Propulsion subsystem design for Jupiter orbiter missions
Jupiter orbiter spacecraft propulsion system design, noting advantages of fluorine/hydrazine propellant combination
Don, J. P.↗
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Radio observations of Jupiter
Jupiter radio observations, measuring nonthermal emission, magnetic field and trapped radiation belts
Alexander, J. K.↗
Preliminary analysis of an atmosphere-entry probe mission to Jupiter
Atmospheric entry probe from flyby mission to Jupiter, considering descent trajectory feasibility and instrument package
Swenson, B. L.↗
Design of a probe for deep penetration into Jupiter's atmosphere
Jupiter probe design and communication for deep penetration into atmosphere, concerning mission phases through entry and descent to sample altitudes
Cross, D.↗
Ablative heat shields for Jupiter entry probes
Jupiter atmosphere entry probes graphite ablative heat shields performance, indicating convective and radiative blockage and graphite sublimation processes in surface heat balance
Lundell, J. H.↗
Scientific questions and measurement approaches for a probe entering the atmosphere of Jupiter
Physical, chemical and biochemical instrumentation and measurements for probe entering Jupiter atmosphere
Seiff, A.↗
Relay-link communications geometry for a Jupiter atmospheric probe
Jupiter atmospheric probe using relay-link communications geometry between probe and flyby spacecraft for 3.5 hr intervals
Fischer, R. B.↗
Characteristics of trajectories that fly by Jupiter and Saturn and return to Earth
Earth-Jupiter-Saturn-earth flyby trajectories, determining mission planning parameters
Anson, K. W.↗
Space Flight Handbooks, Volume 3 - Planetary Flight Handbook. Part 8 - Jupiter Swingby Missions to Saturn, Uranus, Neptune, and Pluto. Supplement - Tabular Trajectory Data
The trajectory data are presented chronologically and are organized by holding the arrival date constant while varying the Earth departure date in increments of 10 days. Upon completion of the specified range of Earth departure dates, the arrival date is incremented and the range of departure dates is repeated. The range of departure and arrival dates and the corresponding increments are given in Table 5-1 for each launch opportunity. It should be noted that the interval in arrival date is increased in the long flight time region where the variation of the trajectory parameters is relatively small. The criteria used for the selection of these dates are, in general: (i) the minimum Earth departure hyperbolic excess speed (across the Earth departure window) shall not exceed 0.65 EMOS and (2) the periapsis radius at Jupiter shall not be less than 0.95 planet radii.
Source record↗
Convective motion and the structure of the Jupiter magnetosphere
The convective motion and its relation to the electric field in the magnetosphere of Jupiter are investigated. It is shown that the electric field is induced in the Jovian ionosphere due to the corotating action of the ionospheric gases and further is communicated into the magnetosphere along the magnetic lines of force which connect between the ionosphere and the magnetosphere. This electric field drives the plasma to corotate with the planet in the magnetosphere. The distribution of the electric field and its effect on the plasma motion is estimated in the magnetosphere. The shape of the magnetosphere is then estimated considering the equilibrium condition. Discussion is given on the equilibrium plasma distribution in the magnetosphere and on the condition for the excitation of wave-particle interaction at the Io orbit.
Sakurai, K.↗
Estimation of microwave absorption in the Jupiter atmosphere
A procedure for estimating the microwave absorption loss of the Jupiter atmosphere is presented. Estimation of microwave absorption by planetary atmospheres involves two different investigative disciplines (1) the determination of an acceptable model of the atmosphere itself and (2) the determination of the microwave attenuation rate applicable to each different volume sample of the atmosphere, and the integration of this loss over the varying radio propagation path for any given entry trajectory to obtain the total loss.
Coombs, W. C.↗
Jupiter radiation test levels and their expected impact on an encounter mission
The upper limit, of electron and proton fluences for a thermoelectric outer planet spacecraft mission in a near-Jupiter environment, for use as radiation design restraints, were extracted from a model of the Jovian trapped radiation belts. Considerations of radiation effects in semiconductor devices were employed to construct simplified radiation test levels based on the design restraints. Corresponding levels, based on the nominal belt models, are one to three orders of magnitude smaller. In terms of expected radiation-induced degradation in semiconductor devices, an encounter with an environment as severe as the design restraints would require hardening the system in order to guarantee high reliability. On the other hand, the nominal levels would only necessitate care in the selection of components and the avoidance of certain semiconductor components.
