SpaceX announces details on Falcon V

Just saw this:
http://www.spacex.com/index.html?sec...p%3A//www.spac
ex.com/press7.php

Particularly interesting bits:

"The Falcon V also significantly increases the capability of the Falcon
family, with a capacity of over 9,200 pounds to low orbit and up to a
13.1 foot (4 meter) diameter payload fairing. The vehicle is also
capable of launching missions to geostationary orbit and the inner solar
system, as well as carrying supplies to the International Space Station
with the addition of a lightweight automated transfer vehicle.

"With firm contract pricing set at $12 million per flight (2003 dollars)
plus range costs, the approximately $1300 cost per pound to orbit will
represent a new world record in the normally available cost of access to
space for a production rocket"

Cheers,
- Joe

(Let's see, me plus minimal support gear probably comes to 250 pounds,
so about $325K to orbit for me. Still a bit steep, but getting there!)

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| Joseph J. Strout Check out the Mac Web Directory: |
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Joe Strout writes:

"The Falcon V also significantly increases the capability of the Falcon
family, with a capacity of over 9,200 pounds to low orbit and up to a
13.1 foot (4 meter) diameter payload fairing. The vehicle is also
capable of launching missions to geostationary orbit and the inner solar

Does a GEO mission require a new upper stage? Or could it be archived by
just reducing the payload severly with the existing configuration?

My understanding was that a GEO flight profile was significantly different
from anything LEO and requires much longer burn times which may be hard
to get from the same vehicle.


-Andi

In article ,
Andi Kleen wrote:

Joe Strout writes:

"The Falcon V also significantly increases the capability of the Falcon
family, with a capacity of over 9,200 pounds to low orbit and up to a
13.1 foot (4 meter) diameter payload fairing. The vehicle is also
capable of launching missions to geostationary orbit and the inner solar

Does a GEO mission require a new upper stage? Or could it be archived by
just reducing the payload severly with the existing configuration?

My understanding was that a GEO flight profile was significantly different
from anything LEO and requires much longer burn times which may be hard
to get from the same vehicle.

I don't know what SpaceX has in mind here, but isn't it fairly common
these days to put a bird in LEO, with a low-thrust, high-ISP engine
attached that slowly spirals it up to GEO?

,------------------------------------------------------------------.
| Joseph J. Strout Check out the Mac Web Directory: |
| http://www.macwebdir.com |
`------------------------------------------------------------------'

In article ,
Andi Kleen wrote:
"The Falcon V ... is also
capable of launching missions to geostationary orbit...

Does a GEO mission require a new upper stage? Or could it be archived by
just reducing the payload severly with the existing configuration?

Typically, turning a LEO launcher into a GEO launcher (more precisely, a
GTO launcher) requires adding another stage. Apparent exceptions to this
are mostly things that were designed as GTO launchers in the first place.

Just reducing the payload typically is not sufficient, because a good
fraction of the mass injected into LEO is the dry mass of the final stage.
You generally need to add a smaller, lighter top stage. Sometimes it also
does the last little bit of the work needed to get itself into LEO.

My understanding was that a GEO flight profile was significantly different
from anything LEO and requires much longer burn times which may be hard
to get from the same vehicle.

A GTO launch profile is typically more or less a LEO launch profile with
extra burn time (usually from an extra stage) added on the end. A good
many GTO launches, in fact, go via LEO.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

In article ,
Joe Strout wrote:
I don't know what SpaceX has in mind here, but isn't it fairly common
these days to put a bird in LEO, with a low-thrust, high-ISP engine
attached that slowly spirals it up to GEO?

No. Such things have been discussed a lot, but they are not yet normal
practice. (Artemis more or less did this, but that was disaster recovery
rather than a deliberate plan.) One reason for that is that the long,
slow spiral up through the Van Allen belts is very hard on electronics in
general and solar arrays in particular.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

Joe Strout writes:

I don't know what SpaceX has in mind here, but isn't it fairly common
these days to put a bird in LEO, with a low-thrust, high-ISP engine
attached that slowly spirals it up to GEO?

Hmm, I thought you would first need to put it into an GTO from LEO
first for that which requires cooperation from the upper stage. But
maybe it can be all done by an ion engine on the sat.

-Andi

(Henry Spencer) writes:

In article ,
Joe Strout wrote:
I don't know what SpaceX has in mind here, but isn't it fairly common
these days to put a bird in LEO, with a low-thrust, high-ISP engine
attached that slowly spirals it up to GEO?

