By Rebecca MarstonBusiness reporter, BBC News
ReutersElon Musk announcing the first private passenger it plans to fly around the moonElon Musk is one of the world's most prominent business figures.
A recent headline-grabber was the announcement of the first paying passenger for his SpaceX venture to fly around the Moon.
He has a number of pioneering achievements to his name, including creating online payment platform PayPal, running electric car maker Tesla, as well as SpaceX.
His innovative and wide-ranging interests include solar energy and artificial intelligence, a high speed travel system involving tubes and magnets, plus he has designs on Mars.
But this year, things seem to have turned sour for the tech entrepreneur.
In August, he startled investors with a tweet saying he was considering taking Tesla private having secured funding.
Two weeks later, he said he had ditched the plan, spurring unhappy investors to launch a lawsuit against him.
Then, in September, he was ordered to step down as Tesla chair and pay a $20m fine, in a deal struck with US regulators over tweets he posted about taking the firm private.
Tesla appointed board member and telecoms executive Robyn Denholm as chair.
SPACEXThe Tesla Roadster in earth orbit, before it headed towards MarsHis erratic behaviour, alongside colourful public outbursts - including dope smoking on a webcast, public whisky drinking (not something they like to see in the buttoned-up US), and accusing one of the divers who rescued the Thai football team marooned in a cave in Thailand of being a paedophile - a claim that has resulted in a lawsuit - has caught the world's attention.
Where did Musk come from?
He was born in Pretoria, South Africa. Growing up he was obsessed with science fiction novels and anything to do with electricity - a perfect platform for his current ventures.
At the age of 17, Musk moved to Canada to study physics and economics, before heading to the US in 1992 to further his studies.
He quit a doctorate programme after just two days and then founded Zip2, an online newspaper platform. He sold that company and went on to set up what became PayPal.
When eBay bought that venture in 2002 for $1.5bn, he pocketed $165m (£125m) aged 31.
Getty ImagesA driver at a Tesla charging station in Fremont, CaliforniaHe got his cash - what then?
While Musk did not found Tesla, his name is the one associated with the company.
After bagging the proceeds from the PayPal sale, Musk poured his fortune into SpaceX, and Tesla, which he led as chairman before becoming chief executive in 2008.
That turned out to be a bad year: SpaceX suffered a third rocket crash and rising costs threatened to ruin Tesla.
But despite the phenomenal technological achievements and exciting innovations, his companies have missed deadline after deadline and recorded huge losses.
Some are now questioning his suitability to lead a listed company like Tesla.
Getty ImagesElon Musk and then-wife Talulah Riley at the White House in 2014His private life is pretty interesting, isn't it?
As well as the dope smoking and Twitter outbursts, he has also been married three times - twice to the same woman.
His first was to Justine Wilson, who appropriately enough was a fantasy writer.
He married Talulah Riley in 2010, but they divorced in 2012.
The following year the couple remarried. In 2014 he filed for, but then withdrew, a second divorce application. Two years later Ms Riley did the same and the couple went their separate ways.
Musk has also been linked with Amber Heard and Cameron Diaz. Robert Downey Jr took inspiration from him to play Tony Stark in Iron Man.
He is said to be a relentless worker. When he founded Zip2, he reportedly worked all day, slept in the office and showered across the road at the YMCA.
Last month, in an emotional interview with the New York Times in which Musk said he worked "120 hour weeks" and sometimes took the sleeping pill Ambien to combat insomnia.
The question now is how long shareholders are willing to put up with Tesla's controversial chief executive.
Shares in the electric car maker have fallen by over a fifth since Musk's shock "funding secured" tweet.
The firm's most recent results showed another record loss.
And some analysts have urged the firm to appoint another senior leader.
One thing which is certain is that Musk is likely to continue to dominate the news headlines for the foreseeable future.
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