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Cluster flight is defined as the operation of multiple cooperative satellites under minimum and maximum distance constraints. Unlike traditional orbit injection of multiple noncooperative satellites, judicious constraints should be imposed on the orbit injection of a cluster. Moreover, the orbital injection should enable a fuel-efficient cluster establishment maneuver. This study develops constraints for the orbit injection of a satellite cluster. Evaluation of feasible orbit injection scenarios is performed. Particular launch vehicles and a concomitant set of orbital injection scenarios are found, which are the most suitable for long-term operation of a cluster. In addition, an efficient cluster establishment control method is developed, which prevents the cluster from drifting apart too rapidly. Several orbit injection scenarios are simulated and their feasibility for a planned cluster flight mission is evaluated. It is shown that both the Polar Satellite Launch Vehicle and the Dnepr launcher can be use...

The Mars Science Laboratory Entry, Descent, and Landing systems engineering team was presented with many challenges in its verification and validation campaign. These challenges arose from both the general complexity of the system architecture and the schedule and resource limitations of the test program. As a result, the team had to accommodate a complex set of requirements, test venues, test objectives, and analysis products. Discussed within are logistical problems faced by the team related to managing these complexities in a portion of Entry, Descent, and Landing verification and validation scope known as the flight system domain. The flight system domain encompassed software–software interactions and system-level software–hardware interactions that happened during the Entry, Descent, and Landing phase of the mission and necessitated the use of flight software and/or flight-equivalent hardware for final verification. The following application-specific solutions were developed to mitigate the complexit...

An analysis of the longitudinal aerodynamics of the shuttle orbiter in the hypersonic flight regime is made through the use of computational fluid dynamics. Particular attention is given to establishing the cause of the 'pitching moment anomaly,' which occurred on the orbiter's first flight, and to computing the aerodynamics of a complete orbiter configuration at flight conditions. Data from ground-based facilities as well as orbiter flight data are used to validate the computed results. Analysis shows that the pitching moment anomaly is a real-gas chemistry effect that was not simulated in ground-based facilities, which used air as a test gas. Computed flight aerodynamics for the orbiter are within 5% of the measured flight values and trim bodyflap deflections are predicted to within 10%.

Hydraulic support system for free flight simulation with Saturn V-Apollo vehicle, discussing stability requirements, upper bounds of system design, conversion from nonlinear to linear model, etc