The private company SpaceX performed a successful "drop test" of their Dragon capsule on August 12.
The Dragon capsule is what will ferry supplies and astronauts into space and to the International Space Station — and bring them back home to Earth. The drop test was done to make sure that the parachutes would deploy correctly and to measure the forces incurred on the capsule.
A helicopter lifted the capsule to 14,000 feet and dropped it over the Pacific Ocean. As you can see in the picture, all three ‘chutes deployed well. The smaller object you can see on the left with two smaller parachutes is a device that opens up drogue ‘chutes first, designed to slow and stabilize the capsule while it is still at high altitude. Once it’s stable, the larger parachutes deploy. This is similar to how other capsules historically have come back home.
There’s a pretty nifty video of all this on the SpaceX site, too. NASA has contracted with SpaceX to use their Falcon 9 rocket and Dragon capsule, so I’m pleased with the progress being made.
This is good news. The sooner private space companies can (safely) assume some of the more mundane tasks (i.e. “delivery truck” operations) from NASA the better. It will save taxpayer money and free NASA to use their shamefully small budget in ways more consistent with pure research and exploration.
Go SpaceX. I am very worried about the current politics though. The bill proposed by house is horrible for private speace. Also since when do senators have the qualification to be rocket designers?
It is also interesting how the reps stop being for a free market when they see their pork endangered.
@Elmar_M: the bill proposed is much better for human spaceflight than the administration’s proposal, which is: Kill the shuttle, fire everyone with experience, study the shuttle’s replacement until next term, then cancel it to, because we fired everyone with experience. The bill proposed is simply continuing the program of record, as planned.
Also nice is that the suborbital industry flagship operation under Virgin Galactic suffered only a slight setback when the White Knight Two failed the other day:
The huge mothership jet built to launch suborbital spaceships for Virgin Galactic suffered a collapsed landing gear Thursday morning when it landed in California’s Mojave Desert, according to officials at the Federal Aviation Administration. No injuries have been reported.
“Two FAA inspectors were on scene to examine the aircraft,” Ian Gregor, a spokesman for the FAA, told SPACE.com. “The left main landing gear was damaged. This appears at this time to be an incident and not an accident.”
[Scaled Composites are unlucky again. Remember the SS1 landing gear fail?]
Finally some information on the hot topics this week!
@ #5 Orihara:
Trolling, are we? There is no such “proposal” but a strategy with a positive scope presented, taken over with minor modifications from one developed in an independent commission where even the politicians had their say AFAIU. Why back down now, btw?
Oh, and the shuttle was “killed” under the previous administration, both in intention and in practice. AFAIU the initial part of the shuttle ET production line was disassembled and for sale, machines and locale in early ’09, which was the time the current administration took its seat. I’ve seen photos attributed to this.
Famously you can’t resurrect dead production lines, you have to redevelop a new product from scratch because the know how is gone with the specific equipment and its behavior as well as the specific personnel. The shuttle is long dead and you should know this.
@ #5 Orihara. The HLV that the bill is trying to introduce wont replace anything in any desireable way. The only thing it will replace is the pork for certain states and companies with more pork for the same states and companies. I am sure that they have been handing out plenty of “benefits” to certain people in order to keep their support, which is the only reason why they could be making such foolish decisions, that will actually HURT the job market in some of the states (e.g. Alabama, whose governor Nelson is supporting the “pork bill” ). Plus, who said that we even need a “replacement for the shuttle” anyhow?
1. Alabama’s governor is Bob Riley. Not sure who “Nelson” is.
2. I don’t much give a rip about job markets as it concerns space flight – I’d just like to see manned spaceflight continue and expand, with as much private involvement (as little gov’t) as possible.
3. Heavy lift vehicles have historically performed better and been more cost effective than the shuttle. The Saturn V, for example, had five times the payload to LEO as the shuttle (250,000# vs 50,000#), yet only cost twice as much (inflation adjusted) per launch. Having a re-usable vehicle sounds nice, but launch & especially re-entry is so hard in vehicles that it’s probably safer and more cost effective to use single components in most applications. For example, ablative heat protection is less expensive and at least as effective as shuttle tiles – and they’ve never failed catastrophically & cost anyone a crew & re-entry vehicle.
That being said I have to ask, what the F-bomb is NASA even doing these days.
Other than canceling Shuttle, extending ISS, and outreach to the Muslim community (when I heard Bolden say that I nearly crashed my car), I have not been able to figure out what exactly the new direction of NASA is? Can someone elaborate?
Judging by the reaction to Dennis Tito’s flight to space, the design of the ISS, and other space tourism proposals on what they were already doing – their goal is to keep the number of humans in space to a minimum.
I’ve seen the shuttle bay mock-up at KSC. There was more than enough room to put a module capable of carrying and supporting a dozen people for a flight. And the ISS is nothing but a Habitrail for human rats – not real *space*. Watch the videos and movies from up there – there’s almost *nowhere* more than maybe 10 feet on a side.
When I was a youngling, I had no idea why it was taking so darned long to get to space. After all, it took only a half century to go from Kitty Hawk to commercial jets.
Now, as a senior thinker, I understand: it’s just fraking physics. The velocity of the first aircraft was about 50 miles/hr. Escape velocity from earth is 2^9 times as fast, which translates to about 1,000,000 times as much energy required.
Creating that much energy in a compact, light weight engine is really, REALLY hard.
A plasma contained, nuclear thruster is one way. Anyone have a better idea?
Jamey(#11): I don’t think you *want* big, open spaces in something like the ISS, it’s just a waste of space. Plus you don’t want people getting stranded out in the middle 😉
Furthermore, the American modules were designed to be lifted up there by the shuttle, so they had to be narrow enough to fit in the cargo bay.
Gary(#12): I’m pretty sure that the first aircraft went well under 50MPH. The Wright Bros. flight at Kitty Hawk was less than 10MPH if memory serves.
I congratulate SpaceX for their success and am enthusiastic about space science and space exploration, but I think sending humans to Mars and other planets and even establishing a permanent base on the Moon should be postponed at least until we have perfected reliable and powerful plasma and ion thrusters. Not only can they cut the required travel time to more distant destinations such as Mars by at least one order of magnitude, they can potentially provide continuous acceleration most or all the way to destination and back, thus avoiding or minimizing the necessity of prolonged periods of weightlessness and its debillitating effects.
IMO a good concept for beyond Earth orbit spacecraft is the Bigelow Lunar Cruiser; basically an enhanced Sundancer or BA-330 module, docking hub, lander (if necessary) and return vehicle with whatever transfer engine happens to be usable at the time. Bigelow & Aerojet have one under design for orbital ops, but it could be swapped for most anything from a chemical Earth departure stage + service module/return stage to a nuclear or solar plasma drive later.
