SAN FRANCISCO — Yury Milner, the Russian investor known for his bets on high-flying social media companies Facebook and Twitter, is raising his sights beyond the stratosphere.

Billionaire Milner led a $52 million investment in satellite maker Planet Labs, the firm said in a statement. Planet Labs said it planned to put a fleet of 28 image-gathering satellites into orbit early next year.

The San Francisco-based company aims to make ultra-efficient satellites that it says can capture and transmit more images at lower costs than traditional satellites. It was founded by three physicists who previously worked at NASA's Ames Research Center in Silicon Valley.

Other new investors joining this round include Industry Ventures, Felicis Ventures, Lux Capital, and Ray Rothrock.

Planet Labs' existing investors include Draper Fisher Jurvetson, Capricorn, O'Reilly Alpha Tech Ventures, Founders Fund, First Round Capital, Innovation Endeavors, Data Collective, and AME Cloud Ventures.

Earlier this week, influential startup program Y Combinator said Milner would no longer automatically invest in each of the companies that participate. Twice a year, Y Combinator admits about 50 young companies for instruction in entrepreneurship and introductions to key players in Silicon Valley.

Yury Milner Invests in Satellite Maker Planet Labs