Dust Hazard Management in the Outer Solar System

Abstract

Most robotic missions to the outer solar system must grapple with the hazards posed by the dusty rings of the gas giants. Early assessments of these hazards led simply to ring avoidance due to insufficient data and high uncertainties on the dust population present in such rings. Recent approaches, principal among them the Cassini dust hazard management strategy, provide useful results from detailed modeling of spacecraft vulnerabilities and dust hazard regions, which along with the range of mission trajectories are used to assess the risks posed by each passage through a zone of potential hazard. This paper shows the general approach used to implement the analysis for Cassini, with recommendations for future outer planet missions.

Twenty years of systems engineering on the Cassini-Huygens Mission

“…One of Cassini's prime science objectives was to characterize Saturn's dust environment and this would not have been achieved if Cassini had elected to avoid all regions which may have posed even a small hazard to the spacecraft [13].…”

“…Early ring models were developed using Pioneer, Voyager, and ground-based data. The models have been regularly updated using Cassini's in-situ measurements of the rings collected by a variety of the science instruments [13]. The dust hazard analysis also included a study of the spacecraft to identify vulnerable external surfaces and components.…”

Skirting Saturn's Rings and Skimming its Cloud Tops: Planning Cassini's End of Mission

“…The dust particles associated with the rings can pose a danger to the spacecraft. In the early 1990s, the Cassini project initiated an effort to assess the hazard posed by ring dust particles to the spacecraft 7 . The effort has continued to date, with ring dust models frequently updated with the latest ring science collected by Cassini.…”

“…The main areas of vulnerability to dust damage on the Cassini spacecraft are the main engines and select areas of the electronics bus 7 . Parts of the electronics bus are behind a single layer of aluminum or thermal louvers and penetration or spalling of the aluminum plate could damage the electronics.…”

Cassini at Saturn Proximal Orbits - Attitude Control Challenges

“…Regions close to the center of the G ring also are considered quite hazardous, as are other regions. 7 Dust hazard risk involves four main factors: (1) the spacecraft hardware; (2) the dust environment where Cassini is traveling; (3) the design of the trajectory itself (avoiding known hazardous regions, for example); and (4) adjusting the orientation of the spacecraft so that hazards can perhaps be minimized. The spacecraft has a variety of vulnerable areas, but to first order the spacecraft electronics bus is considered the most vulnerable region.…”