Spacecraft Stack Deployment Using Threaded Rods
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Solution Overview
Problem
Current spacecraft deployment systems, such as the EELV-ESPA, are inefficient in volume and weight, leading to significant waste and structural instability during launch, and lack effective deployment control, resulting in potential collisions and tumbling of spacecraft.
Innovation Solution
A system utilizing a baseplate with orthogonal threaded rods and coupling mechanisms that allow spacecraft to be stacked and deployed efficiently, with preloading to stabilize the stack and precise control over deployment velocity, and also enables retrieval of spacecraft to reduce space junk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple spacecraft are launched using the ESPA adapter system, then multiple payloads can be deployed from a single launch vehicle, but volume efficiency is significantly reduced due to wasted space between vehicles and fairing
Solution Approach 1:
The patent implements a nested configuration where spacecraft are stacked vertically one above another in a compact arrangement, with each spacecraft positioned within the envelope of the launch vehicle. This nesting approach eliminates the lateral spacing required by ESPA adapters, achieving volume efficiency exceeding 95% by utilizing the full payload envelope from bottom to top.
Solution Approach 2:
The patent transitions from the horizontal arrangement of ESPA adapters to a vertical stacking configuration. By arranging spacecraft in the vertical dimension rather than horizontal planes, the system maximizes the use of available payload volume while maintaining structural integrity and load path efficiency.
2Quantity of substance
If the ESPA adapter is designed to support multiple spacecraft, then multiple payloads can be accommodated, but the adapter weight increases to 400-600 pounds
Solution Approach 1:
The patent divides the support structure into individual coupling mechanisms for each spacecraft rather than using a single heavy adapter. Each spacecraft is independently coupled to the launch vehicle or to another spacecraft, distributing the support function across multiple lightweight coupling points and eliminating the need for a massive central adapter structure.
Solution Approach 2:
The patent extracts the adapter function from a separate heavy component and integrates it directly into the spacecraft structures themselves. Each spacecraft includes its own coupling mechanism, eliminating the need for a dedicated 400-600 pound adapter and reducing overall system mass.
3Quantity of substance
If the ESPA adapter supports multiple spacecraft, then multi-payload deployment is enabled, but the fairing weight exceeds 1000 pounds
Solution Approach 1:
The patent uses a compact vertical nesting arrangement that allows spacecraft to be tightly packed within a smaller fairing envelope. This eliminates the need for a large 1000+ pound fairing by reducing the overall volume required to protect the payload stack during ascent.
4Ease of operation
If spacecraft are deployed by releasing the coupling after fairing release, then deployment is simple, but the spacecraft tumble away without controlled deployment
Solution Approach 1:
The patent employs dynamic coupling mechanisms that can be actively controlled to deploy spacecraft at specific points along the trajectory. Rather than simple release, the coupling mechanisms incorporate actuators that enable controlled separation velocity and timing, allowing spacecraft to deploy in a controlled manner rather than tumbling away.
Solution Approach 2:
The patent implements feedback control systems that monitor launch vehicle position, velocity, and orientation to determine the optimal deployment moment. This feedback enables the coupling mechanism to release at the precise moment when deployment conditions are optimal, ensuring controlled spacecraft separation rather than uncontrolled tumbling.
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
This solution enhances volume efficiency, reduces mass overhead, minimizes deflections, and provides controlled deployment and retrieval of spacecraft, improving launch stability and reducing space debris.
Implementation Method 1
A plurality of threaded rods are arranged orthogonal to a surface of the baseplate... Each spacecraft includes a coupling mechanism that selectively engages or disengages each threaded rod... when the threaded rods are rotated, the spacecraft travels along the threaded rods
Implementation Method 2
a spring mechanism in each coupling device propels the top-most satellite away from the stack
Data Source
AI summary
A system and method for installing, deploying, and recovering a plurality of spacecraft that provides an ease of use and structural stability, and facilitates a standardization of spacecraft design. In embodiments of this invention, threaded rods are arranged orthogonal to a surface of a baseplate, and each spacecraft includes a coupling mechanism that selectively engages or disengages each threaded rod. Each spacecraft is added to the stack by engaging its coupling mechanism and rotating the threaded rods while the preceding spacecraft on the stack disengage their coupling mechanisms, thereby enabling the spacecraft to travel along the threaded rods toward the baseplate. When all of the spacecraft are added to the stack, the stack is preloaded by rotating the treaded rods into a terminator component at the top of the stack while the coupling mechanisms in all of the spacecraft are disengaged. Spacecraft are deployed by reversing the process.