A document proposes a two-step laser ranging technique for precise tracking of a coasting interplanetary spacecraft to determine the degree to which leakage of fuel, solar wind, and/or solar-radiation pressure causes it to deviate from a purely gravitational trajectory.
Such a determination could contribute to the precision of a test of a theory of gravitation. In the technique, a proof mass would be released from the spacecraft. By use of laser ranging equipment on the spacecraft and retroreflectors attached to the proof mass, the relative position of the spacecraft and proof mass would be determined.
Meanwhile, the position of the spacecraft relative to the Earth would be determined by ranging by use of a laser transponder. The vector sum of the two sets of ranging measurements would be the position of the proof mass relative to the Earth. Unlike the acceleration of the spacecraft, the acceleration of the proof mass should not include a residual component attributable to leakage of fuel. In addition, the effects of solar radiation and solar wind on the proof mass could be minimized by releasing the proof mass into the shadow of the spacecraft.
This work was done by Talso Chui and Konstantin Penanen of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Mechanics category.
NPO-40733
This Brief includes a Technical Support Package (TSP).
Two-Step Laser Ranging for Precise Tracking of a Spacecraft
(reference NPO-40733) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package from NASA's Jet Propulsion Laboratory (JPL) detailing the development of a novel two-step laser ranging technique aimed at enhancing the precision of spacecraft tracking. This innovation is particularly relevant for future deep space missions that utilize laser transponders and nuclear propulsion technologies.
The motivation behind this development stems from the limitations of traditional tracking methods, which rely on radio waves or microwaves. Notably, the document references the Pioneer anomaly, where the trajectories of the Pioneer 10 and 11 spacecraft exhibited unexpected behavior that could not be explained by existing gravitational models. This discrepancy highlighted the need for more accurate tracking methods, which the two-step laser ranging technology aims to address.
The two-step laser ranging technique is designed to significantly improve the precision of spacecraft trajectory tracking, potentially reducing uncertainties in celestial dynamics by orders of magnitude. This advancement could lead to better knowledge of planetary orbits, enhanced spacecraft navigation, and more precise tests of gravitational theories.
The document outlines the current status of the technology, indicating that it is still in the conceptual phase, with ongoing error analysis to refine the system. It emphasizes that while the invention is fixed in its final form, further development is necessary to bring it to practical application. The potential applications of this technology include precision navigation for satellites and other space missions.
Additionally, the document notes that there are plans to present this technology at an upcoming conference on particle and space physics, indicating a commitment to sharing advancements with the broader scientific community. The technology has not yet been utilized outside of JPL, and there are no existing commercial applications, but the potential for future use in aerospace activities is significant.
In summary, the document presents a promising advancement in spacecraft tracking technology through the two-step laser ranging technique, which could revolutionize how spacecraft are navigated and studied in deep space, ultimately contributing to a deeper understanding of celestial mechanics and gravitational theories.
