# New Space Engineering Design: Characterization of Key Drivers
## 3 Results and Discussion
### General Discussion of New Space Design Drivers and Enablers
#### 3.1.3 Category C: Sustainability and Technological Independence  
A growing awareness of sustainability and safety on Earth is fostering a parallel consciousness in the space sector, encouraging the adoption of more sustainable practices beyond our planet. As a result, mission designers and, consequently, system and subsystem engineers, are expected to integrate space debris mitigation measures from the early development stages in response to the impending issue of debris accumulation in LEO. For satellites in low orbits, especially larger ones with multiple components that are more likely to survive the harsh conditions of reentry, fast or fully controlled deorbiting maneuvers are preferred to minimize risks to human life and ground infrastructure [50]. These maneuvers ensure reentry over designated uninhabited regions, typically the South Pacific Ocean. In contrast, for satellites in Geosynchronous Equatorial Orbit (GEO), the standard EOL strategy is re-orbiting the spacecraft into a designated disposal orbit, commonly known as a \"graveyard orbit\", to minimize consumption and risk in the operational GEO belt [51]. However, this solution might soon be reconsidered due to long-term sustainability concerns about the accumulation of inactive objects in distant orbital regions. To minimize the cost of additional fuel or the need for propulsion capability, uncontrolled atmospheric reentry is often permitted, especially for small satellites, provided the estimated risk of human casualty remains below internationally accepted limits (i.e., 1 in 10,000) [52]. This requires that the object reenters naturally within 25 years after the end of its mission. Yet due to the limited global enforcement of these voluntary guidelines, the increasing number of LEO launches, and the resulting increased risk of in-orbit collisions, this approach is also being re-evaluated [53; 54; 55]. Alternative strategies for planning safe satellite disposal, such as replacing the demanding full controlled reentry, can still significantly reduce the risk of harmful impacts. Hybrid solutions, such as assisted natural reentry, have been proposed as a compromise between cost and safety for medium-class satellites [56]. Other approaches include designing for reusability (as in some launcher systems [57]) or implementing Design for Demise strategies [58]. These involve selecting materials with low survivability (e.g., those with a low melting point), optimizing structural components for controlled breakup, and strategically configuring and placing hardware to ensure predictable disintegration [59; 60]. These design choices can be introduced early in the development process. While they may involve performance tradeoffs that complicate system design, they offer long-term benefits for forward-looking companies, particularly as guidelines on spacecraft Post-Mission Disposal (PMD) become more stringent, and compliance may soon become mandatory in some mission scenarios given the evolving regulatory landscape [10; 11; 61]. Tools such as DRAMA (Debris Risk Assessment and Mitigation Analysis) by the European Space Agency (ESA) and DAS (Debris Assessment Software) by the National Aeronautics and Space Administration (NASA) are available to assess compliance with international standards during mission planning. Notably, the Indian Space Research Organization (ISRO) is also active in this field. It has launched an initiative for orbital debris monitoring and prediction called Project NETRA (Network for space object TRacking and Analysis). In addition to debris mitigation, active collision avoidance is becoming a critical requirement. This capability is essential to prevent collisions with large objects, which could not only generate new debris but also lead to complete mission failure. Collision avoidance maneuvers are feasible only for spacecraft equipped with active propulsion systems, designed with sufficient performance and extra propellant storage.