HINODE (SOLAR-B)

Hinode (also cataloged under its pre-launch designation Solar-B) is a Japanese scientific spacecraft dedicated to the study of the Sun, operated by the Japan Aerospace Exploration Agency (JAXA). Assigned NORAD catalog ID 29479 and international designator 2006-041A, it was launched on 21 September 2006 and remains in orbit to this day. The mission represents a significant chapter in solar physics, continuing a lineage of Japanese-led solar observation satellites and bringing together collaborative efforts from the United States and the United Kingdom under JAXA's leadership.

Mission and Purpose

Hinode was conceived as a direct successor to Yohkoh, a previous Japanese solar observatory sometimes referred to as Solar-A. Where Yohkoh broke new ground in X-ray imaging of the solar corona during the 1990s and early 2000s, Hinode was designed to push deeper into the fundamental questions surrounding solar magnetism, the heating of the corona, and the mechanisms that drive solar wind and energetic flare events. These phenomena have consequences that extend well beyond the Sun itself, influencing space weather throughout the inner solar system and affecting satellite operations, communications infrastructure, and power grids on Earth.

The spacecraft carries a suite of scientific instruments aimed at examining the Sun across multiple wavelengths. Its observational program focuses on understanding how magnetic energy generated in the solar interior is transported to the surface and released in the corona — a problem that has occupied solar physicists for decades. The corona's temperature, paradoxically far exceeding that of the underlying photosphere, remains one of the outstanding puzzles in astrophysics, and Hinode's observations have been central to ongoing investigations of this phenomenon.

Collaboration with NASA in the United States and with research institutions in the United Kingdom expanded the mission's scientific reach, enabling a broader distribution of data and cross-disciplinary analysis. The mission's name, Hinode, is a Japanese word meaning sunrise, a name that reflects both the spacecraft's solar focus and a cultural resonance fitting for such a mission.

Orbit and Tracking

Hinode occupies a Sun-synchronous orbit (SSO), a specialized class of near-polar orbit in which the orbital plane precesses at a rate that keeps it aligned with the Earth-Sun direction throughout the year. This geometry is particularly valuable for a solar observatory because it allows the spacecraft to cross the day-night terminator on each pass, resulting in near-continuous sunlight exposure and correspondingly extended — in some seasons nearly uninterrupted — views of the Sun without the periodic eclipse interruptions that would affect a more conventional orbit.

After launch, Hinode underwent an orbital adjustment phase. Its initial trajectory placed it in a highly elliptical path, but the satellite subsequently maneuvered into the quasi-circular Sun-synchronous configuration it occupies today. Current tracking data places the spacecraft at an apogee of 682 km and a perigee of 658 km, indicating a very nearly circular orbit with only about 24 km difference between the two extremes. The orbital inclination stands at 98.1°, consistent with the retrograde tilt required to maintain Sun-synchronous precession. Hinode completes one full orbit of Earth approximately every 98.0 minutes, meaning it circles the planet roughly fourteen to fifteen times per day.

This orbit keeps the spacecraft at a relatively stable altitude well within low Earth orbit, which facilitates regular contact with ground stations and allows for efficient scheduling of observations. Tracking services, including those provided by this site using data derived from the NORAD catalog, can predict the spacecraft's ground track and overhead passes with high precision using its catalog entry under ID 29479.

Design and Operator

Hinode is operated by the Japan Aerospace Exploration Agency, the Japanese national space agency responsible for both civilian space development and aeronautical research. JAXA was formed in 2003 through the merger of three previously independent Japanese space and aviation bodies, and it has pursued an active program of Earth observation, planetary science, and astronomical research missions. Hinode falls under the agency's solar and heliospheric science portfolio.

The spacecraft was launched aboard an M-V rocket — a solid-fueled launch vehicle developed in Japan — from the Uchinoura Space Center in Kagoshima Prefecture, on the southernmost island of Kyushu. This launch was notable for being the final operational flight of the M-V rocket, a vehicle that had served JAXA's predecessor organization for more than a decade before being retired in favor of newer launch systems. The liftoff took place in the late hours of 21 September 2006 local time (converting to 22 September 2006 in UTC), and Hinode was successfully placed into its planned initial orbit.

Specific information regarding the spacecraft's mass and detailed physical configuration is not recorded in the public satellite catalog. The manufacturer of the spacecraft bus is similarly not listed in publicly available catalog data. What is documented is that Hinode is classified as a payload — meaning it is the primary operational object from its launch event, as distinct from rocket bodies or debris also generated during the same launch — and it is registered to Japan.

Scientific Contributions and Status

Hinode's first scientific images from its onboard instruments were captured in late October 2006, just weeks after reaching its operational orbit. In the years since, the spacecraft has produced an extensive and widely cited body of observations covering solar flares, the dynamics of sunspots, coronal mass ejections, and the fine-scale structure of the solar magnetic field. Its data have contributed to numerous peer-reviewed publications and have informed models of space weather forecasting.

One of Hinode's enduring contributions has been high-resolution imaging of the solar surface magnetic field, allowing researchers to track how concentrations of magnetic flux emerge, evolve, and ultimately dissipate. This has refined understanding of how energy is stored and released in active regions — the areas of intense magnetic activity that produce flares and coronal mass ejections capable of disturbing Earth's magnetosphere.

The spacecraft has now been operational for well over a decade and a half, significantly outlasting many original design expectations for missions of its class. While the current mission status is not specified in the public catalog record for this object, the orbital data confirm that Hinode remains in orbit. Extended missions of this kind are common for well-functioning spacecraft when scientific return justifies continued operations, and Hinode has been recognized internationally as a productive long-duration solar observatory.

The mission has also served as a model for collaborative frameworks in solar science, demonstrating how national space agencies can pool expertise and share scientific returns across borders. Observations from Hinode have frequently been coordinated with those from other solar observatories, both space-based and ground-based, creating multi-perspective datasets that no single platform could produce alone.

How to Spot It

Hinode orbits at altitudes between 658 km and 682 km, within the zone of low Earth orbit where many satellites are visible to the naked eye under the right conditions. Its Sun-synchronous orbit at 98.1° inclination means the spacecraft passes over a wide range of latitudes, including much of the populated Northern and Southern Hemispheres, making it geometrically accessible to observers at most locations on Earth.

Whether Hinode is actually visible from the ground on any given pass depends primarily on the spacecraft's size and reflectivity — neither of which is specified in the public catalog record — as well as on local sky conditions and the timing of the pass relative to local twilight. Satellites at this altitude are typically visible during the hours around dawn and dusk, when the observer is in darkness but the orbiting object is still illuminated by sunlight. Hinode completes a full orbit in about 98.0 minutes, so multiple passes may occur in a single evening under favorable conditions.

To determine whether Hinode will be visible from your location, use the tracking tools available on this site. By entering your geographic coordinates and selecting Hinode from the catalog (NORAD ID 29479), you can generate accurate pass predictions including the time, direction, and maximum elevation of each upcoming pass. Passes that rise high in the sky — above 30° to 40° elevation — are generally the easiest to spot, while low-horizon passes may be obscured by buildings, trees, or atmospheric haze.