Barengoltz, J. B.↗
Jupiter trapped radiation belts
Previously developed models for trapped electron radiation belts and trapped proton radiation belts in the Jovian magnetosphere are described. The spatial distribution of flux and the L shell dependence of the characteristic energy are displayed for both models. Based on these models, the fluence accumulated by a Jupiter flyby spacecraft is given in terms of the equivalent 3-MeV fluence for electrons and the equivalent 20-MeV proton fluence. Finally, some impacts of these fluences on outer planet missions are described.
Beck, A. J., Jr.↗
Pioneer F mission to Jupiter
The experimental designs for the Pioneer F mission to Jupiter are described. The spacecraft is designed to make measurements of the planet's atmosphere, radiation belts, heat balance, magnetic fields, moons, and other related phenomena. The mission also characterizes the heliosphere, the interstellar gas, cosmic rays, asteroids, and meteoroids between the earth and 2.4 billion kilometers from the sun.
Allaway, H. G.↗
Electron and proton flux models for Jupiter's radiation belts
Estimates of the energetic particle distribution in Jupiter's radiation belts are presented and are compared with previous estimates. Mathematical expressions are developed for the equatorial electron and proton fluxes, shielded electron and proton dose rates, and radiation lifetimes of electronic circuits. It is calculated that a 1 g/sq cm aluminum shield will screen out all protons of energy less than 27.5 MeV, and a 2 g/sq cm shield will screen out protons less than 40.6 MeV. The radiation lifetimes are based on a maximum permissible dose value of 10 million rads, a value 1/2 to 1/3 of the flux at which electronic circuits begin to fail. Estimated increases in lifetimes by using a 3 x 50 orbit instead of a 3 x 3 orbit, and going from 1 to 2 g/sq cm are given.
Klopp, D. A.↗
A note on the Gledhill model of the magnetosphere of Jupiter
Free-free emission from a constant density, isothermal rectangular of thickness 2 Jupiter radii and side dimensions 2 x 8 radii is considered. It is determined that the free-free emission from the Gledhill model exceeds the flux measured from the planet over the entire microwave spectrum. Consequently the electron density must be considerably less than Gledhill assumed (10 to the 9th power electrons/cu cm). The upper limit to the electron density which can be set by comparing free-free emission with the observed spectrum is approximately 10 to the 7th power electrons/cu cm.
Gulkis, S.↗
The effect of Jupiter's satellites on the diffusion of protons
Proton diffusion data are calculated for the Jovian satellites Amalthea, Io, Europa, Ganymede, and Callisto, assuming an equatorial magnetic field at Jupiter's surface of 10 gauss. The cyclotron radius, bounce period, and drift period are calculated for 1 MeV protons. These characteristics and the proton energy at the satellite, mean life near the satellite before impact, and diffusion time are also calculated for 100 MeV protons which conserve their first adiabatic invariant. The longitudinal distance between successive bounces is of the order of a few satellite radii.
Mead, G. D.↗
Stably trapped proton limits for Jupiter
A general introduction to pitch-angle diffusion for Earth and Jupiter magnetospheres is given. The instabilities which might limit the trapped fluxes in the earth magnetosphere are identified as the interchange or ballooning mode, electrostatic loss cone modes, and electromagnetic ion cyclotron wave. The instability theory of the ion cyclotron wave is discussed. This wave can be unstable only if protons can be in cyclotron resonance with the wave. The instability growth rate is proportional to the cyclotron frequency, the fractional number density of fast particles, and the anisotropy of the fast particle distribution. The critical proton energy is the lowest energy for which the stably trapped limit applies, and is calculated to be 150 MeV at L = 2 and for 10 ion pairs/cu cm. Particles above the critical threshold energy are considered and their stability limit is approximately 3 x 10 to the 10th power/sq cm/sec divided by L to the 4th power.
Kennel, C.↗