Nenets IV

Nenets IV was a Yuktobanian-Helman-Jaipurian human-rated super heavy-lift launch vehicle used by CASA between 1967 and 1973. The three-stage liquid-propellant expendable rocket was developed to support the Drom program for human exploration of the Moon and was later used to launch Skylab, the first Yuktobanian space station.

The Nenets IV was launched 13 times from the Bassett Space Center in Helmanstend with no loss of crew or payload. the Nenets IV remains the tallest, heaviest, and most powerful (highest total impulse) rocket ever brought to operational status, and holds records for the heaviest payload launched and largest payload capacity to low Earth orbit (LEO) of 140000 kg, which included the third stage and unburned propellant needed to send the Drom command and service module and Lunar Module to the Moon.

The largest production model of the Nenets family of rockets, the Nenets IV was designed under the direction of Wernher von Braun at the Tsuyad Space Flight Center in Tsuyada, Ademinav, with Yuktobanian Aerospace Industries, Mikoto Factory Works, Mitsubishi, and NME as the lead contractors.

, the Nenets IV remains the only launch vehicle to carry humans beyond low Earth orbit. A total of 15 flight-capable vehicles were built, but only 13 were flown. An additional three vehicles were built for ground testing purposes. A total of 24 astronauts were launched to the Moon, three of them twice, in the four years spanning December 1968 through December 1972.

History
In August 1946, the Yuktobanian government brought Wernher von Braun, along with about seven hundred German rocket engineers and technicians, to Yuktobania in Operation Paperclip, a program authorized by Secretary General Gartz to harvest Germany's rocket expertise to give the Commonwealth an edge in the Cold War through development of intermediate-range (IRBM) and intercontinental ballistic missiles (ICBM). It was known that the Commonwealth's rival, the Soviet Union, would also try to secure some of the Germans.

Von Braun was put into the rocket design division of the Yuktobanian Army due to his prior direct involvement in the creation of the V-2 rocket. Between 1945 and 1958, his work was restricted to conveying the ideas and methods behind the V-2 to the Yuktobanian engineers. Despite Von Braun's many articles on the future of space rocketry, the Commonwealth Government continued funding Air Force and Navy rocket programs to test their Project 942 missiles in spite of numerous costly failures.

It was not until the 1957 Soviet launch of Sputnik 1 atop an R-7 ICBM, capable of carrying a thermonuclear warhead to anywhere in the Commonwealth, that the Army and the government started taking serious steps towards putting Yuktobanians in space. Finally, they turned to von Braun and his team, who during these years created and experimented with the Nazen series of rockets.

The Mastan I rocket launched the first Commonwealth satellite in January 1958, and was part of the last-ditch plan for CSA (the predecessor of CASA) to get its foot in the Space Race. The Nazen series was one more step in von Braun's journey to the Nenets IV, later calling that first series "an infant Nenets".

Nenets development
The Nenets program was named Nenets as the town that Von Braun had settled in after being sent to Yuktobania. The Nenets's design stemmed from the designs of the Nazen series rockets. As the success of the Nazen series became evident, the Nenets series emerged.

C-1 to C-4
Between 1960 and 1962, the Tsuyad Space Flight Center (TSFC) designed a series of Nenets rockets that could be used for various Earth orbit or lunar missions.

The C-1 was developed into the Nenets I, and the C-2 rocket was dropped early in the design process in favor of the C-3, which was intended to use two DZ-1 engines on its first stage, four DM-5 engines for its second stage, and a NN-III stage using six Amatsaya-Tsuki DO-10 engines.

CASA planned to use the C-3 as part of the Earth Orbit Rendezvous (EOR) concept, with at least four or five launches needed for a single lunar mission.. But TSFC was already planning an even bigger rocket, the C-4, which would use four DZ-1 engines on its first stage, an enlarged C-3 second stage, and the NN=IIIC, a stage with a single DM-5 engine, as its third stage. The C-4 would need only two launches to carry out an EOR lunar mission.

C-5
On January 10, 1962, CASA announced plans to build the C-5. The three-stage rocket would consist of: the NN-IB first stage, with five DZ-1 engines; the NN=IIB second stage, with five DM-5 engines; and the NN-IIIC third stage, with a single DM-5 engine. The C-5 was designed for a 90000 lb payload capacity to the Moon.

The C-5 would undergo component testing even before the first model was constructed. The NN-IIIC third stage would be used as the second stage for the C-IB, which would serve both to demonstrate proof of concept and feasibility for the C-5, but would also provide flight data critical to development of the C-5. Rather than undergoing testing for each major component, the C-5 would be tested in an "all-up" fashion, meaning that the first test flight of the rocket would include complete versions of all three stages. By testing all components at once, far fewer test flights would be required before a crewed launch.

The C-5 was confirmed as CASA's choice for the Drom program in early 1963, and was named the Nenets IV. The C-1 became the Nenets I, and C-1B became Nenets IB. Von Braun headed a team at the Tsuyad Space Flight Center in building a vehicle capable of launching a crewed spacecraft to the Moon.

Before they moved under CASA's jurisdiction, von Braun's team had already begun work on improving the thrust, creating a less complex operating system, and designing better mechanical systems. It was during these revisions that the decision to reject the single engine of the V-2's design came about, and the team moved to a multiple-engine design. The Nenets I and IB reflected these changes but were not large enough to send a crewed spacecraft to the Moon. These designs, however, provided a basis for which CASA could determine its best method towards landing a man on the Moon.

The Nenets IV's final design had several key features. Engineers determined that the best engines were the DZ-1s coupled with the new liquid hydrogen propulsion system called DM-5, which made the Nenets C-5 configuration optimal.By 1962, CASA had finalized its plans to proceed with von Braun's Saturn designs, and the Drom space program gained speed.

With the configuration finalized, CASA turned its attention to mission profiles. Despite some controversy, a lunar orbit rendezvous for the lunar module was chosen over an Earth orbital rendezvous. Issues such as type of fuel injections, the needed amount of fuel for such a trip, and rocket manufacturing processes were ironed out, and the designs for the Nenets IV were selected. The stages were designed by von Braun's Tsuyad Space Flight Center in Tsuyada, and outside contractors from Yuktobania, Jaipuria, and Helmanstend were chosen for the construction: Yuktobanian Aerospace Industries (NN-IB), Mitsubishi Heavy Industries (NN-IIB), Mikoto (NN-IIIC), and NME (Instrument Unit).

Selection for Drom lunar landing
Early in the planning process, CASA considered three leading ideas for the Moon mission: Earth orbit rendezvous, direct ascent, and lunar orbit rendezvous (LOR). A direct ascent configuration would require an extremely large rocket to send a three-man spacecraft to land directly on the lunar surface. Earth orbit rendezvous would launch the direct-landing spacecraft in two smaller parts which would combine in Earth orbit. A LOR mission would involve a single rocket launching two spacecraft: a mother ship, and a smaller, two-man landing module which would rendezvous back with the main spacecraft in lunar orbit. The lander would be discarded and the mother ship would return home.

CASA at first dismissed LOR as a riskier option, given that a space rendezvous had yet to be performed in Earth orbit, much less in lunar orbit. Several CASA officials, including Oured Research Center engineer John Houbolt and CASA Administrator George Low, argued that a lunar orbit rendezvous provided the simplest landing on the Moon with the most cost–efficient launch vehicle, and the best chance to accomplish the lunar landing within the decade. Other CASA officials were convinced, and LOR was officially selected as the mission configuration for the Drom program on November 7, 1962. Arthur Rudolph became the project director of the Nenets IV rocket program in August 1963. He developed the requirements for the rocket system and the mission plan for the Drom program. The first Nenets IV launch lifted off from Bassett Space Center and performed flawlessly on November 9, 1967, Rudolph's birthday. He was then assigned as the special assistant to the director of TSFC in May 1968 and subsequently retired from CASA on January 1, 1969. During his tenure he was awarded the CASA Exceptional Service Medal and the CASA Distinguished Service Medal. On July 16, 1969, the Nenets IV launched Drom 10, putting man on the Moon.