Mars Science Laboratory Interplanetary Navigation

TLDR

The Mars Science Laboratory (Curiosity) launched in November 2011 and landed in Gale Crater on Mars in August 2012. The mission aimed to deliver the spacecraft to the correct entry interface point above Mars’ atmosphere and to precisely determine its position during atmospheric entry. During descent, the spacecraft used guidance before parachute deployment to reduce landing dispersions, relying on accurate delivery to the entry interface and an updated spacecraft state to initialize the descent guidance system. Orbit determination during cruise achieved meter‑level accuracy, predicting the spacecraft’s line‑of‑sight within a few meters after one week and landing 200 m from the predicted entry point, a precision enabled by spacecraft design, tracking data processing, dynamical modeling, and navigation filtering, which in turn ensured a precise landing and overall mission success.

Abstract

The Mars Science Laboratory, also called Curiosity, is a rover mission that launched on 26 November 2011 and landed on Mars 6 August 2012 in Gale Crater. The main challenges for the interplanetary navigation of the mission were to deliver the spacecraft to the correct interface point above the atmosphere of Mars and to accurately tell the spacecraft where it was as it entered the atmosphere. The spacecraft used guidance during its descent to Mars before the deployment of the parachute in order to minimize landing dispersions, resulting in a smaller landing zone that was closer to terrain of high scientific interest. This required an accurate delivery of the spacecraft to the entry interface and an update of the spacecraft state at entry, which was used to initialize the descent guidance system. Orbit determination during cruise was very accurate, being able to predict the line-of-sight position of the spacecraft after one week to within a few meters during the final weeks of approach. The spacecraft hit the top of the Martian atmosphere just 200 m from where it had been predicted to enter more than six days earlier, when it was still 2.6 million km away from Mars. This excellent level of accuracy was achieved by a combination of factors, including spacecraft characteristics, tracking data processing, dynamical modeling choices, and navigation filter setup. The accurate interplanetary navigation contributed to the very precise landing performance and to the overall success of the mission.