Atmospheric entry studies for Uranus

Abstract

The present paper describes parametric studies conducted to define the Uranus entry trade space. Two different arrival opportunities in 2029 and 2043, corresponding to launches in 202 1 and 2034, respectively, are considered in the present study. These two launch windows factor in the 84-year orbital period, significant axial tilt, and the wide ring system of Uranus. As part of this study, an improved engineering model is developed for the Uranus atmosphere. This improved model is based on reconciliation of data available in the published literature and covers an altitude range of 0 km (1 bar pressure) to 5000 km. Two different entry scenarios are considered: 1) direct ballistic entry, and 2) aerocapture followed by entry from orbit. For ballistic entry a range of entry flight path angles are considered for probe entry masses ranging from 130 kg to 300 kg and diameters ranging from 0.8 m (Pioneer-Venus small probe scale) to 1.3 m (Galileo scale). The larger probes, which offer a larger packing volume, are considered in an attempt to accommodate more scientific instruments.For aerocapture a single case is studied to explore the feasibility and benefits of this option.

Feasibility and Performance Analysis of Neptune Aerocapture Using Heritage Blunt Body Aeroshells (Pre-print)

“…Previous Neptune aerocapture studies have often been restricted to analysis of a single-point design with limited exploration of the underlying trade space. Multiple aerocapture studies have used a limited number of candidate interplanetary trajectories and vehicle designs to perform aerocapture systems analysis, and quantify the performance benefits compared to propulsive insertion [1,10,11,13,33]. The interplanetary trajectories are often optimized for propulsive insertion, and do not take into account the often differing requirements for aerocapture.…”

Qualitative Assessment of Aerocapture and Applications to Future Missions

“…While increasing the time required to reach the initial science orbit, this would also increase the delivered mass. A 2013 study at NASA Ames Research Center [8] examining the 2012 Planetary Science Decadal Survey (PSDS) [9] atmospheric entry probe mission at Uranus was expanded to include using aerocapture for the orbiter part of that mission and included that more realistic approach for the propulsive-only version of the mission. It concluded that the propulsively inserted version would require a launch mass 42% greater than the aerocaptured version, not 200% greater, but a project manager would still consider that increased payload capacity substantial.…”

A Unified Framework for Aerocapture Systems Analysis

“…Multiple aerocapture studies have used a limited number of candidate interplanetary trajectories and vehicle designs to perform aerocapture systems analysis, and quantify the performance benefit compared to propulsive insertion. 1,[4][5][6][7] The interplanetary trajectories are often optimized for propulsive insertion, and do not take account for the differing requirements for aerocapture. While the increased delivered mass from using aerocapture has been quantified by multiple studies, analyses with a limited set of interplanetary trajectories are not representative of the broader aerocapture design space.…”