The Multi-layer Acoustic & Conductive-grid Sensor (MACS) Technology Demonstration on HTV-X3

Millimeter-sized orbital debris (OD) represents the highest penetration risk to spacecraft operating in low Earth orbit (LEO). However, there is a lack of direct measurement data on such small debris in the environment, leading to large uncertainties in the OD risk assessments for mission support. To address this critical data gap, the NASA Orbital Debris Program Office (ODPO) has explored various particle detection technologies for in situ measurements of small OD since the early 2000s. The effort has led to the development of the Multi-layer Acoustic & Conductive-grid Sensor (MACS), a collaboration with JAXA.

MACS combines several simple particle impact detection principles to maximize information that can be extracted from each debris detection for high quality data. Such measurement data is needed to support meaningful improvements to the modeling of the millimeter-sized OD populations and increase the fidelity of OD impact risk assessments, which will enable the development and implementation of cost-effective protective measures for the safe operations of future space missions. To fully advance the technology readiness level (TRL) of MACS, a technology demonstration of MACS on a JAXA H-II Transfer Vehicle (HTV) mission in early 2027 has been confirmed. A successful demonstration of MACS will pave the way for using MACS to address the critical data gaps on the millimeter-sized OD at 600-1000 km altitudes in the future. This paper provides a summary of the rationale, MACS technology development, and preparation for the upcoming HTV-X technology demonstration mission.