Project Columbus Equipment and Schedule

Project Columbus is named for the explorer of the Americas and is conceived as an international effort to land people on Mars in order to set up an outpost from which the Red Planet can be explored and studied. The plan assumes (1) the use of expendable commercial rockets capable of launching about 24 tonnes to low earth orbit such as the Ariane 5, Delta IV Large, and the Angara (this is the capacity of the Space Shuttle as well); (2) solar powered ion-propulsion vehicles capable of lifting cargo to (3) Gateway, an occasionally staffed space station located at the Lagrange Point (L1) between the Earth and the Moon; (4) chemical propulsion from Gateway to the lunar surface and Mars; and (5) use of hydrogen and oxygen propellant derived from the permanently shaded regolith at the lunar south pole. It assumes that the moon will be visited first, Mars second. Its ideas from various authors, but especially from Michael Duke’s “A Lunar Reference Strategy,” which can be seen at http://members.aol.com/dsportree/MM22.htm, and from Robert Zubrin’s “Mars Direct” proposal. It also utilizes technology from (Patrick J. G. Steinnon and David M. Hoerr, The Rocket Company, http://www.hobbyspace.com/ AAdmin/archive/SpecialTopics/RocketCom/chap01.html) and from a recent proposal from NASA’s NeXT Task Force proposing a station at L1 called Gateway (http://www.space.com/news/beyond_iss_020926-1.html). It assumes technology available near term (i.e., extrapolations of existing technology). One feature is the reusability of the principal transportation elements. Another is use of solar power instead of nuclear power.

EQUIPMENT

1. SOLAR-ION PROPULSION TUG

High-efficiency solar panels and mirrors (250 kw), ion engine (Isp, 3,300 seconds), avionics, communications, power converters, structure, etc.

6 tonnes

Propellant and tanks 6 tonnes (typical)

NASA TM-2002-211970 (Timothy Sarver-Verhey et al), describe an 11.3 tonne solar-electric vehicle using nine 50-kw gridded ion thrusters and 12.2 tonnes of xenon to move 36.6 tonnes of payload to Earth-Moon L1 in 270 days. The vehicle would have thin-film solar arrays totalling 2,685 square meters (mass 0.33 kg/m2 or 900 kg). Arrays and engines would have a 2-year design lifetime. The design includes a 2.2 tonne margin for the ion engine mass (it could be as much as 13.5 tonnes, or if it is 11.3 tonnes the payload is 38.8 tonnes).

This tug is half as large and moves 18 tonnes of payload. They are named for lunar rilles (Schroeder, Hadley, etc.).

Note that Michael Duke’s Solar-Electric Propulsion Vehicle was projected to mass 4 tonnes, use 4-5 tonnes xenon, and push 16 tonnes to L1. This was a bit optimistic.

Note: xenon costs $17 million per tonne and the Earth’s total production is 50 tonnes per year.

2. AUTOMATED CARGO VEHICLE (ACV), mass 19 tonnes (launched from Earth with 6 tonnes of ion engine propellant to push it to Gateway)

Fuel Tanks (cap., 4.0 tonnes LOX/methane) 0.3 tonnes

Engines (2, 20 tonnes thrust each) 0.8 tonnes

Parachute 1.0 tonnes

Heat shield/ACV base 3.0 tonnes

Legs 0.2 tonnes

Avionics 0.1 tonnes

Reaction Control 0.3 tonnes

Landing methane 0.8 tonnes (delta-vee, 800 m/sec)

[Landing oxygen from moon 2.8 tonnes]

Cargo (Martian surface): 12.5 tonnes

Cargo (Mars orbit): 15.5 tonnes

Cargo (Phobos/Deimos): 14.0 tonnes

Trans-Mars injection (TMI) is supplied by a Lifter. Methane for landing comes from the Earth; liquid oxygen from the moon or Phobos and is supplied to the ACL at Gateway. ACLs follow a Hohmann trajectory to Mars.

Delta-vee, Lagrange 1 to Hohmann transfer orbit, plus course corrections: 0.8 km/sec (mass ratio, 0.25:1 for methane)

Delta-vee, Mars landing: 0.8 km/sec (mass ratio, 0.25:1 for methane)

Note: NASA is currently developing a standard “platform” for landing scientific packages of up to about 1 tonne on Mars called the “smart lander.” The ACL could be a twelve-fold expansion of that vehicle.

Once an Outpost is well established on Mars the lander version is phased out, because the Mars Shuttle can deorbit cargo.