Gary – space elevator. All we need is a couple of spools of unobtainium & we’re in business without the gross inefficiency of reaction thrusters.
Seriously – to add to your thinking – we went from no heavier-than-air powered flight at all to both manned orbital spaceflight and the fastest air-breathing manned vehicle ever made (SR71) in just 60 years.
What’s keeping us out of space now is poor choices – poor allocation of resources. Think about this aspect of a re-usable vehicle – the shuttle is designed to bring 2000 TONS of perfectly good space-worthy hardware from orbit BACK TO EARTH every time it flies!
IMHO we should focus on putting good spaceworthy hardware UP in orbit, not bringing it back. The only things we should bring back down are people, the results of scientific experiments & samples, and the bare minimum of hardware required to reliably keep them from disintegrating into a hypersonic cloud of plasma on re-entry. 10-20 tons should be PLENTY to bring 7 people safely back from LEO.
Think of all the equipment the space shuttle brings back to earth that would have been a great addition to a space station and/or an interplanetary vehicle. And we spend all kinds of resources trying to get it all safely back on the ground – what a waste.
Gunnar – continuous acceleration to Mars is not going to help with bone & muscle loss. We use very powerful engines with high G-forces to get into orbit, but the continuous acceleration you’re talking about would be a small fraction of a g-force – barely enough to keep your drink from floating away.
IMHO the solution to this problem is staggeringly simple – make a vehicle in the shape of a bicycle tire, and spin it for 1 G at the rim for the whole trip. You could either put a drive in the hub, or not even have a hub & put multiple drives around the rim. This is more stable than the Space-Odyssey-2001 concept of a long vehicle with a small spinning section. (it was accurately depicted as eventually converting all its angular momentum into swinging end-over-end in a later movie).
I think it will be nearly impossible to convince the scientifically ignorant, the completely uninterested and the environmentally stressed (and the governments thereof) to shell out the requisite large amount of money that a manned space flight mission to another planet would cost. Unless Bill Gates wants to go to Mars I don’t think anyone will be going.
For the record I’d be delighted if it did happen, but I really don’t think it will given current human/environmental circumstances.
Sorry Torbjörn Larsson but Obama did put the final nail in the coffin for the shuttle. Bush left the final decision to end the shuttle to next president and Obama decided to go ahead and end the shuttle.
First – congrats to SpaceX for the success and best wishes for them accomplishing a lot more success soonest.
Thing is when I was a kid growing up, compulsively reading science fiction in the high school library back in the 1980’s, if someone had said in 2010 we’ll have private space companies taking supplies up to a space station I’d have shrugged and said “yeah of course, that’s expected – but what only *one* space station! Aren’t there going to be many more than that? Maybe the start of an O’Neill colony too?” Back then for 2010, I’d have expected to see people on Mars or heading there imminently and at least one if not two or three permanent Lunar bases.
When I read Stephen Baxter’s Titan novel where NASA was being mothballed – where human spaceflight was given up as not having sufficent public support under an appalling President without a clue – I thought to myself, well its well-written but its absurdly unbelievable. There’s no way the USA will ever just scrap NASA and abandon the idea of having astronauts working for the American national space program. You can’t expect me to suspend disbelief enough to think a US President would ever be dumb enough to propose that sort of betrayal of America’s greatest past accomplishements and present hopes for achieving so much more. Then along comes Obama and .. wow.
I wouldn’t have belived it but Baxter’s most depressing book got that right. American astronauts left begging for a ride with the corporations and the Russians. The USA turning its back on the expectation it’ll be a space power and still be at least participating up in the High Frontier.
This is just staggeringly pathetic and disappointing and words can’t fully express how angry and betrayed I feel by Obama’s lack of vision when it comes to human space exploration and development. Obama’s policy here is not good enough and its not okay and it is hurting the future for all of us in the West and even all of Humanity.
I know other US presidents – post JFK – have let America down badly in this area too by not doing enough to fund, support and advocate for NASA but Obama in effectively scrapping it and ending human spaceflight is far, far worse than any who have come before him – and history’s verdict on this will, I think, be utterly damning of him.
[Blockquote]1. Alabama’s governor is Bob Riley. Not sure who “Nelson” is.[/Blockquote]
Sorry, my fault, he is senator of Florida (D) and an idiot. Shelby is the guy from Alabama and he is just the same.
Thanks for the correction. Anyway, they are both equally stupid and therefore interchangeable in my mind.
[BLOCKQUOTE]I don’t much give a rip about job markets as it concerns space flight – I’d just like to see manned spaceflight continue and expand, with as much private involvement (as little gov’t) as possible.[/BLOCKQUOTE]
Agreed
[BLOCKQUOTE]Heavy lift vehicles have historically performed better and been more cost effective than the shuttle. [/BLOCKQUOTE]
Uhm, first of all, the shuttle qualifies as a heavy lift vehicle.
Second, pretty much everything is more cost effective than the shuttle.
Third, heavy lift vehicles are not as cost effective as e.g. mass manufactured medium launch vehicles or smaller one that are reusable.
This is why Arianne 6 will actually be smaller than Arianne 5. It is not as profitable.
When you launch the same vehicle hundreds of times over and over again, even if it is not reusbale, the economics of scale kick in and things become cheaper.
Space X is doing it right. They use the same engine many times and in two vehicles. This brings the cost down a lot. If they can reuse them, then things will get even cheaper.
Still, IMHO an RLV would still be best.
[Quote]I know other US presidents – post JFK – have let America down badly in this area too by not doing enough to fund, support and advocate for NASA but Obama in effectively scrapping it and ending human spaceflight is far, far worse than any who have come before him – and history’s verdict on this will, I think, be utterly damning of him.[/Quote].
@20Messier Tidy Upper.
Sorry, but this is absolutely not true!
First of all, the cancellation of the shuttle programme was set into motion by Bush.
Second, the constellation programme would have resulted in a much longer gap than aniticipated, because it was not well done and it would have been more expensive than buying flights from the russians and it would have not been very save.
Read up on this please!
Third, the commercial crew would bring US astronauts into space sooner, cheaper and safer than constellation would have.
So Obama would have actually saved the human space flight in the US.
However, if congress gets their way, it is not going to happen. They all of a sudden think that they are all qualified rocket designers while having absolutely no clue. So they will sink NASA. Obama, would have actually done something great with NASA (make space flight more affordable, so more people can fly). Congress will ruin that.
