Nastasha Romanenko is a Ukranian weapons expert who helps Snake throughout MGS1 (although the player never needs to contact her at any time). She gives advice to Snake about nuclear weapons.
Her frequency was 141.52.
She is/was married to Richard Ames
 In the Darkness of Shadow Moses: The Unofficial Truth
Nastasha wrote a book about what happened at Shadow Moses. Players can unlock this book by (on Metal Gear Solid 2: Sons of Liberty going into "SPECIAL", choosing "Previous Story", and then scrolling through the newspaper article.