Spacecraft Radiation Research Articles

Upgrading of some instrumentation devoted to increase space radiation environment understanding

Three methods permitting to characterize space and onboard spacecraft radiation environment have been developed and/or upgraded in our laboratories: MDU equipment with a semiconductor detector as sensitive element devoted to register energy deposition spectra in the Si-diode; a spectrometer of the linear energy transfer (LET) based on chemically etched polyallyldiglycolcarbonate (PADC) track etch detectors (TED); and thermoluminescent detectors (TLDs) with different dependences of relative TL yield on the LET of particles transferring their energy in them. We have used all these types of dosimetry equipments onboard spacecrafts since several years and succeeded to treat directly read data in terms of both quantitative and qualitative dosimetry characteristics and deduce from them related radiation risk. During last few years all these three types of detectors have been intensely studied to understand still better their possibilities to characterize space radiation fields. Particularly: 1. Both PADC TED LET spectrometer and TLDs have been exposed in heavier ion beams with LET in water ranging from 1 to about 700 keV/μm with the goal to upgrade their calibration curves; 2. A new method of MDU directly read data has been developed, permitting to measure not only dose in Si-detector, but also to estimate radiation protection quantities and the neutron contribution to the onboard exposure level; 3. All three methods have been tested onboard spacecrafts during several missions. Contribution presents, analyses and discusses the results obtained in items 1–3 and, also, the possibilities of these detectors to help in characterizing radiation fields during longer space missions, above 1 year.

With solar max around the corner, workshop looks at preventing space weather interference

Natural phenomena taking place on the Sun and in the solar wind, magnetosphere, ionosphere, and thermosphere can affect a variety of modern technological systems. Collectively termed “space weather,” these phenomena produce effects ranging from spacecraft charging and radiation damage to geomagnetically induced currents in terrestrial power grids. A subset of space weather phenomena, either generated in direct response to solar disturbances or due to ongoing atmospheric dynamics (ultimately solar driven, as well), takes place in the ionosphere.

Survey of nongravitational forces and space environmental torques - Applied to the Galileo

A detailed survey of nongravitational forces and space environmental torques acting upon the Galileo spacecraft during its interplanetary flight to Jupiter is given. It includes simple analytic equations to model the first-order effect of solar, planetary,)and spacecraft radiation; solar wind; meteoroids; cosmic rays; magnetic fields; Newtonian drag forces; and leakage of the propulsion system. The model parameters are taken from recent spaceflight data. The result is a model of the magnitudes of the disturbing forces and torques. It provides a useful tool for the analysis of the Galileo and future spaceflight missions.

Effect of polarization on spacecraft radiation heat transfer

The fact that polarization affects radiation heat transfer is pointed out and illustrated with calculations for the interreflection of solar energy among spacecraft components. The general case of radiation transfer in an enclosure with account taken of polarization is formulated, and special cases are set up in detail for engineering calculations. These special cases are specular reflection from isotropic and anisotropic solids and one reflection of solar energy from an imperfectly diffuse solid. Qualitative rules are given to guide the engineer in deciding whether or not polarization should be considered.

The Spacecraft Radiation Experiments

The radiation experiments on the Telstar spacecraft were designed to measure the electron and proton particle distributions in the region of space explored by the satellite orbit and to give information on the integral semiconductor radiation damage produced by these particles. A solar aspect experiment is included with the radiation experiments because of its direct importance to solar cell damage results. The design and the hardware for these experiments are described in the present paper. Results of the experiments are included in a companion paper in this issue.