Oh, it looks like Obama is guilty for the fact that a spaceship, designed when he was a college student, had ONLY twenty years of design life, and stretched to almost the double of it. Come on! He’s only fault is being the last to get the lit match in his hand. Yes, there has been a lack of vision in the administration, but that was the former administrations, many of them: from the ones that allowed the Air Force to put its military constraints to the design, till the last ones that simply didn’t think about a replacement, mainly for NASA hatred.
Another point IMO is that the comparison with the first 60 years of aviation is not fair. At that time it was common to see pilots die. How many died before Lindbergh flight on the same path? How many died over the deserts, fighting with mach tuck and inertial coupling? Can a space program in AD 2010 accept similar risks? Of course not. We have a jungle of newspapers and adverse politicians that only wait for a similar accident to jump to the throat of NASA and the administration. On the other hand, robotics and electronics have made such big improvements that having a pilot on board is not mandatory anymore (anyone heard about UCAV?).
And finally, let us not forget the huge economical crisis and the nearing of the peak oil.
Sure, I’m really disappointed that there is nothing really new in human space flight since 1969 (like to say, five years before I was born), but I don’t blame Obama for that. Actually, I wouldn’t like to be in Obama’s shoes when it comes to space issues: because surely the rational choices would strongly fight with my dreams.
Why the big argument over whether to blame Bush or Obama? They were/are both lousy presidents who spend way to much $&@*! money on stupid stuff, leaving our economy less able to support spaceflight. They were both right to scrap the shuttle, and wrong to leave us without any replacement. I’m generally opposed to government spending, but I’d rather see it pay people to do cool stuff than to reward laziness, misbehavior or poor choices.
Messier – whenever I hear the words “lack of vision”, of course, my mind jumps to “You have paid the price for your lack of vision {crackle … aaaagh}”
Elmar_M – agreed that the SS was technically a HLV. My argument was more against trying to design a reusable launch vehicle to quickly turn around for another launch. Obviously for sub-orbital hops that’s fine, but it’s not cost-effective for orbiters.
As for Shelby … I live in AL, and am politically libertarian and personally conservative. I plan to find a good third party candidate & vote against Shelby this fall. Other than TARP, he was all too happy to participate in Bush’s spending spree.
Finally … markogts brings up a good point about safety. I disagree, though – we are now overly concerned about safety. On a similar vein – If we send people to Mars, why even bring them back? Think of it this way – imagine an offer: you have a 95% chance of becoming the first people to leave Earth orbit, an 80% chance of getting to Mars orbit alive, a 75% chance of setting foot on Mars, and <1% chance of returning to Earth (on some hypothetical future round-trip mission). I guarantee you there would be enough good, qualified people sign up for that ride that you'd have to weed out 99.9% of them.
Human explorers are so far superior to robots anyway. Think of Spirit & Opportunity. Amazing engineering feats – this is not to take away from those achievements – but a human could easily have done in a week what those rovers have take 6 years to do.
I realize that the plasma or ion drives now being designed and built would impart too small an acceleration to help significantly with preventing loss of bone and muscle mass, but part of what I mean by perfecting a plasma drive is finding a way to increase its thrust capability to something more than a tiny fraction of a g, perhaps up to 1/4 or 1/3 g. That would help significantly. Is that entirely unrealistic? If so, then the “bicycle wheel” Idea would be a good option–with or without the availability of a continuously operating plasma or ion drive. It might not be a bad idea even if a nuclear fusion plasma drive could achieve up to 1/4 or 1/3 continuous gs but no more than that.
Robert Zubrin’s idea in his book MARS DIRECT of a spacecraft with a seperable crew module and drive unit connected by a long, extendable tether so they can be rotated around each other to simulate gravity once they have achieved the correct ballistic trajectory for Mars is also an intriguing and possibly workable idea, if we have to preclude accelerating all the way to Mars.
If we could build a spacecraft with a plasma or ion drive that was capable of accelerating it all the way to Mars even at a small fraction of a g-force, the tremendous shortening of the trip duration would itself go a long way towards reducing loss of bone and muscle mass–not to mention the tremendous reduction in the amount of consumables such as water, food and air that would have to be taken along.
Blaming Obama for the current mess is more than a little unfair. Every Prsident from Reagan onwards has made grand promises about Moon/Mars missions, and never funded them. There have been a number of prgorams to maodify or replace the STS like the X-33, NASP, and Shuttle-C(which ironically was essentially an SD HLV), and they’ve all been abandoned, usually after major time and cost overruns.
Now Obama enters the Oval office with a trashed economy, a geriatric STS, and the supposed quick simple, and cheap solution to maintiaining MSF that was Ares I already prvoving to be none of the above. There are no good options for the US manned space program right now but Obama’s focus on R&D and commercial space was probably less bad than spending a fortune on an HLV with no mission hardware.
Also it might be instructive to look at what the aerospace compaines are willing to spend their money on. Lockheed Martin are still working on RLV’s, and Boeing is working on the CST-100 capsule, and then you have new space companies like SpaceX. None of them seem intertested in doing any HLV development unless they get a nice cost plus contract from Congress.
@ChH [Quote]My argument was more against trying to design a reusable launch vehicle to quickly turn around for another launch. Obviously for sub-orbital hops that’s fine, but it’s not cost-effective for orbiters[/Quote]
Sorry, but I can not agree with this either.
RLVs are the most important next step. You rather sacrifice payload and fly more often than fly less often and have more payload. Again the economics of scale kick in, if you fly more often, plus it becomes more routine.
The shuttle was a failure in every aspect, because it was designed to do to many things at once. The same was true for the X33, which once again made the point that NASA can not design launch vehicles, because idiots from all parts of the government will interfere with their “great ideas” to make sure that they get what their resort needs, or their lobbyists want.
The X33, once again tried to be a heavy lifter, a crew transport, a space station, an orbital repair platform, a large cross range glider, testbed for new technology and an RLV at once. It simply had to fail.
Now congress thinks that they are qualified to design a HLV. Why, only god knows… no, I bet he does not either.
In my experience, no matter what party politicians belong to, be it reps, dems, libertarian reps, etc, they all will happily take their pork if they can.
Ironically Shelbys decision will actually COST jobs in Al, if he gets his way. But he is to dense to realize that, or probably does realize it, but is to dense to care.
On Zubrins high flying Mars plans. Lets get into LEO first and I mean for a reasonable cost. So far there is no way to do that and from what I can see, wont be for a long time. SpaceX is on the right track, but they too are still far away from this goal.
NASAs job should be to research the technologies that will enable private companies to build cheaper and better even reusable LVs, that NASA can then in turn hire rides on from them. Everybody wins (other than the porkers in congress).
