V-1 and V-2 Intelligence

V-1 and V-2 Intelligence
Part of World War II technology & warfare
Location European Theatre of World War II External media: map of V-weapon sites Result ~25% fewer V-1s struck the London Civil Defence Region due to Double Cross[1]^:423
Belligerents
United Kingdom  United States Key Figures: UK: Reginald Victor Jones USA: Allen Dulles	Nazi Germany V-1: Max Wachtel V-2: Walter Dornberger
Strength
PR Squadrons (5 UK, 5 USA, & 4 CA)[2]^:113 agents & informants	V-1: 16 batteries of 220 men[3]

Military intelligence on the V-1 and V-2 weapons^[1]:437 developed by the Germans for attacks on the United Kingdom during the Second World War was important to countering them.^:437 Intelligence came from a number of sources and the Anglo-American intelligence agencies used it to assess the threat of the German V-weapons.

The activities included use of the Double Cross System for counter-intelligence and the British (code named) "Big Ben" project to reconstruct and evaluate German missile technology^[4]:74 for which Denmark, Poland, Sweden, and the USSR provided assistance. German counter-intelligence ruses were used to mislead the Allies about V-1 launch sites and the Peenemünde Army Research Center which were targeted for attacks by the Allies.

Timeline

PR — aerial photographic reconnaissance
- exchange of early stray V2 rocket.
— events regarding Nazi Germany V-weapon planning
— locations in Occupied France (German: Nordfrankreich)
— Polish reports of the Armia Krajowa
, — events regarding Anglo-American intelligence
, , — military operations (RAF, US, Luftwaffe)^[5][6]

Chronology

Date	Location/Topic	Event
1939-11-02	Oslo Report	German scientist Hans Ferdinand Mayer sent information and a sample of German technology to the British embassy in Oslo. He warned the British of current German technology including radar and planned German secret weapons such as rockets and winged missiles. Reception of the report was mixed with some believing it to be misdirection. Some of the information was second-hand and proved to be incorrect. "Head of the Scientific Section of M.I.6").
1942-05-15	Peenemünde: P-7	The Peenemunde research centre was photographed by a reconnaissance Spitfire. The photographs[2]^:114 showed "unusual" circular embankments (Test Stand VII but these were "dismissed".
1943-01-19	Peenemünde	The US requested photoreconnaissance of Usedom island.[7]^:61
1943-03-22		Wilhelm Ritter von Thoma, a General captured in North Africa was secretly recorded while in a British prison. In conversation with another fellow prisoner-of-war he disclosed he had seen the launch of a "huge" rocket[1]^:333 circa 1936-7.
1943-04-22	Peenemünde: P-7	de Havilland Mosquito DZ473 was carrying out bomb damage assessment on Stettin. On leaving Stettin, they left their cameras "running all down the north coast of Germany." The photograph interpreters at RAF Medmenham noticed an object of 25 ft (7.6 m)[8]^:16 —an "enormous cloud of steam" that had disappeared 4 seconds later in the subsequent image. The "object" was both the cooling steam from leaky flame deflector pipes and the flames of a V-2 motor at the end of a test[1]^:339,433 being directed horizontally by the P-7 flame trenches.
1943-05	Peenemünde	The senior US intelligence representative in Switzerland (Allen Dulles) identified Peenemünde to the US.[9]^:143 In 1943, agent "George Wood" began providing Dulles with intelligence.
1943-05-17	Watten	After an agent had reported "enormous trenches" at Watten during April, photoreconnaissance showed the Nord-Pas-de-Calais site was "a large rail-, and canal-served clearing in the woods, possibly a gravel pit." The Watten blockhouse which was being constructed for launching V-2s was bombed for the first time on August 27 as a suspected V-1 flying bomb site.
