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#226 2016-10-20 17:39:06

RobS
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From: South Bend, IN
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Re: Musk's plans for Mars

My guess--and it is a guess, for what it is worth--is that all the ancient flood deposits and little channels, and maybe the recurrent lineae, tell us that Mars has a water table, now frozen solid. At the poles, it is at the surface; at the equator it may be as much as 100 meters down. Some fresh craters show signs of water leaking into them at a certain depth, and that reveals the depth to the ice table at those locations. If the regolith is 25% porosity and all that pore space is ice, that's a lot of ice. A deep drill, a few explosives set off at the bottom to crack the bedrock (lamp black and liquid oxygen works pretty well, I understand), and a solar heating system to pump heated and compressed Martian air down the shaft should return cooled air that is saturated with water vapor. As the warmth works its way outward, it will produce a bubble of liquid water which will flow into the hole at the bottom of the shaft. That strikes me as the simplest way to get water out of the ground. But developing and testing the system is necessary, and a lot of that has to be done on Mars.

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#227 2016-10-20 18:23:03

RobertDyck
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Re: Musk's plans for Mars

GW Johnson wrote:

What you need is around a 1000 feet or more of ice vertically,  that is is more ice-than-regolith,  so that you have the room to drill down from one wellhead,  turn and slant across the deposit horizontally.
...
If you do find a place like that (massive mostly-ice 0.5 km or more thick),  it becomes very attractive to produce huge excesses of water there,  and then truck it,  or (later on) send it by pipeline,  anywhere else you want on Mars.

Whoa! That's asking a lot. The frozen pack ice is attractive because it's so close to the equator, flat smooth ground so safe to land, low altitude so plenty of atmosphere overhead for radiation shielding. The European Space Agency studied it, and found "sploosh" craters. That is the rim clearly shows a splash of slush. That means it was ice, or high concentration of ice, when the meteorite struck. These craters provide a look down into the mass, basically an impactor showing a pre-dug whole deep within the deposit. ESA concluded it's an average of 45m deep (147.6 feet). It covers an area greater than all the great lakes combined, providing total volume of ice greater than all the water of the great lakes combined. That's a lot. And that doesn't have to be trucked. That can be harvested and utilized locally.

The question is whether it's solid ice, or thin layers of ice interspersed with soil, mud, or solidified lava. Based on "sploosh" craters, I believe it has at least enough ice to be harvested with steam.

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#228 2016-10-21 12:23:09

GW Johnson
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From: McGregor, Texas USA
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Re: Musk's plans for Mars

Hadn't thought about it,  because it doesn't happen here,  but one could drill straight horizontally from the floor of one of those craters into the buried pack ice.  That eliminates the large vertical dimension needed to turn a drill string. 

The "sploosh" description lends some confidence to the notion of more-ice-than-regolith in whatever these "buried pack ice" things are.  Otherwise,  flat ground,  low elevations,  and near-equatorial location sounds good.  Definitely worth landing a team equipped with the necessary horizontal drilling equipment to find out just how "good" the resource really is. 

That destination should make at least some sense to Musk and his people.  He will need a big source of water to make LOX-LCH4 the way he published recently in Guadalajara. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#229 2016-10-21 18:32:37

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Musk's plans for Mars

I've always advocated finding a glacier or frozen lake and drilling into it after softening with microwave beam - then just remove the chunks of ice.

There appear to be good candidates for both glaciers and frozen lakes.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#230 2016-10-21 20:01:35

SpaceNut
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From: New Hampshire
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Posts: 29,428

Re: Musk's plans for Mars

One of the things that we need is the ability to get crew past orbit to the transistion of going to a distant place whether this be the moon or mars but we need to do this safely.
If this requires sub assembly of what we go in from orbit, so be it.
This should be what Nasa is building but instead congress chose to build the monster SLS which has been eating its budget for years....In doing so its needed a COT delivery system to save money out of going to the ISS first cargo and then crew. Nasa needs to work that next transit station from orbit assembly next with those that are waiting in the wings for contracts to make this COT habitat area work for what we need in order to go beyond earth orbit. This station is then affixed with the earth depature stages and such to allow for it to go from place to place with first the moon and then to follow once we have a capable lander for mars and surface habitats to allow mn to get that foothold to which we need to be able to use a cots system for mars.....

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#231 2016-10-21 20:14:51

RobS
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Re: Musk's plans for Mars

Here's Robert Zubrin's critique of Musk's plan. He suggests making it smaller, starting smaller, and converting the propulsion module of the ITS into a detachable stage for trans-Mars injection only. Landing would be accomplished by a much smaller stage and the ITS would then become Martian housing and would not return to earth.

http://www.thenewatlantis.com/publicati … izing-mars

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#232 2016-10-21 22:49:56

kbd512
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Re: Musk's plans for Mars

Dr. Z has some of the same criticisms I have of ITS.  However, I'll note where Dr. Z and KBD differ.

