Anyone going to see the Orion Test Flight?

[luke strawwalker]

No experience with long term viability in low gravity situations. I have been harping on this topic for years and you appear to be the only one who gets it.

There have been astronauts arriving back to Earth whose immune system has been seriously compromised showing many of the same symptoms as people with AIDS. They do get better, sort of, so NASA et all don’t like to talk about it. Women especially suffer from the bone mass loss problem as well as fluid displacement affects that are damn bothersome.

We also have, to my knowledge, no means by which we could protect astronauts traveling in deep space for extended durations from the affects of cosmic rays and or a solar flare/coronal mass ejection.

The only method I’ve read about is some kind of “Storm shelter” the crew could hide-out in for the duration of the event.

Personally I don’t think manned deep space missions will be practical until we can develop a means for the crew to rid themselves of solid waste that doesn’t entail a 37 step process and an instruction manual longer than the L.A. County phone book.

Radiation is another big "?"...

Basically it's two different problems. First you have solar particle events... basically, solar flares send out protons at high fractions of the speed of light during solar flares/coronal mass ejections. These can kill astronauts outright if they get hit by a 'solar storm'. Fortunately, they're *fairly* easy to shield against... since they're coming from a common origin point (the sun) and particularly well stopped by hydrogen, all you really have to do is have a big tank of water or hydrogen propellant to hide in... Either hide in the shadow of the tank (put the tank between your crew module and the sun) or for better protection, have a hollow "storm shelter" inside your tank to ride it out. These solar storms can last for anywhere from minutes, up to weeks, however... so riding out a long-duration storm inside a closet-size shelter inside the spacecraft could be very problematical!

The other problem is far more sinister... galactic cosmic radiation (GCR). These are heavy nuclei (usually iron) ejected from supernovas and accelerated to nearly the speed of light. They come from ALL directions, CONSTANTLY, in a pretty even and steady "rain" of radiation particles. They are insidious because when they hit aluminum or other metals, or organic matter, they tend to break up into a "shotgun blast" spray of secondary particles and radiation. Those secondary particles can do significant damage to the human body, apart from the damage done by the primary particles... These are the 'light tracks' astronauts often reported seeing inside their eyeballs with their eyes closed on the way out to the Moon and back. The only "shielding" that is even somewhat efficient for GCR is a layer of hydrocarbon polymers, ie heavy plastic like polyethylene, which is about as good as it gets for capturing the stray nuclei and secondary particles before they can impact the human body. This has to be placed in a layer inside the aluminum structure of the vehicle's outer pressure hull and surfaces, so that impacting nuclei that break up into a secondary particle spray are captured or slowed by the polyethylene "radiation shielding". Some particles still get through, however, and there really isn't any REALISTIC way to stop them. NASA has been touting research on possible "magnetic shields" that COULD act like Earth's magnetosphere and deflect these particles around the shield, just as Earth's magnetic field does, but it would take an ENORMOUS amount of power and would require decades of research to produce a viable operational unit... powering it is a whole other issue...

As if that weren't enough, the real basic problem with a Mars mission is basically what you mentioned last... consumables and waste. Humans need SO much air, water, food, etc. and produce so much waste that has to be eliminated for them to survive (CO2, feces, urine) that basically a closed life support system will HAVE to be developed in order for the ship mass and cargo requirements to be kept realistic... and we're not doing hardly ANYTHING like that... We recycle water on the station, from sweat, urine, and condensation from the atmosphere into drinkable water, and the Russians have a carbon dioxide removal system (Voronezh IIRC) that does not use consumables (lithium hydroxide beds), and their Elektron oxygen generator systems, but much beyond that, EVERYTHING comes up from Earth... and gets tossed overboard when its done. Right now, pretty much EVERYTHING the astronauts use in day-to-day life, from food and clothing to personal hygiene materials and other consumables, are sent up from Earth on periodic resupply missions by various craft, be it the Russian Progress, European ATV, Japanese HTV, SpaceX Dragon, or OSC Cygnus. Astronauts wear their clothing ONCE, then throw it away. There is no "space laundry" in orbit. All this "junk" ends up being stowed in the resupply modules when they're done, and when full, they 'cast off' from the station and burn up in the atmosphere with their load of trash (well, except for Dragon, which comes back with whatever they put aboard). This mode of operation simply WILL NOT WORK for a 2-3 year Mars mission... the required payloads and vehicle size to push through TMI (Trans-Mars Injection) is simply too high for any realistic missions (realistic to be funded anyway). Yet, there is little/no work being done in this direction either... the system works 'well enough' for ISS, and there isn't money for anything else, and they don't want to divert funding from SLS/Orion or ISS to do it...

