The big trend in Earth observation missions is to make use of the decreased cost and development time for satellites. This paper argues that recent EO missions are being limited in the planning phase by the optical and physical limits of communications links between node satellites and one hub satellite. The paper surveys previously published papers on swarm missions and proposes future mission configurations that allow commercially available radio frequency communication subsystems which can complete the mission.
Section 2 - the The paper was very helpful in giving a concise section on the ‘Classification of Multi-Satellite missions’
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The current cost of putting up a satellite is between 15,000 and 30,000 $/Kg. Consequently, Nano- and Pico-satellite systems (1–10 kg) could be a motre cost effective method of mission configuration.
Section 3 - Satellite swarm missions
The European space agency (ESA) swarm mission for measuring Earth's magnetic field - detecting Earth's magnetic field. Starling swarm technology demonstration - testing inexpensive distributed systems configurations - 12 cube sats doing synchronized multipoint measurementsSwarms . Small swarms of Silicon Wafer Integrated Femto satellites - technologies for inter-satellite communication networking, and relative navigation,
Section 4 - Fractionated imaging satellite cluster (FISC)
The paper's fourth section goes into details about a mission proposal to target any part of the earth within 7 days using 21 identical 3-U satellites. The ground station can send commands, receive telemetry, and image data every orbital period (i.e. less than 100 min).
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The functions of imaging nodes The functions of Imaging Nodes can be described as follows:- Receive the imaging commands from hub satellite Execute the imaging commands Prepare the imaging and telemetry data and send it to hub satellite
Section 5 - The proposed new conceptual design of satellite swarm for Earth observation applicationsSection five discusses discusses the weaknesses in a FRACTIONATED IMAGING SATELLITE CONSTELLATION configuration. The weaknesses identified were that using laser communication is still under development
And that lazer communications need accurate alignment and powerful actuators which is hard and effects the power budget. The solution is to use a more up to date radio frequency systems and to equip the different component sataliets with satellites with x or s band receivers.
Sections 6 - Results The results and discussions This section introduces how the proposed swarm design will be able to transfer all imaging data using overlapping but traditional (cheaper, lighter) and available RF communication subsystems instead of the optical communication approach.
So basically lasers are outThe , but the paper suggests that Family swarms with different imaging modes will be the ideal configuration for EO missions going forward. Also, optimizing the communications based on the orbit and configuration of the swarm to get the most out of more available technology or components.
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The family swarm will image the Earth in two modes; swath width and high-resolution imaging modes then send data to the ground. These nodes can be described in the following subsection:
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Family swarm data transfer modes The configuration of the family swarm supposes that the M-Sat is flying in the middle of the C-Sats array, so it can communicate with all C-Sats all over the orbital period (i.e. 95 min) in a sequential way. During this communication, M-Sat will receive imaging and telemetry data from C-Sats and send to them the ground commands. F-sat will communicate with M-Sat two times per orbital period (15 min for each session) to receive the imaging and telemetry data, and to send ground commands. Moreover, F-Sat communicates with the ground for 10 min per orbital period (Mahmoud and Farrag, 2015), during this communication F-Sat. will send/ receive imaging and telemetry data/commands to/from the ground. The management of the communication sessions between the family swarm members is planned by the ground station, these communication modes can be classified to
conclusions
The In conclusion, the paper suggests the limitation of this configuration will be maintaining the relative distance between the imaging nodes and avoiding collision,
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