CUTE-1.7+APD II (CO-65)

CUTE-1.7+APD II, internationally designated 2008-021C and carrying the NORAD catalog identifier 32785, is a Japanese nanosatellite developed and operated by the Tokyo Institute of Technology. Launched in April 2008, it serves as a successor to an earlier satellite in the same experimental lineage and represents one of several small, university-built spacecraft that helped define the growing field of nanosatellite engineering in the early twenty-first century. The spacecraft is also known informally as CO-65, following the OSCAR (Orbiting Satellite Carrying Amateur Radio) naming convention, which reflects its affiliation with the amateur radio community. As of the time of writing, the satellite remains in orbit.

Mission and Purpose

CUTE-1.7+APD II was conceived as a follow-on to the CUTE-1.7+APD satellite, itself part of a series of progressively refined nanosatellites produced within the academic environment of the Tokyo Institute of Technology. The "CUTE" designation — an acronym associated with the university's CubeSat-scale experimental development program — signals a research orientation rather than a commercial or governmental operational mandate.

The precise mission objectives of CUTE-1.7+APD II are not fully enumerated in publicly available catalog records. However, the broader context of the CUTE satellite series is well established: these spacecraft were designed to validate technologies, gather engineering experience, and provide a hands-on educational platform for graduate and undergraduate researchers working in space systems engineering. The inclusion of "APD" in the satellite's name is widely understood to refer to an avalanche photodiode detector — a device used in optical communication and sensing experiments — suggesting that optical payload technology was a key area of investigation for this spacecraft and its predecessor.

University-class nanosatellites of this era frequently combined educational objectives with genuine scientific or technological demonstrations, and the CUTE series was no exception. By building, launching, and operating their own spacecraft, students and researchers at the Tokyo Institute of Technology gained practical experience across the full lifecycle of a space mission, from design and fabrication through launch integration, on-orbit operations, and telemetry analysis. The satellite's connection to the OSCAR network further indicates that amateur radio operators worldwide could participate in tracking and communicating with the spacecraft, extending its reach beyond the university laboratory.

Orbit and Tracking

CUTE-1.7+APD II occupies a sun-synchronous orbit (SSO), a type of near-polar orbit in which the orbital plane maintains a roughly constant angle relative to the Sun throughout the year. This geometry is achieved by selecting an inclination that causes the orbit to precess at a rate matching Earth's annual revolution around the Sun. The practical result is that the satellite passes over any given point on Earth's surface at approximately the same local solar time on each successive overpass — a property widely valued for Earth observation missions because it ensures consistent solar illumination conditions from one pass to the next.

The spacecraft's orbital parameters place its apogee at 549 km and its perigee at 535 km, yielding a nearly circular orbit with a difference of only 14 km between the highest and lowest points. This low eccentricity is typical of nanosatellites placed in sun-synchronous configurations, where launch vehicles are often tasked with depositing multiple small payloads into a common, well-defined orbit. The orbital inclination is 97.8°, which is slightly retrograde relative to the equator — a characteristic shared by all sun-synchronous orbits, which must tilt past 90° to achieve the necessary nodal precession rate.

At an orbital altitude of roughly 535–549 km, the satellite completes one full revolution around the Earth in approximately 95.3 minutes, meaning it makes just over fifteen orbits per day. Over the course of each 24-hour period, the ground track shifts westward with each successive pass as the Earth rotates beneath the spacecraft, allowing the satellite to eventually cover most latitudes accessible from its inclination. Tracking stations and amateur radio operators around the world can use the NORAD catalog data — including the catalog number 32785 and the COSPAR designator 2008-021C — to generate accurate predictions of when the satellite will be visible or accessible from any given ground location.

Because the orbit is nearly circular and at a relatively low altitude, CUTE-1.7+APD II experiences some degree of atmospheric drag from the outermost reaches of Earth's upper atmosphere, though the tenuous density at 535–549 km means this effect accumulates slowly. The satellite has remained in orbit since its April 2008 launch, indicating that orbital decay has not proceeded to the point of reentry. No decay or reentry date is currently listed in tracking records.

