Adaptive attitude control for long-life space vehicles

A general structure of the kinematic equations for attitude evolution of a spacecraft (SC) (coordinate system associated with a spacecraft (SCS)) relative to the reference coordinate system (RCS) is proposed. It is assumed that the origins of the coordinate systems coincide and are located at an arbitrary point of the spacecraft. Each of the coordinate systems rotates at an arbitrary absolute angular velocity (relative to the inertial space) specified by the projections on their axes. Attitude parameters can be the Euler–Krylov angles, Rodrigues–Hamilton parameters, and modified Rodrigues parameters. It is shown that the well-known representations of the attitude evolution equations of the SCS relative to the RCS using the Rodrigues-Hamilton parameters (components of normalized quaternions) can be simply obtained from the solution of the Erugin problem of finding the entire set of differential equations with a given integral of motion. The advantages and disadvantages of use for each of the specified attitude parameters are considered. A method of attitude control synthesis is proposed which is common for all these equations and based on the decomposition of the original problem into kinematic and dynamic ones and the use of well-known generalizations of the direct Lyapunov method for their solution. The property of structural roughness according to Andronov–Pontryagin [27–29] of the obtained algorithm is illustrated with the help of computer simulation. Particularly, a specific example illustrates the possibility for even a structurally simplified algorithm of stabilizing a specified constant spacecraft attitude to track the program of its change with sufficient accuracy. The tracking task is typical for the control of spacecraft docking, spacecraft de-orbiting, and performing route surveys of the Earth's surface.

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Miniature Long-Life Space-Qualified Pulse Tube Cryocooler

10.4271/941622 ◽

1994 ◽

Author(s):

E. Tward ◽

C.K. Chan ◽

J. Raab ◽

R. Orsini

Keyword(s):

Pulse Tube ◽

Life Space ◽

Pulse Tube Cryocooler ◽

Long Life

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Micro (Cost) Technologies for Spacecraft Control and Command: An Example, Balloon-Borne Stabilised Gondolas

CANEUS2006: MNT for Aerospace Applications ◽

10.1115/caneus2006-11014 ◽

2006 ◽

Author(s):

Andre´ Laurens

Keyword(s):

Attitude Control ◽

Low Cost ◽

Distributed Applications ◽

System Level ◽

Space Vehicles ◽

Design Development ◽

Development Costs ◽

Open Standard ◽

Long Time ◽

Flexible Architectures

Balloons are long-time known space vehicles for science missions and technology in-flight experiments, with instruments that need out-of-atmosphere or in-situ measurements, thus being complementary to the satellite. They carry micro (few hundred grams) to mega (few tons) payloads, but all of them require micro cost, short development, multiple flights. Among the big ones, CNES stabilised gondolas are versatile space platforms used to fly science instruments mainly coming for aeronomy and astrophysics communities, and requiring stabilisation and pointing capabilities, analogous to satellite attitude control subsystems. For them, cost and development constraints cannot be met without highly flexible architectures and off-the-shelf components. In order to increase gondola flexibility to new missions (or adaptability to mission evolutions), new hardware and software solution have been studied for control & command, including stabilisation and pointing functions. Promoted technologies are those of industrial computers, ground networks, free software and, over all, Ada language, for they are open, standard, powerful, low-cost and long-lasting solutions. After a brief description of domain-oriented characteristics of the stabilised gondola control & command, this paper introduces the various technologies and main design principles proposed to meet system-level goals. Then focus is put on on-board architectures: full Ada95 real-time distributed applications on an Ethernet-IP LAN of industrial PCs running Linux, and describes the prototyping work and preliminary development done to ensure feasibility. The paper then discusses the applicability of such solutions to global, ground-to-board, distributed control & command applications, through an IP-based telemetry & telecommand link, such as the one under development in CNES for balloon systems. As a conclusion, this paper shows how adoption of these technologies for other space programs such as satellite platforms and payloads may change design, development costs, duration and organisation, as well as it may open new ways in ground-to-board communication and spacecraft operation.

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