Loose Optical Fiber Tether for Multi-Satellite Communication
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Solution Overview
Problem
Current satellite communication systems face limitations in achieving high data rate communications between satellites due to the narrow beamwidth of free-space optical links, which require precise alignment and are not suitable for multi-satellite configurations, especially in small satellites, and omni-directional RF or wide-beam links act as bottlenecks.
Innovation Solution
A multi-satellite system utilizing closely spaced satellites connected by a loose optical fiber tether, allowing independent steering of free-space optical beams without affecting neighboring satellites, enabling higher data rate communications without the need for large and heavy 2-axis gimbals, and allowing for electrical power transfer and maintenance of satellite spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If body-steering or 1-axis gimbals are used for FSO beam alignment, then a single independent FSO beam can be achieved, but multiple simultaneous communication paths between satellites cannot be established
Solution Approach 1:
The system divides the satellite constellation into multiple independently controllable satellites, each capable of generating its own FSO beam. This segmentation allows multiple simultaneous communication paths without requiring complex gimbal mechanisms on each satellite, as each satellite independently controls its own beam direction through body orientation.
Solution Approach 2:
Each satellite in the constellation serves multiple functions: it acts as both a communication node and a beam source, and can communicate with multiple different satellites simultaneously through independent FSO links. This multi-functionality eliminates the need for specialized gimbal mechanisms dedicated to single-beam control.
2Measurement precision
If 2-axis gimbals are used for precise FSO beam alignment, then accurate pointing can be achieved, but the size, weight and manufacturing precision requirements become prohibitive for small satellites
Solution Approach 1:
The invention extracts the complex 2-axis gimbal mechanism from the small satellite system and replaces it with simpler body-steering methods. The pointing accuracy is achieved through precise control of the satellite's own orientation rather than through additional gimbal hardware, thereby eliminating the weight and complexity burden on small satellites.
Solution Approach 2:
Instead of physically implementing heavy 2-axis gimbals on each small satellite, the system uses software-controlled body orientation to replicate the pointing function. The satellite body itself becomes the mounting structure for the FSO transceiver, copying the functional capability of gimbals without the associated mass penalty.
3Reliability
If taut optical fiber tethers are used to connect satellites, then physical connection is maintained, but movement of one satellite causes movement of others and degrades communication reliability
Solution Approach 1:
The system uses a loose, flexible optical fiber tether instead of a rigid or taut connection. This flexible tether allows each satellite to move independently within a certain range without transmitting mechanical forces to neighboring satellites, thereby maintaining both physical connection and independent movement capability while preserving FSO link stability.
Solution Approach 2:
The loose tether design provides a cushioning effect that absorbs relative movements between satellites before they can affect the FSO communication links. This beforehand cushioning prevents the transmission of disruptive forces that would otherwise degrade link reliability, allowing independent satellite operations.
4Productivity
If omni-directional RF links or wide-beam free-space optical links are used for multi-satellite communication, then full communication ability between satellites is achieved, but the data rate is limited
Solution Approach 1:
The system merges the advantages of directional high-data-rate FSO links with the flexibility of multi-satellite connectivity. By using narrow-beam FSO links combined with independent satellite body steering, the system achieves both high data rates and the ability to establish multiple communication paths, effectively combining the benefits previously available only through complex omni-directional or wide-beam configurations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The loose optical fiber tether system provides reliable, high data rate communications between satellites by maintaining accurate steering angles and allowing independent satellite movement, overcoming the limitations of traditional alignment methods and omni-directional RF links, while also enabling power transfer and maintaining satellite proximity.
Implementation Method 1
a tether including an optical fiber having first and second ends, wherein the first end is connected to the first satellite and the second end is connected to the second satellite
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A multi-satellite system includes a first satellite and a second satellite configured to be separated in a predetermined distance between the satellites after being launched into space, and a tether including an optical fiber having first and second ends, wherein the first end is connected to the first satellite and the second end is connected to the second satellite, wherein a length of the tether is greater than the predetermined distance. In this case, the first satellite includes an optical transceiver connected to the first end of the optical fiber to provide a communications link to the second satellite, a spool containing partial winding of the tether, and a free space optical transceiver to provide a first communications link to a first distant satellite. Further, the second satellite includes an optical transceiver connected to the second end of the optical fiber to provide the communications link to the first satellite, and a spool containing partial winding of the tether, and a free space optical transceiver to provide a second communications link to a second distant satellite.