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Human rated reactors in the megawatts? Hardly, the ISS with its acre or two of solar arrays will produce a mere 200kWe, it doesn't take that much power to run a human outpost... Zubrin's MarsDirect is built around a reactor that makes around 50-150kWe, and thats for running a small fuel factory too. A large nuclear reactor powerd death ray would require many of these strung together, an unreasonable design.
And the fact remains that you don't need a nuclear reactor to build a megalaser cannon... oxygen/iodine lasers are lighter, more powerful, and easier to make than a big electric one. Oxygen and iodine are also, I think, storable enough, the question is if the lasers' componets are. A chemical laser is better suited because it can produce all the energy needed only when its needed, whereas a reactor will be sitting idle 99.99% of the time. A reactor that recharges a power storage device would also limit fire rate, whereas chemical doesn't need to recharge, only refuel after 100-300 firings.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Professor Bell, in spite of all his cynicism, makes some good points (and misses the mark a few times as well, IMHO.) The fact that funding will not open up until 2010 is disturbing, as Apollo and Saturn were both successful because Washington didn't cut corners with development funding. And CEV will be different from Apollo, without a doubt. But will it still cost $15 bil to develop? This is where I disagree, for many of the same reasons stated by GCN Revenger. Rad-hardened electronics will not add too much more weight, and the thruster leaking should not be too much of a problem (even if it is, we have plenty of experience with hydrogen peroxide monopropellant, hydrogen peroxide + kerosene, and even LOX + alcohol thrusters.)
CEV does not have to be difficult or expensive as long as we stay faithful to Apollo or Big Gemini and replace outdated components as we see fit. Boeing has the right idea with their "Apollo on steroids." After looking at Lockheed's capsule (I call it "circumcized Gemini,") I have to shake my head and ask if they know what they're doing.
Prof. Bell is right when he talks about the risks of long duration lunar exploration. But it now appears that NASA does not plan on a government-funded permanent moonbase once the Mars missions are launched. See [http://www.aviationnow.com/avnow/news/c … s03174.xml]Aviation Now for more.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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The Aviation Now article is encouraging, if NASA chooses that path.
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“Plans for this moonbase don't take into account the real environment of the Moon. For instance, official artwork for both Plan Bush and ESA's similar fantasy program "Aurora" persistently show heroic lunar explorers living in flimsy aluminum tanks (rather like ISS modules) or even inflatable plastic tents (rather like the cancelled TransHab). It seems that people have been working on ISS so long they can't even imagine anything else.
Remember that big solar flare storm back in November 2003? That event would have quickly killed anybody in an inflatable hab module or even a 3mm aluminum tank. You need to be under at least 2 feet of moon dirt to survive even one major flare, and you might have as little as 20 minutes of warning time to get dug in. And during solar maxima these killer flares happen about twice a year. So any Moon base has to be underground, right from the start. The first thing you send to the moon will be a mobile backhoe to dig in all the other modules as they arrive.” (1) [http://www.spacedaily.com/news/spacetravel-04j.html]http://www.spacedaily.com/news/spacetravel-04j.html
“Using the moon as a proving ground, NASA can progress from Apollo-scale missions to missions that resemble the complexity and duration of the hypothetical "Mars reference mission" developed at NASA years ago for planning purposes, according to Mendell. That mission calls for 500 days spent on the surface of Mars and roughly 500 days spent in transit to and from the planet.” (2)
[http://www.aviationnow.com/avnow/news/c … s03174.xml]http://www.aviationnow.com/avnow....174.xml
It seems to me that if solar flares are such a problem on the moon the will be just as big a problem during the trip to mars. This is especially true if the crew is spending 500 days in space. Who is right? What kind of shielding is necessary.
Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]
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“Plans for this moonbase don't take into account the real environment of the Moon. For instance, official artwork for both Plan Bush and ESA's similar fantasy program "Aurora" persistently show heroic lunar explorers living in flimsy aluminum tanks (rather like ISS modules) or even inflatable plastic tents (rather like the cancelled TransHab). It seems that people have been working on ISS so long they can't even imagine anything else.
