Ethan Siegel has written an interesting article on the success of the Philae lander, and how much more could have been achieved with an alternate power source:
Rather than choosing to make this lander solar powered, we could have chosen, instead to equip it with a nuclear-powered radioactive source. This is proven technology that’s been used in space missions for more than 40 years, including on all the Mars rovers
The article makes the case that the politics, related to unfounded safety fears around nuclear power, have unnecessarily limited the operational life, and the possible scientific payback, of the Philae lander mission.
Quora has a more detailed description of the discussion around this topic.
Spotted via Scientific American's Physics week in review
(Score: 1) by marcello_dl on Monday November 24 2014, @03:30PM
Should Fukushima and Chernobyl power plants have been shopping malls?
(Score: 2) by tangomargarine on Monday November 24 2014, @05:46PM
I live in hope that people will some day stop mentioning Chernobyl and Fukushima in the same sentence as if they were equal disasters. According to Wikipedia, Chernobly radiation levels across the board were 4x as much as Fukushima, and most of the latter went into the sea, not populated areas, anyway.
Stupid nuclear regulatory body and exponential scale putting them in the same category...
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 2) by Jeremiah Cornelius on Monday November 24 2014, @06:04PM
Nuclear probes w/ plutonium payload + Challenger / Orbital Sciences launch failures.
What could go wrong?
You're betting on the pantomime horse...
(Score: 2) by tangomargarine on Monday November 24 2014, @07:20PM
What could go wrong?
As I said in my previous post above [soylentnews.org]:
Considering that the Apollo 13 RTG in their lunar lander which disintegrated during reentry survived intact through all that and a hard fall in the ocean illustrates that these suckers are pretty much indestructible, yes.
So I'm going to go with "nothing." I'd bet a few bucks that if the rocket exploded underneath one of them, the casing would probably just get beat up a bit.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 0) by Anonymous Coward on Monday November 24 2014, @10:34PM
Yes, what could go wrong? What would happen? If you think an RTG on a rocket probe will cause an accident like a reactor meltdown, then you are an absolute dumbass and should not be allowed to participate in this discussion.
Why not toss in a "You can't hug your kids with nuclear arms" or some other irrelevant dipshit statement?
(Score: 1, Flamebait) by kaszz on Monday November 24 2014, @11:50PM
Don't worry, the rocket can provide the opportunity to blowup the core material. And the rest can be blasted by high velocity air braking.
(Score: 0) by Anonymous Coward on Monday November 24 2014, @06:49PM
and most of the latter went into the sea, not populated areas, anyway.
Not populated ... except by our food sources and all the other creatures that live in that water.
Nuclear power is not inherently bad. But we have proven on several occasions that the designs and safety systems are not always good enough. And saying "you can't call Fukushima bad because Chernobyl was worse" is pretty weak.
(Score: 2) by tangomargarine on Monday November 24 2014, @07:26PM
And saying "you can't call Fukushima bad because Chernobyl was worse" is pretty weak.
I swear, you guys make putting words in my mouth a hobby lately. Fukushima was of course a disaster, but it was not *as bad as* Chernobyl. And considering the stupid location they built it in, I'm pretty impressed that it didn't turn out worse.
I imagine there are people around who will use "Fukushima was as bad as Chernobyl" as proof that we haven't gotten any better at managing nuclear plants, which is patently false and damaging, considering our continued bullheadedness about non-renewable power and mortal fear of anything new. There were all kinds of extenuating factors at Fuku and it *still* did a pretty good job of handling it comparatively.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 1, Troll) by pe1rxq on Monday November 24 2014, @07:27PM
Thanks for pointing out the radiation levels have the same order of magnitude. I might have thought they were nothing alike otherwise.
(Score: 2) by tangomargarine on Monday November 24 2014, @07:39PM
Depends what base you use. In binary, 4 is 2 orders of magnitude greater than 1.
In decimal, apparently Chernobyl could be 9.95x Fukushima and they're still "equal." I'm arguing insufficient granularity causing unwarranted panic. (Plus there's all the other extenuating reasons why it happened...on a fault line that had been dormant for 120k+ years...with all power failing and the roads out...)
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 1) by khallow on Monday November 24 2014, @07:52PM
Stupid nuclear regulatory body and exponential scale putting them in the same category...
The scale wasn't exponential, that's just where it stopped. Fukushima would be in the same category as a nuclear accident that cracks the Earth in half.
(Score: 5, Interesting) by nitehawk214 on Monday November 24 2014, @03:31PM
The simple answer is "Yes, it would not have run out of power."
