Juno development, launch, and cruise, Including Earth flyby imaging Oct 9 2013 Options

[Guest_Geographer_*]

And in the real world with real money and real national interests (that rightfully keep the $190m spend on the Juno LV within the US) ?

Are you interested in science or Boeing's profits? The ESA has no problem contracting certain launches out to Russia. It's not like Boeing is going to go bankrupt if they don't get the Juno launch. It's not like you're contracting the launch to North Korea, Europe is America's ally, and they have an equally capable launch vehicle and better launch position. NASA should take advantage of it if they can.

[djellison]

they have an equally capable launch vehicle and better launch position.

Actually - the Ariane V is a slightly less capable launch vehicle, from a better launch position, resulting in a similar performance.

I'm not going to start ( or allow ) a political debate here - but the fact of the matter is that US tax payers pay their taxes, some of which goes to NASA, so that America can do good science and exploration. As a US tax payer, is one going to be interested in science and engineering jobs in the USA, or in France?

The Ariane V is not significantly cheaper than the Atlas V, and any difference is probably offset entirely by figuring out how much of the cost of an Atlas V launch goes straight back to the US government as income tax.

Yes - ESA and NASA colaborate on projects ( SOHO, STEREO, C-H, JWST ) - but on a trade basis...we'll build a lander, you make the orbiter - or we'll make some instruments to fly, and you can use them sometimes, or we'll launch it if you let us use it for a while..... but NASA writing a cheque to Arianespace for a launch of an American project isn't going to happen, and nor should it. This entire debate is academic as we're now down a road whereby Juno IS launching on an Atlas V- fact. However - were we to wind back history 5 years and have a significant European contribution to the project in terms of instrumentation and scientists - then perhaps the responsibility of launching the mission could become a European affair (as is happening with JWST). Writing big trans-atlantic cheques just makes no sense, for either party, and is not a sensible way to spend the respective taxpayers money.


Doug

[nprev]

Doug's right...plus, of course, it is in the best interests of the US to keep its domestic launch capability afloat. There really aren't all that many launches per year globally, and US commercial interests already outsource a lot of them to Baikonur and/or Ariane, so even one or two domestic Atlas flights become critical to keep the market attractive enough for the big aerospace companies to remain in the business (esp. with the pending demise of the Delta II, which will hurt UMSF). The profit margin here is really pretty slim.

[Greg Hullender]

I notice that Falcon 9 is promising to deliver essentially the same payload to LEO as an Atlas V for the same price as a Delta II launch. If SpaceX truely pulls this off, it seems to me it'll make it hard for the big aerospace companies to stay in the game at all. But it could be GREAT for UMSF. :-)

--Greg

[dvandorn]

But remember, Delta IIs only look cheap in comparison with Delta IVs and Atlas Vs. We're still talking significant expense. The expense of launchers has driven a lot of commercial users to less costly -- and less reliable -- systems.

What we really need is some revolutionary new propulsion technologies that will make access to LEO a lot cheaper than can be accomplished through the sole use of chemical rockets. (And while I'm wishing, I ought to toss in a good thought for World Peace, too, I guess...? )

-the other Doug

[djellison]

I notice that Falcon 9 is promising to deliver essentially the same payload to LEO as an Atlas V for the same price as a Delta II launch.

Falcon 9 is 9.9 to 10.4 tons to LEO

Atlas V is 10.3 to 20.5 (25 if you include the Atlas V heavy) to LEO

So really - the Falcon 9 fits inbetween the Delta II and Atlas V in terms of performance ( something of a sweet spot I would say - MRO took the cheapest Atlas V.a job that could perhaps have been done by an F9 in the future)

Now it gets exciting with the Falcon 9 heavy...27.5 ton to LEO.


Doug

[Guest_Geographer_*]

So the only argument against big checks crossing the Atlantic is national pride? I thought we were part of the larger scientific community. If the Atlas V is the best LV for Juno, so be it. But if the Europeans provide a more suitable vehicle, ie. cheaper and more effective, then why should American taxpayers and the scientific community pay more for less?

Like I said, a single launch is not make-or-break for American rocketry. Science launches make up a small portion of total space launches anyways.

[centsworth_II]

So the only argument against big checks crossing the Atlantic is national pride?

