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).

Navigation studies of the required statistical maneuvers in the Pluto approach phase of the New Horizons mission have been performed. Analysis of the spacecraft position knowledge and control errors, with varying number and placement of the final maneuvers from 100 to 10 days prior to Pluto closest approach, were simulated. The effect of varying the orbit determination data cutoff prior to the maneuver design, an important operational consideration, was characterized. A Monte Carlo analysis was performed based on orbit determination knowledge errors, based largely on images obtained from the Long Range Reconnaissance Imager (LORRI), and required maneuver execution errors to investigate uncertainties in the control to the Pluto B-plane target, as well as the delta-v expended. A comparison of knowledge and control requirements is made, and an optimal maneuver strategy is determined.

This paper describes the results of an analysis to update the navigation uncertainties in time of flight expected for the New Horizons spacecraft on the approach to Pluto. This updated analysis incorporates the effects of the newly discovered satellites, Nix and Hydra, on the Pluto approach uncertainties and utilizes the latest optical navigation (OpNav) image schedule. The required Pluto approach navigation accuracy for New Horizons depends on the desired accuracy of several key geometric parameters of interest to science. Examples are science instrument pointing angles and accomplishing Pluto and Charon occultations of the Earth during the Pluto flyby. In particular, science would benefit if the time of flight error can be reduced. In this paper, the knowledge of spacecraft position along the trajectory, or time of flight error, for various options of processing OpNav images of Pluto and its satellites is presented. The OpNav scenarios are part of an overall navigation plan that includes the use of DSN radio metric data and current assumptions on a priori uncertainties for the Pluto system ephemerides.

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.

In January 2006, the Stardust spacecraft will deliver its Sample Return Capsule (SRC) to the recovery site at the Utah Test and Training Range (UTTR) in N. Utah. Stardust will return dust samples from comet Wild 2 collected in January 2004, as well as interstellar dust collected at earlier epochs in heliocentric orbit. During Earth return, the trajectory will be perturbed by small firings of the spacecraft reaction control thrusters. Calibration of these firings is essential to ensure meeting Earth entry requirements. This paper will describe such calibrations performed between superior conjunctions in June-July 2003 when Stardust was about 1 AU from the Sun. Results of their subsequent analysis indicate that although more work remains to be done, modifications of the maneuver execution sequences and attitude transition strategies greatly increase the chances of mission success.

Maneuver design processess, including contingency plans and maneuver performance characteristics are discussed in this paper.

Stardust, NASA's first dedicated sample return mission to a comet, successfully flew through the comet dust around Wold2 on January 2, 2004. The spacecraft flew within 236 km of the comet, meeting the mission requirement of 250+/- 50 km on flyby distance. Stardust collected dust particles and took several images of the comet while flying close to Wild2. The spacecraft will return to earth with the comet samples on January 15, 2006. To accomplish the above objective, a large Deep Space Maneuver (DSM#) was implemented during June 17 and 18, 2003 and a series of Trajectory Correction Maneuvers (TCMs) were also implemented during the 30 days prior to encounter. Both maneuver design and executions were influenced by number of factors including the small body ephemeris uncertainty, predictability of small forces arising from 3-axis attitude limit cycling and spacecraft slews. Maneuver design processes, including contingency plans, and maneuver performance characteristics, are discussed in this paper.

The successful navigation of the Comet Nucleus Tour spacecraft was performed at the Jet Propulsion Laboratory and was conducted with the use of the new noncoherent transceiver technique developed by the Applied Physics Laboratory. Descriptions of the mission and trajectory are provided, followed by a summary of the challenges to navigation. After launch, about six weeks of noncoherent tracking data were acquired while the spacecraft was in the initial phasing orbits about Earth. Unfortunately, radio contact with CONTOUR could not be re-established after the solid rocket motor (SRM) bum that sent the spacecraft onto its interplanetary trajectory. Following the SRM, ground based optical measurements indicated the spacecraft had broken into pieces and was presumed lost. Discussions include the conditioning performed on the 2-way noncoherent Doppler data, the orbit determination process, and the post SRM trajectory reconstruction.

This paper describes the navigation strategy and results for the rendezvous and orbit phases of the NEAR mission.

This paper will show the unique features of navigation and mission design related to orbiting an asteroid and to designing a robust navigation system for the NEAR spacecraft.

When the NEAR Shoemaker spacecraft began its orbit about the asteroid 433 Eros on February 14, 2000, it marked the beginning of many firsts for deep space navigation, Among these were the design and estimation techniques that were necessary to plan and execute an orbit about an irregularly shaped small body. Knowledge of the mass, gravity distribution, and spin state of Eros had to be quickly improved on final approach in order to predict the effect of trajectory correction maneuvers for capture and orbit control around Eros. This required the use of optical landmark tracking, which used pictures of craters on Eros as landmark information, in addition to the more traditional radio metric tracking from NASA's Deep Space Network. The operational use of optical landmark tracking was another navigation first for the NEAR mission. As part of the ongoing effort to improve the Eros physical model, altimeter data from the NEAR laser range instrument was also processed and analyzed. This paper describes the navigation strategy and results for the rendezvous and orbit phases of the NEAR mission. Included are descriptions of the new techniques developed to deal with navigation challenges encountered during the year-long orbit phase. The orbit phase included circular orbits down to 35 km radius and elliptical orbits that targeted overflights to within 2.7 km above the surface. Many of these methods should prove useful for navigation of future missions to asteroids and comets.