Shuttle Flights Halted

"The space shuttle fleet is grounded until technicians
find and fix a vexing problem with engine cutoff (ECO)
sensors--a component that NASA now realizes has
likely never worked throughout the 26-year history of
the shuttle program."

See:

http://www.aviationweek.com/aw/gener...ights%20Halted

I wonder how many other systems on the shuttle have,
without NASA knowing it, never been functional.

wrote:
"The space shuttle fleet is grounded until technicians
find and fix a vexing problem with engine cutoff (ECO)
sensors--a component that NASA now realizes has
likely never worked throughout the 26-year history of
the shuttle program."

See:

http://www.aviationweek.com/aw/gener...ights%20Halted

I wonder how many other systems on the shuttle have,
without NASA knowing it, never been functional.

If there were a leak in the external tank, then the mass of the vehicle
would be falling faster than it should. This would mean that the vehicle
would be accelerating faster than predicted, which is something that
should be detectable.

Sylvia.

On Dec 22, 12:32*am, Sylvia Else wrote:
wrote:
"The space shuttle fleet is grounded until technicians
find and fix a vexing problem with engine cutoff (ECO)
sensors--a component that NASA now realizes has
likely never worked throughout the 26-year history of
the shuttle program."

See:

http://www.aviationweek.com/aw/gener...p?channel=awst....

I wonder how many other systems on the shuttle have,
without NASA knowing it, never been functional.

If there were a leak in the external tank, then the mass of the vehicle
would be falling faster than it should. This would mean that the vehicle
would be accelerating faster than predicted, which is something that
should be detectable.

Sylvia.

Yes, there are generally multiple sources for any
type of information. It seems that the Shuttle--
and perhaps space systems, in general, are
unnecessarily overly complex, with too much
dependency on any one item.

In our F8F Bearcat squadron (1947), we had
24 aircraft and no spares. On frequent occasions,
we would line up all 24 on the mat at North Island
and take off in a "scouting line." With a left turn
over Pt. Loma, we would have 24 aircraft in
formation of six divisions of 4 aircraft each. I
can never recall not being able to count on all
24 aircraft when we wanted to use this procedure.
Sure, the aircraft were much simpler, and we
sometimes flew without all systems operative.
But that is my point.

A space transport system should be far more
robust than current launch systems. A big step
in this direction is to design the operations and
system to avoid hand-wringing crucial situations
--such as engine-out abort on takeoff. IMO,
this is a basic, step-1 requirement that had
generally been ignored in all launch systems
built to date.

With GPS and other on-board capabilities, I
view controllers on the ground as an extra--
probably valuable--additional capability, but
not a necessity. Horizontal takeoff is not
only an advantage for engine-out abort, but
it also makes range safety somewhat less
critical, because the space transport can be
clear of the beach and out to sea somewhat
before gaining a lot of altitude high over the
launch complex. It seems to me that a lot
or problems can be avoided by getting away
from our current launch-vehicle mindset.

Len

On Dec 22, 12:21 pm, Len wrote:

1. A space transport system should be far more
robust than current launch systems. A big step
in this direction is to design the operations and
system to avoid hand-wringing crucial situations
--such as engine-out abort on takeoff. IMO,
this is a basic, step-1 requirement that had
generally been ignored in all launch systems
built to date.

2, With GPS and other on-board capabilities, I
view controllers on the ground as an extra--
probably valuable--additional capability, but
not a necessity.

3. Horizontal takeoff is not
only an advantage for engine-out abort, but
it also makes range safety somewhat less
critical, because the space transport can be
clear of the beach and out to sea somewhat
before gaining a lot of altitude high over the
launch complex. It seems to me that a lot
or problems can be avoided by getting away
from our current launch-vehicle mindset.

