. . . and I’m thoroughly unenlightened!

Habitat Hermit, I think it is worth noting in this discussion that the Delta-II is a very complex and expensive booster, and it’s price should not be all that hard to beat. I still think having one technologically and financially conservative choice (OSC, cargo only) to complement the more risky SpaceX proposal is a reasonable decision.

— Donald

Yes, easily. By weaseling.

I didn’t say there was no penalty, just that it wasn’t significant. A plane change out at the distance of the moon doesn’t cost much. I think (though I could be missing something) that it gets lost in the noise of the injection into lunar orbit (or descent). The real constraint is time. Also, I was wrong when I said “any lunar inclination.” I was thinking landing sites, not inclinations, but even for that there are some constraints that can drive delta V. And clearly, if you’re coming in from a high-inclination earth orbit, it’s going to be hard to get into a low-inclination lunar orbit.

Maybe I’ll just quit digging…it’s a complicated subject.

anonymous.space:
that’s an interesting take on it and I’m glad to have read it. I might be wrong in my interpretations but I have some issues with the COTS part of it that I’d like to emphasize/expand upon.

On the COTS decision as noted NASA might have focused on solid finance and Orbital and the Taurus II/Cygnus certainly has that. Not such a bad decision if that is the case. Yes Orbital aims to “duplicate” the Delta II price but look beyond solely the price itself at the rate of launches they’re calculating that price from: an average of two or three launches a year according to the Antonio Elias interview thread over at nasaspaceflight. So that’s a very conservative estimate (by memory they aim to “keep their shirts on” at two launches a year and profit at three).

Also before COTS “1.5” Orbital was already planning and deciding on building the Taurus II/Cygnus on their own (going back to at least June 2007 when they released what I think was their first public sketch –I didn’t feel like digging for the first public mentioning of the project but I think it might be noted in that interview thread) as they were looking for a Delta II replacement for their own uses (shades of Pegasus there). I have the impression they had met their “2-3 a year” target on cost last autumn/early winter before the COTS application but I could be reading too much between the lines on that one. But if that’s true NASA isn’t even the anchor tenant since Orbital itself is (and I bet NASA would love that on assessing the viability of their COTS entry).

However the flight rate is not limited to “2-3 a year” and the COTS deal talks about a potential of 8 launches yearly if I remember correctly (and that’s only ISS). If demand requires it I don’t see why it couldn’t be increased fairly fast including an earlier start on (re-)producing the NK-33/AJ-26 (they’ll have sufficient funds by the time they need it).

Charles:
I like your style (and your Swahili ^_^) but I’ve got some issues with what you write as well. Once again I might very well be wrong.

Flexibility; the Taurus II/Cygnus as it will be built to the best of my knowledge has a liquid first stage and sort of a split second stage with a solid part that gets ditched after use and a liquid part. Antonio pointed out in the aforementioned interview thread that the first stage sort of screams out for a pure liquid second stage and such a stage would likely improve the overall capability by quite a bit (but Orbital including Antonio found it somewhat unnecessary for their own needs). However this can be implemented later on. Then of course there’s all sort of booster options too. Considering this the potential flexibility of the Taurus II/Cygnus should be much larger than the Delta II.

Me stated: “Since it not a plane change, the energy from a more southern launch is more advantages as the “east” velocity component of the final orbit is greater than the component provided by the earth’s rotation at the launch site.”

It’s not so simple an advantage:
A launch vehicle suffers a penalty of sorts for launching closer to the equator than up at the highest latitude of high-inclination orbits because the launch vehicle must fly an westward out-of-plane yaw to kill off any rotational velocity imparted by the spinning earth in order to achieve the desired orbit plane.

Rand, you stated: “You can get to any lunar inclination from any earth inclination with essentially no penalty, other than time.”

Can you explain how to achieve a polar lunar orbit from an equatorial earth orbit without inducing any delta V penalty for the plane change. OR, did you mean Earth’s surface to lunar surface (“inclination” = latitude)?

Actually it’s not completely offtopic because of this part of the press release (also described in the space.com link reader gave):

“The X PRIZE Foundation has also announced that Space Florida will be a new preferred partner and the first preferred launch site for the $30 million Google Lunar X PRIZE competition. Each preferred partner offers additional prizes or strategic services at a discounted rate to all competition teams. As the first preferred launch site, Space Florida will award an additional prize of $2 million to the Grand Prize winner of the Google Lunar X PRIZE competition, provided the winner launched the winning flight from the State of Florida and upon confirmation that the winner has complied with all competition rules. Space Florida was created by the Florida Legislature to sustain Florida’s position as the global leader in space exploration and commerce, and is the principal organization charged with promoting and developing Florida’s aerospace industry.”

(from http://www.xprize.org/lunar/press-release/the-x-prize-foundation-announces-official-contenders-in-private-moon-race)

One of the biggest curses of spaceflight has always been designing for overoptimistic flight rates. It drove Titan IV costs through the roof, drove EELV costs through the roof, and is going to drive Ares costs through the roof. Seeing someone actually design for realistic flight rates is a huge breath of fresh air.

It’s also somewhat refreshing that they didn’t propose manned spaceflight, as I think the odds of NASA actually buying manned spaceflight services are effectively zero unless there are massive organizational changes.

Yes, you’re wrong, or rather, you’re not even wrong.

You can get to any lunar inclination from any earth inclination with essentially no penalty, other than time. But this has nothing to do with the topic at hand…

Interesting point, since one thing Dr. Griffin has been vary consistent on is trying to assage Congressional interests at every turn. It’s too bad he’s so bad at it.

The leading candidate to win is the HTV on an EELV. Look for both Lockheed and Boeing to bid exactly this, and to try to beat the other based on cost.

I’m not sure that this is such a bad outcome. The EELVs need much larger markets than they have, and a successful commercial industry using EELVs might be able to take on the Ariane-V and lead to better second-generation vehicles. The goal, as I see it, is a viable commercial transport system to serve markets in LEO, whether those markets are the ISS or Biglow or trans-lunar injection stages. I’d prefer that SpaceX succeed, but if they fail and we end up with a commercial EELV industry, I think that can still lead to our ultimate goals, albeit more slowly. . . .

Charles in Houston And a launch from Wallops to ISS is cheaper but that does nothing for you if you are going to the Moon. and “me”:

Is that true? Orbital mechanics is certainly not my field, but I thought that if you were headed to the lunar pole, starting from a high-inclination Terrestrial orbit could work. Am I wrong?

— Donald

Launching directly east from KSC, you enter an orbit with an inclination of about 28 degrees.
The ISS orbits at an inclination of 51. 6 degrees

“This means that you must do a plane change of approximately 34 degrees to get from the most economical orbit (from KSC) to ISS…..

Calculations that tell you that the energy used to change inclination is greater than that gained from launching further south.”

Incorrect. No plane changes are made. The shuttle launches at an azimuth that puts it directly in a 51.6 degree orbit. Since it not a plane change, the energy from a more southern launch is more advantages as the “east” velocity component of the final orbit is greater than the component provided by the earth’s rotation at the launch site.