1. The extremely large size is a requirement for delivery of extremely massive payloads to the surface of Mars.  SLS is an exploration class rocket.  ITS is an industrialization class rocket.  There's a difference.  I think Mr. Musk is deluding himself if he thinks NASA will let him light that thing off on 39A.  ITS should be fueled and launched from a steel barge built like a battleship in the middle of the Atlantic, well away from anything as delicate as a typical launch pad.

2. Production of methalox for reusable landers that stay on Mars requires far less power and mass than would be required to refuel that enormous spaceship.  The most compelling reason to keep both parts of the rocket in or near LEO is immediate recovery of the upper stage.

3. Dr Z. can offer all the praise and caution he wants, but NASA still needs to foot the bill for development of the ISPP plant.  NASA needs that technology every bit as much as SpaceX does.

4. Reusability is important, but match the propulsion technology to the Isp requirement.  An all-chemical propulsion solution is impractical for what Mr. Musk wants to use it for.  A LANTR is the most practical near-term propulsion technology for transport of humans to Mars.  If the fusion rocket that MSNW is working on encounters no major technological hurdles, as has been the case thus far, then in about another ten years or so the possibility of swiftly transporting humans to Mars and then swiftly returning the orbital transfer stage to Earth becomes practical.

5. Like Dr. Z said, skip the refueling.  Deliver cargo with SEP or NEP from LEO and humans using NTR's.  Cargo flights dictate maximum delivered tonnage and crewed flights dictate maximum velocity for swift transits.

6. It doesn't matter how big or small the rocket engine is.  What matters is all the associated structural mass and propellant production mass is going back and forth between Earth and Mars.  That's grossly inefficient.  Smaller and lighter is better.  A small fleet of methalox powered landers that can deliver 50t or so to the surface is all that's required for initial colonization efforts.

7. Mars does not need giant, unshielded structures.  Mars needs buried modules that shield the occupants from GCR's.  Whereupon industrial-scale steel and concrete production is possible, the colonists can move into more spacious subterranean structures.

8. Quick trips to Mars won't be possible without fusion rockets, but as soon as fusion rockets are available, getting to Mars in 30 days is highly desirable because it dramatically reduces consumables requirements.  If NASA wants to spend a few billion on new rocket technology, this technology is the clear winner, not SLS.

9. Supersonic retro-propulsion is a requirement to deliver 50t payloads, period.

ITS Improvements

Don't improve ITS, farm out the infrastructure ITS requires to people with the know-how.  Individually develop the functional parts of the plan in a private-public partnership.

NASA provides training for colonists - NASA trains astronauts

NASA EagleWorks and Boeing develop the cargo delivery propulsion solution - Dr. White should spearhead this effort

NASA GRC develops the propellant plant - Dr. Zubrin should spearhead this effort

MIT and ILC Dover develop the MCP suits - Dr. Newman should spearhead this effort

MSNW develops the fusion rocket - MSNW is already doing this

Boeing and Blue Origin develop the reusable lander - Boeing is already developing a lander and it may as well be reusable

Boeing develops the quad copter for aerial transport - Boeing makes Ospreys and advanced composites

Newport News / Northrop-Grumman develops the barge - A US Navy shipbuilder can easily build an armored barge

Lockheed-Martin develops the 100MWe fusion power plant ultimately required for colonization - Lockheed-Martin is already doing this

SpaceX develop the ITS first stage - SpaceX is already doing this

SpaceX and Sierra Nevada develop the ITS second stage - Sierra Nevada has more experience with lifting bodies than SpaceX

Orbital ATK develops micro GPS and communications satellites and StratoLaunch deploys the constellation - Orbital ATK already does this for the US Air Force and StratoLaunch needs to do something useful for the space program

Mr. Musk has the vision, but it'll take every major player to make his vision a reality.  I am convinced that we still have the right stuff and that we can make this happen.

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#233 2016-10-22 07:34:16

RobS
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Re: Musk's plans for Mars

I'm not convinced, kbd. The opposition to nuclear rockets is emotional and therefore political, and a Mars trip is not a simple scientific matter; it is also emotional and political. The big question is whether Musk really can get launch costs to low Earth orbit down to $25,000 per tonne. When you look at his numbers, that appears to be his assumption. Why spend billions on nuclear rockets if you can get propellant to LEO that cheaply? New Horizons, on its trip to Pluto, passed the orbit of Mars in about 30 days, so it is possible with chemical propellants to get things to Mars that fast. If chemical propellant is "cheap" why bother with anything else?

The real assumption of Musk's to question is whether he really can reduce the cost of launch that much. If so, ion engines are a waste of money to develop. Zubrin's suggestion to leave the ITS on Mars also violates that assumption because it costs a hundred million or so to build each ITS. Why house 100 people on Mars for a million bucks each? Musk wants to get people there for $200,000 each! They need to build underground housing there more cheaply than living in vehicles designed for deep space conditions.

You are right, if Musk's assumption that he can get launch costs down to $25,000 per tonne--$12 per pound!--is incorrect, then all these other options become reasonable alternatives. You have to give Musk credit for chutzbah, for daring.

