tag:blogger.com,1999:blog-270899075443508100.post6400960595520375450..comments2024-01-03T20:28:17.727-08:00Comments on Future Planetary Exploration: More on NASA's New Directions for Planetary ExplorationVan Kanehttp://www.blogger.com/profile/14227978868817989527noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-270899075443508100.post-61978007148157586382011-05-04T15:48:39.658-07:002011-05-04T15:48:39.658-07:00Unfortunately, the greatest hobble to radar would ...Unfortunately, the greatest hobble to radar would be the need to continually articulate the solar panels to be in view of the sun. Reconstructing a chirp from an articulated platform will be a monster of a task--in fact it is the greatest barrier facing the Ganymede orbiter. Simple track patterns are complicated enough given chirp geometries without adding spinning spacecraft. But...there's no real need for an orbiter either for radar to succeed.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-270899075443508100.post-44693803018942319602011-04-20T16:22:29.572-07:002011-04-20T16:22:29.572-07:00Good to see that NASA is trying to get good missio...Good to see that NASA is trying to get good missions out of its tight budget. However, I don't understand why the PSD is reluctant to look at missions to Europa that are less than Flagship level. I have already referenced the White Paper to the Decadal Survey that proposes a series of small Europa Orbiters. Each mission tackles only a few "bites" of the Flagship pie, but does so in a financially and technically sustainable manner. I guess that we can wait until "the budget picture improves sufficiently to add a Flagship to the budget." How long will that be? 20 years? 40 years? <br /> Or we can accept that the first Europa Orbiter MUST be FBC in philosophy. If the Europa community will not demand that the first Europa Orbiter must have every possible instrument onboard, then perhaps we can return to that moon in the near future and begin to learn its secrets. <br /> One of the suggestions of the Decadal White Paper was that the series of smaller, cheaper Europa Orbiters utilize solar power instead of RTG's. With your report that the FY2011 law does not re-start Pu-238 production, this suggestion looks reasonable. The presence of solar panels will put limits on the payload and the mission, but it does provide several advantages. Take a look at page 5 of the 2007 report, "Solar-Powered Europa Orbiter Design Study," by Eliot and Langmeier. They point out that the orbit required for a solar-powered mission "could allow radar to achieve its objectives sooner." Also, the orbit would allow for better imaging of Europa's morphology. In other areas, there is little or no science impact.Phil Horzempahttps://www.blogger.com/profile/16877760318970050320noreply@blogger.com