Yet…
Stephen Fleming gave a talk on that subject at Dragoncon this weekend (I should go some time). I haven’t looked at them yet, but his slides are on line, and I suspect there’s some good input to the Kickstarter there.
[Update a few minutes later]
Still haven’t been through slides, but I’m amused to see that he stole my graphical book-cover them in the very first one.
[Reading through]
I’d note that in his slides on the “Martian Defense Grid,” someone on the Mars panel at the AIAA meeting last week called Mars our “Jamestown.” High casualties to initial pioneers.
[Update a few more minutes later]
I wish we could show those charts of the unknown shape of the health/gravity curves to Congress. It makes a powerful case for a gravity lab, but only to people who actually give a damn about Mars. Actually, someone should show them to Elon.
I love the slides.
Rand,
I really hope we can get some data on what the hypogravity health curve really looks like. If SSI can’t get funding for something like G-lab, some of the tech we’re working on at Altius right now might lower the cost down the road for answering the question.
~Jon
If anyone actually was serious about any of this, there would have been multiple rotating sats with rodents on them circling the earth in past few decades.
The fact that there aren’t any indicates that nobody is actually serious about going anywhere in space.
reader,
Rotating sats with rodents on board is harder than it sounds, but I agree with you point–if anyone were serious about space settlement, they would’ve pushed harder on this problem sooner. Hopefully we can change that.
~Jon
Perhaps some data is available – the data from the hyper-G studies in the past tend to indicate that hyper-G is even better for humans than normal G. So that implies that the slope of the line is positive through 1 G, at least.
Of course, that is not saying much. It still could be a wide range of values at 1/6G and 1/3G – but being better than 1 G is unlikely, in my opinion.
Good framing of the problem, yet I think the solution is going to be substantially different.
Dennis,
When you say that you think the solution will be different, do you mean the solution to figuring out what that curve (health vs. gravity) looks like, or dealing with the curve once we understand it? Or were you talking to the general solution of how to get to Mars from here?
Not disagreeing, but curious to hear your thoughts on how to proceed.
~Jon
John
I have a peer reviewed paper out soon on the start of the process. Am still thinking about how to put the next steps on paper. Things have changed substantially since Moonrush came out. It was the why, my next work is how….
Takes a lot of effort though, this ain’t Mars One!
Well, “stole” might be a bit harsh. More like “used the same template that he used last year, which was based on Rand’s book with full credit.” 🙂
http://www.stephenfleming.net/files/Fleming_SafeIsNotAnOption_DC2014.pdf
Yes, I didn’t mean literally “stole” as in w/o permission, nor am I in any way unhappy about it. 🙂
EmDrive == Experimental Error?
That seems to be the on-going hypothesis. But any news of the replication work that was supposed to be happening at Glenn?
Regarding the “EM Drive”, the display of thrust is interesting, but ONLY if it’s done in a vacuum. Otherwise, it’s experimentally worthless. What’s bothering me is that, so far as I know, none of the tests has been done in a vacuum.
In air, there are all sorts of ways to get thrust from electrical charges. Look for “lifters” or “electrostatic lifters” for just one example.
Extraordinary claims require extraordinary proof, and IMHO, the “EM Drive” has come nowhere near offering any such proof.
I’d be utterly delighted to be wrong.
Is a vacuum chamber enough an experimental control? Wouldn’t you also have to put the apparatus in a Faraday cage or some sort of structure to prevent magnetic or electrostatic interaction?
I mean, you can produce static “thrust” by having a powerful enough magnet in a vacuum pulling on a sheet of steel somewhere off to the side?
You can check out the link to the paper they published in my previous response to ArizonaCJ. However note the vacuum chamber they are using is a solid steel cylinder with RF gaskets used where the RF feed lines go into it. I would think that with the chamber sealed and under vacuum it would make for a very effective Faraday cage. (See the photos in the paper along with a very good exposition on their torsion balance used to measure thrust).
What intrigues me is that the thrust curves as shown in the paper don’t look thermal in nature to me, as I would have expected to see gentle saw tooths as the device heated up and cooled down. Not the abrupt square waves we see here. But granted these are minuscule forces being measured.
Me too. There is AFAIK so far only the one paper here:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140009930.pdf
which tested mainly the Cannae drive and one implementation of the Shawyer EmDrive (they call it the conical Q-drive), again not under vacuum conditions. Therefore I’d have to label these experiments at best inconclusive.
However there was an enigmatic post by Paul March to the NasaSpaceFlight forum on this topic back in February that said the experiment *had* been re-performed in vacuum and with *positive* results. See this link:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608
But so far I haven’t seen any more papers about it forthcoming. Paul says in this posting that they need to get the thrust force up to 100uN in order to take the experiment to Glenn, because their thrust stand can only measure down to 50uN and so far they claim only to see in the 50uN and 16uN (with a failing RF power amp). Running RF power amplifiers in a hard vacuum is a difficult proposition they are struggling with. Until they can overcome this obstacle, Paul says there isn’t any point going to Glenn. But they hoped to have a better experiment up and running in “a few months”. Well we’re technically there, but still haven’t heard anything. But I could just be behind the news curve here.
“EmDrive == Experimental Error?”
I’m not convinced otherwise. Once you’ve eliminated ion wind and buoyancy artifacts, the magnitude of measured effect is so minute the EM forces through the power feed line might produce that much effect.
