Combat Skyspot was the ground-directed bombing (GDB) operation of the Vietnam War by the United States Air Force using Bomb Directing Centrals and by the United States Marine Corps using Course Directing Centrals ("MSQ-77 and TPQ-10 ground radars"). Combat Skyspot's command guidance of B-52s and tactical fighters and bombers—"chiefly flown by F-100's"—at night and poor weather was used for aerial bombing of strategic, close air support, interdiction, and other targets. Using a combination radar/computer/communications system ("Q" system) at operating location in Southeast Asia, a typical bombing mission (e.g., during Operation Arc Light with a "cell" of 3 Boeing B-52 Stratofortresses) had an air command post turn over control of the mission to the radar station, and the station provided bomb run corrections and designated when to release bombs.
Planning of Vietnam GDB missions included providing coordinates with 10 m (11 yd) accuracy to the radar sites, handoff of the bomber from air controllers (e.g., a DASC) to the site, tracking the aircraft by radiating the bomber (e.g., activating the 400 Watt Motorola SST-181 X Band Beacon Transponder), and radioing of technical data from the aircrew to the radar site such as the airspeed/heading for the central to estimate wind speed on the bomb(s). With the bomber near a designated "Initial Point" the GDB site would begin a radar track (Bomb Directing Centrals would calculate a computer track and solve the "bomb problem" for the aircraft position.)
For B-52 missions the site personnel verbally transmitted guidance commands to the aircraft crew by radio (lead aircraft for multi-ship formations) to adjust the flight path toward an eventual release point for the actual bomb(s). Site personnel verbally directed release of the ordnance from the aircraft by voice countdown. This was a manual process requiring training, practice and adherence to procedure. Both the site and aircrew were authorized to "withhold" release at any point if doubt arose. All communications were tape recorded by the aircrew for post strike debriefing.
|Part of Vietnam War|
|United States||North Vietnam|
|Commanders and leaders|
7th Air Force coordinator: Lt Col Robert C. Seitzberg:34|
1CEVG Det. 15: tbd
LS-85: Lt Col Gerald Clayton
USAF sites: 8 |
USMC sites: tbd
|Vietnam War ground-directed bombing sites|
|site||location||accuracy in ft||notes|
|Bien Hoa Air Base||238|
|Nakhon Phanom RTAFB||322||AN/MSQ-77, c. 1969 AN/TSQ-96|
|Đông Hà Combat Base,  Hue-Phu Bai, Monkey Mountain (Da Nang)||291||overrun March 31, 1972|
|Dalat, later Ubon RTAFB|
|OL-26||Binh Thuy Air Base, RVN||222|
|Nakhon Phanom RTAFB||1967 AN/TSQ-81|
|mountaintop of Phou Pha Thi||1967-8 AN/TSQ-81 (destroyed 10 March 1968)|
|Lima Site 44
|Salavan, Laos||Channel 72 emplaced April 1966|
|Long Tieng, Laos||Channel 79 emplaced May 1966|
|Lima Site 61
|Muang Phalane, Laos||Channel 77 emplaced 26 March 1967:34|
Similar to World War II GDB and Korean War GDB, Combat Skyspot was planned during 1965 development of the Reeves AN/MSQ-77 Bomb Directing Central with a new integrating ballistic computer using vacuum tubes to continually compute the bomb release point during the bomb run (the USMC AN/TPQ-10 directed aircraft to a predetermined release point). Planning for the USAF vacuum-tube trajectory computer/radar system began in early 1965 and in October 1965, F-100s tested the AN/MSQ-77 at Matagorda Island General Bombing and Gunnery Range on the Texas Gulf Coast (the Matagorda training unit was later moved to Bergstrom Air Force Base). In 1967 a helicopter-transportable variant of the AN/MSQ-77 in rigid shelters (AN/TSQ-81) was developed for Commando Club bombing of northern North Vietnam targets (Red River Delta), and in 1969 training for an additional transportable variant with tower-mounted antenna and digital computer (AN/TSQ-96) was being conducted at the Reeves Instrument Corporation in New York. "In March 1966 the first MSQ-77 arrived at Bien Hoa" Air Base ("activated" April 1 to use the "reverse MSQ method".)
