Thirty Years of Sounding Rockets - Reflections Following a Reunion at ESRANGE

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1 Thirty Years of Sounding Rockets - Reflections Following a Reunion at ESRANGE A. Pedersen, P. Colson, R. Meiner*, A. Menardi & T. R. Sanderson ESA/ESTEC, Noordwijk, The Netherlands * Retired P. Englund ESRANGE, Kiruna, Sweden Even as the first launch of ESRO's Sounding Rocket Programme departed from the Salto de Quirra military range in Sardinia in June 1964, planning was already completed for ESRO's own range in Kiruna, Sweden to probe the auroral ionosphere and atmosphere. ESRANGE officially opened on 24 September 1966 and the first rockets were launched the following November. This was to be the start of several years of hectic activity at the range. The programme came to an abrupt end in 1972 as part of the preparations for the creation and expansion of ESA, but the memories remain vivid for many of the rocketeers. An enthusiastic group, some still with ESA and others working or retired in various European countries, marked the 30th Anniversary with a reunion at ESRANGE from 28 August to 1 September this year. ESRANGE past and present A total of 152 sounding rockets was launched from ESRANGE between 1966 and 1972: 72 under ESRO's aegis and 80 within national programmes. Most flew during auroral activity to study the effects of energetic electrons and ions that had been accelerated in the distant magnetosphere before precipitating along magnetic field lines in the auroral atmosphere. The beautiful auroral displays are the visible manifestations of a region in space uniquely suited to studying these processes at work, both near and beyond the Earth.

2 Figure 1. Preparation of a Centaure rocket for the first launch campaign at ESRANGE in late 1966 Most of ESRANGE's permanent staff hailed from countries with previous sounding rocket experience, such as the United Kingdom, France, Germany, Norway and Sweden, but other nationalities added colour to Kiruna's new community. Life became more hectic during the campaigns when the payload teams from ESTEC, and the experimenters from various ESRO Member States, joined the permanent staff. This made it necessary to make use of Hotel Albert, a primitive wooden barrack built next to the main ESRANGE building - an unforgettable experience for many visitors. Launching auroral rockets often required long vigils during cold winter nights, and it was not unusual for a campaign, when no suitable launch conditions appeared, to be moved to the following winter. Several national space agencies also exploited ESRANGE for rocket and balloon experiments. This was particularly true of Germany and Sweden, which had sizable national rocket programmes at that time. It came as an unpleasant surprise when ESRO's Council decided in 1971 that the rocket programme would end the following year in order to clear the decks for a wider range of activities under the soon-to-be-born ESA. Most of the ESRO staff, and many of the experimenters, felt that this sudden end to a successful and smooth-running programme, with a quick turnaround time, was most unfortunate.

3 ESRANGE was turned over to Swedish control, leaving it with a much smaller programme and, consequently, a highly uncertain future. The members of this year's reunion were therefore delighted to find that not only has ESRANGE survived, but it is thriving thanks to new rocket programmes and other activities as a co-ordinated European programme under the responsibility of national space agencies. Recent years have seen a new class of rocket flights: microgravity experiments on high-altitude carriers. Microgravity research on Skylark 7 and the 15 t Maxus, first launched in May 1991, has brought ESA back to ESRANGE. The steerable Maxus can reach close to 1000 km and return within 7 km of the predicted impact point. Cassini's Huygens Probe, which will land on Titan in 2004, was drop-tested by ESA at ESRANGE. A balloon carried Huygens up to 38 km, where it was released to demonstrate deployment and parachute performance. The Probe was successfully recovered a standard procedure at ESRANGE. Figure 2. Cassini's Huygens probe, recovered after its ESRANGE drop test in 1995