The paper I previously linked to mentions that. Claims there is a null force of 9.6 uN due to 5.6A of DC current in power cable to RF amp. See caption to Figure 20 on page 16.
Yes, almost certainly experimental error, considering that a working reactionless thruster is a perpetual motion machine of the first kind.
Even so I would like to see the experimental falsification of the proposition. Either a thorough error analysis and firm refutation or a solid claim of a positive result. Good experiments, esp. those that falsify a hypothesis, are worth their weight in gold. Bad experiments or incomplete work is worthless.
I agree. I haven’t seen it expressed in a chart like that before, and it very graphically underscores how important it is to do partial gravity research if we’re serious about going anywhere in the solar system.
And not just for humans. We need to know how plants react, and there are a whole lot of plants to test. We also need to test small edible animals (chickens, rabbits, fish?) unless we eventually want to go vegan.
If it turns out 0.4 G is great for humans, we could look at modifying plants to have less stem and more seed or fruit.
If we rely on NASA to perform those experiments, we’ll be producing meat on a 3D printer well before we know whether animals can survive in space.
But I have to disagree with the basic premise. The only reason we can’t go to Mars right now is that it’s too darn expensive. If we could put stuff on Mars for $10 a pound, there’d already be multiple colonies there. Yes, most of those colonies would fail, and most of the colonists would die before they learned how to live in a new environment. But that’s what happens when you open a new frontier.
Wanting to be sure you’re safe before you go is a recipe for never going. There’ll always be one more experiment to try first.
we could look at modifying plants to have less stem and more seed or fruit
Another reason we can’t go to Mars: GMO Opponents.
Yea, I think the charts did a good job in that respect. The NASA folks should pick up on it!
Hopefully someone at SpaceX reads The Space Review. Egad, has it been more than 3 years?
http://www.thespacereview.com/article/2089/1
If NASA was serious about Mars, they’d have a big centrifuge in orbit and/or be working madly with DoD on a reactor for high-power SEP. NASA wants to spend $100 billion or more for CxP2.0 to get astros to Mars 50 years from now. Hearing “Houston, we’ve fallen and we can’t get up” because of muscle and bone atrophy won’t be as funny as it sounds.
Well, I agree we need fuel depots.
I don’t agree that we need a large lunar exploration effort, rather what we need is to determine whether there is commercially minable
lunar water.
So NASA should develop fuel depots so that fuel depots are operational. Which means that if one wanted to send a robotic mission to Mars or the Moon, an option the robotic mission could have is to first dock with depot and get rocket fuel for the mission.
So at moment it’s experimental and not an available option.
NASA getting depot operational is not about lower costs, lower costs is something one gets from a competitive market.
Nobody can mine the Moon for lunar water, because the Moon hasn’t been explored to determine if and where there are minable lunar water deposits.
One should not have a base on the Moon, unless there is minable lunar water.
If NASA explores the Moon and determines that there is not minable lunar water, then before using the Moon we need to find minable water somewhere else in space. Or in the short term, forget about the Moon.
There are other possible place to mine water in space but we have not found them yet. There could minable water on Mars moons or other large rocks which don’t require much delta-v.
Since we have detected and measured water on the Moon, whether there is minable lunar, largely about unforeseeable
problems, or more likely the details of when and how it could be done. But it’s not about NASA mining lunar water. Perhaps after NASA explores the Moon to determine if and where there is minable lunar water, at some later point in time, NASA might mine lunar water [and it would be a mistake to do this] but before anyone can mine lunar water the moon needs to to explored first. No says there is gold in Oregon in the mountains, lets spend billion of dollars before we take a look at it. Just maybe core sample could be useful.
So NASA works towards getting an operational depot in LEO, then it uses the depot to send robotic mission to the Moon, then it send crew to the Moon [using depots] and explore Moon.
What is learned about the Moon in regards the minability of lunar water could be included in where and what NASA explores next, though the general plan is explore the Moon, then explore Mars- which might include Mars’ moons.
The purpose of exploring Mars is to determine if and where on Mars there could human settlements. So that largely going to be about find accessible water on the Mars. Which probably should be liquid water which can drawn from wells. For human settlements one will need a lot of water. For Mars exploration, one need some water [hundreds to thousands of tons- whereas human settlements, it’s millions to billions of tons which is accessible at low cost per ton].
By the time NASA begins to explore Mars, NASA should get to point of buying it’s rocket fuel from a depot. So companies invest in building depots and delivering rocket fuel which NASA could buy for it’s operational needs of exploring Mars.
NASA should focus on sending crew to Mars within 3 month travel time, and use a lot rocket fuel in order to get to Mars this quickly, and NASA should stage to go to Mars from High earth orbits rather than LEO. So for instance at EML-1 or 2.
So NASA would buy rocket fuel at EML-1, and at Mars L-1 or 2, and at Mars low orbit. And NASA doesn’t operate the depots or delivers rocket payloads to them, rather it buys the rocket fuel it needs when it needs it.
And NASA doing this will help “make” lunar water minable- to some extent.
I suspect that everyone who (1) wasn’t at DragonCon and (2) cares about this slide presentation is probably reading Rand’s blog. So I’ll just announce it here. After more video file manipulation than should have been necessary, I’ve uploaded my slides to YouTube with the audio track that I recorded at the con. If you have an hour to spare, feel free to follow along and listen at the link below:
Why We Can’t Go to Mars