Nasa's pioneering black women

In recent years, black women's contributions to the space race have started to come to light.

Many were recruited as "computers", meaning that they carried out complex mathematical calculations by hand, before machines were invented that could do the job.

Christine Darden started her career in the computer pool, helping the engineers work out the trajectories needed to bring the Apollo Capsule back to Earth.

Witness History: The stories of our times told by the people who were there.