UnScramble this Word: n t i s c e c o?

Questions

In 1955 Olga ---------- (in Russia), gymnast, born. ?

In 1966 Janet---------- , singer, Michael's sister, born. ?

In 1969---------- , Venus landing. First successful landing on another planet. ?

In 1970 Gabriela---------- , tennis professional, raqueteer, born. ?

In 1975 Japanese Junko ---------- became first woman to reach Mt Everest's summit. ?