Radiation protection against early and late effects of ionizing irradiation by the prostaglandin inhibitor indomethacin.

Protective effects of indomethacin, a prototype prostaglandin-inhibiting agent, against early and late sequelae of radiation injury (after X-rays or gamma rays) in mice were investigated. The following tissues or organs were examined: hematopoietic tissue, esophagus, jejunum, colon, lung, hair follicles, and tissues involved in the development of radiation-induced leg contractures. In addition, the effect of indomethacin was tested against radiation-induced carcinogenesis. In all experiments, the radiation was delivered as a single dose. Indomethacin led to significant protection of hematopoietic tissue, by a factor of 1.3. There was also some protection against radiation-induced pneumonitis and against radiation-induced carcinogenesis (protection factor of 1.2). The other tissues tested showed no change in their radioresponse after being treated with indomethacin. Thus, indomethacin can act as a radioprotective agent against both early and late sequelae of radiation, but its effect is dependent on the tissue tested. This protection is smaller than that observed with WR-2721. However, indomethacin combined with WR-2721 produced a radioprotective effect greater than the radioprotection achieved by individual treatments.     

The scientific payload of the space-based Solar and Heliospheric Observatory (SOHO)

The space-based Solar and Heliospheric Observatory (SOHO) is a joint venture of ESA and NASA within the frame of the Solar Terrestrial Science Programme (STSP), the first Cornerstone of ESA's long-term programme Space Science — Horizon 2000. The principal scientific objectives of the SOHO mission are: a) a better understanding of the structure and dynamics of the solar interior using techniques of helioseismology, and b) a better insight into the physical processes that form and heat the Sun's corona, maintain it and give rise to its acceleration into the solar wind. To achieve these goals, SOHO carries a payload consisting of 12 sets of complementary instruments which are briefly described here.     

The solar orbiter mission

Approved in October 2000 by ESA's Science Programme Committee as a flexi-mission, the Solar Orbiter will studythe Sun and unexplored regions of the inner heliosphere from a unique orbit that brings the probe to within 45 solar radii (0.21 AU) of our star, and to solar latitudes as high as 38°. This orbit will allow the Solar Orbiter to make fundamental contributions to our understanding of the acceleration and propagation of energetic particles in the extended solar atmosphere. During quasi-heliosynchronous phases of the orbit, Solar Orbiter will track a given region of the solar surface for several days, making possible unprecedented studies of the sources of impulsive and CME-related particle events. The scientific payload to be carried by the probe will include a sophisticated remote-sensing package, as well as state-of-the-art in-situ instruments. The multi-wavelength, multi-disciplinary approach of Solar Orbiter, combined with its novel location, represents a powerful tool for studies of energetic particle phenomena.     

SOHO: The Solar and Heliospheric Observatory

The Solar and Heliospheric Observatory (SOHO), together with the Cluster mission, constitutes ESA's Solar Terrestrial Science Programme (STSP), the first Cornerstone of the Agency's long-term programme Space Science — Horizon 2000. STSP, which is being developed in a strong collaborative effort with NASA, will allow comprehensive studies to be made of the both the Sun's interior and its outer atmosphere, the acceleration and propagation of the solar wind and its interaction with the Earth. This paper gives a brief overview of one part of STSP, the SOHO mission.     

SOHO operations and ground system

SOHO is a joint ESA/NASA mission to study the sun from its interior to, and including, the solar wind in interplanetary space. It is currently scheduled for launch in 1995. After launch SOHO with be operated from the Experiment Operations Facility (EOF) at Goddard Space Flight Center (GSFC). The EOF will consist of facilities for instrument commanding, data reception, data reduction and data analysis. In this paper the operations concepts including instrument ground commanding from the EOF and communications capabilities between the EOF and ground observatories and the public networks in general will be described.     

Solar orbiter, a high-resolution mission to the sun and inner heliosphere

The scientific rationale of the Solar Orbiter is to provide, at high spatial (35 km pixel size) and temporal resolution, observations of the solar atmosphere and unexplored inner heliosphere. Novel observations will be made in the almost heliosynchronous segments of the orbits at heliocentric distances near 45 R and out of the ecliptic plane at the highest heliographic latitudes of 30° – 38°. The Solar Orbiter will achieve its wide-ranging aims with a suite of sophisticated instruments through an innovative design of the orbit. The first near-Sun interplanetary measurements together with concurrent remote observations of the Sun will permit us to determine and understand, through correlative studies, the characteristics of the solar wind and energetic particles in close linkage with the plasma and radiation conditions in their source regions on the Sun. Over extended periods the Solar Orbiter will deliver the first images of the polar regions and the side of the Sun invisible from the Earth.