NASA has fired the starting gun on one of the biggest contracts in commercial spaceflight, releasing a draft solicitation on 6 July inviting private firms to design, build, and operate a space station to replace the ageing International Space Station (ISS). The prize is a foothold in a market analysts expect to grow from roughly $4.2B (£3.1B) today to more than $20B (£15B) by the mid-2030s, with the winners becoming the landlords of low Earth or…