NASA Cancels RTG Research Program

[Kryten]

And then let's take all of the funding from the world's militaries and use it to buy ponies and sweets.

[PakledHostage]

Stirlings seem to be one of those technologies that pop up every few years in another new context and show lots of promise, but never really come to anything.

A bit OT, but I have a sterling engine on my desk at work that runs off the heat of a cup of coffee. If my experience is any indication, then they show a lot of promise as an efficient conversation starter...

[goldenpeach]

Where have you found it?

Also,(if it's not too personal) for what do you use it?

[PakledHostage]

What do I use it for? For starting conversations! Q.E.D.

I got mine as a gift so I don't know how much it was or where they got it from, but you can find lots of examples online.

For example: http://www.stirlingengine.co.uk/d.asp?product=KS90_BLA_ASS

[goldenpeach]

ok,thank you for the answer(and for the link)!

[RuBisCO]

The DOE is on behalf of NASA is to have production ramped up to1.5-2 kg of Pu238 per year by 2018. How long would it take to have enough Pu238 for a MMRTG, well each one requires 4.8 kg of plutonium, so just 2.4-3.2 years to make 1 MMRTG. New Horizon manged with modern high efficiency electronics a deep space mission on 240 W, so lets say we would need 3 MMRTG tops for say a Europa orbiter or something would mean it would take 7.2-9.6 years to scrounge up enough PU238 for said mission, We would be limited to about 1 deep space mission a decade, which is about what we are doing anyways. Of course with ASTG we could do 4 mission a decade but we clearly don't have the money for that. Each one of these missions cost at least hundreds of millions, usually billions of dollars, a few million saving on Pu238 per mission is just not worth it.

[SargeRho]

We really need small-sized/light-weight nuclear reactors for space use. Didn't someone recently build a small uranium reactor that could even be used for manned craft?

[3_bit]

Well, our way into space is gone, so this really isn't that bad. The Constellation Program was our future for space travel, and the Space Shuttle is gone with no replacements in sight. NASA might as well be shutdown, and have private contractors handle Curiosity and the others. Let's face it: chances are the US will not be the first to Mars, nor to establish a Lunar base (I almost typed Munar). This is a sad day, but that fateful day when Constellation was shelved was worse.

[RuBisCO]

We really need small-sized/light-weight nuclear reactors for space use. Didn't someone recently build a small uranium reactor that could even be used for manned craft?

Development cost money, money we don't have due to the present political atmosphere, and likely will not have for many years if not decades.

Well, our way into space is gone, so this really isn't that bad. The Constellation Program was our future for space travel, and the Space Shuttle is gone with no replacements in sight. NASA might as well be shutdown, and have private contractors handle Curiosity and the others. Let's face it: chances are the US will not be the first to Mars, nor to establish a Lunar base (I almost typed Munar). This is a sad day, but that fateful day when Constellation was shelved was worse.

Constellation was doomed before it even began, there was no chance congress was going to funded it to the levels it needed and that is exactly what happened. Griffin made a huge mistake for asking for a Apollo like program in an political atmosphere that could not possible have funded it. Griffin should have focused on a DIRECT type booster to replace the space shuttle, reusing as much of the original space shuttle hardware as possible (minus the space shuttle of course) to minimize price. Constellation would have created two rockets, one with 25 tons to LEO capacity and the other with 188 tons to LEO capacity, need new lengthen strap on boosters, new wider and longer fuel tank, new engine array, new upperstage, new lunching pads. In the end the cost was far FAR too much for NASA present budget and congress did not fund it, and the president killed it, for the completely predicable, logical, acceptable reason it was too costly. DIRECT type booster would have made just one rocket with far less modification to shuttle infrastructure for a starting out launch capacity of 75 tons to LEO, with future upper stage bring that up to 120 tons to LEO. Griffin failed to learn from the very important lesson he himself derived from the Saturn V to Space Shuttle story: don't drop what you have for what you think you could get, when dozens of billions of dollars are on the line! The space shuttle was built on the belief it would make launch prices much cheaper, it turned out to cost twice as much per mass to orbit as the Saturn V (with or without development cost included) and left us trapped in low orbit. If we had simply stayed with the Saturn V instead of dropping dozens of billions of dollars of hardware and infrastructure just to spend all that again and more to build something that turned out to be a total failure in costs, capability and safety (space shuttle) we likely would have had enough money left to have built bases on the moon and been to mars already. Yet Griffin did not take his own lesson to heart and proposed nearly completely rebuilding the space shuttle hardware, and it predictably failed. Now with the space shuttle infrastructure mothballed and scraped even a DIRECT type booster that is the SLS will likely cost too much.

