Manned missions to Mars: Minimizing risks of failure

AIAA SPACE 2016, 2016

Space Administration (NASA) continues to evaluate potential approaches for sending humans beyond low Earth orbit (LEO). A key aspect of these missions is the strategy that is employed to maintain and repair the spacecraft systems, ensuring that they continue to function and support the crew. Long duration missions beyond LEO present unique and severe maintainability challenges due to a variety of factors, including: limited to no opportunities for resupply, the distance from Earth, mass and volume constraints of spacecraft, high sensitivity of transportation element designs to variation in mass, the lack of abort opportunities to Earth, limited hardware heritage information, and the operation of human-rated systems in a radiation environment with little to no experience. The current approach to maintainability, as implemented on ISS, which includes a large number of spares pre-positioned on ISS, a larger supply sitting on Earth waiting to be flown to ISS, and an on demand delivery of logistics from Earth, is not feasible for future deep space human missions. For missions beyond LEO, significant modifications to the maintainability approach will be required.

69th International Astronautical Congress (IAC), 2018

Mars missions can be seen as a natural step in space exploration, as Earth-like environmental conditions and the length of the interplanetary flight are the most crucial for planetary exploration compared to other celestial bodies of the Solar System. On the other hand, these missions require detailed planning and worldwide collaboration, because of the need of extremely high financial resources and technical capabilities. Many researches focused on different aspects of Mars missions are being conducted in these recent years. They include flight preparation, lift-off, interplanetary journey, habitat and Life Support Systems (LSS) design, Extravehicular Activities (EVA), precise landing, planetary exploration, etc. This paper summarizes identified safety issues that can arise during future Mars missions. Based on the analysis of previous studies, where conditions of the interplanetary flight were studied, including environmental issues, Mars habitat and the spacecraft design were discussed and the spacesuit concept was analyzed, the most critical hazards have been defined and the whole mission has been taken into consideration. In particular, possible failures and hazards for the habitat on Mars, space station and spacesuit, including off-nominal situations and their influence on the safety of the astronauts have been investigated. This work is based on the results of previous projects carried out within the Space Generation Advisory Council's (SGAC) Space Safety and Sustainability project group, which aims to bring an international and interdisciplinary vision to this topic and discuss it from different perspectives, creating a foundation for further studies on safety risk assessment. Technological gaps are identified for further discussion and possible solutions for risks reduction are proposed with regard to onboard systems (including LSS) and layout design.

2006

1 Abstract This paper will discuss the Probabilistic Risk Assessment (PRA) effort and its involvement with related activities during the development of the Mars Exploration Rover (MER). The Rovers were launched 2003.June.10 (Spirit) and 2003.July.7 (Opportunity), and both have proven very successful. Although designed for a 90-day mission, the Rovers have been operating for over two earth years. This paper will review aspects of how the MER project integrated PRA into the design and development process. A companion paper (Development ofthe Mars ExpIoration Rover PRA) will describe the MER PRA and design changes fiom those results.

International Journal of Human Factors Modelling and Simulation

Long duration and complex mission scenarios are characteristics of NASA's human exploration of Mars, and will provide unprecedented challenges. Systems reliability and safety will become increasingly demanding and management of uncertainty will be increasingly important. NASA's current pioneering strategy recognizes and relies upon assurance of crew and asset safety. In this regard, flexibility to develop and innovate in the emergence of new design environments and methodologies, encompassing modeling of complex systems, is essential to meet the challenges.

AIAA Space 2003 Conference & Exposition, 2003

This paper presents an approach and corresponding tool to assess and analyze the risks involved in a mission during the pre-phase A design process. This approach is based on creating a risk template for each subsystem expert involved in the mission design process and defining appropriate interactions between the templates. A separate "risk expert" mediates this process and incorporates the information obtained by the various subsystems to produce a report that reflects the weak links of the mission, the major risk elements for each phase, and the overall risk measure.

Acta Astronautica, 2004

Discussions of future human expeditions into the solar system generally focus on whether the next explorers ought to go to the Moon or to Mars. The only mission scenario developed in any detail within NASA is an expedition to Mars with a 500-day stay at the surface. The technological capabilities and the operational experience base required for such a mission do not now exist nor has any self-consistent program plan been proposed to acquire them. Planning for mission operations without having an experience base with similar missions has significant risk. As has been previously argued, a wellplanned program of human exploration of the Moon would provide a context within which to develop the appropriate capabilities because a lunar expedition contains many of the operational elements of a Mars expedition. Initial lunar expeditions can be carried out at scales consistent with the current experience base but can be expanded in any or all operational phases to produce an experience base necessary to successfully and safely conduct human exploration of Mars.

2013 IEEE Aerospace Conference, 2013

NASA's long-range goal is focused upon human exploration of Mars. Missions to Mars will require campaigns of multiple launches to assemble Mars Transfer Vehicles in Earth orbit. Launch campaigns are subject to delays, launch vehicles can fail to place their payloads into the required orbit, and spacecraft may fail during the assembly process or while loitering prior to the Trans-Mars Injection (TMI) burn. Additionally, missions to Mars have constrained departure windows lasting approximately sixty days that repeat approximately every two years. Ensuring high reliability of launching and assembling all required elements in time to support the TMI window will be a key enabler to mission success. This paper describes an integrated methodology for analyzing and improving the reliability of the launch and assembly campaign phase. A discrete event simulation involves several pertinent risk factors including, but not limited to: manufacturing completion; transportation; ground processing; launch countdown; ascent; rendezvous and docking, assembly, and orbital operations leading up to TMI. The model accommodates varying numbers of launches, including the potential for spare launches. Having a spare launch capability provides significant improvement to mission success.

2005

2013 Proceedings Annual Reliability and Maintainability Symposium (RAMS), 2013

A risk analysis of the launch, orbital assembly, and Earthdeparture phases of human Mars exploration campaign architectures was completed as an extension of a probabilistic risk assessment (PRA) originally carried out under the NASA Constellation Program Ares V Project [1]. The objective of the updated analysis was to study the sensitivity of loss-ofcampaign risk to such architectural factors as composition of the propellant delivery portion of the launch vehicle fleet (Ares V heavy-lift launch vehicle vs. smaller/cheaper commercial launchers) and the degree of launcher or Mars-bound spacecraft element sparing. Both a static PRA analysis and a dynamic, event-based Monte Carlo simulation were developed and used to evaluate the probability of loss of campaign under different sparing options. Results showed that with no sparing, loss-of-campaign risk is strongly driven by launcher count and on-orbit loiter duration, favoring an all-Ares V launch approach. Further, the reliability of the all-Ares V architecture showed significant improvement with the addition of a single spare launcher/payload. Among architectures utilizing a mix of Ares V and commercial launchers, those that minimized the on-orbit loiter duration of Mars-bound elements were found to exceed the reliability of no spare all-Ares V campaign if unlimited commercial vehicle sparing was assumed.