Cost of launch and laws of physics

(Greg Kuperberg) wrote:

In article ,
Joann Evans wrote:

are those that hide behind the heat tiles and the RCC panels. But if
the helicopter blades are supposed to hide behind the rest of the
"Roton", how would they slow it down?
Much the same way parachutes on a ballistic capsule do.

So you're telling me that the flight tests and all of that were just to
avoid parachutes? If you hope to fly into space, it is not enough to
invent a new kind of parachute.

If one hopes to fly into space cheaply and routinely, one does need
developments of this sort.

But you'd know that if you were anything other than a troll.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.

John Ordover wrote:
The physics problem is that we do not know how, within the laws of
physics, to build a cheap, simple, "model-T" space vehicle that is
affordable to the common man, or even the common corporation.

Perhaps we will one day figure it out. Nothing on in the near-term,
IMHO, promises to do that.

We do - you just have to leaveoff the 'and takes off/lands from/on
a planet with an atmosphere'.

--
Sander

+++ Out of cheese error +++

On Fri, 08 Aug 2003 18:15:59 GMT, in a place far, far away,
(Derek Lyons) made the phosphor on my monitor
glow in such a way as to indicate that:

Earl Colby Pottinger wrote:
Also note, without all the extras the first cars were built in barns and
garages by people who often had not even finish high school. And the same
can be said about many of the first airplanes.

Also note that a lot of those were outright failures and a significant
number killed their operators.

Which is a very effective way of quickly weeding out what works and
what doesn't.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

On Wed, 6 Aug 2003 09:12:53 +0000 (UTC), "Dave"
wrote:

I recently flew Concorde which was full, but mostly of aviation enthusiasts
like me who had had a chance at a low cost ticket, all of us were pretty
much at the limit of what our partners would allow us to spend on a one-off
treat. Still, the low cost approach seems to have worked with Concorde, it
is fully booked pretty much until they stop flying it.

I too flew in Concorde, but I didn't need my partner's approval. He
was right there beside me. We didn't get a low-cost ticket but we did
fly when the franc was very low against the dollar.

I got some incredible pictures out of the window at 58,000 feet which,
sadly, probably about as high as I expect to ever get to fly.

Yeah, me too, but I'm not that big a fan of zoom climbs. Besides,
pressure suits are pretty uncomfortable.

It's also about as fast as I ever expect to fly, too. If all I'd
wanted to do was fly faster, I could have done so on my F-104 flight,
but that's all we'd have done. I managed to convince myself that over
Mach 1 was good enough, not knowing the Concorde flight was in the
future.

Mary

--
Mary Shafer Retired aerospace research engineer

h (Rand Simberg) wrote:

On Fri, 08 Aug 2003 18:15:59 GMT, in a place far, far away,
(Derek Lyons) made the phosphor on my monitor
glow in such a way as to indicate that:

Earl Colby Pottinger wrote:
Also note, without all the extras the first cars were built in barns and
garages by people who often had not even finish high school. And the same
can be said about many of the first airplanes.

Also note that a lot of those were outright failures and a significant
number killed their operators.

Which is a very effective way of quickly weeding out what works and
what doesn't.

Very true, but it does weigh the debit side of the publicity and
public perception ledger down a bit.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.

Greg Kuperberg wrote:
are those that hide behind the heat tiles and the RCC panels. But if
the helicopter blades are supposed to hide behind the rest of the
"Roton", how would they slow it down?
Much the same way parachutes on a ballistic capsule do.

So you're telling me that the flight tests and all of that were just to
avoid parachutes? If you hope to fly into space, it is not enough to
invent a new kind of parachute.


Ok, Greg... look. We know you're opinionated, and that's fine
when you're making politics arguments like the 'is manned spaceflight
any good' stuff.

But this is engineering and physics. Not understanding and
throwing sarcasm into play is not a wise choice.

Please listen and pay attention. Once you understand what is
going on, then if you feel like forming an educated opinion you
want to share with us, that's fine. If you are unclear on a point
please say so without the 'tude, and you should in return expect
(and hopefully, get) straightforwards answers.

Roton was intended to be a single stage to orbit fully reusable
launch vehicle. The landing problem, in general, is a large problem
for any reusable launch vehicle. Reusability implies that landings
have to be fairly soft, and manned vehicles require even softer.
Operational concerns mean that landing on specific points, say the
end of the runway as opposed to "somewhere within five miles of this
point here, out in the dry lakebed", are a big concern. Using aerodynamics
is preferable to using landing rockets, because the weights seem to be
about the same but landing rockets are a little less reliable than
lifting surfaces. Landing on land, for reusable vehicles, is very
important.

Winged gliders are one answer to this, but suffer from large weight
penalties and poor landing abort / hold during descent characteristics.
Parachutes by themselves don't offer enough performance to land slowly
enough for human tolerances, though you could conceivably have unmanned
RLVs landing that hard repeatedly. Parafoils can flare, so they can have
lower terminal vertical velocity, but suffer some of the downsides of
winged gliders. Parachutes plus landing rockets are used on Soyuz.
Winged gliders with some power (rockets or jet engines) have been
considered as well, but never flown. They are heavy.

The Roton landing concept was a potentially very elegant solution;
moderate crossrange, good controlability, the ability to hover for a
little while at least, the ability to flare to low touchdown velocity,
something that is mostly working via aerodynamics and therefore is less
likely to break, etc.

Note that these are all the advantages on paper; implimentation and
verification of characteristics were under way, but not completed.

So yes, the rotor was intended to do what parachutes can do, but are
not well suited for doing on a RLV intended to land on land.
And yes, this is a very important part of the operational cycle
for a SSTO RLV. Had it worked as advertised it would have been a
major step forwards. But it had nothing to do with re-entry or the
ascent systems, other than avoiding damaging the rotor in those flight
phases.


