In today’s Bulldog wrapup of technology news:

  • A successful SpaceX launch
  • Tesla shares drop after pledge to boost production
  • Space Invaders, Grand Theft Auto III make video game Hall of Fame
  • The man who claimed to have invented bitcoin backtracks

The details:

  • SpaceX launch success

For the second month in a row, the aerospace upstart SpaceX landed a rocket on an ocean platform early Friday, this time following the successful launch of a Japanese communications satellite.

A live web broadcast showed the first-stage booster touching down vertically in the pre-dawn darkness atop a barge in the Atlantic, just off the Florida coast. The same thing occurred April 8 during a space station supply run for NASA. That was the first successful landing at sea for SpaceX, which expects to start reusing its unmanned Falcon rockets as early as this summer to save money and lower costs.

Because of the high altitude needed for this mission, SpaceX did not expect a successful landing. But it was wrong. As the launch commentator happily declared, “The Falcon has landed.”

SpaceX founder and chief executive Elon Musk was even more exuberant. “Woohoo!!” he exclaimed in bold letters via Twitter.

“May need to increase size of rocket storage hangar,” he added in a tweet.

Musk said this was a three-engine burn for the booster’s return, “so triple deceleration from the last flight.” Before liftoff from Cape Canaveral, Florida, he put the chances of a successful touchdown at “maybe even” because the rocket was coming in faster and hotter than last time.

  • Tesla Motors is staring down the naysayers

Tesla CEO Elon Musk’s surprised investors Wednesday with a promise to make 500,000 cars per year by 2018, two years ahead of plan — a brash projection given that Tesla has missed smaller production targets in the past.

Auto industry analysts balked. Many doubt that Tesla has the cash, plant capacity or manufacturing expertise to pull off those numbers.

“This is beyond challenging,” said Jeff Schuster, senior vice president for forecasting at the consulting firm LMC Automotive. “There are so many things that would have to be lined up in a very short amount of time for that to happen.”

Tesla’s shares dropped 5 percent to $212.02 Thursday.

But the auto industry and some on Wall Street have been wrong before about 13-year-old Tesla. It has sold more than 110,000 vehicles worldwide even without a traditional dealer network. The company has never made a full-year profit but its market value is more than half that of General Motors Co. U.S. sales of Tesla’s Model S luxury sedan jumped 51 percent last year, even as luxury competitors from Mercedes and Audi saw big sales declines. It doesn’t advertise, but drew lines hundreds deep in March when it started taking deposits for its newest car, the lower-cost Model 3.

Tesla has plenty of believers. Among them is Andrea James, a longtime Tesla analyst with Dougherty and Co. She announced Wednesday she was resigning and said she can’t wait to buy Tesla shares.

“Does Tesla have a technology lead that is real? Can Tesla build it? Will people come? Yes, yes and yes,” James said.

  • ‘Space Invaders,’ ‘Grand Theft Auto III’ hall of fame games

A video game that allowed players to zap marching aliens with dot lasers and another that gave them flamethrowers and put them in the driver’s seat in a violent 3-D world are among six games inducted into the World Video Game Hall of Fame.

“Space Invaders” and “Grand Theft Auto III,” along with “The Oregon Trail,” ”Sonic the Hedgehog,” ”The Legend of Zelda” and “The Sims,” were honored Thursday for their influence on gaming and pop culture at the hall inside The Strong museum in Rochester.

“Space Invaders” wasn’t the first shooter game when it was introduced in Japan in 1978, but it spurred many imitators and a craze for arcade games, said Jeremy Saucier, assistant director of The Strong’s International Center for the History of ElectronicGames.

A virtual universe away, “Grand Theft Auto III” armed players with flamethrowers and assault rifles.

“By providing players with a license to do virtually anything they wanted to do on foot or behind the wheel, ‘Grand Theft Auto III’ renewed debates about the role of games and violence in society while it signaled video games aren’t just for kids,” Saucier said.

The title sold 14.5 million copies by 2008.

The hall of fame inductees were chosen from among 15 finalists culled from thousands of nominations from around the world. Contenders that missed the final cut were: “John Madden Football,” ”Elite,” ”Final Fantasy,” ”Minecraft,” ”Nurburgring,” ”Pokemon Red and Green,” ”Sid Meier’s Civilization,” ”Street Fighter II” and “Tomb Raider.”

The Strong, which also houses the National Toy Hall of Fame, opened the World VideoGame Hall of Fame last year to recognize electronic games of all types — arcade, console, computer, hand-held and mobile. To get in, games must have had sustained popularity and influenced the video game industry or society.

  • Bitcoin’s self-proclaimed founder backtracks

The man who claimed to be the mysterious founder of bitcoin appears to be stepping back into the shadows, leaving numerous questions in his wake.

Three days after Australian entrepreneur Craig Wright came forward as “Satoshi Nakamoto,” the unknown creator of the digital currency bitcoin, he has backtracked in a dramatic fashion. He wrote in a blog post that he does not “have the courage” to publish additional proof, as he promised Wednesday, that he is the elusive creator of the Internet currency.

Wright’s initial claims drew widespread skepticism. He said on Wednesday that he would provide verifiable documentation and take additional steps to prove his identity. Instead, he scrubbed his blog clean of past entries and posted a short statement titled “I’m Sorry.”

Wright didn’t explicitly renounce his claim to have created bitcoin. He merely wrote Thursday that he thought he could “put the years of anonymity and hiding behind me.” But as this week’s events unfolded, he wrote, “I am not strong enough for this.”

“I can only say I’m sorry,” he wrote at the end of the post. “And goodbye.”

The search for Nakamoto has been a parlor game for journalists and online sleuths since he disappeared from online forums in late 2010. Wright claimed to be Nakamoto in interviews with the Economist, BBC, GQ and a few bitcoin insiders in stories published Monday. He bolstered it with technical demonstrations that two of those insiders vouched for, but failed to repeat those proofs in ways that would allow anyone else to verify them.

Skeptics reacted harshly to the public proof Wright did offer. For instance, he purported to sign a passage from Jean-Paul Sartre with one of Nakamoto’s private encryption keys. Experts argued he hadn’t done that at all, and instead had merely republished a snippet from a historical bitcoin transaction signed by the original Nakamoto.