On your idea for a one way trip to Mars: It is is a horrible idea to even think something like that. The US has never lost an astronaut in space and I think this is good that way. Sending someone on a one way trip is despicable. Would you like to see your son go on such a mission?
IMHO the solution to this problem is staggeringly simple – make a vehicle in the shape of a bicycle tire, and spin it for 1 G at the rim for the whole trip.
Erm … surely it’d be more stable to have two sections that rotate in opposite directions? Wouldn’t the gyroscopic effect keep sending you off course otherwise?
Elmar, on Mars – let me clarify – I’m talking about a mission designed to put volunteers on Mars and keep them alive & in communication with Earth there until they die of natural causes or accident (as opposed to starvation or suffocation – I agree that would be unacceptable). Presumably many of these volunteers would be older anyway – like in their 50s or perhaps 60s. So – I’d probably be dead before my son would do something like that. And if he’s had a good life, raised a family, gained engineering & science expertise that would be useful on such a mission, and he has a chance to be among the first humans to set foot on another planet, and HE WANTS TO DO IT, yes – I would be proud to see him do that. FWIW I have one son who is currently 5 years old.
Nigel, if you spin a long body around an axis made of the line of its travel (like a long bullet spinning when it leaves a muzzle), yes – the gyroscopic effect will cause the object eventually to tumble around the axis with the greatest angular momentum (end-over-end for a long body). But with a bicycle tire-shaped vessel you’d spin it around the axis with the greatest angular momentum to beging with, so it is stable.
Now – with current drive technology, your spin angle relative to the sun would swung 180° around by the time you get to Mars 6-9 months later, having orbited half way around the sun. But with Gunnar’s 1/4 g drive running the whole way, the trip would take only take 4 or 5 days, and you’d be traveling on almost a straight line, and would end up at close to the same angle relative to the sun when you arrive at Mars as you were when you left Earth.
Sean (#13) wrote: ” I don’t think you *want* big, open spaces in something like the ISS, it’s just a waste of space. Plus you don’t want people getting stranded out in the middle.”
Actually, big open spaces will follow naturally from the design requirements of future space stations. I mean the “wheel” designs from science fiction, or from von Braun’s concepts.
The basic idea is that the station must rotate to provide artificial gravity for long-term habitation. Then, to avoid nausea due to rapid rotation, a large diameter is required. Mechanical factors probably mean the living-quarters torus at the rim will have a relatively large diameter compared to ISS. Large pressurized spaces are also useful for things like spacecraft assembly and maintenance (probably at the hub of the station.)
None of this is going to happen soon. But when we achieve routine use of Earth orbit, it will.
Space elevators are a cool idea, unfortunately, like all cool ideas, there are practical obstacles.
1) the elevator passes thru the debris field around earth. Potentially catastrophic impacts may impede development.
2) Elevator passes thru the Van Allen Radiation belts.
3) the ride takes two weeks to get to geosync orbit.
Many more problems to solve beyond the growing of carbon fiber many meters in length but that’s the FIRST thing we have to solve.
High thrust plasma/ion engines are quite possible. Just have to scale up the engineering(vasimir is already at 200 kw. A 200 Mwatt thruster is just bigger engines.)
The major inhibiter is energy. Which implies either the availability of fusion or fission power.
The nuclear light bulb is one way to efficiently use thermal nuclear energy for thrust. It too has some development issues, beyond the public perception that all fission energy is bad.
The US air force is currently working with the Brazillian air force in developing Leik Myrobos Light craft. Another great idea with a long lead time to development.
Physicist Mike Combs proposed hot air balloon platforms to support a mass driver to accelerate craft to orbital velocity. They would operate from ground level to 120,000 feet. Another great idea but,,,it would have an upfront cost of 50 to 60 billion dollars. Hard to convince investors to provide for that.
I currently lean toward a variation on the nuc light bulb as a personnel transport to orbit but I expect it would have a hard time passing the public opinion resistance in the USA. Expect if such is ever built, it will be done by a nuclear state that doesn’t have to bow to the prejudices of its populace.
I am with Gary here, nuclear lightbulb makes the most sense at the moment.
There is also a new development using Tungsten based fuel rods that allow for higher reactor core temperatures without the need for a gas core reactor.
The nuclear lightbulb concept is completely new to me, and sounds exciting. As soon as I finish entering this post, I am going to google it and see what I can find out about it. If any of you can suggest some good sources describing it, I would greatly appreciate it!
There was a nice article on nuclearspace once that described it pretty well. Unfortunately it is gone now.
Basically it is a gas core reactor in a shell of fused silica.
Gas Core reactors can run much hotter than solid core reactors. This results in a higher exhaust velocity for the reaction mass “rocket” fuel (usually liquid hydrogen).
The problem with this type of reactor is that you exhaust radio active reactor fuel together with the rocket exhaust (since it is a gas and not a solid rod, you can not separate the two).
Now, the lightbulb design basically allows to have both and you only loose a little of the temperature in the process.
The new tungsten based design that I mentioned is probably the next best to a lightbulb, but requires less work to get going.
It can run much hotter than previous solid rod designs. They are not reaching gas core reactor levels yet, but they could get there if more research was done.
Steve Howe – Director, Center for Space Nuclear Research presented it at the recent New Space 2010 conference. Here is a video for those that have not seen it: http://www.youtube.com/watch?v=dV75c8tTFdk
Howe is the 3rd presenter (IMHO it would have been good to split this up into multiple videos, one for each presenter, as this is quite long).
As you think about the design, you’ll probably notice one, tiny little problem; “most of the energy” generated is in the UV range.
When generating a giga watt of energy, the term “most” leaves a lot of residual energy to heat the envelop, which would have to be carried away. I’m thinking specifically of conduction heating from the uranium hexafloride to the containment walls and high speed neutrons.
It occurred to me early on, the simplest way to negate the conduction heating problem is to further confine the fuel core with magnetic fields. These would also allow magnetic compression of the core, for precise control of the fission rate and emergency scrubbing, should a failure arise. I expect “burning” the reactant would also be more complete, since we’re running it at 25,000 Kelvins, with lots of neutron radiation to degrade the isotopes formed during Uranium fissioning. More “oomph” for the kilograms consumed.
In a typical, solid core nuc plant we get, from Wiki, “The fuel rods will spend about 3 operational cycles (typically 6 years total now) inside the reactor, generally until about 3% of their uranium has been fissioned, then they will be moved to a spent fuel pool where the short lived isotopes generated by fission can decay away. ”
Gas core reactors “burn” more of the uranium than solid core reactors. I expect this thruster would “burn” a lot more efficiently than standard gas core reactors.
It may well be an idea that has come of age(in the sense of “when it’s time to steamboat, you steamboat”).