1943-05-14	Peenemünde: P-7	Two sorties photographed an "unusually high level of activity" at "the Ellipse" (the Reich Director of Manpower was visiting for a V-2 test launch).^:58
1943-06-04	Peenemünde	R.V. Jones received a Luxembourger's smuggled sketch of northwestern Usedom island via the "Famille Martin" network.. Also in June, agent Leon Henri Roth at Peenemünde reported "development of a large rocket which made a noise resembling that of 'a squadron at low altitude." Foreign forced laborers of the V-2 test center were housed at Camp Trassenheide, and two reports beginning in June from the camp (sent via Spain) identified the "rocket assembly hall", "experimental pit", and "launching tower".^:139
1943-06-12	Peenemünde: P-7	Mosquito PR sortie N/853[10]^:41 showed: "a white-ish cylinder about 35 feet long and 5 or so feet in diameter with fins" (R.V. Jones)[1]^:300c,340
1943-06-22		A disgruntled officer in a German High Command weapons department reported "winged' missiles… Thirty catapults had been constructed…fifteen were already serviceable."[1]^:338 At Peenemünde-West on December 24, 1942, the first ramp-launched V-1 traveled 3,000 yards^:25[9]^:18 and was the first flight powered by the Argus As 014 pulse jet engine.[11]
1943-06-23	Peenemünde: P-7	PR by a No. 540 Squadron RAF Mosquito PR.4 showed two V-2s[9][12]^:53 which were identified by interpreter André Kenny.[13]
1943-06-29	Peenemünde	Churchill and the Cabinet Defence Committee (Operations) reviewed V-2 intelligence: "Peenemünde is … beyond the range of our radio navigation beams and … we must bomb by moonlight, although the German night fighters will be close at hand and it is too far to send our own. Nevertheless, we must attack it on the heaviest possible scale."[14]
1943-07-26	Peenemünde	Mosquito PR prior to the Hydra attack detected new anti-aircraft guns and a row of six smoke generators.^:82
1943-08-16	Peenemünde	Two days prior to the Operation Hydra attack on the scientists quarters, workshops, and experimental facilities, a Westland Lysander picked up French agent Lèon Faye who carried "a detailed report of the top secret V-weapon rocket development at Peenemünde" to England.[15]
1943-08-22	Denmark	An air-launched test of an overfuelled V-1 from the "G.A.F. Research Center, Karlshagen" (Peenemunde), crashed on Bornholm, and Hasager Christiansen obtained photos of the automatic pilot, compressed air cylinder, main fuselage and wings before the German recovery team arrived.
1943-09	Peenemünde: P-7	PR showed P-7 bomb craters,[2]^:174e but Peenemünde personnel had fabricated post-Hydra bomb damage by creating craters in the sand, by blowing-up lightly damaged and minor buildings, and by painting "black and white lines to simulate charred beams".[10]^:198 Research and development on the V-2 continued promptly despite Operation Hydra, and the next V-2 test launch was 49 days later.
1943-09-07		An Ultra intercept identified that an agent tasked with gathering rocket intelligence had been captured (Amniarix survived the war).
1943-09-19		The Questionnaire…to establish the practicability…of the German Long-Range Rocket was distributed regarding the interpretation of V-2 intelligence:^:131 "it is not without precedent for the Germans to have succeeded while we doubted: the beams are a sufficient example." (September 25, R. V. Jones) vs. "at the end of the war, when we knew the full story we should find that the [60 ton] rocket was a mare's nest" (October 25, Lord Cherwell).^:3,159
1943-09-28	V-3 cannon	The Central Interpretation Unit issued a report on the Marquise-Mimoyecques site (1st bombed November 5 as a suspected V-2 launch bunker).
1943-09-30		133 V-weapon facilities had been photographed by the PRU[8] including V-1 flying bomb storage depots in Occupied France under construction since August.^:194 (They were not used for the modified sites.)
1943-09		After a Réseau AGIR informant reported unusual construction in Upper Normandy, Michel Hollard smuggled a report via Switzerland that identified 6 V-1 sites.[16]^:3
1943-10	Bois Carré	The Réseau AGIR reported the Bois Carré V-1 site (1.4 km east of Yvrench)[17] had "a concrete platform with centre axis pointing directly to London".[1]^:300e,360 The network reconnoitered 104[18] V-1 facilities and provided rough sketches such as one by André Comps of Bois Carré.[16]^:3 Comps copied the blueprints after Hollard had him infiltrate the site as a draughtsman.
