The first human mars mission?

"Henry Spencer" wrote in message
...
In article ,
Christopher wrote:
Could the shuttle go up just as well using paraffin/kero and lox the
same as with it's current hydrogen fuel?

The SRBs might have to get somewhat larger, because the gross liftoff mass
of the orbiter plus ET would be higher. On the other hand, the ET itself
would get smaller and lighter (heavier when filled, but lighter when
empty) -- it's currently mostly LH2 tank.

Or the same size ET would hold sufficient dense fuels to supply
liquid booster engines also, eliminating the SRBs.

MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

On Wed, 8 Oct 2003 03:37:48 GMT, (Henry Spencer)
wrote:

In article ,
Christopher wrote:
...Hydrogen is a lousy fuel; people are mesmerized by its high
Isp, and forget the heavy tanks and plumbing and the poor engine T/W.
What we care about is delta-V, not Isp, and the former is often actually
easier to get with fuels like kerosene.

Could the shuttle go up just as well using paraffin/kero and lox the
same as with it's current hydrogen fuel?

The SRBs might have to get somewhat larger, because the gross liftoff mass
of the orbiter plus ET would be higher. On the other hand, the ET itself
would get smaller and lighter (heavier when filled, but lighter when
empty) -- it's currently mostly LH2 tank.

Intersting. However would the launch cost's be the same or lower for
a kero-lox fueled shuttle?

Even setting that aside, note that the SSME is an incremental refinement
of Pratt&Whitney's 1960s RL20/XLR129 high-pressure-engine work. Nothing
very new there.

Didn't know that.

P&W was intensely ****ed off about it too -- from their viewpoint, NASA
led them on and had them do all the pioneering development of a somewhat
difficult technology, and then when it came time for a big production
contract, handed it to their arch-competitor and told them to get lost.

That's nasty, I don't like that, not very nice of NASA, P&W didn't
deserve it, as they to have to make a living. However, I [and maybe
lots of other people] was under the impression that the SSME was
cutting edge in rockets, ah well, I suppose that title is still held
by that Russian engine they developed for their moon rocket.

The improvements to be had are (with possible minor exceptions) not in new
fuels, but in better engines -- higher expansion ratios with altitude
compensation, lighter weight, longer operating life, lower costs.

So, what your saying is rocket engines could be developed like the
internal combustion engine has been, in that the car engine of 1963 is
a totally primative engine compaired to the 2003 car engine as we have
seen 40 years of development take place?

Right general idea, except that I would compare today's rocket engines to
the car engines of 1903, or maybe 1893, not 1963.

It seems we haven't advanced that far since Dr Goddard's first liquid
fueled launch in 1926, just increased the size of the engines or 77
years of more or less stationary progress.




Christopher
+++++++++++++++++++++++++
"Kites rise highest against
the wind - not with it."
Winston Churchill

"Christopher" wrote in message
...

Intersting. However would the launch cost's be the same or lower for
a kero-lox fueled shuttle?

Considering the fuel costs are "in the noise" that wouldn't change. Most of
the shuttle costs are support costs, things like paying for the janitors in
the VAB, painting the MLPs, etc.



That's nasty, I don't like that, not very nice of NASA, P&W didn't
deserve it, as they to have to make a living. However, I [and maybe
lots of other people] was under the impression that the SSME was
cutting edge in rockets, ah well, I suppose that title is still held
by that Russian engine they developed for their moon rocket.

Bleeding edge might be more appropriate. At this point rather than fighting
for every last bit of ISP, we'd be better off designing engines that are as
re-usable as your car engine. I.e. extremely. (and in fact you'll find some
of the more recent SSME upgrades go a long way to safety and reliability at
the cost of a little performance.)


The improvements to be had are (with possible minor exceptions) not in
new
fuels, but in better engines -- higher expansion ratios with altitude
compensation, lighter weight, longer operating life, lower costs.

So, what your saying is rocket engines could be developed like the
internal combustion engine has been, in that the car engine of 1963 is
a totally primative engine compaired to the 2003 car engine as we have
seen 40 years of development take place?

