A regulatory filing made yesterday revealed that SpaceX, the rocket company of Tesla boss Elon Musk, has raised $337.4 million in new funding. The investment round filing followed internal memos that warned staff the future of the ambitious company was heavily reliant on being able to attract fresh funding into the capital intensive business.

SpaceX has an impressive roll-call of investors that include the funds giant Fidelity Investments and Google-owner Alphabet. The space exploration and rocket launch start-up’s most recent valuation was $100 billion when it raised money from a sale of equity in October. $1.2 billion in equity financing was also raised in April.

SpaceX makes money by sending rockets up into near space carrying payloads for customers and recently won a $2.9 billion contract from NASA to run its Human Landing System program which will return astronauts to the surface of the moon. It has also already launched several cargo payloads for NASA, carrying supplies to the International Space Station.

The company is also building its own satellite-based commercial internet service, Starlink, which is designed to bring high-speed connections to remote regions anywhere in the world. It has already launched almost 2000 satellites of a network planned to consist of tens of thousands more.

Its competitors include Blue Origin, owned by Amazon owner Jeff Bezos, and Sir Richard Branson’s Virgin Galactic. All three companies have this year launched their first missions carrying civilian ‘space tourists’. Morgan Stanley estimates the space economy could be worth as much as $1 trillion by 2040.

SpaceX’s Starlink constellation has recently attracted criticism from China, which says satellites launched by the company have come dangerously close to crashing into its under-construction space station twice in the past few months. Chinese diplomats complained to the UN committee on the peaceful use of outer space, saying the station was forced to take “evasive manoeuvers” to avoid a collision. Musk has dismissed the argument Starlink’s constellation is taking up to much of the Earth’s near orbit, saying there is room for “tens of billions” of spacecraft.

Musk responded by telling the Financial Times:

“Space is just extremely enormous and satellites are very tiny. This is not some situation where we’re effectively blocking others in any way. We’ve not blocked anyone from doing anything, nor do we expect to.”