This volume contains original publications from the 1st International Workshop on Space Radiation Research and 11th Annual NASA Space Radiation Health Investigators' Workshop, held on May 27 - 31, 2000 in Arona (Italy). The radiobiology of protons and heavy ions irradiation continues to grow as a scientific discipline with important applications in space radiation protection, cancer therapy, biological countermeasures, and the basic understanding of DNA, cellular, and tissue responses. Because of the unique characteristics of these radiation fields, there is also substantial scientific interest in several areas of physics including nuclear reaction and transport theories, dosimetry and particle detection, and radiation shielding. The enthusiasm of this growing field was reflected this international meeting sponsored by the Italian Space Agency (ASI), the European Scientific Institute (ISE), and NASA. There were 152 registered participants from 14 countries that participated in the meeting.

The meeting was divided into 11 plenary sessions, which included 60 oral presentations, with an additional 52 contributed poster presentations. Jurgen Kiefer from Germany provided the opening talk in the beautiful church of Santi Martiri and reviewed challenges for space radiation research in the new Millennium. The theme of research challenges for the future for space radiation protection, therapy with heavy ion beams and radiobiology studies was continued in the opening session with papers from Francis Cucinotta from the US, Gerhard Kraft of Germany, and Eric Hall from the US, respectively. Special memorial presentations for Cornelius Tobias and Harold Rossi were presented in this opening session. The opening session concluded with presentations describing existing or planned accelerator facilities for radiobiology studies at Brookhaven National Laboratory by Derek Lowenstein, Loma Linda University by Greg Nelson, the LNL facility by Luigi Tecchio, and the Italian Hadrontherapy Project was described by Ugo Amaldi.

The main body of the meeting was divided into the three areas of basic studies in radiobiology related to risk assessment or therapy, the physics of protons and heavy ion interactions with a strong focus on shielding studies, and lastly space flight measurements. Experimental studies of the initial damage and repair of DNA by heavy ions were discussed in several papers by P. Cooper, B. Sutherland, A. Kronenberg, and others. Such data is important for validation of computational models of DNA damage as described in papers by A. Chatterjee, H. Nikjoo, A. Ponomarev, and A. Ottolenghi and their collaborators. The pathways leading from initial DNA insult to manifestation of biological harm were considered in several experimental papers that described genomic instability in vitro (M. Khadim, E. Goodwin, A. Brooks) or in vivo (R. Ullrich). A major focus of the meeting and for the future is the understanding casual relationships between initial DNA damage and rejoining, mutagenesis, and chromosomal instability with responses in tissues and animal. New experimental results with heavy ion beams on tissue and animal responses were discussed during the meeting in papers by M. Barcelles-Hoff, F. Burns, B. Rabin, and J. Joseph. Several shorter papers also discuss new data on these topics in radiobiolgy.

A special session on Space Radiation Research in Italy, chaired by Dr. Carlo Bonifazi of ASI, highlighted several studies on molecular responses to radiation including alterations by microgravity and shielding in papers by E. Del Terra, P. Mosesso, G. Palumbo, and M. Durante. Other Italian projects related to cosmic radiation measurements and shielding were described by P. Spillantini, L. Narici, and G. De Angelis. M. Belli presented a history of radiobiology research in Italy. In related papers, C. Baumstark-Khan of Germany and T. Ohnishi of Japan considered radiobiology data obtained in space flight. Such exploratory studies of gene expression in space will be useful after ground-based understanding of the responses the many complicated protein regulatory networks that control cellular outcomes are obtained. The application of radiobiology research for developing improved understanding and methods for radiation cancer therapy was discussed by R. Katz of the US and K. Ando of Japan.

The second major theme addressed by the meeting was the role of physical interactions and shielding in space radiation protection and cancer therapy. Methods used in radiation transport were discussed by J. Wilson from the US, A. Ferrari from Italy, and P. Nieminen of ESA. The measurement of physical interaction data was discussed in a paper by J. Miller from the US. The availability of proton and heavy ion accelerators was shown to be essential for establishing physical cross section data bases and validating predictive codes as they are for radiobiology studies. Several related papers discussed similar themes during the meeting including the application to specific space missions such as the International Space Station (ISS) and for Mars' exploration.

The meeting concluded with a session on space flight measurements and radiation protection that focused on the ISS. G. Reitz, G. Badhwar, and V. Petrov reviewed the dosimetry to be used on the ISS by the European Space Agency, NASA, and the Russian Space Agency, respectively. The final talk of the meeting was from Michael Fry who reviewed the basis for radiation protection limits for astronauts and discussed focus areas for the future. Included in this paper were the new recommendations from the US National Council of Radiation Protection and Measurements for career radiation dose limits.

The organization of the meeting benefited greatly by both the scientific committee (U. Amaldi, K. Ando, M. Belli, R. Cherubini, F. Cucinotta, G. Gialanella, G. Kraft, W. Schimmerling, and B. Sutherland) and the Organizing Committee (R. Cirio, V. Cotonei, M. Durante, and A. Hegedus). We wish to extend a special note of appreciation to Agnes Hegeus, the students from Naples and Turin (M. Cappiello, S. Chauvie, V. d'Alesio, R. Gotta, R. Nigro, and F. Panichi), and Gail Pacetti and Tonya Hardin from Houston. Their valuable contributions and assistance made the meeting a memorable and successful one. Special thanks are due to Massimo Cappiello and Danilo Esposito (both at the University of Naples "Federico II") for handling the manuscripts included in this book.

The Guest Editors Roberto Cirio, Francis Cucinotta, and Marco Durante