Minimalist Mars Mission

Establishing a Human Toehold on the Red Planet

Executive Summary

DevelopSpace MinMars Team

MinMars: Motivation and Concept

• Ultimate goal: sustainable human expansion into space – making humanity a multi-planetary species

• Logical first step towards this goal: establishing a human settlement on Mars and expanding it into a mostly self-sustaining colony

– Why Mars? Mars is the best choice for an initial settlement (resources, atmosphere, gravity, accessibility / transportation requirements)

• MinMars is concerned with establishing an initial human toehold: 4 humans get to Mars and remain there for the rest of their lives

– Functionally corresponds to Bob Zubrin’s exploration and base phases

– The initial crew proves long-term habitability and tests the technologies necessary to establish a more expansive human settlement and colony

• The DevelopSpace MinMars study is intended to establish toehold near-term feasibility and identify important topics for detailed work

– Somewhat similar in function to NASA’s Mars design reference missions

MinMars Toehold Outpost Architecture• Habitat: assembled out of several modules (hard-

shell as well as inflatable); number of modules dependent on Mars lander payload (2 mt assumed)

• Power: thin-film solar arrays & li-ion batteries

• Location: around 30 deg northern latitude due to solar power generation concerns

• Life support & ISRU: high-closure life support with water distillation and filtering; in-situ oxygen and buffer gas production; initially no in-situ water production, water required for loop closure is imported

• Resupply: very conservative estimate of ~24 mt of resupply per opportunity (for 4 crew); would require 12 launches with performance 30 mt to LEO (old SpaceX Falcon 9 Heavy performance class)

• Surface mobility: unpressurized rovers (exploration radius of 20-50 km); would be similar to NASA’s lunar mobility chassis

Image credit: NASA

Cargo Transportation

Earth

Mars

Low Mars Orbit

Highly Elliptic Earth Orbit (e.g. GTO)1-13 monthsof loitering

Direct Mars entry (lifting) using anextension of Viking EDL technology

Commercial Earth launch(e.g. on a Falcon 9 Heavy)

Trans-Mars coast (~ 6-8 months)

2 mt of useful payload on the surfaceof Mars; 1 km landing accuracy

Pre-deployed beacon

Note: concept based on oldSpaceX Falcon 9 Heavyperformance numbers –

needs to be revised

Mars EDL Concept• Analyses indicate that existing Mars EDL technology can be

extended to a payload mass of 2000 kg– See NASA Mars Design Reference Architecture 5.0

– Existing Mars EDL technology was developed for Viking

• => Extension of the MSL EDL system (however, no skycrane, lander stage instead):

– MSL ballistic coefficient: 115 kg/m2

– MSL reference area (4.6 m diameter): 16.62 m2

– Payload mass fraction on entry: 775 kg / 2800 kg = 0.28

– MSL hypersonic drag coefficient: 2800 kg / (115 kg/m2 x 16.62 m2) = 1.46

– MSL propellant mass estimate: 8 x 50 kg = 400 kg

• MinMars EDL system characteristics:– Entry mass: 2000 kg / 0.28 = 7143 kg

– Reference area: 7143 kg / (1.46 x 115 kg / m2) = 42.54 m2

– Aeroshell diameter: 7.36 m

– Lander propellant mass: 2000 kg / 775 kg x 400 kg = 1032 kg

– EDL system dry mass (including the cruise stage):8000 kg – 2000 kg – 1032 kg = 4968 kg

Ballisticcoefficient:

MSL scaled up

7.36 m

MinMars aeroshell

Payload envelope(cylinder):1.5 m diameter,2.5 m height

Note: concept based on oldSpaceX Falcon 9 Heavyperformance numbers –

needs to be revised

Crew Transportation (for 2 Crew)

Earth

Mars

Low Mars Orbit

Low Earth Orbit (e.g. GTO)

1-5 months of loitering forEarth departure stages

Direct Mars entry (lifting) using anextension of Viking EDL technology

Commercial cargo launch(e.g. on a Falcon 9 Heavy)

Trans-Mars coast (~ 6 months)

2 crew members on the surfaceof Mars; 1 km landing accuracy

Pre-deployed beacon

Mars lander

ITH Earthdeparturestage 2

Earthdeparturestage 1

Commercial crew launch(e.g. Falcon 9 / Dragon)

Earth departure stages discarded

ITH discarded

Note: concept based on oldSpaceX Falcon 9 Heavyperformance numbers –

needs to be revised

Net-Present-Cost (NPC) Analysis Assumptions

• Cost estimates for spacecraft, surface infrastructure, and propulsion systems carried out with mass-based CERs– All estimates in FY04 $ Mn

• Launch cost for a Falcon 9 Heavy class launch vehicle assumed to be FY04 $ 150 Mn

• Learning rates (and associated reduction of unit costs) not included in the analysis presented here

• Non-discounted as well as discounted analyses (sensitivity analysis to discount rate)

• Time horizon for DDT&E: 5 opportunities (~ 10 years)

Please note: this is a notional analysis intended only to assessorders of magnitude and relative importance of cost contributions

NPC by Category

Non-discounted 5% discount rate 10% discount rate

Note: concept based on oldSpaceX Falcon 9 Heavyperformance numbers –

needs to be revised

Technology Investment Options• In-situ food production

– Could significantly improve resupply cost and risk (dependence on Earth-based supply)

• In-situ water production– Could significantly improve resupply cost and risk (dependence

on Earth-based supply)

• In-situ production of spare parts– Could significantly improve resupply cost and risk (dependence

on Earth-based supply)

• Higher-payload-mass EDL systems + HLLV– Reduces the number of landings, assembly operations– Makes most sense when combined with a higher-payload Earth

launch capability (50 – 70 – 100 mt to LEO)

• Advanced EVA suits for Mars surface environment– Could significantly improve resupply cost (no metal oxide)