Yet, SOMEHOW, all the 'cheerleading' that goes on in NASA press releases and "plans" and announcements proclaim loudly how "we're going to Mars!" as if all these sorts of problems are just going to miraculously solve themselves...

Later! OL JR

 

[luke strawwalker]

On another topic, at the missile museum at the Canaveral air force base, the gift shop was selling Dr. Zooch EFT-1 kits The display model was very nicely done.

Frank

I built that model for Wes to send to the museum... thank you! Did the Explorer I too...

Later! OL JR

 

[boomtube-mk2]

And then there is power generation. Look at the ISS and all the solar panels it requires to generate enough electricity to run itself. And it’s in Earth orbit.

Now imagine how big the panels would have to be if the ISS was in orbit around Mars or even halfway there.

The only realistic concept I’ve read about getting to Mars is having a series of unmanned/robotic supply ships sent out along the path the manned vessel would take and having them dock with those supply ships periodically as they converge and transship those supplies in-flight.

How realistic is that really? Not very but it’s the best idea I’ve seen which says a lot about the other proposals.
Of course all of this would become irrelevant if we only had a constant boost propulsion system. Something that would allow even a 10th-G acceleration would do nicely.

 

[burkefj]

Excellent, glad to see one of our own had a hand in that!

Frank

I built that model for Wes to send to the museum... thank you! Did the Explorer I too...

Later! OL JR

 

[ThirstyBarbarian]

All of the reasons given for the difficulty in going to Mars are good reasons for focusing the manned effort on going to the moon again, visiting other nearby objects, establishing a lunar base, etc. We still have a lot to learn about how to deal with radiation, micro gravity, partial gravity, long-term life support, etc. A long-term lunar exploration program would provide opportunities to develop those technologies without committing crew to a 2-year mission with no way out. And I think the moon will have significant resources as well that will help to support longer missions to more far away objects in the future.

I'm fascinated by mars, and I think we must go there, and we will. But there are major difficulties in accomplishing a mission, and we can learn how to solve those problems closer to home. In the meantime, there is a lot we can learn from the robotic missions to Mars and other destinations.

 

[boomtube-mk2]

Having a manned long term research station on the Moon would provide data as to whether humans can survive/prosper in a low G environment, as opposed to Earth norm or zero/micro-gravity. Living at a lower than normal gravity is something we know nothing about as of today.

The one bit of research that needs to be pursued with all bells ringing is either an ion or nuclear propulsion system.

Many of the problems with deep space manned missions disappear or are at least highly reduced, if we can get where we are going in days or weeks instead of months or years.

 

[RAHagen]

Solar power would be completely impractical. I personally believe the only way we'll be able to go any farther than the moon and have enough power to maintain life is if we develop some sort of nuclear power source. A nuclear power source could run the craft and provide power to an ion propulsion engine if it were powerful enough. What would be cool us if we developed a motor that provided a whole G of acceleration. If we had that our problems of micro-gravity would be solved. The power required to produce that however would probably be tremendous.

So pretty much all our problems would be solved with an matter/ anti-matter engine!

 

[ThirstyBarbarian]

Having a manned long term research station on the Moon would provide data as to whether humans can survive/prosper in a low G environment, as opposed to Earth norm or zero/micro-gravity. Living at a lower than normal gravity is something we know nothing about as of today.

The one bit of research that needs to be pursued with all bells ringing is either an ion or nuclear propulsion system.

Many of the problems with deep space manned missions disappear or are at least highly reduced, if we can get where we are going in days or weeks instead of months or years.

I agree. Reduced gravity is different from micro-gravity, and maybe the effects are not the same. We should find out. And advanced propulsion systems that cut the trip time significantly are the key to opening up the solar system.

 

[boomtube-mk2]

The problem with nuclear power being used as a source of electricity is it would have to be a completely closed loop system.

Electricity derived from nuclear power, even in ships and submarines, uses vast amounts of water in the process.
Heat produced by fission is used to boil water into steam and the steam is used to spin a turbine hooked to a generator. Even more water is used to cool the reactor and condense the steam back into water.

How the heck do you do that aboard a spaceship?

 

[georgegassaway]

The problem with nuclear power being used as a source of electricity is it would have to be a completely closed loop system.

Electricity derived from nuclear power, even in ships and submarines, uses vast amounts of water in the process.
Heat produced by fission is used to boil water into steam and the steam is used to spin a turbine hooked to a generator. Even more water is used to cool the reactor and condense the steam back into water.

How the heck do you do that aboard a spaceship?

Regarding power issues in getting to and landing on Mars

Mars is about 52% farther away from the sun than Earth is. So, with weaker sunlight per square foot, a solar panel needs to have about 2.31 times more surface area to generate the same electrical power, all other things being equal.

ISS has lots of solar panel, but then is sort of a power hog. It's made for experiments that can use a lot of power. Also, ginve the lessons of Skylab, with one missing panel wing, it would make sense ot have more than it needed, either just in case, or to have plenty of margin. For a human Mars trip, the electrical power needs would be optimized for what is needed for that mission and not for running a lot of excess equipment as ISS needs to.

Also, for the trip out and back, a Mars ship can have its panels in sunlight 100% of the time, while ISS has its panels in darkness for nearly half of each orbit (work out the geometry of a space station in orbit 268 mile above the earth to see why it's not exactly 50%)

Of course it would also be prudent to have some excess solar panel area in case a couple went bad along that way, as well as designing the systems so that in case of a severe problem they could still survive if say they lost half the power, just might not be using laptops to watch movies anymore…….

But in any case, solar panels are relatively lightweight and pretty well developed, so I don't see much of an issue in having enough panels to be able to run a spacecraft to Mars and back. After all, we and the Russians have been doing that for decades with other missions to Mars, albeit without the demands of life support.

Now, after a landing none of us will probably live to see (Unless Elon Musk does the incredible, I've not given up on NASA but have given up on NASA ever being given the funding and national directive to actually do so like Apollo was) , it could be problematic to have a "farm" of a bunch of solar panels that could be destroyed by the wind storms that frequent Mars. There are also "Dust Devils" on Mars. The craft that have landed on Mars, their solar panels are usually mounted to a solid surface.

Nuclear power in space…… there are two totally different sane types of nuclear power (I discount the Project Orion concept of tiny nuclear explosions going off behind a shock absorber equipped ship). One, for propulsion, is the NERVA type engine that uses a nuclear core to get a working fluid (such as hydrogen, but it could be WATER, but hydrogen is more efficient) so hot that it spews out like a hyper steam at extreme velocity. That is the propulsion that might help make the trip shorter.

But for electrical power forget the method used on Earth for nuclear power plants or even on ships and submarines. Spacecraft use RTG's, Radioisotope Thermoelectric Generators.

https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator

https://solarsystem.nasa.gov/rps/rtg.cfm

Several spacecraft have used RTG's, including the Viking Landers, Galileo, Cassini, Voyagers, and some Apollo lunar missions (ALSEP).

- George Gassaway

 

[luke strawwalker]

And then there is power generation. Look at the ISS and all the solar panels it requires to generate enough electricity to run itself. And it’s in Earth orbit.

Now imagine how big the panels would have to be if the ISS was in orbit around Mars or even halfway there.