3. INTERPLANETARY TRANSIT VEHICLE (ITV), mass 16 tonnes

Cabin structure 4.0 (1 tonne more than ERV cabin)

Life support system 2.0 (1 tonne more than ERV cabin)

Consumables 3.4* (for six months only)

Electrical Power (10 kw) 1.0* (assumes more powerful solar arrays)

Reaction control system 0.5*

Computers 0.1*

Furniture and Interior 0.5*

EVA suits 0.4*

Spares and Margin 2.3 (0.1 tonnes more than the Mars Direct

ERV, to make the total 16 tonnes)

Aeroshell 2.4 (0.6 tonnes heavier than Mars Direct)

(* = numbers from ERV in Robert Zubrin, The Case for Mars, p. 92)

The ITV is about half way between the Mars Direct’s Hab and its ERV cabin in mass and volume. It is a cone with a 6-meter basal diameter and a height of 13 meters. It has five floors with 28, 23, 16, 9, and 3 square meters respectively (total, 79 square meters). Its interior volume is about 183 cubic meters. The base is covered by a heat shield ten meters in diameter. Its long, thin shape is ideal for rotation to produce artificial gravity when docked to a counterweight (if docked to another ITV via a two-meter docking cube, 5 rpm will produce Mars normal gravity [0.385] on the bottom floor)(4 rpm gives 0.25 gravities, 7 rpm 0.75 gravities and 8 rpm 0.98 gravities for the return trip to Earth).

The ITV can be launched into low earth orbit with 2 tonnes of extra consumables (for the surface) and 6 tonnes xenon propellant that pushes it to Lagrange 1 over six months. A Lunar-Based “Lifter” or a Mars shuttle pushes it to Mars. The shuttle and ITV remain docked and serve as a counterweight to each other for the generation of artificial gravity. The IHab aerobrakes into a high Mars elliptical orbit and remains there untended 18 months. The crew returns from Mars and heads back to Earth using fuel manufactured on the Martian surface. The ITV aerobrakes into Earth orbit, is refurbished and resupplied (it needs perhaps 5 tonnes of new stuff for each flight), and is flown back to Mars two years later.

Delta vee from Gateway to fast trajectory to Mars: 1.2 km/sec (mass ratio 0.33:1 for LOX/LH2, 0.4:1 for LOX/ methane)

Delta vee from high Mars orbit to fast trajectory back to Earth: 1.5 km/sec (mass ratio 0.5:1 for LOX/methane)

Some ITVs are accompanied by a Docking Cube, an inflatable cubical structure two meters in diameter with a docking port on each of its six faces. Its total mass is one tonne and it allows up to six vehicles to dock together. The cube allows large complexes to be flown to Mars including up to four ITVs and two shuttles.

Note: Various stripped down versions of the ITV are possible since the structure is only 4 tonnes, life support 3 tonnes, and other essential features 1 tonne. Thus two stripped down ITVs could be flown to Mars to provide additional housing on the flight out and could be left on the moons to provide emergency shelter. Later they could be refurbished and flown back to Earth if needed. A version of the ITV could be used as a passenger vehicle between the Earth and moon.

4. MARS SHUTTLE (MS), a reusable piloted or automated passenger or cargo spacecraft

Crew Module 4.0

Structure 10.0 (plus 2 tonnes parachutes)

Aerobrake variable (typically 6 tonnes)

The Mars shuttle has a 6-meter basal diameter and is 16 meters high (three meters longer than the ITV). Its aerobrake is sized to place 40 tonnes into high Mars orbit from interplanetary space (15-tonne vehicle including crew module, 12 tonnes cargo, 13 tonnes landing fuel without parachute; 15-tonne vehicle, 2 tonnes parachutes, 15 tonnes of cargo, 8 tonnes of landing fuel with parachute).

The Mars Direct ERV’s structure weighs 4.5 tonnes (Case for Mars, p. 92) and contains about 110 cubic meters of fuel storage volume. The ERV mass includes a heat shield and parachute for landing the crew cabin on Earth, but not for landing the entire vehicle on Mars. It includes engines for two stages, a cargo hold (probably about 10 cubic meters), and extra tanks for water (10 cubic meters). Thus the vehicle has a mass of 4.5 tonnes/140 cubic meters = 0.0321 tonnes per cubic meter.

A proposal for a two-stage reusable shuttle to low Earth orbit (Patrick J. G. Steinnon and David M. Hoerr, The Rocket Company, http://www.hobbyspace.com/ AAdmin/archive/SpecialTopics/RocketCom/chap07page2.html) has a structural mass for the second stage of 5.9 tonnes, including heat shield, parachute (7% of the total, with a redundant duplicate also massing 7%), landing wheels (1.5% of total), and more powerful engines than the Mars Shuttle needs. It uses 39 tonnes of liquid hydrogen and oxygen, which require a volume of 103 cubic meters, and has a cargo hold with a volume of 31 cubic meters. The two vehicles thus appear to be almost identical in size. They also appear to be about the same diameter and length. If one subtracts the parachute mass and the gear for a runway landing from the terrestrial shuttle, the remainder is 5.0 tonnes, in excellent agreement with Mars Direct’s vehicle (this totals 5 tonnes /134 cubic meters = 0.373 tonnes per cubic meter). It is assumed no additional heat shield is needed for Mars landing, but that additional mass is needed for aerobraking into orbit around the Earth or Mars because of the higher velocities involved.

The Mars shuttle’s fuel occupies 181 cubic meters. The vehicle also includes a 70 cubic meter cargo compartment (6 meters in diameter; 2.5 meters high; 28 square meters of floor space) in its base, above the engines and below the fuel tanks. The door folds down to provide a ramp to the ground. The top of the vehicle features a docking mechanism and a “capsule” 2 meters high and 1.5 meters in diameter (4 cubic meters) with a docking mechanism on top (which can be used as emergency astronaut accommodation); an inflatable tunnel can be attached to the outside of the vehicle to give access to the cargo hold from the capsule during interplanetary cruise. The total of 255 cubic meters at 0.0373 tonnes per cubic meter gives a mass of 9.5 tonnes (here rounded to 10 tonnes, to provide margin). If parachutes are employed in landing, one must increase this by about 2 tonnes.

The crew module is placed in the cargo compartment if the vehicle is to be flown with crew. For details, see crew module below. The crew module includes space for cargo.

Landing delta-vee with parachute system: 0.7 km/sec (mass ratio 0.25:1 methane)

Cargo capacity (down): 16 tonnes

Landing delta vee without parachute: 1.5 km/sec (mass ratio 0:5:1 for methane)

Cargo capacity (down): 15 tonnes

Delta-vee to ITV: 5.4 km/sec (mass ratio 3.5:1 for methane)

Cargo capacity up: 20 tonnes (fuel needed by Mars shuttle and ITV for trans-Earth injection)

Fuel consumption, up: 130 tonnes

Cargo capacity up (using 150 tonnes of fuel): 25 tonnes (with crew compartment); 30 tonnes (no crew)

Delta-vee to low Mars orbit: 4.2 km/sec (mass ratio 2.1:1 for methane)

Note: delta-vee to Phobos and to the ITV are about the same, which means a fully fueled Mars shuttle could fly to Phobos with 3 tonnes of cargo, conduct exploration or maintain equipment, then return to the surface with 2 tonnes of cargo.

Note: The Mars Shuttle always lands with a parachute the first time. If the parachute cannot be repacked and reused (which is probably the case), subsequent flights require landing delta-vee of 1.5 km/sec. Subsequent flights are dependent on use of Martian water to make fuel.

To make 155 tonnes of LOX/methane on Mars (130 for the flight to the ITV and 20 to push the shuttle and ITV back to Earth) requires 7.75 tonnes of liquid hydrogen and about 50 kilowatts of power over two years (about 75 kilowatts over 18 months).

Once large quantities of water become available on the Martian surface (30 tonnes per year or more) the 10 tonnes of feedstock hydrogen flown up from Earth is replaced by cargo.

The Mars Shuttle carries the crew from the ITV in high Mars orbit to the surface and returns them to the ITV eighteen months later. The Shuttle brings up the 20 tonnes of fuel necessary to push both back to Earth. The Mars Shuttle remains at Mars through two oppositions, then returns to Earth to be refurbished. It is capable of up to five or six round trips.

The novel Mars Frontier assumes that two shuttles and two ITVs are flown to Mars each time and one is left as backup at each planet. This increases the crew flown (which makes the plot more interesting) and makes the mission safer.

5. MARS SHUTTLE CREW MODULE (CM), mass 4 tonnes

The crew module is an inflatable structure that fits in the Mars shuttle’s cargo compartment (28 square meters; ¼ the size of the Mars Direct’s hab, half the size of the ERV cabin). It has one side where all its equipment (electronics, stove, toilet, airlock) is located. The rest of the structure can be deflated and pressed against that side, so that it can be removed from the cargo compartment (furniture and possessions must be removed first). Some cargo can be stuffed into the deployed CM as well.

The CM is normally meant for 2-4 weeks of use, but in an emergency, with the proper supplies, can be used for six months.

6. LIFTER, A-CLASS.

Dry mass 2.1 tonnes (excluding aeroshield)

Maximum LH2/LOX capacity 16 tonnes

Maximum methane/LOX capacity 36 tonnes

Lifters are any automated vehicle that lifts mass from an airless world to orbit or returns mass to that airless world (such as the moon, Phobos, and Deimos). Their propellant area is 4 meters in diameter and 4 meters long. The cargo hold is below the tanks and above the engines, is 3 meters high and 6 meters in diameter, and includes a ramp for easy offloading. They can fly from the lunar surface to Gateway, pick up a maximum of 12 tonnes of cargo, and bring it to back to the moon. All are designed to use methane and oxygen propellant as well as hydrogen and oxygen. The later Lifter-B model (dry mass 4.3 tonnes) has a fuel capacity of 34 tonnes (methane/LOX, 76 tonnes). Lifters are designed for ten round trips from the lunar surface before they must be replaced. They are named for lunar maria (Serenitatis, Tranquillitatis, etc.).

NOTE: The Centaur upper stage has a total mass of 22.8 tonnes and a dry mass of 2.0 tonnes (8.8% of total); the Delta IV Large second stage has a total mass of 30.7 tonnes and a dry mass of 3.5 tonnes (11.4% of total). The Lifter-A dry mass is 10% of the total plus 0.3 tonnes for cargo accommodation and landing gear. The Lifter-B is 212% larger.