Remember that big solar flare storm back in November 2003? That event would have quickly killed anybody in an inflatable hab module or even a 3mm aluminum tank. You need to be under at least 2 feet of moon dirt to survive even one major flare, and you might have as little as 20 minutes of warning time to get dug in. And during solar maxima these killer flares happen about twice a year. So any Moon base has to be underground, right from the start. The first thing you send to the moon will be a mobile backhoe to dig in all the other modules as they arrive.” (1) [http://www.spacedaily.com/news/spacetravel-04j.html]http://www.spacedaily.com/news/spacetravel-04j.html“Using the moon as a proving ground, NASA can progress from Apollo-scale missions to missions that resemble the complexity and duration of the hypothetical "Mars reference mission" developed at NASA years ago for planning purposes, according to Mendell. That mission calls for 500 days spent on the surface of Mars and roughly 500 days spent in transit to and from the planet.” (2)
[http://www.aviationnow.com/avnow/news/c … s03174.xml]http://www.aviationnow.com/avnow....174.xmlIt seems to me that if solar flares are such a problem on the moon the will be just as big a problem during the trip to mars. This is especially true if the crew is spending 500 days in space. Who is right? What kind of shielding is necessary.
My current opinion is that lots and lots of water shielding (combined with hydrogen rich plastics with added boron) is the only certain defense. Keep metal structures to a minimum near the crew compartments to minimize secondary radiation.
Until we exploit water found "out there" we must carry it up from Earth. But remember, the Marsian south pole has massive water ice. And if Phobos or Deimos have ice deposits, those deposits are closer to LEO (in terms of deltaV) than Earth.
IMHO, Bell is wrong about the inflatable hab modules being unsafe IF the layers include significant water ballast along with thick layers of hydrogen rich plastics.
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Plan #1 is to have a wall several inches thick of water or ice around the habitat which will take the edge off it, and then have an inch or two aluminum and/or polymers, which are good at blunting charged particles, then the last line of defense would be the "storm cellar" which would be made of thick walls of doped polymer or more metal... some work being done on using magnets to deflect some a solar flare as well, but i'd like these to be a "nice addon" and not relied upon.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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And no, Bell is wrong about the TransHab being unsafe because he doesn't know a d**n thing about modern polymers. Modern polymers (kevlar, for instance) are superior to metals, and are flexible to handle impacts better...
In fact, if CEV is to be a capsule, I would like to see it in a Soyuz arrangement with a baby transhab as the service module. Its flexible, inflatable structure would make it easy to pump the skin full of water too.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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I don't really see the point of having an infaltable service module on the CEV. All that complexity mnakes litte sense for individual missions. I'd rather have no service module of any kind on the CEV. Why carry another expendable piece? The crew can certainly tough it out for trips as far as the moon - and both LM and Boeing CEV designs will be a bit roomier that Apollo (and much more than Soyuz) anyway. The CEV should be as light and simple as possible - with a 5m base diameter, there will still be plenty of space.
Inflatable habitats makes perfect sense for semi-permanent habitats/space station components/transfer habitats, though, I think.
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I don't really see the point of having an infaltable service module on the CEV. All that complexity mnakes litte sense for individual missions. I'd rather have no service module of any kind on the CEV. Why carry another expendable piece? The crew can certainly tough it out for trips as far as the moon - and both LM and Boeing CEV designs will be a bit roomier that Apollo (and much more than Soyuz) anyway. The CEV should be as light and simple as possible - with a 5m base diameter, there will still be plenty of space.
Inflatable habitats makes perfect sense for semi-permanent habitats/space station components/transfer habitats, though, I think.
I don't believe room/space is the only issue. Radiation is a killer and hydrogen (whether trapped in plastic or water) is the only known defense.
Secondary radiation scares the heck out of me and building a CEV that is only safe for short trips beyond LEO seems counterproductive.
Using TransHab as the starting point for CEV design advances the engineering legacy we will need to design Mars craft, whether chem propelled or nuke propelled.
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Dr. Bell [http://www.spacedaily.com/news/spacetravel-04i.html]strikes yet again! If this guy ever went to slashdot, he'd be King Troll in no time. Read this:
This problem is so scary and so intractable that nobody wants to hear the unpleasant facts about it. So it isn't any surprise that the "space journalism" community has mostly missed the most important news story since the Columbia crash: the near-destruction of the International Space Station by an orbital debris strike at 2:59 AM Eastern Time on 26 November 2003, and the narrow escape of the two crewmen from unpleasant deaths.
On the surface, the Nov. 26 event seems harmless enough. The caretaker crew of the ISS heard a loud noise described by Michael Foale as "like a metal can being crushed and then unfolded." A careful examination of the Station showed no defects (except of course the dozens of failures in major systems that have already accumulated over the scant five years since construction began). So NASA in its traditional way has declared this event a non-problem since no one was killed.
