ESA Document - Emits - ESA
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ESA Document - Emits - ESA

ESA Document - Emits - ESA ESA Document - Emits - ESA

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s The TV is composed of the THM and the propulsion stages, TMI, MOI, TEI THM lifetime shall be longer than 6 years 6 Years Life time of propulsion stages shall be long enough to cover the assembly in orbit and mission phases for which they are designed Each propulsion module shall be discarded in a safe way after its usage 2 5 Probability of Mars impact shall be lower than10^-4 THM shall be safely discarded, avoiding the Earth Moon system 10^-4 Science and exploration shall be performed on board during transfer and orbiting around Mars phases THM shall provide a storm shelter to protect the crew in case of a Solar Particle Event 600 kg THM shall be able to suport life during at least the mission duration and TBD during assembly in orbit THM shall provide communications with the Earth and the MEV THM shall provide EVA capabilities: * shall provide an airlock * shall provide EVA suits TMI shall provide the required impulse to put the TV on its orbit towards Mars MOI shall provide the required impulse to put the TV on its orbit around Mars TEI shall provide the required impulse to put the TV on its orbit towards Earth 6 3 THM shall provide the capability of manoeuvring to skip the Earth Mars system at Earth return Mission Constraints Assembly in LEO 400.00 km Assembly shall take no longer than 2 years 2.00 2.00 Years Safety Requirements Rescue of the crew and/or abort of mission shall be possible during phases: TBD TBD Single failure/fault/operator error tolerance for critical hazards. Two failure/fault/operator tolerance for catastrophic hazards. Failure detection, isolation and recovery means shall be provided (automatic and manual) TV shall provide automatic detection means for at least the following hazards: * Fire * Depressurisation * Biohazards * Atmosphere degradation conditions * Radiation * Temperature * Food spoilage and water contamination The TV shall provide a Caution and Warning System (C&W, this system must be able to receive system data, inform the crew of off-nominal events, and provide sufficient information to direct the crew to the correct response) TV shall be one failure tolerant to prevent loss of an EVA crewmember due to inadvertent separation from TV The TV shall have a 0.81 (minimum) combined probability of no penetration (PNP) of meteorite/orbital debris 0.81 critical items during the mission Physiology Requirements g-loads should be lower than (in the +Gx axis) * Earth Departure 6.00 g * Mars Arrival 4.00 g * Mars Departure 4.00 g * Earth Arrival 4.00 g Habitable volume per crew member shall be: THM shall provide appropiate public and private areas to sustaint optimal living and working conditions Radiation Organ Specific Equivalent dose Limits (BFO) 30.00 20.00 25.00 m^3 Accute event 0.15 0.15 Sv 30 days 0.25 0.25 Sv Year 0.50 0.50 Sv Career THM shall provide equipment in order to minimise the deconditioning of the crew, exercise and artificial gravity shall be considered THM shall provide medical equipment for the crew See Human Factors for more details 1 to 4 1 to 4 1.00 Sv HMM Assessment Study Report: CDF-20(A) February 2004 page 126 of 422

s Operational Requirements It shall be possible to command the TV in an automatic way TV shall be controllable from Earth TV shall be controllable by the crew Crew shall be able to override the automatic control EVA operations shall be kept to a minimum during transfer and orbiting around Mars phases Capability of inspecting the the external and internal parts of the vehicle shall be provided TV shall provide means for corrective and preventive maintenance Crew time dedicated to maintenance shall be minimised On-board training capabilities shall be provided Assembly in orbit Assembly in orbit shall be as automated as possible 0.00 Assembly shall be performed in LEO Capability for verification on orbit shall be provided * all connections shall be verified * all functions shall be verified Replace/Repair capability of system modules shall be provided during the assembly phase to ensure full functionality and redundancy prior to committing to departure 400.00 km Assembly phase shall kept as short as possible Planetary Protection Requirements For the forward contamination: 1.) The probability of an impact on Mars by any part of the launch vehicle (also launch from LEO in that case) shall not exceed 1E-4 2.) If the Mars orbiting spacecraft does not meet the Viking pre-sterilization bioburden levels the probability of an impact on Mars shall not exceed 1E-2 for the first 20 years of the mission, and shall not eceed 5E-2 for the time between 20 and 50 For backward contamination: 1.) All sample material returned from Mars shall be contained, and containment shall be verified before entering the Earth- Moon system 2.) It shall be possible to isolate the surface crew from the rest of the crew on the habitation module for a TBD period of time after returning from the surface of Mars. 3.) Contamination of the THM shall be avoided during all mission phases (in that respect, docking the ascent vehicle and transfer of crew and material from there to the habitation module is critical) Interface requirements 2.00 2.00 Year Interfaces between assembly elements shall be kept to a minimum to simplify the assembly THM shall be as independent as possible from the Propulsion Transfer Stages THM shall provide interfaces with the ERC, allowing the crew to pass from THM to ERC and back THM shall provide interfaces with the MEV, allowing the crew to pass from THM to MEV and back THM shall provide interface with the Propulsion Transfer Stages to transmit the loads and commands THM shall act as data relay between the MEV and Earth THM shall provide housekeeping functions to the rest of the mission elements (ERC, MEV) when they are in stand by Interfaces shall be standarised Propulsion All propulsion stages shall be designed to provided the required trajectory changes at each mission phase Staging shall be considered within each main propulsive manoeuvre (TMI, MOI, TEI) Cryogenic stages shall be considered for TMI Table 3-1: Transfer Vehicle high level requirements HMM Assessment Study Report: CDF-20(A) February 2004 page 127 of 422 After the realisation of the study, it was discovered that some of these requirements cannot be fulfilled with the proposed design. For example: • Mission success requirement cannot be evaluated at this stage • Assembly in orbit cannot be performed in less than 2 years even in the most optimistic scenario • Lifetime of the different modules will have to be set after the assembly in-orbit sequence is defined • Abort is not possible during all the mission phases 3.1.2 System design drivers The THM main design drivers are: • The habitability requirements, which determine the size of the vehicle. A minimum of 25 m 3 has to be provided for each astronaut. It leads to a total pressurised volume of 450 m 3 • It is the main payload for the propulsion module, so its mass has to be as low as possible • High level of closure of the life support system to reduce the total mass • Launcher constraints in terms of dimensions

