Quantum Experiment Satellite Testbed (QUEST)
Mission Overview
The mission aims to demonstrate the feasibility of implementing a CubeSat-based trusted-node Quantum Key Distribution (QKD) testbed in low Earth Orbit as well as a relatively portable optical ground station receiver.
The mission is funded by the Air Force – University Nanosatelite Program (UNP)
The QKD payload consists of a weak coherent photon source (based on the BB84 QKD protocol) and an optical tracking system. The on-orbit QKD transmitter, Alice, will send polarization encoded keys to the optical ground station, Bob. Due to the quantum statistical nature of photon polarization states, errors and eavesdroppers can be detected in the key transmission, thus making the key exchange secure for use with a variety of encryption protocols, e.g., AES-256 or one-time pad (Vernam cypher).
Experiment
(1) The satellite slews to the optical ground station and begins tracking.
(2) Ground station tracks the satellite with a beacon laser. The optical payload onboard the satellite uses the uplink beacon to direct the pointing of the downlink laser.
(3) The optical payload downlinks the weak coherent pulse to the optical ground station.
(4) Beacon tracking and QKD downlink ended,
(5) Mission data is transmitted to the ground station and the satellite exits experiment mode.
Subsytems
EPS – custom designed and built in-house, Li-ion batteries, solar panels to be procured from commercial vendor
ADCS – Cubespace 3-Axis ADCS with star tracker, deployable de-orbit tapes for End-of Life
CDHS – Beaglebone Black Industrial OBC on custom CDHS PCB along with Novatel OEM719 GPS + Taoglas antenna
COMMS – custom designed and built in-house UHF TT&C radio with crossed dipole antennas
MECH – custom design and manufactured in-house monolithic 6061 aluminum structure
PAYLOAD – QKD polarization-encoding QKD source (infrared) with fine steering mirror beacon tracking system
OPTICAL GROUND STATION – 0.5 meter class tracking telescope, BB84 receiver optics, single photon avalanche photodiode detectors, high time resolution event time tagger.
