Operation Niagara II is Launched
On 21 January PAVN opened a continuous artillery barrage directed at Khe Sanh.
It was also the launch day for Operation Niagara II. The Marine Direct Air Support Center (DASC), located at the Combat Base, was responsible for the coordination of air strikes with artillery fire. An airborne battlefield command and control center (ABCCC), in the form of a C-130 Hercules, directed strike aircraft to targets called in by ground troops and marked by forward air control (FAC) aircraft. When weather conditions prevented FAC-directed strikes, the strike bombers were directed to their targets by either a Marine TPQ-10 radar installation located at the combat base or by Air Force Combat Skyspot MSQ-77 radar stations. This LORAN-based system could direct aircraft to their targets in inclement weather and in absolute darkness.
Thus began what many considered the most concentrated application of aerial firepower in the history of warfare. On an average day 350 tactical fighter- bombers, 60 B-52 Stratofortress]]s, and 30 observation aircraft operated near the base. Westmoreland ordered Operation Igloo White to assist in the defense of Khe Sanh even though the system was only then undergoing its test and evaluation phase in Laos. On 20 January the first sensor drops took place by Observation Squadron Sixty-Seven ( VO-67 ) and by the end of the month 316 acoustic and seismic sensors had been dropped in 44 strings. The Marines credited 40 percent of intelligence available to their fire support coordination center at the base to the sensors.
Khe Sanh Combat Base.
B-52 strikes supporting the Marines were originally restricted by the Marine commander, Colonel David Lowndes, to bombing no closer than two miles from his front lines. The North Vietnamese utilized this gap to move forward and "grab the enemy by the belt" and avoid the bombing. Momyer demonstrated the effectiveness of the Stratofortress as a tactical platform by bringing the B-52 strikes safely to within three-quarters of a mile of the base and the restriction was lifted. One PAVN prisoner reported that three-quarters of his entire regiment was lost to one B-52 raid alone.
Even though Westmoreland was concentrating an unprecedented amount of firepower against PAVN forces in the vicinity of Khe Sanh, he feared that it might not be enough. For the first time, the American commander seriously considered the use of a tactical nuclear weapon. In 1976, he revealed that "Although I established a small secret group to study the subject, Washington so feared that some word of it might manage to reach the press that I was told to desist."
During January, PAVN and the Marines contested the outlying hills for control of the high ground and carried out daily artillery and mortar duels. On 7 February, however, North Vietnamese infantry, backed by Soviet-built PT-76 tanks, overran the Special Forces border camp at Lang Vei, only seven miles from the Combat Base. This was the first instance of the use of armor by PAVN during the conflict. Although the North Vietnamese continued to probe the American's defenses, the attack on Lang Vei was the last major effort by PAVN.
General William C. Westmoreland, commander of U.S. forces in Vietnam, chose the code name Operation NIAGARA for the coordination of available firepower at Khe Sanh. According to Westmoreland, the name NIAGARA invoked an appropriate image of cascading shells and bombs.3 NIAGARA would be composed of two elements. NIAGARA I was an comprehensive intelligence-gathering effort to pinpoint the available targets, while NIAGARA II was the coordinated shelling and bombing of these targets with all available air and artillery assets.