Right general idea, except that I would compare today's rocket engines to
the car engines of 1903, or maybe 1893, not 1963.

It seems we haven't advanced that far since Dr Goddard's first liquid
fueled launch in 1926, just increased the size of the engines or 77
years of more or less stationary progress.

Well, effeciency-wise we've come some ways. In terms of serviceability,
cost to manufacture, etc, we've got a long ways to go.






Christopher
+++++++++++++++++++++++++
"Kites rise highest against
the wind - not with it."
Winston Churchill

In article ,
Christopher wrote:
Could the shuttle go up just as well using paraffin/kero and lox the
same as with it's current hydrogen fuel?
The SRBs might have to get somewhat larger...the ET itself
would get smaller and lighter...

Intersting. However would the launch cost's be the same or lower for
a kero-lox fueled shuttle?

As Greg has already noted, fuel costs are pretty insignificant compared to
all the manpower involved. That said, fuel costs would in fact be lower,
despite the greater mass of fuel: liquid hydrogen is fairly expensive,
kerosene is cheap, LOX is very cheap.

...I [and maybe
lots of other people] was under the impression that the SSME was
cutting edge in rockets, ah well...

Most everybody in the West thought so at the time. Only when Russia
opened up did it become clear that the Russians had been building similar
engines -- in some ways better -- since the early 1960s, and every new
Russian rocket was using them. (The Russians didn't use liquid hydrogen,
but they did run their preburners oxidizer-rich, which in the West was
thought so difficult that when word about it first got out, some US rocket
engineers wondered if it was disinformation.)
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

On Wed, 8 Oct 2003 13:26:31 GMT, (Henry Spencer)
wrote:

In article ,
Christopher wrote:
Could the shuttle go up just as well using paraffin/kero and lox the
same as with it's current hydrogen fuel?
The SRBs might have to get somewhat larger...the ET itself
would get smaller and lighter...

Intersting. However would the launch cost's be the same or lower for
a kero-lox fueled shuttle?

As Greg has already noted, fuel costs are pretty insignificant compared to
all the manpower involved. That said, fuel costs would in fact be lower,
despite the greater mass of fuel: liquid hydrogen is fairly expensive,
kerosene is cheap, LOX is very cheap.

That coupled with more relible engines, and smaller more reliable mini
shuttles and things might start improving for regular access to space.

...I [and maybe
lots of other people] was under the impression that the SSME was
cutting edge in rockets, ah well...

Most everybody in the West thought so at the time. Only when Russia
opened up did it become clear that the Russians had been building similar
engines -- in some ways better -- since the early 1960s, and every new
Russian rocket was using them. (The Russians didn't use liquid hydrogen,
but they did run their preburners oxidizer-rich, which in the West was
thought so difficult that when word about it first got out, some US rocket
engineers wondered if it was disinformation.)

BBC2 did a Horizon program on it some months ago, it was a massive
shock to the American rocket industries system, and the Russians also
continue to use kero and lox as fuel.



Christopher
+++++++++++++++++++++++++
"Kites rise highest against
the wind - not with it."
Winston Churchill

McLean1382 wrote:

Henry Spencer writes:

So? Fuel is cheap, especially if you don't insist on using liquid
hydrogen.

Right, but twice as much fuel requires twice as much engine to push it, and
engines *aren't* cheap.

Jet engines aren't cheap either, but they're designed for long life,
reliability, and maintainability, so the cost per flight is low. Rocket
engines like the SSME were designed for maximum performance with minimum
mass, so they are high maintenance and high cost items. Even so, the
cost of maintaining the SSME's is a small portion of the cost of a
Shuttle launch.

