While the standards are not enforceable at the federal level, some states have chosen to enforce the SMCL standards for public water supplies in their state. MANPAD systems first developed in the 1960s and proved themselves in battle during the 1970s. MANPADS normally have ranges on the order of 3 km (1.9 mi) and are effective against attack helicopters and aircraft making ground attacks. By the 1990s, even these roles were being encroached on by new MANPADS and similar short-range weapons, like the RIM-116 Rolling Airframe Missile. This leads to three “natural” classes of SAM systems; heavy long-range systems that are fixed or semi-mobile, medium-range vehicle-mounted systems that can fire on the move, and short-range man-portable air-defense systems (MANPADS). During the war, The Soviet Union supplied 7,658 SAMs to North Vietnam, and their defense forces conducted about 5,800 launches, usually in multiples of three. Their first missions appeared to demonstrate the exact opposite, with the loss of three B-52s and several others damaged in a single mission. By the time of Operation Linebacker II in 1972, the Americans had gained critical information about the performance and operations of the S-75 (via Arab S-75 systems captured by Israel), and used these missions as a way to demonstrate the capability of strategic bombers to operate in a SAM saturated environment.

The way to avoid this was to fly lower, below the line-of-sight of missile’s radar systems. As aircraft moved ever lower, and missile performance continued to improve, eventually it became possible to build an effective man-portable anti-aircraft missile. Joseph Stalin was worried that Moscow would be subjected to American and British air raids, like those against Berlin, and, in 1951, he demanded that a missile system to counter a 900 bomber raid be built as quickly as possible. The early British developments with Stooge and Brakemine were successful, but further development was curtailed in the post-war era. The performance gap between this weapon and jet fighters of the post-war era was so great that such designs would not be effective. Known as MANPADS, the first example was a Royal Navy system known as the Holman Projector, used as a last-ditch weapon on smaller ships. The Germans also produced a similar short-range weapon known as Fliegerfaust, but it entered operation only on a very limited scale.

Coming to the same conclusions as the Germans regarding flak, the U.S. Concerns about Ajax’s ability to deal with formations of aircraft led to greatly updated version of the same basic design entering service in 1958 as the Nike Hercules, the first nuclear-armed SAM. A third design followed the American Bumblebee efforts in terms of role and timeline, and entered service in 1961 as the Sea Slug. But vehicle engineers test engines for tens of thousands of hours, often under conditions worse than a road-going car would ever encounter, and design their products accordingly. The S-25 was a static system, but efforts were also put into a smaller design that would be much more mobile. Medium-range designs, like the Rapier and 2K12 Kub, are specifically designed to be highly mobile with very fast, or zero, setup times. Modern long-range weapons include the MIM-104 Patriot and S-300 systems, which have effective ranges on the order of 150 km (93 mi) and offer relatively good mobility and short unlimbering times. These are perilous times we live in.

Yet both the Express and the Extreme are rather tiny by traditional router standards. Many of these are adapted from earlier mobile designs, but the special needs of the naval role has resulted in the continued existence of many custom missiles. Rapid improvement in the 1980s led to second generation designs, like the FIM-92 Stinger, 9K34 Strela-3 (SA-14), Igla-1 and Starstreak, with dramatically improved performance. The RSD 58 used beam riding guidance, which has limited performance against high-speed aircraft, as the missile is unable to “lead” the target to a collision point. Much of this performance increase is due to improved rocket fuels and ever-smaller electronics in the guidance systems. Consequently, SAMs evolved rapidly in the 1960s. As their targets were now being forced to fly lower due to the presence of the larger missiles, engagements would necessarily be at short ranges, and occur quickly. Originally scheduled for 5 May 2006, the IPO was postponed to 11 May 2006. The company said the delay was due to rises in fuel costs and other market pressures limiting investor demand. Because microbial fuel cells are well suited to disposing of this waste, they have generated a lot of interest lately among researchers.