Transhab, of course, with plastic self-sealing layers goes a long way to solve this problem.
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I think HLLV is going to happen, if for no other reason than Prometheus is the wet dream of every warmongering president since Regan. And they are going to need an HLLV to get the darn thing up where it can be useful.
I'm not sure what project "prometheus" you are referring to - But NASA's project prometheus - now incorporated into the JIMO program will not require a HLLV at all. Current plans call for it to launch on top of a Delta IV-Heavy, and the unfold in LEO to its full 25+ m length.
Read this new [http://www.spacedaily.com/news/spacetravel-04i.html]Dr. Bell piece about the need for shuttle C to actually do JIMO.
The orbital debris menace also seems to be the reason for proposed changes to the mission plan for the JIMO Jupiter spacecraft. This mission was supposed to be launched into a low parking orbit on a Delta 4H or Atlas 5H booster, and then use the new Prometheus nuclear-ion spacedrive to slowly spiral up out of the Earth's gravity well over a period of two years.
But the new plan is different. According to Space.com: "However, those two years of exposure to the space environment - rife with human-made orbital debris, meteoroids, and intense radiation belt hazards - are among issues that have moved NASA to consider putting JIMO on an escape velocity shortly after launch."
Of course, the hazard from meteoroids is trivial and no larger near the Earth than in deep space. And a spacecraft designed to orbit Europa will have to be so rad-hard that it won't even notice the Earth's Van Allen Belts. The only danger cited that could possibly have caused this huge change in the JIMO flight plan is "human-made orbital debris".
A look at the preliminary design concepts for the Prometheus drive module reveals that it is particularly vulnerable to space debris -- far more so than anything launched before. Prometheus requires huge radiators to dump the waste heat from its nuclear reactor. A tiny puncture in any of many small pipes in these radiators would cause loss of coolant and reactor shutdown -- or meltdown. Coolant is already leaking from several Soviet reactors that were abandoned in high orbits in the 1970s and 1980s, probably due to debris impacts.
Even worse, the feeble thrust of the Prometheus ion engines will only gradually lift JIMO through the debris band around the Earth. It will climb up through the clutter zone on a long spiral orbit that will cross paths with almost ever screw and paint chip ever lost by a LEO satellite. It takes decades for an average 1-cm fragment to be pulled down to Space Station altitude by atmospheric drag, but JIMO will climb up and pass them all within a few months. It is easy to see why NASA wants to put JIMO directly onto an escape trajectory with a chemical rocket before starting the reactor.
And this change is not a trivial one. Adding a chemical escape stage pushes up the weight of JIMO from 26 tonnes to 50 tonnes -- far beyond the capacity of any existing booster. The planners are now hoping that NASA will develop Shuttle-C or some other heavy-lift booster and give them one for JIMO.
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Bell also challenges the potential usefulness of LEO for extended on orbit assembly especially if the debris field threat grows over time. He claims no one is calculating debris field threats expected during the next 20 to 50 years.
If we need to assemble at L-1 and with launchers passing quickly through the lower orbit debris, EELVs just won't be big enough to do the job.
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Secondary radiation scares the heck out of me and building a CEV that is only safe for short trips beyond LEO seems counterproductive.
But the CEV is only intended for short trips by itself. Noone is planning to go to Mars just in a CEV - that's where the CEV is attached to the larger habitat. (preferrably TransHab-type). In a Mars mission, the CEV would only be an Earth return vehicle - nothing more. (See Boeing's speculative [http://boeingmedia.com/images/one.cfm?image_id=8864]Mars spacecraft - note CEV w/ Service module on top, and a separate TransHab habitat)
If (presumably) the TransHab has a radiation shelter, that's where the crew would hide out, not the tiny CEV that is attached. Secondary radiation will always be a factor, no matter what kind of Mars mission is proposed, since it will be a practical impossibility to radiation shield the whole spacesraft.
The CEV is only a piece of the Mars plan puzzle. Just think of it as a short-range shuttle / emergency escape vehicle. Nothing more, nothing less. That is all it should be. Just a piece of a modular puzzle.
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Secondary radiation scares the heck out of me and building a CEV that is only safe for short trips beyond LEO seems counterproductive.