4 ESRANGE's continuity has also been assured by the operation of numerous Earthobservation and science satellites for ESA and many agencies worldwide. ESA's Earth-observation ground station near ESRANGE adds to the technical and social environment in the gently sloping hills 50 km northeast of Kiruna. The 30th Anniversary Reunion Some 50 people travelled to Kiruna for the reunion, from ESA establishments, Belgium, Germany, Italy, Spain, the United Kingdom and France, and several ex- ESRANGE staff came from various corners of Sweden. About 60 apologies were received from ex-rocketeers unable to join the reunion; inspired letters were received from Albert Le Bras, the first ESRANGE Director, and Pierre Blassel, who was responsible for all technical installations. On Thursday 29 August, ESRANGE provided a full day's programme for the visitors. They were welcomed by the present Head of ESRANGE, Jan Englund, and then staff members gave presentations of past and present range activites. Professor Bengt Hultqvist gave an historical overview of the events leading up to the establishment of ESRANGE; the early existence of what was then called the Kiruna Geophysical Observatory was certainly an important element in that process. A tour of the present facilities followed. In the evening a dinner was held in the Kiruna Town Hall for the visitors and ESRANGE staff. The Mayor of Kiruna reminded the guests that Kiruna is the largest 'community' in the World, being half the size of Switzerland! There was also a 'ceremonial launch' to bring back old memories. A miniature Zenith was successfully launched to an altitude of several hundred metres. This model of one of ESRO's rockets was kindly provided by Nova Models of Florida, USA. The reunion was also an opportunity to remember colleagues who have passed away. A well-known veteran from the early ESRO rocket campaign, Steve Pooley, died earlier this summer. His memory was honoured by a one-minute silence, which also served as a mark of respect for other deceased staff.

5 Figure 3. Participants at the ESRANGE Reunion

6 Figure 4. Launching the Skylark 7/Texus-3 mission from ESRANGE in April 1980

7 Figure 5. Reliving old memories: launching the Zenith model rocket

8 Figure 6. The reunion participants picnicking on a mountain overlooking Abisko near the Swedish/ Norwegian border The ESRO Sounding Rocket Programme - early lessons for ESRO and ESA In 1989, the then Director General of ESA, Reimar Lüst, said in relation to the 25th Anniversary of the first ESRO sounding rocket flight, 'The spirit of those who worked on the early sounding rockets still pervades much of the European space activities today. It is an excellent heritage: long may it remain so.' These words have special significance coming from an ex- rocketeer whose space career began with rocket experiments at ESRANGE.

9 Figure 7. View over ESRANGE during a Texus rocket launch ESRO provided the first test of European co-operation in this field, proving successful in terms of technical performance, management and programmatics. An important element was that technical teams could design, build and test a significant proportion of the rocket payloads at ESTEC; the rest was built by industry. This increased the level of knowledge and experience in the Agency and formed the basis for a sound management structure. Many engineers were forced to leave ESRO after the last rockets departed in ESRANGE could still offer some employment to the Swedish staff, and a fair number of other nationalities found new positions at the various ESRO establishments, the majority of them at ESTEC. For many engineers, the experience gained on sounding rockets was a stepping stone to longer-term careers in ESA. Many made valuable contributions to satellite and manned space projects due in part to the technical insight gained by their close involvement in ESRO's rocket projects. Unfortunately, many have either retired or are close to retirement, leaving few with hands-on experience for future ESA projects. The sounding-rocket programme made it possible for scientists from all Member States to be involved and gain their first experience in a space venture. The rocket projects, taking only a few years from concept to flight, provided ideal PhD themes, and many well-known European space scientists launched their academic careers on rockets. Building experiments for flight was a new challenge for

10 scientific laboratories in the mid-1960s. Colleagues on NASA programmes were initially far ahead of the Europeans, as few laboratories here had the knowledge required to produce satellite hardware. The sounding-rocket experience changed all that: European groups quickly grasped the intricacies of space instrumentation and gradually gained the confidence and knowledge to be the equals of their international colleagues, even on the more challenging space missions. It is a telling fact that most laboratories involved in the current ESA Scientific Programme were involved at some time in a rocket programme run by ESRO or a national space agency. The scientific knowledge obtained via the ESRO sounding-rocket programme at ESRANGE provided new insights into the dynamic auroral ionosphere and its coupling to sources of energetic particles. Today, the early results from rocket measurements in the polar atmosphere have gained renewed relevance for the understanding of the depletion of the ozone layer. These results also formed the basis for later international and national auroral satellite missions. Even now, there are unsolved mysteries in the ionosphere and atmosphere above ESRANGE at heights reachable only by rockets and balloons.