Kerry and NASA

[bobvanx]

<font color="yellow"> The only things you've argued are that powersats generate considerably more power for a given area</font><br /><br />Yes, well, I'm taking things one step at a time, in between trying to get some real work done so I can keep my home economy moving towards unity.

 

[mrmorris]

<font color="yellow">"Space Based Solar has enough high-qualilty sites to provide the U.S. with 300% of its electricity needs. <br /><br />There's the part of the equation that, in my analysis, trumps all the others: cost, feasibility, risk... "</font><br /><br />No. It doesn't. <br /><br />Let's work some more figures here. You used a 1.2 GW powersat in your earlier discussion for a power of about 1GW at Earth.<br /><br />Solar PV groundside currently costs about $10/installed watt. A groundside PV farm in that range then would cost about 12 billion dollars. Lifting the same to a geosync orbit, plus humans to put it together presumably -- robots aren't cutting it for some time to come, plus your rectenna will increase that cost by another order of magnitude to 120 billion dollars.<br /><br />For 12 billion dollars, you could install 12 GW of wind farms. <br />For 120 billion dollars, you could install 120 GW of wind farms.<br /><br /><br />So how is this helping the US again? Ignoring the cost because you really really like powersats is... unwise.<br />

 

[bobvanx]

I got a little bit of work done, the older child made dinner, the house is settling...<br /><br />I decided to review some of what I know, and came across this. I know, you want me to address the expense. But we're not to that part of the conversation yet. So here's part of that Really Big Picture I mentioned we'd have top wrap our heads around, in order to have SPS leap off the page. I lifted this from http://www.sciscoop.com/story/2004/1/8/204529/3366<br /><br /><hr /><br />Finally, to sum it all up: <br /><br />(1) Human-generated CO2 and the associated global warming is a big problem for the coming century, although there are some engineering strategies that could (with other side-effects) mitigate it. <br /><br />(2) We're going to be running out of fossil fuels anyway in the next few centuries; without alternatives, global economic prosperity will be endangered much sooner than that. <br /><br />(3) Depending on how far efficiency improvements can get us, the mid-century energy requirement from non-fossil sources is between 9 and 30 TW(thermal), or 3 - 10 TW (electric), year-round. <br /><br />(4) No current renewable technology can provide that power level for less than about $10 trillion in capital investment. <br /><br />(5) The best plan seems to be an adaptive one: introduce a carbon tax and technology incentives of all sorts for the renewable options, and then adjust both taxes and incentives in response to changing assessments of CO2 damage and non-fossil technological promise. <br /><br />(6) Wind may be ready for large scale installation; however investments are needed in energy storage and transmission technologies to make it really practical. Biofuels are already in large-scale use: R&D investments to improve their efficiencies, perhaps including genetically engineered crops, should be supported. Solar is a little further away, but R&D there should be strengthened because of th

 

[nexium]

Thanks for bringing up SPS = solar power satellite. I love to analyze. An important consideration is most communities need about twice as much electricty near sunset as the average for the rest of the day = the peak demand period. This is about the time surface solar stops making electricity. Like nuclear, geo-stationary SPS has the same output 99% of the time, so costly polluting, gas turbines are run about an hour per day to make the extra power for peak demand and rare down time emergencies and maintenance.<br /> If we orbit the SPS at about 1/2 the GEO-sychronous altitude, the satellite stays over the sunshine terminator, or close by. This is called a solar sychronous orbit. Closer means the transmitting antenna on the satellite can be smaller, saving perhaps 100 billion dollars construction cost. This SPS beams the energy to the communities where it is needed most. I believe the transmitting antenna can be designed to produce three beams up to 1000 miles apart, each separately steerable and of equal or unequal power. This may make the SPS practical up to about two gigawatts = 2000 megawatts where the cost per megawatt-hour may be least.<br /> There are, of course, other considerations: More rectennas are needed which are typically only used an hour or two per day. Very costly but it does allow other uses for the square mile plus perhaps 22 hours per day. There will be brief periods when the SPS is over the Atlantic or Pacific ocean, when only a small portion of the 2000 megawatts can be safely sent to a rectenna. Co-operation of many countries will be needed as the rectennas are needed in nearly every tropical and semi tropical nation. The SPS can swing briefly away from the Equator in a semi polar orbit, but I think that will mean one, likely more, days per month that the SPS will be too close to the horizon to safely beam the needed amount of electricity to a rectenna in the temperate zone. I have not been able to think of a quick way to turn off the 2000 megaw

