(Georgia Institute of Technology, 2022-06-08)
Kotani, Kohei
Today, the demand for big data, such as high-resolution images, has been rapidly increasing in space missions. However, the means to achieve multi-Gbps transmission is limited to ethernet, coax, or FFC in CubeSat design. This research describes the development of a lightweight and low-power consumption high-speed communication system suitable for small satellites. A high volume of data from two high-resolution cameras is transmitted to a Raspberry Pi Compute Module 4 running Linux using a fiber-optic link as an interconnect, and the dual images are displayed on a monitor. The FPGA with a high-speed transceiver is extensively used to achieve high-speed communication. It is also verified that the fiber-optic module operates at up to 6.25 Gbps with a power consumption of 90 mW. This research includes the hardware and software development details. All the materials, including the schematics, PCB design, and programming codes, can be found in the Github repository. Furthermore, this thesis includes the discussion of fiber-optic module usage in the space environment and comparing fiber-optic with ethernet, coax, and FFC, along with the selection guides CubeSat developers can refer to. The final deliverable of this research is the high-speed fiber-optic interconnection designed to fit into a CubeSat platform, demonstrating the dual-image display from two HD cameras. The prototype can be extended to implement high-volume data applications such as stereo imaging for proximity operations, free-space inter-satellite links, and high-speed intra-satellite communications for CubeSat platforms.
(Georgia Institute of Technology, 2019-12-01)
Payne, Jacob Hurrell
This thesis investigates instruments for autonomous satellite navigation using
measurements of X-ray emissions from millisecond pulsars. A manifestation of an
instrument for this purpose, called the Neutron star Interior Composition Explorer
(NICER), was launched to the International Space Station in 2017. The NICER
instrument was designed to observe X-ray emissions from neutron stars for astrophysics
research, and is out of scale in terms of volume, power consumption, mass and
mechanical complexity to be useful for small satellite missions. This work surveys the
range of existing X-ray observation missions to tabulate collecting areas, focal lengths,
and optical configurations from milestone missions which describe the evolution of the
state of the art in X-ray observatories.
A navigation demonstration experiment, called the Station Explorer for X-ray
Timing and Navigation Technology (SEXTANT), was conducted using the NICER
instrument. The experimental performance observed from NICER through the
SEXTANT navigation demonstration is compared to theoretical predictions established
by existing formulations. It is concluded that SEXTANT benefits from soft band (0.3-4
keV) exposure to achieve better accuracy than predicted by theoretical lower bounds.
Additionally, investigation is presented on the readiness of a navigation
instrument for small satellites using compound refractive lensing (CRL) and derived
designs. X-ray refraction achieves a much shorter focal length than grazing incidence
optics at the expense of signal attenuation in the lens material. Performance estimates and
previous experimental results are presented as a baseline for physical prototypes and
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hardware testing to support future development of a physical instrument. The
technological hurdle that will enable this tool is manufacturing precise lenses on a 3-
micron scale from materials like beryllium with low atomic mass. Recent X-ray
concentrator concepts demonstrate progress towards an implementation that can support a
CubeSat scale navigation instrument optimized for soft band (0.3-4 keV) X-rays