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#234 2016-10-22 08:06:35

SpaceNut
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Re: Musk's plans for Mars

The "Musk wants to get people there for $200,000 each!" is a problem in that it takes no consideration for how much a rocket can lift to needs per person in tonnage and by doing so this lowers the number of people per launch.

Then there is this total "The big question is whether Musk really can get launch costs to low Earth orbit down to $25,000 per tonne." which then needs number for how many tons are needed per person for survival that make the price out of reach for the customer base that can afford to pay.

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#235 2016-10-22 08:10:26

Antius
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From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Musk's plans for Mars

RobS wrote:

I'm not convinced, kbd. The opposition to nuclear rockets is emotional and therefore political, and a Mars trip is not a simple scientific matter; it is also emotional and political. The big question is whether Musk really can get launch costs to low Earth orbit down to $25,000 per tonne. When you look at his numbers, that appears to be his assumption. Why spend billions on nuclear rockets if you can get propellant to LEO that cheaply? New Horizons, on its trip to Pluto, passed the orbit of Mars in about 30 days, so it is possible with chemical propellants to get things to Mars that fast. If chemical propellant is "cheap" why bother with anything else?

The real assumption of Musk's to question is whether he really can reduce the cost of launch that much. If so, ion engines are a waste of money to develop. Zubrin's suggestion to leave the ITS on Mars also violates that assumption because it costs a hundred million or so to build each ITS. Why house 100 people on Mars for a million bucks each? Musk wants to get people there for $200,000 each! They need to build underground housing there more cheaply than living in vehicles designed for deep space conditions.

You are right, if Musk's assumption that he can get launch costs down to $25,000 per tonne--$12 per pound!--is incorrect, then all these other options become reasonable alternatives. You have to give Musk credit for chutzbah, for daring.

$25/kg is about 10 times the cost of fuel for a LOX/Kerosene launcher with a mass ratio of 20.  Musk is counting on airliner economics becoming applicable to his vehicles if launch volumes get high enough.  That would only work if the vehicles need virtually no maintenance between flights and their airframes have lifespans equivalent to those of jet planes.  Based on your collective knowledge of rocket vehicles, is that ever likely to be achievable, for vehicles that have to withstand the stresses of takeoff and reentry?  Can liquid fuelled rocket engines be produced that start and stop multiple times with similar maintenance burdens to high bypass turbofan engines?  Is it realistic to expect to be able to use heat shields that survive dozens of reentries without replacement, or at most, some minor touching up between flights?  Can we realistically produce rocket airframes that go through the stresses of achieving orbit and reentering, a thousand times without replacement?

If these things can really be done, then Musk's assumption on ultimate price may be achievable, especially if there are multiple vendors providing orbital injection services in competition.  Under that scenario, Musk's company would become something like Boeing or Airbus.

Last edited by Antius (2016-10-22 08:18:04)

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#236 2016-10-22 08:52:56

RobS
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Re: Musk's plans for Mars

Now, you are asking the right questions, Antius! Someone needs to go find Musk's PowerPoint. It states the manufacturing cost of each vehicle, the number of reuses, and the cost of maintenance per launch. He provides those data. If I recall, the first stage is to be reused 1,000 times. Musk does cost it all out. But whether we can usefully critique his numbers is questionable because his data is based on real engineering experience by his team. We don't have access to that.

The other day, somewhere, I saw an estimate that each Falcon 9 first stage can be reused 10 times. That seems to be based on taking the stage that "came in hot" and therefore suffered max damage. They have already refueled it 3 or 4 times and fired its engines through a full launch cycle. They probably will have to do a lot of tweaking of the existing design to get to 10. But as the tweak, they will probably figure out how to get the reuse to 20, then to 30, etc.

The ITS system will need to go through a similar iterative process because the Falcon 9 experience will not be completely applicable. The ITS will use carbon fiber, not lithium-aluminum, for example. No one knows what happens to carbon fiber after 10 or 100 cryogenic cycles. No one knew what happened to overwrapped helium bottles in superchilled liquid oxygen either, and we found that out the hard way.

To respond to Spacenut's comment: I think Musk is thinking that the Mars colony will be built to be as self sufficient as possible. Let us say the first 1,000 people require 10,000 tonnes of refining and manufacturing equipment. With that equipment they can produce all sorts of stuff using plastic and metal powders and 3-d printers and other manufacturing techniques. Those thousand people will do some science, but the geologists will probably be focused on natural resource location, for example. The next ten thousand people might need another tonne of equipment per person each; now we have 20,000 tonnes of equipment. But after that, the immigrants can buy the stuff they need on Mars and it will be made on Mars. Maybe imports at that point are down to 100 kg per person.

You can't send 1 million people all at once. You start with 100 and hundreds of tonnes of equipment, then send a few hundred, then a thousand, etc. In my Mars novel I aimed at an expansion of 30% each 26-month cycle. That seemed manageable because you can plan fairly well in that time frame. Doubling every 26 months could get you in trouble very fast because a mistake in one cycle impinges the next one severely and the one after that even more severely.