But the CEV is only intended for short trips by itself. Noone is planning to go to Mars in just in a CEV - that's where the CEV is attached to the larger habitat. (preferrably TransHab-type). In a Mars mission, the CEV would only be an Earth return vehicle - nothing more. (See Boeing's speculative [http://boeingmedia.com/images/one.cfm?image_id=8864]Mars spacecraft - note CEV w/ Service module on top, and a separate TransHab habitat)
If (presumably) the TransHab has a radiation shelter, that's where the crew would hide out, not the tiny CEV that is attached. Secondary radiation will always be a factor, no matter what kind of Mars mission is proposed, since it will be a practical impossibility to radiation shield the whole spacesraft.
The CEV is only a piece of the Mars plan puzzle. Just think of it as a short-range shuttle / emergency escape vehicle. Nothing more, nothing less. That is all it should be. Just a piece of a modular puzzle.
Wouldn't a plastic CEV or adding TransHab to ISS be good practice and experience for a Mars capable vessel?
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Wouldn't a plastic CEV or adding TransHab to ISS be good practice and experience for a Mars capable vessel?
Re: TransHab - Most certainly - NASA actually tried to replace the ISS Hab module with TransHab a couple of years ago. Congress unfortunately shot that down real fast, suspecting that NASA was trying to use parts of the ISS budget for a Mars mission development. (Which had not been approved at that time)
Now of course it looks like there won't be *any* Hab module attched to ISS. Node 3, if it ever flies, will be outfitted as a partial US Hab module.
BTW, has there been any study about how serious this potential metal secondary radiation from solar flare problem really is? Just curious, becaus every single Mars mission plan I have seen seems to ignore it completely, just opting for a small "storm shelter" compartment.
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Here is an interesting tidbit. Body armor worn by US soldiers in Iraq is fashioned from boron carbide.
Boron carbide is very hard and a neutron absorber (secondary radiation?). Start with TransHab and add pockets to the final inner layer of kevlar and fill those pockets with ceramic plates made from boron carbide - B4C.
Secondary radiation and debris protection in one package.
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LarsJ - - Here is one link:
[http://helios.ecn.purdue.edu/~tatjanaj/ … ort-12.pdf]http://helios.ecn.purdue.edu/~tatjanaj/ … ort-12.pdf
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Bell and Nasa are probably overreacting to the threat of space debries, we don't really know how much little stuff is up there, and it is quite possible to defend against the really tiny stuff... i'm sure we could invent a leak resistant radiator system if Nasa abandoned ubersafe low-temperature coolants. We've got Whipple shields for the rest of the structure's soft spots.
Getting used to (mass) producing and operating TransHab modules would be a nice thing I would think, since they are almost certainly going to be the next Hab module wherever we go... And in defense of metals, Aluminum isn't so bad about producing secondary particle radiation, and you can build your rocket out of it... free shielding. Polymeric materials rich in hydrogen are nice, but for anything except TransHab they are dead weight. Boron carbide is nice thanks to its hardness, but you don't want it too hard, TransHab was planned to have several inches of foam between inner and outter layers to slow down impact materials gradually. Boron also isn't as good as other materials for stopping charged particle radiation... it would work fine as a dopant for polymer shielding to improve its blocking though.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Bell and Nasa are probably overreacting to the threat of space debries, we don't really know how much little stuff is up there, and it is quite possible to defend against the really tiny stuff... i'm sure we could invent a leak resistant radiator system if Nasa abandoned ubersafe low-temperature coolants. We've got Whipple shields for the rest of the structure's soft spots.
Getting used to (mass) producing and operating TransHab modules would be a nice thing I would think, since they are almost certainly going to be the next Hab module wherever we go... And in defense of metals, Aluminum isn't so bad about producing secondary particle radiation, and you can build your rocket out of it... free shielding. Polymeric materials rich in hydrogen are nice, but for anything except TransHab they are dead weight. Boron carbide is nice thanks to its hardness, but you don't want it too hard, TransHab was planned to have several inches of foam between inner and outter layers to slow down impact materials gradually. Boron also isn't as good as other materials for stopping charged particle radiation... it would work fine as a dopant for polymer shielding to improve its blocking though.
Keeping eyes on the next step is part of why I favor looking at a TransHab inspired CEV crew compartment. Using current steps to leverage next steps is why I favor shuttle derived for ISS completion.
Also, Dr. Bell may well be an alarmist however that November 2003 incident was very real and it seems we just dont know how much smaller orbital debris there is. And I believe he is right in saying that if orbital debris had killed the two ISS crew in November 2003, the politics for future manned spaceflight would be VERY bad in the near term.
At another site it was also suggested that much of this debris might very well explode and combust upon entry into an oxygen rich ISS module - - but not to worry about that since the sudden decompression would resolve the fire and toxic combustion products. ???
