Countdown to Deep Space

NASA’s countdown to deep space continued Aug. 13 with the latest test of its Space Launch System (SLS) RS-25 rocket engine at NASA's Stennis Space Center near Bay St. Louis, Mississippi. Operators on the A-1 Test Stand at Stennis conducted a 535-second test to collect engine performance data that will be used in readying the engines for SLS missions to carry humans deeper into space than ever before.
A variety of groups were invited by NASA's Marshall Space Flight Center in Huntsville, Alabama, and Stennis Space Center to view the Aug. 13 test. These included NASA officials; local, state and national elected officials; representatives of major contractors involved in SLS work; social media enthusiasts; local, regional and national media; community leaders from Alabama, Louisiana and Mississippi; NASA Space Flight Awareness honorees; and Stennis employees. Guests were hosted on tours of Stennis facilities, including the Aerojet Rocketdyne engine assembly facility, and also had an opportunity to visit the Pegasus barge that will transport the SLS core stage from NASA's Michoud Assembly Facility in New Orleans to Stennis and Kennedy Space Center in Florida for testing and launch.
An initial 70-metric-ton (77-ton) SLS configuration, referred to as Block 1, will use four Aerojet Rocketdyne RS-25 engines for the core stage, along with two solid rocket boosters, providing more lift to orbit than any current launch vehicle. The SLS will later be configured to provide an unprecedented lift capability of 130 metric tons (143 tons) to enable missions farther into our solar system.
The core stage for the first SLS flight- Exploration Mission-1 - also will be tested at Stennis, which will involve simultaneous firing of the four RS-25 engines just as during an actual launch. NASA is currently testing the RS-25 to adapt it to the new SLS performance requirements and operating environments such as more thrust, higher propellant inlet pressures and lower temperatures, and qualify an all-new engine controller.
Aerojet Rocketdyne of Sacramento, California, is the prime contractor for the RS-25 engine work. The RS-25 engine gives SLS a proven, high performance, affordable main propulsion system for deep space exploration. It is one of the most experienced large rocket engines in the world, with more than a million seconds of ground test and flight operations time. A final test of the current RS-25 developmental engine is planned before the current test series concludes by early September. Testing of RS-25 flight engines will begin later this fall.

[@OmegaMolecule]

Way to go! So excited to see where this engine will take our next generation of explorers!! Thanks for all the hard work every one involved, savor your successful test.

[@TrebleSketch]

I couldn't wait to see the four of these engines going off at the same time ^^

[@MrGreenman447]

I never realized that the first stage would fire for this long! Amazing.

[@RandyArellano]

Congrats on a successful test!

[@brazilobsessedone]

Wow! How cool is that? And loud, steady and strong for our next leap. Could ISS crew see the plume?

[@markfredovich]

+Chris Daley If they had been directly overhead and knew where to look, they probably would have seen the cloud forming. Our crews have photographed Space Shuttle and Soyuz launches from space when timing and lighting were right.

[@germanovich3D]

Good!

[@hectorvelazquezcuriel8114]

Nice, but i have a question, how much steam was produced? could that trigger a storm or a really heavy rain nearby?

[@Elixus]

Hector Velazquez Curiel Yep, they used this same station to test a different rocket years ago, and it was able to produce rain. You can find it on youtube.

[@moonchi1dt]

Elixus It just depends on the dew point on test day. Since this was August we didn't see any rain produced this time, but tests in January and February have been known to productr rain.

[@technicalvault]

Given they actually built the A-3 test stand I wonder if they'll use it for the next series of tests? Would seem petulant not to. The RS-25 can fire at both high altitudes as well as the ground so it would probably give some interesting data.

[@Justin_Martin]

This engine is awesome 🇺🇸👑💕

[@cichyakp]

how much water did you use at this test? ;)

[@PMarkDeBryan]

What is the light blue color that looks like the horizontal hold on the cone?

[@alexisperkins0001]

serious question: if I were to walk towards a firing RS-25 engine, at what distance would my face melt off?

[@Butt0nk3y]

Alexis Perkins Only one way to fine out!