Thanks Gary! I already found that link in my google search, though. I found it quite interesting. I can’t help but wonder, though, why bother to continue to put so much emphasis on developing heavy lift vehicles using ordinary chemical rockets when this concept shows such promise. I suppose part of it is anti-nuclear fission prejudice. I wonder too how hard it would be to shut it down upon reaching the desired destination or to start it back up again when desiring to return.
MENU
A Dragon drop test.
*groan*
This is good news. The sooner private space companies can (safely) assume some of the more mundane tasks (i.e. “delivery truck” operations) from NASA the better. It will save taxpayer money and free NASA to use their shamefully small budget in ways more consistent with pure research and exploration.
Go SpaceX. I am very worried about the current politics though. The bill proposed by house is horrible for private speace. Also since when do senators have the qualification to be rocket designers?
It is also interesting how the reps stop being for a free market when they see their pork endangered.
Cool pics on the site. I like the one where you can see Morro Rock in the background.
@Elmar_M: the bill proposed is much better for human spaceflight than the administration’s proposal, which is: Kill the shuttle, fire everyone with experience, study the shuttle’s replacement until next term, then cancel it to, because we fired everyone with experience. The bill proposed is simply continuing the program of record, as planned.
Ooh, nice!
Also nice is that the suborbital industry flagship operation under Virgin Galactic suffered only a slight setback when the White Knight Two failed the other day:
[Scaled Composites are unlucky again. Remember the SS1 landing gear fail?]
Finally some information on the hot topics this week!
@ #5 Orihara:
Trolling, are we? There is no such “proposal” but a strategy with a positive scope presented, taken over with minor modifications from one developed in an independent commission where even the politicians had their say AFAIU. Why back down now, btw?
Oh, and the shuttle was “killed” under the previous administration, both in intention and in practice. AFAIU the initial part of the shuttle ET production line was disassembled and for sale, machines and locale in early ’09, which was the time the current administration took its seat. I’ve seen photos attributed to this.
Famously you can’t resurrect dead production lines, you have to redevelop a new product from scratch because the know how is gone with the specific equipment and its behavior as well as the specific personnel. The shuttle is long dead and you should know this.
@6. Torbjorn Larsson … Beautiful job putting down @5 Orihara. Well done.
@ #5 Orihara. The HLV that the bill is trying to introduce wont replace anything in any desireable way. The only thing it will replace is the pork for certain states and companies with more pork for the same states and companies. I am sure that they have been handing out plenty of “benefits” to certain people in order to keep their support, which is the only reason why they could be making such foolish decisions, that will actually HURT the job market in some of the states (e.g. Alabama, whose governor Nelson is supporting the “pork bill” ). Plus, who said that we even need a “replacement for the shuttle” anyhow?
1. Alabama’s governor is Bob Riley. Not sure who “Nelson” is.
2. I don’t much give a rip about job markets as it concerns space flight – I’d just like to see manned spaceflight continue and expand, with as much private involvement (as little gov’t) as possible.
3. Heavy lift vehicles have historically performed better and been more cost effective than the shuttle. The Saturn V, for example, had five times the payload to LEO as the shuttle (250,000# vs 50,000#), yet only cost twice as much (inflation adjusted) per launch. Having a re-usable vehicle sounds nice, but launch & especially re-entry is so hard in vehicles that it’s probably safer and more cost effective to use single components in most applications. For example, ablative heat protection is less expensive and at least as effective as shuttle tiles – and they’ve never failed catastrophically & cost anyone a crew & re-entry vehicle.
Private Space is wonderful
Constellation was a slow to develop and expensive
That being said I have to ask, what the F-bomb is NASA even doing these days.
Other than canceling Shuttle, extending ISS, and outreach to the Muslim community (when I heard Bolden say that I nearly crashed my car), I have not been able to figure out what exactly the new direction of NASA is? Can someone elaborate?
Judging by the reaction to Dennis Tito’s flight to space, the design of the ISS, and other space tourism proposals on what they were already doing – their goal is to keep the number of humans in space to a minimum.
I’ve seen the shuttle bay mock-up at KSC. There was more than enough room to put a module capable of carrying and supporting a dozen people for a flight. And the ISS is nothing but a Habitrail for human rats – not real *space*. Watch the videos and movies from up there – there’s almost *nowhere* more than maybe 10 feet on a side.
When I was a youngling, I had no idea why it was taking so darned long to get to space. After all, it took only a half century to go from Kitty Hawk to commercial jets.
Now, as a senior thinker, I understand: it’s just fraking physics. The velocity of the first aircraft was about 50 miles/hr. Escape velocity from earth is 2^9 times as fast, which translates to about 1,000,000 times as much energy required.
Creating that much energy in a compact, light weight engine is really, REALLY hard.
A plasma contained, nuclear thruster is one way. Anyone have a better idea?
Gary 7
Jamey(#11): I don’t think you *want* big, open spaces in something like the ISS, it’s just a waste of space. Plus you don’t want people getting stranded out in the middle 😉
Furthermore, the American modules were designed to be lifted up there by the shuttle, so they had to be narrow enough to fit in the cargo bay.
Gary(#12): I’m pretty sure that the first aircraft went well under 50MPH. The Wright Bros. flight at Kitty Hawk was less than 10MPH if memory serves.
I congratulate SpaceX for their success and am enthusiastic about space science and space exploration, but I think sending humans to Mars and other planets and even establishing a permanent base on the Moon should be postponed at least until we have perfected reliable and powerful plasma and ion thrusters. Not only can they cut the required travel time to more distant destinations such as Mars by at least one order of magnitude, they can potentially provide continuous acceleration most or all the way to destination and back, thus avoiding or minimizing the necessity of prolonged periods of weightlessness and its debillitating effects.
IMO a good concept for beyond Earth orbit spacecraft is the Bigelow Lunar Cruiser; basically an enhanced Sundancer or BA-330 module, docking hub, lander (if necessary) and return vehicle with whatever transfer engine happens to be usable at the time. Bigelow & Aerojet have one under design for orbital ops, but it could be swapped for most anything from a chemical Earth departure stage + service module/return stage to a nuclear or solar plasma drive later.
Gary – space elevator. All we need is a couple of spools of unobtainium & we’re in business without the gross inefficiency of reaction thrusters.
Seriously – to add to your thinking – we went from no heavier-than-air powered flight at all to both manned orbital spaceflight and the fastest air-breathing manned vehicle ever made (SR71) in just 60 years.
What’s keeping us out of space now is poor choices – poor allocation of resources. Think about this aspect of a re-usable vehicle – the shuttle is designed to bring 2000 TONS of perfectly good space-worthy hardware from orbit BACK TO EARTH every time it flies!
