stevedonie t1_j81g75q wrote
So they used nearly all of the engines, but only achieved half of max thrust. Is that because they didn't throttle the engines to 100%, or is there some other reason?
Anthony_Pelchat t1_j81gog3 wrote
Correct. Engines throttled down to around 50%.
acksed t1_j81xss1 wrote
I thought it was a little too sedate for full thrust.
RedditorFor8Years t1_j81zds5 wrote
Will they be doing 100% thrust, full mission duration test in the future?
Shrike99 t1_j82bang wrote
I doubt the launch pad would survive such a test. I'm not sure there's a facility in the world that could.
The test stand at NASA's Marshall Center was able to handle the Saturn V first stage static firing for a similar duration to Superheavy (~2.5 minutes), but Superheavy's energy output is about 2.7 times greater.
b-Lox t1_j83odv2 wrote
For such a test the limitation is not the thrust level, but the facility where it happens yes.
The Marshall test stand is specifically built for handling these kind of tests, with a huge flame diverter, and hold-down systems that are specific for the task.
It will not happen because they don't want to risk the launch table if there is a problem, but you can build the facility to handle the force, no problem. Just a question of funds, location and schedule, not thrust.
amitym t1_j83wj5k wrote
Yeah right on.
To understand why it's no problem as this commenter said, remember that the thrust itself is comparable to forces easily within the usual realm of civil engineering tasks.
We don't use rockets to get to space because they generate cosmically far-fetched amounts of thrust, but rather because they can generate thrust reliably and continuously over an extended period, largely indifferently to the environment around them.
It's a similar principle as how a jet liner with engines capable of transporting hundreds of people at Mach 0.9 can be held in place by a couple of wooden chocks.
[deleted] t1_j83yjp4 wrote
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actfatcat t1_j83r4fn wrote
2.5 minutes? My watch must be slow.
LurkerWithAnAccount t1_j83vw29 wrote
You have to convert from Thrust Minutes to Earth Seconds.
rdhatt t1_j84x9rs wrote
~2.5 minutes is the total burn time of the Saturn V first stage engines after liftoff.
Shrike99 t1_j860j84 wrote
S-IC nominal burn time is 150 seconds, or exactly 2.5 minutes.
Superheavy nominal burn time is 169 seconds, or 2.8 minutes.
Though that figure may have been for the 29 engine version, the 33 engine version might be a bit less since it burns fuel quicker.
Either way, it's close enough to the Saturn V that I think it's fair to call it a 'similar' duration.
Anthony_Pelchat t1_j8234dd wrote
Not on the ground. Remember, even at this low amount of thrust, it was still more than the Saturn V produced when it sent humans to the Moon. Full mission duration isn't needed as each engine is already tested that way individually.
[deleted] t1_j821uwo wrote
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