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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Laser radar for spacecraft guidance applications

A flight qualified laser radar called LAMP (LAser MaPper) is under development at JPL. LAMP is a guidance and control sensor that can form 3 dimensional images of its field of regard. This paper describes the detailed design of the LAMP sensor.

LAMP laser radar laser range finder↗
NASA NTRS1964

Guidance analysis.

Unmanned spacecraft guidance policy and orbit determination, using linear perturbation theory and minimum variance estimation

SPACECRAFT GUIDANCE↗
NASA NTRS1966

Gemini - Guidance and control.

Gemini guidance and control, discussing design, ground monitoring, launch and flight guidance, spacecraft instrumentation, maneuvering, etc

SPACECRAFT GUIDANCE↗
NASA NTRS2008

Enhanced Pseudo-Waypoint Guidance for Spacecraft Maneuvers

An enhanced version of the scheme reported in "Pseudo-Waypoint Guidance for Proximity Spacecraft Maneuvers" (NPO-42753), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 73 was developed. To recapitulate: the scheme provides algorithms for guidance and control (G&C) of a spacecraft maneuvering near a small astronomical body. The open-loop guidance problem is solved in advance or in real time by use of the pseudo-waypoint generation (PWG) method. Feedback control is implemented to track PWG trajectories, in a manner that enables updating of G&C in a model-predictive manner. The scheme includes silent periods following each thruster firing. The original version of the scheme provides for a fire-first, followed-by-silence sequence, which is disadvantageous in that the silence after final firing precludes reduction of any remaining velocity error -- an unacceptable result in the case of a maneuver for which a specific final velocity is required. In the enhanced version, the scheme is augmented with a fire-second technique, so that the final velocity can be established with a much higher precision because both the guidance and feedback firing can be performed and ceased at the final maneuver time.

Carson, John↗
NASA NTRS2006

A Simple, Powerful Method for Optimal Guidance of Spacecraft Formations

One of the most interesting and challenging aspects of formation guidance law design is the coupling of the orbit design and the science return. The analyst's role is more complicated than simply to design the formation geometry and evolution. He or she is also involved in designing a significant portion of the science instrument itself. The effectiveness of the formation as a science instrument is intimately coupled with the relative geometry and evolution of the collection of spacecraft. Therefore, the science return can be maximized by optimizing the orbit design according to a performance metric relevant to the science mission goals. In this work, we present a simple method for optimal formation guidance that is applicable to missions whose performance metric, requirements, and constraints can be cast as functions that are explicitly dependent upon the orbit states and spacecraft relative positions and velocities. We present a general form for the cost and constraint functions, and derive their semi-analytic gradients with respect to the formation initial conditions. The gradients are broken down into two types. The first type are gradients of the mission specific performance metric with respect to formation geometry. The second type are derivatives of the formation geometry with respect to the orbit initial conditions. The fact that these two types of derivatives appear separately allows us to derive and implement a general framework that requires minimal modification to be applied to different missions or mission phases. To illustrate the applicability of the approach, we conclude with applications to two missions: the Magnetospheric Multiscale mission (MMS) , and the Laser Interferometer Space Antenna (LISA).

Hughes, Steven P.↗
NASA NTRS2005

A Simple, Powerful Method for Optimal Guidance of Spacecraft Formations

One of the most interesting and challenging aspects of formation guidance law design is the coupling of the orbit design and the science return. The analyst s role is more complicated than simply to design the formation geometry and evolution. He or she is also involved in designing a significant portion of the science instrument itself. The effectiveness of the formation as a science instrument is intimately coupled with the relative geoniet,ry and evolution of the collection of spacecraft. Therefore, the science return can be maximized by optimizing the orbit design according to a performance metric relevant to the science mission goals. In this work, we present a simple method for optimal formation guidance that is applicable to missions whose performance metric, requirements, and constraints can be cast as functions that are explicitly dependent upon the orbit states and spacecraft relative positions and velocities. We present a general form for the cost and constraint functions, and derive their semi-analytic gradients with respect to the formation initial conditions. The gradients are broken down into two types. The first type are gradients of the mission specific performance metric with respect to formation geometry. The second type are derivatives of the formation geometry with respect to the orbit initial conditions. The fact that these two types of derivatives appear separately allows us to derive and implement a general framework that requires minimal modification to be applied to different missions or mission phases. To illustrate the applicability of the approach, we conclude with applications to twc missims: the Magnetospheric Mu!tiscale mission (MMS), a,nd the TJaser Interferometer Space Antenna (LISA).

Hughes, Steven P.↗