Len

1. you got the money for a more 'robust" system. Nor does anyone
else

2. Launch vehicles are not "controlled" from the ground. Once they
launch, they are autonomous, except for range safety. The launch
control centers have no real role after T-0 other than monitoring
telemetry. They have no capability to alter anything on a launch
vehicle. This applies to all US launch vehicles. Same goes for the
shuttle, mission control just advises the crew

3. Horizontal takeoff require aerosurfaces which are useless in the
latter part of flight and actually reduce performance

wrote:
On Dec 22, 12:21 pm, Len wrote:

1. A space transport system should be far more
robust than current launch systems. A big step
in this direction is to design the operations and
system to avoid hand-wringing crucial situations
--such as engine-out abort on takeoff. IMO,
this is a basic, step-1 requirement that had
generally been ignored in all launch systems
built to date.

2, With GPS and other on-board capabilities, I
view controllers on the ground as an extra--
probably valuable--additional capability, but
not a necessity.

3. Horizontal takeoff is not
only an advantage for engine-out abort, but
it also makes range safety somewhat less
critical, because the space transport can be
clear of the beach and out to sea somewhat
before gaining a lot of altitude high over the
launch complex. It seems to me that a lot
or problems can be avoided by getting away
from our current launch-vehicle mindset.

Len

1. you got the money for a more 'robust" system. Nor does anyone
else

2. Launch vehicles are not "controlled" from the ground. Once they
launch, they are autonomous, except for range safety. The launch
control centers have no real role after T-0 other than monitoring
telemetry. They have no capability to alter anything on a launch
vehicle. This applies to all US launch vehicles. Same goes for the
shuttle, mission control just advises the crew

3. Horizontal takeoff require aerosurfaces which are useless in the
latter part of flight and actually reduce performance

I do believe that is the paradigm Len is trying to change, Jim.

On Dec 22, 1:18*pm, wrote:
On Dec 22, 12:21 pm, Len wrote:

1. *A space transport system should be far more
robust than current launch systems. *A big step
in this direction is to design the operations and
system to avoid hand-wringing crucial situations
--such as engine-out abort on takeoff. *IMO,
this is a basic, step-1 requirement that had
generally been ignored in all launch systems
built to date.

2, *With GPS and other on-board capabilities, I
view controllers on the ground as an extra--
probably valuable--additional capability, but
not a necessity.

3. *Horizontal takeoff is not

only an advantage for engine-out abort, but
it also makes range safety somewhat less
critical, because the space transport can be
clear of the beach and out to sea somewhat
before gaining a lot of altitude high over the
launch complex. *It seems to me that a lot
or problems can be avoided by getting away
from our current launch-vehicle mindset.

Len

1. *you got the money for a more 'robust" system. *Nor does anyone
else

Maybe. Time will tell.

2. *Launch vehicles are not "controlled" from the ground. *Once they
launch, they are autonomous, except for range safety. * The launch
control centers have no real role after T-0 other than monitoring
telemetry. *They have no capability to alter anything on a launch
vehicle. This applies to all US launch vehicles. *Same goes for the
shuttle, mission control just advises the crew

I'm not against advice from the ground. I
just like to avoid having the tail wag the dog.
When we start flying thousands of flights per
year, an FAA space traffic control and advisory
service will probably be well justified. This might
end up being a combined FAA/NASA Houston
operation.

3. *Horizontal takeoff require aerosurfaces which are useless in the
latter part of flight and actually reduce performance

A system designer should design to the total
job and the total trajectory. The aero surfaces
of the carrier stage are useful during the whole
initial boost, staging and recovery phases. The
carrier and its 1000 m^2 wing (without the orbiter)
can actually pull 2g's at the mach 2 / 40 km staging
point where dynamic pressure is only 750 Pa.

The orbiter, conversely is relatively unaffected by
the relatively thin air.

If it is necessary to abort before staging, the
carrier can recover with the orbiter, if orbiter
propellants are jettisoned. If abort is necessary
just after staging, then the orbiter (after jettisoning
propellants, if appropriate) can glide back to the
launch-site runway for an unpowered landing.
The carrier always makes an unpowered landing,
with or without the empty orbiter on board.

