SEEDS II (CO-66)

SEEDS II (CO-66) is a Japanese amateur nanosatellite developed and operated by Nihon University as part of an educational initiative to give students hands-on experience in spacecraft engineering. Catalogued by NORAD under the identifier 32791 and assigned the international designator 2008-021J, the satellite was lofted into orbit aboard an Indian Space Research Organisation PSLV rocket, launching on 27 April 2008. It occupies a sun-synchronous low Earth orbit and remains in orbit to this day. The designation CO-66 places it within the long-running series of amateur radio CubeSats assigned callsigns under the CubeSat Oscar numbering convention.

Mission and Purpose

The full name of the satellite — Space Engineering EDucation Satellite 2 — makes explicit what the project is fundamentally about: education. Nihon University's program was designed to provide its students with the rare and demanding challenge of conceiving, designing, constructing, and operating an actual spacecraft, compressing into an academic environment the same engineering disciplines that professional satellite programs require. The program belongs to a tradition of university CubeSat projects that proliferated in the early 2000s, in which small, standardized form factors allowed institutions with modest budgets to participate meaningfully in space activities.

The "2" in the satellite's name reflects the program's difficult history. An earlier iteration, simply known as SEEDS, was built toward the same educational goals but never reached orbit; it was lost when the Dnepr launch vehicle it had been assigned to failed during a launch attempt in July 2006. That failure represented a significant setback for the student team, destroying not only the hardware but the accumulated effort behind it. Rather than abandoning the effort, Nihon University undertook the construction of a successor spacecraft designed to carry on where the original had been intended to go. SEEDS II thus carries with it a measure of institutional determination that gives its eventual successful launch additional weight.

The satellite was built to the CubeSat standard, placing it in the category of nanosatellites — spacecraft small enough to be accommodated as secondary payloads on larger launch vehicles, and inexpensive enough to be realistically constructed by university teams. Among the capabilities commonly associated with university CubeSats of this period are amateur radio transponders and beacon transmitters, which allow the spacecraft to communicate with ground stations and amateur radio operators globally and also serve as a practical demonstration of RF engineering skills developed during construction. The satellite is associated with the amateur radio designation CO-66, indicating its participation in the broader amateur satellite community. The precise mission instrumentation carried by SEEDS II is not publicly catalogued in detail in official tracking records.

Orbit and Tracking

SEEDS II orbits in a sun-synchronous configuration, a class of near-polar orbit in which the orbital plane maintains a roughly fixed orientation relative to the Sun throughout the year. This geometry ensures that the satellite passes over any given point on Earth's surface at approximately the same local solar time on each successive pass, a property that makes sun-synchronous orbits particularly useful for Earth observation, where consistent lighting conditions simplify image comparison. Whether SEEDS II makes active use of this characteristic for observational purposes, or whether the orbit was chosen primarily as a consequence of the shared launch vehicle's trajectory serving other payloads, is not recorded in available catalogs.

At the time of the most recent orbital data, SEEDS II maintains an apogee of 474 km and a perigee of 471 km — a remarkably circular orbit with less than 3 km of difference between its highest and lowest altitudes. The orbit is inclined at 97.8° to the equator, which is consistent with sun-synchronous geometry and means the satellite travels on a retrograde path relative to Earth's surface rotation. The orbital period stands at 93.9 minutes, meaning the spacecraft completes slightly more than fifteen full revolutions of the Earth every day.

At these altitudes, atmospheric drag is low but not entirely negligible over long timescales. The satellite has nonetheless remained in orbit since its 2008 launch, accumulating well over a decade and a half of continuous operation or at least physical presence in space. Tracking data for SEEDS II is maintained under NORAD catalog number 32791, and the object's trajectory can be followed through space surveillance networks that monitor the low Earth orbit environment.

Design and Operator

SEEDS II was built by students at Nihon University, one of Japan's largest private universities, which has maintained an active presence in small satellite development. The satellite conforms to the CubeSat standard, a form factor originally defined jointly by California Polytechnic State University and Stanford University in the late 1990s, which specifies a basic unit of 10 × 10 × 10 centimeters. CubeSats are typically launched as secondary payloads from a standardized deployer, allowing them to share ride costs with primary missions. The manufacturer of SEEDS II is not identified in publicly available catalog records, though attribution of the construction work naturally falls to the Nihon University team itself.

The satellite's mass is not publicly recorded in the tracking catalog. CubeSats conforming to the single-unit standard generally fall within a mass envelope of roughly one kilogram, though this figure is not confirmed for SEEDS II specifically and should not be taken as authoritative for this spacecraft.

The launch was carried out by the Indian Space Research Organisation using a Polar Satellite Launch Vehicle, which has established itself as a reliable workhorse for the deployment of Earth observation and small secondary payloads. The PSLV's capacity to accommodate multiple secondary payloads in a single launch made it well suited to the deployment of university CubeSats alongside larger primary missions. SEEDS II shared its ride with a number of other small satellites, a common arrangement for nanosatellites of this class during the period.

The country of registry for SEEDS II is Japan, reflecting both the institutional affiliation of the operator and the standard practice of attributing satellite ownership to the nation in which the responsible organization is based.

Legacy and Current Status

SEEDS II occupies a small but genuine place in the history of Japanese university space activities. Its very existence is partly a testament to the resilience of the Nihon University team following the loss of the original SEEDS spacecraft in 2006. For student satellite programs, the destruction of a payload before launch represents a particularly discouraging outcome — the hardware that students built and tested is gone, and no operational data is ever returned. The decision to rebuild and try again produced a successor that successfully reached orbit and thereby validated the educational investment the program represented.

Within the broader landscape of the CubeSat era, SEEDS II arrived at a time when small university satellites were still demonstrating that modest budgets and student workforces could produce spacecraft capable of surviving launch and functioning in the space environment. Programs like SEEDS II contributed to building the institutional knowledge and the culture of small satellite development that has since expanded into commercial and governmental sectors.

The current operational status of SEEDS II is not recorded in publicly available tracking catalogs. Many satellites of this class have exceeded their originally anticipated operational lifespans while their physical hardware remains in orbit even after transmitters fall silent. SEEDS II remains a tracked object, its orbit well characterized by space surveillance networks, regardless of whether it continues to perform any active function.

How to Spot It

SEEDS II orbits at an altitude of roughly 471 to 474 km in a nearly circular sun-synchronous orbit, completing a full revolution every 93.9 minutes. At that altitude and with its CubeSat dimensions, the satellite is a faint object by any measure, and unaided-eye observation is not generally feasible for spacecraft of this size class. Dedicated amateur observers equipped with optical aids and accurate pass prediction software have tracked CubeSats of comparable dimensions, but favorable conditions — including a night pass close to the observer's location with the satellite sunlit against a dark sky — are required even for optical detection.

For those interested in amateur radio reception, the CO-66 designation indicates SEEDS II's recognized status as an amateur satellite, and receiver-equipped observers may be able to attempt reception of any beacon or downlink signal should the spacecraft remain active on its licensed frequencies. Up-to-date pass predictions using catalog number 32791 will yield the most accurate timing for any observation attempt at a given location.