Mars Direct

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The Mars Direct mission sequence.

Mars Direct is a proposed mission architecture, developed by Robert Zubrin and David Baker at Martin Marieta in 1990. Mars Direct uses a reduced set of technologies to land a small crew on Mars for a long duration science mission. This plan was summarized in the book, The Case For Mars, written by Robert Zubrin and Richard Wagner. Mars Direct was innovative for its use of in situ resource utilization (ISRU) and for its use of direct launch from Earth to Mars without orbital construction or Mars orbit rendezvous. Mars Direct relies on separate outbound and return vehicles, and a pipelined mission architecture for improved redundancy. It has inspired several later proposed mission plans, including NASA's Design Reference Mission.


There has only ever been one one Mars Direct proposed mission architecture. However, in some circles "Mars Direct" has become shorthand for any mars mission profile which reduces payloads and costs with ISRU and direct launch trajectories, including variants that make use of nuclear thermal rockets and NASA's Design Reference Mission. The term "Mars Semi-Direct" was coined by Robert Zubrin to describe otherwise similar mission architectures that employ of Mars orbit rendezvous.

This wiki article is about the original proposed mission architecture, and includes secondary discussion of only those variants described by the original authors, Robert Zubrin and David Baker.


In The Case for Mars, Robert Zubrin estimated the cost of development and operation of 3 missions at $20 - $30 billion.

Mass Figures

To see a much-expanded article focusing specifically on this information, see the article Mass Allocations for Mars Direct

On page 93 of The Case For Mars Zubrin gives the following numbers for the masses of each component. These are the masses to Mars's surface and not to orbit. Basically all of the mass is assigned either to the Hab or to the ERV. This topic is elaborated on more

Hab (Habitation Module)

Habitation Module
Component Mass
Hab structure 5.0 mt
Life-support system 3.0 mt
Consumables 7.0 mt
Electric power (5 kWe solar) 1.0 mt
Reaction control system 0.5 mt
Comm. and Info. Mgmt. 0.2 mt
Lab equipment 0.5 mt
Crew (4) 0.4 mt
EVA Suits (4) 0.4 mt
Furniture and interior 1.0 mt
Open rovers (2) 0.8 mt
Pressurized rover 1.4 mt
Field science equipment 0.5 mt
Spares and margin (16%) 3.5 mt
Total Mass 25.2 mt

ERV (Earth Return Vehicle)

Earth Return Vehicle
Component Mass
ERV cabin structure 3.0 mt
Life support system 1.0 mt
Consumables 3.4 mt
Electrical power (5 kWe solar) 1.0 mt
Reaction control systems 0.5 mt
Comm. and Info. Mgmt. 0.1 mt
Furniture and interior 0.5 mt
EVA suits (4) 0.4 mt
Spares and margin (16%) 1.6 mt
ERV cabin total 11.5 mt
Aeroshell 1.8 mt
Light truck 0.5 mt
Hydrogen feedstock 6.3 mt
ERV propulsion stages 4.5 mt
Propellant production plant 0.5 mt
Power reactor (80 kWe) 3.5 mt
Total Mass 28.6 mt


Consumable Requirements for Mars Direct Mission with Crew of Four
Item Oxygen Dry-food Whole-food Potable-water Wash-water Total
Need/man-day 1.0 0.5 1.0 4.0 26.0 32.5
Fraction recycled (kg) 0.8 0.0 0.0 0.8 0.9 0.87
Wasted/man-day 0.2 0.5 1.0 0.0 2.6 4.3
ERV Reqs 200 days in (kg) 160 400 800 0 2080 3440
Hab Reqs 200 days out (kg) 160 400 800 0 2080 3440
Hab Reqs 600 days surface (kg) 0 1200 2400 0 0 3600
Hab Reqs Total (kg) 160 1600 3200 0 2080 7400

See Also

New Mars Forum Discussions

A Bigelow Mars Direct?

The Biggest Real Problem with Mars Direct

Euro Version of Mars Direct

Has Dr Zubrin Addressed Mars Direct Objections?

Long Duration Lunar Mission Dry Run for Mars Direct

My Change To Mars Direct/Semi-Direct Mission Plans

Documentary on Mars Direct Trailer - Based on Zubrin's Case for Mars

Space Elevator vs. Mars Direct - Anyone Compare the Costs?

Where Exactly is Mars Direct with NASA?

Reasons Against Mars Direct

Mars Direct Still on the Table?

How to Kill Mars Direct

Mars Direct - How Much Does It Cost?

How to Sell MArs Direct

An All Solar Mars Direct

Mars Direct Rethought - Fixing the Potholes in Zubrin's Plan

Mars Direct International

Merits of Mars Direct - Is It Too Optimistic?

Mission Risk Involving Mars Direct

Revive the Saturn V for Mars Direct

External links