1943-10-03	Siracourt	No. 542 Squadron RAF photographed the Siracourt bunker[16] (1st bombed January 31, 1944).[6]
1943 autumn		The PR image of a 40 ft × 7 ft (12.2 m × 2.1 m) object with "three [sic] fins" and a blunt nose (later identified as a V-2 without warhead) was code named Bodyline.^:149
1943-10-21		PR was ordered for the whole of Northern France.[9]^:36
1943-10-28	Bois Carré	PR by Plt Off R A Hosking in Mosquito LR424[8]^:18 of No. 540 Squadron RAF was the first to show "ski-shaped buildings" at the Bois Carré (Yvrench) site.[19]^:132
1943-11-03	Bois Carré	PR by Mosquito on No. 541 Squadron RAF sortie E/463[20] confirmed existence of a concrete platform with axis pointing directly towards London, as informed by an agent infiltrating the Bois Carré (Yvrench) construction site.[1]^:300e
1943-11-28	Peenemünde-West	Mosquito PR by Sqn Ldr Merrifield and F/O Whalley[8]^:18 (scheduled by Jones for a likely V-1 launch time), photographed a "midget aircraft" on the ramp at the edge of the Peenemünde-West airfield, which Babington-Smith detected on December 1. An additional ramp was between Zinnowitz and Zempin, and the small aircraft was code named 'Peenemünde 20'.[12]^:44
1943-11		72 "ski sites" had been photographed.[21]^:184
1943-12-04		PR was again conducted across Northern France[16]^:3 just before the December 5 start of "Crossbow Operations Against Ski Sites", which the Combined Chiefs of Staff authorized on December 2.[5] The Ninth Air Force conducted the first attack (3 sites at Ligescourt), and the 1st major strike on ski sites by VIII Bomber Command was December 24.
1943-12-04		'Druides' agent Amniarix (Jeannie Rousseau) reported the V-1 organization was moving and being renamed from Flak Regiment 155W to Flak Gruppe Creil.
1944-01-04	The Pentagon Eglin Field	Brigadier Napier of the Ministry of Supply briefed the US military regarding German long range weapon intelligence, and General Ismay directed reports be shared with the US. The US "Crossbow Committee" under General Stephen Henry of the New Developments Division[22]^:29 first met on January 6 after forming on December 29. In February and March, the US used technical intelligence data to build full-size replicas of ski site buildings to plan bombing tactics.[22]^:29
1944-02	Peenemunde: P-7	PR showed roads north of the ellipse that matched roadways later discovered after the Normandy Invasion at the Château de Molay V-2 site.
1944-02-25		The 1st transportable V-1 catapult ramp was ready (95 were ready by the end of March).^:194 Ramp sections built by the HWK in Kiel were hidden from PR until enough V-1s were ready for an initial assault. An October 22/23, 1943, area bombing had wrecked Kassel homes of Fieseler workers, delaying their transfer to the new V-1 plant at Rothwesten and as a result, delaying "the final trials of the [V-1] weapon's power unit, control-gear, diving mechanism, compass and air-log" until February and production for "three or four" months.[23]
1944-03		A plan for underground concealment of a total of 5000 V-1s to supply 8 depots (each holding 250 more for the modified launchers) was initiated for[24] Nucourt's limestone caves, Rilly-la-Montagne's rail tunnel, and Saint-Leu-d'Esserent's mushroom caves.[1]^:426 Also in March, the Brécourt V-2 bunker was ordered to be converted to a V-1 bunker.
1944-03	Poland	Intelligence headquarters received a Polish report of "an object which, though covered by a tarpaulin, bore every resemblance to a monstrous torpedo" on a Blizna railroad car that was heavily guarded by SS troops.[4]^:42 The first V-2 training launch at Blizna had been on November 5, 1943, after Major Weber's experimental staff at Köslin and Experimental Battery 444 transferred to Blizna at the end of October.[25] In May, the 953 (Semi-Mobile) Artillery Detachment started Abteilungen (English: firing detachment) training at Blizna for operations at Wizernes, and Ultra decoded Enigma messages about the transfer to Blizna.
1944-04-22		The Crossbow Committee issued a revised ski site diagram based on a January 20 sketch. By the end of March, Anglo-American attacks had destroyed nine ski sites and seriously damaged 35 more.[22]^:31 On April 19 at the request of the War Cabinet, General Eisenhower had designated Crossbow targets as the highest priority for the Combined Bomber Offensive.
