Rocket Lab is still unprofitable, but has the cash it needs to make a run at profitability over the next two years.Investors weren't too impressed with Rocket Lab's (RKLB 1.26%) first-quarter earnings report Monday, selling shares of the space stock down 2% despite Rocket Lab reporting 69% sales growth in Q1 -- and predicting up to 77% growth in Q2!But one Wall Street analyst firm begs to differ.On Tuesday, investment bank Citigroup repeated its opinion that Rocket Lab stock is a buy. The banker did nudge i ...