IMHO we should focus on putting good spaceworthy hardware UP in orbit, not bringing it back. The only things we should bring back down are people, the results of scientific experiments & samples, and the bare minimum of hardware required to reliably keep them from disintegrating into a hypersonic cloud of plasma on re-entry. 10-20 tons should be PLENTY to bring 7 people safely back from LEO.
Think of all the equipment the space shuttle brings back to earth that would have been a great addition to a space station and/or an interplanetary vehicle. And we spend all kinds of resources trying to get it all safely back on the ground – what a waste.
Gunnar – continuous acceleration to Mars is not going to help with bone & muscle loss. We use very powerful engines with high G-forces to get into orbit, but the continuous acceleration you’re talking about would be a small fraction of a g-force – barely enough to keep your drink from floating away.
IMHO the solution to this problem is staggeringly simple – make a vehicle in the shape of a bicycle tire, and spin it for 1 G at the rim for the whole trip. You could either put a drive in the hub, or not even have a hub & put multiple drives around the rim. This is more stable than the Space-Odyssey-2001 concept of a long vehicle with a small spinning section. (it was accurately depicted as eventually converting all its angular momentum into swinging end-over-end in a later movie).
I think it will be nearly impossible to convince the scientifically ignorant, the completely uninterested and the environmentally stressed (and the governments thereof) to shell out the requisite large amount of money that a manned space flight mission to another planet would cost. Unless Bill Gates wants to go to Mars I don’t think anyone will be going.
For the record I’d be delighted if it did happen, but I really don’t think it will given current human/environmental circumstances.
Sorry Torbjörn Larsson but Obama did put the final nail in the coffin for the shuttle. Bush left the final decision to end the shuttle to next president and Obama decided to go ahead and end the shuttle.
First – congrats to SpaceX for the success and best wishes for them accomplishing a lot more success soonest.
Thing is when I was a kid growing up, compulsively reading science fiction in the high school library back in the 1980’s, if someone had said in 2010 we’ll have private space companies taking supplies up to a space station I’d have shrugged and said “yeah of course, that’s expected – but what only *one* space station! Aren’t there going to be many more than that? Maybe the start of an O’Neill colony too?” Back then for 2010, I’d have expected to see people on Mars or heading there imminently and at least one if not two or three permanent Lunar bases.
When I read Stephen Baxter’s Titan novel where NASA was being mothballed – where human spaceflight was given up as not having sufficent public support under an appalling President without a clue – I thought to myself, well its well-written but its absurdly unbelievable. There’s no way the USA will ever just scrap NASA and abandon the idea of having astronauts working for the American national space program. You can’t expect me to suspend disbelief enough to think a US President would ever be dumb enough to propose that sort of betrayal of America’s greatest past accomplishements and present hopes for achieving so much more. Then along comes Obama and .. wow.
I wouldn’t have belived it but Baxter’s most depressing book got that right. American astronauts left begging for a ride with the corporations and the Russians. The USA turning its back on the expectation it’ll be a space power and still be at least participating up in the High Frontier.
This is just staggeringly pathetic and disappointing and words can’t fully express how angry and betrayed I feel by Obama’s lack of vision when it comes to human space exploration and development. Obama’s policy here is not good enough and its not okay and it is hurting the future for all of us in the West and even all of Humanity.
I know other US presidents – post JFK – have let America down badly in this area too by not doing enough to fund, support and advocate for NASA but Obama in effectively scrapping it and ending human spaceflight is far, far worse than any who have come before him – and history’s verdict on this will, I think, be utterly damning of him.
[Blockquote]1. Alabama’s governor is Bob Riley. Not sure who “Nelson” is.[/Blockquote]
Sorry, my fault, he is senator of Florida (D) and an idiot. Shelby is the guy from Alabama and he is just the same.
Thanks for the correction. Anyway, they are both equally stupid and therefore interchangeable in my mind.
[BLOCKQUOTE]I don’t much give a rip about job markets as it concerns space flight – I’d just like to see manned spaceflight continue and expand, with as much private involvement (as little gov’t) as possible.[/BLOCKQUOTE]
Agreed
[BLOCKQUOTE]Heavy lift vehicles have historically performed better and been more cost effective than the shuttle. [/BLOCKQUOTE]
Uhm, first of all, the shuttle qualifies as a heavy lift vehicle.
Second, pretty much everything is more cost effective than the shuttle.
Third, heavy lift vehicles are not as cost effective as e.g. mass manufactured medium launch vehicles or smaller one that are reusable.
This is why Arianne 6 will actually be smaller than Arianne 5. It is not as profitable.
When you launch the same vehicle hundreds of times over and over again, even if it is not reusbale, the economics of scale kick in and things become cheaper.
Space X is doing it right. They use the same engine many times and in two vehicles. This brings the cost down a lot. If they can reuse them, then things will get even cheaper.
Still, IMHO an RLV would still be best.
[Quote]I know other US presidents – post JFK – have let America down badly in this area too by not doing enough to fund, support and advocate for NASA but Obama in effectively scrapping it and ending human spaceflight is far, far worse than any who have come before him – and history’s verdict on this will, I think, be utterly damning of him.[/Quote].
@20Messier Tidy Upper.
Sorry, but this is absolutely not true!
First of all, the cancellation of the shuttle programme was set into motion by Bush.
Second, the constellation programme would have resulted in a much longer gap than aniticipated, because it was not well done and it would have been more expensive than buying flights from the russians and it would have not been very save.
Read up on this please!
Third, the commercial crew would bring US astronauts into space sooner, cheaper and safer than constellation would have.
So Obama would have actually saved the human space flight in the US.
However, if congress gets their way, it is not going to happen. They all of a sudden think that they are all qualified rocket designers while having absolutely no clue. So they will sink NASA. Obama, would have actually done something great with NASA (make space flight more affordable, so more people can fly). Congress will ruin that.
Oh, it looks like Obama is guilty for the fact that a spaceship, designed when he was a college student, had ONLY twenty years of design life, and stretched to almost the double of it. Come on! He’s only fault is being the last to get the lit match in his hand. Yes, there has been a lack of vision in the administration, but that was the former administrations, many of them: from the ones that allowed the Air Force to put its military constraints to the design, till the last ones that simply didn’t think about a replacement, mainly for NASA hatred.
Another point IMO is that the comparison with the first 60 years of aviation is not fair. At that time it was common to see pilots die. How many died before Lindbergh flight on the same path? How many died over the deserts, fighting with mach tuck and inertial coupling? Can a space program in AD 2010 accept similar risks? Of course not. We have a jungle of newspapers and adverse politicians that only wait for a similar accident to jump to the throat of NASA and the administration. On the other hand, robotics and electronics have made such big improvements that having a pilot on board is not mandatory anymore (anyone heard about UCAV?).
