Author Topic: RLVs and the quest for "airline-like operations"  (Read 8931 times)

Offline john smith 19

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Re: RLVs and the quest for "airline-like operations"
« Reply #60 on: 06/10/2018 06:05 PM »
IIRC  the Saturn was running a backup copy of the flight guidance on an Apollo Guidance Computer which took over. IOW the computer was on a payload. Since this was not happening with the Atlas, range safety destroyed it.


No, the Saturn launch vehicle guidance system was unaffected by the strike.  The spacecraft avionics, including the AGC, were knocked offline by the surge.
The perils of relying on memory without checking facts.
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Offline john smith 19

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Re: RLVs and the quest for "airline-like operations"
« Reply #61 on: 06/10/2018 06:08 PM »
They still are developed months in advance.  DoLILU, which has been available in most vehicles since the '70s, only provides for adjustments for winds in the first 100k ft.  The trajectory is basically the same.
I'm quite surprised at that. NASA made quite a point of DoLILU. They gave the impression all other ELV's had their ascent programs designed months in advance and once it was out of spec it was months before it could be reused.
« Last Edit: 06/10/2018 06:25 PM by john smith 19 »
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline Jim

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Re: RLVs and the quest for "airline-like operations"
« Reply #62 on: 06/10/2018 06:13 PM »
The climb into LEO is basically the same for most launches of a specific vehicle, especially for a GTO comsat. There isn't much to change

Offline laszlo

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Re: RLVs and the quest for "airline-like operations"
« Reply #63 on: 06/10/2018 08:06 PM »

1.  It had nothing to do with being "certified for instrument flying".  Most of the entry is done on instruments.  The orbiter was more instrumented than "certified" aircraft. 
a.  The main reason was moisture in the clouds
b.  NASA wanted visual cues since there was no go around capability.
Which comes down to Shuttle being VFR rated only.  Different words, same result.  :(
...

IMC is not the same as IFR.
VFR is not the same as not IFR.
Not IMC is not the same as VFR.

IMC is instrument meteorological conditions, not enough visibility to use external references.
VFR is visual flight rules, which is navigation and control procedures using external visual references.
IFR is instrument flight rules, which is navigation and control procedures using internal instrument references.

You can pretty much mix and match those three in any combination. For example, it is perfectly possible to be flying VFR in IMC. Typically this is an emergency situation. You can also fly IFR in non-IMC conditions. This is routinely done for traffic, rather than weather avoidance. It's also the safest option for night flying. IFR in IMC is the safe option for flying through clouds (at least through certain types of clouds).

So while the Shuttle was not supposed to fly through clouds, it could if it had to and it was flying under IFR regardless.

Offline spaceman100

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Re: RLVs and the quest for "airline-like operations"
« Reply #64 on: 11/08/2018 03:25 PM »
Could the craft also be "aeroplane" like ? 8)

Offline vulture4

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Re: RLVs and the quest for "airline-like operations"
« Reply #65 on: 11/12/2018 11:27 AM »
One of the factors leading NASA to want to avoid IMC on landing was the decision to fly the landing by hand. For airline operation landing in extremely low visability conditions requires either "synthetic-vision" instrument guidance to the pilot, which was not available at the time, or autoland. Ironically autoland was available for commercial aircraft even early in the Shuttle program and was actually installed on the Orbiters during the later part of the program, but was never tested in VMC, so it could never be "certified" for IMC. Since both the X-37 and the Falcon booster land autonomously, possibly this psychological barrier would be less of a factor in the future.

Online CameronD

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Re: RLVs and the quest for "airline-like operations"
« Reply #66 on: 11/12/2018 10:30 PM »
One of the factors leading NASA to want to avoid IMC on landing was the decision to fly the landing by hand. For airline operation landing in extremely low visability conditions requires either "synthetic-vision" instrument guidance to the pilot, which was not available at the time, or autoland. Ironically autoland was available for commercial aircraft even early in the Shuttle program and was actually installed on the Orbiters during the later part of the program, but was never tested in VMC, so it could never be "certified" for IMC. Since both the X-37 and the Falcon booster land autonomously, possibly this psychological barrier would be less of a factor in the future.

Autoland has been around commercial aviation since the 1970's at least, but without the ability to abort a landing on last-second equipment failure (either on-board or on-airport) the safest way to land an aeroplane is still flying by hand (VFR).  For this reason I believe most (all?) commercial airlines flying today insist that their pilots hand-fly at least the last part of the landing (from short final) unless they have a really good reason not to.

AIUI, the main reason autoland was useless to the Shuttle program was simply that there was no way to abort the landing go around and try again (it's a glider!), so it's not a psychological barrier - it's a safety one: it seems the astronauts prefer to get back in one piece, rather than smack into the ground at 200kts whilst happily exclaiming "look ma, no hands!".

EDIT:  https://en.wikipedia.org/wiki/Autoland

« Last Edit: 11/12/2018 10:35 PM by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

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