Nature: The Mars Science Laboratory (MSL) is due to blast off in late 2011, two years later than originally planned. But so are several other missions that will require the use of an Atlas V rocket and the launchpad in Cape Canaveral, Florida.Squeezing MSL into the schedule could require buying a more powerful rocket, reworking the lander’s heat shield for faster entry speeds, and hiring more workers to cut the time between launches. All this could add US$50 million to the cost of a mission whose budget hasalready risen from $1.6 billion to more than $2.2 billion.