Combat Skyspot was first used "to support fighting ground troops" on July 2, 1966; and the initial 15,000 Skyspot sorties from March 1966-March 1967 included the respective 35%, 46%, and 54% "of the B-52D sorties flown" from July-December 1966, in January 1967, and in March 1967. Similar to the lead bomber for 3-ship B-52 missions, a North American F-100 Super Sabres could use Skyspot to act as a pathfinder for Republic F-105 Thunderchiefs. On July 3, 1966, "24-hour all-weather bombing [was] authorized against targets in Laos [using] MSQ-77 ground director bombing system (SKY SPOT)" and on July 5, "Quick Run" began with Skyspot airstrikes where "MACV could request priority targeting resulting in B-52D missions diverted from their primary targets prior to take off or after takeoff". In addition to Arc Light B-52 airstrikes, Skyspot was used against Cambodia targets of Operation Menu from Bien Hoa Air Base and by Operation Niagara. The Combat Skyspot "Operations Order (OPORD) 439–67" was published March 10, 1967; and notable battles using Skyspot include:
Skyspot also supported Lockheed AC-130 gunships, BLU-82/B drops from MC-130 Commando Vault aircraft to clear landing zones, at least 1 helicopter evacuation of wounded on August 13, 1966, and "since many maps of South Vietnam contained distance errors of up to 300 meters", target surveying by tracking an observation aircraft flying circles around a target for plotting its coordinates. As with "loran-controlled photography" for target geolocation, Skyspot was also used for surveying during 'recce escort' missions, e.g., for Commando Club calibration with an RF-4C reconnaissance jet taking high speed target photos during a "Run for the Roses" ("almost guaranteed to produce copious SAM firings"). Interdiction occasionally used Skyspot to walk subsequent bombs onto a small target such as by Commando Nail forward air controller, e.g., to "hit a couple bull dozers … The Fac would say [you got him pause nope he's back on the dozer, move your coordinates to the adjusted location]… It took 4 F-4 strikes to knock it out." "On 22 December 1968, RF-4Cs from the 12 and 16 TRS began flying bomb damage assessment missions to evaluate" Skyspot accuracy.
Commando Club was a Combat Skyspot operation for ground-directed bombing of Red River Delta targets (Hanoi, Haiphong, etc.) out of range of the initial Combat Skyspot sites using a specialized radar emplaced by Heavy Green at one of the Laos Sites of the Vietnam War. The operation also bombed clandestine targets in the neutral Kingdom of Laos (e.g., for self-defense during the Battle of Route 602) using Detachment 1 personnel of the 1043rd Radar Evaluation Squadron performing AN/TSQ-81 operations as Lockheed civilians (volunteers discharged from the USAF for cover). Due to limited reliability of the AN/TSQ-81 radios, an intermediary aircraft (EC-121:b or "usually a C-135…decoy ship") provided a "radio relay [and] surveillance/control channel" (callsign: WAGER) between the radar and the bomber.
|Commando Club/total missions by target area & period|
|November||20/153 (13%)||1/268||21/421 (5%)|
|December||20/94 (21%)||67/327 (20%)||87/421 (21%)|
|January||29/125 (55%)||23/320 (10%)||52/445 (12%)|
|February||27/49 (55%)||142/375 (38%)||169/424 (40%)|
|March 1–10||3/6 (50%)||165**/182 (91%)||168/188 (89%)|
|Total||99*/427 (20%)||398/1472 (27%)||497/1899 (26%)|
|*The 99 Commando Club missions on NVN used ~500 sorties.|
(The last was on the Thai Nguyen RR yard.)
