineers use telemetry and experiment records to connect the visible hardware with its actual behavior after deployment. The image and those measurements answer complementary questions.

The project included pulsed plasma propulsion, which produces brief impulses rather than a single long chemical-engine burn. Impulse — open definition is force accumulated over time and equals the corresponding change in momentum. Small repeated impulses can be useful when a spacecraft needs controlled adjustments, but their effect depends on direction, vehicle mass and the rest of the control system.

Take a fictional thruster delivering twenty micronewton-seconds per pulse. One hundred identical pulses aligned in the same direction provide two thousand micronewton-seconds, or two millinewton-seconds. This arithmetic illustrates accumulation; it is not an AOBA flight-performance report. Pulses directed in opposing directions would not simply add to the same net momentum change. The direction of an impulse matters as much as its magnitude.

A pulse changes momentum

AOBA-VELOX IV launched in January 2019. NTU describes an Earth-orbit mission using low-light imaging and propulsion work to prepare technologies relevant to possible future lunar exploration. Its archive card is Aoba-VELOX IV. The camera’s investigation of faint Earthglow did not mean the spacecraft was orbiting the Moon or had photographed a lunar surface phenomenon directly.

A demonstration is most useful when its tested environment and remaining gaps are explicit. Conditions near the Moon can differ in communications geometry, thermal exposure and radiation, so a successful Earth-orbit trial is one step toward a later mission. The AOBA partnership shows how universities can divide expertise and test manageable pieces of a larger ambition while keeping the achieved flight separate from the proposed destination.