A Space & astronomy forum. SpaceBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » SpaceBanter.com forum » Space Science » Policy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Commercial Crew



 
 
Thread Tools Display Modes
  #61  
Old July 14th 19, 07:51 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,056
Default Commercial Crew

In article ,
says...

On 2019-07-14 09:05, Jeff Findley wrote:

monitor itself to insure it's on the right trajectory. If its not, it
initiates the FTS (flight termination system) in order to make sure that
it doesn't go completely off course which might endanger people who are
outside of the exclusion zone underneath the intended flight path.


My understanding is that FTS is triggered only when the rocket strays
from a cone of acceptable trajectory. So it isn't triggered as soon as
it strays off nominal trajectory since there could still be hope it
recovers. So there is logic involved in this.


Yes there is logic involved. I don't know what the error bars are, so I
didn't mention them.

Of course it does. But that does not negate the fact that the second
stage needs to know its trajectory all the way to orbit. So it would
make sense that the second stage computers are the ones to insure
mission success.


Second stage computers only need situational awareness, aka a copy of
telemetry feed and comms with first stage computers. First stage
computers needs the logic in order to land, swo it can't be a slave to
second stage.


That's not how these things work. Any 2nd stage hardware necessary for
tracking the trajectory will be on and verified as functioning properly
even before launch. The second stage is not going to wait to turn on
things like ring laser gyros and GPS receivers at first stage
separation. To insure mission success, they'll be on and operating
before first stage ignition. You don't want to get to first stage
separation only to find out your second stage guidance system is effed.

Landing happens *after* first stage separation. It's
a secondary objective not directly tied to mission success.


But still critical one because first stage could go nuts and require
termination instead of crashing in downtown Cocoa Beach.


Yes, the first stage has a flight termination system. We covered that
at length.

Why would the first stage ever give a damn about the second stage?


It needs to know if second stage is healthy or has exploded or whatever.
It should be part of the logic to decide whether to self destruct or not.


All it really needs is that one wire from the upper stage that has
positive voltage on it that means everything is "a.o.k.", else it drops
to zero voltage to initiate an abort. The logic to monitor the health
of the second stage wouldn't be in the first stage. It would be in the
second stage, where it belongs. This is because the 2nd stage has to
monitor itself after first stage separation.

It's going to know right away because its going to lose the link to the
second stage and its engines will shutdown.


Exploding tank in stage 2 might not sever the "voltage or not" line.
Consider Apollo 13. They lost one side of the command module but much of
it remained functional.


Then the computer in the second stage would detect the tank going
"boom" and initiate an abort, which would be sent to both the Dragon 2
and the first stage. Again, neither the Dragon 2 nor the first stage
gives a damn about *why* the abort was initiated.

We've gone over this what feels like 100 times. The "abort now"

wire
going to the capsule that should have a positive voltage during launch



I really doubt "man rating" a rocket would accept a single wire as the
one commanding the catrastophic abort. If you insist on an old analogue
voltage or no voltage wire, they at the very least put 3 such wires each
120 apart around the rocket and have computers at least requite loss of
voltage on 2 wires for more than x milliseconds.


Fred covered what happens when you have multiple wires. That may very
well be the case. But if there are multiple wires, zero voltage on one
of them would trigger an immediate abort. A voting system would not be
allowed when interpreting the multiple abort signals. That's because if
something in the upper stage triggered an abort, don't want to count on
the redundant wires all going to zero voltage. You want to get the eff
out of there *right now*.

But I really doubt that Musk would have gone for 1950s analogue stuff on
a modern rocket, Especually since Falcon9 would not have had such a wire
running in cargo missions that don't have abort.


We're talking about the abort system, not the flight control system.
When something absolutely has to work to save astronauts' lives, KISS -
keep it simple, stupid.

Consider also that there must be some delay betwene initiation of
Dragon2 abort, and initiation of the self destruct charges. So it can't
be the same wire.


We're not talking about a delay in the charges. That would be the job
of the destruct system, not the abort system. The destruct system would
receive the abort signal, wait the appropriate amount of time to let the
Dragon 2 escape, then blow the tanks wide open.

When designing hardware like this, you must be careful to keep the roles
and responsibilities separate.

That is because the initiation of an abort really only needs one signal
wire (and a ground as a voltage reference). We've both been telling you
this from the beginning, but you simply won't listen.


