VSS Enterprise completes first flight under its carrieraircraft

On Tue, 30 Mar 2010 07:39:44 -0400, Jeff Findley wrote:

"Peter Stickney" wrote in message
...
Better not ever got on an airliner, Pat, you don't get ejection seats
or parachutes there, either.

The FAA isn't going to certificate White Knight unless it can keep the
passengers alive and descend to a survivable level after
depressurization.

The FAA hasn't yet certified *any* suborbital vehicles for passenger
carrying service. What they will, or won't, do is a bit up in the air,
so to speak.

Jeff,
White Knight isn't the suborbital vehicle. It's the carrier aircraft.
If it's going to be carrying people for money, it _will_ have to be certificated.
And it will have to provide acceptable standards of airworthiness and safety.



--
Pete Stickney
Failure is not an option
It comes bundled with the system

"Jeff Findley" writes:

"Peter Stickney" wrote in message
...
Better not ever got on an airliner, Pat, you don't get ejection seats or
parachutes there, either.

The FAA isn't going to certificate White Knight unless it can keep the
passengers alive and descend to a survivable level after depressurization.

The FAA hasn't yet certified *any* suborbital vehicles for passenger
carrying service. What they will, or won't, do is a bit up in the air, so
to speak.

Jeff

I know that the cabins for both WK1 and SS1 were identical, it was a major
cost savings for Scaled to do it that way.

Assuming the same is true for WK2 and SS2, if they certify one there shouldn't
be any major reason not to be able to certify the other.

?

Dave

"Peter Stickney" wrote in message
...
On Tue, 30 Mar 2010 07:39:44 -0400, Jeff Findley wrote:

"Peter Stickney" wrote in message
...
Better not ever got on an airliner, Pat, you don't get ejection seats
or parachutes there, either.

The FAA isn't going to certificate White Knight unless it can keep the
passengers alive and descend to a survivable level after
depressurization.

The FAA hasn't yet certified *any* suborbital vehicles for passenger
carrying service. What they will, or won't, do is a bit up in the air,
so to speak.

White Knight isn't the suborbital vehicle. It's the carrier aircraft.
If it's going to be carrying people for money, it _will_ have to be
certificated.
And it will have to provide acceptable standards of airworthiness and
safety.

True, I confused what was being talked about. Wikipedia says WK2 will fly
at 60k feet (same service ceiling as the Concorde), so if no pressure suits
was good enough for Concorde, it should be good enough for WK2.

Now SS2 is a whole other kettle of fish... As a passenger, in SS2, I'd want
at least a pressure suit, given the Soyuz crew that died from
depressurization.

Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon

On 3/30/2010 4:31 AM, Peter Stickney wrote:

The FAA hasn't yet certified *any* suborbital vehicles for passenger
carrying service. What they will, or won't, do is a bit up in the air,
so to speak.

Jeff,
White Knight isn't the suborbital vehicle. It's the carrier aircraft.
If it's going to be carrying people for money, it _will_ have to be certificated.
And it will have to provide acceptable standards of airworthiness and safety.

Now, here comes a interesting question: when the two aircraft are joined
together in flight prior to launch, is Space Ship 2 considered a
seperate aircraft or part of White Knight 2 as far as FAA rules go?

Pat

"Pat Flannery" wrote in message
dakotatelephone...
On 3/30/2010 5:28 AM, Jeff Findley wrote:
Now SS2 is a whole other kettle of fish... As a passenger, in SS2, I'd
want
at least a pressure suit, given the Soyuz crew that died from
depressurization.

There's a way around the bends problem if depressurization occurs at
near-space altitudes, but it would create another problem while fixing
that one.
If Space Ship 2 used a pure oxygen environment and the crew and passengers
pre-breathed pure oxygen for a hour or two prior to the flight, it would
wash the nitrogen out of their blood and they wouldn't get the bends if
they experienced depressurization.

At some low pressure, doesn't the oxygen in the blood (and CO2) also start
to boil? Somewhere someplace we discussed exposure to vaccuum of an entire
human body and how long it would take to die. I didn't think it was all
that long. Here's a reference:

http://imagine.gsfc.nasa.gov/docs/as...rs/970603.html

From above:

After perhaps one or two minutes, you're dying.
The limits are not really known.

So unless SS2 can descend to something like 60k feet in less than a minute
after a complete depressurization event, I think the crew and passengers
would be toast. I suppose that one could argue that on a craft like this, a
complete depressurization event would also be a structural failure whoch
would dooom the crew anyway. The problem then would be to mitigate the
effects of a partial depressurization.

Unfortunately, this now returns the Apollo 1 fire problem.

So you solve it in a similar way that Apollo Block II capsules did. You
launch with 60% O2 and 40% N2 in order to mitigate the fire problem. This
results in a breathable atmosphere as the capsule is depressurized down to 5
psi. Inside the suits they still used pure O2 to prevent the bends.

Would a oxygen-helium atmosphere work? That would make fire impossible,
but does helium go into solution in the blood like nitrogen does?
Frankly, they really should have pressure suits on if this thing is going
to be anywhere near safe by FAA passenger standards.

