Elon Musk and Jeff Bezos have been sniping at each other for months over multi-million dollar contracts and whose space company is the best - and Bill Gates has had enough.
The Microsoft founder took aim at the billionaires during an interview with James Corden, saying "Space? We have a lot to do here on Earth," when asked about the SpaceX and Blue Origin founders.
"I don't know - I've become obsessed with things like Malaria and HIV and getting rid of those diseases, and I probably bore people at cocktail parties talking about diseases," he said.
Corden had previously thanked Gates for being "the one billionaire who's not trying to escape planet Earth on a spaceship right now".
While Musk's stated long-term goal for SpaceX is the colonisation of Mars in order to ensure the survival of the human species, others have also raised questions about so much money being spent on something that can be seen as frivolous.
United Nations Secretary-General Antonio Guterres told world leaders at the UN General Assembly in September that "billionaires joyriding to space while millions go hungry on Earth" was another demonstration of the gap between the poor and the uber wealthy.
He put them in the same basket as corruption, hopelessness and the curtailing of personal freedoms, saying "parents see a future for their children that looks even bleaker than the struggles of today".
Prior to Bezos's trip to space in July, the charity organisation Oxfam, also blasted the expenditure as "human folly" and said it shouldn't be seen as a human achievement.
"Jeff Bezos pays next to no US income tax but can spend US$7.5 billion on his own aerospace adventure," Deepak Xavier, Oxfam International's global head of inequality campaign, said.
"Billionaires burning into space, away from a world of pandemic, climate change and starvation. Eleven people are likely now dying of hunger each minute."
In the past year up to 20 million more people have fallen into hunger, with a six-fold increase in famine-like conditions, the organisation said.
But there has been some altruism in among the billions spent sending the rich few to space.
SpaceX's Inspiration4 mission in September, which included the first ever all-civilian crew to orbit the Earth, raised more than US$200 million for St Jude Children's Research Hospital.