The only realistic concept I’ve read about getting to Mars is having a series of unmanned/robotic supply ships sent out along the path the manned vessel would take and having them dock with those supply ships periodically as they converge and transship those supplies in-flight.

How realistic is that really? Not very but it’s the best idea I’ve seen which says a lot about the other proposals.
Of course all of this would become irrelevant if we only had a constant boost propulsion system. Something that would allow even a 10th-G acceleration would do nicely.

This is true... solar energy availability on/around Mars is only HALF the solar power available at Earth... SO you need TWICE as much area in solar cells to generate the same amount of power that a given size solar panel can generate at Earth. (inverse square law). This is even more pronounced for surface systems, because you have to generate enough power to also run everything at night... so you need FOUR TIMES the solar generating capacity as you would for a similar outpost on Earth generating power only during the day...

Some sort of electric propulsion or ion drive that can generate a slow but steady ultra-high efficiency thrust would be great... but not particularly likely... Ion and other electric propulsion systems don't produce much thrust AT ALL, and require large amounts of power to operate... For a lightweight probe (like say Deep Space One) the low thrust isn't that big of an issue. When you're talking about a MANNED space vehicle bound for Mars weighing say 1000 tonnes, (which is roughly where most of the Mars Design Reference Missions put the IMLEO of the outbound spacecraft stack), then you're going to need ENORMOUS clusters of electric thrusters to generate enough thrust to generate meaningful acceleration levels. Then of course you'll need fuel for them...

Nuclear thermal rockets can overcome this problem-- they can produce large levels of thrust very easily, and are MUCH more efficient from a power-density standpoint than electric systems, whether they be nuclear electric propulsion, or solar electric... Good luck getting that funded, developed, and flown, though... The renewed Prometheus nuclear propulsion research program brought back in the early days of the VSE was cancelled almost before the ink was dry...

Again, this is all the kind of research NASA SHOULD be doing to facilitate manned deep space missions... and a sustainable presence there... Yet virtually NONE of it is being done, and NO development projects are approved or funded...

LateR! OL JR

 

[luke strawwalker]

All of the reasons given for the difficulty in going to Mars are good reasons for focusing the manned effort on going to the moon again, visiting other nearby objects, establishing a lunar base, etc. We still have a lot to learn about how to deal with radiation, micro gravity, partial gravity, long-term life support, etc. A long-term lunar exploration program would provide opportunities to develop those technologies without committing crew to a 2-year mission with no way out. And I think the moon will have significant resources as well that will help to support longer missions to more far away objects in the future.

I'm fascinated by mars, and I think we must go there, and we will. But there are major difficulties in accomplishing a mission, and we can learn how to solve those problems closer to home. In the meantime, there is a lot we can learn from the robotic missions to Mars and other destinations.

Exactly right!

Instead of a serious, sustainable plan for accomplishing things, though, we get goofy speeches about "been there, done that"...

Later! OL JR

 

[luke strawwalker]

The problem with nuclear power being used as a source of electricity is it would have to be a completely closed loop system.

Electricity derived from nuclear power, even in ships and submarines, uses vast amounts of water in the process.
Heat produced by fission is used to boil water into steam and the steam is used to spin a turbine hooked to a generator. Even more water is used to cool the reactor and condense the steam back into water.

How the heck do you do that aboard a spaceship?

That's only one model of reactor-- the Pressurized Water Reactor (or Boiling Water Reactor, which were common in Europe-- the US only used PWR's). There are about at least a dozen different reactor designs. The Soviets have developed and flown (IIRC) some small reactor designs which would be good for surface systems... IIRC their reactor design was called "Timberwind".

The problem with a nuclear reactor is that MOST of its power is delivered as THERMAL energy. If you're using that thermal energy to DIRECTLY heat a propellant gas (say Hydrogen) and expelling that propellant through a nozzle, you can get highly efficient high thrust rocket propulsion, capable of accelerating a high-mass spacecraft stack. This is basically a "NERVA" type nuclear rocket engine. You get a lot of thrust and power for a relatively small reactor. If you have to convert that THERMAL energy into ELECTRICITY, the system gets MUCH more complex, much heavier, and much more inefficient. In fact, you have to multiply the size of the reactor by several times to provide the same amount of power, due to the losses and inefficiency in converting the thermal energy into electrical energy, and then massive clusters of ion or Hall-effect thrusters to make sufficient thrust. All that adds enormous mass to the spacecraft stack, which of course requires more fuel, etc...