Lifting all the liquid oxygen required by a rocket-powered launch
vehicle requires a lot of thrust, and maintaining the rocket engines
that generate that thrust will eventually be one of the major drivers in
the cost of Earth-to-orbit transportation, but we have a long way to go
before we get to that point. Liquid oxygen is dirt cheap - buying and
maintaining the hardware is what costs money, and it is worth noting
that the ratio of dry mass to payload for a 2-stage, liquid fueled, VTOL
RLV would not be that much different than the ratio for commercial
aircraft.

Will McLean

(McLean1382) writes:

Henry Spencer writes:

So? Fuel is cheap, especially if you don't insist on using liquid
hydrogen.

Right, but twice as much fuel requires twice as much engine to push it, and
engines *aren't* cheap.


In particular, hydrogen-burning engines are roughly twice as expensive,
per unit thrust, as kerosene-burners. Rocket engines are basically
ultra-high-performance pumps with a bit extra tacked on the end, and
you pump volume, not mass.

This is not to say that hydrogen is the *wrong* propellant; it's quite
competitive, and you have to do the math for your particular mission
model. The problem is the belief that hydrogen is so obviously the
*right* propellant that people skip the math.


--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *

Robert =?ISO-8859-1?Q?Kitzm=FCller?= writes:

John Schilling wrote:

Robert =?ISO-8859-1?Q?Kitzm=FCller?=
writes:

However, NASA *would* be able to do a manned Mars-mission given the
necessary funding (=lots and lots of cash),

No. This is a very common misconception, and NASA thanks you for it.

But, in fact, "necessary funding" !!!!!= "lots and lots of cash".

If you hand NASA a check for a *trillion* dollars, and tell them to
get their ass to Mars, you will wind up with junkyards filled with
half-built hardware, mansions filled with rich retired LockMart and
BoeDonnel bigwigs, and petabytes of Powerpoint slides explaining
why it will take at least two trillion dollars to put a man on Mars.

This seems likely, but there is another point...

I am not making this up, and I am not exaggerating. Remember, last
time anyone at all serious about it asked NASA for an estimate for a
Mars program, they seriously said, "four hundred billion". Add in
your own best guess as to the overruns, and do the math.

This seems likely, but there is another point...

NASA is overwhelmingly dominated by people who are absolutely incapable
of building spaceships. They do not have those skills. This is not to
say that they are unskilled. They are *very skilled at: making
Powerpoint viewgraphs, asking for money, excusing their past failures
at spaceship building, getting in bed with contractors with the same
skillset, forging new employees to the same temper, suppressing
employees who insist on embarassing them by building conspicuously
successful spaceships, and protecting their budgets, their empires, and
most especially their jobs with ruthless efficiency.

There is *no* sum of money that can be added to NASA's budget that will
result in Mars-bound spaceships. Only viewgraphs, excuses, and claims
that with twice as much money they'll get the job done. And that last
bit is recursive.

I do not agree with this paragraph. I do think that people (a lot of
them, not all) with space ambitions, space enthusiasm and engeneering
skill do turn to NASA, even if they do not utilize their skill right
now.

Yes, they do. This changes nothing.

A lot of ambitious, enthusiastic, and very talented young scientists
and engineers with their eyes on the stars take jobs at NASA.

All the ambitious, enthusiastic, talented young scientists and engineers
in the world, even with the aforementioned trillion dollars, will not
suffice to put together a Mars expedition.

For that you nead *teams*, which are more than just a collection of
individuals, and in this case you nead teams that include not just
talented young scientists and engineers but experienced veterans
and, shock and horror, *managers*.

NASA, with a few small exceptions clustered around JPL, does not have
efficient project teams, does not have veteran engineers with experience
in actual spacecraft design and construction, and does not have managers
capable of putting such teams together. The ambitious, enthusiastic,
talented young scientists and engineers who join NASA with dreams of
spaceflight, never learn the skills they need to accomplish such, and
whatever innate talent they have along those lines is at best allowed
to atrophy and at worst hammered *out* of them.


The other point from above is: Give them a firm deadline. Deadline
as in dead: Tell them: "Show progress, or the whole managment gets fired.
On the second offense, NASA gets disbanded. Get us to mars, or else!"
And tell them you mean it, and be prepared to carry it through, and
set USAF, or Joes hardware store, or someone else to the task if NASA
does not perform.