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#237 2016-10-22 10:05:42

SpaceNut
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Posts: 29,428

Re: Musk's plans for Mars

I see that the all or nothing approach for launch is still being taken with the ITS rocket, which makes for a mass of the ship a problem for the launch site as an engine failure on the pad very damaging and with the engine count so high its definetly an issue.

A take what you need for support of life on that leg of the trip makes more sense with a seperate return cargo craft sent seperately. Granted this does cause duplication of launch to mars but it reduces the size of the rocket for crew launch.

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#238 2016-10-22 11:14:46

GW Johnson
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Re: Musk's plans for Mars

Who is MSNW (too many undefined acronyms flung around too freely) and what is this "fusion rocket" they are working on?  More importantly,  why have I never, ever heard of this before? 

Further,  why should I believe that such a thing has any real near-term possibilities,  when the record of magnetic bottle fusion and similar giant physics experiments has been pretty dismal for over 6 decades now?

As for Musk vs Zubrin,  what I see (once again) is the effects of different starting assumptions. 

Zubrin is fixated on the same stages,  capsules,  and one-way habs that he has championed for years.  Musk is thinking along entirely different lines:  trying to build the interplanetary equivalent of a big ocean-going container ship that you use for all jobs,  whether it's an exact fit or not. 

Those are two completely-different startpoints.  It should be no surprise to anyone that the end results look entirely different.

There's more than one way to do this job,  there always has been.  Neither man is wrong,  and neither man is entirely right.  My own update of the 1950's plan is yet another way that would work.  I share the large lander idea with Musk,  but that's coincidence.  My lander is my surface hab,  but unlike Zubrin I fly it back up (although I leave it at Mars),  because I intend to land at more than one site during the mission (also unlike Zubrin,  and unlike Musk). 

See how different starting assumptions lead you to different end results?  Your starting assumptions are things you make,  they are not inherently imposed by the objective (putting men on Mars).  They do need to be consistent with all knowable constraints (like delta-vees,  Isp's,  entry ballistics,  microgravity diseases,  radiation exposure,  and all sorts of life support requirements). 

What you have to beware of is bad starting assumptions.  But also that there is no one set of "right" assumptions. 

When I worked in defense weapons,  I started having amazing successes once I learned to question the assumptions I was told to make by middle and upper management.  What I found was that 90-99% of the time,  they were not just wrong,  they were egregiously,  incompetently inappropriate. 

So I have questioned all starting assumptions ever since,  and that has never steered me wrong.  Makes me unpopular,  perhaps,  but not wrong. 

The nonsense about a million-man colony supported by immigrants 100 at a time is confusing the issue,  that's 50-100 (or more) years in the future.  You send tons of stuff and very small crews for the very first decades.  You also rotate crews every trip,  as there won't be a decent place to live long-term,  for a long time yet. 

You don't even really know that where you started landing is ultimately where you want your colony anyway.  You cannot know until you try.  That's just one of the ugly little facts of life. 

GW

Last edited by GW Johnson (2016-10-22 11:17:47)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#239 2016-10-22 16:48:34

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Musk's plans for Mars

It's interesting you mention the 1950s plans because I feel Musk is almost going back in time for his inspiration.

Of course I am rooting for Musk in the sense I root for anyone ambitious to get to Mars but his way is not mine. smile

Let's get the problem right conceptually. I think first off we need to set the telescope the right way. As far as I can see Mars is just one huge bundle of fantastically useful resources. That should be the starting point.  On that basis, given the difficulties of launch, and EDL we should be looking to minimise the transit load or to keep transit loads within a range that can be achieved without huge innovation.

So my view has always been: break down the mission into bite size chunks (i.e. lots of pre-landings and a relatively small human lander mission). 




GW Johnson wrote:

Who is MSNW (too many undefined acronyms flung around too freely) and what is this "fusion rocket" they are working on?  More importantly,  why have I never, ever heard of this before? 

Further,  why should I believe that such a thing has any real near-term possibilities,  when the record of magnetic bottle fusion and similar giant physics experiments has been pretty dismal for over 6 decades now?

As for Musk vs Zubrin,  what I see (once again) is the effects of different starting assumptions. 

Zubrin is fixated on the same stages,  capsules,  and one-way habs that he has championed for years.  Musk is thinking along entirely different lines:  trying to build the interplanetary equivalent of a big ocean-going container ship that you use for all jobs,  whether it's an exact fit or not. 

Those are two completely-different startpoints.  It should be no surprise to anyone that the end results look entirely different.

There's more than one way to do this job,  there always has been.  Neither man is wrong,  and neither man is entirely right.  My own update of the 1950's plan is yet another way that would work.  I share the large lander idea with Musk,  but that's coincidence.  My lander is my surface hab,  but unlike Zubrin I fly it back up (although I leave it at Mars),  because I intend to land at more than one site during the mission (also unlike Zubrin,  and unlike Musk). 

See how different starting assumptions lead you to different end results?  Your starting assumptions are things you make,  they are not inherently imposed by the objective (putting men on Mars).  They do need to be consistent with all knowable constraints (like delta-vees,  Isp's,  entry ballistics,  microgravity diseases,  radiation exposure,  and all sorts of life support requirements). 

