NASA spent most of its time in March and April to accelerate the development of the Space Launch System rocket, and was looking for ways to launch the big booster in 2020 rather than continuing delay it. Options included skipping a "green run" test of the core phase of the rocket ̵
NASA was preparing for this test. This is a good decade, and the agency said the company spent about $ 230 million on renovating and modifying the B-2 test stand at the Stennis Space Center in Mississippi for this purpose output. These modifications included special equipment required for the SLS rocket's Green Run test and for future upper-stage testing.
During the test, the rocket is jammed, and its shot marks an important step to confirm that the rocket works as expected during an actual launch. However, transporting the core stage to the test rig, installing, testing, deploying, and re-moving the core stage would probably take six to nine months. By skipping the test, NASA could have saved a lot of time by developing a rocket that is already more than two years late, which may allow the Agency to hold the rocket at its most recent launch date in mid-2020.
"Urgency Is Our Mantra"
In a memo shared with senior agency managers earlier this week, NASA's human space chief William Gerstenmaier said the green test will continue. He also acknowledged that the first test flight of the rocket, Exploration Mission-1 (EM-1), would probably be postponed beyond 2020.
"Ultimately, it was my recommendation to the agency that we maintain the plan with the plan we have been doing for many years," wrote Gerstenmaier in the April 22 note that Ars received. "Although we are not sure at the start, in my opinion this is the best approach to a successful EM-1 test and NASA is on its way to an EM-2 crew in 2022 and a Lunar Surface mission in 2024
Among those who received a copy of the memo was Jody Singer, director of the Marshall Space Flight Center, which manages the development of the SLS rocket, and in announcing his decision, Gerstenmaier also expressed the urgency.  "However, we need to have a higher level of urgency in realizing EM-1 and beyond," wrote Gerstenmaier. "I urge the entire NASA / industry community to work diligently towards the earliest possible launch of EM-1 Find out how we can be more efficient, and continue to pay attention to details, to make NASA [to have] a successful EM-1. "He concluded his letter with the words," Urgency is our mantra and we need to do it right. "
The agency did not publicly comment on the memo, and on Thursday a spokeswoman for Ars on the Green Run decision said," We are still judging, and no final decisions have yet been made. "
In recent weeks, the future of the SLS rocket has been a hot topic for the agency. The Trump administration wants to accelerate people's return to the moon by 2024, and NASA Administrator Jim Bridenstine said the SLS must play a key role and further delays in launch would jeopardize the date of 2024, at least when the lunar mission relies on SLS's performance.
The Green Run question Tests also appeared on NASA's NASA Aerospace Safety Advisory on Thursday, where members of NASA recommended that the test be run to test the panel e to ensure safety of the rocket. NASA's current plan envisages launching only a single test flight of the SLS rocket before the crew is placed on the EM-2 mission intended to fly a crew into lunar orbit.
"There is no other test approach the NASA rocket will take to large scale critical operating data of the integrated propulsion system required for safe operation," said jury chair Patricia Sanders on the Green Run test , "Short engine firing at the launch pad will not achieve understanding of operating margins and could have serious consequences."