No. Such things have been discussed a lot, but they are not yet normal
practice. (Artemis more or less did this, but that was disaster recovery
rather than a deliberate plan.) One reason for that is that the long,
slow spiral up through the Van Allen belts is very hard on electronics in
general and solar arrays in particular.


What is common, and may be responsible for the confusion, is to launch
the bird into an elliptical orbit with the perigee above the Van Allen
belts but not quite at GEO, and then use the low-thrust, high-ISP engine
that is already there for stationkeeping to do the last little bit of
circularization. The orbital mechanics for this are kind of strange[1]
and proprietary, but it works.

This requires nothing new and frightening, given that high-ISP engines
for stationkeeping have been the norm for almost a decade, and getting
even a little bit of initial delta-V out of them rather than from the
chemical rockets saves a little bit of propellant mass (couple hundred
kilograms on a high-end comsat) and allows that much more payload mass.

The full spiral high-ISP transfer is now technically feasible, and
would roughly double the payload delivered to GEO by any given launcher,
but it's new and scary and all the major players already have access
to launchers that deliver all the payload they want.


[1] One requirement that complicates the whole thing, is that the
spacecraft always be in an orbit with a 24-hour period so that the
comsat operator doesn't have to cough up the dough for two more
ground stations.


--
*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 writes:


No. Such things have been discussed a lot, but they are not yet normal
practice. (Artemis more or less did this, but that was disaster recovery
rather than a deliberate plan.) One reason for that is that the long,
slow spiral up through the Van Allen belts is very hard on electronics in
general and solar arrays in particular.
--

There have been proposals to use SEP to ferry unmanned payload from earth orbit
to lunar orbit, or up to high orbit for planetary missions. As far as I can
tell, the solar arrays required to make this attractive are much ligher than
current state of the art. Henry, can you comment on this?

Will McLean

In article ,
McLean1382 wrote:
There have been proposals to use SEP to ferry unmanned payload from earth orbit
to lunar orbit, or up to high orbit for planetary missions. As far as I can
tell, the solar arrays required to make this attractive are much ligher than
current state of the art. Henry, can you comment on this?

Not in much depth. :-) What's attractive depends a whole lot on what
assumptions you make, and I haven't looked closely at recent SEP-tug
proposals. To my mind, any such proposal has to envision a long working
life, both for the design and for the individual tugs, to amortize the
development and deployment costs. Otherwise it's easier to just launch
more chemical fuel.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

(Henry Spencer) writes:

In article ,
McLean1382 wrote:
There have been proposals to use SEP to ferry unmanned payload from earth orbit
to lunar orbit, or up to high orbit for planetary missions. As far as I can
tell, the solar arrays required to make this attractive are much ligher than
current state of the art. Henry, can you comment on this?

Not in much depth. :-) What's attractive depends a whole lot on what
assumptions you make, and I haven't looked closely at recent SEP-tug
proposals. To my mind, any such proposal has to envision a long working
life, both for the design and for the individual tugs, to amortize the
development and deployment costs. Otherwise it's easier to just launch
more chemical fuel.


I had a paper on this at the IEPC in Toulouse last year, and one of the
other presenters in the session covered the same ground.

For chemical propulsion, it's never worth bothering with a tug. You wind
up carrying a substantial ammount of propellant all the way to GEO for
the sake of recovering some empty tanks with a bit of useful rocketry
and guidance hardware attached. Easier and cheaper to launch a new bit
of rocketry and guidance each time.

With ion or plasma thrusters, the propulsion system and its associated
power supply are massive and expensive enough that you do want to start
thinking about reusability, and the Isp is high enough that the return
trip involves only a modest propellant cost.

But, it only wins over an expendable upper stage using the same propulsion
technology if you can get six to eight missions out of each tug. Solar
arrays light enough to perform the mission, are presently only known good
for 2-3 slow spirals through the Van Allen belts at most.

Since nobody really wants to hang their business plan on a market six
missions into the future *or* on an unproven new technology in the critical
path, this isn't going to happen any time soon.


However, if you want massively huge (10 tons) payloads in GEO, a space
tug using nuclear-electric propulsion starts to look like the winner.
Strange how nuclear reactors don't mind a high radiation environment.
But, there is no commercial and only a speculative military market for
anything that big.


--
*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 *