Unheralded stars of SLS program

The historic engine test stand in South Mississippi has been testing engines for
NASA since the 1960s, and it will do the same thing for the next generation of NASA
space rockets...

David Tortorano
February 2018

STENNIS SPACE CENTER, Miss. - It’s a supporting actor in NASA’s high-profile
program to send astronauts to the Moon and beyond, but a close look at the B-2 test
stand shows it’s anything but a minor player in the Space Launch System.

Stennis Space Center (SSC), which has been testing RS-25 engine controllers, is
where the 212-foot core stage will be tested in the first quarter of calendar year
2019. All four RS-25 engines will produce 2 million pounds of thrust and will fire for
just under 500 seconds. It will be the loudest test at SSC since the Saturn V during
the ’70s.

It’s hard to envision just how massive the rocket engine test stands at SSC are until
you get up close. SSC gave that opportunity to social media bloggers and traditional
journalists during a tour and briefing at the test center in mid-February.

The tour included a visit to the B-1/B-2 test stand, which can test rocket engines on
both sides of the structure. The RS-68 engine for the ULA Delta IV is tested on B-1.
An engine was in that stand during the tour. It had been tested the week before and
was scheduled to be removed the following week.

But it was the 360-foot B-2 portion of the stand that was the star of the tour. It was
the stand that tested the five-engine Saturn V, and it was also used to test the three-
engine RS-25 for the Space Shuttle. It was also used to test the common booster
stage for Delta IV before it was mothballed for a time.

Ryan Roberts, B2 stand manager, provided a briefing for the visitors. He admits he
could talk for hours about the stand. But the information he did provide in his 15
minutes showed just how much work goes into the stand, and just how important is its
role.

When it was chosen to test the SLS core, it was necessary to modify the test stand to
handle the huge rocket, the most powerful one ever built. The stand was refurbished
from top to bottom and expanded upward. The core stage is smaller than the stand,
but when it’s put in place above the flame deflector it will top out 14 feet higher than
the B-2 test stand.

The flame deflector, which sits under the engines and redirects the flames, was
repainted and 32,000 of the 5/8-inch diameter holes in the deflector, where cooling
water is ejected, had to be welded shut and re-drilled in the right pattern, Roberts
said. The piping system to bring fuel to the rocket is brand new as well, and portion
of the stand in the middle between B-1 and B-2, the “soft core,” was repainted. One
guy in a bucket painted the NASA “meatball” with a brush, Roberts said.

The rocket engines are cooled by water sprayed during the test as both sound
suppressant and to prevent the flame deflector from getting too hot, providing the
characteristic condensation associated with the test.

The water is supplied by a 66 million gallon reservoir and brought to the test stand
with 10 large pumps and 96-inch diameter pipes. The water flows at the rate of
330,000 gallons per minute, according to Roberts.

In December 2018, the core stage will be brought by covered barge from Michoud
Assembly Facility in New Orleans to SSC, using the canal system built at the test
facility. The stage will be rolled out of the barge then lifted with cranes into position
on the test stand.

The test stand is busy with activity while the rocket is put in place, including the time
the fuel is put into the rocket. But during the test itself, personnel are at a control
center a safe distance from the test stand.

Nobody is in the soft core area of the test stand during a test. “That would be one
heck of a sight,” a media member said.

“For a little while,” chimed in another.

The other star of SLS testing is the A-1 test stand. It’s been used by NASA and SSC
to test the flight controllers, the brain of the RS-25 engines. As of mid-February there
have been two tests of the controllers this year, as well as previous tests last year.
The second test was a full-duration, 365-second certification test.

The second test marked completion of green run testing for all four of the new RS-25
engine flight controllers needed for the second flight of NASA’s SLS rocket. The RS-
25 controllers for the EM-1 flight already are installed on the engines that will be part
of the SLS core stage.

About 40 miles away from SSC at Michoud Assembly Facility in New Orleans,
construction has officially begun on the spaceship that will return astronauts to the
Moon and beyond, the first deep space mission in more than 40 years. Lockheed
Martin technicians and engineers at the Michoud welded the first two components of
the Orion crew module capsule for Exploration Mission-2 (EM-2).

Before that, EM-1, an unscrewed mission, will take off into space for a trip beyond the
moon. That capsule assembled at Michoud is now at Kennedy Space Center, Fla.,
for final work. Michoud will finish the work on the Orion slated for EM-2 in September
and ship that one to Kennedy Space Center, where the Lockheed Martin team will
perform assembly and test of that spacecraft.

Space buffs didn’t have to wait for SLS to get their engines fired up. The SpaceX
Heavy Falcon, the most powerful commercial rocket in the world, roared skyward this
month at Kennedy Space Center, Fla., atop a pillar of smoke in a spectacular launch.

Later, two of the three boosters made vertical landings back at Kennedy, while the
third booster scheduled to land on a drone ship hit the ocean about 100 yards from
the ship.

The 23-story rocket was built with three of the company's proven Falcon 9 rockets,
providing a total of 27 Merlin engines that generated a combined 5 million pounds of
thrust. This rocket is more powerful and can lift more weight than the biggest rockets
offered by either United Launch Alliance or Arianespace.

It was a crucial win for commercial space exploration. A recent report by Bank of
America Merrill Lynch forecast the size of the space industry octupling over the next
three decades to at least $2.7 trillion. And this is good for our region. Some
commercial space companies, including SpaceX, are using engine testing facilities at
Stennis Space Center. For SpaceX, it’s developing its next-generation Raptor
engines.
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