Answer
Astronaut moves with a speed of 0.083 m/s in the opposite direction.
Work Step by Step
According to the law of conservation of linear momentum,
Final momentum= Initial momentum
That is, $m_{a}v_{a}+m_{h}v_{h}=0$
$\implies v_{a}=\frac{-m_{h}v_{h}}{m_{a}}=\frac{-0.50kg\times10m/s}{60kg}=-0.083\,m/s$
The negative sign indicates that the astronaut is moving in the opposite direction.