Delta-vee, lunar surface to Lagrange 1 Gateway (or back): 2.3 km/sec (mass ratio 0.64:1)

Launch capacity to Mars (10 tonnes LH2/LOX, Hohmann): 50 tonnes including itself; 46 tonnes with return of the Lifter to Gateway.

Launch capacity between Gateway and lunar surface (16 tonnes fuel): 12 tonnes

Launch capacity from low Earth orbit to Lagrange with 12.9 tonnes of LOX/LH2: 9 tonnes (plus 2.1 tonne vehicle)

Launch capacity: 24.6 hr elliptical to earth via Hohmann with aerobraking: delta-v, 1.2 km/sec (mass ratio 0.4:1), so: Lifter-B takes off from Phobos with 35.4 tonnes methane and 13.6 tonnes LOX (49.0 tonnes total, plus 5 tonnes vehicle and 5 tonnes aerobrake), tops off tanks at the 24.6 hr orbit, then heads for Earth, arriving (after aerobraking) with 31 tonnes of methane. This requires 108.5 tonnes of oxygen, making 139.5 tonnes propellant at Gateway. Vehicle arrives with 0.4 tonnes spare oxygen as well.

Standard cargo transfer procedure

Shuttle launches into Phobos transfer orbit with 24 tonnes of cargo

Meets ACV with 24 tonnes cargo from Earth. Cargos are swapped and shuttle returns to the surface of Mars.

ACV is propelled to the Earth by a Lifter-B with 32 tonnes propellant and 23 tonnes of methane cargo

Lifters are designed to be good for ten round trips between the lunar surface and Gateway (delta-vee, 4.6 km/sec per round trip). They remain at Mars three oppositions, then return to Earth for refurbishing.

7. INFLATABLE SURFACE HABITATS, diameter 12 meters, height 7 meters. The habitat is shaped like a flying saucer; the central section is a cylinder 12 meters in diameter and 2.2 meters high with hemispherical top and bottom caps up to 2.4 meters high each. Floor area of the main level: 113 square meters. The basement and attic levels have about 55 square meters each with headroom. Their crawl spaces (another 58 square meters each) are excellent storage areas.

Structure 8 tonnes

Life support 3 tonnes

Equipment, furniture 1.5 tonne

TOTAL 12.5 tonnes

The Mars Direct’s hab has a mass of 9.5 tonnes (structure, 5.0 tonnes; life support, 3.0; lab equipment, 0.5; furniture and interior, 1.0) and a floor area of 100 square meters. The Mars Direct’s ERV cabin has a mass of 4.5 tonnes (for the same items) and probably has a floor area of about 50 square meters, but has life support equipment for only six months. The Habitat is about twice the size of the Mars Direct Hab, but it is inflatable and does not have micrometeoroid protection, so its mass is 160% more. Its life support equipment can accommodate four persons; if more are housed, more mass is needed.

The Habitat houses 6, 8 in an emergency. If the upper and lower levels are used, it can house 10-12.

Note: Michael Duke assumes an 8-tonne habitat for his lunar transportation system.

8. GREENHOUSE, mass 4 tonnes

A greenhouse is an inflatable transparent structure of tough, transparent plastic (Kevlar, Nomex, Tefzel, etc.), six meters wide and 22 meters long, 132 square meters in surface area. They can be docked to inflatable structures (habs, for example) at either end. The structure itself masses 2 tonnes; the other 2 tonnes consist of air circulation and purification equipment, insulation/reflection blanket, motors to raise and lower the blanket, hoses, agricultural testing equipment, and a small quantity of fertilizer. The floor of the greenhouse is covered with recovered parachute material; walls of rocks are used to make raised beds for agriculture. The beds are filled with treated Martian soil in order to raise crops. It has airlocks at each end. At night a thermal blanket covers the inside of the arched transparent surface to hold in heat. At dawn the thermal blanket on the eastern side is lower to admit sunlight; the thermal blanket on the western side has a silvered inner surface to reflect horizontal solar rays downward onto the crops. During midday the thermal blankets are removed from both sides. In late afternoon the thermal blanket on the eastern side is raised and its silvered inner surface reflects the western rays downward onto the crops. By capturing solar energy that the plants would have otherwise missed, total solar insolation is raised to levels similar to those found on the Earth’s surface.

Each greenhouse should be able to treat the wastes and feed 1.5 to 2 people.