If you make the rocket, why not use it? And if you stop using -- and making -- it,
you may regret it down the line, after it's too late. US business certainly has not
been adverse to exporting other jobs when it helps the bottom line!

[JRehling]

So the only argument against big checks crossing the Atlantic is national pride?

It, along with 99.999% of all human activity, is also a matter of individual incentive. A politician who helps conduct legislation that provides jobs where his/her constituents live is more likely to please those constituents than a politician who watches or helps the same jobs go somewhere else. Ultimately, the money for all of these projects come from taxpayers=voters. They are on average less interested in science than in avoiding unemployment, local recessions, etc.

National federal funding rarely leaves the country in substantial quantities, and it is never highly popular when it does. Likewise, state funding rarely leaves the state it arises in, ditto on other levels.

If you had a single system of government that raised revenues on both sides of the Atlantic, then these considerations would become somewhat less relevant. As it is, they are virtually laws of physics.

[djellison]

So the only argument against big checks crossing the Atlantic is national pride?.

No, national interests.

Pride doesn't enter into it.

I don't think we're going to get any where with this debate. At this point, I'm considering the LV issue closed and any further posts on it will be culled.

Doug

PS: Clearly Geographer can't read what I just posted. Posts culled = 1.

[Guest_Geographer_*]

Is Jupiter the furthest target that a solar powered mission could reach? Jupiter used to require RTGs but advancing solar technology has made those unnecessary, at least for this medium cost mission. How many advances in solar technology can realistically be expected; could there eventually be a Uranus or Neptune mission with solar?

[Greg Hullender]

I'll be surprised if it's ever cost-effective to use solar beyond Jupiter, now that the political opposition in the US to RTG-powered vehicles has largely disappeared. Note that there wasn't a peep about New Horizons using an RTG.

--Greg

[edstrick]

I expect it *IS* cost-effective to use solar beyond Jupiter.... for very "quiet" missions. You basically need solar-sail concentrators aimed at solar panels. Not the sort of thing to easily and accurately deploy from a folded-for-launch configuration. But very deep space observatories doing things like low frequency radio work or interplanetary weather stations or other spacecraft that do not do extensive maneuvering, especially attitude changes, could relitively easily use solar power. These might be assembled/deployed in high earth orbit... L5 or whatever, and sent outbound with ion engines.

[vjkane]

There have been several proposals for a Saturn atmospheric probe mission in which the carrier spacecraft is solar powered. I believe that the mission is New Frontiers class.

I once calculated the energy available at Uranus for a craft using the largest solar arrays flown on interplanetary spacecraft. It was harder to figure out than the simple geometry of light intensity loss because solar arrays can be tweaked to perform better under (if I recall correctly) different temperature ranges. (It may have been different light levels; this was awhile ago.) I even doubled the size of the arrays. No go -- just not enough light.

However -- the new stirling low cost nuclear power supplies that NASA is considering for Discovery missions probably would enable a small Uranus craft with a probe or two in terms of power. The cost would probably still fill a New Frontiers budget. I suspect that you would still need a battery to handle peak power demands.

I am admitting that I am having problems thinking of missions within a Discovery price tag that would be *enabled* by the Stirling power supply. I can think of several -- network landers on Mars or rovers on Mars -- that would be easier with such a power supply. However, my understanding is that there are fairly few missions that need just 100-200W of power (I forget the exact power offered by this generator) and that don't require expensive launchers such as anything going to Jupiter or beyond. Perhaps I'm just not clever enough.

[nprev]

I'll be surprised if it's ever cost-effective to use solar beyond Jupiter, now that the political opposition in the US to RTG-powered vehicles has largely disappeared. Note that there wasn't a peep about New Horizons using an RTG.

--Greg

Noticed that too, and was pleasantly surprised; it's absolutely key.

I think that even if solar cell efficiency increases ridiculously (think it's around 40% right now), RTGs are still the only game in town for outer-planet missions. The recent ISS array deployment difficulty shows how much risk there is with very large arrays for UMSF (and no way to fix them, unless you get really lucky with respect to failure mode). Furthermore, all the articulation needed to maintain optimum power levels after achieving orbit around the target not only adds weight & even more mechanical complexity, but also requires a lot of power to accomplish; motor torque eats current like so many peanuts.

When you're talking very infrequent launch opportunities combined with decades of cruise time for Uranus & Neptune, I don't think we want to roll those dice...