New heavy lifter?

On Tue, 27 Jul 2004 10:07:19 -0400, "Jeff Findley"
wrote:


There is more than one way to skin this cat. It may prove cheaper to launch
comsats that can be refueled during their lifetime than to launch them with
all their fuel. Such a fuel delivery system would be much lighter and
smaller than launching the comsat itself. Such a solution would not require
even bigger launch vehicles.

HOW would you refuel the things? Would the comsat owner REALLY want to
risk his sat being wrecked by docking maneuvers?

wrote:

There is more than one way to skin this cat. It may prove cheaper to launch
comsats that can be refueled during their lifetime than to launch them with
all their fuel. Such a fuel delivery system would be much lighter and
smaller than launching the comsat itself. Such a solution would not require
even bigger launch vehicles.


HOW would you refuel the things? Would the comsat owner REALLY want to
risk his sat being wrecked by docking maneuvers?

If the satellite costs were dramatically lower, and the choice was that
or running out of propellant, why not?

wrote in message
...
On 27 Jul 2004 03:57:15 -0700, (Dave O'Neill) wrote:

MLV seems to be arriving as a consequence of
needing ever larger switches in GEO.

MLV?

Medium range - no firm number but 40,000kg to LEO is typically quoted.

Dave

"Rand Simberg" wrote in message
.net...
Dave O'Neill wrote:

Really? And what do "most" people consider it?

The O'Neill vision (Gerard, not Dave).


Which was funded on, what at the time, seemed to be a rather sensible
proposition.

Which include *thousands* of people living and working in space. This
is a fundamental feature of it.

I don't think that we would

consider California "developed" if it was nothing except robots growing
agriculture and mining gold.


And that has what to do with this?

You are proposing "development" without any human population. I'm
pointing out the nonsensical nature of such a proposal.

No, actually I'm not. That's what you think I mean.

I'm suggesting that space can develop, including humans but not along the
lines you think it should.

Dave

Dave O'Neill wrote:

You are proposing "development" without any human population. I'm
pointing out the nonsensical nature of such a proposal.


No, actually I'm not. That's what you think I mean.

I'm suggesting that space can develop, including humans but not along the
lines you think it should.

Of course it can, but not until access to it gets much lower cost.

"Rand Simberg" wrote in message
. net...
wrote:

There is more than one way to skin this cat. It may prove cheaper to
launch
comsats that can be refueled during their lifetime than to launch them
with
all their fuel. Such a fuel delivery system would be much lighter and
smaller than launching the comsat itself. Such a solution would not
require
even bigger launch vehicles.


HOW would you refuel the things? Would the comsat owner REALLY want to
risk his sat being wrecked by docking maneuvers?

If the satellite costs were dramatically lower, and the choice was that
or running out of propellant, why not?

Which just serves to point out the current chicken and egg problem of high
cost comsats coupled with high cost launch vehicles. Because the launch
costs are so high, comsats had *damn well* better work right and had better
last a long time. Because of this, comsat designs are very conservative and
would not risk their "investment" on an "untested" procedure like automated
rendezvous and docking followed by automated fuel transfer (never mind that
Progress essentially does this on every flight to ISS).

If launch costs were lower, you could build cheaper comsats because you
could tolerate some failures. You could try new solutions to problems like
life extension of operating comsats that are running low on fuel.

But the comsat industry will not provide the drive to get us cheap access to
space. They are already far too conservative and are willing to live with
today's launch costs. This is why so many people are starting to push for
"space tourism" as the driver for change in the industry. People demand low
ticket prices because it's their money!

Jeff
--
Remove icky phrase from email address to get a valid address.

Dave O'Neill wrote:

I'm not sure that's quite fair. Based on the industry speculation
I've been seeing, the market for large GEO com sats is increasing
dramatically, and the current limits will not be particularly
acceptable for much longer.

But why would you go with a Delta 4 upgrade an not one of the proven
existing solutions,


The trouble is, it's not a massive market. It probably will be
enouugh to fund continued development and maybe even a Ariane 6.
There are spin off uses, however, you could always go to the Russians
for some of this capability if it was that important.

I would expect Ariane 6 to be relatively far away and not be developed
before there is a serious need for low-cost heavy launcher - just looking
back at Ariane 4 and looking at the Ariane 5 upgarde path, I don't see
an iminent need for Ariane 6.

I would also not be suprised if there was an intermediate version that
combined say Ariane 5 with rail launch. Possibly in two configurations,
boosterless and with boosters for different preferences of cheap vs. heavy


Yes. But we could do quite a lot with existing hardware and only
slight developments. There's plenty of profiles for Proton based
manned moon missions. You could certainly service a small moon base
with a Proton class vehicle.

No - if you want to have a moon base, you need a lunar supply barge,
which would probably be approx. ATV style ion thruster freight carrier,


Expanding that would be tricky, but it could be more than Flags and
Footprints.

Slow expansion need not really require extras over maintenance.