**Only 153 of the March 1–10 Commando Club missions were on Laos targets.:62
The LS-85 radar with callsign "Wager Control" at 396.2 MHz:a and day/night shift crews of 5 men each became operational on November 1, 1967; and trial missions by Republic F-105 Thunderchiefs were led by Col. John C. Giraudo (355th Fighter Wing commander). F-105 Commando Club missions included the November 15, 1967, 357th Tactical Fighter Squadron bombing of Yên Bái Air Base in Route Package 5 ("no BDA possible") and the defeated November 18 raid of 16 F-105s of the 388th Tactical Fighter Wing—preceded by 4 F-105 Wild Weasels—on Phúc Yên Air Base (JCS Target 6). The latter mission's loss of 2 Wild Weasels to MiGs and then some of the bombers to SAM sites that tracked the USAF jamming resulted in temporary suspension of Commando Club until electronic countermeasures were improved. Through November 16, LS-85 had effected a direct hit (zero miss distance) as well as a 5 mi (8.0 km) miss: the Commando Club CEP for "14 runs was 867 feet" while other Skyspot sites for 1967 missions averaged 300–350 ft (91–107 m) error at ranges ≤100 nmi (190 km; 120 mi). LS-85 accuracy was improved during the suspension period, another UHF radio was added at the summit, and the radio relay's secondary task of surveilling for MiGs was eliminated.
Commando Club was resumed by November 21 when F-105s attacked the Yên Bái airfield (also on December 1 & 23, January 5, & February 11.):d LS-85 directing bombings of Laos' Ban Phougnong truck park on December 22, a target "25 miles west of [LS-85's TACAN] Channel 97" on December 28, and "a target 20 miles east of San Neua" December 31; and "Commando Club under Wager Control" bombed the Kim Lo Army Barracks northwest of Hanoi on February 7, 1968,:c a Route Pack V target on February 11, and the "Phuc Yen (JCS 6) airfield" & "the Ban Nakay truck park in Northern Laos" on February 19.:d Arc Light B-52s and other aircraft also flew missions of Commando Club, which were 20% (less than 1 per day) of all bombing missions on North Vietnam targets during November 1 – March 10. Commando Club airstrikes against Laos targets included operations to interdict enemy advances on LS-85 such as the Battle of Route 602. "On 21 February the [Laos] Ambassador authorized the Local Area Defense Commander (alternately the senior CIA officer or the FAC) to use the TSQ radar to direct any and all strikes within 12 kilometers of the summit" and "between the 20th and 29th, 342 sorties hit within 30 kilometers of Phou Phathi." Commando Club operations during the Battle of Route 602 were part of the approximately 400 Commando Club missions out of the "1,472 BARREL ROLL Strike missions" flown "around" LS-85 from November 1 – March 10. Despite the bombing campaign, the enemy reached LS-85 and it was captured during the Battle of Lima Site 85 on March 10/11, 1968.
The AN/TSQ-96 at Ubon RTAFB directed the "last Arc Light strike of the Indochinese conflicts…on August 15, 1973", and the last Vietnam War Skyspot mission was also from OL-25 (in December 1975 the TSQ-81 that had been at OL-23 was moved near Osan Air Base, Korea.) The AN/MSQ-77 averaged 300–350 ft (91–107 m) error for 1967 missions at ranges ≤100 nmi (190 km; 120 mi), and the AN/TPQ-10 had a CEP of 150 ft (46 m).far?] For Route Package I sorties, the "major increase in high altitude MSQ-77 bombing was probably the most important reason for loss reduction" (fewer shoot downs), Casualties associated with Combat Skyspot included a Detachment 15 NCO killed in an enemy rocket attack, 6 of a site survey team killed in a 1966 ambush, and the 13 KIA of the Battle of Lima Site 85. In 1989, remains of an F-4C Weapon System Officer shot down during a November 10, 1967, AN/MSQ-77 bomb run were recovered in Southeast Asia, and US remains from the LS-85 battle were identified in 2005 & 2012. The Combat Skyspot Memorial on Andersen Air Force Base, Guam, identifies personnel killed in Southeast Asia (its AN/MSQ-77 antenna was destroyed by a typhoon c. 2007).
|1967 Dong Ha "SKY SPOT" entrance|
Skyspot's accuracy let heavy bombs be dropped on occasion within 250 meters of friendly positions. …many maps of South Vietnam contained distance errors of up to 300 meters. … Skyspot (S) MSQ-77 and TPQ-10 ground radars
In SEA, the MSQ-77 system is utilized by tactical fighters, tactical bombers, and B-52 bomber aircraft for controlled release of ordnance on targets during periods of darkness and adverse weather. It was used by: F-100, F-4C, F-105, A-1E, A-26, B-52, and B-57, though most frequently used by F-100s and B-52s.
