Target mass

The target mass is a critical parameter in the development and design of space systems. It is used to ensure that the final weight of a system remains within the permissible limits. The target mass is determined by both a top-down and bottom-up approach to ensure that the system can be operated safely and efficiently.

Top-down total target mass

The top-down total target mass is usually a percentage value less than the permissible mass or weight that must not be exceeded (NTEW - Not To Exceed Weight). This target mass is defined at the beginning of a project and serves as a guideline for the entire design and development:

Project requirements: The top-down total target mass is determined based on the project requirements and specifications. It ensures that the system meets the performance and safety requirements.
Phase dependence: The top-down total target mass can vary from phase to phase, as the requirements and specifications can change over the course of the project.

Bottom-up target mass

The target mass of the component is derived using a bottom-up approach. This approach takes into account the projected mass of the individual components and systems, including the associated risks and opportunities:

Predicted mass: The predicted mass includes the estimated mass of all components and systems based on designs, materials and manufacturing processes.
Risks and opportunities: When calculating the bottom-up target mass, risks and opportunities that can influence the mass are taken into account. Risks can lead to an increase in mass, while opportunities can enable a reduction in mass.
Adjustment: The bottom-up target mass is compared with the top-down total target mass to ensure that the system weight remains safely below the permissible mass.

Significance of the target mass

The target mass is of great importance for the planning and implementation of space projects:

Security: Compliance with the target mass ensures that the system can be operated safely and meets the requirements.
Performance: The target mass influences the performance of the system, as the weight is directly related to efficiency and operating costs.
Cost management: By adhering to the target mass, the costs of the project can be controlled and optimized, as excess weight can lead to additional costs.

Measures to meet the target mass

Various measures can be taken to ensure that the target mass is met:

Design optimization: Optimization of the design to reduce mass and increase efficiency.
Material selection: Selection of lightweight and high-strength materials to minimize mass.
Risk management: Implementation of risk management strategies to identify and minimize potential mass overruns.
Regular checks: Carry out regular reviews and adjustments to ensure that the target mass is maintained throughout the project.

Summary