Rocket Lab USA, Inc. (RKLB) shares plummeted 10.00% during Thursday's intraday trading session, marking a significant decline for the space technology company.

The sharp drop comes after Congress declined to fund a planned 2031 Mars sample-return mission tied to NASA's Perseverance rover. This decision effectively ends Rocket Lab's opportunity to secure a multibillion-dollar contract, estimated at roughly $4 billion, for ferrying Martian rock, soil, and gas samples back to Earth. The loss of this high-profile deep-space mission represents a setback for the company's long-term growth narrative.

Additional pressure on Rocket Lab and the broader space sector stems from renewed chatter about a potential SpaceX initial public offering, with estimates suggesting a valuation that could exceed $1.5 trillion. This has prompted investors to reshuffle portfolios, with many locking in profits from 2025's rally in space stocks and holding cash in anticipation of a future SpaceX listing. The stock's decline also occurred alongside a broader market downturn on Thursday.