Because the use of analogue unreliable connections is not credible in a
man rated system built in 21st century. And when the user Guide mentions
"command" which implies a data packet sent.


It's not really analog, it's digital. Every single logic chip ever made
has a voltage threshold to distinguish between a 1 and a 0. Exactly
what that voltage would be would be determined by the engineers
designing the system. At any rate, an ON/OFF signal is digital, not
analog.

Sure you could let the capsule monitor telemetry from the launch vehicle
during the flight. But that is *separate* from the abort system.


So you admit Dragon2 might get telemetry? The other guy doesn't admit to it.


No, I don't know if it does or does not. What I do know is that no sane
engineer would commingle the telemetry system with the communication of
an abort. Again, keep the hardware separate since an abort is a
critical function that must work even if the telemetry system fails to
work as designed. You have to cover the case where the telemetry system
is saying everything is o.k. due to some unforeseen problem, despite the
fact that something has gone horribly wrong (i.e. structural failure of
some sort which severs the abort wire(s)).

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
Ads
  #62  
Old July 14th 19, 11:14 PM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Commercial Crew

JF Mezei wrote on Sun, 14 Jul 2019
13:52:32 -0400:

On 2019-07-13 18:36, Fred J. McCall wrote:

You say that like it means something. What you've argued is that
because your lungs work your brain isn't important.


You have argued that stage II has the brains. I have argued they each
have brains. And stage 1 needs brains to laund by itself while stge II
is busy doing orbit insertion.


No, that is not what you have argued at all. YOU have argued that all
the pieces parts (first stage, second stage, capsule) must have the
SAME brains and all get the SAME data. What you have argued is
bull****.

Again you seem to think you have a point when you do not. The main
engine control computers are at the top of the second stage. If they
stop talking, it's pretty simple logic for the first stage to know to
shut down.


If the brains are in stage II, then how does Stage 1 have the brains to
know to stop its engines? And how does Stage I know how to land by itself?


If your brains are in your head, how do your heart and lungs know to
keep working?

The range safety stuff is all in the second stage. Again, simple
logic for the first stage to fire it when the second stage stops
talking.


The text of user guide menbtions C band radios in each stage. Consider
that while landing, range safety might be needed to blow up stage I.


Consider that you are an idiot and might need to blow yourself up.
Nobody (but you) has said there is ZERO logic and NO computers in
stage one. You then pretend WE said that and argue against your own
illiterate interpretations.

Crew Dragon doesn't get telemetry from the first stage whether Stage 2
is there or not.


So the crews can't tell if all engines are running normally? Can't tell
if gimbaling working properly? can't look at pressures and fuel levels?


Why would they need to and what could they do with the data?

Redundancy and disaster tolerance in logic.

WHICH YOU DO NOT WANT IN A SYSTEM LIKE THIS!


This is no missile. Ub fact, "man rating" a rocket is all about making
it different from single use missile.


You're a ****ing idiot. The LAST thing you want in an automatic
escape system is redundancy that leads you to NOT abort.

"Falcon vehicles are capable of detecting 6 separation events through
breakwire pairs, and a separation indication signal for each will be
included in launch vehicle telemetry.


"separation indication signal" = detection of breakwire is made by
sensors and it is those sensors that create the telemetry event. This
isn't some wire that goes all the way to the CPU.


Thank you, Captain Obvious. Practically NO data wires run "straight
to the CPU". Do you know nothing about computers?


Also, a breakwire loop does not imply complex connector between stages.
Simply implies a sensor on one side with a wire looping thorugh the
separation. When wire breaks, the sensor on one side detects the breek
and sends signal.


Again, thank you, Captain Obvious.


This means that Dragon2 would not know of a separation event because
some line dropped to 0 volts since the breakwire loop between stage 1
and 2 is only a short loop across the divide and doesn't travel the
lentght of stack. The only way Dragon2 would know of a separation even
is if telemetry is sent to it and would include the event detected by
the sensor on one side of such a loop.


Absolute ignorant bull****. PULL YOUR HEAD OUT OF YOUR ASS! You just
asserted that Dragon 9 cannot work, since the payload can never know
if it has separated from the booster. Same logic (or lack thereof)
applies. If you were THINKING rather than ARGUING you would realize
that the simplest way to implement this sort of thing is to have a
sensor on each 'side'. When the wire breaks or is commanded to zero
both sides know. No telemetry required.

