DÃÂ©tente is the name given to the period between 1963 and 1979, when the relations between the two superpowers, the United States and the Soviet Union, experienced relaxed tension. Its main achievements were political, various summits were held and agreements were signed; in the field of economics, with increased trade; and in the field of science with increased cooperation between scientists of the two sides.
The first SALT was signed in May 1972. It had its roots within the Nuclear Test Ban Treaty of 1963 and the Non-Proliferation Treaty of 1968. SALT1 reached an agreement in three areas: the use of anti-ballistic missile systems (ABM), offensive nuclear weapons and the code of conduct. The advantage of the ABM treaty was that it provided knowledge that the other side could strike back if attacked, and hence the risk of war was diminished. However the Interim Treaty on offensive nuclear missiles was much barer.
Both sides only agreed to one temporary agreement which would expire in 1977. Moreover each country was allowed to replace old obsolete missiles with new more better performing ones, favouring the USA which was technologically more developed. Furthermore, although the number of weapons each country retained was limited there were still enough to destroy the other several times over. The Basic Principles Agreements not only laid down important rules for the conduct of nuclear warfare but also encouraged trade between the two sides. This agreement marked a shift from the atmosphere of confrontation, even thought it was a mere statement of intent. The first SALT was an achievement in the area of politics, as the treaty was signed and Nixon visited Moscow in 1972 and 1974, and Brezhnev visited Washington in 1973; and the area of economics, as relationships improved which lead to increased trade.
The Helsinki agreement started in 1973 and ended in 1975. It was a meeting between 33 states, NATO and Warsaw pact countries. Here, three sets of agreements were reached: the borders of European countries were 'inviolable', trade and technology exchanges, and soviet concession to respect human rights. The importance of the Helsinki agreement lay in the recognition of soviet control over Eastern Europe. While it's weak point was that soviet concessions gained, concerning human rights, were shown to be hollow and not respected as the human rights monitors concluded. Nevertheless, this agreement bound the soviets by their signature, and hence in future human rights crises (similar to the Hungarian uprising), the USA could legally intervene. The Helsinki agreement was an achievement for all three areas, economic as trade increased between east and west Europe, and USA and USSR; in the area of science as the cooling of relations lead to increased cooperation and technological exchange, and most importantly politic, with the recognition of the USSR's sphere of influence in Eastern Europe.
SALT2 was outlined during the Vladivostok summit in 1974. It set the same limits for missile launchers and strategic bombs, however it 'left out' cruise missiles in which the USA had a significant lead. Nevertheless many US right-wing senators saw arms control as a mechanism for allowing the USSR to catch up with us superior technology. Hence an agreement was delayed until June 1979 when SALT2 was signed, however when conflicts aroused in Iran, Angola and Afghanistan in 1980 the senate rejected it. The treaty was apparently hard to understand, ambiguous, and short lived, hence I don't see it as an achievement of dÃÂ©tente, except for the fact that it created various meetings, hence communication, between the US and the USSR. This communication was important because it looks good in the public eye, and hence leads to increased trade and cooperation between the masses of the two sides.
In conclusion, there were three main achievements of dÃÂ©tente, the two SALTs, and the Helsinki agreement which affected the two sides, economically, politically and scientifically.