Design considerations for Surveyor guidance.

Cheng, R. K.; Conrad, David A.; Meredith, C. M.

doi:10.2514/3.28709

Cited by 22 publications

(6 citation statements)

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“…A lot of scientists and engineers confirmed considerable interests in the past couple of decades [1,2,3,7,8,9]. Two-dimensional solution for lunar descent and landing from orbital speed conditions is presented in [4].…”

Section: Introductionmentioning

confidence: 99%

Moon Landing Trajectory Optimization

Mehedi¹,

Islam²

2016

ijacsa

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Abstract-Trajectory optimization is a crucial process during the planning phase of a spacecraft landing mission. Once a trajectory is determined, guidance algorithms are created to guide the vehicle along the given trajectory. Because fuel mass is a major driver of the total vehicle mass, and thus mission cost, the objective of most guidance algorithms is to minimize the required fuel consumption. Most of the existing algorithms are termed as "near-optimal" regarding fuel expenditure. The question arises as to how close to optimal are these guidance algorithms. To answer this question, numerical trajectory optimization techniques are often required. With the emergence of improved processing power and the application of new methods, more direct approaches may be employed to achieve high accuracy without the associated difficulties in computation or pre-existing knowledge of the solution. An example of such an approach is DIDO optimization. This technique is applied in the current research to find these minimum fuel optimal trajectories.

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Section: Introductionmentioning

confidence: 99%

Moon Landing Trajectory Optimization

Mehedi¹,

Islam²

2016

ijacsa

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“…To design the guidance and control law, two factors should be taken into consideration to ensure missions success: a low touch down velocity and a vertical attitude on the planetary surface. Many studies on guidance for soft landing have been reported [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. These guidance laws can be divided into two catalogues: 1.)…”

Section: Introductionmentioning

confidence: 99%

“…These guidance laws can be divided into two catalogues: 1.) Gravity-Turn guidance law [1][2][3][4][5][6][7][8][9][10]12]. Such a descent profile requires that the vehicle thrust vector is oriented opposite to the instantaneous velocity vector along the descent trajectory.…”

Section: Introductionmentioning

confidence: 99%

“…Such a descent profile requires that the vehicle thrust vector is oriented opposite to the instantaneous velocity vector along the descent trajectory. To develop a gravity-turn guidance law, an approximate form solution is first required [1][2][3][4], and a control law is then designed to track this predefined profile [3][4][5][6][7][8][9]. The following methods have been developed successfully: linear feedback control [5,6], nonlinear control via nonlinear transformation [7], direct adaptive control (DAC) [8], feedback linearization [9] and methods using Lyapunov stability theory [3,4].…”

Section: Introductionmentioning

confidence: 99%

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Analytical Landing Trajectories for Embedded Autonomy

Macdonald

McInnes

et al. 2010

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…The great benefit of using gravityturn descent is to guarantee an upright landing and optimize fuel consumption. 8) The lunar guidance scheme takes a horizontally oriented spacecraft from orbital speeds at a point of hundreds of kilometers from the desired landing point to an almost vertical orientation and very low speed. Implemented guidance schemes for lunar landing date back to the Apollo era.…”

Section: Introductionmentioning

confidence: 99%

Advanced Guidance Scheme for Lunar Descent and Landing from Orbital Speed Conditions

Mehedi

Kubota

2011

Trans. Japan Soc. Aero. S Sci.

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Precise landing technology is one of the most important technologies for future lunar or planetary exploration missions. To achieve a precise landing, an advanced guidance scheme is necessary. This paper outlines a comparison of different solution methods for motion control equations utilized in guidance schemes for lunar descent, and proposes an advanced solution that allows a full depiction of descent vehicle motion from orbital states down to the final landing event. In the conventional solution methods, there exist some poor assumptions such as during descent, constant vertical gravitational acceleration is the only other force acting on the descent vehicle. This inadequate postulation limits the validity of the system solutions within a very low altitude terminal descent area; that is, close to the lunar surface. In this paper, an advanced descent solution is proposed where the centrifugal acceleration term is retained along with the gravitational acceleration term. It allows a complete representation of the descent module motion from orbital speed conditions down to the final landing state. Mathematical derivations of the new scheme are verified in terms of a conventional scheme, and comparative simulation results for a fully integrated solution, conventional schemes and a proposed advanced scheme are demonstrated to test the performance.

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Design considerations for Surveyor guidance.

Cited by 22 publications

References 1 publication

Moon Landing Trajectory Optimization

Moon Landing Trajectory Optimization

Analytical Landing Trajectories for Embedded Autonomy

Advanced Guidance Scheme for Lunar Descent and Landing from Orbital Speed Conditions

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