But not in things like escape systems, where what you want is a single
"we're ****ed" vote sending you on your way rather than having the
capsule destroyed because it's hanging around waiting for election
results.


All the more import5ant for Dragon2 to get a copy of telemetry so it can
see events just priorr to looss of telemetry and make a decision by
itself should telemetry and/or commands from the computers below be lost.


Absolute horse****! Why do you think "loss of telemetry" is
sufficient to know but keep ignoring that loss of a single discrete is
also sufficient to know and a much more robust system? The capsule
doesn't need to know anything other than that it has been told to get
the **** out of there.

You're comparing apples and aardvarks again. The Shuttle had big
pieces of its flight envelope where there was little chance of
survival if something went wrong. Most 'abort' scenarios were pretty
much all manual. NEITHER of those things is true of the Falcon 9/Crew
Dragon.


I was p]roviding an example where crew compartment having telemetry and
thus being able to advise crew things were slowly startuing to streay
from normal was a good thing instead of just some instant "ABORT"
without warning.


Ask yourself what they can do with the data if they have it. The
answer is 'nothing'.

describe above is there for EXTERNAL range safety termination of the


believe that an internally commanded activation of the FTS works that
way?


Why should it be any different?


Because it's stupidly more complex than it needs to be.


Range safety implies some computer
sending commands in the right sequence to turn off engines and then fire
pyrotechnics in a variety of places. Whether that computer receives
commands via radio or from another on-board computer who had decided the
rocket was misbehaving should make no difference. But when the command
to activate rage safety is made by computers, once would assume some
vote is taken to ensure it isn't 1 rogue computer that lost telemetry
feed that issues a "kaboom" command while the other 2 computers are
getting telemetry confirming rocket is functionaing perfectly normally.


Your preceding remarks are totally on their ass. Why would you want a
'vote'? Suppose one computer says to fire the FTS and the other says
not to. Further suppose that the one that says not to 'wins the
election'. Now suppose that that computer is the one that is wrong.
Congratulations, you just fragged Miami. That's why there is no
'vote'. Because you want ANY decision to fire the FTS to be executed
immediately. And we have, in fact, had rockets activate their FTS
when nothing was wrong due to a computer/sensor error on board the
vehicle. This simple fact shows that your whole scenario above is
bull****.

How do you think signals get around? Magic?


You seem to imply that each type of signal is a physical copper wire
with 0 or 1 voltage in it.


I'm not responsible for what you infer because you're a ****ing
illiterate idiot.


I am arguing thsi ios not the case in modern
systems because it would be a redundant data link transmitting formatted
data between stages in order to limit how many physical connectors are
needed.


For an abort you need one wire (in the simplest case). What you
probably actually have on Falcon 9 is two independent loopback command
wirss and the abort is triggered if EITHER of them signals abort.

The connectors and wires already exist.


How many strangs of copper need to be connected is what matters and was
a problem in Shuttle because they had built it the way you say with many
many separate connectors and that caused issues.


See below. Try actually reading and understanding the answers that
people give you instead of just searching for grist for your little
argument machine.

"Up to 96 additional (48 redundant) commands can be accommodated as a
nonstandard service; please contact SpaceX for details."


Commands implies a data connection, so you own post negates your
insulting of my contention they hacve data connections going both ways.


And what is 'data', you yammerhead? It's a voltage. DUH!

You argued wrong. No 'software' change is required. It's all manual
steps.


In a "fuel before boarding" scenario which was before SpaceX convinced
NASA to allow fuel after boarding, code would need to inhibit triggering
or arming of abort (consider case where mistake happened and abort was
armed).


Then it armed early and you've ****ed up.


So for sure there is code in there to hadnle such cases. If I
can think of a failure mode, than SpaceX engineers thought of it.


Utter bull****! Do you seriously believe there are zillions of lines
of 'software interlock' code on the vehicle? You're delusional!

Again, assume the implementers are NOT cretins.


Which is why I argue that the system is far more robust that you think
it is. This is no single use missile whose sole purpose is to destroy
itself.


Except you argue that they ARE cretins, or at least share your level
of ignorance about engineering.