And finally, let us not forget the huge economical crisis and the nearing of the peak oil.
Sure, I’m really disappointed that there is nothing really new in human space flight since 1969 (like to say, five years before I was born), but I don’t blame Obama for that. Actually, I wouldn’t like to be in Obama’s shoes when it comes to space issues: because surely the rational choices would strongly fight with my dreams.
Why the big argument over whether to blame Bush or Obama? They were/are both lousy presidents who spend way to much $&@*! money on stupid stuff, leaving our economy less able to support spaceflight. They were both right to scrap the shuttle, and wrong to leave us without any replacement. I’m generally opposed to government spending, but I’d rather see it pay people to do cool stuff than to reward laziness, misbehavior or poor choices.
Messier – whenever I hear the words “lack of vision”, of course, my mind jumps to “You have paid the price for your lack of vision {crackle … aaaagh}”
Elmar_M – agreed that the SS was technically a HLV. My argument was more against trying to design a reusable launch vehicle to quickly turn around for another launch. Obviously for sub-orbital hops that’s fine, but it’s not cost-effective for orbiters.
As for Shelby … I live in AL, and am politically libertarian and personally conservative. I plan to find a good third party candidate & vote against Shelby this fall. Other than TARP, he was all too happy to participate in Bush’s spending spree.
Finally … markogts brings up a good point about safety. I disagree, though – we are now overly concerned about safety. On a similar vein – If we send people to Mars, why even bring them back? Think of it this way – imagine an offer: you have a 95% chance of becoming the first people to leave Earth orbit, an 80% chance of getting to Mars orbit alive, a 75% chance of setting foot on Mars, and <1% chance of returning to Earth (on some hypothetical future round-trip mission). I guarantee you there would be enough good, qualified people sign up for that ride that you'd have to weed out 99.9% of them.
Human explorers are so far superior to robots anyway. Think of Spirit & Opportunity. Amazing engineering feats – this is not to take away from those achievements – but a human could easily have done in a week what those rovers have take 6 years to do.
ChH
I realize that the plasma or ion drives now being designed and built would impart too small an acceleration to help significantly with preventing loss of bone and muscle mass, but part of what I mean by perfecting a plasma drive is finding a way to increase its thrust capability to something more than a tiny fraction of a g, perhaps up to 1/4 or 1/3 g. That would help significantly. Is that entirely unrealistic? If so, then the “bicycle wheel” Idea would be a good option–with or without the availability of a continuously operating plasma or ion drive. It might not be a bad idea even if a nuclear fusion plasma drive could achieve up to 1/4 or 1/3 continuous gs but no more than that.
Robert Zubrin’s idea in his book MARS DIRECT of a spacecraft with a seperable crew module and drive unit connected by a long, extendable tether so they can be rotated around each other to simulate gravity once they have achieved the correct ballistic trajectory for Mars is also an intriguing and possibly workable idea, if we have to preclude accelerating all the way to Mars.
If we could build a spacecraft with a plasma or ion drive that was capable of accelerating it all the way to Mars even at a small fraction of a g-force, the tremendous shortening of the trip duration would itself go a long way towards reducing loss of bone and muscle mass–not to mention the tremendous reduction in the amount of consumables such as water, food and air that would have to be taken along.
Blaming Obama for the current mess is more than a little unfair. Every Prsident from Reagan onwards has made grand promises about Moon/Mars missions, and never funded them. There have been a number of prgorams to maodify or replace the STS like the X-33, NASP, and Shuttle-C(which ironically was essentially an SD HLV), and they’ve all been abandoned, usually after major time and cost overruns.
Now Obama enters the Oval office with a trashed economy, a geriatric STS, and the supposed quick simple, and cheap solution to maintiaining MSF that was Ares I already prvoving to be none of the above. There are no good options for the US manned space program right now but Obama’s focus on R&D and commercial space was probably less bad than spending a fortune on an HLV with no mission hardware.
Also it might be instructive to look at what the aerospace compaines are willing to spend their money on. Lockheed Martin are still working on RLV’s, and Boeing is working on the CST-100 capsule, and then you have new space companies like SpaceX. None of them seem intertested in doing any HLV development unless they get a nice cost plus contract from Congress.
@ChH [Quote]My argument was more against trying to design a reusable launch vehicle to quickly turn around for another launch. Obviously for sub-orbital hops that’s fine, but it’s not cost-effective for orbiters[/Quote]
Sorry, but I can not agree with this either.
RLVs are the most important next step. You rather sacrifice payload and fly more often than fly less often and have more payload. Again the economics of scale kick in, if you fly more often, plus it becomes more routine.
The shuttle was a failure in every aspect, because it was designed to do to many things at once. The same was true for the X33, which once again made the point that NASA can not design launch vehicles, because idiots from all parts of the government will interfere with their “great ideas” to make sure that they get what their resort needs, or their lobbyists want.
The X33, once again tried to be a heavy lifter, a crew transport, a space station, an orbital repair platform, a large cross range glider, testbed for new technology and an RLV at once. It simply had to fail.
Now congress thinks that they are qualified to design a HLV. Why, only god knows… no, I bet he does not either.
In my experience, no matter what party politicians belong to, be it reps, dems, libertarian reps, etc, they all will happily take their pork if they can.
Ironically Shelbys decision will actually COST jobs in Al, if he gets his way. But he is to dense to realize that, or probably does realize it, but is to dense to care.
On Zubrins high flying Mars plans. Lets get into LEO first and I mean for a reasonable cost. So far there is no way to do that and from what I can see, wont be for a long time. SpaceX is on the right track, but they too are still far away from this goal.
NASAs job should be to research the technologies that will enable private companies to build cheaper and better even reusable LVs, that NASA can then in turn hire rides on from them. Everybody wins (other than the porkers in congress).
On your idea for a one way trip to Mars: It is is a horrible idea to even think something like that. The US has never lost an astronaut in space and I think this is good that way. Sending someone on a one way trip is despicable. Would you like to see your son go on such a mission?
ChH (17) said:
Erm … surely it’d be more stable to have two sections that rotate in opposite directions? Wouldn’t the gyroscopic effect keep sending you off course otherwise?
Elmar, on Mars – let me clarify – I’m talking about a mission designed to put volunteers on Mars and keep them alive & in communication with Earth there until they die of natural causes or accident (as opposed to starvation or suffocation – I agree that would be unacceptable). Presumably many of these volunteers would be older anyway – like in their 50s or perhaps 60s. So – I’d probably be dead before my son would do something like that. And if he’s had a good life, raised a family, gained engineering & science expertise that would be useful on such a mission, and he has a chance to be among the first humans to set foot on another planet, and HE WANTS TO DO IT, yes – I would be proud to see him do that. FWIW I have one son who is currently 5 years old.
