Going to Mars isn't cheap. That's why NASA and the European Space Agency may team up on future trips to Mars in a move that would change NASA's policy toward the planet, the Associated Press reports. The European Space Agency doesn't have the funds to send their new drill-toting rover ExoMars up, and NASA had to slash its spending after delaying the launch of its Mars Science Laboratory until 2011. Although it's hard to unite such disparate missions, the agencies are looking for a way to collaborate. A single rocket may blast the two into space, although it's unclear who would fund the rocket and what kind of joint projects the two agencies might pursue in the future. Critics of the collaboration fear that decreased competition will make the U.S. lose its edge and that future project funding could be held hostage to political concerns.