Al Jazeera America will cease operations at the end of April, the final chapter in a tale of failed ambition by the government of Qatar to establish a TV-news beachhead in the U.S.

The decision was “driven by the fact that our business model is simply not sustainable in light of the economic challenges in the US media marketplace,” Al Anstey, the network’s CEO, said in an email to staff Wednesday. The network will shut down as of April 30, he said, and the broader Al Jazeera newsgathering operation, which has more strength overseas, will be available via mobile and digital in the United States in expanded fashion.

“I know the closure of AJAM will be a massive disappointment for everyone here who has worked tirelessly for our long-term future,” Anstey said in the memo. The executive did not respond immediately to a text message seeking additional comment.

The closure marks the last gasp of an aggressive foray into U.S. TV journalism. Al Jazeera in 2013 paid a whopping $500 million for Current, the naescent cable-news outlet owned in part by former U.S. Vice President Al Gore, and launched its U.S. outlet quickly in August of that year with respected talent like Kate O’Brian, a top executive at ABC News, and Ali Velshi, a popular correspondent on CNN. Al Jazeera executives vowed to stay above the usual fray and din of cable-news programming, bearing down more seriously on the news of the day without resorting to the common technique of having talking-head guests shout at each other.

Yet the network ran into headwinds from the get-go. Ratings were perennially low. Many advertisers shunned the outlet, choosing instead to run low-cost direct response or so-called “programmatic” advertising on its air. There was some thought that concerns about Al Jazeera’s Qatar backing may have turned off Madison Avenue.

And the network always seemed to be in the midst of tremendous flux. Under a previous chief, Ehab Al Shihabi, Al Jazeera America’s schedule was tinkered with constantly. Some freelancers and staffers were laid off. Al Jazeera faced questions about a wrongful-termination lawsuit as well as defections of senior executives.

The network’s new CEO, Anstey, offered a rosier picture in November, saying that the fast pace of launch had contributed to demoralization of the staff. Anstey vowed to set things right and continue on the network’s mission of presenting a more serious level of news. ”I think we should not be sitting here and be too optimistic,” he told Variety in November. “It’s going to take time to build viewership.” He also said the network’s parent had a “long term commitment” to maintaining its U.S. operations  – something that turned out to be inaccurate.

In recent days, Al Jazeera America did make a mark. It aired a report earlier this month linking football great Peyton Manning to performance-enhancing drugs. Manning denied the allegations.