Their solution has been to develop satellites made mostly of wood, which will burn completely upon reentry.
The first such wooden satellite is planned to be launched in September. It is intended mainly for collecting data about the behavior of wood in the outer space, e.g. on wood expansion, contraction and degradation, along with internal temperature and electronic equipment performance.
An alternative to wood would be the use of synthetic polymers, but those are typically more sensitive to radiation, so more research would be needed for finding a suitable plastic and appropriate additives to decrease the radiation sensitivity.
Wood or plastic would not be suitable for ships hosting humans, because they are not hermetic, but they may be an acceptable choice for satellites with a short lifetime and with much more relaxed constraints for the composition and pressure of the internal atmosphere (which may not be needed at all, e.g. when the internally produced heat reaches the external radiant cooling surfaces through solid paths or through pipes with circulant liquid).