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#620
by
Chris Bergin
on 15 Jan, 2020 21:26
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Video time!
A tour of Boeing's Starliner CST-100 Commercial Crew and Cargo Processing Facility (C3PF) at the Kennedy Space Center.
Featuring a facility tour, a look at the OFT Starliner that recently returned from her test flight and two Q&As with Tim Reith, Spacecraft Engineering Manager and Ramon Sanchez, Senior Operations Lead.
Filmed by Chris Gebhardt for NASASpaceFlight.com
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#621
by
erioladastra
on 16 Jan, 2020 17:54
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Could be. And to add speculation topping on speculation cake: it didnt show up in simulations because the simulations were started to simulate the flight. So the Atlas "startup" clock was virtually identical to the "launch" clock. The simulation just started with the launch, which makes sense simulation wise.
The other arguments though, that Starliner didnt detect the error of its ways, still stands. No matter how the data got wrong, if there is no consistency check on any step in a system like that, its time to go back to the drawing board.
This has been one of my biggest suspicions to date as well. While I was looking up some info about changes to the Atlas flight computer for this launch, I came across an incredibly suspicious number which *really* makes me suspect this is exactly what happened (from https://spaceflightnow.com/2019/11/06/ula-begins-stacking-unique-atlas-5-rocket-for-starliner-test-flight/):
The Atlas 5 countdown typically lasts nearly seven hours for a satellite launch. For Starliner missions, the countdown will run nearly 11 hours.
There's that magical 11 hour offset...
Pure coincidence.
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#622
by
SoftwareDude
on 16 Jan, 2020 17:58
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ULA would not change its interface because that would spread risk to all of its customers. Interfaces are a contract.
If I am not mistaken, Northrup built its own payload-adapter for Zuma and the F9 interface was a binary signal "Arrived". I can't imagine that ULA's interface is much different.
To be clear - I don't think we really know who to fault at this point, and it seems unlikely it'd be ULA - but this particular human-rated Atlas V is substantially different than most other Atlas V LVs. At the very least, there's an entirely new Emergency Detection System for detecting abort conditions (apparently disabled for OFT), among other changes for the human rating. So it would not be unreasonable to think maybe the interface is substantially different than most other Atlas V flights.
https://spaceflightnow.com/2019/11/06/ula-begins-stacking-unique-atlas-5-rocket-for-starliner-test-flight/
I wondered about the escape system not being activated. Why wouldn't Boeing and NASA want the escape system active as part of the test? Isn't this a dress rehearsal? It says to me that Boeing is still working to fix problems found in the escape system found in the previous abort test that they neglected to reveal. What else wasn't active? NASA is keeping Boeing's secrets regarding test readiness. The lack of transparency in protecting contractors including SpaceX is not good.
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#623
by
gongora
on 16 Jan, 2020 18:39
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SpaceX abort system wasn't active for the equivalent test either, just in monitoring mode. That's apparently how NASA wanted it on the first uncrewed flights.
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#624
by
ZChris13
on 16 Jan, 2020 20:29
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SpaceX abort system wasn't active for the equivalent test either, just in monitoring mode. That's apparently how NASA wanted it on the first uncrewed flights.
It's a good way to verify the system without risking it impacting the rest of the flight test, in my opinion.
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#625
by
SoftwareDude
on 16 Jan, 2020 20:36
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Impacting the rest of the test would be exactly the reason to enable it. No one wants to discover the impact with astronauts on board!
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#626
by
John Santos
on 16 Jan, 2020 20:56
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Impacting the rest of the test would be exactly the reason to enable it. No one wants to discover the impact with astronauts on board!
It makes more sense to run the abort system in "monitor mode". It would continuously record and report its status including when it would have triggered an abort if it had been in "active mode", but not actually abort. If all goes well (expected case), then the feedback from the abort system would show it watching and happy. If all goes well with the launch, but the abort system erroneously thinks it should have aborted, the engineers monitoring it will know, but everyone else will be happy and would be able to test all the many many other systems. If something goes wrong and the abort system should have triggered, from telemetry the engineers will know whether or not the abort system detected the abort condition. They won't get the spacecraft back (most likely), but they will be able to tell whether or not the abort system would have triggered when it should have.
