Shares surged as much as 30% when trading began today, but the average investor may want to keep their feet on Earth.

When SpaceX makes its debut on the U.S. stock market, it wants smaller-pocketed, mom-and-pop investors to play a big role in what may be the biggest IPO ever.

Most of the value in SpaceX's IPO is effectively a call option on the company's ambitious space data center plans.

Hype and hope collide in the biggest IPO in history