Now, I've read about some nuclear rocket engines that operate in BOTH cycles... it can produce nuclear thermal rocket thrust for high-thrust applications, then go into a low-power cycle to produce electricity to power the mission. Something like that is what will realistically be needed.

Another huge issue is SHIELDING. It's not insurmountable, but it's not a small issue, either.

ALL of this stuff is REALLY spelled out in "The Case for Mars" by Robert Zubrin. Whether you agree with his "solutions" or not, it IS a wonderful read and he really spells out the issues that will have to be dealt with, including propulsion, radiation, travel times, microgravity, artificial gravity, etc...

Later! OL JR

 

[ThirstyBarbarian]

Regarding the issue of space-based solar panels and weaker sunlight at further distances from the sun, you can make up for that by using reflectors to concentrate sunlight. Very thin lightweight reflective films, like what might be used for a solar sail, could be used to increase the area of sunlight collected. It would be of no use on the surface of Mars, but could be used in orbit, in transit, or on the surface of some airless moons or asteroids.

 

[Peartree]

Regarding the issue of space-based solar panels and weaker sunlight at further distances from the sun, you can make up for that by using reflectors to concentrate sunlight. Very thin lightweight reflective films, like what might be used for a solar sail, could be used to increase the area of sunlight collected. It would be of no use on the surface of Mars, but could be used in orbit, in transit, or on the surface of some airless moons or asteroids.

It might also help to remember that nearly every ISS resupply mission has a bank of solar panels that are jettisoned before reentry. I would think that with a little redesign these could me made to be detachable and transferred as a "Mars mothership" was being constructed. Each mission carrying parts and supplies would also be carrying solar panels anyway, so why not make them dual use?

 

[luke strawwalker]

It might also help to remember that nearly every ISS resupply mission has a bank of solar panels that are jettisoned before reentry. I would think that with a little redesign these could me made to be detachable and transferred as a "Mars mothership" was being constructed. Each mission carrying parts and supplies would also be carrying solar panels anyway, so why not make them dual use?

In HOW MANY DECADES??

Those things DO deteriorate over time... ESPECIALLY in higher radiation environments...
By the time you got around to trying to cobble together your spare parts solar arrays, they'd probably be junk anyway.

Besides, can you really see *NASA* cobbling together spare parts stored on orbit for years for a MANNED mission?? Of course not...

Besides that, a cobbled together solar array (that might quit when you need it the most) would also be a LOT heavier than a dedicated-built solar array for the same amount of power...

Later! OL JR

 

[Peartree]

In HOW MANY DECADES??

Those things DO deteriorate over time... ESPECIALLY in higher radiation environments...
By the time you got around to trying to cobble together your spare parts solar arrays, they'd probably be junk anyway.

Besides, can you really see *NASA* cobbling together spare parts stored on orbit for years for a MANNED mission?? Of course not...

Besides that, a cobbled together solar array (that might quit when you need it the most) would also be a LOT heavier than a dedicated-built solar array for the same amount of power...

Later! OL JR

I'm not talking about storing them for decades, but deliberately designing them for dual use so that the craft that are carrying/ferrying the parts to orbit *during assembly* of the long distance/long duration craft don't have to pay the cargo weight premium twice. They need them for the cargo ship, but when they are done, instead of burning up on reentry, they are transferred to the ship under construction. Not "cobbled together" but "designed for dual use."

Just a thought though, now that ISS has been in orbit for a while, just how old are its solar panels, or those of some of our older satellites? Is age even a problem for solar panels? I don't think that age is as much of an issue as design.

Either way, I don't expect it to happen in my lifetime. NASA and the US government playing smart? Not gonna happen.

