Hiraku Sakamoto, Ph.D.

Expertise:

Structural dynamics. Geometrically nonlinear finite element methods and other computational structural analysis methods. Space structures design, especially design of gossamer systems (membrane and cable space structures). Attitude determination and control systems for spacecraft. Systems engineering and project management for small systems/projects.

Current research projects:

• 3U CubeSat OrigamiSat-2 (operating) - Successfully demonstrated a deployable 5.8-GHz reflectarray antenna using a two-layer textile membrane structure. Launched on April 23, 2026.
• Space Technology Demonstration HELIOS-R, 5G Communications Mission (operating) - Successfully demonstrated a Ka-band active phased-array transmitter mounted on a deployable membrane structure. Launched on December 14, 2025.
• Textile Reflectarray Antenna (formerly supported by the MIC SCOPE program) - Developing large-area deployable reflectarray antennas using a technique for directly plating antenna patterns onto textile substrates.
• 3U CubeSat OrigamiSat-3 (tentative name) - Aiming to demonstrate in-orbit electronic compensation for non-planar deformation of a deployable array antenna.

OrigamiSat-2: on-orbit image

OrigamiSat-2: spacecraft illustration

HELIOS-R: 5G communications payload

Large-area textile reflectarray antenna

Past research projects:

• 3U CubeSat OrigamiSat-1 - led the project that demonstrated the deployment of a multi-functional membrane space structure as Principal Investigator.
• ISAS/JAXA's solar sail project - analyzing deployment dynamics of large membranes, and designing spin-up control laws for contingency deployment sequence
• ISAS/JAXA's next generation space reflector - analyzing structures of a highly precise radio-frequency space reflector considering uncertainties in the system
• Formation generation algorithms for distributed spacecraft systems - conducted experiment at International Space Station (at MIT)
• ADCS design for a small satellite - developed attitude determination and control systems (ADCS) for Citizen Explorer I (at Univ. of Colorado at Boulder)
• Wrinkle free suspension design for membrane space structures - analyzed static and dynamic characteristics of the proposed design (at Univ. of Colorado at Boulder)
• Deflection of inflatable space structures - analyzed bending characteristics of "balloon" structures (at Univ. of Tokyo)

3U CubeSat OrigamiSat-1

JAXA solar sail IKAROS (c) JAXA

JAXA ASTRO-G telescope (c) JAXA

CanSat developed in 2009 by SDDL

MIT-SSL's experimental small satellite on board ISS (c) MIT-SSL	Citizen Explorer I (c) Colorado Space Grant Consortium	Transient dynamic analysis of a membrane using FEM	FEM analysis of inflatable tube's deflection

Lectures:

• ESD.A402 Design Thinking Fundamentals A (graduate level, 1Q)
• ESD.B401 Engineering Design Advanced (graduate level, 2Q)
• ESD.D506 Application of Systems Engineering (graduate level, 3Q)
• MEC.M231 Introduction to Space Engineering (undergraduate level, 3-4Q)
• MEC.Q323 Mechano-Creative Project (undergrad level, 3-4Q)
• ESD.B402 Engineering Design Project (graduate level, 3-4Q)