Von Braun Mars 1956 Credit - © Mark Wade

Von Braun's Mars expedition presented in the 1956 book he co-authored with Willy Ley, The Exploration of Mars, was vastly reduced in scope from the 1952 version. Obviously facing incredulity at the awesome scope of the first expedition concept - 70 crew aboard ten spacecraft - Ley and Von Braun cut the expedition to just two ships, 12 crew, and cut the mass of those ships in half compared to the earlier designs.

The Passenger Ship, equipped with a 7.9 m diameter personnel sphere, provided crews quarters over the long mission. The Cargo Ship again carried the Landing Boat, but this time the 195 metric tons of contingency supplies were eliminated and the Boat itself reduced from 200 metric tons to 177 metric tons.

No fundamental new calculations were made, but an efficiency was added to the mission profile by having the Passenger Ship brake into a high earth orbit on return, which saved considerable propellant and proportionately decreased the mass all along the sequence. Still, 400 launches of a reduced-size three-stage shuttle were required to provide the material and propellant for the two ships. However 353 of these would be cargo-only flights, another improvement in the plan.

The thrust of the ship's engines was doubled, making for a shorter 948 second Trans-Mars Injection burn, and reducing losses on the departure maneuver. During the 250 day coast 3 of the 12 crew would take up quarters in the Mars Landing Boat aboard the Cargo Ship, giving the 9 crew remaining in the Passenger Ship a little elbow room. The passenger ship was equipped with a 7.9 m 26 ft diameter personnel sphere, to provide the crew quarters during the long voyage to Mars and back.

The profile of the mission at Mars remained as before. Both ships brake into a 1000 km Mars equatorial orbit. Nine of the crew take the Landing Boat down to the Martian surface for a 400-day surface expedition, while three stay aboard the Passenger Ship to study the planet from orbit and provide communications relay with earth. The prime landing site was considered to be Margaritifer Sinus.

The nine on the surface expedition then rocket into Mars orbit on an ascent stage, half the size of the original design for 25 crew. They rendezvous and dock with the passenger ship, and then return with the other three crew to earth on a 268 day return journey. An important difference was that the passenger ship braked into a high 90,320 km earth orbit at the end of the three year mission. From here a Relief Ship had to be sent from Earth to recover the crew and the Mars samples and bring them down to the 1730 km orbit where a shuttle waited to take them back to earth.

• Summary: Reduced-scale version of 1952 Mars mission design
• Propulsion: Nitric acid/Hydrazine
• Braking at Mars: propulsive
• Mission Type: conjunction
• Split or All-Up: all up
• ISRU: no ISRU
• Launch Year: 1970
• Crew: 12
• Mars Surface payload-metric tons: 49
• Outbound time-days: 250
• Mars Stay Time-days: 445
• Return Time-days: 268
• Total Mission Time-days: 963
• Total Payload Required in Low Earth Orbit-metric tons: 3400
• Total Propellant Required-metric tons: 3280
• Propellant Fraction: 0.96
• Mass per crew-metric tons: 283
• Launch Vehicle Payload to LEO-metric tons: 14
• Number of Launches Required to Assemble Payload in Low Earth Orbit: 400
• Launch Vehicle: Von Braun 1956

Crew Size: 12. Design Life: 1000. Mass: 3,400,000 kg (7,400,000 lb).

• 1956 Von Braun Passenger Ship.  Class: Manned. Type: Mars Orbiter. Destination: Mars. Nation: USA. Manufacturer: Von Braun.

  The 1956 version of Von Braun's Mars design was slashed by 50% in mass, while the number of passengers was increased from 10 to 12. The passengers would be housed in a 7.9-m-diameter sphere during the 963 day mission to Mars, in Mars orbit, and back to earth. The Passenger Vessel would perform four major maneuvers: Trans-Mars Injection, Mars Orbit Insertion, Trans-Earth Injection and Earth Orbit Insertion.

  The crew quarters were divided in three decks: an upper control deck, with a transparent dome for the navigator to take star sightings; and two decks of living quarters. A fireman's pole ran through the center for use by the crew in getting around the ship in zero gravity. At the bottom of the passenger sphere was an airlock for access to space. The internal atmosphere would be oxygen/helium, at 0.54 atmospheres pressure.

