08 May 2025, 17:12 [ UTC - 5; DST ]
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Username Protected
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Post subject: Re: Astra Launch Goes Sideways  Posted: 29 Aug 2021, 20:32 |
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Joined: 01/07/19
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Location: KGTU
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I am no rocket scientist, but seems they will never have enough thrust to get any payload into space even with all the engines working. Will one more working rocket engine make it feasible?
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Post subject: Re: Astra Launch Goes Sideways Posted: 29 Aug 2021, 21:36 |
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Username Protected wrote: They almost made orbit last time with all engines working, just neededed a bit more fuel. That's what shocks me. The calculation to determine how much fuel they need is simple, at least in rocketry terms. They should have known before launching if they had enough gas to get the ∆V they needed to make it to orbit. It's like they're tinkering in the garage to learn about rocketry.
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Post subject: Re: Astra Launch Goes Sideways Posted: 29 Aug 2021, 21:39 |
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Username Protected wrote: I am no rocket scientist, but seems they will never have enough thrust to get any payload into space even with all the engines working. Will one more working rocket engine make it feasible? They possibly would have a dummy payload aboard to simulate their suspected loads.
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Post subject: Re: Astra Launch Goes Sideways Posted: 29 Aug 2021, 22:56 |
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Joined: 12/03/14
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Username Protected wrote: Will one more working rocket engine make it feasible? Well, maybe. The Saturn V has 5 main engines. If only 4 of them light, the thrust is not quite equal to the mass, so going nowhere, at least not until the fuel load lessens. So yes, one engine can make all the difference. In the Saturn V case, it was basically all of the acceleration off the pad at the start. Mike C.
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Post subject: Re: Astra Launch Goes Sideways Posted: 31 Aug 2021, 08:29 |
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Username Protected wrote: Whoever had his/her finger on the abort button must have nerves of steel.
Jk, I presume an abort is mostly automated. It may be, but in fact they commanded the FTS. The reason that is imagined for the timing of the abort is in Scott Manley's video; there are designated 'no fly' zones down range from the launch site. By allowing it to fly to where it did, they could drop it into one of those rather than just randomly letting it fall wherever. Also by leaving it in flight they were able to clear the island and so not have to deal with the cleanup of the wreckage.
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Post subject: Re: Astra Launch Goes Sideways Posted: 31 Aug 2021, 09:37 |
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Joined: 04/26/13
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Username Protected wrote: another multi engine save? But they're five times more likely to have a failure.
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Post subject: Re: Astra Launch Goes Sideways Posted: 31 Aug 2021, 17:04 |
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Joined: 12/08/12
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Location: Ukiah, California
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Username Protected wrote: Will one more working rocket engine make it feasible? Well, maybe. The Saturn V has 5 main engines. If only 4 of them light, the thrust is not quite equal to the mass, so going nowhere, at least not until the fuel load lessens. So yes, one engine can make all the difference. In the Saturn V case, it was basically all of the acceleration off the pad at the start. Mike C.
Yes, with the Saturn V the hold down arms would not release until all five F-1 engines were confirmed to be at full thrust.
Once off the pad, at about 20 seconds (rocket getting lighter by about 28,000 lbs per second at full thrust fuel rate burn), the outboard four engines would cant outward slightly to align the thrust vectors towards the center of mass to provide some measure of stability if any one of those outboard engines were to fail. A mission abort at some point would be likely (from what I understand) but the rocket would be mostly vertical at the time.
Dan
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Post subject: Re: Astra Launch Goes Sideways Posted: 31 Aug 2021, 18:29 |
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Username Protected wrote: It's like they're tinkering in the garage to learn about rocketry. So Peter has moved on to rockets??
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Post subject: Re: Astra Launch Goes Sideways Posted: 31 Aug 2021, 19:55 |
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Joined: 04/26/13
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Location: Columbus , IN (KBAK)
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Username Protected wrote: It's like they're tinkering in the garage to learn about rocketry. So Peter has moved on to rockets??
We’ll, it barely got off the ground, it’s rate of climb and top speed were far below projections. It’s useful load at takeoff was about zero, and it never got near it’s published service ceiling. So, yeah, you might be on to something. 
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