9. SOLAR POWER ROLL (SPR), mass 0.5 tonnes

Geoffrey A. Landis and Joseph Appelbaum in their paper “Photovoltaic Power Options for Mars” (http://powerweb.grc.nasa.gov/pvsee/publications/mars/marspower.html) state that a flat, unsteered solar array system on the surface of Mars massing 0.9 kg/m2 with a 20% conversion efficiency, receiving an average insolation of 3 kw-hrs per sol per square meter (note, however, this varies from a high of 4.2 to a low of 0.4 during global dust storms) could produce an average of 0.6 kw-hr/sol. Power conditioning, management, and distribution equipment would be of equal mass, doubling the number to 1.8 kg/square meter. Thus 1 kilowatt-hour per sol requires about 3 kilograms of mass total. They suggest that a rollout array could be manufactured. They also note that the Mars Direct ERV requires 107 tonnes of propellant, which requires 370 megawatt-hours of power (or 3.5 megawatt-hours per tonne).

In Mars-24, each ACV and Mars Shuttle is accompanied by one or more rolled up solar power arrays 3 meters wide and a total of 85 meters long, about a meter in diameter when rolled up (around a ½ meter plastic cylinder), having a mass of 250 kilograms with a 250 kg PCMD, capable of generating an average of 150 kilowatt-hours per day. Each roll comes in a plastic box and is attached to the shuttle on an extendable fifty meter cable. The vehicle lands in a spot free of large rocks so that the SPR can be unrolled over unprepared ground, or a remotely controlled vehicle bulldozes a path for it in a stony area. A door is opened and the outer blanket of the SPR is inflated, pushing it out of the box and cushioning it when it falls onto the ground. Then a pump inflates longitudinal hoses in the SPR with Martian air, causing them to stiffen and unroll it. Finally, latitudinal hoses are inflated, opening the array to its full width. Every lander comes with a 1,000 meter, 200-kilogram power cable that a remotely controlled vehicle can pull to the nearest lander, thereby plugging them together. The vehicle can also blow dust off the SPR periodically to keep it clean.

Note: if 32% efficiency solar cells are postulated, the roll’s output would be 240 kilowatt-hours per sol.

10. SOLAR POWER UNIT, mass 0.5 tonnes

The solar power unit is a transparent plastic cylinder 32 meters long and 30 meters in diameter. Half of the diameter of the cylinder is silvered; the cylinder rolls on the ground to keep the silvered side facing the sun so that the reflected sunlight falls on high-efficiency (32%) solar arrays on the opposite side of the cylinder. The arrays are 3 meters wide and receive 10 times the usual Martian level of insolation on them, which heats them to as much as 100 centigrade. The solar panels have a network of tubes running across their backs through which compressed Martian air is blown to extract the heat. The SPU’s 960 square meters of surface area intercept 480 continuous kilowatts of solar energy, but on average only half of it will be “beam” sunlight (undiffused) that can be focused. The SPU will produce 900 kilowatt-hours per sol of electricity and the equivalent of thermal energy. During dust storms its power output will fall to 18 kilowatt-hours.

11. MOONLET FUELING PLANT

The Moonlet Fueling Plant (MFP) is designed to extract volatiles from the chondritic bedrock of Phobos and Deimos, process them into hydrogen/oxygen and methane/oxygen fuels, liquefy them, and store them. The initial system includes a 1-tonne docking pad (in the center of the landing vehicle), two 1-tonne drills (deployed on opposite sides of the pad, and able to swing outward a meter from the pad), a 0.5-tonne volatile processing plant (built into the base of the pad, including a sabatier reactor, electrolysis unit, cryogenic refrigeration unit, and a fractionation tower), 2.5 tonnes of solar arrays, and two 0.5-tonne rovers. The plants are accompanied to Mars by the Lifters that propelled them from Gateway.

The system lands on the moon near the equator on the side facing away from Mars (the poles do not receive perpetual sunlight; the side toward Mars suffers from regular solar eclipses). The lander sinks harpoons into the regolith, using bursts from the reaction control system to keep the lander against the surface. The arrays are like the ones deployed on the Martian surface, but are longer; they unroll and are able to generate 30 kilowatts of power. The two drills deploy and drill up to 100 meters into Phobos. A microwave generator is lowered down the shafts to heat the chondrite, causing it to break down and release water vapor and possibly carbon gasses. The water vapor is captured, electrolyzed, and stored; later some of it is injected into the shafts to heat the chondrite further. Excess oxygen injected into the shaft will react with the carbon-rich rock to make carbon dioxide; excess hydrogen will react with it to make methane. The super-cold temperatures inside Phobos (way below the freezing point of water) will cause water to freeze cracks in the regolith closed. The fuel production complex should be able to generate as much as 60 tonnes of fuel per year (less, if there are leaks from the shaft or other inefficiencies). The two rovers can explore Phobos as well.

Once the Lifter is full, it can take off (gently, so as not to damage the unit) and fly to the ITV or anywhere else it is directed to. Full deployment of the fueling system may require astronauts.

12. AUTOMATED SURFACE EXPLORATION PACKAGE

The package consists of:

1. Large rover, 300 kg (which includes manipulator arms, stereoscopic cameras, meteorological sensors, a variety of geochemical analytical units, a microscope, a sample storage bin, fuel cell and small oxygen/methane tanks). The rover is shaped like an “A” frame on wheels and is 2 meters wide and 3 meters long, with its “A” frame 4 meters high. Solar panel area, total of 30 square meters; output is 1.8 kw at dawn and dusk, 1.2 kw at noon.

