Editing Smiling Buddha (section)

== Development ==
With two reactors operational in early 1960s, Bhabha was involved in learning and development of know-how to manufacture nuclear weapons. The atomic energy act was amended in 1962 to give far more control to the [[Government of India|central government]]. Bhabha was also aggressively lobbying for nuclear weapons and made several public speeches on the matter. He also estimated that a nuclear device with a 10 [[kiloton|kt]] yield would cost US$350,000. The reactors were not producing fuel at the expected rate and with Nehru's death in 1964, the programme slowed down.<ref name="Program">{{cite web|title=On to Weapons Development, 1960–67|url=http://nuclearweaponarchive.org/India/IndiaWDevelop.html|publisher=Nuclear Weapon Archive|access-date=14 January 2013|date=30 March 2001}}</ref> The incoming prime minister [[Lal Bahadur Shastri]] gave approval for the Subterranean Nuclear Explosion Project in 1964 under Bhabha's insistence. However, Shastri did not want to commit to a weapons test yet, and later appointed physicist [[Vikram Sarabhai]] as the head of the nuclear programme. Because of Sarabhai's non-violent [[Gandhian]] beliefs, he directed the programme towards peaceful purposes rather than military development.<ref name="Kanavi">{{cite web|last=Kanavi|first=Shivanand|title=How Indian PMs reacted to nuclear bombs|url=https://www.rediff.com/news/slide-show/slide-show-1-an-interview-with-k-subrahmanyam/20110210.htm|work=[[Rediff.com]]|access-date=2 April 2024|archive-date=15 November 2019|archive-url=https://web.archive.org/web/20191115120835/https://www.rediff.com/news/slide-show/slide-show-1-an-interview-with-k-subrahmanyam/20110210.htm|url-status=live}}</ref> Meanwhile, the design work on the bomb proceeded under physicist [[Raja Ramanna]], who continued the nuclear weapons technology research after Bhabha's death in 1966.<ref name="Program"/>

[[File:Trombay.jpg|thumb|APSARA reactor and plutonium reprocessing facility at [[Bhabha Atomic Research Centre|BARC]] as photographed by a US satellite on 19 February 1966]]

After Shastri's death in 1966, [[Indira Gandhi]] became the prime minister and work on the nuclear weapons programme resumed. [[Homi Sethna]], a chemical engineer, was put in charge of plutonium development. The project for the design and manufacturing of the nuclear device employed just 75 scientists because of the secret nature of the project.<ref name="Kanavi"/> Ramanna led the project with [[P. K. Iyengar]] serving as his deputy and the leadership team also included Sethna and Sarabhai.<ref>{{cite web|url=http://www.nti.org/facilities/861/|title=Purnima I-II-III|date=1 September 2003|access-date=8 September 2014|work=[[Nuclear Threat Initiative]]|archive-url=https://web.archive.org/web/20140909004708/http://www.nti.org/facilities/861/|archive-date=9 September 2014}}</ref> The weapons programme was directed towards the production of plutonium rather than uranium and then in 1969, enough plutonium had been accumulated for the production of a single nuclear bomb.<ref name="Program"/> In 1968–69, Iyengar led a team to the Soviet Union and toured the nuclear research facilities at [[Dubna]]. Upon his return to India, Iyengar set about developing a plutonium fueled [[fast breeder reactor]] named ''Purnima'' under Mahadeva Srinivasan. In 1969, [[Rajagopala Chidambaram|R. Chidambaram]] was engaged for researching the use of plutonium.<ref name="Bomb">{{cite web|title=India's First Bomb: 1967-1974|url=https://nuclearweaponarchive.org/India/IndiaFirstBomb.html|date=30 March 2001|publisher=Nuclear Weapon Archive|access-date=2 April 2024}}</ref><ref>{{cite book|last=Richelson|first=Jefferey T|author-link=Jeffrey T. Richelson|title=Spying on the Bomb: American Nuclear Intelligence from Nazi Germany to Iran and North Korea|date=March 1999|publisher=WW Norton|page=[https://archive.org/details/spyingonbombamer00rich/page/233 233]|isbn=978-0-393-05383-8|url=https://archive.org/details/spyingonbombamer00rich/page/233}}</ref> 

Simultaneous work on the fabrication of the bomb core and [[implosion-type nuclear weapon|implosion]] design was conducted by teams led by physicist [[V. S. Ramamurthy]]. The detonation system development began in April 1970 with [[Pranab R. Dastidar]] collaborating with [[Waman Dattatreya Patwardhan|W. D. Patwardhan]] at the [[High Energy Materials Research Laboratory]] (ERDL) of the [[Defence Research and Development Organisation]] (DRDO). In July, physicist [[Basanti Dulal Nagchaudhuri|B. D. Nagchaudhuri]] was appointed as the scientific adviser to the [[Minister of Defence (India)|Defense Minister]] and as Director of the DRDO.<ref name="Bomb"/> Nagchaudhuri and Ramanna worked together to recruit the team and set up the requirements necessary for a nuclear weapon test. [[Terminal Ballistics Research Laboratory]] (TBRL) of the DRDO developed the explosive lenses for the implosion system. Srinivasan and K. Subba Rao were tasked with developing fission models and prediction of the test's efficiency. In April 1971, Nagchaudhuri appointed N. S. Venkatesan as the new Director of TBRL to help develop the implosion system. [[Dr. V. K. Iya|V.K. Iya]] was in charge of developing the [[neutron]] initiator system. In the same year, Sethna succeeded Sarabhai as the chairman of the Atomic Energy Commission.<ref name="Bomb"/> 

In December 1971, during the [[Indo-Pakistani War of 1971|Indo-Pakistani War]], the U.S. government sent a [[carrier battle group]] led by the {{ship|USS|Enterprise|CVN-65}} into the [[Bay of Bengal]] in an attempt to intimidate India. The Soviet Union responded by sending its own naval force to deter the U.S. from involving militarily. This event is indicated as a reason for India's pursuance of the nuclear programme.{{sfn|Perkovich|1999|p=165}} After India gained military and political initiative over Pakistan in the [[Indo-Pakistani war of 1971]], the work on building a nuclear device continued. The hardware began to be built in early 1972 and the Prime Minister authorised the development of a nuclear test device in September 1972.{{sfn|Perkovich|1999|p=172}}