Preplanned radar-directed strikes were fragged by the TACC along with other missions. After takeoff, the strike aircraft were passed from the appropriate CRC/CRP to an MSQ-77 [or] TPQ-10 radar station that directed the strike.
In SEA, the MSQ-77 system is utilized by tactic~l fighters, tactical bombers, and 8–52 bomber aircr~ft for controlled release ti or~nance'on targets during periods of darkness and adverse weather. … The F-IOO and B-S2 aircraft use the system most frequently.(p. 7)
OL-23 (call sign LID)…ran many Arc Light strikes against targets in northern Laos.
OL-26 (call sign GAP) was deeply involved with the secret bombing in Cambodia
By December 1966, 35 percent of the B-52D sorties flown were MSQ directed, increasing to 46 percent in January and 54 percent in March.
Finally, a B-52 from U Tapao carrying 108 500-pound bombs ran a test mission on 26 February, guided by Skyspot . The delivery was precise and the equipment operated well . The following day, four missions were run close to the defenders at Khe Sanh. During March, 44 close-support sorties were run ."
One night we worked with a Nail Fac and hit a couple bull dozers. …the fac gave coordinates, we would run an F4 on the spot. The Fac would say you got him pause nope he's back on the dozer, move your coordinated to whatever the new coordinates were. It took 4 f 4s to finally nock it out.
34 TFS were diverted to a target in Laos as a result of the North Vietnamese attack on Lima Site 85. They took off at 0715 and returned after 2 hours 55 minutes. … We were diverted up to Lima 85 up by the North TACAN station. The bad guys were trying to storm the hill. The hill was sticking up through the clouds but we couldn't detect any enemy action. The A-1Es were working over the enemy but they wouldn't let us in on the action. Instead they put us in on an enemy gun emplacement about 10 miles away.
We already had a 600-foot STOL strip three-quarters of the way up the mountain for resupplying local Meo guerrilla … One wounded and extraordinarily unlucky technician was killed, shot through the backduring helicopter evacuation.
From November 1967 to March 1968, controllers at Phou Pha Thi directed nearly a hundred "Commando Club" missions (about five hundred sorties) against the Red River Delta.
|url=(help). Retrieved 2012-06-06.
On 1 November 1967, another MSQ-77 became operational in Laos, but it was destroyed by the enemy in March 1968.
The 1st Combat Evaluation Group (initially "1CEG", later "1CEVG") was a Strategic Air Command (SAC) unit. It was formed on 1 August 1961 to merge the 3908th Strategic Standardization Group for SAC aircrew evaluation with the 1st Radar Bomb Scoring Group that had originated from the 263rd Army Air Force Base Unit which transferred from 15th AF to directly under Strategic Air Command c. 1946. The 1CEVG formed after SAC switched to low-level tactics to counter Soviet surface-to-air missiles ("Oil Burner" training routes in 1959) and SAC had "developed a Radar Bomb Scoring field kit for use in NIKE Systems" in early 1960 for scoring SAC training missions against US Hercules SAM sites. The 1CEVG headquarters included an Office of History and a "standardization and evaluation school" for command examiners.99th Range Group
The 99th Range Group is an inactive United States Air Force (USAF) unit. It was last stationed at Nellis AFB, Nevada, where it was responsible for the Nevada Test and Training Range (NTTR).Ashland Radar Station
Ashland Radar Station was a United States Air Force station located in Ashland, Maine operational from around 1975 to 1990. Sitting on 6.59 acres (2.67 ha).Battle of Lima Site 85
The Battle of Lima Site 85, also called Battle of Phou Pha Thi, was fought as part of a military campaign waged during the Vietnam War and Laotian Civil War by the North Vietnamese army and the Pathet Lao, against airmen of the United States Air Force's 1st Combat Evaluation Group, elements of the Royal Lao Army, Royal Thai Border Patrol Police, and the Central Intelligence Agency-led Hmong Clandestine Army. The battle was fought on Phou Pha Thi mountain in Houaphanh Province, Laos, on 10 March 1968, and derives its name from the mountaintop where it was fought or from the designation of a 700 feet (210 m) landing strip in the valley below, and was the largest single ground combat loss of United States Air Force members during the Vietnam War.
