(Reuters) - Billionaire Elon Musk’s SpaceX has raised about $850 million in equity financing, the private rocket launch service said in a regulatory filing on Tuesday. The private space company had raised $1.9 billion in August in its largest single fundraising round, according to financial software and data provider PitchBook. The latest round reportedly lifted the valuation of the company whose investors include Alphabet Inc and Fidelity Investments to about $74 billion. Earlier this month, a prototype of SpaceX’s Starship rocket exploded during a landing attempt after a high-altitude test launch. The SN9 prototype was a test model of the heavy-lift rocket being developed by the company to carry humans and 100 tons of cargo on future missions to the moon and Mars.