On the existence of a trap state for OSO-type satellites

The possibility of the existence of "trap states" in orbiting-solar-observatory-type satellites which use a single-degree-of-freedom mass-spring-dashpot nutation damper is investigated. It is shown that the spacecraft exhibits a trap state which corresponds to a transverse angular rate of ω
n
, where ω
n
denotes the natural frequency of the specific damping system used. In particular, it is indicated that for
\omega_{10} < \omega_{n}
, where ω
10
is the initial transverse angular rate of the spacecraft, a trap state occurs when the initial displacement z
0
of the damper mass with respect to the spacecraft principal axis exceeds a certain critical value; while for
\omega_{10} > \omega_{n}
, the trap state occurs for any nonzero value of z
0
.