If the abort system was active and the second condition prevailed (everything is fine, but an erroneous abort occurs), they would accomplish exactly zero mission objectives. (Testing the operation of the abort system was NOT an objective of the OFT. That is an objective of the various abort tests. Whether Boeing should have done an ascent abort test is an entirely different discussion.)
Not activating the abort system, but running it in "monitor mode" is definitely the way I would test its first flight. (I don't know if the abort system actually has a "monitor mode", but it would be relatively trivial to implement and would make perfect sense.)
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#627
by
abaddon
on 16 Jan, 2020 22:18
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SpaceX abort system wasn't active for the equivalent test either, just in monitoring mode. That's apparently how NASA wanted it on the first uncrewed flights.
Yes, but it
will be active during the in-flight abort test that is a precursor to manned flight. Boeing's will be active for the first time with crew on board. I am not saying that's a problem, but they aren't identical situations either.
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#628
by
Steven Pietrobon
on 17 Jan, 2020 04:37
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The Russian Soyuz LAS was active on the Proton and N-1 Lunar test flights. Most times, it was the only system that worked!
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#629
by
Coastal Ron
on 19 Jan, 2020 04:56
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I don't think we've heard why the Starliner is so dependent on the Atlas V for mission timing, but there is some information about how the Falcon 9 keeps track of where it is at during a mission, and I thought it would be of interest.
This comes from an interview that is referenced in
this NSF post. That post references a Reddit translation, and the relevant part is:
- how does a landing of Falcon-9 play out?
flip of Falcon-9 is such that the rotation is canceld by the Merlin, not the thrusters (thus ignition needs to be quite precise)
4-6g of acceleration if using 3 Merlins on empty stage
first stage has almost identical navigation hardware
-> gyroscopes (fibre-optical) & accelerometers
-> GPS (exemption from the hight-limit)
-> GPS primary, gyroscopes & accelerometers secondary (will diverge after approximately 1 minute due to measurement error)
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#630
by
Comga
on 19 Jan, 2020 06:29
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I don't think we've heard why the Starliner is so dependent on the Atlas V for mission timing, but there is some information about how the Falcon 9 keeps track of where it is at during a mission, and I thought it would be of interest.
This comes from an interview that is referenced in this NSF post. That post references a Reddit translation, and the relevant part is:
- how does a landing of Falcon-9 play out?
flip of Falcon-9 is such that the rotation is canceld by the Merlin, not the thrusters (thus ignition needs to be quite precise)
4-6g of acceleration if using 3 Merlins on empty stage
first stage has almost identical navigation hardware
-> gyroscopes (fibre-optical) & accelerometers
-> GPS (exemption from the hight-limit)
-> GPS primary, gyroscopes & accelerometers secondary (will diverge after approximately 1 minute due to measurement error)
Any relevance of this quote, or anything in the interview, to Starliner and Atlas escapes me.
Can you be more explicit?
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#631
by
Vettedrmr
on 19 Jan, 2020 10:41
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Perhaps the relevance is thinking that Atlas' nav & control systems were similar to Falcon's? In any case, that transcript was enjoyable reading, thanks for sharing!
Have a good one,
Mike
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#632
by
SoftwareDude
on 20 Jan, 2020 19:21
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I am trying to understand what happened with the Boeing test. We know a little about how SpaceX Second Stage interfaces with the payload adapter because of the Zuma anomaly. The SpaceX interface comprises a single bit electrical signal "arrived". Given this simplicity, I imagine that SpaceX added another one-bit electrical signal, "abort". Maybe a code accompanies it for logging; who knows? I am wondering about the general nature of Boeing's interface. Any educated guesses are welcome.
