NASA is developing a heavy-lift rocket called the Space Launch System in a bid to visit Pluto's moon Charon or collect samples from outer planets. The first launch of the SLS won't have a second stage, and can set 154,000 pounds into low-Earth orbit. The agency expects to equip the rocket with more powerful boosters and an upper stage that will enable it to send 286,000 pounds to Earth's orbit starting 2022.