What you have to beware of is bad starting assumptions.  But also that there is no one set of "right" assumptions. 

When I worked in defense weapons,  I started having amazing successes once I learned to question the assumptions I was told to make by middle and upper management.  What I found was that 90-99% of the time,  they were not just wrong,  they were egregiously,  incompetently inappropriate. 

So I have questioned all starting assumptions ever since,  and that has never steered me wrong.  Makes me unpopular,  perhaps,  but not wrong. 

The nonsense about a million-man colony supported by immigrants 100 at a time is confusing the issue,  that's 50-100 (or more) years in the future.  You send tons of stuff and very small crews for the very first decades.  You also rotate crews every trip,  as there won't be a decent place to live long-term,  for a long time yet. 

You don't even really know that where you started landing is ultimately where you want your colony anyway.  You cannot know until you try.  That's just one of the ugly little facts of life. 

GW


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#240 2016-10-22 18:04:50

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,924
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Re: Musk's plans for Mars

GW Johnson wrote:

Who is MSNW (too many undefined acronyms flung around too freely) and what is this "fusion rocket" they are working on?  More importantly,  why have I never, ever heard of this before?

I haven't heard of them either. However, a quick Google reveals...
Space Propulsion - MSNW LLC

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#241 2016-10-23 02:29:55

kbd512
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Registered: 2015-01-02
Posts: 7,812

Re: Musk's plans for Mars

RobS wrote:

I'm not convinced, kbd. The opposition to nuclear rockets is emotional and therefore political, and a Mars trip is not a simple scientific matter; it is also emotional and political. The big question is whether Musk really can get launch costs to low Earth orbit down to $25,000 per tonne. When you look at his numbers, that appears to be his assumption. Why spend billions on nuclear rockets if you can get propellant to LEO that cheaply? New Horizons, on its trip to Pluto, passed the orbit of Mars in about 30 days, so it is possible with chemical propellants to get things to Mars that fast. If chemical propellant is "cheap" why bother with anything else?

The real assumption of Musk's to question is whether he really can reduce the cost of launch that much. If so, ion engines are a waste of money to develop. Zubrin's suggestion to leave the ITS on Mars also violates that assumption because it costs a hundred million or so to build each ITS. Why house 100 people on Mars for a million bucks each? Musk wants to get people there for $200,000 each! They need to build underground housing there more cheaply than living in vehicles designed for deep space conditions.

You are right, if Musk's assumption that he can get launch costs down to $25,000 per tonne--$12 per pound!--is incorrect, then all these other options become reasonable alternatives. You have to give Musk credit for chutzbah, for daring.

I'll save everyone, including Mr. Musk, some time and effort.  A cost of $12 per pound is not reasonable.  Sending a vehicle with a higher inert mass than the Space Shuttle to the surface of Mars and then back to the surface of Earth two years later is also unreasonable.  The ITS upper stage (Space Shuttle II) is essentially what the STS upper stage (Space Shuttle I) was supposed to be, but wasn't.  That said, STS and ITS are guaranteed to cost more and require more refurbishment than anyone originally thought.

Instead of forcing vehicles to service so many divergent requirements, we should make it do one thing really well, namely delivering a payload to orbit with full reusability.  ITS should deliver humans or cargo to orbit in a complete package that's ready to ship to Mars, de-orbit, and land vertically on a landing pad at KSC.  That's all it should do because that's all it really needs to do.  If it can do that on a routine basis, then it's already done more than any other spacecraft ever has.

Only nuclear fusion rockets can substantially reduce travel time, keeping the colonists sane and simultaneously lowering the mass of the overall solution to something sane.  Thus far, no major design challenges have been encountered with the development of the fusion rocket.  There's a world of difference between trying to contain a fusion reaction for any length of time and intentionally allowing the superheated plasma to escape from the reactor.

If we get the colonists to Mars in 30 days, which is what fusion rockets allow us to do, then the mass of the consumables stays within the limitations of something we can reasonably send to and from Mars on a regular basis.  I just don't see this working, absent leap-ahead in-space propulsion technology.

If the so-called EMDrive functions properly, then the efficiency of electric propulsion dramatically improves overnight and cargo deliveries only require fancy solar panels and fancy microwave ovens.  LENR's can potentially remove the requirement for fancy solar panels and then the primary cost of the cargo is the cost of delivering it to orbit.  The reusable landers permanently based on Mars would retrieve cargo from orbit.  The cargo delivery propulsion systems only have to last long enough to get to Mars and remain in orbit until retrieval is possible.  The ultimate goal is to retire expensive solar panels and reaction mass engines (chemical, fission, and fusion rockets).

The separation of human and cargo delivery solutions services divergent requirements of either minimizing travel time or minimizing the cost of delivered cargo.  A single inexpensive solution to deliver both is desirable, but not presently practical.  New thinking at Boeing and NASA is that we can ballistically capture at Mars to deliver regular cargo shipments.

The more often we fly ITS, the cheaper it gets.  We can't do that with Mr. Musk's all-chemical propulsion solution and the infrastructure to use it as intended does not exist.