My questions are,
1. Does anyone know what ULA has? regarding an interface? Is it simple, like SpaceX or more complex?
2. What would be the purpose of sharing a timer count from the booster? One cannot set a hardware timer with a value. The way software sets a timer is to take the current value, different between timers, as time=0. So I'm not sure what Boeing means by the timer is set wrong. Does anyone have ideas on this?
3. The RCS was eliminating dead space as if the OMT were in a burn but we know they weren't. Does this mean there was a timer that initialized properly and one that did not?
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#633
by
gongora
on 20 Jan, 2020 19:38
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I am trying to understand what happened with the Boeing test. We know a little about how SpaceX Second Stage interfaces with the payload adapter because of the Zuma anomaly. The SpaceX interface comprises a single bit electrical signal "arrived".
The SpaceX interface is not a single wire.
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#634
by
hplan
on 20 Jan, 2020 19:52
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I don't think we've heard why the Starliner is so dependent on the Atlas V for mission timing, but there is some information about how the Falcon 9 keeps track of where it is at during a mission, and I thought it would be of interest.
This comes from an interview that is referenced in this NSF post. That post references a Reddit translation, and the relevant part is:
- how does a landing of Falcon-9 play out?
flip of Falcon-9 is such that the rotation is canceld by the Merlin, not the thrusters (thus ignition needs to be quite precise)
4-6g of acceleration if using 3 Merlins on empty stage
first stage has almost identical navigation hardware
-> gyroscopes (fibre-optical) & accelerometers
-> GPS (exemption from the hight-limit)
-> GPS primary, gyroscopes & accelerometers secondary (will diverge after approximately 1 minute due to measurement error)
Any relevance of this quote, or anything in the interview, to Starliner and Atlas escapes me.
Can you be more explicit?
Perhaps the relevance here is that sanity checks are possible: it's possible for a spacecraft to determine its location, height, speed, acceleration, etc.
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#635
by
John-H
on 20 Jan, 2020 21:25
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Sometimes the problem can be too many sanity checks. Perhaps the mission scheduling system is working fine, but for additional safety, someone included the code "if the mission elapsed time is not in the window 5-20 minutes, inhibit the engine firing for additional security".
John
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#636
by
SoftwareDude
on 20 Jan, 2020 22:59
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I am trying to understand what happened with the Boeing test. We know a little about how SpaceX Second Stage interfaces with the payload adapter because of the Zuma anomaly. The SpaceX interface comprises a single bit electrical signal "arrived".
The SpaceX interface is not a single wire.
I am trying to find a source for the single wire. My memory is that it was a tweet from Elon.
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#637
by
gongora
on 20 Jan, 2020 23:22
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I am trying to understand what happened with the Boeing test. We know a little about how SpaceX Second Stage interfaces with the payload adapter because of the Zuma anomaly. The SpaceX interface comprises a single bit electrical signal "arrived".
The SpaceX interface is not a single wire.
I am trying to find a source for the single wire. My memory is that it was a tweet from Elon.
https://www.spacex.com/sites/spacex/files/falcon_users_guide_10_2019.pdfAs a standard service, Falcon launch vehicles provide two in-flight disconnect electrical interface points located at the
payload separation plane. Connector locations and pin designation will be determined during the mission integration
process. SpaceX will supply 37- or 61-pin electrical connectors and will provide the payload-side connector halves to the
customer. Alternatively, the customer can supply mission-unique electrical connectors and provide the launch vehicleside connector halves to SpaceX.
...
Separation device commands are used to initiate spacecraft separation from the second stage. Falcon launch vehicles
can provide up to 36 separation device commands, typically implemented as up to 18 redundant commands. Up to 96
additional (48 redundant) commands can be accommodated as a nonstandard service; please contact SpaceX for
details.
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#638
by
woods170
on 21 Jan, 2020 08:06
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Pardon me for asking, but why are we discussing SpaceX payload adapter interfaces here? This thread is about Starliner.
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#639
by
jpo234
on 21 Jan, 2020 15:24
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