Taylor Hampson, a master's student at MIT's Department of Nuclear Science and Engineering (NSE), is conducting NASA-sponsored research focused on modeling nuclear thermal propulsion (NTP) systems. This work aims to address the propulsion challenges inherent in future human missions to Mars, a planet significantly farther from Earth than the moon. NTP offers potential advantages in efficiency and travel time compared to current chemical rockets.
Challenges of Mars Missions and Propulsion Needs
Traveling to Mars presents considerable challenges due to its vast distance, which fluctuates between approximately 33 million and 249 million miles. This distance substantially exceeds the moon's average distance of 238,855 miles. Current propulsion systems utilized for lunar missions are deemed insufficient for the requirements of crewed Mars missions. NASA has indicated plans for human missions to Mars as early as the 2030s, necessitating the development of more advanced propulsion technologies.
Nuclear Thermal Propulsion Overview
Nuclear Thermal Propulsion (NTP) is a propulsion method under investigation for deep-space travel. It operates by utilizing nuclear energy to heat a propellant, such as liquid hydrogen, to extremely high temperatures. The superheated propellant is then expelled through a nozzle, generating thrust. NTP systems are projected to offer double or more efficiency compared to conventional chemical rockets, which could significantly reduce travel times to Mars. Shorter travel durations are considered beneficial for astronauts, potentially mitigating the effects of prolonged exposure to microgravity.
Rocket propulsion systems are generally categorized into three types:
- Chemical propulsion: Generates thrust through the combustion of propellants.
- Electrical propulsion: Uses electric fields to accelerate charged particles for thrust.
- Nuclear propulsion: Employs nuclear energy for thrust. This category includes nuclear electric propulsion (generating electricity to accelerate propellant) and nuclear thermal propulsion (heating propellant with nuclear power).
Historically, the primary challenges associated with NTP have included higher development costs and complex regulatory frameworks. Additionally, the absence of a mission profile demanding NTP's level of efficiency has been a factor. However, with NASA's future Mars mission objectives, the viability of NTP is gaining increased attention.
Taylor Hampson's Research at MIT
Taylor Hampson's NASA-sponsored research at MIT, advised by Associate Professor Koroush Shirvan, continues a project initiated during an internship at NASA. His work focuses on creating models of the entire NTP rocket engine system, including components such as the tank and pump. This comprehensive modeling aims to understand the interactions between various operational parameters and how different configurations of parts and fuel might influence performance.
Hampson employs a simplified one-dimensional model to expedite simulations, allowing for the tracking of variables like temperature and pressure across different engine components. A key aspect of this research involves effectively coupling thermodynamic effects with neutronic effects within the engine's design.
Operational Considerations for NTP Engines
The operation of NTP engines involves specific complexities. Unlike some combustion engines, NTP systems do not start and shut down rapidly.
- Startup: Rapid temperature increases during the startup phase can potentially lead to material failures within the engine components.
- Shutdown: The shutdown process takes a longer duration due to residual heat generated from nuclear decay. Components require continuous cooling until sufficient fission products have decayed, and the residual heat levels decrease.