There is one more reason for fans of Elon Musk to believe everything the man touches turns to gold. SpaceX, the rocket maker founded by the technology entrepreneur and best known for wanting to colonize Mars, is now valued at an estimated $21.5 billion, according to Equidate, a website that provides post-money valuation data on privately held companies. By comparison, privately held Uber was valued at $69.8 billion in a funding round in February, according to the site.

A new filing shows the company has raised another $100 million in an extension to its latest funding round, bringing the total amount raised with the sale of shares this year to $449 million. SpaceX’s valuation jumped by about 50% in July after a $349-million dollar round.

The company, which makes the majority of its money from sending commercial satellites into space, declined to comment. (See also: How SpaceX Reinvented the Rocket Launch Industry.)

In 2015, Fidelity and Google (GOOGL) pumped $1 billion into the company, bringing the rocket maker’s valuation up to around $11 billion.

The New York Times, citing data from research firm CB Insights, added that the near doubling of SpaceX’s valuation since then means it is now one of seven venture-capital backed companies worth in excess of $20 billion.

Four of these six other companies are based in the United States. Topping the list is ride-hailing giant Uber. Hospitality service AirBnb, We Work, a provider of shared workspaces, and analytics firm Palantir also made the cut.

The two other privately held companies worth more than $20 billion are ride-hailing specialist Didi Chuxing and consumer electronics maker Xiaomi, both of which are based in China.

SpaceX has encountered several setbacks since first being introduced to the world by Musk in 2002. The company initially struggled to meet many of its lofty promises and was then shrouded in further controversy last September when one of its Falcon 9 rockets caught fire and exploded while refueling on its launch pad.

Since then SpaceX has managed to restore its reputation, emerging as a cost-effective provider of trips to the International Space Station. The company has devised ways to reuse parts of its rockets, making launches much cheaper, and has already executed 10 successful take-offs so far this year. (See also: SpaceX Makes History By Landing Reusable Rocket Again.)

According to CNN Money, Falcon 9 launches have a sticker price of $62 million, making them at least $38 million cheaper than competitors.