  Universal quantum computers require a large network of qubits robust against
errors. Recent theoretical and experimental studies on donor nuclear spins in
silicon, engineered on semiconductor platforms compatible with industrial
fabrication, show their coherent behavior and potential for scalability. Here
we present a hardware-efficient quantum protocol that corrects phase flips of a
nuclear spin using explicit experimentally feasible operations. We introduce
the MAUS encoding (Moment AngUlar System encoding) which uses the large Hilbert
space provided by the nuclear spin of the donor to encode the information and
employ the electron spin of the donor as an ancilla for error correction.
Simulations using present-day experimental manipulation fidelities predict
significant improvement in logical qubit fidelity over existing spin
quantum-error-correction protocols. These results provides a realizable
blueprint for a corrected spin-based qubit.