Edited November 17, 2013 by RuBisCO

[mdatspace]

Well, our way into space is gone, so this really isn't that bad. The Constellation Program was our future for space travel, and the Space Shuttle is gone with no replacements in sight. NASA might as well be shutdown, and have private contractors handle Curiosity and the others. Let's face it: chances are the US will not be the first to Mars, nor to establish a Lunar base (I almost typed Munar). This is a sad day, but that fateful day when Constellation was shelved was worse.

Constellation was over-budget and behind schedule. The space shuttle was 1.5 B per launch and failed at its objective:to make space cheap.

But this is bad. It would have greatly helped exploration of the outer solar system. It uses much less PU-238 than normal generators for the same power.

Edited November 17, 2013 by mdatspace

[SargeRho]

Found it: http://www.popsci.com/technology/article/2012-11/los-alamos-lab-builds-fission-reactor-future-space-travel

That's the small reactor I meant. It runs a set of stirling engines that in turn run generators.

[Parax]

Like what?

Other elements can get 'hot' too, some need minor activation. 232.03806

[Parax]

What do I use it for? For starting conversations! Q.E.D.

I got mine as a gift so I don't know how much it was or where they got it from, but you can find lots of examples online.

For example: http://www.stirlingengine.co.uk/d.asp?product=KS90_BLA_ASS

These Stirling engines are fantastic too.

[Nibb31]

The problem with Stirling engines, as previously stated, is that it has moving parts. Those are bound to fail at one point. Bearings, axles and pistons don't last forever. They wear and tear and need lubrication, seals, and constant adjustment.

[RuBisCO]

http://local.ans.org/trinity/files/mcclure-130920.pdf

yes impressive, starting at 400 kg for a 800W electric reactor, no moving parts other then the control rod and Stirling generators. I'm sure with coolent pumps and broyton cycle they could achieve much better mass to weight ratios, at the cost of added complexity and risk. I would think though I we had made a concerted effort since the 1960's to build and fly kilowatt and even megawatt class nuclear power plants in space we would have reactors which many times the power/mass performance of these yet with a record of years-decades of reliable service.

In short technology does not advance without significant investment and in the in the field operation.

The problem with Stirling engines, as previously stated, is that it has moving parts. Those are bound to fail at one point. Bearings, axles and pistons don't last forever. They wear and tear and need lubrication, seals, and constant adjustment.

Thermalelectrics don't last forever either, they slowly degrade in performance over time as microcracks form in the metal and metal-metal interfaces. Its just this decay is predicable unlike a mechanical failure. The question is can a Stirling be made to operate reliable for 14 years, even in deep space? The answer it most likely yes, the results from the ASRG experiments were certainly in that direction, all that was needed was further testing, but alas funding cuts.

Edited November 17, 2013 by RuBisCO

[Skyrunner27]

The space shuttle was built on the belief it would make launch prices much cheaper, it turned out to cost twice as much per mass to orbit as the Saturn V (with or without development cost included)

Can I get a source for this. The only place I found a similar statement was on another form. That is not the most reliable source. Not saying your lying but I would rather have more than your word on it.

About the rest of the this thread. I do think it was a bit stupid to cancel a project near completion. I don't really have a opinion on the SLS vs. Constellation issue, but I do think they should have kept developing the Ares 1 being that we already had one fly. Also this Gap is still not larger than the one between Skylab 4 and STS 1

Edited November 17, 2013 by Skyrunner27

[SargeRho]

The actual launch cost is 450 million, but the program cost divided by number of flights is 1.5 billion or so.

At 450 million per launch for a 25 ton payload, it's around 18000$ per kilogram. At the 1.5 billion tag it's even worse.

By comparison, it's about 4000$ per kilogram on a Falcon 9 at max payload I think. Similar thing with the Soyuz program.

[thunderstar]

dont worry guys, im sure things will work out fine in the end, "we may be having a little storm right now, but im pretty sure the sun will come again sooner or later" these budget cuts will end someday, maybe not tomorrow but soon indeed

[Kryten]

Can I get a source for this. The only place I found a similar statement was on another form. That is not the most reliable source. Not saying your lying but I would rather have more than your word on it.

According to this article in nature the total cost of the space shuttle program was $196 billion, adjusted for inflation. Divided over 134 flights, that works out as $1.4 billion per mission. The equivalent cost for Saturn V (adding up the items here and adjusting for inflation) is $47 billion; divided by 13 flights, that's $3.6 billion per mission. Space shuttle took ~25 tons payload to LEO, Saturn around 120 tons.

[magnemoe]

The actual launch cost is 450 million, but the program cost divided by number of flights is 1.5 billion or so.

At 450 million per launch for a 25 ton payload, it's around 18000$ per kilogram. At the 1.5 billion tag it's even worse.

By comparison, it's about 4000$ per kilogram on a Falcon 9 at max payload I think. Similar thing with the Soyuz program.

