faulty fuel sensor - oh puleeze

[Granite]

Discovery can't take off because of a bad fuel sensor ? Are they kidding us
? The crew is already strapped in, number one for departure, cocked and
loaded. We just put gas in the thing. I saw the line guys top the tanks
earlier in the day. Stick the tank, placard the gas gauge inop and let's go
haul the mail ! Now it takes three or four days to replace it ? They need
to find a new A&P, preferably non-union. We are never going to get
commercial space travel at this rate. I'm sure the FAA is to blame too ...
somehow.

[tony roberts]

The tanks contain hydrogen and oxygen. A combination of the two power it.
If it runs out of either, it can blow, or overspool the engine - either
would be fatal. So it needs accurate fuel sensors - unless you want to
fly it. Crew safety is paramount - and right now it's compromised.

Tony
C-GICE

In article >,
"Granite" > wrote:

> Discovery can't take off because of a bad fuel sensor ? Are they kidding us
> ? The crew is already strapped in, number one for departure, cocked and
> loaded. We just put gas in the thing. I saw the line guys top the tanks
> earlier in the day. Stick the tank, placard the gas gauge inop and let's go
> haul the mail ! Now it takes three or four days to replace it ? They need
> to find a new A&P, preferably non-union. We are never going to get
> commercial space travel at this rate. I'm sure the FAA is to blame too ...
> somehow.




--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE

[Peter Duniho]

"tony roberts" > wrote in message
news:nospam-33EADD.23165714072005@shawnews...
> [...] Crew safety is paramount - and right now it's compromised.

Surely the post to which you replied wasn't meant to be serious.

[S.]

"Granite" > wrote in message
.. .
> Discovery can't take off because of a bad fuel sensor ? Are they kidding
> us
> ? The crew is already strapped in, number one for departure, cocked and
> loaded. We just put gas in the thing. I saw the line guys top the tanks
> earlier in the day. Stick the tank, placard the gas gauge inop and let's
> go
> haul the mail ! Now it takes three or four days to replace it ? They
> need
> to find a new A&P, preferably non-union. We are never going to get
> commercial space travel at this rate. I'm sure the FAA is to blame too
> ...
> somehow.
>

Depends. It was reported here, UK, that 1 of 4 sensors failed.

Why so much redundancy ? ; the cost of scrubbing the launch must have been
enormous.

[Dave S]

S. wrote:

>
> Why so much redundancy ? ; the cost of scrubbing the launch must have been
> enormous.

As is the percieved cost of another failure. Nobody wants to be the one
who says "Go" and then something bad happens.

Dave

[Denny]

As a general rule among bureaucrats, you can never be faulted for
saying, NO....

Now, having made this insightful contribution, I wll say that the
perception among NASA is that losing another crew will be the end of
NASA as we/they know it... No manager in NASA is going to voluntarily
be the fall guy who says, "Ahhh what the hell, launch it!"......
Understandable...

A perception problem was created by NASA when they worked hard for
decades to foster the belief that NASA is so good that launching to
orbit is just routine... Sitting on top of a half million pounds of
explosives, then igniting a 'controlled explosion' in a container just
below the tanks of explosives, is never going to be routine... Nor is
slamming into the atmosphere at Mach 17.5 and having the leading edges
instantly hit 3,000 F...

But, I would much rather be an astronaut who depends upon NASA
engineers to launch his tender body, than have been a cosmonaut under
the USSR's space program... Look up the available footage of some of
their more spectacular failures...

denny

[Nathan Young]

On Thu, 14 Jul 2005 10:57:50 GMT, Dave S >
wrote:

>
>
>S. wrote:
>
>>
>> Why so much redundancy ? ; the cost of scrubbing the launch must have been
>> enormous.
>
>As is the percieved cost of another failure. Nobody wants to be the one
>who says "Go" and then something bad happens.

Exactly. If there is another shuttle disaster, the program may not
ever recover.

[[email protected]]

"S." > wrote:
> the cost of scrubbing the launch must have been
> enormous.

$600K, according to the news.

[Peter R.]

"S." > wrote:

> the cost of scrubbing the launch must have been enormous.

The cost of launching and potentially losing the shuttle would have been
much, much greater, both in terms of dollars and a country's lost
confidence in the space program.

--
Peter
























----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

[Dave S]

Denny wrote:

>
> But, I would much rather be an astronaut who depends upon NASA
> engineers to launch his tender body, than have been a cosmonaut under
> the USSR's space program... Look up the available footage of some of
> their more spectacular failures...
>
> denny
>
I want to say they have a body count of over 100 with regards to their
early space program.

Dave

[Maule Driver]

Legitimate question but a strange place to pose it...here in the land of
multiple engines, MELs, backup vacs, redundant electrical systems,
multiple 430s, GPS, VOR, ADF, and Loran (why not keep all of it?)

Perhaps I'm thinking of rec.aviation.ifr...

>
> Depends. It was reported here, UK, that 1 of 4 sensors failed.
>
> Why so much redundancy ? ; the cost of scrubbing the launch must have been
> enormous.
>
>
>
>

[Icebound]

"Dave S" > wrote in message
ink.net...
>
>
> Denny wrote:
>
>>
>> But, I would much rather be an astronaut who depends upon NASA
>> engineers to launch his tender body, than have been a cosmonaut under
>> the USSR's space program... Look up the available footage of some of
>> their more spectacular failures...
>>
>> denny
>>
> I want to say they have a body count of over 100 with regards to their
> early space program.
>

Where did you get that number?

[Dave S]

Icebound wrote:


> Where did you get that number?
>

One of the discovery channel programs on the soviet space program, which
I have not independently verified.

Dave

[Marco Leon]

So THAT'S why they say to always visually check the fuel level! How quickly
people forget from their primary training...

I think the Shuttle's fuel sensors were made by the same subcontractor that
made the fuel gauges in my Warrior.

Marco

"Granite" > wrote in message
.. .
> Discovery can't take off because of a bad fuel sensor ? Are they kidding
us
> ? The crew is already strapped in, number one for departure, cocked and
> loaded. We just put gas in the thing. I saw the line guys top the tanks
> earlier in the day. Stick the tank, placard the gas gauge inop and let's
go
> haul the mail ! Now it takes three or four days to replace it ? They
need
> to find a new A&P, preferably non-union. We are never going to get
> commercial space travel at this rate. I'm sure the FAA is to blame too
....
> somehow.
>
>



Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
----------------------------------------------------------
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[Icebound]

"Dave S" > wrote in message
ink.net...
>
>
> Icebound wrote:
>
>
>> Where did you get that number?
>>
>
> One of the discovery channel programs on the soviet space program, which I
> have not independently verified.
>


http://www.jamesoberg.com/

James Oberg gives a pretty detailed account of Soviet failures and myths. I
have not been able to find an actual "number" in his on-line stuff (buy the
books, I guess), but the implication is that some rumors of USSR space
deaths are overblown... and he also states that some is simply not known.

Now since he often appears on Discovery, so that "100" figure may be his (or
NOT), but his chapter at:
http://www.jamesoberg.com/usd10.html
does not seem to imply a number anywhere near that.

[Hilton]

Dave wrote:
> Denny wrote:
>
> >
> > But, I would much rather be an astronaut who depends upon NASA
> > engineers to launch his tender body, than have been a cosmonaut under
> > the USSR's space program... Look up the available footage of some of
> > their more spectacular failures...
> >
> > denny
> >
> I want to say they have a body count of over 100 with regards to their
> early space program.

I believe that number includes ground fatalities.

Hilton

[RST Engineering]

Hey, if my butt's on top of that firecracker, I want EVERYTHING in the green
before they light the fuse.

Jim


> Why so much redundancy ? ; the cost of scrubbing the launch must have been
> enormous.
>
>
>
>

[John Gaquin]

"Granite" > wrote in message news:m7nBe.146267

> .......We just put gas in the thing. I saw the line guys top the tanks
> earlier in the day. Stick the tank, placard the gas gauge inop and let's
> go
> haul the mail !


What a man!!!!

[Andrew Gideon]

Granite wrote:

> let'sÂ*go
> haul the mail

Is the UPS taking over for NASA? Considering the role played by the post in
aviation, that may not be a bad deal.

- Andrew

[John]

The simple answer is that the sensors are used to shut the engines down
before fuel exhaustion. The Space Shuttle Main Engine uses turbopumps
(that also burn liquid hydrogen and liquid oxygen) to pump sufficient
quantities of propellents to make it all go. The issue is that
turbopumps behave very badly, even destroying themselves if they are
run try, especially if at full power. It is apparently the nature of
the beasts. The sensors cue systems that begin to throttle the engines
back to about 65% power at which point the SSME can be shut down safely
and without damage.

Consider visiting the Science Space Shuttle News Group. Several people
asked the same question and the issue gets explained pretty clearly.
Someone noted that their car's fuel pump had a similar feature so to
protect it from burning itself out from running dry. Just like us, the
astronauts do not have the option of pulling the silly thing over to
the side of the road if something important decides to break.

blue skies to you all

John

[Mike Rapoport]

How do you "overspool" a rocket engine?

Mike
MU-2


"tony roberts" > wrote in message
news:nospam-33EADD.23165714072005@shawnews...
> The tanks contain hydrogen and oxygen. A combination of the two power it.
> If it runs out of either, it can blow, or overspool the engine - either
> would be fatal. So it needs accurate fuel sensors - unless you want to
> fly it. Crew safety is paramount - and right now it's compromised.
>
> Tony
> C-GICE
>
> In article >,
> "Granite" > wrote:
>
>> Discovery can't take off because of a bad fuel sensor ? Are they kidding
>> us
>> ? The crew is already strapped in, number one for departure, cocked and
>> loaded. We just put gas in the thing. I saw the line guys top the tanks
>> earlier in the day. Stick the tank, placard the gas gauge inop and let's
>> go
>> haul the mail ! Now it takes three or four days to replace it ? They
>> need
>> to find a new A&P, preferably non-union. We are never going to get
>> commercial space travel at this rate. I'm sure the FAA is to blame too
>> ...
>> somehow.
>
>
>
>
> --
>
> Tony Roberts
> PP-ASEL
> VFR OTT
> Night
> Cessna 172H C-GICE

[Ben Hallert]

The SSME (like all modern, high performance rocket engines) is a big
turbopump. Big turbines, run from the same fuel source as is being
ignited for use as a rocket. If the turbine is cranking away at full
power and the source of fuel suddenly goes dry, then all that power
being put into maintaining revs suddenly gets put into turbine speed.
Depending on if you're lucky or not, the engine will detect this and
shut off the turbine before it goes dry or before it overspeeds
destructively.

I wonder if these low-fuel sensors are part of the system that shuts
down the SSMEs if there's a fuel starvation issue. I remember a
mission a few years back where MECO (main engine cut-off) was
unexpectedly a few seconds early because of higher then projected fuel
burn or something. Not enough to really impact the mission, but it
showed the safety systems that prevent dry-running SSMEs was working.

Ben Hallert
PP-ASEL and space nut

[Mike Rapoport]

My recollection was that the turbopump used the engery in the expanding fuel
to pump the fuel. If the fuel runs out doesn't the turbopump stop pumping?

Mike
MU-2


"Ben Hallert" > wrote in message
oups.com...
> The SSME (like all modern, high performance rocket engines) is a big
> turbopump. Big turbines, run from the same fuel source as is being
> ignited for use as a rocket. If the turbine is cranking away at full
> power and the source of fuel suddenly goes dry, then all that power
> being put into maintaining revs suddenly gets put into turbine speed.
> Depending on if you're lucky or not, the engine will detect this and
> shut off the turbine before it goes dry or before it overspeeds
> destructively.
>
> I wonder if these low-fuel sensors are part of the system that shuts
> down the SSMEs if there's a fuel starvation issue. I remember a
> mission a few years back where MECO (main engine cut-off) was
> unexpectedly a few seconds early because of higher then projected fuel
> burn or something. Not enough to really impact the mission, but it
> showed the safety systems that prevent dry-running SSMEs was working.
>
> Ben Hallert
> PP-ASEL and space nut
>

[W P Dixon]

ALL RIGHT!!!
John I was wondering when someone would give the right reason! You have
won the prize my friend! ;) These fuel sensors cease fuel usage at the
proper time. If these little buggers go bad, well it would be possible to
run out of fuel before getting into outer space...that would not be good. I
think you did a good job of explaining it.