Dave

--
Sander

+++ Out of cheese error +++

In article ,
Jeff Findley wrote:
Still another solution is assembly in LEO from multiple pieces, which are
then sent into GEO. If CATS really does arrive, what's to stop you from
launching a comsat in half a dozen pieces, plugging them together in LEO,
then sending it to GEO on a resuable "tug" that's refueled in LEO?

In fact, you don't need to assemble the comsat itself. About a 4t payload
into LEO will lift the biggest comsats with a full load of stationkeeping
fuel (assuming your tug delivers all the way into GSO, so the comsats
don't need fuel for an apogee burn). You would launch the tug (if not
reusable) and the fuel first, and the comsat last, because getting the
comsat up and on its way quickly minimizes the time for power and thermal
issues to become problems.

Mind you, the cargo bay would have to be a good deal larger than that of
current launchers with that payload.

Even fueling the comsat itself in orbit will need design changes and
probably some orbital infrastructure. Assembling it in orbit will need
both. Mind you, it's what the customers will eventually want -- life
would be a lot simpler for the designers if the hardware could go up in
shipping containers and get final assembly and checkout in orbit, never
having to deal with the launch environment fully assembled -- but that
level of change will take time. It's a very conservative business.

Reusing the tug is a bit of a challenge: coming back from GSO is costly,
even with aerobraking (which has its own problems, notably the Van Allen
belts). A low-up-front-cost business plan would start with an expendable
modular tug, and contemplate reusability later.

...there is conceptually a middle-ground between smaller
"Iridium" style solutions and the large comsats launched into GEO. Part of
the reason that no one tries any solution other than large GEO comsats is
the price. At today's launch costs, even "Iridium" style solutions are
expensive.

Moreover, there's no question that there *is* a significant market for an
Iridium-style system... if it's got the performance to equal cell phones.
A large part of Iridium's problem was slow implementation, during which
customer expectations got raised.

The phone needs to be not much bigger than a modern cell phone -- in fact,
it should double as a cell phone -- with battery life not too much less,
and it needs to work indoors. There's nothing impossible about this, it
just needs a whole bunch of big powerful LEO satellites with big antennas.

And the calls need to be reasonably cheap. Which means that the large
constellation of big satellites can't be too expensive.

There wasn't much *technically* wrong with Iridium that vastly cheaper
launches couldn't have solved.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Robert Kitzmueller wrote:

Mike Atkinson wrote:


EOR, docking (not construction or fuel transfer) and ~20T modules
(propulsion and various payloads) seems a better way. No costly HLV
or orbital infrastructure. It is probably not as efficient from an
initial mass in LEO point of view and has more complex operations
than a single HLV, but it is more flexible and with multiple launcher
types (EELV, A5) is robust to launcher failures.


This proposal looks a lot more useful than Jeff Fousts Tankfarm
approach. Docking of 20t modules is no great leap into the unknown,
considering MIR and Salyut 7.

But why must the cap be at 20t? Commercial launchers get bigger and
cheaper, even if business is very cyclic. 2015 (the date named by GWB)
is far enough away that one more cycle could have happened, with
bigger launchers than now available desperatly looking for customers.
(Like NASAs moon mission). And since the Apollo craft was heavier than
necessary, a simple mission could be launched using something not much
bigger than commercial available - that is, in 2015-2020, not in 2004.

Robert Kitzmueller

My reasoning is that we know that ~20T enables a useful payload after
docking connectors and other necessary attachments are taken into
account, 10T is probably too small. What is required is that smallest
size that enables a high flight rate, good mass efficiencies and
reasonable operations. Docking 5-10 modules for a mission seems possible
but more than that would start getting unwieldy.

Greater than 20T modules would obviously be possible, but there are no
current LV that could launch them. Although I haven't done the maths my
gut feeling is that 5 or 6 propulsion modules would be required to place
one payload module on the moon. A mission to Mars might require 10
propulsion modules and 2 payload modules.

Yes, commercial payloads are getting bigger and launchers are increasing
in size to cope, but the latest ones EELV and A5 are both fairly new and
so I don't expect significant further increases in the next 10 years. No
doubt engineering tweaks will improve their performance a bit but not
enough to make a difference to my analysis. There are far too many
launchers going after the current market, this makes it hard even for
governments to allocate large amounts for capacity improvements.

--
Mike Atkinson
(to reply remove NO SPAM)

Rand Simberg wrote:
Dave O'Neill wrote:

no space development doesn't follow from no CATS - only no development
directly involving humans does.

What would be the point of that?


From a business perspective there's enough to create a multi-billion
dollar industry. Imaging, weather, communications and so forth all
seem to be doing rather. MLV seems to be arriving as a consequence of
needing ever larger switches in GEO.

That's not what most people consider the "development" of space. And
we're already doing all of them.

Really? Why would people not consider activities that result in infrastructre
in and for space to be space development?

--
Sander

+++ Out of cheese error +++