NEW LUNAR ROCKET

The new rocket, the 8K78, was a key development. The 8K78 became a cornerstone of the Soviet space programme as a whole, not just the moon programme and versions were still flying over 40 years later, over 220 being flown. The following were the key elements:

• Improvements to the RD-108 block A and RD-107 block BVGD stages of the R-7, with more thrust, higher rates of pressurization and larger tanks, developed by Glushko’s OKB-453.

• A new upper stage, the block I, developed with Kosberg’s OKB-154.

• A new fourth stage, the block L, designed within OKB-1.

• New guidance and control systems, the I-100 and BOZ.

In a new approach, the first three stages would put the block L and payload in Earth orbit. Block L would circle the Earth once in what was called a parking orbit before firing out of Earth orbit for the moon. With the Ye-1 to -4 series, a direct ascent was used, the rocket firing directly to the moon. The problem with direct ascent was that even the smallest error in the launch trajectory, even from early on, would be magnified later. By contrast, parking orbit would give greater flexibility in when and how rockets could be sent to the moon. The course could be recalculated and readjusted once in Earth orbit before the command was given. Parking orbit also enabled a much heavier payload to be carried.

The principal disadvantage – no one realized how big it would turn out to be – was that the engine firing out of parking orbit required the ignition of engines that had been circling the Earth in a state of weightlessness for over an hour. This was where

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block L came in. Block L was designed to work only in a vacuum, coast in parking orbit and then fire moonward. A device called the BOZ (Blok Obespecheyna Zapushka) or Ignition Insurance System would guide the firing system toward the moon. Block L was 7.145 m long, the first Soviet rocket with a closed-stage thermo­dynamic cycle, with gimbal engines for pitch and yaw and two vernier engines for roll. The new third stage, block I, was based on an intercontinental ballistic missile design called the R-9. A new orientation system for blocks I and L, called the I-100, was devised by Scientific Research Institute NII-885 of Nikolai Pilyugin.

The new 8K78 rocket, including block L, was built in some haste. Block L was ordered in January I960 and the blueprints approved in May. The first two stages, with block I but without block L, were fired in suborbital missions from January onward. Block L was first tested aboard Tupolev 104 aircraft, designed to simulate weightlessness, in summer 1960. The first all-up launchings took place in October 1960, when two probes were fired to Mars, both failing at launch. Two Venus launches were made in February 1961, one being stranded in Earth orbit but the second one getting away successfully. But the worst period in the development phase was still to come. Three Venus probes in a row failed in August/September 1962, all at launch. Of three Mars probes in October/November 1962, only one left parking orbit. Blocks A and B failed once, block I three times and block L four times. The Americans later published the list of all these failures (this took the form of a letter to the secretary general of the United Nations from ambassador Adlai Stevenson on 6th June 1963), but some people assumed they were making them up, for no country could afford so many failures and still keep on trying.