NASA’s SLS is making serious progress on the road to being operational–after a successful booster qualification test in March, the second qualification test, planned for spring 2016, will test the booster’s performance for cold motor conditioning will and demonstrate that it meets ballistic requirements.
When completed, two five-segment boosters and four RS-25 main engines will power the SLS on deep space missions, including to an asteroid and ultimately to Mars. The solid rocket boosters — measuring 177 feet long and producing 3.6 million pounds of thrust — operate in parallel with the main engines for the first two minutes of flight. The boosters provide more than 75 percent of the thrust needed for the launch vehicle to escape the gravitational pull of the Earth.