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NewMars members are working on design of several kinds of spacecraft that would provide artificial gravity.
Some designs use dual rotating structures to prevent gyroscopic effects from interfering with navigation.
The original Large Ship of RobertDyck was a Unitary design, and the Baton design of GW Johnson would rotate on it's own as well.
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In hopes of setting the stage for study of Precession as an issue to be addressed, I asked ChatGPT4o to set up a conversation of the topic.
Discussion on Managing Precession for Rotating Space Habitats
Below is a formatted discussion between myself and ChatGPT on the challenge of precession in a rotating space vessel designed for artificial gravity. This conversation is shared for collaborative exploration and feedback.
User's Inquiry
I am working with a small group that is thinking about the problem of protecting humans traveling in space. There are many solutions on offer, but the least expensive and the easiest to implement appears to be a cylinder that would rotate in space like a baton used by a cheerleader on Earth.
The proposal is to secure a number of cylindrical habitats end to end, so that the entire structure can rotate end over end to provide sufficient artificial gravity for good health. We have determined a safe rate of rotation, based upon research, so please don't spend any time on that. The issue at hand is how the baton will behave after it has been set in rotation.
The space vessel is to be fitted with solar panels that must be kept perpendicular to the Sun. I am worried about how precession might cause the rotation to depart from the initial state. Precession may not be something you have been asked to consider before now, so I will understand if you decide to suggest some references to study.
ChatGPT's Response
Thank you for the detailed description of the problem—it’s an intriguing engineering challenge and an essential one for ensuring the safety and effectiveness of human space travel. Precession in a rotating system like the one you described is indeed a critical consideration, particularly when you need to maintain specific orientations for solar panels relative to the Sun.
Understanding the Problem
[]Structure: A rotating baton-like assembly of cylindrical habitats. []Purpose of Rotation: To generate artificial gravity for human health. []Solar Panels: Must remain perpendicular to the Sun, requiring orientation control. []Potential Issue: Precession may cause the rotational axis to drift, affecting the alignment of the solar panels and the stability of the structure.
Precession in Rotating Systems
Precession occurs when a torque is applied to a rotating object, causing its rotational axis to shift. This can arise from:
[]External forces: Gravitational interactions, solar radiation pressure, or micrometeoroid impacts. []Internal dynamics: Uneven mass distribution or gyroscopic coupling between segments of the structure.
Strategies to Address Precession
[]Active Stabilization [ul] []Reaction Wheels or Control Moment Gyroscopes (CMGs): Use angular momentum to adjust and stabilize the orientation. Advantages: High precision, continuous control.
Challenges: Requires electrical power.Thruster-Based Control: Periodically counteract drift with attitude-control thrusters.
Advantages: No moving parts; simplicity.
Challenges: Consumes propellant. [/ul]Structural Symmetry and Balancing
Ensure the habitats and connected components (e.g., solar panels) are as symmetrical and dynamically balanced as possible. Use counterweights if needed.Gyroscopic Effects of Rotating Habitats
Habitats act as gyroscopes, resisting orientation changes. However, this introduces gyroscopic coupling, potentially creating complex oscillatory motion.Magnetic or Electrostatic Tethers
A long tether could stabilize the rotational axis by damping precession via interaction with Earth's magnetic field or internal energy dissipation.Solar Panel Articulation
Allow solar panels to adjust independently of the main body.
Advantages: Ensures maximum solar efficiency.
Challenges: Adds mechanical complexity.Analysis and Simulation
[]Numerical Modeling: Use tools like MATLAB, Simulink, or Python libraries (e.g., NumPy, SciPy) to simulate precession and evaluate stabilization strategies. []Finite Element Analysis (FEA): Model the structural dynamics of the rotating system, especially if it has flexible connections.
Testing in Microgravity: Small-scale prototypes could be tested on the International Space Station (ISS) or in parabolic flight.
Conclusion
Precession is a manageable challenge if considered during the design phase. Strategies like active stabilization, structural balancing, and independent solar panel articulation can effectively mitigate its effects. Moving forward, your group might prioritize:
[]Building a detailed simulation of rotational dynamics. []Exploring control technologies like CMGs or reaction wheels.
Considering modular solar panels with independent adjustment.
If additional details or conceptual simulations are needed, feel free to reach out!
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There is a phenomenon called "chaotic rotation" that is observed in certain asteroids...
I am concerned that the Baton spacecraft design that looks attractive from a number of points of view, may be subject to chaotic rotation, because it has an elongated shape and because mass can (and most certainly will) move around inside the vessel.
I asked Google to see what it could find, and here is what it came up with:
chaotic rotation of asteroid
A "chaotic rotation of an asteroid" refers to an irregular and unpredictable spinning motion of an asteroid, where its rotation axis can change significantly over time due to its uneven shape and gravitational interactions with other celestial bodies, causing it to tumble erratically instead of rotating smoothly on a fixed axis; this phenomenon is most prevalent in asteroids with elongated or oddly shaped bodies and occurs when the gravitational forces acting on them become complex and sensitive to initial conditions.
Key points about chaotic rotation of asteroids:
Cause:
The primary reason for chaotic rotation is the non-uniform distribution of mass within an asteroid, often caused by its irregular shape, which leads to uneven gravitational torques acting on it as it orbits.Shape matters:
Asteroids with large bulges or significant elongation along one axis are more prone to chaotic rotation compared to near-spherical ones.Gravitational influences:
The gravitational pull from other celestial bodies, particularly planets like Jupiter, can also contribute to chaotic rotation by causing perturbations in the asteroid's orbit and rotation.
Detecting chaos:
Astronomers use sophisticated numerical models to analyze an asteroid's light curve (brightness variations as it rotates) to identify signs of chaotic rotation.Chaos over order: mapping 3D rotation of triaxial asteroids and minor planets | Monthly Notices of the Royal Astronomical Society | Oxford Academic
Oxford AcademicChaotic rotation - Wikipedia
Chaotic rotation involves the irregular and unpredictable rotation of an astronomical body. ... Because of the conservation of ang...
Wikipedia
mapping 3D rotation of triaxial asteroids and minor planets
Apr 18, 2022 — Celestial bodies approximated with rigid triaxial ellipsoids in a two-body system can rotate chaotically due to the ti...
Oxford Academic
In a Baton ship carrying crew from Earth to Mars (or anywhere) the center of mass will move as the crew go about their daily lives. The rotation of the ship is about it's center of mass. My guess is that as crew and liquids and other materials are moved about in the two sides of the rotating vessel, the center of mass will move, and that will cause the forces at work in the rotation to interact with the masses.
The argument has been offered that the mass of crew and liquids and supplies that might move would be significantly less than the mass of the ship itself.
My concern is that even small mass imbalance will be noticeable.
At the moment (to the best of my knowledge) this forum does not include a registered member who has access to computing hardware and software capable of modeling the behavior of a Baton Spaceship in flight between Earth and Mars.
The Internet has many examples of animation showing moving masses, but none I have found so far appear to match the problem this topic is set up to consider.
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