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#242 2016-10-23 06:34:06

RGClark
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From: Philadelphia, PA
Registered: 2006-07-05
Posts: 763
Website

Re: Musk's plans for Mars

GW Johnson wrote:

...

What you have to beware of is bad starting assumptions.  But also that there is no one set of "right" assumptions. 
When I worked in defense weapons,  I started having amazing successes once I learned to question the assumptions I was told to make by middle and upper management.  What I found was that 90-99% of the time,  they were not just wrong,  they were egregiously,  incompetently inappropriate. 
So I have questioned all starting assumptions ever since,  and that has never steered me wrong.  Makes me unpopular,  perhaps,  but not wrong. 
...
GW

Thanks for that. It reminds me of something I wrote on sci.space.shuttle after the space shuttle Columbia accident. I ended the post with the question: Are lower-level employees always smarter than top-level management?

=====================================================
From: rgrego...@yahoo.com (Robert Clark)
Newsgroups: sci.space.shuttle,sci.space.history,sci.space.policy,sci.astro
Subject: Re: Washington Post: High level NASA request for Columbia imaging
Date: 15 Mar 2003 02:42:03 -0800
Organization: http://groups.google.com/
Lines: 76
Message-ID: <832ea96d.0303150242.669d5239@posting.google.com>


AbelM...@webtv.net wrote in message news:<23378-3E7...@storefull-2173.public.lawson.webtv.net>...
> I feel vindicated now, because this is exactly what I posted,
> immediately after the Shuttle blew up. You wouldn't believe the names
> people called me, everything from "liberal idiot", to "unpatriotic" and
> so on. I had never been called so many names by so many people.
> I was certain then that it is this corporate culture of intimidation
> that Bush has fostered, it is this same culture of intimidation and of
> looking down on subordinates that also led to 9/11.  Four months before
> 9/11, an FBI Agent, Coleen Rowley warned the FBI that Arab terrorists
> were learning to fly planes but not learning how to land them, she found
> this extremely suspicious, but the FBI heads told her to shut up.  So
> she went to the CIA after that, out of sheer frustration, and she was
> reprimanded, her job was threatened after she did that. 4 months later,
> 9/11 happened. 
>
>...

Shuttle Team Sought Satellite Assessment of Liftoff Damage
"He said Lambert Austin, an engineer at Johnson Space Center in
Houston, had asked Ron D. Dittemore, the shuttle program manager, in a
group meeting to obtain satellite images to help gauge the damage. Mr.
Dittemore turned down the request, even though Mr. Austin was also
speaking for several other engineers, the official said.
"Mr. Austin and his colleagues were disappointed, the official said,
especially because they believed Mr. Dittemore did not have the
technical knowledge of imagery to determine whether the images would
have been helpful.'
http://www.nytimes.com/2003/03/13/natio … 3SHUT.html


About the Coleen Rowley 9/11 memo:

How the FBI Blew the Case
The inside story of the FBI whistle-blower who accuses her bosses of
ignoring warnings of 9/11. A reading of her entire memo suggests a
bracing blueprint for change.
"Rowley and her colleagues continued to plead their case. Her memo
rails against but doesn't name a handful of midlevel officials who
"almost inexplicably" blocked "Minneapolis' by now desperate efforts
to obtain a FASA search warrant ... HQ personnel brought up almost
ridiculous questions in their apparent efforts to undermine the
probable cause." One supervisor complained that there might be plenty
of men named Zacarias Moussaoui in France; how did the agents know
this was the same man? (The agents checked the Paris phone books and
found but one Moussaoui.) At another point the field office tried to
bypass their bosses altogether and alert the CIA's Counterterrorism
Center; Rowley says FBI officials chastised the agents for going
behind their backs."
http://www.time.com/time/nation/article … 94,00.html

Copy of the Coleen Rowley memo here:

Coleen Rowley's Memo to FBI Director Robert Mueller
An edited version of the agent's 13-page letter
"5) The fact is that key FBIHQ personnel whose job it was to assist
and coordinate with field division agents on terrorism investigations
and the obtaining and use of FISA searches (and who theoretically were
privy to many more sources of intelligence information than field
division agents), continued to, almost inexplicably,5 throw up
roadblocks and undermine Minneapolis' by-now desperate efforts to
obtain a FISA search warrant, long after the French intelligence
service provided its information and probable cause became clear. HQ
personnel brought up almost ridiculous questions in their apparent
efforts to undermine the probable cause.6 In all of their
conversations and correspondence, HQ personnel never disclosed to the
Minneapolis agents that the Phoenix Division had, only approximately
three weeks earlier, warned of Al Qaeda operatives in flight schools
seeking flight training for terrorist purposes!"
http://www.time.com/time/nation/article … 97,00.html


   Are lower-level employees always smarter than top-level management?

===================================================


         Bob Clark


Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):

      “Anything worth doing is worth doing for a billion dollars.”