1944-04-26	"Belhamelin, near Cherbourg"	PR identified the 1st camouflaged "modified" site,[16]^:8 and 12 more were identified within days.[26] The V-1 launch site design had been modified for simplicity and to use transportable catapult sections, making them "more difficult to discover and easy to replace", bombing more difficult, and completion time relatively short when V-1 supplies were sufficient. Crossbow continued bombing the obsolete and heavily damaged "ski sites" due to a German ruse to portray they were being repaired.[22]^:3 Additionally, espionage became more difficult as only German & prisoner/forced labor was used for "modified" sites instead of the previously-used French construction firms.[22]
1944-04	Mittelwerk	An intelligence report identified "Sixty flat cars left the plant; three cars had two rockets each in them." Reports came from 2 Polish laborers of the Mittelbau-Dora camp.[7]^:52
1944-05-05	Poland	PR of "the flying bomb compound" at Blizna contained an image of a rocket that R. V. Jones subsequently recognized on July 17.
1944-06-06		61 modified sites had been photographed, and 83 of 96 ski sites had been destroyed (only 2 of the ski sites launched V-1s).[22]^:32,75
1944-06-10	Belgium	A Belgian agent reported 33 railcars (carrying 99 V-1s) had passed through Ghent.
1944-06-11	Vignacourt	PR showed the Vignacourt modified site was being completed, which allowed image interpreters to predict sites would be ready to launch V-1s[2]^:174d within 3 days[21]
1944-06-11	Saleux	66 modified sites had been photographed. On the 13th just after midnight, the Saleux site launched the first combat V-1 (Hans Kammler visited the Saleux V-1 site on August 10).[2]^:258d
1944-06	RAF Medmenham	A special Medmenham image interpretation section for site photographs was set up for Duncan Sandys.
1944-06-13		Stray test V2 rocket explodes over Bäckebo Sweden, fired from Peenemünde and aimed at Baltic sea outside island of Bornholm, but overshoots the target area and lands in south Sweden. Remains are shipped to the UK .
1944-06-17	Poland	An intel report identified apparatus 17053 was sent to Peenemünde from Blizna—launches of Mittelwerk V-2s 17001-17100 (January–April) were at both Peenemünde and Blizna.
1944-06-30		Anglo-American Intelligence had identified Nucourt and Saint-Leu-d'Esserent were underground V-1 storage.[9] On June 15, 55 sites were launching V-1s, and in July, 38 sites launched 316 V-1s over a 24-hour period (25 crashed at launch).[12]^:81 By July 10, Arthur Tedder had assigned 30 Crossbow targets to Arthur Harris' RAF Bomber Command, 6 to AEAF tactical airforce, and 68 to Carl Spaatz' USSTAF.[27] Code named NOBALL, the targets numbered as high as 147 (i.e., "no ball V1 site No.147, Ligercourt [sic]").[28]
1944-07-16		A report misidentified the likely rocket fuel was hydrogen peroxide (T-Stoff), and attacks were conducted on suspected sources.
1944-07-18		Adolf Hitler ruled the V-2 launch bunker plans could be abandoned. To reduce the risk of espionage and counterattacks, mobile firing batteries were subsequently used for launching and then leaving the site.[29] An alternate concealment plan for firing V-2s just outside railway tunnels (code named Regenwurm) was also abandoned,[29] as was an earlier plan that had constructed fixed concrete launch pads in clearings of Northern France.
1944-07	Wright Field	Experts fired a V-1 engine reconstructed from "Robot Blitz" wreckage[2]^:174b (an entire V-1 was reconstructed at Republic Aviation by September 8).[30]
1944-07-21		The British inaccurately interpreted the July 18–21 effort of 50 air-launched V-1s had been "ground-launched" from the Low Countries, particularly near Ostend.
