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5 Summary of Technology Development Needs SOLAR AND HE[IOSPEERIC 1. Solar and heliospheric physics requires in situ plasma measurements from close to the solar surface to the interstellar medium. Conventional propulsion cannot be used for the following orbits: (a) an elliptical orbit for the solar probe with a 1-year pe- riod; (b) a circular or near-circular orbit for the heliosynchronous satellite at 30 solar radii; and (c) at least a 4~km/s velocity for a spacecraft leaving the heliosphere. Solar Electric Propulsion (SEP) or similar methods need de- velopment to have a technology available by 1995. It should be noted here that low-thrust propulsion is also needed for many comet and asteroid rendezvous missions. 2. In connection with spacecraft coming close to the Sun, thermal isolation techniques need to be investigated. For the interstellar probe, one must develop nuclear electric propulsion or a perihelion thruster. 3. Multilayer coating will allow the construction of normal incidence mirrors for the x-ray/ultraviolet and x-ray regime that will result in unprecedented resolution. Present-day techniques are not applicable to large-diameter (about 1 m) mirrors. Active 54

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55 mirror surface control techniques and new telescope stabilization methods need to be researched. 4. A Lagrangian platform would be of use to many disciplines. It should be studied In terms of instrument volume, weight, power, and serviceability. MAGNETOSPlIERIC PHYSICS 1. Systems will need to be developed that will allow the plasma populations to be "imaged" so that global models of mag- netospheric structure can be tested directly. 2. The development of radiation-resistant sensors and elec- tronic components that can extend the lifetune of the Jupiter Polar Orbiter mission is needed. 3. In order to be able to deploy a large network of spacecraft to map current systems in the magnetosphere, the costs must be tightly controlled. Cost-reduction techniques should be investi- gated for the development of sunple identical spacecraft. 4. Since the Jupiter Polar Orbiter spacecraft will necessar- ily fly through the jovian ring system, enhanced dust protection techniques will have to be developed. 5. Techniques and systems needed to carry out active plasma physics experiments (interactions of plasmas with waves, beams, gases, and dust) on Shuttle/Spacelab and/or Space Station should be developed.

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