Commercial development of space technology depends on an ability to see return on investment. Without it, development is restricted to state-sponsored space programs or private firms contracting from the government.
One of the commonly-considered ways to incentivise private-sector investment in space is to allow companies to harvest resources found commonly in space that are rare or hard to extract on Earth. Rare metals and minerals as well as water (an extremely valuable commodity in space) can be found in near-Earth asteroids and could in theory be towed into Earth orbit and mined. However, the significant investment required to do so requires a solid legal foundation for rights over the mined resources. By signing this bill, the US has declared that private firms are entitled to any abiotic resources they can get their hands on - very much a "wild west" situation.
Currently international treaties forbid the ownership of parts of space by nations, and declare governments responsible for the activities of their non-governmental organisations (which in theory could cover businesses seeking to harvest resources). Whether the new US law is compatible with these treaties remains to be seen; what is certain is that interested nations may well conveniently ignore international law in order to get a head start on what could be an extremely lucrative industry.
In a sense this is a setback for scientific exploration of space - opening up space to property rights claims potentially means damage to or contamination of scientifically-valuable sites, restrictions on scientific activity, and the spectre of international law being ignored in favour of military activity in space. On the other hand, significant investment in space technology by commercial partners can only help accelerate space exploration efforts, bring in new data, and open up new horizons in a very literal sense. As always, politics is likely to be the deciding factor.
Planetary Resources, the asteroid mining company, applauds President Obama who signed the U.S. Commercial Space Launch Competitiveness Act (H.R. 2262) into law. This law recognizes the right of U.S. citizens to own asteroid resources they obtain and encourages the commercial exploration and utilization of resources from asteroids.