Patrick
student SPL
aircraft structural mech
I stayed in a Holiday Inn last night,
ok ok and old friend is a electrical engineer on the space shuttle ;)


"John" > wrote in message
ups.com...
> The simple answer is that the sensors are used to shut the engines down
> before fuel exhaustion. The Space Shuttle Main Engine uses turbopumps
> (that also burn liquid hydrogen and liquid oxygen) to pump sufficient
> quantities of propellents to make it all go. The issue is that
> turbopumps behave very badly, even destroying themselves if they are
> run try, especially if at full power. It is apparently the nature of
> the beasts. The sensors cue systems that begin to throttle the engines
> back to about 65% power at which point the SSME can be shut down safely
> and without damage.
>
> Consider visiting the Science Space Shuttle News Group. Several people
> asked the same question and the issue gets explained pretty clearly.
> Someone noted that their car's fuel pump had a similar feature so to
> protect it from burning itself out from running dry. Just like us, the
> astronauts do not have the option of pulling the silly thing over to
> the side of the road if something important decides to break.
>
> blue skies to you all
>
> John
>

[Judah]

tony roberts > wrote in
news:nospam-33EADD.23165714072005@shawnews:

> The tanks contain hydrogen and oxygen. A combination of the two power
> it. If it runs out of either, it can blow, or overspool the engine -
> either would be fatal. So it needs accurate fuel sensors - unless you
> want to fly it. Crew safety is paramount - and right now it's
> compromised.
>
> Tony
> C-GICE
>
> In article >,
> "Granite" > wrote:
>
>> Discovery can't take off because of a bad fuel sensor ? Are they
>> kidding us ? The crew is already strapped in, number one for
>> departure, cocked and loaded. We just put gas in the thing. I saw
>> the line guys top the tanks earlier in the day. Stick the tank,
>> placard the gas gauge inop and let's go haul the mail ! Now it takes
>> three or four days to replace it ? They need to find a new A&P,
>> preferably non-union. We are never going to get commercial space
>> travel at this rate. I'm sure the FAA is to blame too ... somehow.
>

But the regs say it only has to be accurate when empty!

[Ben Hallert]

Backwards, the exhaust of the turbopump is fed into the engine bell,
where the expansion takes place. You may be thinking of a turbo in a
piston engine, which runs parasitically off the exhaust. The pump has
to start before the fuel to get the fuel into the pump, right?
Chicken/Egg thing, there won't be any combustion in the chamber without
fuel being pumped into it.

Ben Hallert
PP-ASEL

[[email protected]]

>My recollection was that the turbopump used the engery in the expanding fuel
>to pump the fuel. If the fuel runs out doesn't the turbopump stop pumping?
>
>Mike
>MU-2

There are a number of differnet ways that turbopumps
on rockets can be powered, what you are describing is an expander cycle,
the SSME is a staged combustion pump.

The pump is preburinign some small amount of fule to spin the turbine,
if I recall it's about 150,000 HP per pump per engine.
This is a lot of power.

[AES]

I enjoyed the initial post in the original thread, taking it in the
spirit of a moderately clever kind of aviation-related standup comedy
routine.

And certainly no one has any desire to see the current Shuttle program
be terminated at the cost of, or as the result above, one more set of
crew fatalities.

But the bottom line here is surely that the whole manned space flight
effort and focus at NASA not only should be terminated as fast as
possible, but should have been terminated several decades ago, for at
least two major reasons.

First of all, manned space flight at this point in time is just too
difficult, dangerous, and expensive to be worth pursuing. It's a matter
of the laws of physics versus the currently available or currently
foreseeable level of technology, not the competence or the culture of
NASA. Maybe some future breakthrough in technology will make manned
space flight a much more reasonable goal; maybe not.