Multiple reason why the shuttle was so expensive, one reason is that it was an hangar queen, design was so hard stressed it took a lot of maintenance to keep it running. Part of this was that the upper stage was very heavy, around 75 ton or something dry weight, so unlike an normal rocket where the dry mass of the upper stage is less than the cargo here it was three time as much.

However the shuttle was able to do far more than launching satellites but this does not help then it was to inefficient to do that.

The maintenance and launch cost reduced the numbers of shuttle launches and this caused the costs to snowball hard as you still needed all the services around it.

[Nibb31]

Can I get a source for this. The only place I found a similar statement was on another form. That is not the most reliable source. Not saying your lying but I would rather have more than your word on it.

Wikipedia says this about Saturn V:

From 1964 until 1973, a total of $6.5 billion ($46.77 billion present day) was appropriated for the Saturn V, with the maximum being in 1966 with $1.2 billion ($8.63 billion present day).[46]

One of the main reasons for the cancellation of the Apollo program was the cost. In 1966, NASA received its biggest budget of US$4.5 billion, about 0.5 percent of the Gross domestic product(GDP) of the United States at that time. In 1969, the cost of a Saturn V including launch was US $ 185 million (inflation adjusted US$ 1.18 billion in 2013).[47]

and this about STS:

The actual total cost of the shuttle program through 2011, adjusted for inflation, is $196 billion. The exact breakdown into non-recurring and recurring costs is not available, but, according to NASA, the average cost to launch a Space Shuttle as of 2011 was about $450 million per mission.

So, the total program cost was equivalent to $46 billion for 13 flights, which equates to $3.5 billion per flight for Saturn V.

And the total program cost $196 billion for 135 flights, which is $1.5 billion per flight for the Shuttle.

It's all apples and oranges though, because the capabilities and the number of flights are vastly different.

No doubt the cost of a Saturn V would have been streamlined if the program had continued. On the other hand, its development also shared a lot of common design with previous Saturn rockets.

Some people argue that the Shuttle was more capable, but most of that capability ended up being either useless (like crossrange) or simply not economically viable (like retrieving broken satellites or on orbit repairs). All in all, the problems that it solved were either not problems at all or had easier and cheaper solutions anyway.

More importantly, the Saturn V could launch ~100 tons to LEO, whereas STS could only launch 20t. You would need 5 STS launches to launch the equivalent of a Saturn V payload. In fact, the entire weight of the ISS could have been launch with only 4 Saturn V flights instead of 27 shuttle flights and a couple of Protons.

Therefore in terms of cost per ton to orbit, the Saturn V at $35 million/ton crushes the Shuttle's $75 million/ton. But then again, so do modern commercial launchers which are in the order of $10 million/ton these days.

Edited November 18, 2013 by Nibb31

[RuBisCO]

Can I get a source for this. The only place I found a similar statement was on another form. That is not the most reliable source. Not saying your lying but I would rather have more than your word on it.

It simple math: take the price of a Saturn V per launch, divide by its payload capacity, now take the price of a Space Shuttle per launch, divide by its payload capacity, compare these two numbers.

The space shuttles cost $450 M per launch (not including development costs) (2011 dollars) and could lift at most ~25 metric tons to orbit, so that is ~$18,000 per kg...

The Saturn V cost $1.18 B (not including development costs) (2013 dollars) and could lift ~120 metric tones, so that is $9830 per kg.

You can find a all this on wikipeida including citations to primary/secondary sources.

http://en.wikipedia.org/wiki/Criticism_of_the_Space_Shuttle_program

http://en.wikipedia.org/wiki/Saturn_V

The Saturn V was also do for upgrades with Uprated F-1A Engines and stretching first stage bring lift capacity to 137 tons, stretching of the second and third stage with new J-2S engines would have brought that up to 160 tons. All of this was already developed and test by the time Saturn V production was canceled and would not have added much to the cost, meaning even better $/kg numbers.

There was also developments into downsizing the Saturn V. For example Skylab was basically a Saturn V with no 3rd stage, or basically the Saturn INT-21 proposal implemented. Other plans called for removing the 2nd stage, removing 0-2 engines from the first stage and launching just the first and "3rd" stage together (Saturn INT-20) with capacity between 45-60 tons to LEO. There was many possibilities from there for example a shorten first stage with just one F-1A and "3rd" stage with 20-25 tons capacity could have replaced with Saturn IB construction line completely.

There is no telling how low this line of Saturn V based rockets (including the good old Saturn V) could have got with ~40 years of production behind it, Soyuz rocket is a good example of where decades of establish infrastructure and incremental upgrades can go.

Edited November 18, 2013 by RuBisCO

[Skyrunner27]

Okay, I get it now. Thanks.

[RuBisCO]

Well if it comes from spaceflightnow.com its official: http://spaceflightnow.com/news/n1311/19asrg/#.UoyTZOKZj3A