Consumable Transfer Controller

Description

The Consumable Transfer Controller manages the transfer of consumable mass between two linked mass storage containers. It monitors the source and destination storage states and regulates the flow rate based on availability and capacity constraints. The controller supports an optional physical link requirement, ensuring that transfers only occur between containers on the same spacecraft or between docked spacecraft.

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Example Use Cases

• Propellant Transfer: Transfer fuel or oxidizer between tanks during on-orbit refueling operations.
• Consumable Redistribution: Balance consumables between storage containers within a spacecraft.
• Docked Operations: Enable resource sharing between docked spacecraft during rendezvous missions.

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Module Implementation

Transfer Rate Calculation

At each simulation step, the controller computes the actual transfer rate based on three constraints: the desired transfer rate, the available mass in the source container, and the remaining capacity in the destination container.

The available mass for transfer during a time step $\Delta t$ is:

$$m_{\text{available}}=\min \left(m_{\text{source}},{\dot{m}}_{\text{desired}}\cdot \Delta t\right)$$

where $m_{\text{source}}$ is the current payload mass in the source container and ${\dot{m}}_{\text{desired}}$ is the desired transfer rate in kg/s.

The free capacity in the destination container is:

$$m_{\text{free}}=C_{\text{dest}}-m_{\text{dest}}$$

where $C_{\text{dest}}$ is the destination container capacity and $m_{\text{dest}}$ is its current payload mass.

The actual mass transferred per step is then:

$$\Delta m=\min \left(m_{\text{available}},\max (0,m_{\text{free}})\right)$$

The actual transfer rate is computed as:

$${\dot{m}}_{\text{actual}}=\frac{\Delta m}{\Delta t}$$

Physical Link Requirement

When the physical link requirement is enabled, the controller verifies that a valid connection exists between the source and destination storage containers before allowing transfer. A transfer is permitted when either:

1. Both storage containers belong to the same root spacecraft.
2. The root spacecraft of each container are docked to one another.

If neither condition is satisfied, the transfer rate is set to zero regardless of other parameters.

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Assumptions/Limitations

• The controller operates on linked mass storage status messages; it does not directly access the storage containers.
• Transfer is instantaneous within each time step once constraints are satisfied.
• The physical link check uses spacecraft docking state and does not model intermediate transfer hardware such as hoses or pumps.
• Mass conservation is enforced; the mass removed from the source equals the mass added to the destination.
• The controller does not model thermal effects, pressure differentials, or transfer efficiency losses.