Background and justification:

In this project, a feasibility study for the PULSARS geostationary CubeSat system has been carried out. This involves the definition of a public protection and disaster relief use case using the satellite C-band, evaluation of a 16U CubeSat platform, and investigation into the spacecraft and ground segment technology required for coherent beamforming using a swarm of 20 independent spacecrafts. PULSARS mission design and system architecture are proposed, as well as a programme of technology development, enabling the spacecraft to operate for a minimum of three years.

Communication between crew and ground on future deep space missions will be impacted by communication delay (signal latency), caused by the finite speed of light and radio waves across great distances. The one-way latency caused by the distance between the Earth and the Moon is about 1.3 seconds. The actual latency at lunar distances during the forthcoming Artemis missions is expected to be even higher due to the various signal processing steps associated with the digital communication protocols. Estimates currently vary up to 10 seconds one way.

The millimeter wave domain is also known as the extremely high-frequency (EHF) spectrum ranges from 30 to 300 GHz. Early works on atmospheric propagation in EHF evidenced encouraging future usage for satellite communications. The allocated W-band for satellite services (71-76 GHz and 81-86 GHz) seems to provide a favourable attenuation window related to oxygen absorption. The exploitation of W-band may offer many advantages for wireless communications, which make it suitable for satellite links, such as: broad bandwidths for high data rate information transfer (e.g.

Optical phase beam steering enables motionless pointing of light. The lack of mechanical moving parts not only reduces overall Mass, Volume, and Power (MVP) to a fraction of conventional solutions, but also reduces the associated risk due to friction fatigue. The applications of this technology both on Earth and in Space are only beginning to be fully understood and realised.

Project HyperClass aimed at accelerating the technology to process spectra received from single pixel images of space objects and:

i) extract the material composition of the object,

ii) classify the object according to a set of predefined features,

iii) estimate the attitude motion from the spectral lightcurve.

The authentication of GNSS signals poses a challenging problem. Before exploiting a signal (e.g. its pseudo-noise sequence) it would be desirable for the receiver to have assurance quickly (ideally in less than 10-s) and reliably that the signal is actually coming from a navigation satellite and not from a spoofer (e.g. unknown pseudolite, delayed version of the same signal). Classical data-level authentication solutions work after signal demodulation (PN sequence de-spreading), require data-level cryptography (shared secrets) and key management.

A novel anti-reflection process was demonstrated which improves the quantum efficiency (QE) of a CMOS image sensor, with particular benefits at the ultraviolet (UV) and near infrared (NIR) ends of the electromagnetic spectrum. Also, the dark current and photoresponse non-uniformity (PRNU) were reduced to about 33% and 55%, respectively, of the values for a conventional control sensor. Spatial resolution seemed to be reduced in the NIR, as indicated by MTF measurements, but further investigations are required.

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