But by far the more compelling reason is that there are really zero
useful things, much less compelling needs, that we can or might want to
accomplish in space that are not better done with unmanned rather than
manned missions.

Something like two-thirds of NASA's budget for the past several decades
has gone into manned space flight efforts. Yet, essentially ALL of the
useful scientific and technological accomplishments in space to date --
space probes, planetary missions, space observatories, communications
satellites, gps systems, earth and environmental observatories,
surveillance satellites -- have come totally from UNmanned satellites;
and essentially ZERO significant results have come from manned space
flights.

Think about it: If you go into any moderately well equipped research or
manufacturing facility of any kind in any field these days, you don't
find scientists and technicians standing there turning knobs, watching
meters, and writing results in lab notebooks. You find instead either
highly automated, computer-controlled instruments and sample
manipulation equipment, along with similar observation, measurement, or
manufacturing apparatus, sitting there taking data, manipulating
samples, or modifying things, in many cases 24/7, while feeding data and
results back to hard disks and computers outside the lab, with maybe
occasional reprogramming from a scientist or tech at a keyboard in their
office or elsewhere outside the lab.

If you want to measure or observe or do anything in space, you put the
measurement and observation hardware in space, and keep the scientists
and engineers in shirt-sleeve comfort and safety on the ground -- and
you do this not just as as a matter of cost and safety, although these
are compelling reasons, but also because the observational and recording
capabilities of hardware these days far exceed the observational
capabilities of humans in any case.

Finally, just for the record, none of the above is to say we should not
have done the Apollo Project as we did it when we did it. That was a
much different era; Apollo was a proud and admirable accomplishment; it
was worth doing.

But now that we've come to understand a lot better what we really can do
and want to do in space using unmanned missions, and how unbelievably
much more it costs and how little we can really accomplish with manned
missions, we've just got to get over this astronaut hero worship phase
and start using our space efforts and resources much more intelligently.

[Jose]

> Finally, just for the record, none of the above is to say we should not
> have done the Apollo Project as we did it when we did it. That was a
> much different era; Apollo was a proud and admirable accomplishment; it
> was worth doing.

Why?

Earlier on you said

> First of all, manned space flight at this point in time is just too
> difficult, dangerous, and expensive to be worth pursuing.

Well, it was even more difficult, dangerous, and expensive in the Apollo
days. Most of your post seems to be that we should wait until space
travel is easy, safe, and cheap before we pursue it. You complain that
manned space research isn't impersonal enough (comparing it with
manufacturing facilities on earth), but then you single out the Apollo
program as being "a proud and admirable accomplishment" that was "worth
doing".

What's the difference?

I would posit the opposite. Manned space travel isn't bold, daring, and
audacious enough to capture our imagination and inspire mankind to do
better than blow up people who hold the wrong opinions. The space
shuttle has been, as NASA wanted it to be, "just a truck". Using the
shuttle to replace rockets was an error given the lack of anything
better than chemical rocket engines to power it. Instead we should have
(and should now) use expendable rockets to put stuff into orbit, and a
space station based fleet of mini-shuttles to do stuff with them once
the heavy lifting is done. Another fleet of mini-shuttles would be used
to carry people up and down - they would be the size of a lear jet and
have enough payload capability for six people and little else.

But the focus of our space program should be going to Mars and onward.

Because it's there.

Jose
--
Nothing takes longer than a shortcut.
for Email, make the obvious change in the address.

[Allen]

"Jose" > wrote in message
m...
> better than chemical rocket engines to power it. Instead we should have
> (and should now) use expendable rockets to put stuff into orbit, and a
> space station based fleet of mini-shuttles to do stuff with them once the
> heavy lifting is done. Another fleet of mini-shuttles would be used to
> carry people up and down - they would be the size of a lear jet and have
> enough payload capability for six people and little else.
>
> But the focus of our space program should be going to Mars and onward.
>
> Because it's there.
>
> Jose

