But his family and friends remember the less serious side.
Old friends on Earth could remember her as she used to be.
"Some good friends who share my views remember only the last two years," he said.
But his friends and colleagues remember him as a man with another mission.
Friends remember asking one another: Was he trying to blow up his career?
Friends from the time remember him as a quiet and shy young man who showed a great deal of interest in music.
One friend remembers that "there was always a little group of boys at his house, doing things."
It's a statistic he would like his family and friends to remember.
But the house had been deserted for years - ever since Greg and his friends could remember.
But these days he is gloomier than his friends can remember.