 

[nexium]

Suppose we build a twelve square kilometer array in solar-sychronous orbit = 3 KM by 4 KM. We average 1250 watts of sunlight delivered to the average square meter = 15 gigawatts. We get 5.1 gigawatts of low voltage dc. Mrmoris is correct and that is 34% efficiency which is a very optimistic projection of future efficiency. I fear the following numbers are also optimistic. We connect about a million solar cells in series to get one million volts; many series strings in parallel to get 5000 amps = 5 gigawatts which we send on many parallel conductors over a ten kilometer umbilical cord to the antenna array (which must point at the rectenna instead of at the sun) which has 4500 kysitrons, ten to a series string operating at about 90,000 volts each. these produce 2300 megawatts of microwave energy, which can be feed to 4500 dipoles which radiate 2000 megawatts toward Earth with the help of perhaps 30,000 passive antenna elements, or a big dish about 3000 meters in diameter. 1500 megawatts reaches the three rectennas. 400 megawatts is scattered about the solar system. 100 megawatts is scattered in Earth's atmosphere. 50 megawatts is scattered back into space. The dipoles of the 3 rectennas produce 1000 megawatts of low voltage dc. 1000 dipoles in series drive an inverter which produces 60 hertz ac. 800 inverters in series produce 500,000 volts for the high tension line which is part of the grid. Other series strings of inverters produce the other two phases of the 3 phase power line. Many series strings are in parallel at each of the three rectennas to total perhaps 800 megawatts put on the grid. Transformers can be used to avoid inverter outputs in series, but the transformers loose another ten or twelve percent of the power, as they must have very high voltage insulation, and thousands of primaries are needed for the thousands of inverter outputs.<br /> If most of the customers live within 50 kilometers of the 3 rectennas, perhaps 600 megawatts is used by the customer

 

[nexium]

Hi bobv: Tell us about the powerTube for geothermal. We likely should be harvesting geothremal energy in Yellowstone park, with a ten cent per kilowatt-hour subsidy and additional funds to reduce the damage to the sightseeing. Removing energy may delay or weaken the next big blow up of this super volcano.<br /> I don't think anyone can be persuaded to get geothermal from the Mount St. Helens caldera, with erruption likely days away, but it might be possible to extract 1000 megawatts before it blows.<br /> My guess is a thermocouple array at the bottom of an average capped oil well would yield 100 watts, but halve daily to less than one watt as rock is a poor thermal condutor. Neil

 

[mrmorris]

<font color="yellow">We average 1700 watts of sunlight delivered to the average square meter = 20 gigawatts. We get 5.2 gigawatts of low voltage dc. "</font><br /><br />Solar flux in earth orbit is 1300 watt/m2.<br /><br />12,000,000 m2 * 1.3 kW/m2 = 15,600,000 kW = 15.6 GW.<br /><br />Your calculation assumed 26% efficiency solar cells which would result in 4 GW of DC produced by the PV array.<br /><br /><br />Since apparently there's a need to really get into some hardish figures on this SPS thread. I used BP's BP5130L panel to get weight and cost information. It produces about 133 watts/m2 peak power. This works out to about a 13.3% efficiency (lower than ideal rates, but closer to current real world ones). It makes the solar powersat in question generate about 2 GW.<br /><br />The panel weight works out to ~13kg m2. For a 12 sq km powersat this works out to ~156,000,000 kg (ignoring the need for a support structure completely). At a ridiculously low cost-to-orbit of $1,000 per kg -- the costs <b>just</b> of getting these cells to orbit is ~$156 billion. This figure ignores actually putting workers in orbit to construct the satellite and the weight of the transmission antenna, and the weight of the 10 Km long umbilical postulated. Let's work with it though for now. That cost of the solar panel itself is about $500/m2, so the cost of the panels themselves for the 12 km array is ~$6 billion for 12 sq km of solar cells. Ok -- so our end cost (laughingly low) for the powersat is ~162 billion. and it provides about 2GW of power. It does not include the cost of the ground-based rectennas, but we'll ignore those costs as well.<br /><br />If you used that same $162 billion to build a ground-based solar farm, you could buy <b>324 square kilometers</b> of solar cells. Solar flux at ground level is only about 1 kw/m2 so our calculation becomes<br /><br />324,000,000 m2 *

 

[bobvanx]

<font color="yellow">about the PowerTube</font><br /><br />I started a new thread for it.