Funny you should say that. There is a company in Oklahoma that plans on
taking a stripped Lear 25 fuselage, bolting it to a basic wing, adding
turbofan engines and a re-useable rocket engine. Take-off and climb to
30,000 feet of the turbofans, light the rocket and climb to 158,000 feet,
then coast to about 330,000 feet before gliding back to earth. All in a half
hour flight. www.rocketplane.com

Allen

[Skywise]

"Icebound" > wrote in
:

>
> "Dave S" > wrote in message
> ink.net...
>>
>>
>> Icebound wrote:
>>
>>
>>> Where did you get that number?
>>>
>>
>> One of the discovery channel programs on the soviet space program,
>> which I have not independently verified.
>>
>
>
> http://www.jamesoberg.com/
>
> James Oberg gives a pretty detailed account of Soviet failures and
> myths. I have not been able to find an actual "number" in his on-line
> stuff (buy the books, I guess), but the implication is that some rumors
> of USSR space deaths are overblown... and he also states that some is
> simply not known.
>
> Now since he often appears on Discovery, so that "100" figure may be his
> (or NOT), but his chapter at:
> http://www.jamesoberg.com/usd10.html
> does not seem to imply a number anywhere near that.

Try this article of his....
http://www.astronautix.com/articles/therophe.htm

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism

Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Blog: http://www.skywise711.com/Blog

Sed quis custodiet ipsos Custodes?

[Bob Noel]

In article >,
Jose > wrote:

[snip]
> But the focus of our space program should be going to Mars and onward.
>
> Because it's there.

Absolutely!!!

--
Bob Noel
no one likes an educated mule

[Icebound]

"Skywise" > wrote in message
...
> "Icebound" > wrote in
> :
>
>>
>> "Dave S" > wrote in message
>> ink.net...
>>>
>>>
>>> Icebound wrote:
>>>
>>>
>>>> Where did you get that number?
>>>>
>>>
>>> One of the discovery channel programs on the soviet space program,
>>> which I have not independently verified.
>>>
>>
>>
>> http://www.jamesoberg.com/
>>
>> James Oberg gives a pretty detailed account of Soviet failures and
>> myths. I have not been able to find an actual "number" in his on-line
>> stuff (buy the books, I guess), but the implication is that some rumors
>> of USSR space deaths are overblown... and he also states that some is
>> simply not known.
>>
>> Now since he often appears on Discovery, so that "100" figure may be his
>> (or NOT), but his chapter at:
>> http://www.jamesoberg.com/usd10.html
>> does not seem to imply a number anywhere near that.
>
> Try this article of his....
> http://www.astronautix.com/articles/therophe.htm
>

Thanks.... in the index on his "Russian" page, I had skipped right over that
one to "Uncovering Soviet Disasters; Chapter on Dead Cosmonauts", several
items below. Thanks again.

[George Patterson]

Judah wrote:
>
> But the regs say it only has to be accurate when empty!

Wrong.

George Patterson
Why do men's hearts beat faster, knees get weak, throats become dry,
and they think irrationally when a woman wears leather clothing?
Because she smells like a new truck.

[Jose]

>> Another fleet of mini-shuttles would be used to
>> carry people up and down - they would be the size of a lear jet and have
>> enough payload capability for six people and little else.
>
> Funny you should say that. There is a company in Oklahoma that plans on
> taking a stripped Lear 25 fuselage, bolting it to a basic wing, adding
> turbofan engines and a re-useable rocket engine. Take-off and climb to
> 30,000 feet of the turbofans, light the rocket and climb to 158,000 feet,
> then coast to about 330,000 feet before gliding back to earth. All in a half
> hour flight.

Perhaps I should have been clearer... "Another fleet of mini-shuttles
would be used to carry people up and down, and get them going five miles
per second to meet with other stuff up there." :)

Jose
--
Nothing takes longer than a shortcut.
for Email, make the obvious change in the address.

[Morgans]

"Ben Hallert" > wrote

> I wonder if these low-fuel sensors are part of the system that shuts
> down the SSMEs if there's a fuel starvation issue. I remember a
> mission a few years back where MECO (main engine cut-off) was
> unexpectedly a few seconds early because of higher then projected fuel
> burn or something. Not enough to really impact the mission, but it
> showed the safety systems that prevent dry-running SSMEs was working.