s<br />

The TV is composed of the THM and the propulsion stages, TMI, MOI, TEI<br />

THM lifetime shall be longer than 6 years 6 Years<br />

Life time of propulsion stages shall be long enough to cover the assembly in orbit and mission phases for<br />

which they are designed<br />

Each propulsion module shall be discarded in a safe way after its usage<br />

2 5<br />

Probability of Mars impact shall be lower than10^-4<br />

THM shall be safely discarded, avoiding the Earth Moon system<br />

10^-4<br />

Science and exploration shall be performed on board during transfer and orbiting around Mars phases<br />

THM shall provide a storm shelter to protect the crew in case of a Solar Particle Event<br />

600 kg<br />

THM shall be able to suport life during at least the mission duration and TBD during assembly in orbit<br />

THM shall provide communications with the Earth and the MEV<br />

THM shall provide EVA capabilities:<br />

* shall provide an airlock<br />

* shall provide EVA suits<br />

TMI shall provide the required impulse to put the TV on its orbit towards Mars<br />

MOI shall provide the required impulse to put the TV on its orbit around Mars<br />

TEI shall provide the required impulse to put the TV on its orbit towards Earth<br />

6 3<br />

THM shall provide the capability of manoeuvring to skip the Earth Mars system at Earth return<br />

Mission Constraints<br />

Assembly in LEO 400.00 km<br />

Assembly shall take no longer than 2 years 2.00 2.00 Years<br />

Safety Requirements<br />

Rescue of the crew and/or abort of mission shall be possible during phases: TBD TBD<br />

Single failure/fault/operator error tolerance for critical hazards.<br />

Two failure/fault/operator tolerance for catastrophic hazards.<br />

Failure detection, isolation and recovery means shall be provided (automatic and manual)<br />

TV shall provide automatic detection means for at least the following hazards:<br />

* Fire<br />

* Depressurisation<br />

* Biohazards<br />

* Atmosphere degradation conditions<br />

* Radiation<br />

* Temperature<br />

* Food spoilage and water contamination<br />

The TV shall provide a Caution and Warning System (C&W, this system must be able to receive system data,<br />

inform the crew of off-nominal events, and provide sufficient information to direct the crew to the correct<br />

response)<br />

TV shall be one failure tolerant to prevent loss of an EVA crewmember due to inadvertent separation from TV<br />

The TV shall have a 0.81 (minimum) combined probability of no penetration (PNP) of meteorite/orbital debris<br />

0.81<br />

critical items during the mission<br />

Physiology Requirements<br />

g-loads should be lower than (in the +Gx axis)<br />

* Earth Departure 6.00 g<br />

* Mars Arrival 4.00 g<br />

* Mars Departure 4.00 g<br />

* Earth Arrival 4.00 g<br />

Habitable volume per crew member shall be:<br />

THM shall provide appropiate public and private areas to sustaint optimal living and working conditions<br />

Radiation Organ Specific Equivalent dose Limits (BFO)<br />

30.00 20.00 25.00 m^3<br />

Accute event 0.15 0.15 Sv<br />

30 days 0.25 0.25 Sv<br />

Year 0.50 0.50 Sv<br />

Career<br />

THM shall provide equipment in order to minimise the deconditioning of the crew, exercise and artificial gravity shall be<br />

considered<br />

THM shall provide medical equipment for the crew<br />

See Human Factors for more details<br />

1 to 4 1 to 4 1.00 Sv<br />

HMM<br />

Assessment Study<br />

Report: CDF-20(A)<br />

February 2004<br />

page 126 of 422

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