 

[bobvanx]

I really appreciate your sleuthing to find some real numbers.<br /><br />I've seen the 1300 figure for earth irradiance and the 1700 for in-space; I don't have the tools to measure it, so I don't really know. It's not as important as houw many watts you get out of each kg on-orbit.<br /><br />$1000/kg <i>is</i> low, but you're missing a crucial factor (which will become apparent in a moment); your 10w/kg is likewise poorly chosen for a space-based system. Deployable solar arrays of over 100w/kg already exist, and prototypes and research demonstrators are showing that 500w/kg could be achievable. So a 1200Mw solar array (man, if I goof on the decimal, help me out) masses 12,000,000kg with today's tech, and just 2,400,000kg with tomorrow's.<br /><br />Likewise, deployable waveguides and other gosamer structures are going to be used to keep the thing light. These components will probably be made to self-assemble to as high a degree as possible. It seems reasonable to me that the solar array will be the most massive component, but let's say it's just half the weight of the whole satellite.<br /><br />So we've got 24million kg to get to orbit.<br /><br />Do you really think you're going to pay even $1000/kg to loft that? The market will come up with a way to do it for alot less.<br /><br />Suppose we want to build this in a reasonable length of time: 5 years. Heck, let's make it 2000 days. That's 12,000kg per day, every day. If you showed there was a market for that, your launch costs woud drop through the floor.<br /><br />This also shows that it's worth it to work for 5 years to develop the 500w/kg solar arrays, since then the whole thing launches with just 2400kg/day. Oh, looky there, that's the load a K1 can deliver! And that's not even the optimal delivery tool. I researched around with some cutting-edge folks, and there's a way to deliver cargo to orbit for alot less (any regular on the boards knows the real reason launch costs are inflexibly high, so this thread doesn't need t

 

[mrmorris]

<br /><font color="yellow">"Deployable solar arrays of over 100w/kg already exist, and prototypes and research demonstrators are showing that 500w/kg could be achievable."</font><br /><br />Granted. An array designed for space will be lighter. I chose one of the non-framed arrays trying to minimize weight for that reason. Use of multijunction cells wouldn't increase the weight of the panel significantly. It's currently a 133W panel at 13% efficiency, at MJ levels ~36% it'd be a 499W panel. That would make it about 50W/kg. Reducing the weight by 50% is easily within the realm of possibility if it were designed specifically for space use, so 100 W/kg seems reasonable. The future -- who knows what will happen? I'm trying to deal in current numbers wherever possible. If it's allowable to add 'what-if' speculations to this posting -- I'll make some guesses about future advances that favor ground-based alternative energy forms and throw them into the bucket. <br /><br /><br /><font color="yellow">"So a 1200Mw solar array ..."</font><br /><br />My entire post responding to Nexium was based on his 12 sq km (4 GW) array rather than an array sized specifically to produce 1200Mw, so it's a little rough trying to compare your post to mine. If you assume 36% efficient solar cells and half the weight/m2 -- then rework my equations above, you'll find the Ground-Based-Solar (GBS) *still* kicks the SPS in the teeth on a dollar/kW basis.<br /><br /><br /><font color="yellow">"So we've got 24million kg to get to orbit. <br /><br />Do you really think you're going to pay even $1000/kg to loft that? The market will come up with a way to do it for alot less. "</font><br /><br />Your original post was regarding convincing Kerry that an SPS must be built. Do I think that in the next four years we're paying a whole heck of a lot more than $1000/kg to loft it. Yep! In addition, to be reasonable -- the powersat really needs to be in GEO -- the sun-synchronous i

 

[toothferry]

I have faith that NASA, Space/Science will prosper under Kerry and just can't see science prospering much under Bush <br /><br />We need to ask ourselves, is NASA a scientific community or is it just a pork barrel money exchange subsidizing more unachievable grand goals like "Mars Missions" etc .. that will only get canned in the future, after $$Billions of investment, to the disappointment of a future generation and the future discrediting of NASA's leadership.<br /><br />Voting for Bush will shoot NASA in the foot. We need NASA to advance one unerring step at a time so that they earn back credibility in the eyes of a future generation.

 

[arobie]

And how could Kerry possibly be good for Nasa? What will he do to help them, cut their budget??