2. Small Rover, 100 kg (which includes manipulator arms, stereoscopic cameras, microscope, small sample storage bin, fuel cell, small oxygen-methane storage tanks, and 3 square meters of “A” frame solar panels able to make an average of 150 watts of power)

The two rovers always operate together, the larger rover serving as a base of operations, sample storage, and primary sample analysis site. The small rover goes out from it, explores, picks up samples, then returns to the large rover to drop off samples for analysis and for electrical recharge.

3. Sunwing (Solar-Powered Flying Wing, SPFW)

The Sunwing is based on two existing designs: the Helios (which actually flew to 90,000 feet on Earth) and the Martian Airborne Exploration Vehicle (MAEV, a University of Wichita Dept. of Aerospace Engineering design).

Vehicle Helios MAEV

Total mass 930 kg 80.5 kg

Wing mass 500? 28.0kg

Payload Mass 110/330 8.0 kg

Fuel cell mass 225 kg 6.0 (batteries)

Miscellaneous 30? 2 (avionics)

Motor Mass 70 10 kg

Wing length/width 75.3/3.6 30.5/1.2

Wing area (m2) 186.6 36.6 m2

Wing Loading 5 kg/m2 2 kg/m2

Takeoff velocity ? 31.4 m/sec

Max. velocity 75 m/sec 67 m/sec

Power takeoff/max v 503/1366 watts

Power output 37 kw (Earth) 1.3 kw (Mars)

Solar array area/mass 180/? 17.5 m2/26.3 kg

Note: Helios needs 10 kw in normal flight, which it could make on Mars

The Helios had a mass of 700 kg, including wings (area: 180 square meters, covered by solar panels [average mass, 3 kg/sq m, so wing mass is 530 kg, average electrical output on Mars 9 kw], propellers, motors, 100 kg; fuel cells dry, 70 kg). Cargo mass: up to 230 kg (including up to 120 kg H2/LOX). Typical speed: 30 km/hr but up to 270 km/hr.

From the above I conclude that a solar-powered biplane would have stronger wings (would probably need about 25% more wing surface because of reduced lift and increased drag) and if the cells are 30-35% efficient, it would have enough power. The Helios has about twice as much power on Earth as on Mars but functions in a 250% greater gravitational field. Sunwings would have a payload mass of 10-15% takeoff mass (unless the fuel cell mass were eliminated or shrank). Note that 200 kg of hydrogen/oxygen can store about 500 kilowatt-hours of power; a lot more than the wings can make per sol!

Sunwing-A specifications:

Mass: 825 kg without payload

Wings: biwings 270 square meters area, 60 meters long and 2.25 meters wide, 3 meters apart, staggered horizontally by 1 meter

Solar output (30% efficient panels): 900 kilowatt-hours per sol

Wing mass: 2.5 kg/m2 = 675 kg

Propellers and motors: 100 kg

Other: 50 kg

Payload: 450 kg (includes energy storage system)

Two energy storage systems in use:

1. methane/oxygen fuel cells with small VTOL rockets (total mass, 250 kg), OR

2. CO2 tank, rocket engines, beryllium heater [2000K, Isp 200 seconds], 100 kg; liquid CO2, up to 200 kg (delta-v, 0.35 km/sec = 1260 kmph, enough to glide several hundred kms). Vertical takeoff/landing capability

Sunwing-B is twice as large, achieved by making the forward wings fifty percent longer and wider (95 meters by 3.8 meters wide). Sunwing-C adds a two more wings (quadriplane) 2.5 meters above the others. Sunwing-D adds silane-powered rockets..

Sunwing-C “Solar Twin Otter”:

Payload: 1,000 kg cargo or six people with life support (similar to the Twin Otter, the basis of much arctic exploration)

Wings: four on top of each other (quadriplane), 2.5 meters apart, 95 meters tip to tip, 3.8 meters wide, area 360 square meters each (1440 square meters total)

Wing mass: 1440 x 1.5 = 2160 kg

Solar arrays: All of top wing and outer half of the other three (360 + 180 + 180 + 180 = 900 square meters @ 0.5 kg/sq meter (excluding electrical conversion equipment) = 450 kg (+2160 = 2610 kg)

Power output: 30% efficient conversion of sunlight, 5 kilowatt-hours per sol per square meter, use an area of 360 + 90 + 90 + 90 = 630 sq m x 5 = 3150 kilowatt hrs per sol = 128 continuous (24.6 hr) kilowatts

Power needed to move at 75 meters/sec (270 kmph, 167 mph) = 17 kw per tonne = 70 kw, so power output is plenty (or in the right ballpark)

Motors, propellers, etc.: 500 kg (+ 2610 = 3110 kg)

Power conversion equipment: 400 kg (+ 3110 = 3510 kg)

Wheels, misc. structure, pods: 300 kg (+3510 = 3810 kg)