1944-07-22		Experts at Farnborough issued a report on June 13 V-2 wreckage from Sweden for which the UK agreed to exchange Spitfires.[9]^:103 The lack of lubricant in the wreckage's turbopump indicated cooling by a pumped liquefied gas, and intelligence reports about liquid oxygen as rocket fuel allowed the accurate interpretation that the payload was 2 tons or less. Conversely, the British mistakenly prepared radio jammers since the wreckage happened to have Wasserfall guidance control for a test (only a small portion of combat V-2s used radio motor cutoff—during ascent and with a 10 km interference range from the "firing point"). The test was for determining "the influence of the rocket jet on the guidance radio signal."[29]^:100
1944-07-28	Big Ben	Eight V-2 parts from Poland along with photographs, drawings, and Special Report 1/R no. 242 arrived in the UK from Brindisi, Italy. In Operation Most III an RAF Dakota had landed at an abandoned German airfield in Poland on July 25/26 and collected the 100 lb (45 kg) of cargo from the Polish underground.[2]^:158,173 The Polish parts came from V-2s launched from Blizna (one had crashed near Sarnaki without exploding on May 20), and the underground had hidden wreckage in the Western Bug river.[4]^:71 Antoni Kocjan prepared the Polish parts and information, which arrived after the British had already obtained similar material from the Swedish V-2 wreckage (as did Sanders' Blizna report). Most III also transported Jerzy Chmielewski, who had cycled 200 miles through enemy territory and reported the V-2 airbursts to the British.[1]^:444
1944-07-31	Meillerwagen	A dummy rocket and an erector trailer captured at a V-2 storage site at Hautmesnil confirmed the size of the V-2.[1]^:446
1944-08-15	Double Cross System	Use of double agents to deceive the Luftwaffe into mis-aiming the V-1s continued despite risking civilians in one area over others. After the last V-1 launch in France on September 1, Canadian troops captured the last of the initial V-1 launch sites.[24] Despite intelligence and countermeasures, V-1s killed/seriously injured over 6,000/17,000 UK civilians, even when only ~1/4 of the V-1s launched at England struck successfully.[22]^:42 Over 8000 V-1s were launched at London[31] (2,448 at Antwerp)[12]^:82—2340 reached the London Civil Defence Region from France,[32] and by June 27 in the UK, "over 200,000 houses had been damaged or destroyed by the V-1… and shattered sewage systems threatened serious epidemics."[33]
1944-08-25		Plans for aerial reconnaissance of V-2 sites were included[34]^:37 in the joint "Plan for Attack on the German Rocket Organization When Rocket Attacks Commence".[35] Based on rocket fuel intelligence the plan also identified primary and secondary liquid-oxygen plants as the third priority targets Mission 572 on August 24 had targeted rocket fuel production in France and Belgium.[6]
1944-08-25	Belgium	Based on the intelligence of V-2 liquid oxygen, the Eighth Air Force bombed 5 LOX plants (the next day's mission was "to hit liquid oxygen plants at La Louvière, Torte and Willebroek").[6]
1944-09-08	Sound ranging	Microphones in East Kent reported the times of the first London V-2s: 18:40:52 and 18:41:08 (at different locations, both Jones and Duncan Sandys recognized the supersonic "double-crack"). The ranging system provided the V-2 "trajectory from which the general launching area could be determined."[2]^:251 Civil defense officials refused to give any public information about the rocket ("It might have been a gas main explosion"), and despite that day's German headline—"Vergeltungswaffe-2 Gegen London im Einsatz" (English: Vengeance Weapon 2 in Action Against London)[29]^:119—the British's official SECRET statement was that "BIG BEN" had not been "CONFIRMED".[36]
1944-09-17	Netherlands	Airfields suspected as He 111 bases for V-1 air-launches were attacked[34]^:37 (airfields were bombed at Hopsten, Leeuwarden, Steenwijk, and Rheine).[5] Modified V-1s were air-launched from September 16-January 14 (865 launches).[37]^:104 On October 21, the first V-1 launches for Operation Donnerschlag (English: Thunderclap) began from Germany.[22]^:46
1944-09-22	Poland	After the Soviets captured Blizna in July and the Anglo-American Sanders Mission arrived on September 3, Colonel T.R.B Sanders issued his preliminary report.
1944-10	Mittelwerk	PR of Niedersachswerfen showed shadows of railcars consistent with those loaded with V-2s.
1944-10-25	Netherlands	An informant arrived behind Allied lines with reports of V-2 launches from Wassenaar.
1944-12	Royal Artillery	Project Firework was enacted by the 11th Survey Regiment to watch for "all data obtained regarding the origin and flight of enemy rockets" with the use of sound ranging stations and, after modification, the radar stations at Swingate, Rye, Pevensey, Poling, and Ventnor (11 Group); and Branscombe, Ringstead, and Southbourne (10 Group) along with the pair at St Lawrence and Newchurch.[12]^:56, 157 Radar allowed London Transport to be warned when the predicted impact (5 mile accuracy) was near the Thames subway tunnels.