Design and Operator

CUTE-1.7+APD II was built by the Tokyo Institute of Technology, one of Japan's leading technical universities and a longstanding contributor to the country's space research community. The university has a notable history of developing small satellites, and the CUTE series represents a sustained, iterative approach to spacecraft development in which lessons learned from one mission inform the design of the next.

The satellite falls within the nanosatellite category, a classification generally applied to spacecraft with a mass of one to ten kilograms, though the precise mass of CUTE-1.7+APD II is not recorded in the available catalog data and is therefore not stated here. Nanosatellites in this class are frequently built around the CubeSat standard — a modular form factor defined by multiples of a 10 cm × 10 cm × 10 cm unit — which simplifies integration with a variety of launch vehicles and reduces development costs substantially compared with traditional spacecraft. Whether CUTE-1.7+APD II strictly adheres to CubeSat form factor conventions is not confirmed in the verified catalog record.

The manufacturer of the satellite is not separately identified in catalog records, which is consistent with a university-built spacecraft where the operating institution and the development team are effectively the same entity. Tokyo Institute of Technology serves simultaneously as the program's originator, builder, and operator, a common arrangement for academic space programs where the satellite serves as a living laboratory for the institution's own researchers.

The satellite was launched on April 27, 2008, as part of a multi-payload mission — as indicated by the "C" suffix in its COSPAR designator 2008-021C, which signifies the third separately cataloged object associated with that launch event. This kind of rideshare or secondary-payload arrangement is standard practice for university nanosatellites, which rarely command a dedicated launch vehicle and instead secure berths alongside primary payloads or within clusters of small satellites.

Significance and Current Status

CUTE-1.7+APD II occupies a meaningful place in the broader history of university-led nanosatellite development, particularly within the Japanese academic space community. The satellite was launched at a time when the global CubeSat ecosystem was still maturing, and contributions from institutions like the Tokyo Institute of Technology helped demonstrate that small, low-cost spacecraft could be meaningfully engineered and operated outside of traditional governmental or large industrial frameworks.

The follow-on relationship between CUTE-1.7+APD II and its predecessor is itself significant: it reflects an institutional commitment to iterative development, in which a first-generation spacecraft is not simply an endpoint but a stepping stone. This approach — building, flying, learning, and then building again with improved designs — mirrors the development philosophy adopted by many successful small-satellite programs and has since become a widely recognized best practice in the nanosatellite community.

The satellite's current operational status is not confirmed in the publicly available catalog record. Whether its payload systems remain active, whether it continues to transmit telemetry, or whether it has been placed in a passive mode is not documented in the verified data. What is confirmed is that the spacecraft has not reentered the atmosphere and remains a tracked object in Earth orbit, more than sixteen years after its launch.

The association with the OSCAR network (hence the designation CO-65, where "CO" stands for CubeSat OSCAR) connects CUTE-1.7+APD II to a long tradition of amateur radio satellites that have served both communication and educational purposes since the earliest days of the space age. OSCAR satellites have historically been tracked and used by amateur radio operators on every continent, and the designation acknowledges the satellite's compatibility with or contribution to that community.

How to Spot It

Although CUTE-1.7+APD II is a small nanosatellite and not among the brightest objects in low Earth orbit, it may be visible to observers with optical aids under favorable conditions. The satellite orbits at an altitude of approximately 535–549 km and completes a circuit of the globe roughly every 95 minutes, making multiple passes over most locations each day.

Because it is in a sun-synchronous orbit, passes tend to occur at consistent local times — often in the early morning or early evening hours when the spacecraft is illuminated by sunlight while the observer on the ground is in darkness. Using the NORAD catalog number 32785 with any standard satellite tracking application or online prediction service will allow observers to generate precise pass times, maximum elevation angles, and compass headings for their specific location. At its altitude and size, the satellite will appear, if visible at all, as a faint, steadily moving point of light — easily distinguished from aircraft by its lack of flashing lights and its smooth, arc-like trajectory across the sky.