Dannenberg was born in Weißenfels, Saxony-Anhalt. At the age of two, he and his family moved to Hanover, where he spent his youth. He became interested in space technology while attending a lecture by Max Valier. He witnessed two tests with a rocket driven railroad car in Burgwedel near Hanover and then joined Albert Püllenberg's group of amateur rocketeers. Dannenberg studied mechanical engineering at the University of Hanover with emphasis in diesel fuel injection, which is similar to the injection of propellants into a high pressure rocket engine. In World War II, he was drafted into the German army in 1939 and took part in the Battle of France.

   In Spring 1940, through the influence of Püllenberg, Dannenberg was discharged from the army and became a civilian employee at the German Army's Research and Development Center in Peenemünde. Under Walter Thiel's guidance he became a rocket propulsion specialist. His main assignment was the development of the 25.4 tons thrust engine for V-2 rocket production. Many improvements on which he worked could not be completed in time for production. After Thiel's death in the bombing raid of August 1943, a design freeze stopped all development efforts. He then became Walter Riedel's deputy and headed the crash effort to finalize production drawings of the V-2.

   After the end of World War II, Dannenberg was brought to the United States with 117 other German specialists under Operation Paperclip to Fort Bliss, Texas. Most members of the group performed calculations and designs of future advanced launch vehicles with longer ranges and greater payloads. About 30 members trained the U.S. Army and the support contractor General Electric to launch V-2's at the White Sands Proving Ground. Due to range limitations, all test launches had to be launched vertically to limit range.

   When the Korean War started, the group was required to leave their quarters in an Annex to the Wm. Beaumont Hospital, and was eventually transferred to the Redstone Arsenal near Huntsville, Alabama. There the development of the Redstone Missile was their first assignment.

   In 1960, Dannenberg joined NASA's newly established Marshall Space Flight Center as Deputy Manager of the Saturn program. He received the NASA Exceptional Service Medal for successfully starting the development of the largest rocket ever built, the Saturn V, which took the first human beings to the moon.

   When Arthur Rudolph came back from the army's development of the Pershing missile system, Braun assigned the management of the Saturn system to him. Dannenberg then started to work on Saturn-based space stations, which were eventually was replaced by the Space Shuttle-based ISS.

   Dannenberg retired from the Marshall Space Flight Center in 1973 and became an Associate Professor of Aerospace Engineering at the University of Tennessee Space Institute (UTSI) in Tullahoma, Tennessee. In the later years of his life he helped to found the Space Camp programs, stayed involved with them over the years and became a powerful ambassador for space exploration. Former U.S. Space & Rocket Center Director Ed Buckbee has estimated Dannenberg has had a positive effect on more than 250,000 young people. 

   Dannenberg stayed very active in his later years. As seen in the banner on the front page of V2ROCKET.COM, he wanted to keep the "information going" - as he put it. He was gracious in his communications about historical details and wanted knowledge of every new piece of information discovered concerning the V-2 and its deployment during the war.

   Born in Niederrimbach, Germany in 1913, Stuhlinger  started work at the German Atomic Energy Program in 1939 before joining the legendary Dr. Wernher von Braun's team at the German village of Peenemuende in 1943 where he worked on guidance systems for wartime rockets.

   Stuhlinger's skills were recognised and he, along with von Braun and others attached to the team, were transferred to the U.S. at the end of hostilities as part of Operation Paperclip to begin work on the U.S. space program. He became a U.S. citizen in 1955, by which time he was working on developing designs for solar-powered spacecraft at the Redstone Arsenal facility.

   Stuhlinger became director of NASA's Marshall Space Flight Centre in Huntsville, Alabama, from 1960 to 1968, and then its associate director for science from 1968 to 1975. Following his retirement in 1975, he became an adjunct professor and senior research scientist at the University of Alabama in Huntsville.

   "Let me say first, he was a gentleman. A gentleman of gentlemen, he was the most kind and most understanding most gracious of gentleman you could ever hope to meet." said fellow scientist Chuck Lundquist. "He was always the scientist, never letting people forget, yes we are putting people in space, but we also need to have that scientific reach and bring in the academic community," said Ed Buckbee, who worked for Dr. Von Braun in the 1960s. "Which he did a wonderful job of, and he was truly the chief scientist of the Von Braun team, and there was never any doubt of that."

   He is survived by his wife Irmgard, his two sons, a daughter, two grandsons and a sister.
 

   Dr. Dieter Hölsken, born in 1953, studied history, political science and journalism at the University of Münster/Westphalia. In 1982 he obtained his doctorate. The subjest of his dissertation was the history of the V-weapons.

   After some revision, that work, Die V-Waffen, was published by the Institut für Zeitgeschichte in Munich in 1984. It was later amended and published in English by Monogram in 1994 with the title; V-Missiles of the Third Reich; The V-1 and V-2.

   Sometimes called "The V-2 Bible" by V-2 researchers and historians, Hölsken's V-Missiles of the Third Reich was, for many, their first real insight into the enormity and complexity of the German WWII missile development program. It was the first work to be published post-war containing never-before-seen photographs. The research work pioneered by Hölsken has lead to other achival discoveries in recent years by like researchers.