1944-12-31	Netherlands	At the home of 14 yr old Hans van Wouw Koeleman, who observed and reported a few Dutch coast launches of V-2s, his father toasted the "favourable results the Germans had achieved that night" when a V-2 launch just prior to midnight "to wish Londoners a Happy New Year" failed and hit a German barracks.[36]^:133,177
1945-03-20	Netherlands	After PR showed V-1 sites at Ypenburg and Vlaardingen, an RAF Fighter Command squadron attacked the former, while on the 23rd the RAF Second Tactical Air Force attacked the latter.[9]^:133–6
1945-03	Operation Paperclip	A Polish laboratory technician found pieces of the Osenberg List of German scientists in a toilet at Bonn University.[4]^:104 The Ordnance Corps (United States Army) used the Osenberg List to compile the list of rocket scientists to be captured and interrogated (Wernher von Braun's name was at the top).[2]^:314
1945-04-11	Mittelwerk	After intel had said to "expect something a little unusual" at Nordhausen, the Army found the underground factory rockets, the dead Boelcke Kaserne forced laborers, and the evacuated Dora concentration camp. In June 1945, a mission led by the British engineer Roy Fedden inspected the factory. Earlier 1944 technical inspections included one by Frédéric Joliot-Curie and Duncan Sandys to Watten on September 10 and one by Colonel T.R.B. Sanders to Wizernes in November.[24] Similarly in July 1944, both Eisenhower and Churchill had visited the Brécourt bunker – the latter reportedly dropping an apple he was eating in astonishment of the massive facility.[38]

The day after Strategic Bombing Directive No. 4 ended the strategic air war in Europe, the use of radar was discontinued in the London Civil Defence Region for detecting V-2 launches. The last launches had been on March 27 (V-2) and March 29 (V-1 flying bomb).

References

Notes

1. Jones R. V. (1978)
2. Ordway, Frederick I, III; Sharpe, Mitchell R (1979). The Rocket Team (index). Apogee Books Space Series 36. New York: Thomas Y. Crowell. pp. 57,114,117,174b–e,251,258d. ISBN 1-894959-00-0.
3. "Flak Regiment 155". Axis History Forum. August 12, 1943. Retrieved 2010-03-06. External link in |work= (help) (the forum posting cites Jones)
4. McGovern, James (1964). Crossbow and Overcast. New York: W. Morrow. p. 71,74.
5. "Campaign Diary". Royal Air Force Bomber Command 60th Anniversary. UK Crown. Retrieved 2009-03-22.
   1940: May-June (Battle of France), June-October (Battle of Britain) July-December,
   1941: January-April May-August September- December
   1942: January, February, March, April, May, June, July, August, September, October, November, December
   1943: January, February, March, April, May, June, July, August, September, October, November, December
   1944: January, February March, April, May, June (D-Day), July, August, September, October, November, December
   1945 January, February, March, April
6. McKillop, Jack. "Combat Chronology of the USAAF". Retrieved 2007-05-25.
   1942: January, February, March, April, May, June, July, August, September, October, November, December
   1943: January, February, March, April, May, June, July, August, September, October, November, December
   1944: January, February, March, April, May, June, July, August, September, October, November, December
   1945: January, February, March, April, May, June, July, August, September
7. Garliński, Józef (1978). Hitler's Last Weapons: The Underground War against the V1 and V2. New York: Times Books. pp. 52, 82.
8. Bowman, Martin W. Mosquito Photo-Reconnaissance Units of World War 2 (Google Books). p. 18.
9. Collier, Basil (1976) [1964]. The Battle of the V-Weapons, 1944-1945. Yorkshire: The Emfield Press. pp. 68,82,84,103. ISBN 0-7057-0070-4.
10. Middlebrook, Martin (1982). The Peenemünde Raid: The Night of 17–18 August 1943. New York: Bobs-Merrill. pp. 39, 41, 198.
11. Pocock, Rowland F (1967). German Guided Missiles of the Second World War. New York: Arco Publishing Company, Inc. p. 22.
12. Cooksley, Peter G (1979). Flying Bomb. New York: Charles Scribner’s Sons. pp. 44,53,56,81,157.
13. "Constance Babington Smith". The Daily Telegraph (London). 2000-08-09.
14. "The V2 rocket: A romance with the future". Science in war. The Science Museum. 2004. Retrieved 2008-09-22.
15. Verity, Hugh. We Landed by Moonlight. p. 118. (cited by Middlebrook p. 39)
16. "The V-Weapons". After The Battle: 3, 14, 16. 1974.