 

[yurkin]

The problem with solar power is that at present its really not economically viable. The total profits from a solar panel across the projected life of the panel does not compare to the profits that can be made from fossil fuels. Even when you factor in that you have to pay for the fuel. This is why power companies have not covered Texas with solar panels. At least not yet…<br /><br />Space based solar is even less economical since you have to factor in the launch costs. But as launch costs and panel costs drop and fuel cost don’t this is going to become more and more viable. However if fusion energy is ever figured out it might once again make solar obsolete.<br />

 

[toothferry]

NASA needs more than just money to survive in the long run. Bush could plump them up financially now with lots of cash, but if they have unpopular or unachievable goals then all that money spent will come back to haunt them later. <br /><br />Just like others, I'd like to see NASA's budget tripled rather than cut. But I think the most important issue for NASA is to make good value of every dollar they receive, whatever that might be. If they do that they should expect increasing budgets rather than diminishing budgets.<br /><br />I'm a little spooked by the initiative to go to Mars, and having that as NASA's next goal. I think its an investment in future disappointment with NASA. People are going to be complaining about how NASA is again having setbacks and cost overruns. Lots of money is going to be spent and we aren't going to get there. The fans NASA is creating because of that mission will become agitated and then want to punish NASA in the future.<br /><br />NASA needs a President that will lead them through endeavors that make the public proud. I think Bush see's the Mar's initiative as an investment in pork in the short run, but in the long run as an investment against NASA. <br /><br />It's a way to pump them up till they pop with unpopularity-- then the Government would ax NASA completely, and subsidize the next legion of Space-Military Billionaires fed from tax-dollar financing. All the while Space/Science becomes a thing of the past and the space industries become more like military industries.<br /><br />If we want NASA to remain a world leader in space, then we need Kerry to lead it.

 

[arobie]

Again, and how will Kerry do anything good for Nasa. He doesn't even care about space. Based on his voting record, he would probably cut Nasa's budget. That will not help keep Nasa a world space leader.

 

[toothferry]

If NASA's missions are well thought out, and NASA excels at them, I think the public will love NASA more, and their budget will get a lot bigger. JFKerry will do good for NASA by providing the vision and leadership.<br /><br />But if NASA's missions are simply "spend hundreds of billions to go to Mars and then where.. to an asteroid??" but we have delays, cost overruns, and finally mission failures. Well then the public will hate NASA and make it's budget shrink or even disappear, and I don't think Bush would mind that.

 

[mrmorris]

<font color="yellow">"However if fusion energy is ever figured out it might once again make solar obsolete."</font><br /><br />It's very common to point to fusion as 'the final answer' in energy production. However -- beyond the base technological problem of getting beyond 'breakeven' -- there are numerous issues before it ever becomes a viable form of energy production.<br /><br />-- Breakeven isn't enough. It has to get ***way*** beyond breakeven to be useful. Losses between the thermal energy created by the reactor and the electrical energy actually supplied to homes is better than 50%. They'll need a fusion reactor that generates a 10:1 ratio of energy output to input before it's likely to be reasonable.<br /><br />- An entire industry has to be created to 'mine' deuterium from the oceans and to create tritium for the early reactors. He3 reactors would be great, but mining the moon isn't going to happen for quite some time. Deuterium and Tritium are likely to be quite expensive on a per-Kilowatt basis. Even once fusion reactors are possible, they may not be cost-effective to run.<br /><br /><br /><br /><br />By contrast -- wind power is competitive to fossil fuels <b>today</b>. There are never any fuel costs associated with it. There is no fuel to run out. We will have wind right up until the day the sun dies (at which point no one will miss it very much).<br /><br />The only problem with wind power, in fact, is the intermittant nature of it. While this is a technological hurdle -- when compared with the hurdle of meeting (and passing) breakeven energy levels on fusion, it's a fairly minor one. I've seen two solutions for the problem which are extremely promising.<br /><br />1. Consumer-level energy storage. <br /> I read a whitepaper by a researcher working with carbon nanotubes. He wrote about the possibility of using their super-conductive properties to create high-density energy storage units. These would act as "Super UPS" that would be able t

 

[arobie]

<font color="yellow">JFKerry will do good for NASA by providing the vision and leadership.</font><br /><br />That is the part that is vague. What vision!? What leadership!?<br /><br />Kerry has shown that he has NO vision for Nasa. He would rather we stay where we are, or even retreat further.

