d.ifferent weapon types, some mrlti-purpose, others intended for special obJectives" This is also covered- to some er:tent in what fo11olls, Warhead. d.esipn and characteristic s 73, The single most outstanding feature in warhead d.eveloluent up to now has been the red.uction of slze and veight in rel-ation to yield. This process has nade possible the d.es1gn of multiple uarheads on stlategic nissiles, as well- as some of the weapons denoted as tactical. ?l+" The bonbs that l"evefl-ed- Hiroshina and. Nagasaki weighed. about 5 tons each and could not have been d.elivered by any other carriers than heaw bonbers. By comparison, the Poseidon submarine-launched nissi"le, lrith a total throw-iteiGht of f ,OOO ke., earries 10 varhcad.s, each of three times the yield of lliroshina bonb ' Tnis represents a l-5O-fofd increase in the yicld-to-veight ratio' 7r" Another example is Siven by the nuclear artillery sheLls mentioned' in cnapter II , which denonstrabe that it is possible to buifd nuclear explosives so si.rafl that the outer d.ia;areter of the casing is -155 r.rlr. J and so li8ht that the explosive, its a.sscciatecl safecy, ar..rirrE and fjring *.cchanisrns .rnd the n(-tr.l casiu: altogether do not we iilh :r."rch more than 40 kg., -"/hich is the approximate ueia'ht of a conventional 155 rnrn, she1r.!,/ 35 / 392 English Annex fagt Jr) 7b. From ilvaifable data on MIRVs and other devices, it seerns 1ike1y that, at -Lcasr in the United Stares, bhis I'niniatur i zat ion " of nuc.Iear uarheads is now, in sone applications" close to the limits set by the .Iaws of physics. Other nuclear- weapon States rr:)ay be a-pproaehing - or alreafir have acbieved. - the sa.me levels of ^^*-r-l.,arc h,-+ +har, --v alq^ nrrt lhFiT nrinriti^c ,lj efFr.-nj-lw Ac hes been indicated earlier, the Soviet Union has developed MIRV technology.
**Analysis**
The text appears to be discussing the development and design of nuclear weapons, specifically focusing on the reduction of size and weight while maintaining or increasing yield. The examples provided, such as the Poseidon submarine-launched missile and nuclear artillery shells, illustrate the advancements in miniaturization of nuclear warheads. The text also mentions the development of MIRV technology, which suggests a focus on military technology.

**Category**
Science and technology, Industry