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#243 2016-10-23 13:30:56

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,812

Re: Musk's plans for Mars

MSNW LLC is the company developing the fusion rocket for NASA, GW.  MSNW, like SpaceX, is the little company that could.  They've stayed pretty much within budget, their budget is a tiny fraction of what NASA allocates for advanced space propulsion research, and they've been busy producing results for years now.  NASA believes this technology will be flight tested, given the present rate of funding for this project, in the mid 2020's, thus the early 2030's exploration missions.

This is from 2012, but explains how it works:

The Fusion Driven Rocket - Fall 2012 NAIC

The rocket does produce neutron radiation in operation.  However, only the D-T aboard is radioactive (beta decay).  This is no different than the Pu-238 fueled RTG's, except that Pu-238 does produce some low energy gamma.

The fusion rocket is the only rocket with the dV capability and fuel aboard to perform a direct abort and return to Earth.  That means turn around and come back immediately, not use a free return trajectory.

The magneto-plasma shells they're working on can aerocapture spacecraft without propellant or TPS.  More importantly, this technology can increase or decrease the field strength of the magnetic field to control deceleration in Mars' highly variable atmosphere.  If you screw up aerocapture with a conventional heat shield because you messed up the calculations, you get ejected into space or you become an impact crater on the surface of the planet.  From a payload mass fraction standpoint, this form of capture is highly desirable.

This website explains magneto-aerocapture fairly well:

Recent Altius Contract Wins: What Do They Mean? (Part 1 of 2)

MSNW is still trying to use NASA's approach of delivering everything required for landing on the surface of the planet using one super heavy lift vehicle like SLS.  I'm trying to figure out if the hardware to simply get there and come back can be delivered to LEO using one Falcon Heavy.  I would rather have the lander / return vehicle and surface habitat delivered to Mars at the same time aboard different rockets, rather than push the mass of everything required with a single rocket.  The multiple launch approach is not more complicated than the one launch approach because it dramatically lowers the mass and performance requirements of both the chemical rocket and fusion rocket.

For exploration purposes, which I believe needs to happen before colonization, fusion rockets and magneto-aerocapture could conceivably enable a three Falcon Heavy mission architecture that delivers all required mission hardware elements to Mars during the same window.

For colonization purposes, direct return to return to Earth in a reasonable amount of time is a distinct advantage if something unforeseen  happens in the colony that reduces its ability to support additional colonists (crops die, water treatment or power plant issues, reusable lander or propellant plant explodes, etc).

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#244 2016-10-23 20:50:51

clark
Member
Registered: 2001-09-20
Posts: 6,374

Re: Musk's plans for Mars

1,000,000 people on Mars, what exactly do they do?

And that's the easy question.

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#245 2016-10-24 02:21:53

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Musk's plans for Mars

I'm with you on this kbd - I have never been able to understand what the problem is with multiple launches and, where necessary, orbital assembly.  The great advantage is that you don't need to develop huge, innovative rockets and, also, you can pre-land equipment to the landing zone, thus ensuring you

Of course it does mean you have to be fairly confident of your ability to land everything in the same drop zone of perhaps 25 sq. kms. But there is no evidence that we don't have that ability.

Of course Musk's approach is more appropriate to his overall goal of transferring tens of thousands of people to Mars quickly. But I do have doubts about that. 

kbd512 wrote:

MSNW LLC is the company developing the fusion rocket for NASA, GW.  MSNW, like SpaceX, is the little company that could.  They've stayed pretty much within budget, their budget is a tiny fraction of what NASA allocates for advanced space propulsion research, and they've been busy producing results for years now.  NASA believes this technology will be flight tested, given the present rate of funding for this project, in the mid 2020's, thus the early 2030's exploration missions.

This is from 2012, but explains how it works:

The Fusion Driven Rocket - Fall 2012 NAIC

The rocket does produce neutron radiation in operation.  However, only the D-T aboard is radioactive (beta decay).  This is no different than the Pu-238 fueled RTG's, except that Pu-238 does produce some low energy gamma.

The fusion rocket is the only rocket with the dV capability and fuel aboard to perform a direct abort and return to Earth.  That means turn around and come back immediately, not use a free return trajectory.

The magneto-plasma shells they're working on can aerocapture spacecraft without propellant or TPS.  More importantly, this technology can increase or decrease the field strength of the magnetic field to control deceleration in Mars' highly variable atmosphere.  If you screw up aerocapture with a conventional heat shield because you messed up the calculations, you get ejected into space or you become an impact crater on the surface of the planet.  From a payload mass fraction standpoint, this form of capture is highly desirable.

This website explains magneto-aerocapture fairly well:

Recent Altius Contract Wins: What Do They Mean? (Part 1 of 2)

MSNW is still trying to use NASA's approach of delivering everything required for landing on the surface of the planet using one super heavy lift vehicle like SLS.  I'm trying to figure out if the hardware to simply get there and come back can be delivered to LEO using one Falcon Heavy.  I would rather have the lander / return vehicle and surface habitat delivered to Mars at the same time aboard different rockets, rather than push the mass of everything required with a single rocket.  The multiple launch approach is not more complicated than the one launch approach because it dramatically lowers the mass and performance requirements of both the chemical rocket and fusion rocket.