During the Vietnam War and the Laotian Civil War, Phou Pha Thi mountain was an important strategic outpost which had served both sides at various stages of the conflict. In 1966, the United States Ambassador to Laos approved a plan by the United States Air Force (USAF) to construct a TACAN site on top of Phou Pha Thi, as at the time they lacked a navigation site with sufficient range to guide U.S. bomber aircraft towards their targets in North Vietnam. In 1967 the site was upgraded with the air-transportable all-weather AN/TSQ-81 radar bombing control system. This enabled American aircraft to bomb North Vietnam and Laos at night and in all types of weather, an operation code-named Commando Club. Despite U.S. efforts to maintain the secrecy of the installation, which included the "sheep-dipping" of the airmen involved, U.S. operations at the facility did not escape the attention of the North Vietnamese and Pathet Lao forces.
Towards the end of 1967, North Vietnamese units increased the tempo of their operations around Phou Pha Thi, and by 1968 several attacks were launched against Lima Site 85. In the final assault on 10 March 1968, elements of the VPA 41st Special Forces Battalion attacked the facility, with support from the VPA 766th Regiment and one Pathet Lao battalion. The Hmong and Thai forces that were defending the facility were overwhelmed by the combined North Vietnamese and Pathet Lao forces.Ground-directed bombing
Ground-directed bombing (GDB) is a military tactic for airstrikes by ground-attack aircraft, strategic bombers, and other equipped air vehicles under command guidance from aviation ground support equipment and/or ground personnel (e.g., ground observers). Often used in poor weather and at night (75% of all Vietnam War bombings "were done with precision [sic] GDB"), the tactic was superseded by an airborne computer predicting unguided bomb impact from data provided by precision avionics (e.g., GPS, GPS/INS, etc.) Equipment for radar GDB generally included a combination ground radar/computer/communication system ("Q" system) and aircraft avionics for processing radioed commands.A 21st century variant of ground-directed bombing is the radio command guidance for armed unmanned aerial vehicles to effect ground-directed release of ordnance (e.g., precision-guided munitions for bombing such as the AGM-114 Hellfire).Hawthorne Bomb Plot
Hawthorne Bomb Plot is a Formerly Used Defense Site that had a Strategic Air Command (SAC) AUTOTRACK radar station during the Cold War. Operations began at a temporary RBS train site for RBS Express #2 was at the Hawthorne area in December 1961, and the 11th Radar Bomb Scoring Squadron subsequently established the fixed military installation for Radar Bomb Scoring in Babbitt, Nevada, the military housing community near the local Navy/Army depot.Detachment 12 operated and maintained the radars, e.g., c. 1977-2000, Reeves AN/MSQ-77 Bomb Directing Central (serial number 10) was at the Hawthorne Bomb Plot after use for Guam RBS and Vietnam Combat Skyspot bombing. The unit was reassigned to 1CEVG's RBS Division in 1966 and tracked training sorties at the Nellis Air Force Range (e.g., during the Vietnam War) and scored SAC bombers. Hawthorne's Oil Burner route ("OB-10 Hawthorne") for SAC low-level bomber flights extended from a "point west of Elko, Nevada, running southwest to Nuna, Nevada" at flight level "FL130-140" (the Tonopah "SAC Targets 1 and 2" were at South Antelope Lake.)The USAF detachment publicized their 1985 move to the Havre Radar Bomb Scoring Site, but the Hawthorne radar station was still used by NAS Fallon in 1993, and the Whiskey Flats RV park was established in the general location of the former radar station in 2004.Interior Radar Bomb Scoring Site
The Interior Radar Bomb Scoring Site (callsign Badlands Bomb Plot) opened in August 1960 on Hurley Butte (43.719846°N 102.14294°W / 43.719846; -102.14294), adjacent to the Pine Ridge Indian Reservation and a few miles from Interior, South Dakota. The Interior RBSS is a Formerly Used Defense Site, that closed in 1968.Lima Site 85
Lima Site 85 (LS-85 alphanumeric code of the phonetic 1st letter used to conceal this covert operation) was a clandestine, military installation in the Royal Kingdom of Laos guarded by the Hmong "Secret Army", the Central Intelligence Agency, and the United States Air Force used for Vietnam War covert operations against communist targets in ostensibly neutral Laos under attack by the Vietnam People's Army. Initially created for a CIA command post to support a local stronghold, the site was expanded with a 1966 TACAN area excavated on the mountaintop where a 1967 command guidance radar was added for Commando Club bombing of northern areas of North Vietnam. The site ended operations with the Battle of Lima Site 85 when most of the U.S. technicians on the mountaintop were killed, including CMSgt Richard Etchberger. For his heroism and sacrifice, Etchberger received the Air Force Cross posthumously. The operation remained classified, however, and the existence of the award was not publicly acknowledged until 1998. After the declassification of LS 85 and a reevaluation of his actions, Etchberger was awarded the Medal of Honor in 2010.Matagorda Island Air Force Base
