Japan Aerospace Exploration Agency

In-flight receiver calibration of the Ganymede Laser Altimeter (GALA) by passive Earth observations

Abstract. Post-launch characterization of the receiver telescope of the laser altimeter is essential for achieving precise georeferenced planetary measurements and for radiometric calibration to passively measure surface reflectance. For the Ganymede Laser Altimeter (GALA) aboard...

Hour-scale response of low-Earth-orbit satellite altitude to extreme geomagnetic storms revealed by the NinjaSat CubeSat during the 2024 solar maximum

Abstract Extreme geomagnetic storms accelerate low-Earth-orbit satellite decay by inflating the thermosphere, yet the hour-scale pathway from solar-wind energy to atmospheric heating is poorly understood. Using the GNSS receiver of the NinjaSat CubeSat ( $$\sim 500$$ km, $$97^\ci...

Potential of multi-anomalies detection using quantum machine learning

Machine learning is widely used for industrial anomaly detection; however, when anomaly distributions overlap, high false positive rates (FPR) often occur, hindering practical implementation. While quantum kernel methods have been proposed as a solution, the specific conditions u...

Density and Molar Volume of CaO–SiO2–FeO Melts Measured by Electrostatic Levitation Aboard the International Space Station

The densities of CaO–SiO 2 –FeO melts were measured under microgravity conditions using the Electrostatic Levitation Furnace aboard the International Space Station (ISS-ELF). The nominal FeO contents were 20, 60, and 80 mass% (CS20F, CS60F, and CS80F, respectively), with CaO and...

Estimation of auroral emission altitude in the region of the ISS magnetic footprint during a relativistic electron precipitation event observed by ISS-CALET

We report a multi-MeV relativistic electron precipitation (REP) event as observed by the CALorimetric Electron Telescope and the Monitor of All-sky X-ray Image aboard the International Space Station, together with low-cost twin all-sky auroral imagers installed at Athabasca, Cana...

The parent bodies of Ryugu and Ivuna formed before those of other carbonaceous chondrites

Most carbonaceous chondrite (CC) meteorites contain abundant chondrules, millimeter-scale spherical inclusions of previously molten material. Ivuna-type carbonaceous chondrites (CIs) do not contain chondrules, nor do samples of the carbonaceous asteroid Ryugu. CIs and Ryugu share...

Programming sequential deployment of origami via kinematic transition fronts

Propagating transition fronts, in which local interactions sequentially trigger state changes, are widely observed across natural, biological, and engineered systems. While such propagation has been engineered using energy-driven instabilities, front propagation governed purely b...

Stochastic Cruise Speed Control for Time-Based Metering Under Uncertainty

With the increasing demand for air transportation, implementing safe and efficient air traffic management strategies, such as time-based metering operations, which manage the calculated time over (CTO) at designated fixes, has become essential. These operations rely on precise sp...

Effect of oxygen ion irradiation on the visible, infrared, and Raman spectra of Phobos candidate materials: implications on the space weathering by Martian atmosphere-derived ions

Abstract The origin of Martian satellites is still under debate. Nevertheless, such information could give insights into the evolution of the Martian system and planetary formation processes. To address these questions, MMX (Martian Moons eXploration) will conduct spectroscopy (v...

Observation modes of EarthCARE/CPR with different Doppler measurement accuracy: evaluation of their applicability

Abstract. An accurate characterization of cloud vertical motion is essential for understanding cloud microphysical and dynamical processes. The Cloud Profiling Radar (CPR) onboard the Earth Cloud Aerosol and Radiation Explorer (EarthCARE) satellite, launched in May 2024, enables...

Characteristics of tropical clouds with strong updrafts revealed by Doppler-velocity measurements from EarthCARE/CPR

Abstract. Updrafts within clouds are important for the climate system, yet global assessments have traditionally relied on indirect proxies. The EarthCARE satellite's 94 GHz Cloud Profiling Radar (CPR) provides the first global, spaceborne Doppler velocity (Vd) profiles of clouds...

Comparative Analysis of Ion and Electron Contributions to Ionospheric Ionization at Auroral and Subauroral Latitudes

Abstract Electron and proton precipitation into the nightside ionosphere is a key process in magnetosphere–ionosphere coupling. Although auroral electron precipitation at –10 keV is traditionally considered the main driver of auroral emissions, recent studies show that keV electr...

Experimental Development of Gaseous Propellant Mono-Cylindrical Rotating Detonation Engine Film Cooling

Thermal management remains one of the critical challenges in the advancement of rotating detonation engine (RDE) technology for practical propulsion applications. To facilitate progress in this field, this study investigates the use of gaseous film cooling via axial injectors, ai...

Impact of Horizontal Tail Position on Turbulence Transition Around Vertical Tail

The research and development of natural laminar flow (NLF) wing designs can minimize airframe drag. This investigation extends to the design of NLF vertical tails for a reference subsonic civil aircraft under cruise conditions. Although parameters unrelated to design are treated...

Fatigue behavior of ultrasonically welded CF/PPS single-lap joints compared with bulk PPS using entropy-based finite element analysis

In this study, carbon-fiber-reinforced polyphenylene sulfide (CF/PPS) laminates were joined by ultrasonic welding using a PPS interlayer to form single-lap joints, and their temperature-dependent fatigue behavior was investigated within an entropy-based fracture framework. A fati...