Sam Wagner

Analysis and Design of Fictive Post-2029 Apophis Intercept Mission for Nuclear Disruption

An impact from asteroid 99942 Apophis now seems unlikely (with an impact probability of approximately four-in-a million). However, in this paper it will be assumed that Apophis passes through a keyhole in 2029 and is inserted into a resonant orbit that will result in an impact on April 13th, 2036. Launch dates utilizing an Interplanetary Ballistic Missile system, capable of carrying up to a 1500 kg nuclear payload, and a total V of 4 km/s are determined. Mission analysis for the 0-revolution rendezvous and intercept mission is performed as well as multiple revolution missions and more complicated mission designs which allow for rendezvous missions to be launched after the last feasible short 0-revolution rendezvous case. In this study it is assumed that for a subsurface nuclear explosion Apophis must be intercepted at least 15 days prior to Earth impact on April 13th, 2036. It is also assumed that if Apophis passes through the keyhole in 2029 a high energy nuclear deflection mission will be required to ensure Apophis doesn’t impact the Earth. Nomenclature a

Analysis and Selection of Optimal Targets for a Planetary Defense Technology Demonstration Mission

of blending a hypervelocity kinetic impactor with a penetrated nuclear subsurface explosion. Possible asteroid candidates are found by determining optimal missions for several possible mission architectures for nearly 3400 potential asteroids. The optimization is performed using a genetic algorithm developed to solve complex mission design problems.

GPU Accelerated Genetic Algorithm for Multiple Gravity-Assist and Impulsive V Maneuvers

A combination of multiple gravity-assist and impulsive V maneuvers are often utilized for interplanetary missions to outer planets, such as NASA’s Galileo and Cassini missions. Such complex interplanetary missions often require the optimization of more than 20 variables, making brute force and traditional NLP methods dicult, if not impossible. In this paper a genetic algorithm, which utilizes the computational power of modern GPUs, is developed to solve the problem of designing advanced mission. By using modern GPUs the computational burden for advanced mission designs can be drastically reduced over traditional CPU optimization programs, allowing the mission designer to explore multiple mission scenarios or other mission options.

Hybrid Algorithm for Multiple Gravity-Assist and Impulsive Delta-V Maneuvers

A combination of multiple gravity-assist and impulsive Delta-V maneuvers is often required for interplanetary and interstellar space missions, such as NASA’s Voyager 1 and 2, Galileo, and Cassini missions. The design of such complex interplanetary missions is difficult with traditional mission analysis techniques because the mission must be prepruned to determine potential trajectories. Prepruning has been necessary because these mission often require the optimization of dozens of variables in a highly nonlinear and discontinuous design space. This process risks pruning nonintuitive solutions, which may potentially contain the optimal trajectory. In this paper, a hybrid optimization algorithm that is capable of determining optimal interplanetary trajectories, including the number of gravity assists and the planetary flyby order, is developed. The hybrid optimization algorithm uses a stochastic genetic algorithm to globally search the design space, as well as traditional nonlinear programming gradient-base...

Preliminary Design of a Crewed Mission to Asteroid Apophis in 2029-2036

A crewed mission to a near-Earth object (NEO) as early as 2025 was announced by President Obama on April 15th, 2010 at the Kennedy Space Center in Florida. This was announced as part of NASA’s new space exploration plan after announcing plans to cancel the Constellation program. The extensive requirements of such a mission would help NASA to evaluate the performance of future space systems prior to sending a crewed mission to Mars. Apophis, an asteroid of particular interest due to its once high impact probability, would be a logical choice for a manned mission in the near future. This mission could provide a valuable NEO research opportunity to determine the composition of Apophis. This data that would be extremely useful if Apophis were to pass through the gravitational keyhole in 2029, which would then require a deflection mission. This paper focuses on mission design as well as the system architecture that would be required for this mission to Apophis. The primary mission will be a 180 day mission in the 2028-2029 range during the Earth-Apophis close encounter on April 13th, 2029. In an effort to reduce mission requirements mission analysis for missions up to 1 year will be performed as well. In this paper a crewed mission will be designed for a fictional scenario where Apophis has gone through the 2029 keyhole, which puts it on a resonant orbit that will collide with the earth on April 13th, 2036. This work provides baseline mission requirements and optimum launch windows and trajectories for the crewed mission to Apophis, as well as possible mission architecture that allow such missions.

The First Human Asteroid Mission: Target Selection and Conceptual Mission Design

President Obama has recently declared that NASA will pursue a crewed mission to an asteroid by 2025. This paper identifies the optimum target candidates of near-Earth objects (NEOs) for a first crewed mission between 2018 and 2030. Target asteroids in the NEO database with orbital elements that meet predetermined requirements are analyzed for mission design. System architectures are then proposed to meet the requirements for five designated NEO candidates. Additional technology which can be applied to crewed NEO missions in the future is also discussed, and a previous NEO target selection study is analyzed. Although some development of heavy launch vehicles is still required for the first NEO mission, design examples show that a first mission can be achieved by 2025. The Ares V and the Orion CEV are used as the baseline system architecture for this study.