Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Attitude Control of a 2U Cubesat by Magnetic and Air Drag Torques   This paper describes the development of a magnetic attitude control subsystem
for a 2U cubesat. Due to the presence of gravity gradient torques, the
satellite dynamics are open-loop unstable near the desired pointing
configuration. Nevertheless the linearized time-varying system is completely
controllable, under easily verifiable conditions, and the system's disturbance
rejection capabilities can be enhanced by adding air drag panels exemplifying a
beneficial interplay between hardware design and control. In the paper,
conditions for the complete controllability for the case of a magnetically
controlled satellite with passive air drag panels are developed, and simulation
case studies with the LQR and MPC control designs applied in combination with a
nonlinear time-varying input transformation are presented to demonstrate the
ability of the closed-loop system to satisfy mission objectives despite
disturbance torques.

3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph