On Wednesday afternoon in Northern Utah, Northrop Grumman fired up a full-scale test version of the boosters it is building for NASA's Space Launch System rocket. Although engineers were still reviewing 300 channels of data, Charlie Precourt, vice president of propulsion systems at Northrop Grumman, said the test was successful.
Two of these large boosters, each with a mass of 1.6 million pounds, account for 75 percent of the SLS rocket's thrust during the first two minutes of flight. They are composed of five segments of a powderized solid fuel that is ignited upon launch. Northrop has already built 26 of the 30 segments NASA needs for the first three launches of the SLS rocket.
The primary reason for Wednesday's test was that Northrop's supplier of aluminum-based fuel could no longer deliver the product. Therefore, Northrop needed to ensure that a new vendor could provide the solid rocket fuel needed for future launches of the SLS rocket beyond the first three. NASA also used the test to assess some changes to the nozzle design, said Bruce Tiller, manager of the SLS boosters office at NASA’s Marshall Space Flight Center.
With this test, Tiller said NASA remains on track to potentially launch the SLS rocket in late 2021. The boosters for this flight are already being stacked in Florida. The main question is whether the rocket's large core stage, which is set to undergo a critical test firing in Mississippi this fall, will be ready to go.
These solid rocket boosters are a holdover from the space shuttle era, when they powered that vehicle. However, the new boosters have been modernized with improved avionics and made more powerful with the addition of a fifth segment.
The Hatch act
A decade ago, when engineers were planning a new heavy-lift rocket, NASA was told by Congress it had to use solid rocket motors built by ATK, which has since been acquired by Northrop. At the time, Congress was scrambling to keep NASA's major spaceflight contractors employed. With the space shuttle's end looming, US senators cobbled together the basic design of a new rocket, which became known as the SLS vehicle.
A powerful senator from Utah, Orrin Hatch (who actually has nothing to do with the Hatch Act of 1939), ensured that solid rocket motors built and tested in his state would play an important role in the new launch vehicle as part of NASA legislation.
In an October 2010 news release, Sen. Hatch's office said he was "successful in getting language inserted in the bill which details specific payload requirements for a heavy-lift space launch system that, Utah industry experts agree, can only be realistically met through the use of solid rocket motors like the ones manufactured by ATK in northern Utah."
Moreover, the NASA re-authorization legislation further required the space agency to use existing contracts, workforces, and industries from the space shuttle and Ares rockets, including solid rocket motors. This has largely happened. However, NASA has been less successful at meeting another provision of Congress in 2010, developing an "operational capability for the space launch system by the end of 2016."
Because the Space Launch System was designed and built under cost-plus contracts, however, there are no penalties for Northrop, Boeing, and other companies involved with the big rocket. They have continued to be reimbursed for their expenses, plus associated fees, regardless of delays on a development program that has so far cost about $20 billion.
Listing image by NASA TV