You have just rediscovered the project management philosophy of the
former Soviet Union, and we all know how well it worked there.

It has, of course, three absolutely crucial flaws.

First, nobody will believe you. Disbanding a government agency of
NASA's scale is very nearly unprecedented, it's not clear that there
is anyone who has the power to actually do it, and even if you were
such a person and were sincere in your resolve, nobody at NASA is
a telepath and/or in posession of a working crystal ball. Based on
all available outside evidence, any rational observer would conclude
that you were bluffing, that you were a loose cannon doomed to lose
his own job in short order, or both.

Second, motivation is not a substitute for skill. Again, the skills
necessary to build spaceships do not exist at NASA, and even if you
threaten them all with death by slow torture, the skills will still
not exist and so the project will still fail. That NASA doesn't
particularly care to build working spaceships is only a secondary
problem. The main problem is that NASA is absolutely incapable of
building working spaceships even if it wanted to.

Third, even if you did convince NASA management that you were serious
and that they needed to embark on a crash course of skill development,
the rational course of action would be for them to develop the skills
that they are already actually good at, such as applied politics and
bureaucracy. If they attempt to learn how to build spaceships, they
are starting from scratch with mostly unqualified people, and they
will almost certainly fail.

If instead they focus on unseating you from whatever position of power
allows you to make such threats, or of building an effective defense
against your power, their odds are much better.


A lot of people in NASA see their job as protecting their job, which
means right now extend program lengths as much as possible. Change the
rules of the game, and you would get result.

Change the rules of the game, and you get a bunch of people who don't
know how to play the new game. Again, useful skills do not appear
simply because you mandate them.


But even so, it would still cost lots and lots of money.

Anybody who can do the job at all, can do it on one-tenth NASA's present
budget. And if, hypothetically, you found yourself with the power to
fire NASA management, your only hope would be to fire *up front* anyone
who disagrees with that statement, which would conveniently ammount to
at least nine-tenths of NASA's present management. Mere threats will
just cause them to entrench themselves even deeper in their present
position.

But then you'd have to rebuild a decimated organization, which is at
least as difficult and tedious as starting from scratch, so you might
as well leave NASA in place and start from scratch. Just plan your
operations so you stay beneath your radar until you have effective
defenses against NASA-scale bureaucratic attacks.


--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *

Henry Spencer wrote:
A related issue, if you're making cryogenic fuels from CO2,
is making sure that the fuels don't have any significant CO2
contamination. CO2 is a solid at cryo temperatures, it can clog
plumbing, and filtering it out of liquids like LOX is notoriously
difficult.

Wouldn't reasonable amounts of it dissolve in liquid oxygen, and stay
dissolved, rather than ever condensing out?
--
Keith F. Lynch - - http://keithlynch.net/
I always welcome replies to my e-mail, postings, and web pages, but
unsolicited bulk e-mail (spam) is not acceptable. Please do not send me
HTML, "rich text," or attachments, as all such email is discarded unread.

In article ,
Keith F. Lynch wrote:
...making sure that the fuels don't have any significant CO2
contamination. CO2 is a solid at cryo temperatures, it can clog
plumbing, and filtering it out of liquids like LOX is notoriously
difficult.

Wouldn't reasonable amounts of it dissolve in liquid oxygen, and stay
dissolved, rather than ever condensing out?

Unfortunately, no. It is only slightly soluble in LOX, 4-5ppm at LOX's
boiling point. If it is near saturation -- as it often is in garden-
variety LOX on Earth -- then small changes in tank conditions, or even LOX
boiling off in steady state (thus concentrating contaminants), can
precipitate it out. There is often CO2 snow at the bottom of LOX storage
tanks on Earth.

Worse yet, it does not redissolve easily, and no known filter reliably
catches it all.

(Ref: Applied Cryogenic Engineering, Vance ed.)
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |