Indian nukes and missiles are no more indigenous than Pak nukes and missiles missiles.
APJ Abul Kalam is credited with designing India's first satellite launcher SLV3. Its design is virtually identical to the American Scout rocket used in the 1960s. According to the details published in the Bulletin of Atomic Scientists, Abul Kalam spent four months in training in the United States in 1963-1964. He visited NASA's Langley Research Center in Virginia, where the U.S. Scout rocket was conceived, and the Wallops Island Flight Center on the Virginia coast, where the Scout was being flown. Soon after Abul Kalam's visit, India requested and received detailed technical reports on the Scout's design, which was unclassified.
US Scout and India's SLV3 are both 23 meters long, use four similar solid-fuel stages and "open loop" guidance, and lift a 40-kilogram payload into low earth orbit. The SLV's 30-foot first stage later became the first stage of the Agni.
The United States was followed by others. Between 1963 and 1975, more than 350 U.S., French, Soviet, and British sounding rockets were launched from India's Thumba Range, which the United States helped design. Thumba's first group of Indian engineers had learned rocket launching and range operation in the United States.
India's other missile, the "Prithvi" (earth), which uses a liquid-propelled motor to carry a one-ton payload 150 miles, resembles the widely sold Soviet Scud-B. Indian sources say that the Agni's second stage is a shortened version of the Prithvi, according to Gary Milhollin of the Wisconsin Project.
India's nuclear program would not have advanced without a lot of help from Canadians that resulted in Indian copies of Canadian reactors to produce plutonium for its nuclear bombs.
India conducted its first atomic bomb test in 1974. Indians used 40 MW Canadian Cirus reactor and U.S. heavy water both imported under guarantees of peaceful use and used them openly to make plutonium for its 1974 nuclear blast.
In 1972, Canadian-built 100 MWe Rajasthan-1 nuclear power reactor became operational, serving as the model for later unsafeguarded reactors. Another Rajasthan unit started operating in 1980 and two units in 2000. In 1983, India's 170 MW Madras-1, a copy of Canadian Rajhastan-1 reactor, became operational. A second Madras unit followed in 1985. According to the Risk Report Volume 11 Number 6 (November-December 2005), the heavy water and other advanced materials and equipment for these plants were smuggled to India from a number of countries, including the USSR, China and Norway, according to The Bulletin of Atomic Scientists. Some of the firms, such as West German firm Degussa, were caught and fined by the United States for re-exporting to India 95 kg of U.S.-origin beryllium, usable as a neutron reflector in fission bombs.
Haq's Musings: India's "Indigenous" Copies of Foreign Nukes, Missiles