[1] The Phoenix mission, launched on 4 August 2007, landed in the far northern plains of Mars on 25 May 2008. In order to prepare for the landing events and the 90-sol mission, a significant amount of work has gone into characterizing the atmospheric environment at this location on Mars for northern late spring through midsummer. In this paper we describe the motivation for the work and present our results on atmospheric densities and winds expected during the Phoenix entry, descent, and landing, as well as near-surface pressure, temperature, winds, surface temperature, and visible optical depth expected over the course of the science mission.

Gravity-assist trajectories to Jupiter, launching between 1999 and 2031, are identi ed using patched-conic techniques. The classical trajectories, such as the Venus-Earth-Earth gravity assist, and many less conventional paths, such as Venus-Mars-Venus-Earth, are examined. Flight times of up to about seven years are considered.The D V-optimized results con rm that Venus-Earth-Earth is the most effective gravity-assisttrajectory type, with launch opportunities occurring almost every year and launch vis viva for ballistic trajectories as low as 9 km 2 /s 2 . If the Earth is excluded as a yby body, Venus-Venus-Venus gravity assists are typically the best option, with launch vis viva for ballistic trajectories as low as 30 km 2 /s 2 , although in some years nonconventionalpaths are better, such as a ballistic Venus-Mars-Venus-Venus trajectory in 2012, with a launch vis viva of 16 km 2 /s 2 . Nonconventional paths, such as Venus-Mars-Venus-Earth with a 3.7-year ight-time trajectory in 2021, can occasionally decrease the time of ight signi cantly, at very minor D V cost, when compared with the classical types.

Gravity-assist trajectories to Jupiter, launching between 1999 and 2031, are identified using patchedconic techniques. The classical trajectories, such as the Venus-Earth-Earth gravity assist (VEEGA), and many less conventional paths, such as Venus-Mars-Venus-Earth, are examined. Flight times of up to about seven years are considered. The AV-optimized results confirm that VEEGAs are the most effective gravity-assist trajectory type. If the Earth is excluded as a flyby body, Venus-Venus-Venus gravity assists are typically the best option, although at times non-conventional paths are better. These non-conventional paths can occasionally decrease the time of flight significantly, at very minor AV cost, when compared to the classical types.

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