BARCELONA, June 29 (Reuters) - Elon Musk said on Tuesday that total investments in Starlink would reach between $5 billion and $10 billion before the satellite internet venture achieves positive cash flow. Over the lifetime of the project, total investments could run to $20-$30 billion, the Tesla Inc (TSLA.O) CEO told the Mobile World Congress in Barcelona. "It"s a lot, basically," Musk said in a video interview from California.