PARIS — Established satellite-fleet operators Inmarsat, Intelsat and EchoStar have signaled interest in bidding for the 57 percent stake of satellite broadband provider Hughes Communications that is being put up for sale by its owner, private-equity investor Apollo, industry officials said.

Regardless of whether these companies will pursue their interest into an auction likely to feature competing bids by several private-equity investors, even an initial interest by them suggests how far Ka-band satellite broadband has come in terms of market acceptance.

Germantown, Md.-based Hughes’ principal business is providing satellite broadband to corporate, government and consumer customers. In the United States, it operates the fast-growing HughesNet consumer service, which is gradually being moved onto Hughes’ Spaceway 3 Ka-band satellite. A much larger spacecraft, called Jupiter, is scheduled for launch in early 2012.

Hughes also has purchased Ka-band capacity from London-based Avanti Communications, on that company’s Hylas 1 satellite over Europe, and is a likely contender for work on Australia’s National Broadband Network, which plans two Ka-band broadband satellites.

Englewood, Colo.-based EchoStar was a pioneer in consumer satellite broadband in the United States and is looking for growth opportunities. London-based Inmarsat, a veteran provider of mobile satellite services, in 2010 ordered three Ka-band satellites from Boeing to provide a global network for corporate and government users.

Luxembourg- and Washington-based Intelsat up to now has shown little interest in Ka-band, having divested its shares of consumer-broadband provider WildBlue Communications when that company was purchased by ViaSat Inc. of Carlsbad, Calif. ViaSat and Hughes are now direct competitors in both the hardware and services pieces of the consumer-broadband business.

EchoStar, Inmarsat and Intelsat officials declined to comment on the Hughes sale.