-george william herbert

Greg Kuperberg wrote:
What he said in context was, first, that re-entry would be a "pretty
benign" environment, and second, that it would be "no worse" than what the
shuttle experiences. But as the destruction of STS-107 makes clear, the
shuttle's environment during re-entry is not remotely benign. People in
this thread said something rather different from the Hudson quote:
that the Roton blades would encounter an environment which is much more
benign than shuttle re-entry, not "no worse".

Now STS-107 broke apart at 210,000 feet moving at Mach 18. How fast is
the Roton supposed to go at that altitude, and what are the helicopter
blades supposed to do then? If they are retracted entirely, at what
altitude and velocity are they supposed to deploy? Taking the laws
of physics seriously requires clear answers to questions like this.
Even answers to within a factor of 2 would be a start.

Re-entry vehicles other than ballistic missile RVs have a hot side
and a cooler side. Well, even RVs have a cooler spot on the back,
but it's not very big.

The 'front side' of the shuttle has very high temperature exposed
edges (leading edges, RCC panels) and moderately high temperature
large surface areas (black tiles). The 'back side' of the shuttle
has moderately low to fairly low temperature areas. Some of the
areas are protected by essentially flexible quartz fabric blankets,
and experience no more peak temperature or temperature duration
than is seen cooking a posteak on the barbequeue. The insulation is
required primarily because Aluminum's high temperature tolerance
is terrible; if the upper surfaces were made of steel or titanium
you could get away without insulating them, just making sure that
heat leaking in didn't fry wiring or hydraulics inside, etc.

In the Roton vehicle design, the base reenters first, and has the
high heat loading areas. The hypersonic aerodynamics mean that
the hot high temperature gas flows off with the primary shockwave,
and stays well away from the sides of the vehicle. Though the
environment at the sides of the vehicle, and at the top and out
where the rotors would be, is pretty hot, it's like what you see
on the back side of the shuttle. Not 'melt everything not covered
in RCC, tiles, or ablator' hot; cool enough that inconel and
other high temperature alloys will be fine, at least.


-george william herbert

On Fri, 08 Aug 2003 21:55:50 GMT, in a place far, far away,
(Derek Lyons) made the phosphor on my monitor
glow in such a way as to indicate that:

Also note that a lot of those were outright failures and a significant
number killed their operators.

Which is a very effective way of quickly weeding out what works and
what doesn't.

Very true, but it does weigh the debit side of the publicity and
public perception ledger down a bit.

I suspect that the attrition rate will be much lower for rockets than
it was for aircraft, at least in the US, because even if not
certifying, the FAA will be involved, and the things necessary to get
launch license will imply a higher level of analysis up front. Also,
although we don't yet know how to do it routinely and cheaply, we have
a much better understanding of the physics now than most people did
about control theory and aerodynamics at the beginning of the
twentieth century.

I suspect that most of the evolutionary pressure will be due to
economics, rather than disasters and death.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

(John Ordover) wrote in message . com...
John apparently believes that everyone is as ignorant about launch
system design and economics as he is.

Fortunately, few are, and in fact many people know how to do
that--they simply await funding (and some of them are on the verge of
getting it).


Rand, you can keep dismissing what I say and you can keeping saying
what you say over and over - it don't feed the bulldog. Why not just
wait until you have something that works to show?

You're confusing your dreams with reality.

You are the idiot that said:
John Ordover wrote:
The physics problem is that we do not know how, within the laws of
physics, to build a cheap, simple, "model-T" space vehicle that is
affordable to the common man, or even the common corporation.

If it's a problem with physics, what will waiting accomplish? Do you
believe that the laws of physics will change over time in order to
allow a "model T" space vehicle.
The only laws that could actually change to allow a "model T" space
vehicle are laws created by politicans. Waiting for politicans to
change laws which are favorable to opening up Space frontier is
similar to waiting for Hell to freeze over. If people are foolish
enough to assume the problem is based on laws of physics, then they
won't insist that politican change the laws, perhaps meanwhile by
chance, Hell could get slighter colder.

On 8 Aug 2003 19:09:30 -0700, in a place far, far away,
(gbaikie) made the phosphor on my monitor glow in
such a way as to indicate that:

(John Ordover) wrote in message . com...
John apparently believes that everyone is as ignorant about launch
system design and economics as he is.

Fortunately, few are, and in fact many people know how to do
that--they simply await funding (and some of them are on the verge of
getting it).


Rand, you can keep dismissing what I say and you can keeping saying
what you say over and over - it don't feed the bulldog. Why not just
wait until you have something that works to show?

Sigh...what an idiot. Sorry to barge in on your post, gbaike, but
this moron is in my killfile, so I only see him when others (like you)
reply to him.

There is only one way to raise money to build the vehicles required,
which is to persuade investors that there is a market for them, and
that they can be built. Therefore, I continue to do that, both here,
and in private discussions.

On the other hand, if I were to "wait until I have something that
works to show," the goal would never be accomplished, because lacking
funds to build something that works, I would wait, effectively,
forever.

Fortunately, most investors, or at least a sufficient number of them,
will pay no attention to what you say, since you have no credentials,
and can provide no basis for it, other than your mindless mantra about
"not having the needed technology." It is simply the blathering of a
fool attempting to gain attention on Usenet, and most recognize it as
such.

Now, since the reality on places other than Ordover-world is that in
fact such vehicles *can* be built, as any competent engineer who's
studied the problem knows, I will continue to describe that reality,
in order to actually cause the vehicles to be built, and (like all
intelligent people) ignore the pompous ignorance of the Ordovers.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers: