K-RadCube

K-RadCube [KASA]

K-RadCube is a South Korean 12U CubeSat developed under the auspices of the Korea AeroSpace Administration (KASA) and manufactured by South Korean industry partners. The satellite will fly as a secondary payload on NASA’s Artemis II mission.

The purpose of the K-RadCube mission is to characterise the radiation environment encountered during transit through the Van Allen radiation belts. These regions of trapped high-energy particles pose a significant risk to human spaceflight beyond low Earth orbit. By operating in a highly elliptical high Earth orbit, the satellite will gather in-situ data relevant to future crewed missions to the Moon and, in the longer term, Mars.

A central objective is the assessment of biological radiation exposure. K-RadCube carries a dosimeter made of material designed to mimic human tissue, enabling direct measurement of radiation dose and analysis of potential biological effects at different altitudes within the belts. This data supports risk modelling for astronauts during Earth–Moon transits.

A secondary mission objective focuses on spacecraft electronics. The satellite carries domestically produced semiconductor devices from Samsung Electronics and SK hynix. Their performance will be monitored to study degradation and failure mechanisms in a high-radiation environment. The results are intended to contribute to research on radiation-hardened semiconductor technologies for future space systems.

K-RadCube was developed by KASA in cooperation with national industrial partners. Propulsion is provided by a water-based system developed by SteamJet. The spacecraft integrates commercial-grade electronics alongside dedicated radiation instrumentation, reflecting a mixed technology approach aimed at both scientific measurement and applied engineering research.

The satellite operates in a deliberately challenging orbit. After deployment it will enter an elliptical trajectory with a period of approximately 24–25 hours, with a perigee initially between 150 and 200 kilometres and an apogee reaching about 70,000 kilometres. This orbit repeatedly traverses the Van Allen belts, enabling measurements across a wide range of radiation conditions.

To avoid rapid atmospheric re-entry after the first orbit, K-RadCube must raise its perigee to about 200 kilometres. This will be achieved through a prolonged propulsion manoeuvre. The SteamJet system is planned to perform a continuous burn lasting around 12 hours, among the longest single burns conducted by a water-based thruster in space, in order to extend the satellite’s operational lifetime.

K-RadCube was launched aboard NASA’s Artemis 2 mission as a secondary payload on the SLS (Block 1) iCPS upper stage. Deployment occured 5 hours and 7 minutes after launch, placing the satellite into high Earth orbit for the start of its radiation measurement mission. After deployment the satellite apparently did not work and likely rentered at the first perigee.