Helium might be a better choice than nitrogen if you're trying to avoid O2
masks to prevent the bends in case of a cabin (partial) depressurization.

Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon

On 3/30/2010 5:28 AM, Jeff Findley wrote:
Now SS2 is a whole other kettle of fish... As a passenger, in SS2, I'd want
at least a pressure suit, given the Soyuz crew that died from
depressurization.

There's a way around the bends problem if depressurization occurs at
near-space altitudes, but it would create another problem while fixing
that one.
If Space Ship 2 used a pure oxygen environment and the crew and
passengers pre-breathed pure oxygen for a hour or two prior to the
flight, it would wash the nitrogen out of their blood and they wouldn't
get the bends if they experienced depressurization.
Unfortunately, this now returns the Apollo 1 fire problem.
Would a oxygen-helium atmosphere work? That would make fire impossible,
but does helium go into solution in the blood like nitrogen does?
Frankly, they really should have pressure suits on if this thing is
going to be anywhere near safe by FAA passenger standards.

Pat

On 3/30/2010 10:21 AM, Jeff Findley wrote:
At some low pressure, doesn't the oxygen in the blood (and CO2) also start
to boil? Somewhere someplace we discussed exposure to vaccuum of an entire
human body and how long it would take to die. I didn't think it was all
that long. Here's a reference:

http://imagine.gsfc.nasa.gov/docs/as...rs/970603.html

From above:

After perhaps one or two minutes, you're dying.
The limits are not really known.

Although the crew may die after that amount of time, the real problem is
the fact that they will be unconscious after around twenty seconds, and
at that point won't be able to control the spacecraft, which will
probably break up as it comes down with no piloting before anyone
recovers at a lower altitude.


So unless SS2 can descend to something like 60k feet in less than a minute
after a complete depressurization event, I think the crew and passengers
would be toast. I suppose that one could argue that on a craft like this, a
complete depressurization event would also be a structural failure whoch
would dooom the crew anyway.

Given the small size of the cabin, it wouldn't take that big of a hole
to let the air out in fairly quick order. The pressure equalization
valve that opened on Soyuz 11 could apparently be blocked with a finger,
yet the reentry module depressurized completely in 112 seconds after it
was opened.
Here's a description of the incident from "Challenge to Apollo":

'Through the following weeks, an analysis of the Mir on-board memory
device showed that at the moment of separation of the living compartment
from the descent apparatus, at an altitude of more than 150 kilometers,
the pressure in the descent apparatus dropped in the course of thirty to
forty seconds to a near vacuum. The rate of the pressure drop
corresponded to the respiratory system's valve opening. The conclusion
was obvious: at the moment of separation of the two modules, the valve
had prematurely opened. More difficult was determining exactly why it
had been jarred open. Engineers carried out dozens of experiments
simulating various loads on the suspect valve, but no one particular
cause stood out. Only when all types of deviations from normal
parameters were introduced simultaneously did the valve
fail. Based on the Keldysh commission's analysis of voice tapes and
telemetry, as well as Kamanin's own diary entries, it was, however,
possible to reconstruct the sequence of events that led to the tragedy.
It seems that the reentry burn was on time and completely successful.
Subsequently, at the very moment that the Soyuz spacecraft separated
into its three component modules, also on time, twelve explosive bolts
used for separation produced an overload, displacing a ball joint from
its seating. This accidentally jerked open the ventilation valve, which
was to have opened only after landing: suddenly, there was a direct
passage from the crew compartment to the vacuum outside. The crew
immediately noticed the drop in pressure inside the capsule:
Dobrovolskiy quickly unfastened his seat belts and rushed to the frontal
hatch, thinking that the problem was the faulty hatch seal from the
undocking incident. The hatch was completely secure, yet the pressure
continued to drop in a whistle that continued to get louder. In fact,
the sound of the air whistling out of the spacecraft was coming not only
from the suspect valve but also from on-board radio transmitters and
receivers, making it difficult to isolate the true source. At this
point,Volkov and Patsayev unfastened their belts and
switched off all communications systems to find the source of the
whistling; the sound was apparently coming from a point under
Dobrovolskiy's seat - the ventilation valve.
Dobrovolskiy and Patsayev attempted to manually close the valve, but the
time was just too short. Both fell back into their seats, with
Dobrovolskiy having time to refasten his belts in a hurried move, which
left them tangled.
The speed of the pressure loss in the capsule was incredibly swift. Just
four seconds after the ventilation valve failure, Dobrovolskiy's
breathing rate shot up from sixteen(normal) to forty-eight per minute.
After the beginning of pressure loss, the cosmonauts lost the
capacity to work in ten to fifteen seconds and were dead in forty-eight
to forty-nine seconds. They were apparently "in agony" three to five
seconds after separation until about
twenty to thirty seconds before death. The pressure in the capsule
dropped from a normal level of 920 millimeters to zero in a matter of
112 seconds. As one Russian journalist later put it, the cosmonauts
"passed away fully aware of the tragic consequences of what
had happened". Both Kamanin and Mishin seemed to believe that the crew
could have prevented their deaths by simply blocking the suspect "hole."
In an interview in 1990, Mishin added: "They could hear the hiss of
escaping air. They could have put a finger over the hole and that would
have done it." Some believed that the crew had not been properly trained
in the operation of the valve, which was to be operated only after Soyuz
landing.
The technical documentation on the valve stipulated: "If in case of a
water landing, the hatch does not open due to rough seas, or rescue
teams are late in coming for over an hour,the cosmonauts may open the
valve." '



The problem then would be to mitigate the
effects of a partial depressurization.

