A person who has a weight of 159 ​pound-force ​[lbf​] on Earth is travelling to Mars in a spacecraft. As long as the engines on the spacecraft are not​ operating, the person is essentially weightless during the voyage. During a course​ correction, the spacecraft undergoes an acceleration of 0.74 g. The term​ "g" is the​ Earth-normal gravity, so 1 g is 9.8 meters per second squared ​[m/s2​]. This acceleration makes it feel like there is gravity in the​ spacecraft, and the person will have a perceived weight during the acceleration​ period, rather than feeling weightless. What is the​ person's mass, in units of kilograms​ [kg], in the spacecraft while travelling to Mars when the engines are not​ running?