That was exactly the problem. The main engines shut off at zero fuel level,
and with the sensor reading zero fuel, the engine would not even start. Not
a "good' thing.
--
Jim in NC

[Hilton]

Morgans wrote:
>
> "Ben Hallert" > wrote
>
> > I wonder if these low-fuel sensors are part of the system that shuts
> > down the SSMEs if there's a fuel starvation issue. I remember a
> > mission a few years back where MECO (main engine cut-off) was
> > unexpectedly a few seconds early because of higher then projected fuel
> > burn or something. Not enough to really impact the mission, but it
> > showed the safety systems that prevent dry-running SSMEs was working.
>
> That was exactly the problem. The main engines shut off at zero fuel
level,
> and with the sensor reading zero fuel, the engine would not even start.
Not
> a "good' thing.

There are four sensors - NASA could have removed this (apparently) faulty
sensor from the voting.

Hilton

[Ben Hallert]

I'm guessing that they're deciding that they don't want to launch with
the loss of avoidable redundancy. If they lose a sensor after they're
off the pad, that's one thing. But would you embark on a cross country
after losing your vacuum system? Why not, you have the electric
instruments that your IFR training showed you how to use as a
backup....?

Same thing with them, plus a healthy dose of CYA, nobody wants to be
'that guy that said launch anyways' right before it asplodes, and turns
out that it's because of a short in the faulty sensor that, I dunno,
caused a leak of LOX into the H2 tank or something.

Ben Hallert
PP-ASEL

[Ben Hallert]

Quick followup, the SSME does not have a restart-in-flight mode, so
once it's shut down, it stays off until after the shuttle is back on
the ground.

Ben Hallert
PP-ASEL

[[email protected]]

AES wrote:

> But the bottom line here is surely that the whole manned space flight
> effort and focus at NASA not only should be terminated as fast as
> possible, but should have been terminated several decades ago, for at
> least two major reasons.

Well, at this point I think manned spaceflight needs to be saved *from*
NASA, not *by* it.

> First of all, manned space flight at this point in time is just too
> difficult, dangerous, and expensive to be worth pursuing. It's a matter
> of the laws of physics versus the currently available or currently
> foreseeable level of technology, not the competence or the culture of
> NASA. Maybe some future breakthrough in technology will make manned
> space flight a much more reasonable goal; maybe not.

"Future breakthrough[s] in technology" do not fall out of trees. Once
upon a time, flying at FL450 was "difficult, dangerous, and expensive."
But because we kept doing it, failing with often lethal results, it is
now as safe (or safer) as traveling on the ground.

> But by far the more compelling reason is that there are really zero
> useful things, much less compelling needs, that we can or might want to
> accomplish in space that are not better done with unmanned rather than
> manned missions.

Perhaps. This is where the argument turns from a matter of reason into
one more like faith. There is little that astronauts could do on the
surface of Mars that we cannot at this time do faster and more cheaply
with robots. BUT...

The challenge of sending a human crew to the surface of Mars, and
bringing it back to Earth intact, would I think serve to spur the
development of many things with more quotidian uses. With a mission
likely to last several years, one problem is healthcare. Many things
can happen, and even if you put a doctor on the crew you have to allow
(a) that he won't know everything and (b) he may get injured himself.
So, you need to provide alternatives: computerized monitors which can
observe the body and render diagnoses, and possibly devices which allow
people with less than an MD to provide meaningful care. Healthcare is
currently 15% of our economy, and growing without bounds. Surely such
research could have revolutionary impact on our lives.

The bureaucracy and legal/financial obstacles to developing such things
in the pure civilian world mean that advancements will come slowly at
best. In wartime, governments, businesses, and people are willing to
take all manner of chances because victory depends upon it. Even Stalin
gave up shooting his political opponents for a few years during WWII
when it was clear that the Nazis might roll them all over.

Similarly, the Apollo program provided an imperative of sufficient
power to justify innovation at all costs. Frontiers are, always have
been, and always will be dangerous places, but behind the pioneers come
settlers.