For exploration purposes, which I believe needs to happen before colonization, fusion rockets and magneto-aerocapture could conceivably enable a three Falcon Heavy mission architecture that delivers all required mission hardware elements to Mars during the same window.

For colonization purposes, direct return to return to Earth in a reasonable amount of time is a distinct advantage if something unforeseen  happens in the colony that reduces its ability to support additional colonists (crops die, water treatment or power plant issues, reusable lander or propellant plant explodes, etc).


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#246 2016-10-24 02:46:11

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Musk's plans for Mars

I have my doubts about Musk's colonisation project.  My doubts are focussed on whether there are in fact 1 million people on planet Earth with the right skills, and the right mindset to become permanent residents on Mars, never feeling the wind and sun on their faces, never again meeting family and friends they leave behind, and not being able (yet) to raise a family (because of likely foetal abnormalities in a low G environment)... and yet being highly educated people with crucial, vital skills.

That said, I don't think it's hard to imagine what 1 million people on Mars might do.

Here are some guesstimates:

50,000 - Governance and administration.

200,000 - Agriculture, food and crop processing (The colony will need about 3000 tonnes of food a day. Indoor agriculture will be quite labour intensive I think, so an average of 15 pounds of food production per agricultural worker seems about right, and of course non-food crops will also be produced) .

100,000 - industrial and commodity production (e.g. steel, plastics, furniture, utensils, plumbing items, photovoltaic panels, methane would be prominent).

5,000 - medical services and health monitoring

100,000 - life support (ensuring artificial air production and distribution, control of pathogens in air, clean water supply, heating and lighting, etc etc)

40,000 - Energy production and distribution

170,000 - Construction and building maintenance

5,000 - Mining (water ice and mineral mining)

40,000 - Retail and warehousing

100,000 - Scientific research (Mostly Earth-funded researching various aspects of Mars and the solar system).

25,000 - Recycling (the colony will need to recycle just about everything, but particular rare resources like copper)

30,000 - Transport

20,000 - Higher Education and Training

20,000 - Induction support for new arrivals

50,000 - Other








clark wrote:

1,000,000 people on Mars, what exactly do they do?

And that's the easy question.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#247 2016-10-24 06:53:59

RobS
Banned
From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
Website

Re: Musk's plans for Mars

Musk answered questions on reddit about his system on Saturday: http://www.theverge.com/2016/10/23/1337 … pacex-mars

Take a look. He talked about geodesic domes for the plants and tunnels for the industrial plant. People will feel the sun on their faces.

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#248 2016-10-24 07:39:54

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Musk's plans for Mars

7. The sending of a large habitat on a roundtrip from Earth to Mars and back. This, too, is a very bad idea, because the habitat will get to be used only one way, once every four years. If we are building a Mars base or colonizing Mars, any large habitat sent to the planet’s surface should stay there so the colonists can use it for living quarters. Going to great expense to send a habitat to Mars only to return it to Earth empty makes no sense. Mars needs houses.

The thing is, some people will want to return to Earth, so we will need  ship that can support human life on the way back to Earth. I think we can use both a reusable spaceship. And a second stage that comes in pieces for the transportation of housing structures.
news-092716c-lg.jpg
The thing is, as a historical analog, the pioneers that traveled west did not live in Contestoga wagons and railroad cars, once they got there. On the way from Earth to Mars, maybe its necessary to live in a "tin can" on the way, on Mars, people may prefer to live in a more expansive inflatable structure. Having rigid tin cans that were once part of spaceships, might not be the best living quarters, or greenhouses. The passenger module needs to house passengers, the quarters will necessarily be tight if these ships are to carry 100 people at a time. I think once people get to Mars, they might prefer to have more space and more privacy from one another rather than live in some barracks. People will want to raise their families, an a passenger/crew module might not be the best place to do so. Must did say he planned to send a lot of cargo to Mars first in preparation to ending the first humans there. I think they will not need to live in the spaceship that brought them.

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#249 2016-10-24 07:50:24

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Musk's plans for Mars

Not quite the same methinks as being out in the open air...presumably his geodesic domes will have some filtering.

RobS wrote:

Musk answered questions on reddit about his system on Saturday: http://www.theverge.com/2016/10/23/1337 … pacex-mars

Take a look. He talked about geodesic domes for the plants and tunnels for the industrial plant. People will feel the sun on their faces.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#250 2016-10-24 08:10:54

RobS
Banned
From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
Website

Re: Musk's plans for Mars

One thing that could be done: The ITS life support system could be made up of a series of modules, each designed to purify the air and water of, say, ten people. Once the ITS lands on Mars, if 100 are disembarking and 10 returning to Earth, you pull out nine of the modules and leave them on Mars. The Martian accommodations would be designed to use the same equipment, or at least with interchangeable parts.

I suspect a lot of Martian life support will work fairly differently, though. The agriculture that raises food will automatically recycle carbon dioxide, and there's an atmosphere full of the stuff, so you don't need to recycle the CO2 very efficiently. If you have access to ground ice, you don't have to recycle your water efficiently, either.

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