An amendment to this paper has been published and can be accessed via a link at the top of the paper.

OSIRIS-REx is the first NASA mission to return a sample of an asteroid to Earth. Navigation and flight dynamics for the mission to acquire and return a sample of asteroid 101955 Bennu establish many firsts for space exploration. These include relatively small orbital maneuvers that are precise to similar to 1 mm/s, close-up operations in a captured orbit about an asteroid that is small in size and mass, and planning and orbit phasing to revisit the same spot on Bennu in similar lighting conditions. After preliminary surveys and close approach flyovers of Bennu, the sample site will be scientifically characterized and selected. A robotic shock-absorbing arm with an attached sample collection head mounted on the main spacecraft bus acquires the sample, requiring navigation to Bennu's surface. A touch-and-go sample acquisition maneuver will result in the retrieval of at least 60 grams of regolith, and up to several kilograms. The flight activity concludes with a return cruise to Earth and delivery of the sample return capsule (SRC) for landing and sample recovery at the Utah Test and Training Range (UTTR).

The New Horizons mission, the first mission in NASA's New Frontiers Program, is also the first mission with primary science objectives to explore the Pluto/Charon system. After launch in January 2006 and an interplanetary cruise of more than 9.5 years, New Horizons has completed the approach and flyby of Pluto. This paper presents an overview of the analysis and operational constraints that led to the navigation strategy used. Also presented are operational results for that strategy during this final phase of the prime mission.

The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition, its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected.

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, led by principal investigator Scan C. Solomon of the Carnegie Institution of Washington, is the seventh mission in NASA's Discovery Program. The spacecraft was launched from Cape Canaveral Air Force Station on August 3, 2004, to begin its six-and-one-half-year interplanetary cruise to arrive in orbit about Mercury beginning in March 2011. The cruise phase includes planetary gravity-assist flybys of Earth (in August 2005), Venus (in October 2006 and June 2007), and Mercury (in January and October 2008 and September 2009). This paper describes the navigation results for the period encompassing Venus flyby 2 and focuses on orbit determination results, navigation analyses supporting statistical trajectory correction maneuvers, and maneuver reconstruction results. Also included are discussions of optical navigation tests performed after the encounter and implications derived from Venus flyby results for the upcoming first Mercury encounter.

The New Horizons mission to explore the Pluto/Charon system was launched on January 19, 2006 as the first mission in NASA's New Frontiers Program. The New Horizons mission is led by principal investigator, S. Alan Stem, of the Southwest Research Institute. The project is managed by and the spacecraft was built and is operated by The Johns Hopkins University Applied Physics Laboratory. Navigation for the spacecraft is provided by the Space Navigation and Flight Dynamics Practice of KinetX, Inc., a private corporation. The spacecraft will have its first planetary flyby of Jupiter and its moons on February 28, 2007, and after this the spacecraft will continue for eight-and-one-half years of interplanetary cruise to flyby the Pluto/Charon system on July 14, 2015. This paper gives a description of the navigation system developed for the New Horizons mission, and the navigation results obtained thus far for launch and early interplanetary cruise phases of the mission. Also included are results from calibrating and testing the navigation system, including attitude and small force modeling, trajectory correction maneuver design and reconstruction, and the use of DSN Delta Differential One-way Ranging (Delta-DOR).

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, led by principal investigator Sean C. Solomon of the Carnegie Institution of Washington, is the seventh mission in NASA’s Discovery Program. The spacecraft was launched from Cape Canaveral Air Force Station on August 3, 2004 to begin its six-and-one-half-year interplanetary cruise to arrive in orbit about Mercury beginning in March 2011. The cruise phase includes planetary gravity-assist flybys of Earth (in August 2005), Venus (in October 2006 and June 2007) and Mercury (in January and October 2008, and September 2009). This paper describes the navigation results for the interval from Earth flyby through Venus flyby 1, and focuses on orbit determination results, navigation analyses supporting statistical trajectory correction maneuvers, and maneuver reconstruction results for this interval. Also included are preliminary results from several tests performed for optical navigation imaging and Delta-Differential One-way Ranging (Delta-DOR) tracking data types taken on approach to Venus flyby 1.

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, led by principal investigator Sean C. Solomon of the Carnegie Institution of Washington, is the seventh mission in NASA's Discovery Program. The spacecraft was launched from Cape Canaveral Air Force Station on August 3, 2004 to begin its six-and-one-half-year interplanetary cruise to arrive in orbit about Mercury beginning in March 2011. The cruise phase includes planetary gravity-assist flybys of Earth (in August 2005), Venus (in October 2006 and June 2007) and Mercury (in January and October 2008, and September 2009). This paper describes the navigation results for the interval from Earth flyby through Venus flyby 1, and focuses on orbit determination results, navigation analyses supporting statistical trajectory correction maneuvers, and maneuver reconstruction results for this interval. Also included are preliminary results from several tests performed for optical navigation imaging and Delta-Differential One-way Ranging (Delta-DOR) tracking data types taken on approach to Venus flyby 1.

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission is being flown as the seventh mission in NASA’s Discovery Program. The MESSENGER mission is led by the principal investigator, Sean C. Solomon, of the Carnegie Institution of Washington. The project is managed by and the spacecraft was built and is operated by The Johns Hopkins University Applied Physics Laboratory. Navigation for the spacecraft is provided by the Space Navigation and Flight Dynamics Practice of KinetX, Inc., a private corporation. Navigation for launch and interplanetary cruise makes use of radio metric tracking data from NASA’s Deep Space Network in addition to optical navigation from on-board images of planet flybys. The spacecraft was launched August 3, 2004, to begin its six and one-half year interplanetary cruise leading to rendezvous with and orbit of the planet Mercury beginning in March 2011. Once in orbit, MESSENGER will perform detailed science observations of Mercury for at least one Earth year. This paper gives a description of the navigation system developed for the MESSENGER mission, along with the navigation results obtained thus far for launch and the early interplanetary cruise phase of the mission. Also included are plans for calibrating and testing the navigation system during the remaining years of cruise to prepare for support of the science operations in orbit about Mercury.

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission is being flown as the seventh mission in NASA's Discovery Program. The MESSENGER mission is led by the principal investigator, Sean C. Solomon, of the Carnegie Institution of Washington. The project is managed by and the spacecraft was built and is operated by The Johns Hopkins University Applied Physics Laboratory. Navigation for the spacecraft is provided by the Space Navigation and Flight Dynamics Practice of KinetX, Inc., a private corporation. Navigation for launch and interplanetary cruise makes use of radio metric tracking data from NASA's Deep Space Network in addition to optical navigation from on-board images of planet flybys. The spacecraft was launched August 3, 2004, to begin its six and one-half year interplanetary cruise leading to rendezvous with and orbit of the planet Mercury beginning in March 2011. Once in orbit, MESSENGER will perform detailed science observations of Mercury for at least one Earth year. This paper gives a description of the navigation system developed for the MESSENGER mission, along with the navigation results obtained thus far for launch and the early interplanetary cruise phase of the mission. Also included are plans for calibrating and testing the navigation system during the remaining years of cruise to prepare for support of the science operations in orbit about Mercury.