But I think the more complex answer is, "Does the ESA have the technical experience with nuclear powered spacecraft?" Both Russia and the USA have extensive experience with it. (Russia has even flown a fission reactor!) Now, the ESA could have asked their friends to help out, but I wonder if the political issue of anti-nuclear is what really made this decision for them.
"Don't you ever miss the days when you used to be nostalgic?" -Loiosh
(Score: 1, Troll) by q.kontinuum on Monday November 24 2014, @03:43PM
Hey, we have even the Cold Fusion [soylentnews.org] competence here in Europe!!!11eleven11!
Registered IRC nick on chat.soylentnews.org: qkontinuum
(Score: 2) by nitehawk214 on Monday November 24 2014, @05:32PM
Well, it is cold in space...
"Don't you ever miss the days when you used to be nostalgic?" -Loiosh
(Score: 4, Informative) by MozeeToby on Monday November 24 2014, @03:52PM
It's not just about technical expertise or anti-nuclear sentiment. RTGs are heavy and expensive. The fuel is scarce to the point where every mission in which it is used significantly depletes the reserves. Using one of the standard (if you can call things that get run in lots of maybe 3 or 4 standard) designs would have provided either more or less power than the panels, requiring a different science package to get the most out of the setup. What people forget, Philae was a relatively minor part of the mission plan. Finally, the landing was relatively high risk (look at how much went wrong and how easily the landing could have been a total wash instead of the 3/4 success that we got), potentially wasting the limited fuel. And even if everything had gone swimingly, it's unlikely the lander would have survived the comets close approach to the sun when large amounts of material start boiling off the surface.
(Score: 3, Informative) by Kell on Monday November 24 2014, @04:08PM
In fairness, though, part of the reason why RTG nuclear fuel is so scarce is because we have not been making it. The technical process for doing it is well understood and not especially compliacted - just somewhat expensive and requiring specialised infrastructure. However, with the cooling of the nuclear industry and reduction of military investment, we aren't creating the fuels anymore (either as a byproduct or a primary product) and thus our stockpiles are limited. The best way to get more RTGs is to start up a nuclear processing plant and start making fuel; it's just nobody wants to do that.
Scientists ask questions. Engineers solve problems.
(Score: 3, Funny) by VLM on Monday November 24 2014, @04:26PM
it's just nobody wants to do that.
Oh I wouldn't go that far. Maybe we could contract out to Iran?
(Score: 0) by Anonymous Coward on Tuesday November 25 2014, @03:01PM
While an RTG has its technical complexities, the bulk of the power need is simply for heating. It would have been easy to put a radioactive source with no electrical systems in the probe and rely on solar for everything else. This was done to heat the moving parts of Spirit and Opportunity. (The probe would have been able to hibernate without freezing the batteries.)
But as others have noted, the ESA did not have access to the needed Pu at the time.
(Score: 2) by pkrasimirov on Monday November 24 2014, @03:33PM
Given that the comet is closing to the sun, and in fact will go pretty close to it, it's not unreasonable to go photovoltaic. I'm more puzzled by their two battery setup (a non-rechargeable primary 1000 watt-hour battery to provide power for the first 60 hours and a secondary 140 watt-hour battery recharged from the solar panels).
(Score: 3, Informative) by Anonymous Coward on Monday November 24 2014, @04:18PM
I'm more puzzled by their two battery setup (a non-rechargeable primary 1000 watt-hour battery to provide power for the first 60 hours and a secondary 140 watt-hour battery recharged from the solar panels).
The primary mission of the lander was designed to be completed by by that non-rechargeable battery. The smaller battery with tiny solar panels on the lander's body was only added as an extra to allow an extended mission IF conditions permit. That extended mission was to take pictures and stuff like that. And that extended mission was only tacked-on because there were a few extra grams available for those tiny solar panels and the tiny battery.
So what is the point of the discussion about longevity of the craft, when the primary mission was to be done on by that regular battery anyway? Do they have to hammer it into people's heads that the main goals of the lander are already completed? This is not NASA's Mars lander, where primary mission is *years* long. This is not even the smaller landers, where the primary mission were *months* old. This lander's primary mission was to be done with before that 1000Wh battery run out. And it did perform all the tasks it was suppose to do, even though not all of them seem to be 100% success at this point.
(Score: 2) by maxwell demon on Monday November 24 2014, @06:59PM
Combine
with another bit of information from here: [soylentnews.org]
and you'll find that the answer to the question in the title is exactly as Betteridge predicts:
No.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by gman003 on Monday November 24 2014, @03:40PM
Given the knowledge of how the actual mission played out, yes, using an RTG would have been better.