Ah, you finally mention what you're talking about by name. Would you
be surprised to learn that 1553 is not slow and is used almost
everywhere in everything that flies?


It's used where military is present. Not used commercially. And yes, it
is slow by today's standards. At much higher speeds, latency is lower.


Bull****. Virtually every satellite launched in the Western World
uses it, both military and commercial. The French (of course) have
their own virtually identical system (DIGIBUS) and obviously the
Chinese (GJV289A) and the Russians (GOST R 52070-2003) have their own
similar systems.

If something faster is needed
Firewire will often be used.


Wasn't aware Firewire was even used for such purposes. It isn't used for
normal comp]uting anymore, hasn't for a long time.


You're not aware of a lot of things. You typically don't see it
listed as 'Firewire', but rather as IEEE 1394.

Then the situation won't be recognized by people, either.


This assumes every possible scenario has been considered by the
engineers who programmed the computers and thought in advance of
installing sensors for every possible scenario.


If the scenario wasn't considered, nobody will recognize it when it
happens and you'll only find it with a post mortem.


Say a bird hits the widshield at speed and there is a big crack in it.
Cabin pressure would still be OK, but crew might decide to abort because
they know the window won't survive. Do they wait for window to break and
cabin pressure sensors to detect bad event and trigger abort, or do they
manually trigger abort before window breaks?


Neither, since the crew can't "know the window won't survive".


Engineers spend a lot of time planning on handling as many failure modes
as they can possibly think of. But that doesn't mean that they can
handle 100% of them.


Which means humans won't know about them to recognize them when they
happen.

2b2) It wasn't a data anomaly and you really are ****ed and everyone
dies.


If two computers have valid telemetry that show nominal flight profile,
and 3rd computer has lost telemeytrry eother fully or partially, or
getting wrong data, then the 2 computers win. This points to the 3rd
computer being the fault instead of the rocket's engines, tanks etc.


And that, my children, is how you build systems that 'fail deadly'.


That is the whole point of redundancy and voting between computers.


Which you don't do on safety critical actions like crew aborts and
Flight Termination.


If majority of computers get data that shows rocke is not nominal, then
the decision to abort is straightforward.


And if they don't and the capsule hangs around waiting for all the
hanging chads to be analyzed everyone dies.


And this is where telemetry to Dragon 2 capsule is important: if they
see that there is disagreement wih computers and that one is
recommending abort, they can then make judgement call on how to handle
situation and have hand on the big red abort button just in case.


Utter bull**** and SpaceX engineers obviously disagree with you.


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
  #63  
Old July 14th 19, 11:32 PM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Commercial Crew

JF Mezei wrote on Sun, 14 Jul 2019
14:09:30 -0400:

On 2019-07-14 09:05, Jeff Findley wrote:

It's going to know right away because its going to lose the link to the
second stage and its engines will shutdown.


Exploding tank in stage 2 might not sever the "voltage or not" line.


So the Flight Computer detects the event (or the run up to it) and
pulls the 'voltage or not' line to 'not' and everyone gets the ****
out of there.


Consider Apollo 13. They lost one side of the command module but much of
it remained functional.


What alternate universe do you live in? They didn't lose "one side of
the command module". They had a fuel cell external to the pressure
hull explode. This cost them electrical power in the Command Module,

We've gone over this what feels like 100 times. The "abort now" wire
going to the capsule that should have a positive voltage during launch


I really doubt "man rating" a rocket would accept a single wire as the
one commanding the catrastophic abort.


That's because you're an ignorant git.


If you insist on an old analogue voltage or no voltage wire, ...


Uh, what do you think a binary 'one' looks like on a typical computer
data line? It's a voltage, you ignorant git. A binary 'zero' is
typically 'no voltage'.


... they at the very least put 3 such wires each
120 apart around the rocket and have computers at least requite loss of
voltage on 2 wires for more than x milliseconds.


And there's the system that would NOT be man rated.


But I really doubt that Musk would have gone for 1950s analogue stuff on
a modern rocket, Especually since Falcon9 would not have had such a wire
running in cargo missions that don't have abort.


Go read the FUS again.


Consider also that there must be some delay betwene initiation of
Dragon2 abort, and initiation of the self destruct charges. So it can't
be the same wire.


First, why does there need to be a delay? Second, why can't the
signal be the same wire even if you want a delay?