Nigel, if you spin a long body around an axis made of the line of its travel (like a long bullet spinning when it leaves a muzzle), yes – the gyroscopic effect will cause the object eventually to tumble around the axis with the greatest angular momentum (end-over-end for a long body). But with a bicycle tire-shaped vessel you’d spin it around the axis with the greatest angular momentum to beging with, so it is stable.
Now – with current drive technology, your spin angle relative to the sun would swung 180° around by the time you get to Mars 6-9 months later, having orbited half way around the sun. But with Gunnar’s 1/4 g drive running the whole way, the trip would take only take 4 or 5 days, and you’d be traveling on almost a straight line, and would end up at close to the same angle relative to the sun when you arrive at Mars as you were when you left Earth.
Sean (#13) wrote: ” I don’t think you *want* big, open spaces in something like the ISS, it’s just a waste of space. Plus you don’t want people getting stranded out in the middle.”
Actually, big open spaces will follow naturally from the design requirements of future space stations. I mean the “wheel” designs from science fiction, or from von Braun’s concepts.
The basic idea is that the station must rotate to provide artificial gravity for long-term habitation. Then, to avoid nausea due to rapid rotation, a large diameter is required. Mechanical factors probably mean the living-quarters torus at the rim will have a relatively large diameter compared to ISS. Large pressurized spaces are also useful for things like spacecraft assembly and maintenance (probably at the hub of the station.)
None of this is going to happen soon. But when we achieve routine use of Earth orbit, it will.
16. ChH
Space elevators are a cool idea, unfortunately, like all cool ideas, there are practical obstacles.
1) the elevator passes thru the debris field around earth. Potentially catastrophic impacts may impede development.
2) Elevator passes thru the Van Allen Radiation belts.
3) the ride takes two weeks to get to geosync orbit.
Many more problems to solve beyond the growing of carbon fiber many meters in length but that’s the FIRST thing we have to solve.
High thrust plasma/ion engines are quite possible. Just have to scale up the engineering(vasimir is already at 200 kw. A 200 Mwatt thruster is just bigger engines.)
The major inhibiter is energy. Which implies either the availability of fusion or fission power.
The nuclear light bulb is one way to efficiently use thermal nuclear energy for thrust. It too has some development issues, beyond the public perception that all fission energy is bad.
The US air force is currently working with the Brazillian air force in developing Leik Myrobos Light craft. Another great idea with a long lead time to development.
Physicist Mike Combs proposed hot air balloon platforms to support a mass driver to accelerate craft to orbital velocity. They would operate from ground level to 120,000 feet. Another great idea but,,,it would have an upfront cost of 50 to 60 billion dollars. Hard to convince investors to provide for that.
I currently lean toward a variation on the nuc light bulb as a personnel transport to orbit but I expect it would have a hard time passing the public opinion resistance in the USA. Expect if such is ever built, it will be done by a nuclear state that doesn’t have to bow to the prejudices of its populace.
Mandarin, anyone?
Gary 7
I am with Gary here, nuclear lightbulb makes the most sense at the moment.
There is also a new development using Tungsten based fuel rods that allow for higher reactor core temperatures without the need for a gas core reactor.
The nuclear lightbulb concept is completely new to me, and sounds exciting. As soon as I finish entering this post, I am going to google it and see what I can find out about it. If any of you can suggest some good sources describing it, I would greatly appreciate it!
There was a nice article on nuclearspace once that described it pretty well. Unfortunately it is gone now.
Basically it is a gas core reactor in a shell of fused silica.
Gas Core reactors can run much hotter than solid core reactors. This results in a higher exhaust velocity for the reaction mass “rocket” fuel (usually liquid hydrogen).
The problem with this type of reactor is that you exhaust radio active reactor fuel together with the rocket exhaust (since it is a gas and not a solid rod, you can not separate the two).
Now, the lightbulb design basically allows to have both and you only loose a little of the temperature in the process.
The new tungsten based design that I mentioned is probably the next best to a lightbulb, but requires less work to get going.
It can run much hotter than previous solid rod designs. They are not reaching gas core reactor levels yet, but they could get there if more research was done.
Steve Howe – Director, Center for Space Nuclear Research presented it at the recent New Space 2010 conference. Here is a video for those that have not seen it:
http://www.youtube.com/watch?v=dV75c8tTFdk
Howe is the 3rd presenter (IMHO it would have been good to split this up into multiple videos, one for each presenter, as this is quite long).
Howe is about 32 minutes into the video.
33. Gunnar
Here’s a link that gives a fair amount of info for the Nuc Light Bulb.
http://www.nuclearspace.com/Liberty_ship_pg10.aspx
As you think about the design, you’ll probably notice one, tiny little problem; “most of the energy” generated is in the UV range.
When generating a giga watt of energy, the term “most” leaves a lot of residual energy to heat the envelop, which would have to be carried away. I’m thinking specifically of conduction heating from the uranium hexafloride to the containment walls and high speed neutrons.
It occurred to me early on, the simplest way to negate the conduction heating problem is to further confine the fuel core with magnetic fields. These would also allow magnetic compression of the core, for precise control of the fission rate and emergency scrubbing, should a failure arise. I expect “burning” the reactant would also be more complete, since we’re running it at 25,000 Kelvins, with lots of neutron radiation to degrade the isotopes formed during Uranium fissioning. More “oomph” for the kilograms consumed.
In a typical, solid core nuc plant we get, from Wiki, “The fuel rods will spend about 3 operational cycles (typically 6 years total now) inside the reactor, generally until about 3% of their uranium has been fissioned, then they will be moved to a spent fuel pool where the short lived isotopes generated by fission can decay away. ”
Gas core reactors “burn” more of the uranium than solid core reactors. I expect this thruster would “burn” a lot more efficiently than standard gas core reactors.
It may well be an idea that has come of age(in the sense of “when it’s time to steamboat, you steamboat”).
Gary 7
Thanks Gary! That is the link I have been looking for, for a while.
It was down when they renewed the page. I guess they put it back up again.
36. Gary
Thanks Gary! I already found that link in my google search, though. I found it quite interesting. I can’t help but wonder, though, why bother to continue to put so much emphasis on developing heavy lift vehicles using ordinary chemical rockets when this concept shows such promise. I suppose part of it is anti-nuclear fission prejudice. I wonder too how hard it would be to shut it down upon reaching the desired destination or to start it back up again when desiring to return.