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  #1  
Old August 21st 18, 01:14 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Default Load and Go a Go

I don't think I mention this before, but it looks like NASA has
approved the SpaceX 'load and go' fueling plan for manned vehicles.
All they'll have to do is complete the handful of flights (in 'manned'
configuration, but presumably without people) required to 'man-rate' a
system.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden
  #2  
Old August 21st 18, 01:19 AM posted to sci.space.policy
Alain Fournier[_3_]
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Default Load and Go a Go

On Aug/20/2018 at 8:14 PM, Fred J. McCall wrote :
I don't think I mention this before, but it looks like NASA has
approved the SpaceX 'load and go' fueling plan for manned vehicles.
All they'll have to do is complete the handful of flights (in 'manned'
configuration, but presumably without people) required to 'man-rate' a
system.


Is it possible for SpaceX to launch satellites or do something useful
(maybe bring cargo to ISS) while in 'manned configuration', but without
people aboard?


Alain Fournier
  #3  
Old August 21st 18, 04:31 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Alain Fournier wrote on Mon, 20 Aug 2018
20:19:03 -0400:

On Aug/20/2018 at 8:14 PM, Fred J. McCall wrote :
I don't think I mention this before, but it looks like NASA has
approved the SpaceX 'load and go' fueling plan for manned vehicles.
All they'll have to do is complete the handful of flights (in 'manned'
configuration, but presumably without people) required to 'man-rate' a
system.


Is it possible for SpaceX to launch satellites or do something useful
(maybe bring cargo to ISS) while in 'manned configuration', but without
people aboard?


I assume so. Dragon V2 is supposed to be able to carry cargo rather
than people and I would think just removing seats and such to switch
to a cargo configuration wouldn't invalidate any 'test' flights for
man rating of Falcon 9/Dragon V2 system configuration.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden
  #4  
Old August 21st 18, 04:46 AM posted to sci.space.policy
David Spain
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Default Load and Go a Go

On 8/20/2018 8:14 PM, Fred J. McCall wrote:
I don't think I mention this before, but it looks like NASA has
approved the SpaceX 'load and go' fueling plan for manned vehicles.
All they'll have to do is complete the handful of flights (in 'manned'
configuration, but presumably without people) required to 'man-rate' a
system.



By 'load and go' I presume you mean loading people before fueling.
This is good news. The SpaceX plan seemed far less risky to me.
The only people around the rocket after fuel and oxidizer are loaded are
the folks in the Dragon V2, capable of getting away in a hurry. No one
else need be near it.

I presume it was the other way round in the older days because the
complexity of the fueling operation of the three-stage Saturn and the
variety of propellants used just made it to unwieldy to put crew aboard
before fueling and awaiting the requisite multiple hours under risk
while all that fueling took place. Let's see we had, LOX, LH2, RP-1(?),
not to mention the slush O2 tanks in the Service Module, and the
hypergolics and the fuel in the LEM. I can understand wanting to
minimize crew time on that stack.

Dave

  #5  
Old August 21st 18, 10:06 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Default Load and Go a Go

JF Mezei wrote on Mon, 20 Aug 2018
23:43:50 -0400:

On 2018-08-20 23:31, Fred J. McCall wrote:

I assume so. Dragon V2 is supposed to be able to carry cargo rather
than people and I would think just removing seats and such to switch
to a cargo configuration wouldn't invalidate any 'test' flights for
man rating of Falcon 9/Dragon V2 system configuration.


Won't a cargo variant of Dragon 2 fly first, and test the docking
software and hardware (it goes to a PMA, right, instead of CBM ?)


I don't recall them saying that first test would be with a cargo
variant, but it certainly could be.


In terms of the crewed version, wouldn't NASA want to put instrumented
dummies in there to record G forces, vibration, noise and atmosphere
pressure etc? (especially for the landing).


Unnecessary. Any dummies will get the same g forces as the rest of
the capsule. Even if the capsule didn't have its own g sensor (it
does), you could figure out g forces just by tracking it and looking
at deceleration rates. WHATEVER it does on landing would have to be
gentler than Soyuz. Older versions of Soyuz hit 12+ g on the way
down. Aerodynamic studies indicate that Dragon V2 will peak under
3.5g.