Fuel Cells (4 kg/kw, 80 kw max): 320 kg (+ 3810 = 4130 kg)

Methane/oxygen tanks: 100 kg (+ 4110 = 4230 kg)

Rocket engines: 100 kg (+ 4210 = 4330 kg)

Methane/oxygen (1000 kw-hr @ 2 kw-hr/kg = 500 kg, plus delta-v of 180 m/sec = 300 kg): 800 kg (+ 4330 = 5130 kg). Note that half the 300 kg will be expended on take off and thus will not weigh down the vehicle in flight, and if the landing occurs during the day at a base the other half could come from the 500 kg of fuel used to store nighttime power)

Total nonpayload mass: 5130 kg

Note: if silane is available and is run through an external combustion engine massing 2 kg per kw, the fuel cell mass can be replaced by a 160 kg power plant and the propellant mass can be cut at least in half, saving 500 kg.

Three pods (right, central, left): 1/3 of fuel cell mass, tanks, rockets, propellant, power conversion in each: 2020/3 = 673 kg each. Right and left pods located on the second wing up from the bottom about 12 meters in from the wing tips and 35 meters from the central pod, where the 1,000 kg payload is located.

Central pod cabin/cargo bay: height, 2.5 meters; width, 2 meters bottom and top, 3 meters in middle; length, 5 meters; volume, 31 cubic meters.

13. CAMPER (4 tonnes empty mass)

The camper is a vehicle accommodating two persons designed to be pulled by a truck. It is 2.4 meters wide, 2.4 meters high, and 4 meters long. From front to back it has:

1. Central cabin, 3 meters long, with dinette (table and chairs on each side) on left side followed by sink and stove; on right side, a couch that became bunk beds for two and storage closets. Under the couch is the life support equipment. The front wall contains a hatch 1 meter wide and 1.5 meters high that can be docked to the truck via an airtight flexible tunnel.

2. Water cabin, 1 meter long, with a shower on the left, access corridor in the middle, and toilet/sink on the right side. A sliding door blocks the corridor. From the corridor, one must step up 0.8 meter to enter either the shower or the toilet/sink areas; the underfloor space is graywater storage and purification and life support. The corridor ends at an emergency door 1 meter wide and 1.5 meters high to the outside in the rear wall. Door comes equipped with a 0.8 meter telescoped pressure sleeve for connecting to another vehicle. A portable dustoff facility is attached to the rear of the vehicle as well.

14. TRUCK (2.5-4.0 tonnes)

The truck comes equipped with bulldozer blade (0.2), manipulator arm (0.1), rooftop crane (0.4) provisions (150 kg per person per month), internal fuel storage (0.5). Ground clearance: 0.8 meters. The vehicle comes with a frame of solar panels able to be raised 2 meters off the roof and able to generate 20 kilowatt-hours of electricity per sol, enough to run the life support at emergency levels. Dimensions: 2.5 meters long, 2.4 meters wide, 1.5 meters high (interior), 0.8 meter ground clearance. Trucks utilize methane/oxygen fuel cells built into the chassis. They have six wheels, each with its own electric motor and regenerative braking system. The system requires 0.25 to 0.5 kg of LOX/methane per kilometer per tonne of vehicle. A truck can keep two alive in an emergency.

15. DOCKING CABIN, 1.5 tonnes

The Docking Cabin is an inflatable structure 3 meters wide, 3 meters long, and 2.5 meters high usually including an airlock (1 by 2 meters) in front and airlock doors on the back and the two sides. It can be mounted on an open rover that can be driven by a person, controlled remotely, towed as a trailer, or can drive itself slowly. The docking cabin allows up to three vehicles to dock together to form a temporary “base” (they can also dock directly to each other, though). It has its own life support system and can be used for emergency accommodation or as a day-expedition base of operations. Docking cabins can also be attached to the Outpost, allowing vehicles to dock to it. Other docking cabins serve as large airlocks to allow parties to enter or leave; they can serve as a spacesuit donning facility or as industrial units with chemical or metallurgical units docked to them. Mass, 1.5 tonnes without equipment. Life support typically adds 100 kg.

16. MARS DOME, mass 14.5 tonnes

The Mars Dome is an inflatable kevlar hemisphere 32 meters in diameter with accompanying environmental control equipment. It includes four airlocks, one large enough to drive a pressurized rover through. Once inflated, it provides 804 square meters of space for walking, farming, and living; enough to feed eight to sixteen people. The Mars Dome is not flown to Mars until Columbus 4.

17. BIOME, mass 14 tonnes

A biome is an integrated system of housing, agriculture, and waste recycling in a single unit. It consists of a Kevlar dome 40 meters in diameter (surface area, 1250 square meters) rising 20 meters above the Martian surface and excavated at least 7 meters below the surface.