  Crew Size: 12. Design Life: 1000. Length: 37.00 m (121.00 ft). Basic Diameter: 7.90 m (25.90 ft). Maximum Diameter: 25.40 m (83.30 ft). Mass: 1,700,000 kg (3,700,000 lb). Main Engine Thrust: 3,530.000 kN (793,570 lbf). Main Engine Propellants: nitric acid/hydrazine. Main Engine Propellants: 1,640,000 kg (3,610,000 lb). Main Engine Isp: 297 sec. Spacecraft delta v: 9,000 m/s (29,500 ft/sec).

• 1956 Von Braun Cargo Ship.  Class: Manned. Type: Mars Orbiter. Destination: Mars. Nation: USA. Manufacturer: Von Braun.

  Using the same basic systems as the Passenger Ship, the Cargo Ship would substitute a 177 metric ton Landing Boat for the surface expedition in place of the Passenger Sphere and propellant for the return home. The Cargo Ships would be left behind in Mars orbit.

  Design Life: 1000. Length: 62.00 m (203.00 ft). Basic Diameter: 7.90 m (25.90 ft). Maximum Diameter: 16.00 m (52.00 ft). Mass: 1,700,000 kg (3,700,000 lb). Payload: 177,000 kg (390,000 lb). Main Engine Thrust: 3,530.000 kN (793,570 lbf). Main Engine Propellants: nitric acid/hydrazine. Main Engine Propellants: 1,245,500 kg (2,745,800 lb). Main Engine Isp: 297 sec. Spacecraft delta v: 5,600 m/s (18,300 ft/sec).

• 1956 Von Braun Landing Boat.  Class: Manned. Type: Mars Lander. Destination: Mars. Nation: USA. Manufacturer: Von Braun.

  The 1956 modification of Von Braun's Landing Boat design was reduced in mass by 12%, and the wingspan by 10%. The profile was the same, except that the ascent stage was only half the size to take the crew of 9 back to Mars orbit (as opposed to 25 in the original design). This allowed a much larger net payload to be landed on the surface, necessary since this was a single-ship mission. The enormous glider would land on Mars horizontally on skids at a location judged to be flat enough from orbital survey. The forward part of the fuselage, which formed the ascent stage, would be winched vertically for the return to the mother ships in Mars orbit after 400 days on the surface.

  Since there was no back-up to the passenger ship, and quarters were cramped there, three crew members would stay aboard the cut-rate Landing Boat during the coast from earth to mars. This Landing Boat design was equipped with five rocket engines. They would fire first to deorbit the glider from the 1000 km altitude orbit of the Cargo Ship which had conveyed it to Mars. The descent profile was the same as that calculated in 1948. 9 of the expedition's 12 crew would be sent to the surface on the landing boat. After raising the forward part of the fuselage - the ascent stage - to a vertical position in case of the need for an emergency return, they would set up their Mars base. Payload included 17 metric tons of consumables and 32 metric tons of equipment, including a tractor with pressurized quarters for extended surveys of the surface, a 6-m diameter inflatable pressurized tent for surface quarters, and scientific equipment.

  At the appropriate time, the crew would lift-off in the ascent vehicle and rendezvous with the seven passenger ships in orbit. The ascent stage would have a launch mass of 69 metric tons, half that of the original design. The burn into an elliptical transfer orbit and the circularization burn near the passenger ship would require 56.4 metric tons of propellant. Transfer of the 9 astronauts and 2.5 metric tons of material returned from the surface would be done between the ascent vehicle and the passenger ship using the Passenger Ship's 3.5 metric ton space boat. The ascent stage, abandoned in Mars orbit, would have an empty mass of 12.5 metric tons.

  Crew Size: 9. Design Life: 750. Length: 22.00 m (72.00 ft). Basic Diameter: 4.10 m (13.40 ft). Maximum Diameter: 5.70 m (18.70 ft). Span: 137.00 m (449.00 ft). Mass: 161,000 kg (354,000 lb). Payload: 49,000 kg (108,000 lb). Main Engine Thrust: 1,470.000 kN (330,460 lbf). Main Engine Propellants: nitric acid/hydrazine. Main Engine Propellants: 56,400 kg (124,300 lb). Main Engine Isp: 297 sec. Spacecraft delta v: 4,100 m/s (13,400 ft/sec).

• Portree, David S. F., Humans to Mars: Fifty Years of Mission Planning, 1950 - 2000, NASA Monographs in Aerospace History Series, Number 21, February 2001. Excellent overview of American plans for sending men to Mars.

• Miller, Ron, The Dream Machines, Krieger, Malabar, Florida, 1993. ISBN: 0894640399. Sensational chronological roundup of text, photos, and sketches of virtually every spacecraft and launch vehicle design every conceived but never built. A gold mine for space-struck baby boomers. More at amazon.com...