If the mass on the crewed version will be significantly different,
perhaps NASA wants to emulate that mass as closely as possible for
liftoff, manoeuvering in space, re-entry and slashdown.


Things that don't matter just don't matter. That doesn't matter.


(Carrying cargo of same mass as what the crew would have would be
possible though).


CG would still presumably be different. You seem to be trying to make
the argument that the only way to man rate a system is to fly people
on it, which seems just a bit circular. And if you DO have to go that
route, just how many people do you fly, since Dragon V2 can carry up
to 7 people?


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #6  
Old August 21st 18, 10:09 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Default Load and Go a Go

David Spain wrote on Mon, 20 Aug 2018 23:46:42
-0400:


By 'load and go' I presume you mean loading people before fueling.


Yep.


This is good news. The SpaceX plan seemed far less risky to me.


That's the eventual conclusion NASA came to, after investigating the
crap out of structure, ground procedures, etc.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden
  #9  
Old August 22nd 18, 12:51 AM posted to sci.space.policy
Jeff Findley[_6_]
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Default Load and Go a Go

In article ,
says...

On 2018-08-21 05:06, Fred J. McCall wrote:

Unnecessary. Any dummies will get the same g forces as the rest of
the capsule.


Do the seats/couches provide any G force reduction? Or are they "fixed"
and protect the occupants by being perfectly moulded like on Soyuz?


Seats don't reduce G forces. If we could do that, we'd have literal
anti-gravity beds here on earth so that patients in the hospital would
never get bedsores.

If there is some suspension provided by the seats to cushion landing,
you will want to have human-like mass on the seats with G force sensors.


Like Fred said, dummies. Specifically, instrumented "crash test"
dummies. They're used in the aerospace industry as well as the
automotive industry. They mimic the mass, strength, and etc of a human
and are instrumented to measure the accelerations at various parts of
the dummy's body. They're literally "off the shelf" items.

Things that don't matter just don't matter. That doesn't matter.


Ensuring that the capsule re-enters correctly when the mass it carries
is that of a crew would be important. A different mass means different F
forces during re-entry interface and during the actual landing.


Again, dummies.

And it would presumably also test the software when firing thrusters to
ensure it can handle the mass of the crew.


Yep, dummies. Jebus this is getting repetitive.

CG would still presumably be different. You seem to be trying to make
the argument that the only way to man rate a system is to fly people
on it,


I said dummies, not people.


Then WTF are we talking about?!?!?

Jeff
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These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #10  
Old August 22nd 18, 12:56 AM posted to sci.space.policy
Jeff Findley[_6_]
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Default Load and Go a Go

In article ,
says...

On 2018-08-21 06:32, Jeff Findley wrote:

Yes. The rocket doesn't care what payload is on top when you're going
through pre-launch procedures like fueling.


In a cargo, you need not provide for emergency egress since the cargo is
unlikely to get scared and want to exit ASAP if things go wrong.


You test "emergency egress" on the pad, when the rocket isn't loaded
with fuel.

I assume that a bridge from tower to capsule will remain for some time
during fueling to allow such egress. (or would SpaceX just train
astronauts to press the big red button for capsule jettison and do away
for emergency egress ?


For fueling, the escape system will be armed. If something really
"bad" happens to the launch vehicle, it will fire automatically. Human
reaction time is too slow to save the crew if the vehicle bursts a fuel
and/or oxidizer tank.

Will SpaceX provide emergency egress joy ride in a basket down a long
rope like for Shuttle?


Yes. It has to move up higher on the fixed structure, but it will be
there. Not sure how that fits in with the escape system, but SpaceX and
NASA have surely thought of how to handle that.

I take it NASA will want astronauts all tucked in and hatches closed
before fueling begins, or would it allow that operation to be done while
fueling is happening?


When fueling Falcon 9, the astros are in their seats, the abort system
is armed, and there are *no* ground crews around.

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.
 




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