17. "V1, V2 & V3" (in German). christianCH.ch. Retrieved 2010-02-11.
18. "Eurostar remembers Michel Hollard". 26 April 2004. Retrieved 2010-03-15.
19. Sharp, C. Martin; Bowyer, Michael J. F. (1971). Mosquito. London: Faber & Faber. p. 132. ISBN 0-85979-115-7.
20. "Operation Crossbow - V1 Bois Carré Sites". The National Collection of Aerial Photography. Royal Commission on the Ancient and Historical Monuments of Scotland. Retrieved 2011-12-26.
21. Gurney, Gene (Major, USAF) (1962). The War in the Air: a pictorial history of World War II Air Forces in combat. New York: Bonanza Books. p. 184.
22. Zaloga, Steven J. (2008) [2007]. German V-Weapon Sites 1943-45 (Google Books). Fortress Study Group (72). New York: Osprey Publishing Ltd. pp. 3, 25, 29, 31–2, 42, 46, 75. ISBN 978-1-84603-247-9.
23. D'Olier, Franklin; Alexander, Ball, Bowman, Galbraith, Likert, McNamee, Nitze, Russell, Searls, Wright (September 30, 1945). "The Secondary Campaigns". United States Strategic Bombing Survey, Summary Report (European War). Retrieved 2008-09-22. Cite uses deprecated parameter |coauthors= (help); External link in |work= (help) (cited by Mets p. 239, which has the "three or four" numbers)
24. Henshall, Phillip (1985). Hitler’s Rocket Sites. New York: St Martin's Press. pp. 64,111.
25. Dornberger, Walter (1954) [1952: V2--Der Schuss ins Weltall]. V-2. translated by James Cleugh and Geoffrey Halliday (1979 Bantam ed.). New York: Viking Press. p. 214. ISBN 0-553-12660-1.
26. "V-Bomb Photo Search". Life magazine: 143. October 28, 1957. Retrieved 2010-02-12.
27. Mets, David R. (1997) [1988]. Master of Airpower: General Carl A. Spaatz (paperback ed.). p. 239.
28. Clostermann, Pierre (2004). The Big Show. London: Weidenfeld & Nicolson. ISBN 0-297-84619-1. Retrieved 2010-03-15.
29. Huzel, Dieter K (1960). Peenemünde to Canaveral. Englewood Cliffs NJ: Prentice Hall. p. 93.
30. U.S. Air Force Tactical Missiles, (2009), George Mindling, Robert Bolton ISBN 978-0-557-00029-6
31. von Braun, Wernher (Estate of); Ordway III, Frederick I, and Dooling, David Jr (1985) [1975]. Space Travel: A History (first ed.). New York: Harper & Row. p. 105. ISBN 0-06-181898-4. Cite uses deprecated parameter |coauthors= (help)
32. Collier, Basil (1995) [1957]. Butler, J. R. M., ed. The Defence of the United Kingdom. United Kingdom Military Series. Her Majesty's Stationery Office. ISBN 1-870423-09-7. (cited as the "Official History" by Jones, p. 423)
33. Eisenhower, David (1991) [1986]. Eisenhower: At War 1943-1945. New York: Wings Books. p. 349. ISBN 0-517-06501-0. Of the 10,500 V-I's launched at England, an estimated 25 percent flew off course because of malfunction. Roughly 20 percent penetrated British defenses and hit targets, claiming 10,000 lives and 1.1 million homes
34. Gruen, Adam L. "Preemptive Defense, Allied Air Power Versus Hitler’s V-Weapons, 1943–1945". The U.S. Army Air Forces in World War II. pp. 4(Round 1),5(Round 2). Retrieved 2007-05-07.
35. Craven, Wesley Frank; Cate, James Lea (editors). (Volume 3) Europe: Argument to V-E Day (Google Books). The Army Air Forces in World War II. p. 535. Cite uses deprecated parameter |coauthors= (help)
36. Johnson, David (1982). V-1, V-2: Hitler's Vengeance on London. Stein and Day. pp. 117, 130.
37. Pocock, Rowland F (1967). German Guided Missiles of the Second World War. New York: Arco Publishing Company, Inc. p. 104.
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Bibliography

Jones, R. V. (1978). Most Secret War: British Scientific Intelligence 1939-1945. London: Hamish Hamilton. ISBN 0-241-89746-7.