Since the carrier is like a huge ultralight on
landing, we will probably have special runway
vehicles grab each wing tip if conditions are
somewhat gusty. Landing speed is unusually low.

The aero surfaces of the orbiter (in our "kite-plane"
approach) are unusually light and perform the
reentry phase and landing phase in a manner
that quite justifies the mass of the orbiter
aero surfaces. My calculations indicate that
a proper allowance for landing with vertical
thrust would require a greater mass than the
orbiter aero surfaces. Our TPS is practical,
based upon low planform loading and relatively
low reentry temperatures; overall TPS mass is
quite reasonable in spite of the 250 m^2
lower surface of the orbiter wing. All transparent
areas are in the lee. The orbiter upper surfaces
do not require TPS. The orbiter is aerodynamically
stable though-out reentry.

Len

I still believe a 2 stage vehicle would be best and theres rumors of a
black program that did just that.

stage one a big hugger airliner refuled repeatedly to release
altitude. this way all the fuel doesnt have to be onboard at liftoff.

stage 2 a small manned winged shuttle for people only. with release
near space

rocket booster after reaching cruising altitude of say 100,000 feet.

wings add cross range landing or bail out capabilities. could also be
used for ISS escape in emergencies.

a variant could launch from a expendable make it carry say 3 people

On Dec 22, 5:20*pm, " wrote:
I still believe a 2 stage vehicle would be best and theres rumors of a
black program that did just that.

stage one a big hugger airliner refuled repeatedly to release
altitude. this way all the fuel doesnt have to be onboard at liftoff.

Lift is not necessarily the problem, power is
generally the problem. Airbreathing doesn't
have the potential for getting to really high altitude
at subsonic speeds; supersonic and hypersonic
propulsion can get to somewhat higher altitudes,
but with very bad side effects. Rocket power and
big wings work well. Airliners and bombers don't
seem to be the good candidates that I once thought
they might be.

I believe Andrews Aerospace looked at air
liquifaction schemes to reduce wing loading
and landing gear problems at takeoff. This is
an interesting idea with considerable merit.
However, either a big wing or a ballistic
thrust-to-weight become necessary, once the
system reaches modest altitudes.

Our approach relies on a ground cart--even
for a TSTO--along with an abnormally large
wing, plus rocket power (airbreathing engines
are sized for landing). This patent-pending,
"kite-plane" approach is inefficient from the
delta-vee point of view because of severe
limits on peak dynamic pressure; however,
it seems to be a real winner from other aspects.
As pointed out in some of our earlier Space
Access briefings, the delta-vee inefficiency
is of little consequence, since the propellants
are soon gone, the propellants are cheap, and
the tankage is light. The ground cart, relieving
load from careful propellant placement and
large wing minimize the potentially bad effects
of higher mass at takeoff.

Len

stage 2 a small manned winged shuttle for people only. with release
near space

*rocket booster after reaching cruising altitude of say 100,000 feet.

wings add cross range landing or bail out capabilities. could also be
used for ISS escape in emergencies.

a variant could launch from a expendable make it carry say 3 people

wrote:
I still believe a 2 stage vehicle would be best and theres rumors of a
black program that did just that.

stage one a big hugger airliner refuled repeatedly to release
altitude. this way all the fuel doesnt have to be onboard at liftoff.


Refuelled repeatedly? Just how long are you allowing for the launch?

Sylvia.

Sylvia Else writes:

wrote:
I still believe a 2 stage vehicle would be best and theres rumors of a
black program that did just that.

stage one a big hugger airliner refuled repeatedly to release
altitude. this way all the fuel doesnt have to be onboard at liftoff.

Refuelled repeatedly? Just how long are you allowing for the launch?

I'm just envisioning the process of hypersonic refeuling
operations, and it strikes me as just about the funniest thing one
could possibly think of attempting with low-altitude spacecraft.

--
Joseph Nebus
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