Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
우주선이 탈출속도를 초과해야 지구의 중력을 벗어날 수 있습니다.ujuseon-i talchulsokdo-reul chogahaeya jigu-ui jungnyeok-eul beoseonal su itsseumnida.The spacecraft must exceed escape velocity to break free from Earth's gravity.