Matagorda Island Air Force Base ( (listen)) is a closed military airfield on the north end of Matagorda Island, northeast of Corpus Christi, Texas. It was closed by the United States Air Force in 1975.Nevada Test and Training Range
The Nevada Test and Training Range (NTTR) is one of two military training areas used by the United States Air Force Warfare Center at Nellis Air Force Base in Nevada. The NTTR land area includes a "simulated Integrated Air Defense System", several individual ranges with 1200 targets, and 4 remote communication sites. The current NTTR area and the range's former areas have been used for aerial gunnery and bombing, for nuclear tests, as a proving ground and flight test area, for aircraft control and warning, and for Blue Flag, Green Flag, and Red Flag exercises.No. 1 Operational Conversion Unit RAAF
No. 1 Operational Conversion Unit (No. 1 OCU) was an operational training unit of the Royal Australian Air Force (RAAF). Formed in January 1959 at RAAF Base Amberley, Queensland, its role was to convert pilots and navigators to the English Electric Canberra bombers flown by Nos. 1, 2 and 6 Squadrons. The unit's complement of Canberras included T.4 and Mk.21 dual-control trainers, and Mk.20 bombers. Originally a component of No. 82 Wing, No. 1 OCU became an independent unit at Amberley in April 1968, its focus being the provision of operationally ready pilots for service with No. 2 Squadron in the Vietnam War. No. 1 OCU was disbanded in June 1971, following the withdrawal of No. 2 Squadron from South-East Asia. By then the RAAF's only Canberra unit, No. 2 Squadron ran its own conversion courses before disbanding in 1982.Operation Arc Light
During Operation Arc Light (Arc Light, and sometimes Arclight) from 1965 to 1973, the United States deployed B-52F Stratofortresses from bases in the US to Guam to provide close air support to ground combat operations in Vietnam. The conventional bombing campaign was supported by ground-control-radar detachments of the 1st Combat Evaluation Group (1CEVG) in Operation Combat Skyspot. Arc Light operations usually targeted enemy base camps, troops concentrations, and supply lines.Operation Commando Hunt
Operation Commando Hunt was a covert U.S. Seventh Air Force and U.S. Navy Task Force 77 aerial interdiction campaign that took place during the Vietnam War. The operation began on 11 November 1968 and ended on 29 March 1972. The objective of the campaign was to prevent the transit of People's Army of Vietnam (PAVN) personnel and supplies on the logistical corridor known as the Ho Chi Minh Trail (the Truong Son Road to the North Vietnamese) that ran from the southwestern Democratic Republic of Vietnam (North Vietnam) through the southeastern portion of the Kingdom of Laos and into the Republic of Vietnam (South Vietnam).Operation Niagara
Operation Niagara was a U.S. Seventh Air Force close air support campaign carried out from January through March 1968, during the Vietnam War. Its purpose was to serve as an aerial umbrella for the defense of the U.S. Marine Corps Khe Sanh Combat Base on the Khe Sanh Plateau, in western Quang Tri Province of the Republic of Vietnam. The base was under siege by an estimated three-divisional force of the People's Army of Vietnam (PAVN).Phúc Yên Air Base
Phúc Yên Air Base (also known as Noi Bai Air Base) is a Vietnam People's Air Force (VPAF) (Không quân Nhân dân Việt Nam) military airfield located immediately north of Noi Bai International Airport and approximately 30 km (19 mi) north of Hanoi.Radar Bomb Scoring
Radar Bomb Scoring is a combat aviation ground support operation used to evaluate Cold War aircrews' effectiveness with simulated unguided bomb drops near radar stations of the United States Navy, the USAF Strategic Air Command, and Army Project Nike units. USAF RBS used various ground radar, computers, and other electronic equipment such as jammers to disrupt operations of the bomber's radar navigator, AAA/SAM simulators to require countermeasures from the bomber, and Radar Bomb Scoring Centrals for estimating accuracy of simulated bombings. Scores for accuracy and electronic warfare effectiveness were transmitted from radar sites such as those at Strategic Range Training Complexes (e.g., from Detachment 1 at the "La Junta Bomb Plot").
