This article is more than 2 years old.

February 17, 2017 This article is more than 2 years old.

Elon Musk is a tough cookie to impress. At job interviews, the co-founder of Tesla and SpaceX is known to ask notoriously difficult questions. And if and when he’s hired someone, he can apparently be an incredibly demanding boss.

Even on Twitter, where the billionaire has been pottering around since June 2009, he doesn’t seem to have been blown away by much. During the last seven-and-a-half years on the platform, Musk has used the words “impress,” “impressed” or “impressive” only once.

Musk’s momentous choice of words was prompted by a question from Twitter user @Floydilicious after ISRO, India’s space agency, managed to launch a record 104 satellites atop a single rocket on Feb. 15.

The world’s 21st richest man, who wants to colonise Mars, had even more praise for India’s space programme.

(And then he went back to tweeting about “dad jokes.”)

Musk’s SpaceX and ISRO are competitors of sorts in the business of commercial satellite launches. The former has changed the market’s pricing dynamic with the Falcon 9 launch vehicle, which starts at about $62 million per launch, while ISRO’s Polar Satellite Launch Vehicle (PSLV) costs about $15 million per launch but can carry a smaller payload compared to SpaceX’s rockets.

In recent years, ISRO’s frugal technology, including pulling off the Mars Orbiter Mission for only $74 million, has brought it much acknowledgement and acclaim. Now, even Musk is paying attention.