When SpaceX goes public on Friday with what is expected to be a record-setting initial public offering, it will cap two decades of founder and CEO Elon Musk’s ambition to transform rocketry, satellite communications and humanity’s reach into space.

Each step of the way, there has been a guiding hand largely out of view: the company’s president, Gwynne Shotwell, who has spent 24 years focused on building and selling SpaceX through her engineering expertise and dealmaking ?instincts. Along the way, colleagues say Shotwell, 62, developed a more elusive skill: managing Musk, himself.

She frames her job in simple terms, telling Time magazine earlier this year ?that ?she wants to be “helpful to Elon” and “add value.” But SpaceX veterans and industry observers see her as a key figure at ?the space industry leader, whose rise has made her one of the world’s most powerful female executives.