However, without that knowledge, solar was the logical choice. It was a near-sun mission - the expected end-of-life for the probe was when it got too close to the sun to survive. So solar would provide more power for the given weight. Solar is also vastly cheaper than an RTG, given the severe (though politically-dictated) scarcity of plutonium. Also, given the ten-year mission just to get there, there would have been a power decrease of the RTG (not much, about 8%, but still wasted mass).
Finally, many of the instruments were also designed with the requirement that the probe be upright and firmly anchored. An RTG would not have made the probe fully successful, it would just have let us salvage more than we did. So the benefit is not as great as you would initially expect.
(Score: 2) by doublerot13 on Monday November 24 2014, @04:31PM
Seems like solar is way cheaper than nuclear power....and when you are headed for the sun. Why spend the extra money?
I imagine that there was a non-trivial doubt that they would miss the comet anyway. Why risk an VERY expensive craft, when you just risk an expensive one.
(Score: 3, Informative) by khallow on Monday November 24 2014, @04:33PM
2.3 Other Nations - "RTG Technology Is Not Available" Up to date, no other nations launched nuclear powered space missions and litde information is available about corresponding research programs. The American Institute of Aeronautics and Astronautics (AIAA) sums the status up as follows:
"Duringthe 1960s and early 1970s several other nations, including France, Germany, and the United,K.ingdom (U.K.) examined space nuclear reactor power systems. In the 1980s some studies were done by Japan and the U .K. The French government assembled a design team that worked on a reactor concept employing a Brayton cycle to convert reactor heat into electrical power. The French, Japanese, and Chinese now have small programs to explore the use of space nuclear technologies.
Currently the D.S. isnot producing plutonium~238 for space üse, so DoE has been buying some plutonium-238 from Russia to supplement the existing inventory." [AIAA]
The non-availability of RTG technology has quite an impact on space mission planning outside the U.S. and Russia. Themost striking examples are ESA's Rosetta mission to comet Wirtanen and ESA plans for the EuroMoon 2000 mission.
Wirtanen is a comet at approximately the same distance from the Sun as planet Jupiter. This means that the brightness of the Sun at Jupiter reaches about 5% of the brightness at Earth. According to NASA, current solar energy technology is not yet advanced enough to provide enough power for the spacecraft instruments at that distance. ESA, on the other side, had to look for an alternative for their Rosetta mission.
In other words, they didn't consider RTGs because they didn't have access to RTGs at the time. The discussion continues through pages 16 and 17 (there's quotes from a 1994 press release and brief details of the non-RTG-based heating system for Rosetta). Be aware that some words are scrambled. I think it's due to OCR digitization.
(Score: 1) by khallow on Monday November 24 2014, @04:55PM
(Score: 3, Informative) by tangomargarine on Monday November 24 2014, @05:49PM
nuclear worries probably didn't play a significant role
Considering that the Apollo 13 RTG in their lunar lander which disintegrated during reentry survived intact through all that and a hard fall in the ocean illustrates that these suckers are pretty much indestructible, yes.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 1) by darthservo on Monday November 24 2014, @06:10PM
Exactly. It was obviously researched at the time they were discussing the mission. One Ars thread noted that every article with a comment section about Philae seems to have the letters 'RTG' and a '?' in common. Essentially, we have a bunch of armchair engineers. Of course, it is a valid question, but it would be absurd to think that the ESA did not discuss this while developing the mission.
Also as another commenter here pointed out - why set it up with something that could power it for decades? It's very likely that it's going to fry up soon enough. Yet there's still the possibility it could get more light as it gets closer.
Being a visual society it might also be related to the fact we just wanted to see more. A number of other articles/comments seemed to raise the issue with 'Why aren't there color pictures? My phone could do better than that!' My guess is we just wanted to physically see more of what a comet looked like and we likely won't get another chance for decades. (Myself included) But hopefully we don't forget how much data ESA has collected from this.
"Good judgment seeks balance and progress. Lack of it eventually finds imbalance and frustration." - Dwight D Eisenhower
(Score: 2) by cafebabe on Monday November 24 2014, @06:45PM
Idiots. I doubt that a phone launched 10 years ago would have matched the quality of pictures received.
1702845791×2
(Score: 2) by forsythe on Tuesday November 25 2014, @09:23PM
A phone launched ten years ago (or today) would also probably be useless as a result of not having the Van Allen belts for protection.
(Score: 2) by Aiwendil on Monday November 24 2014, @07:25PM
Would it have changed the weight? and would it have caused the lander to stop earlier?
Other than that, RTGs are basically overkill if you don't have to bother with avoiding being detected by other nations or will be close to the sun and outside an atmosphere.. unless you for some reason need insane powerlevels..
Regardless any discussion will only be after the fact - with that knowledge we could also argue that we only should have installed seatbelts in the cars that where involved in crashes (and not installed them in the rest)