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1972: NASA hell of a year (15)
Decision point - and the winner is...

“As the name implies Helios is a scaled-up Gemini with a crew of three to nine.

The crew module extends the Gemini B exterior cone to back 13 ft diameter heat shield. The crew module could be a minimal modification of Gemini B or a more advanced design.

Basic mission is space station logistic support, typically entailing low earth orbits of 100-300 nm at 28-30° inclination and a system availability date of 1973 to 1975.

The program objective is space station logistic capability at minimum cost. Land landing in the continental U.S. is the preferred recovery option, with water recovery capability to be retained.

Recovery of the crew module is by parawing and a three skid landing gear extends from the bottom of the crew module. Design and analysis of the parawing and landing mode were accomplished by Northrop-Ventura under a subcontract.

Launch vehicles considered included the Titan IIIM, the Saturn IB, and the Saturn INT-20 or S-IC / S-IVB.

Orbital cargo delivery capability varies according to the launcher and inclination, from 3000 to 65 000Ibs. The design return cargo capability is 2,000 lbs.

Several recovery options were considered such as externally deployed parawing and bicycle landing gear supplemented by outriggers. Two-man-Gemini’s ejection seats and hatches have been deleted. The crew enters Big Gemini crew module through two large hatches set above the passenger section.

The crew compartment is flanked with a large, pressurised cylindrical cargo section. At the aft end a pilot's station is equipped with controls and windows for manual docking with the space station.

Orbital transfer, rendezvous and docking, attitude control and deorbit propulsion functions are all performed by a single liquid propellant system.
Launch escape is provided by an Apollo-type solid rocket escape tower mounted on the spacecraft nose.

A flight test Min-Mod vehicle could be launched 37 months from go-ahead and that the first operational vehicle could be launched 43 months from go-ahead. The Advanced Helios schedule add three months to these figures.

Parawing technology is considered "the pacing Item in the development program." Parawings have not been demonstrated with payloads above 6,000 lbs at this point, well below the 18,000 lbs required for Helios . Despite that McDonnell Douglas is reasonably certain that the required capability could be achieved.

“Cost estimations are $1.5 billion for developing the Big Gemini capsule and its launcher, along with approximately $2.25 billion in recurring operational costs, for a total of $3.75 billion.”

“From 1967 onwards Big Gemini has grown from a logical need outside Apollo – the need for a twelve-man ferry to a space station in the early 70’s. The Apollo CSM maximum capacity was six men at best, while the (now cancelled) shuttle promises lot of technical uncertainties, making it unlikely before 1977 at best.”

(excerpt from ENLARGED GEMINI TO REPLACE CANCELLED SHUTTLE, Flight International, July 4 1972)



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