[@markfredovich]

+Alexis Perkins - Well, the exhaust leaving the engine bell is at 6,000 deg F, which is hot enough not just to melt steel, but to boil it. That is why many thousands of gallons of water per minute are being pumped from an 18 million gallon reservoir a short distance away to cool the exhaust channel below the engine. Most of the vapor you see is from the cooling water being instantly converted to steam and then condensing as it leaves the exhaust channel. The engine exhaust itself (also pure water, but in gaseous form) is almost transparent until it moves far enough away to cool and condense. Look at the video where you see the exhaust leaving the engine bell - the flame is bluish white and almost transparent. Also, look at a video of a Shuttle launch. The very bright, white exhaust came from the solid rocket motors; the plumes from the 3 main engines was almost completely clear. I can't tell you how close you could get before your face started to melt; by guess is 50 feet or so. But you would be dead long before then, because you would be killed by the acoustic energy (sound pressure) long before you got close enough to melt - or rather to be instantly vaporized. I was standing 1200 feet from the test stand during this test, and even wearing hearing protection the sound was ear splitting! But at that distance the only heat we felt was from the boiling south-Mississippi sun!

[@alexisperkins0001]

+Mark Bowman Thanks for answering the question, Mark. I have a second, dumber question. Does that mean that acoustic energy is what is creating the thrust? The density of all the pressure against the ground?

[@alexisperkins0001]

+Alexis Perkins And one more question...you said that water is being pumped to cool the exhaust...does that mean there's a pool of water sitting just below the engine bell, or being pumped into the engine itself?

[@MSStateBulldawg83]

Water is being pump into the flame deflector bucket to keep the test stand from melting. There is a huge pond and several very large pump moving water from the holding pond to the test stand during the test.

[@Michael_Michaels]

3:35 Did anyone noticed that greenish blue ring rising on the bell during the test? I wonder what's that!!? EDIT: I found out that it's from the recording...

[@rabidbigdog]

These are babies compared to the F-1 aren't they? ~1670kN thrust compared to ~6000kN for the F-1. You can find F-1 test vids on youtube too.

[@__Paprika]

***** yeah but they are much more efficient. Their Isp is much, much higher

[@drutfurgeson]

at 3:20 Those two guys... Balls of Steel.

[@MikeKillian]

Charlie Henry NASA TV guys, I had a camera setup next to them just out of frame to the left

[@Wizardofgosz]

drutfurgeson Their distance from the test stand is probably understated by the telephoto lens being used.

[@MikeKillian]

Yes this is 1,500 feet away from the stand. Everyone had ear plugs

[@m.moolhuysen5456]

drutfurgeson Does anyone know why the video shows band of mint green and light purple color slowly shifting over the engine nozzle bell? I'm curious what causes this artifact.

[@markfredovich]

+drutfurgeson That's an illusion - telephoto lens compression. They were about 1100 feet away from the test stand, much farther than it looks, and just 100 feet in front of me.

[@Wizardofgosz]

What's up with the shirts the engineers are wearing? Is it some sort of tradition? It seems unlikely that they would have all chosen such.... questionable fashion to go to work in. :-)

[@m.moolhuysen5456]

Richard Wielgosz Maybe they feel that their wear is just practical, and that it's not very practical to obey the ever shifting current fashions.

[@moonchi1dt]

Richard Wielgosz It is a tradition. On test day all the engineers where Hawaiian shirts. On this particular day NASA Stennis employees were enjoying a "Spirit" week leading up to the test. On test day it was Hawaiian shirt day, so you may see people in the crowd also wearing Hawaiian shirts.

[@Wizardofgosz]

Theresa Smith I had a feeling. Someone needs a talking to, however. They let Paisley slip in. :-)

[@crash6674]

News flash 40 year old design works, way to push the bounds

[@youtubesucks494]

crash6674 *boundaries

[@محمدرجب-ه9ف5ف]

العمل والنشاطات العمل والنشاطات العمل والنشاطات العمل والنشاطات العمل والنشاطات والمذيد والمذيد والمذيد والمذيد والمذيد والمذيد من السحاب