Cake, gifts and a low-key family celebration may be how many senior citizens picture their 70th birthday.

But NASA's oldest serving astronaut Don Pettit became a septuagenarian while hurtling towards the Earth in a spacecraft to wrap up a seven-month mission aboard the International Space Station (ISS).

A Soyuz capsule carrying the American and two Russian cosmonauts landed in Kazakhstan on Sunday, the day of Pettit's milestone birthday.