Introduction
Designing a manned mission to Mars is obviously an extremely complex task, and one that requires knowledge on various disciplines. Trajectories have to be calculated, rockets designed and selected, life support systems integrated into the spacecraft to provide nourishment and a survivable environment to the astronauts that will be selected to make the journey.
Real life solutions to all these problems exceed the scope of the Mars Academy project, which is intended to high school/college students and the general public. However, in our mission design we will use existing and foreseeable technology (for example, the existence of the International Space Station) to approximate and integrate solutions to all the design problems into a Mars mission. After a complete plan for the journey is put together, a web based simulation of the mission based on the adopted solutions will be run.
Mission goals
The first step in the design of any mission is the setting of goals. These goals help to define the mission more precisely in terms of objectives that will be met and assist the mission planners in the design process.
Whenever a scientific or operational decision needs to be made, the goals will be referenced and strictly adhered to in order to include experiments and instruments, lay out a mission sequence, select the crew members based on their training and expertise, always prioritizing those activities that lead to the completion and meeting of the mission goals.
The mission itself, the type of spacecraft and the duration of the trip will result from the setting of the goals and not the other way round.
Mission goals are so important that they are chosen at top management areas, being a high level decision. Primary mission goals are often decided prior to the design of the mission and do not require an extensive technical knowledge. For example, in our case, a primary goal that everybody would agree upon would be that the crew should be transported to Mars and return safely to Earth. Setting such a goal does not require an in depth technical knowledge and can thus be passed on by non-technical management staff.
Other primary or secondary goals are more scientific in nature and depend on available hardware and should not be set unrealistically. For example, bringing back samples in an unmanned mission involves a major design issue and should not be decided without a careful and detailed study of the technical factors that are involved in the decision.
In order to define the mission goals, Mars Academy members have voted a number of mission goals after email and web chat consultations.
Landing site
The logical order of decisions then involves selecting a landing site in accordance to the mission goals. There is an extensive online collection of Mars related sites that contain pictures and descriptions of possible landing sites
Mars Academy members held a web chat to decide on the landing site. Another web chat was held with Dr. Jim Bell, a planetary scientist from Cornell University.
Crew selection
The issue of crew selection is closely related to the mission goals in that the crewmember chosen must be able to perform all mission activities that lead to the completion of the goals.
The crew selection process must not only take into account the expertise and individual capacities needed but also the psychological factors that need to be considered when preparing for a long round trip where the human factor is perhaps the most important.
The size of the crew will impact the mission significantly, for the number of humans on board determines the mass of life support systems needed and this in turn places a constraint on the propulsive system chosen, as it will be the total mass of the spacecraft that drives the rocket design. During all previous manned missions designers have battled endlessly to squeeze masses to a minimum in order to be able to find propulsive systems with the necessary thrust to place the payloads in orbit.
What frequently happens is that the minimum size of the crew is decided on the basis of purely operational considerations, that is, selecting the crew that would optimally lead to the meeting of all mission goals within the safety margins required. If the design allows for more crewmembers mission planners will then be more than happy to find tasks for them and extend the mission goals.
In our manned missions, Mars Academy members held an initial web chat to exchange ideas on crew selection issues. A transcript of that chat may be read here.
Then, another chat was held, this time with Drs. Jack Stuster, NASA researcher and Claude Bachelard, medical director of the French Polar Institute, who clarified some of the issues related to crew integration factors and the psychology of long duration missions. A transcript of the chat is online.
Based on these two chats, the best compromise between the need to select astronauts that would be able to perform the various functions required of them and the propulsive design constraint was determined to be achieved by a crew of four.
Once the number of crewmembers is decided, the next step involves precisely defining each member’s function. Click here to decide on the crewmember functions.
At the same time, a selection process must be established. We are in the process of defining functions that the astronauts will have to perform during the mission. The selection process needs to ensure that the right individuals are chosen and through the selection criteria determine not only if they will be able to respond to the numerous challenges that they will face in this long duration mission but also that they will function accordingly as a human group.
In order to do this, we are developing several sets of questions and criteria that will help us assess the future astronaut’s suitability for the mission.
The general questions will have to do with the individual’s personal characteristics and his personal background. Criteria should thus be based on gender, nationality, marital status, age, etc
Technical questions are more specific to each position. They will depend on the nature of the position to be filled and the functions to perform. The criteria are thus based in this case on studies, technical background and professional experience.
Psychological questions will intend to evaluate the candidate’s adaptability and character and his ability to contribute to a reduced group that will live in isolation and confinement for almost three years.
The following online forms allow our members to submit questions and criteria for each of the above sections:
The Mars Astronaut Quiz is available to rate the future astronaut’s general knowledge on Mars and a manned mission to the Red planet. The online version of this quiz is now available and will give potential future virtual astronauts an idea of how well they are prepared for the mission.
Trajectory
There are many routes that take to Mars. Determining the adequate trajectory to the Red Planet involves the precise computation of all gravitational influences and the calculation of the velocities needed to transfer to Mars and come back to Earth.
From the different types of existing missions scenarios, we have chosen a minimum energy trajectory, called Hohmann transfer orbit, that minimizes propulsion requirements. This trajectory results in a round trip of approximately 2 ½ years.
Propulsion
Like in the old days, when engineers strove to conceive a rocket that would transport humans to the Moon, this time once again propulsion constitutes a sizable challenge. The great distances involved and the need to minimize transfer time are factors that will drive propulsion requirements to a maximum.
In our project, we have included a brief discussion on the alternative of launching direct from Earth or from a future Space Station in low Earth orbit, followed by an explanation of the concepts defined for measuring the propulsion efficiency of an engine and thus being able to compare available propulsion systems.
A description of the different types of rocket engines is followed by the description of the possibilities of two near term foreseeable propulsion systems that might be utilized on a trip to Mars: nuclear propulsion and ion engines.
Life Support Systems
A major design milestone, the life support system will ensure that astronauts make the trip in a friendly environment and stay in good health until their return to the Earth. The life support system for a manned mission to the red planet will be substantially different to previous manned missions that, basing themselves on the limited duration of the trip, were physico chemical.
For a 3 year mission, the life support system needs to perform a series of extended functions to ensure habitability and good health. The most important of these functions can be grouped in food production, waste recycling, air recycling and water recycling.
Space Medicine
For several obvious reasons, outer space is not a friendly destination at all. The life support system will provide a survivable atmosphere, but nonetheless other hidden dangers assail the space traveler.
Medical effects of spaceflight include bone marrow loss (at a max rate of 1.5% a mass, which is life threatening for a long duration mission) and several other that are less esrious and can be overcome with exercise or medication.
In order to avoid prolonged exposure to microgravity, the spacecraft will be spun around in order to generate artificial gravity.
This involves utilizing a dead mass that could for example be an expended rocket stage, to be tethered to the crew cab and adding the necessary propellant for the spin up and down cycles.
Mission Design
The mission design is a complex interdisciplinary task that involves coordinating various subsystems and the work of separate designers into a unique spacecraft solution. Two examples are provided of such designs in preparation for our own mission design. The Mars Direct mission is advocated by Dr. Robert Zubrin from Pioneer Astronautics and the Mars Reference Mission was produced from the NASA/Boeing 90 day study.
We can start outlining our own mission with approximate masses of the different stages in our Interactive Mission Design Page.
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Mars Intro | Landing
Site | Crew | Trajectory |
Propulsion | Life Support
Medicine | Mission
| Integration