Bill Gates says SpaceX CEO Elon Musk’s goal of colonizing Mars isn’t a good use of money.

Life-saving vaccines are a better endeavor, the Microsoft co-founder says in an interview with BBC scheduled to air Friday evening, CNBC reports.

In the interview, BBC journalist Amol Rajan asks Gates about SpaceX’s aggressive space rocket investments with the aim of mankind existing on the red planet in the not-too-distant future.

Rajan asks Gates simply, is that is good use of money, to which Gates replies, “Not in my view.”

“It is actually quite expensive to go to Mars,” Gates replies. “You can buy measles vaccines and save lives for a thousand dollars per life saved.”

“It just kinds of grounds you. Don’t go to Mars,” says Gates, whose Bill & Melinda Gates Foundation has invested more than $10 billion to deliver vaccines to the world’s poorest countries.

Asked whether he considers Musk, 2022's world’s richest person, a philanthropist, Gates says he does not think Musk currently has the mindset of a benefactor but that Musk is making a constructive influence on the world.

“Things like Tesla are having a positive impact, even without being a form of philanthropy,” Gates says of Musk’s electric vehicle company. “I think some day he will join the rank of philanthropists using his ingenuity.”

This supports a remark from Gates last year: “I don’t talk about my investments but I think he should be very proud of what he’s done.”

In 2021, Gates told Bloomberg he wished he had “been more on the long side” of Tesla.

However, Gates and Musk have butted heads. In April, Musk asked Gates if he was short-selling Tesla stock.

In 2020, after Gates revealed he selected an electric Porsche Taycan over a Tesla, a Twitter user asked, “I wonder why Bill Gats decided to go with the Taycan instead of Tesla.”

This elicited this tweet from Musk: “My conversations with Gates have been underwhelming tbh [to be honest].”