1. For deep space robotic missions, thermoelectric generators are sometimes used to power the spacecraft systems. The power to run these generators often comes from general purpose heat source (GPHS) units which produce heat from the radioactive decay of 238Pu, The 238Pu used in these units is produced by the neutron bombardment of 237Np in special production reactors designed for this purpose. 237Np does not occur naturally, but is available in quantity from reprocessed spent nuclear reactor fuel. The 238 Pu production cycle consists of: n+237Np238Np(2.1day)238Pu(89years)234U Assuming that only 237Np is initially present, determine an expression which yields the timedependent concentration of 238Pu. Also determine an expression which yields the time required to reach a maximum concentration