NASA Successfully Test Fires J-2X Engine. 119
tetrahedrassface writes "NASA successfully test fired the J-2X engine Wednesday for 500 seconds at Stennis Space Center. The J2-X is derived from the J2 engine from the Apollo Era, and will power the upper stage of the SLS. From the article: 'We have 500 seconds of good data, and the first look is that everything went great. The J-2X engine team and the SLS program as a whole are extremely happy that we accomplished a good, safe and successful test today,' said Mike Kynard, Space Launch System Engines Element Manager at NASA's Marshall Space Flight Center in Huntsville, Ala. 'This engine test firing gives us critical data to move forward in the engine's development.'"
Re:at the risk of sounding like a heartless bastar (Score:3, Informative)
so they rebuilt 1960's technology and it worked...so lets find those old engineers who designed stuff that actually worked and pat them on the back.
If I remember correctly, the J-2X is a substantially improved version of the engine with a few hundred changes over the original J-2, but, yeah, this story would be more interesting if SLS was ever going to fly.
Liquid hydrogen and liquid oxygen as fuel... (Score:3, Informative)
Re:Liquid hydrogen and liquid oxygen as fuel... (Score:5, Informative)
The first stage engines F-1 were kerosene and oxygen. The J-2 wereon the second and third stage and were hydrogen and oxygen.
Re:Liquid hydrogen and liquid oxygen as fuel... (Score:5, Informative)
The article says the J2-X uses liquid oxygen and liquid hydrogen as fuel. Does that imply the byproduct of the J2-X is water vapor? The old Apollo rockets used kerosene. I know NASA used a lot of water to control heat and vibration for shuttle launches and other rocket tests (which is likely what you see in the video)... but is that also the exhaust gas here?
Most of the white stuff you see in the video is steam from cooling and sound supression systems. But, in EVERY combustion in air, even if burning pure hydrogen and oxygen, there is some amount of nitrous oxides produced from the nitrogen present in air. This is an inescapable fact of chemistry. But what you're seeing is water vapor.
Re:Why are they doing this? (Score:2, Informative)
Man-rating the Delta and optionally funding a heavy (modular) variant of the Delta and Falcon is the most cost-effective strategy. Unfortunately, it is about keeping the money flowing toward the districts that built the shuttle, not about cost-effective space exploration. Since the space program is a fairly unimportant political issue, congress gets away with it.
Sorry, you don't get it (Score:4, Informative)
Re:Smoke? (Score:5, Informative)
Mist, actually. Steam, which is water in its gas state, is invisible. The bit that you can see is actually an aerosol of water in its liquid state.
The mixture is often referred to as "wet steam", but it's the wet bit that you can see, not the steam bit.
Re:SLS: Cart before the horse (Score:5, Informative)
What is important is NOT the construction of a rocket, or even a mission. What is important is having tested designs, manufacturing lines, and having it be CHEAP. From that, you can move forward quickly. For example, it took musk 10 years to build his F9. It will take 2 years to build Falcon Heavy. And if things go well, then Musk will likely build Falcon XX in under 5 years. But the important thing is that Musk will build it CHEAP.
OTH, SLS is simply a continuation of Ares V. Same damn SRBs. Same SME. Same J2X. The difference is that SLS is simply being pushed now with a different name. But we already spent 7 years on Ares. Now to get a TEST launch of a 70 tonne system, it will be another 7 years. The first launch of a human? 10 years and over 20 billion just on the SLS. That does not include the 10 billion that we spent on ares already. Of course, SLS will die in about 2 years when Falcon Heavy works. The FH will take up 54 tonnes at that time. Musk is follow it with Raptor second stage which will give FH 70 tonnes. All by 2016. The real issue is that FH with the raptor will still cost around 1/10 of what the SLS costs to launch. That will lead CONgress to kill the SLS (thank god). Once CONgress will allow NASA to focus on doing BEO tech, THEN we can have missions. LOTS OF MISSIONS. But we need a stable of tested equipment and the ability to do it cheaply and quickly.
Re:Liquid hydrogen and liquid oxygen as fuel... (Score:4, Informative)
Re:SLS: Cart before the horse (Score:5, Informative)
Not just the Saturn - the Apollo CSM was already in development[1] and was in the process of morphing from being the lunar lander to being the command ship with a separate lunar lander. The (in)famous mode debate over direct ascent vs. EOR vs. LOR was already underway.
Few people realize that direct ascent was even in the race, because by 1962 it was already slipping into third place because it was believed that the booster required would be too large to build and fly within the state-of-the-art. The funny part is that NASA so badly underestimated the size and weight of the spacecraft[2] needed to reach the moon, the Saturn V of 1967 ended up being much larger than the Nova they didn't think could be built in 1962.
Precisely this. Kennedy and his advisers looked wide and deep at the various technology projects underway in the US at the time, and choose the lunar landing because a) it was In Space (the primary battleground), and b) considerable research and engineering had already been done. The various popular histories of the era even down to today merely repeat the propaganda of the time, that NASA started from more-or-less a standing start.
Indeed. And once the US got going, the Soviets fell ever further behind, and in some ways they never recovered. Even when it comes to space stations - the Soviets wouldn't beat either the total time accumulated or individual flight lengths until years after Skylab. (Which was essentially a program run with the scraps of the Apollo program.)
[1] Yes, Apollo predates Gemini by a wide margin - and NASA's decision to stick with the existing Apollo (what become the Block I Apollo) would come back to bite them in the butt.
[2] NASA's difficulties with estimating size, weight, budget, and schedule goes back a long ways.