 

[luke strawwalker]

I'm not talking about storing them for decades, but deliberately designing them for dual use so that the craft that are carrying/ferrying the parts to orbit *during assembly* of the long distance/long duration craft don't have to pay the cargo weight premium twice. They need them for the cargo ship, but when they are done, instead of burning up on reentry, they are transferred to the ship under construction. Not "cobbled together" but "designed for dual use."

Just a thought though, now that ISS has been in orbit for a while, just how old are its solar panels, or those of some of our older satellites? Is age even a problem for solar panels? I don't think that age is as much of an issue as design.

Either way, I don't expect it to happen in my lifetime. NASA and the US government playing smart? Not gonna happen.

Umm..kay. Which is it?? I'm confused... One minute you're saying "not cobbled together" and the next minute you're talking about ISS solar panels and old satellite solar panels. You can forget about that IMHO.

As for "dual use"... okay, I get that. Makes a certain amount of sense. BUT, WHO is going to be around to detach the things and store them. Building up a mission in orbit will take YEARS of launches at the flight rates NASA is talking about for SLS (which is all they've talked about using-- its SLS' *SOLE* reason for existence!) and these 'cargo flights' won't be accompanied by manned launches every time, or even most of the time. It would be cost-prohibitive. You can buy a LOT of solar panels for what even a "commercial crew taxi" MANNED flight would cost, to send someone up to unplug and store spare solar arrays... Penny wise, perhaps, but DEFINITELY pound-foolish!

You're right though; I don't expect ANY of this to actually happen in my lifetime. Not by a longshot. The realities are SO far apart from the "cheerleading" coming out of NASA in their pressers and statements that its like they're living in a dream world. The political realities are, that it's not likely to get any better. In fact, in all likelihood, it's probably going to get a LOT worse.

The *only* thing I can see that might possibly kick-start the entire thing into a realistic support/funding situation and actually motivate Congress/NASA leadership to actually build and fly something rather than design and study it for decades is if one of our rovers or probes actually turned up something of profound scientific or national importance, or of profound importance to mankind and his understanding of the universe, *coupled* with the Russians or Chinese or whomever being a credible "threat" to get there and/or confirm it first. It would have to be something that basically "required" a human mission to actually confirm the discovery and obtain the scientific data, perhaps expand upon it.

Other than that, I don't see much hope... and I don't REALISTICALLY see the "we gotta go find out what the rover found!" scenario as in any way likely, either... So what DO *I* expect to see?? More of the same, more of the same dithering that NASA has done when it comes to Mars missions for the last 40 years or so.

A manned Mars mission has *always* been 20-30 years in the future. Now is no different. Until I see *evidence* that its different (realistic plans and funding profiles for the necessary hardware, beyond a "super-duper-uber-rocket" mega-expensive development program that amounts to political pork for preferred aerospace contractors, with NO PAYLOADS, let alone a complete exploration infrastructure that will be required for such missions) I'm going to remain convinced that its all an exercise in political pork and cheerleading.

Later! OL JR

PS. BTW-- radiation degradation of ALL electronics is inevitable over time, especially for semiconductor containing electronics (practically everything, including solar arrays). It is especially bad in the space environment, even inside Earth's magnetic field, where electronics (and everything else) is constantly bathed in radiation considerably higher than on Earth's surface or even in airliners).

PPS... a "solar array" made up of multiple scavenged or "dual purpose" units WILL be considerably heavier than a single monolithic solar array of equivalent power. Frames, folding mechanisms, connections, etc. ALL add up! The cost of solar arrays is "down in the noise" for a mission of this complexity and size anyway. Plus, excess mass is the REAL killer for electric propulsion-- more mass=more thrust needed for a given acceleration.

 

[John Done]

I guess pandemic totally ruins NASA plans to launch the first stage of the mission by 2024 and NASA suspends production and testing of Space Launch System and Orion spacecraft. However, they determine the work that staff can do remotely at home, critical work that needs to be done in the field, and fieldwork that will be suspended.