Unfortunately, this now returns the Apollo 1 fire problem.

So you solve it in a similar way that Apollo Block II capsules did. You
launch with 60% O2 and 40% N2 in order to mitigate the fire problem. This
results in a breathable atmosphere as the capsule is depressurized down to 5
psi. Inside the suits they still used pure O2 to prevent the bends.

They still seem undecided about pressure suits for the passengers and
crew: http://www.thespacereview.com/article/717/1

'In the animation depicting the flight, passengers are seen wearing
full-body suits with helmets (whose visors are mirrored so we never see
their faces). Virgin Galactic president Will Whitehorn said, though,
that the company hasn’t made a decision whether or not passengers will
wear pressure suits—which typically have been bulky and expensive—or if
they will be able to fly in a shirtsleeve environment like that on SS1.
“We don’t believe that [cabin] depressurization is an issue that we have
to deal with,” he said. “However, it may well be that there is an
advantage of having a passive pressure suit anyway” that would protect
passengers from injuries that might be incurred from bumping into
things—or each other—in zero-g. He added that they are currently looking
at three different suits and will make a final decision on what suit to
use, if any, during the flight test program.'

Never underestimate the ability of people to incrementally talk
themselves into a really dumb idea over a period of years if it saves
them time and money.
Ideas which at the beginning of the program would seem completely crazy
may seem perfectly rational by the time it's implemented, and I can
certainly see them talking themselves into the concept that they don't
need pressure suits, on the grounds that:
1.) The thing is as safe as an airliner, and airliners don't use
pressure suits.
2.) If something does go wrong, it will probably be so severe that
pressure suits wouldn't save anyone anyway.
....without realizing that those two arguments aren't exactly compatible
- as number one suggests you can predict anything that can go wrong and
design it out, and number two suggests you can predict things that may
still go wrong, and they are all inevitably fatal.
In reality, unexpected events are what lead to number one being false,
and number two not always being true.

I thought of the atmosphere shift also, but the speed of the ascent
under rocket power will mean that the pressure change from flight level
pressure under the White Knight (probably around 8,000-10,000 feet) to 5
psi will occur so fast that it might rupture the occupant's eardrums.
If you could have them breathe pure oxygen at 5 psi right from the
moment of boarding the spacecraft on the ground it would work, as you
could slowly replace the surface air with the O2 before lift-off, and
have them remove their oxygen pre-breathers once they were in a pure low
pressure O2 atmosphere.

Would a oxygen-helium atmosphere work? That would make fire impossible,
but does helium go into solution in the blood like nitrogen does?
Frankly, they really should have pressure suits on if this thing is going
to be anywhere near safe by FAA passenger standards.

Helium might be a better choice than nitrogen if you're trying to avoid O2
masks to prevent the bends in case of a cabin (partial) depressurization.

They would sound odd, but they would be safer.

Pat

"OM" wrote in message
...
On Tue, 30 Mar 2010 21:43:06 -0800, Pat Flannery
wrote:

Never underestimate the ability of people to incrementally talk
themselves into a really dumb idea over a period of years if it saves
them time and money.

...Something so damn obvious that I never bothered to coin it as an
OM's Law, and yet so many people fail to grasp the significance of
this.

It's so true, and I like Pat's wording. Maybe we should call this Pat
Flannery's Law? ;-)

Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon

On 3/31/2010 6:03 AM, Jeff Findley wrote:

Never underestimate the ability of people to incrementally talk
themselves into a really dumb idea over a period of years if it saves
them time and money.

...Something so damn obvious that I never bothered to coin it as an
OM's Law, and yet so many people fail to grasp the significance of
this.

It's so true, and I like Pat's wording. Maybe we should call this Pat
Flannery's Law?

I kind of liked that one myself to tell you the truth. ;-)

Pat

Jeff Findley wrote:
"OM" wrote in message
...
On Tue, 30 Mar 2010 21:43:06 -0800, Pat Flannery
wrote:

Never underestimate the ability of people to incrementally talk
themselves into a really dumb idea over a period of years if it saves
them time and money.
...Something so damn obvious that I never bothered to coin it as an
OM's Law, and yet so many people fail to grasp the significance of
this.

It's so true, and I like Pat's wording. Maybe we should call this Pat
Flannery's Law? ;-)

Bah, Demotivators worded it even better.

http://despair.com/meetings.html

(This one hangs on the wall in the JSC MMT meeting room, BTW.)