And then of course there is the point that man does not live by bread
alone. You concede that the Apollo program was the right thing to do at
the time, though it had little direct scientific merit. What about
today? Imagine the whole world, from Shanghai, to Tehran, to Paris, and
Los Angeles watching as an American backed down a ladder onto the
surface of Mars. Now imagine that the astronaut is a Muslim woman, who
came here as an immigrant to be educated in our great universities.
Laugh, shake your head, scream "PC!" or whatever, but don't tell me
this wouldn't cast an amazing shadow across the landscape.

-cwk.

[Mike Weller]

On Thu, 14 Jul 2005 13:14:22 -0700, wrote:

>
>>My recollection was that the turbopump used the engery in the expanding fuel
>>to pump the fuel. If the fuel runs out doesn't the turbopump stop pumping?
>>
>>Mike
>>MU-2
>
>There are a number of differnet ways that turbopumps
>on rockets can be powered, what you are describing is an expander cycle,
>the SSME is a staged combustion pump.
>
>The pump is preburinign some small amount of fule to spin the turbine,
>if I recall it's about 150,000 HP per pump per engine.
>This is a lot of power.
>

The F-1 turbines for the engines on the Saturn V first stage each
produced, nominally, about 54,000 horses. Times five that is a huge
amout of power that needs to be harnesed. 7.6 Million pounds of
thrust was the result of that. Your Garretts should stand back in
awe.

Mike Weller

[Mike Weller]

On Thu, 14 Jul 2005 19:22:33 GMT, Judah > wrote:

>But the regs say it only has to be accurate when empty!

You haven't flown a Mooney have you?

Time and fuel amount are your friends.

Mike Weller

[Mike Rapoport]

"Mike Weller" > wrote in message
news:1121443598.642f01f4298df066c5b035efb54d5426@o nlynews...
> On Thu, 14 Jul 2005 13:14:22 -0700, wrote:
>
>>
>>>My recollection was that the turbopump used the engery in the expanding
>>>fuel
>>>to pump the fuel. If the fuel runs out doesn't the turbopump stop
>>>pumping?
>>>
>>>Mike
>>>MU-2
>>
>>There are a number of differnet ways that turbopumps
>>on rockets can be powered, what you are describing is an expander cycle,
>>the SSME is a staged combustion pump.
>>
>>The pump is preburinign some small amount of fule to spin the turbine,
>>if I recall it's about 150,000 HP per pump per engine.
>>This is a lot of power.
>>
>
> The F-1 turbines for the engines on the Saturn V first stage each
> produced, nominally, about 54,000 horses. Times five that is a huge
> amout of power that needs to be harnesed. 7.6 Million pounds of
> thrust was the result of that. Your Garretts should stand back in
> awe.
>
> Mike Weller
>
>
I can't afford to pay for 15 tons of fuel and O2 per second anyway.

Mike
MU-2

[Allen]

"Mike Rapoport" > wrote in message
ink.net...
>
>>>
>>
> I can't afford to pay for 15 tons of fuel and O2 per second anyway.
>
> Mike
> MU-2
>

Uh Mike, you are paying for it. So am I :)

Allen

[Judah]

George Patterson > wrote in
news:15FBe.6001$Om4.2374@trndny07:

> Judah wrote:
>>
>> But the regs say it only has to be accurate when empty!
>
> Wrong.
>
> George Patterson
> Why do men's hearts beat faster, knees get weak, throats become
> dry, and they think irrationally when a woman wears leather
> clothing? Because she smells like a new truck.
>

I know. It was a joke. We've had that conversation already.

[Mike Rapoport]

Yeah but all 100MM of us taxpayers are paying. If I owned a Saturn V, I
could only split the fuel three ways.

Mike
MU-2


"Allen" > wrote in message
. ..
>
> "Mike Rapoport" > wrote in message
> ink.net...
>>
>>>>
>>>
>> I can't afford to pay for 15 tons of fuel and O2 per second anyway.
>>
>> Mike
>> MU-2
>>
>
> Uh Mike, you are paying for it. So am I :)
>
> Allen
>