After Sir Richard Branson’s spaceflight this weekend, the leader of Russia’s main space corporation, Roscosmos, offered some kind words about the achievement on Twitter. Dmitry Rogozin called the flight a “landmark” in terms of technology development and expanding the number of humans able to see Earth from space.

Then Rogozin went a step further, lamenting the fact that Russia’s “billionaire oligarchs” spend their money on yachts and vanity projects rather than the development of space technology and increasing humanity’s knowledge of space.

This is a notable comment from Rogozin, who in the past has been critical of one particular billionaire spending his money developing space technology: SpaceX founder Elon Musk. Among other remarks, Rogozin has said that NASA should not get too cocky about its newfound access to space in case SpaceX’s Crew Dragon vehicle “breaks.” He has also said that SpaceX is “gentle” for getting to work in the balmy conditions of South Texas, while Russian engineers and technicians work in the depths of Siberia during the winter.

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“Go forth and conquer,” actor Kate Winslet says.

SpaceX’s Elon Musk is among the high-profile people celebrating Branson’s preparations for space.