 

[toothferry]

Kerry had said during the first debate that he was inspired by JFK, specifically the moon missions. I have faith in the choices he would make for NASA. <br /><br />from his website...<br /><hr /><br />http://www.johnkerry.com/issues/technology/ <br /><font color="yellow"> <b><br />Today, the possibilities for progress are limitless - but they won't be realized under a government that starves science and technology and slashes budgets for future research; that stifles the creativity and entrepreneurship that will produce the next big idea; that lets politics and ideology trump progress and science. <br /><br />Technological advances do not happen by accident - they happen when a society that values progress thinks big and invests in its people and their ideas. Today, we need to tap the ingenuity and innovation at the heart of our history and the core of our character. <br /><br />John Kerry and John Edwards will ensure that America leads in the great discoveries that bring greater prosperity. <br /><br /></b></font>

 

[lunatic133]

JFK who started the Vietnam War he so vehemently protested? Goody. He always seems to forget that minute detail.<br /><br />Anyway, if you're so against Mars, what do you think is going to inspire and make the public proud? Not the ISS, that's for sure, and that's the only future Kerry invisions for NASA for a LONG time.

 

[rogers_buck]

>> Not the ISS, that's for sure, and that's the only future Kerry invisions for NASA for a LONG time.<br /><br />Actually, Kerry tried to kill the ISS. That was RR's vision of someplace for the shuttle to go. The Chinese set the mission for NASA, the moon. Kerry hasn't spoken out against that mission only the financial slight of hand. We all know insufficient funds kills crews and dooms programs.<br />

 

[tjames]

It's all well and good to promise lofty goals. When Ronnie proposed the space station it was a lofty goal that went through revision after revision increasing the price. In the meantime the budget was cut and cut again so that the deadlines previously envisioned became a dream.<br /><br />The moon program had its failures, but also successes. The main failure was tossing the whole program aside as scrap with no plan for the future.<br /><br />The space shuttle is exactly the same. It had its failures but also its successes. So once again we scrap the whole program without a replacement on the board.<br /><br />Going to the moon again will be a lot more difficult and expensive run withoutnthe routine access to space the space shuttle provides (or was supposed to) This is our legacy. Never build on what you have...toss out the old<br />it's total crap. It doesn't matter if its a working system.<br /><br />Now Bush is saying let's build all new untested stuff and Kerry will cut the funds to prevent it...SOS as back in the 80's

 

[lunatic133]

But the shuttle is stagnation and if we insist on preserving it then we will never move on. I know it sucks but we've been doing the same old thing for more than 20 years and I don't see how we can build on that infastructure to create a space program that once again sparks the imagination.

 

[yurkin]

<font color="yellow"> that lets politics and ideology trump progress and science. </font><br /><br />So when Kerry wants to cancel Cassini according to his anti-nuclear ideology how is he not doing this?<br /><br />And when he doesn’t want a wind farm put up because of his “pretty view by my villa” ideology, isn’t he letting his ideology get in the way of progress.<br /><br /><br />mrmorris<br />I was only sighting fusion as a hypothetical, your right there’s no way of really knowing. The only problem I see with wind power is that although renewable it’s finite. There a limit to how much power can be extracted from the wind in the territorial US. Granted that’s probably a huge number that we are no where close too. But as energy prices drop the demand will simply increase and there will come a time when even that is not enough. This goes for all forms of renewable energy. Sometime in the future were going to have to go into space if we want to expand our power levels. Just no time soon.<br />

 

[mrmorris]

<font color="yellow">"Granted that’s probably a huge number that we are no where close too. "</font><br /><br />Three states (I believe it was North Dakota, Kansas, and Texas) have enough high-return wind energy sites to supply 100% of the US energy needs. If you were to make maximum use of *all* high-value energy sites in the US -- there's enough to supply several hundred percent of current US needs. Then add to that the other renewables already in use (hydro, goethermal, etc.) and the fact that ths southwest states have enough high-value solar sites to provide several times the US current electrical needs... we won't be running low on means of producing ground-based renewable power anytime soon.<br /><br />I've never argued that powersats are not a viable or desireable technology -- only that they're not economically justifiable <b>right now</b>. As I said earlier in the thread -- once we're at a point where they can be manufactured from extra-terrestrial materials -- they'll be extremely viable. Especially as that will mean that we'll have a significant manned presence in space to construct and maintain them.