That is because the initiation of an abort really only needs one signal
wire (and a ground as a voltage reference). We've both been telling you
this from the beginning, but you simply won't listen.


Because the use of analogue unreliable connections is not credible in a
man rated system built in 21st century. And when the user Guide mentions
"command" which implies a data packet sent.


What we've described is MORE reliable than any of the Rube Gloldberg
systems you've proposed. Again, tell me what a binary 'one' looks
like on a wire?


Just because old missiles designed in the 1950s used such an alague
system doesn't mean Falcon9 added this old mechanism to support Dragon2.


You seem to not understand how the hardware in a digital system works.

Sure you could let the capsule monitor telemetry from the launch vehicle
during the flight. But that is *separate* from the abort system.


So you admit Dragon2 might get telemetry? The other guy doesn't admit to it.


You're one of those idiots that thinks not using President Trump's
name is some sort of 'resistance', too, aren't you? I don't "admit to
it" for the same reason I don't "admit to" the first stage getting all
the telemetry from the second stage; because there's no reason for it
and it would require special data lines that simply aren't normally
there on a Falcon 9. I find it hilarious (in a sad way) that you
insist that simple 'breakwire' signaling is too complicated despite
there being almost 100 command lines (note, COMMAND LINES) between the
second stage and the payload (regardless of whether that payload is a
Crew Dragon or not) but somehow believe sending all the vehicle
telemetry up to the capsule can be handwaved away.


--
"Ordinarily he is insane. But he has lucid moments when he is
only stupid."
-- Heinrich Heine
  #64  
Old July 16th 19, 03:58 PM posted to sci.space.policy
Greg \(Strider\) Moore
external usenet poster
 
Posts: 676
Default Commercial Crew

I don't normally try to top-post,but there's not a specific comment I want
to respond to but the general idea.

JF: Here's the thing (and Jeff and Fred will correct me if I'm wrong) but
believe it or not, redundancy is NOT always better.
I'll give you two examples"

What's safer for a small aircraft, one engine or two?
Most people will immediately leap to "two". But, the answer is not that
simple.
Sure, if one engine fails, you still have another, but...
You double your chances of failure. That's a con.
AND... in the hands of someone w/o enough experience, you now have an
aircraft that immediately wants to flip into the direction of the remaining
engine. This can be bad, especially during take-off. So, a 2nd engine does
NOT automatically make things safer. The redundancy can in fact make things
LESS safe. (but keep in mind it's not purely a binary decision when
designing an aircraft).

I'll give you another more personal case.
I do vertical caving. I teach vertical caving. We use something called
"Single Rope Technique" (SRT). Basically we rappel and climb on a single
rope. There is NO belay rope.
This is often SAFER than having a belay rope. There's a multitude of
reasons, but a big one is in many pits, the air will swirl up the pit. This
and the motion of the climber (or rappeler) can cause the rope you're on to
twist. If you have a single-rope this can lead to a bit of dizziness, but
that's about it. With a 2nd rope, they will start to braid each other. This
can stop the person completely so they can't move. They are now stuck on
the rope. Again " redundancy" is a bad choice here.

With the case of Falcon 9, you're confusing the logic to decide if there's
an abort with the order to carry it out.
There is almost certainly redundancy in sensors (such as the SSME's had)
because you don't want a flakey sensor triggering an abort. BUT, once the
decision is made, you want it as simple as possible a single wire with
voltage is that simple.

Yes, is it possible that magically the voltage on that wire drops to zero
when it shouldn't and triggers an abort? Sure, I suppose. And in that case
the astronauts get a wild ride and a story to tell.
But what would be worse is if you have 2 or more wires and one doesn't drop
to zero and you do NOT abort when you need to. In that case the astronauts
get an obituary and their families are left to tell stories.

This is why Jeff at one point uses the term fail-safe. An abort is a "bad
day" event" but should be a survivable, even if it's a mistake. A failure to
abort when you should have, is potentially a company ending event. So if
you're going to fail, fail in a way that's safe for the crew.


"JF Mezei" wrote in message ...

On 2019-07-14 09:05, Jeff Findley wrote:

monitor itself to insure it's on the right trajectory. If its not, it
initiates the FTS (flight termination system) in order to make sure that
it doesn't go completely off course which might endanger people who are
outside of the exclusion zone underneath the intended flight path.