Within the dome are two crescent shaped transparent inflatable Kevlar structures filling the north and south sides of the circle, three stories (9 meters) high (including basement level), about 30 meters long, and 6-12 meters wide. Within each structure, housing is built of Martian materials (300 square meters per floor, 1,800 square meters total). The inflatable 1-tonne structure has an exterior curtain wall of vinyl panels to protect the Kevlar and a metal roof covered by two meters of Martian regolith, to provide radiation protection. The interior walls, of Martian sheetrock bolted onto a metal frame, mass 25 kg/sq. meter; each building has a total mass of 90-100 tonnes.

The east-west “valley” between the structures, called “the yard,” is park-like, with fruit trees, flowers, some vegetables, and small amounts of space for grass and clover. Its surface area is 600 square meters; it is 40 meters long and an average of 15 meters wide. The roofs above the inflatable structures are used for agriculture. They include a two-meter wide overhang and have a surface area of 375 square meters each. The roof-top agriculture occurs in “pans” two meters high and about ten meters square, each of which is watertight and filled with two meters of soil and/or water. Each biome can house, feed, and recycle the wastes of 16-24 people, depending on configuration of plants.

18. CONESTOGA (empty mass 6 tonnes)

The Conestoga is a four-person exploration vehicle. It is 2.4 meters wide, 2.4 meters high, and 8 meters long. From front to back it has:

1A. Driving cab, 2 meters deep, with two seats on the left and middle and a door on the right side. Cab has an airtight rear wall with hatch to central cabin. Cab can be depressurized for access to outside from the cab.

1B. Over the driving cab, a loft divided lengthwise accommodating two beds, opening on the central cabin.

2. Central cabin, 2.5 meters long, with dinette (table and chairs on each side) on left side followed by sink and stove; on right side, a couch and storage. Under the couch is the life support equipment.

3. Water cabin, 1 meter long, with a shower on the left, access corridor in the middle, and toilet/sink on the right side. The door to the central cabin is not airtight; the door to the rear cabin is. From the corridor, one must step up 0.8 meter to enter either the shower or the toilet/sink areas; the underfloor space is graywater storage and purification and life support.

4A. Rear cabin, 2.5 meters, with space suit storage, EVA equipment, fold-up table, fold-up chairs, science gear. The room has an airtight hatch between it and the water cabin and a rear door. After suiting up, the room can be depressurized, thereby serving as an airlock. Rear door comes equipped with a 0.8 meter telescoped pressure sleeve for connecting to another vehicle. It has its own life support system.

4B. Two loft beds over the rear cabin. The loft can be raised to provide better headroom for daytime use of the cabin.

The Conestoga comes equipped with stronger bulldozer blades. The vehicle is too long to be flown to Mars ready to operate; rather, the chassis must be extended its full length and bolted together. The pressure cabin, made of advanced plastics, can fold up and be inflated on arrival. Water is stored in tanks inside the pressure shell on the ceiling, thereby providing radiation shielding. Oxygen and methane are stored in tanks outside on the roof. The vehicle comes with a frame of solar panels able to be raised 2 meters off the roof and able to generate 30 kilowatt-hours of electricity per sol, enough to run the life support at emergency levels. A portable dustoff facility is attached to the rear of the vehicle as well.

19. MOBILHAB, (Mobile Hab) mass 8 tonnes (2 tonnes from Earth)

The Mobilhab is a six- to eight-person exploration vehicle. It is 2.4 meters wide, 5 meters (two stories) high, and 8 meters long. From front to back it has:

I. First floor:

1B. Over the driving cab, a loft divided lengthwise accommodating two beds, opening on the central cabin.

2. Central cabin, 2.5 meters long, with dinette (table with chairs on each side) on left side followed by sink and stove; on right side, a couch and a ladder/ceiling hatch to the second story. Under the couch is the life support equipment.

3. Water cabin, 1 meter long, with a shower on the left, access corridor in the middle, and toilet/sink on the right side. The door to the central cabin is not airtight; the door to the rear cabin is. From the corridor, one must step up 0.8 meters to enter either the shower or the toilet/sink areas; the underfloor space is graywater storage and purification and life support.

4B. Storage over part of the ceiling of the rear cabin, and a ladder and ceiling hatch providing access to the second story.

II. Second story:

1A. Front cabin, 2 meters deep, with a private cubicle on the right and one on the left (bed on top; desk, lockers, underneath).

2. Central cabin, 2.5 meters long, with science and engineering equipment and life support equipment. A shaft opens to the lower level. Two fold-up beds allow use as accommodation.

4A. Rear cabin, 2.5 meters, with with a private cubicle on the right and one on the left (bed on top; desk, lockers, underneath). Cabin has its own life support system. A shaft opens to the lower level.

The Mobilab must be assembled on Mars from a locally made pressure shell and imported equipment. Water is stored in tanks inside the pressure shell on the ceiling, thereby providing some radiation shielding. Oxygen and methane are stored in tanks outside on the roof. The vehicle comes with a frame of solar panels able to be raised 2 meters off the roof and able to generate 30 kilowatt-hours of electricity per sol, enough to run the life support at emergency levels. A portable dustoff facility is attached to the rear of the vehicle as well.