The Journal of the Astronautical Sciences

, Volume 55, Issue 3, pp 373–387 | Cite as

A new strategy for lunar soft landing

  • Xu Shijie
  • Zhu Jianfeng


A new strategy based on a windlass device is proposed to deal with the terminal descent of a lunar soft landing mission in this paper. The lunar lander considered here consists of a rover and an assist module (AM) which is equipped with three decelerating thrusters and a lateral thruster. The rover and the AM are connected by a tether (mass is negligible) which winds around the windlass. The dynamics of the terminal descent process is modeled. The guidance laws for the terminal descent phase are derived. Both fuel optimality and lander safety are considered.

The design of the terminal guidance laws in this paper are separated into three stages: firstly, finding the activation point of the decelerating thrusters to minimize fuel consumption; secondly, determining the tensile force of the tether for deployment; and finally, designing the tether’s tensile force to make the rover track the desired velocity-altitude profile. The proposed soft landing strategy needs only the measurements of altitude and vertical velocity. Therefore, it is easy to implement. It effectively prevents the decelerating thrusters’ plume from damaging the lander due to ground interference. Moreover, it is robust against the uncertainties of initial altitude and vertical velocity. Numerical simulation results illustrate the feasibility of the proposed soft landing strategy.


Vertical Velocity Tensile Force Lunar Surface Soft Landing Assist Module 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. [1]
    MEDITCH, J. S. “On the Problem of Optimal Thrust Programming for a Lunar Soft Landing,” IEEE Trans. on Automatic Control, Oct. 1964, pp. 477–484.Google Scholar
  2. [2]
    MCINNES, C. R. “Path Shaping Guidance for Terminal Lunar Descent,” Acta Astronautica, Vol. 36, No. 7, 1995, pp. 367–377.CrossRefGoogle Scholar
  3. [3]
    MCINNES, C. R. “Nonlinear Transformation Methods for Gravity-turn Descent,” Journal of Guidance, Control and Dynamics, 1996, pp. 247–248.Google Scholar
  4. [4]
    D’SOUZA, C. N. “An Optimal Guidance Law for Planetary Landing,” AIAA Paper 97-3709, 1997.Google Scholar
  5. [5]
    UENO, S. and YAMAGUCHI, Y. “3-dimensional Near-Minimum Fuel Guidance Law of a Lunar Landing Module,” AIAA Paper 99-3983, 1999.Google Scholar
  6. [6]
    DAYI, W., TIESHOU, L. I., and HUI, Y. “A Sun-Optimal Fuel Guidance Law for Lunar Soft Landing,” Journal of Astronautics, Vol. 21, No. 4, Oct. 2000, pp. 55–63. (in Chinese)Google Scholar
  7. [7]
    OLGA, B. “Tethered Lander for Planetary Applications,” AIAA Paper 2005-6735, 2005.Google Scholar
  8. [8]
    GRAF, J., THURMAN, S., EISEN, H., RIVELLINI, T., and SABAHI, D. “Second Generation Mars Landed Missions,” Proceedings of IEEE Aerospace Conference, Vol. 1, 2001, pp. 1/243–1/254.Google Scholar
  9. [9]
    MATTINGLY, R., HAYATI, S., and UDOMKESMALEE, G. “Technology Development Plans for the Mars Sample Return Mission,” Proceedings of IEEE Aerospace Conference, March 2005, pp. 982–995.Google Scholar
  10. [10]
    VADALI, S. R. and KIM, E. S. “Feedback Control of Tethered Satellites Using Lyapunov Stability Theory,” Journal of Guidance, Control and Dynamics, Vol. 14, No. 4, July–Aug. 1991, pp. 729–734.CrossRefGoogle Scholar
  11. [11]
    FUJII, H. and ISHIJIMA, S. “Mission Function Control for Deployment and Retrieval of a Subsatellite,” Journal of Guidance, Control and Dynamics, Vol. 12, No. 2, Mar.–Apr. 1989, pp. 243–247.CrossRefGoogle Scholar
  12. [12]
    BAINUM, P. M. and KUMAR, V. K. “Optimal Control of Shuttle-Tethered-Subsatellite System,” Acta Astronautica, Vol. 7, 1980, pp. 1333–1348.MATHCrossRefGoogle Scholar
  13. [13]
    HUANG, X., HUTAO, C., and PINGYUAN, C. “An Autonomous Optical Navigation and Guidance for Soft Landing on Asteroids,” Acta Astronautica, 2004, pp. 763–771.Google Scholar

Copyright information

© American Astronautical Society, Inc. 2007

Authors and Affiliations

  1. 1.School of AstronauticsBeijing University of Aeronautics and AstronauticsBeijingChina

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