My understanding is that FTS is triggered only when the rocket strays
from a cone of acceptable trajectory. So it isn't triggered as soon as
it strays off nominal trajectory since there could still be hope it
recovers. So there is logic involved in this.


Of course it does. But that does not negate the fact that the second
stage needs to know its trajectory all the way to orbit. So it would
make sense that the second stage computers are the ones to insure
mission success.


Second stage computers only need situational awareness, aka a copy of
telemetry feed and comms with first stage computers. First stage
computers needs the logic in order to land, swo it can't be a slave to
second stage.






Landing happens *after* first stage separation. It's
a secondary objective not directly tied to mission success.


But still critical one because first stage could go nuts and require
termination instead of crashing in downtown Cocoa Beach.

Why would the first stage ever give a damn about the second stage?


It needs to know if second stage is healthy or has exploded or whatever.
It should be part of the logic to decide whether to self destruct or not.


It's going to know right away because its going to lose the link to the
second stage and its engines will shutdown.


Exploding tank in stage 2 might not sever the "voltage or not" line.
Consider Apollo 13. They lost one side of the command module but much of
it remained functional.


We've gone over this what feels like 100 times. The "abort now" wire
going to the capsule that should have a positive voltage during launch



I really doubt "man rating" a rocket would accept a single wire as the
one commanding the catrastophic abort. If you insist on an old analogue
voltage or no voltage wire, they at the very least put 3 such wires each
120° apart around the rocket and have computers at least requite loss of
voltage on 2 wires for more than x milliseconds.

But I really doubt that Musk would have gone for 1950s analogue stuff on
a modern rocket, Especually since Falcon9 would not have had such a wire
running in cargo missions that don't have abort.

Consider also that there must be some delay betwene initiation of
Dragon2 abort, and initiation of the self destruct charges. So it can't
be the same wire.


That is because the initiation of an abort really only needs one signal
wire (and a ground as a voltage reference). We've both been telling you
this from the beginning, but you simply won't listen.


Because the use of analogue unreliable connections is not credible in a
man rated system built in 21st century. And when the user Guide mentions
"command" which implies a data packet sent.

Just because old missiles designed in the 1950s used such an alague
system doesn't mean Falcon9 added this old mechanism to support Dragon2.

Sure you could let the capsule monitor telemetry from the launch vehicle
during the flight. But that is *separate* from the abort system.


So you admit Dragon2 might get telemetry? The other guy doesn't admit to it.

  #65  
Old July 19th 19, 12:14 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,056
Default Commercial Crew

In article ,
says...

On 2019-07-16 10:58, Greg (Strider) Moore wrote:

JF: Here's the thing (and Jeff and Fred will correct me if I'm wrong) but
believe it or not, redundancy is NOT always better.


There is almost certainly redundancy in sensors (such as the SSME's had)
because you don't want a flakey sensor triggering an abort. BUT, once the
decision is made, you want it as simple as possible a single wire with
voltage is that simple.


Then you need 3 wires to confirm to the other stages that a command to
abort is being sent instead of just a flaky connection due to vibration
that is causing voltage to drop on that analogiue line.


You're conflating redundancy in sensors vs. a wire used to send a
command.

YouLll notice that the SpaceX documents speak of "command". A command
sent as data would have checksums etc to valiate it, and likely sent on
at least 2 data links across modules.


You're assuming that there is some sort of data link here. That is
almost certainly not the case because this system needs to be as simple
as possible. One GTFO "command" is all we need, so a discrete command
line is what they would use.

Everything else that followed the above was based on these false
premises, so I deleted it all.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Bought Senators claim 'commercial crew sucks' Anonymous[_14_] Policy 7 March 14th 12 01:19 AM
Commercial Crew: The Perception Problem Matt Wiser[_2_] History 9 September 29th 10 01:06 PM
Commercial Crew Flight by 2015? Space Cadet[_1_] Policy 2 May 14th 10 11:54 PM
Commercial launch of cargo but not crew [email protected] Space Station 1 August 15th 09 09:40 AM
NASA ESTABLISHES COMMERCIAL CREW/CARGO PROJECT OFFICE Jacques van Oene Space Shuttle 4 November 9th 05 07:58 PM


All times are GMT +1. The time now is 07:43 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright 2004-2020 SpaceBanter.com.
The comments are property of their posters.