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Re: TransHab - Most certainly - NASA actually tried to replace the ISS Hab module with TransHab a couple of years ago. Congress unfortunately shot that down real fast, suspecting that NASA was trying to use parts of the ISS budget for a Mars mission development. (Which had not been approved at that time)
Astronautix.com reports that Transhab was shelved because it cost just as much as the metal hab. Ultimately, both alternatives for ISS habitation were cancelled due to ISS cost overruns. But it may be possible to use the aegis of "lunar-Mars exploration" to justify spending money on the new hab.
My thought regarding the CEV is that it should be used only for the initial launch from Earth and for Earth entry. Sealed thrusters would be kept until needed, as in the Big Gemini proposal.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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Re: TransHab - Most certainly - NASA actually tried to replace the ISS Hab module with TransHab a couple of years ago. Congress unfortunately shot that down real fast, suspecting that NASA was trying to use parts of the ISS budget for a Mars mission development. (Which had not been approved at that time)
Astronautix.com reports that Transhab was shelved because it cost just as much as the metal hab. Ultimately, both alternatives for ISS habitation were cancelled due to ISS cost overruns. But it may be possible to use the aegis of "lunar-Mars exploration" to justify spending money on the new hab.
Suppose it cost the same as metal. Isnt it a superior system?
[http://www.hobbyspace.com/AAdmin/archiv … Adams.html]Interview with Constance Adams
This quote is dated May 2003:
Many trade studies were then performed to determine which choice would better suit the ISS’ immediate needs and current budgetary constraints. In terms of long-term and operational costs and needs, there was no question that the ISS-TransHab module would save the program tens or hundreds of millions of dollars over the first decade, and would give the overall Station several assets that it does not and could not otherwise have. These included a safe-haven shelter for solar storms, on-orbit water recycling capability, more than double its current total stowage volume, and the ability to test new exploration-class technologies like a human centrifuge, advanced medical facilities and lighting as well as the inflatable shell and orbital-debris shielding for which TransHab has become famous. NASA’s Human Exploration and Development of Space (HEDS) roadmap defines all of these technologies as essential developments for any long-duration human expeditions beyond earth orbit, such as a return to the Moon or the exploration of Mars.
However, you are right in understanding that the discovery in early 2001 of a $4.8B shortfall in the ISS budget has had wide-ranging effects in America’s overall space program, almost all of them very damaging. One of the first things to be cut from the program was the habitation module and supporting elements of the ISS, including the Crew Return Vehicle which would be necessary to allow the crew to grow from 3 to 7.
Currently there are no NASA efforts I know of to develop any space inflatables, but this does not rule out the possibility of recovering this program if and when the funding scenario changes or another mission is found for similar vehicles.
Does anyone know if inflatable programs have been started up again?
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It certainly is superior for spaceflight, you just can't launch with it deployed.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Here is an interesting event. I went into the Constance Adams interview again and attempted to click enlarged images of TransHab drawings. Just curious, frankly.
I was told that these images were not available and that a program called robot.txt had prevented cached versions from being saved on other, non-NASA servers.
Does anyone know more about this phenonemon?
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That does sound a little fishy, though I won't go so far as to link it with the theory that exploration is not what Nasa wants...
Nasa, being a huge organization employing dozens of thousands of people, first and foremost wishes to preserve the employment of said people. So, the obvious thing to do is to make a project that employs them for an indeterminate amount of time with a budget that cannot be cut without signifigant political bloodletting.
So, we got Shuttle, and its evil stepchild the ISS. Nasa needed somthing to do after Apollo, somthing that would keep Michoud, KSC, etc open.Imagine their delight at this phrase:
"Large space station... 30+ Shuttle launches required... lifespan of 15-20+ years... modularity leading to future expansion and continual increasing need for cargo and crew flights."
Nasa knew very well when they decided on Shuttle's tank/booster/orbiter configuration that it would become a nightmare to fly and would become ungodly expensive... and thats why Nasa loved it. Shuttle/ISS has kept the jobs of dozens of thousands of engineers and technitions employed for about twenty five years now, and it will hit thirty before its done. Shuttle/ISS is Nasa's gravy train... expensive, long term, uncancelable.