Most of the SAC sites were in the continental US with units (detachments) manned by technicians and operators of the Automatic Tracking Radar Specialist career field (AutoTrack). Radar Bomb Scoring and the Autotrack specialty were discontinued shortly after the end of the Cold War when increased munitions accuracy (e.g., GPS-guided JDAMs 1st used in 1993) reduced the need for scoring of simulated bomb runs, and GPS avionics allow onboard tracking for "no-drop bomb scoring" of unguided bombs.Reeves AN/MSQ-35 Bomb Scoring Central
The Reeves AN/MSQ-35 Bomb Scoring Central was a United States Air Force dual radar system with computerized plotting board for evaluating accuracy of Strategic Air Command bomber crews by the 1st Combat Evaluation Group.Reeves AN/MSQ-77 Bomb Directing Central
The Reeves AN/MSQ-77 Bomb Directing Central, Radar (nickname "Miscue 77") was a USAF automatic tracking radar/computer system for command guidance of military aircraft during Vietnam War bomb runs at nighttime and during bad weather. Developed from the Reeves AN/MSQ-35, the AN/MSQ-77 reversed the process of Radar Bomb Scoring by continually estimating the bomb impact point before bomb release with a vacuum tube ballistic computer. Unlike "Course Directing Centrals" which guided aircraft to a predetermined release point, the AN/MSQ-77 algorithm continuously predicted bomb impact points during the radar track while the AN/MSQ-77's control commands adjusted the aircraft course. A close air support regulation prohibited AN/MSQ-77 Combat Skyspot bombing within 1,000 yd (910 m) of friendly forces unless authorized by a Forward Air Controller, and "on several occasions" strikes were as close as 273 yd (250 m).Post-war the MSQ-77 was used on US and other training ranges for Radar Bomb Scoring (RBS). The AN/MSQ-77 was also periodically used for post-Vietnam commanding of bombers during simulated ground directed bombing to maintain aircrew and radar crew GDB proficiency (RBS could be used to score the simulated GDB mission). Most AN/MSQ-77s ware replaced by solid-state equipment near the end of the Cold War.Đông Hà Combat Base
Đông Hà Combat Base (also known as Camp Spillman or simply Đông Hà) is a former U.S. Marine Corps and U.S. Army base northwest of Quảng Trị in central Vietnam. The base was first used by the 4th Marines in late April 1966. In mid-July Đông Hà was used by the Marines as a helicopter base and logistics area. Numerous US marine and army units rotated through the base, and several artillery units were based there.
During 1968 units of the People's Army of Vietnam (PAVN) made repeated attacks on the base, on one occasion destroying its ammunition dump. During these attacks, and in other actions in the general area the PAVN suffered heavy casualties. By January 1972 the Army of the Republic of Vietnam (ARVN) 3rd Division had assumed responsibility for the defense of Đông Hà and the area north of Highway 9. During April 1972 the PAVN made repeated assaults on Dong Ha and it fell on the 28th.