And anything. Anything that possibly threatend this central, core money maker was anathema... Going to Mars without buckets of extra money would require ISS be canceld or curtailed, and then what would you need Shuttle for? Same thing with the DC-X, which would make a dandy light cargo frieghter, but it was stabbed in the back by Nasa too. The X-33 VentureStar was too ambitious at the get-go, and I think Nasa knew it, which is why they started it: "oh, replacing Shuttle is too hard, lets forget about a replacement". TransHab, a Mars/Moon technology, would reduce the "inertia" to go elsewhere besides LEO. And now Prometheous/JIMO, they are getting all silly about armoring the thing and adding a booster so Nasa gets the nod to build Shuttle-C/Z even though it probably isn't needed for it (even though it would be dandy for exploration) hence keeping KSC/Michoud open and minimizing EELV competition.
Nasa is hell bent to save the status quo, by any means nessesarry.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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And anything. Anything that possibly threatend this central, core money maker was anathema... Going to Mars without buckets of extra money would require ISS be canceld or curtailed, and then what would you need Shuttle for? Same thing with the DC-X, which would make a dandy light cargo frieghter, but it was stabbed in the back by Nasa too. The X-33 VentureStar was too ambitious at the get-go, and I think Nasa knew it, which is why they started it: "oh, replacing Shuttle is too hard, lets forget about a replacement".
DC-X had a lot going against it. There was opposition within the Strategic Defense Initiative to flying it, so its SDIO flight test program was curtailed. NASA saved the vehicle, but their internal design studies (based on questionable assumptions) and the "Not Invented Here" syndrome led NASA to choose Lockheed's X-33 over further developments of DC-X. With X-33 representing "the future," NASA saw little impetus to continue the DC-X flight program, especially after the DC-X was destroyed. Logical plans to expand the DC-X test envelope with the DC-XB and DC-XC died a quiet death.
Of course, NASA's questionable design assumptions were revealed with the failures of the X-33. I disagree with Jeffrey Bell's assertion that composites are unsuitable for spacecraft, as DC-X successfully flew with a composite fuel tank. It's just that Lockheed lacked the experience to fabricate the complex composite fuel tanks demanded by the X-33.
The X-33's failure dealt RLV's a serious setback (which can be debated further in the RLV thread.)
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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[http://www.spaceref.com/news/viewnews.html?id=938]Dennis Wingo takes his shots at the two most recent articles by Jeff Bell.
My thoughts are more in line with those of Wingo than those of Bell (particularly when Bell talks about how hard and expensive it will be to build the CEV,) but it is good to see some spirited debate that will hopefully be heard by the Aldridge Commission.
My biggest qualm with Dennis Wingo is that he advocates using ISS to assemble spacecraft, while I fall in the camp of HLLV-lovers. Perhaps a happy medium can be found if two Shuttle-C launches are needed for each spacecraft (using 57-tonne direct-landing spaceships,) and the two pieces would be docked to each other in orbit or at ISS.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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[http://www.spaceref.com/news/viewnews.html?id=938]Dennis Wingo takes his shots at the two most recent articles by Jeff Bell.
My thoughts are more in line with those of Wingo than those of Bell (particularly when Bell talks about how hard and expensive it will be to build the CEV,) but it is good to see some spirited debate that will hopefully be heard by the Aldridge Commission.
My biggest qualm with Dennis Wingo is that he advocates using ISS to assemble spacecraft, while I fall in the camp of HLLV-lovers. Perhaps a happy medium can be found if two Shuttle-C launches are needed for each spacecraft (using 57-tonne direct-landing spaceships,) and the two pieces would be docked to each other in orbit or at ISS.
Can EELVs possibly finish ISS?
I recall clark was going to contact Boeing about using Delta IV to ISS yet my memory is that while the extended payload fairing offers the same volume as the orbiter cargo bay and while Delta IV can throw approximately the proper mass to the ISS orbit, there is no last mile guidance and no extra mass allowance within Delta IV to design last mile guidance.
A shuttle C idea would be to add rudimentary station keeping to allow a Progress to act as tug using the ISS robot arm for assembly or dock orbiter with shuttle C for the last mile to ISS.
A rule of thumb appears to be that shuttle C can carry two ISS paylaod by volume and three by mass except trusses can only be carried one at a time for volume reasons.
One truss via orbiter and 2 nodes or modules via shuttle C may be the most efficient architecture.
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It would be possible to finish ISS with Proton, just like the Russians did when Mir was built. The modules would need to be modified so a Progress could be connected for steering them to the ISS. Presumably the same could be done with a Delta IV or Atlas V Heavy. Any way of reducing the number of shuttle flights to ISS would be appreciated, as every mission is a chance that the program could be terminated should it fail.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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