New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: As a reader of NewMars forum, we have opportunities for you to assist with technical discussions in several initiatives underway. NewMars needs volunteers with appropriate education, skills, talent, motivation and generosity of spirit as a highly valued member. Write to newmarsmember * gmail.com to tell us about your ability's to help contribute to NewMars and become a registered member.

#51 2008-05-14 06:50:18

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

JonClarke,

Your proposition was "Per kg they are faster cheaper and better than robots". For purely human abilities such as creativity, imagination, intuition and insight that's obviously true because robots don't currently posses those abilities, and maybe never will. For insitu sensing and analysis even MER class robots are many orders of magnitude cheaper than people. Such robots can be cheaply distributed globally around Mars. Human missions will initially be focused on small areas and will have to rely on satellites, remote networks and rovers to explore beyond their landing zone.

Nobody would seriously doubt the efficiency of satellite sensing, once upon a time people did remote sensing using aircraft. Robots in orbit are clearly far superior to humans in aircraft. The same is now true for remote and insitu sensing on Mars. Human explorers on Mars will use robots as tools for sensing and analysis both locally and remotely, their time will be too valuable for such tasks.

Sample return is not about the robot coming back, it's about returning a sample. The robot that collects the sample will probably stay on the surface.

8 hours of pure exploration work per mission day is quite efficient for a person. Consider the travel time to site, setting up camp, sleeping etc etc. And that's not including mission preparation time. ISS crews spend the majority of their waking time just maintaining their environment and their health. EVAs are particularly time consuming. Even with the expected improvements in suits, EVAs on Mars will be very inefficient compared with a geologist free to walk in the open air.

To compare the cost per kg of a MER rover (yes, about $2.5m) with the cost of crew time on ISS is ignoring the cost of the ISS which is just as vital to their mission as the system that got the MERs to the surface. Three crew weigh about 250 kg, launch costs are trivial compared to the cost of the ISS that they depend on. Add that in and they cost about $120m/kg (assuming an ISS cost of $30billion)


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#52 2008-05-15 03:18:48

JonClarke
Member
From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Problems with Humans on Mars

Your proposition was "Per kg they are faster cheaper and better than robots". For purely human abilities such as creativity, imagination, intuition and insight that's obviously true because robots don't currently posses those abilities, and maybe never will.

We agree.

For insitu sensing and analysis even MER class robots are many orders of magnitude cheaper than people.

Here you miss my point.  Such unmanned missions are cheaper only by virtue of being small and limited in number and capability.  That is fine if all you can afford is a small number of limited missions.  However because a crewed mission is vastly more capable and cheaper per kg than unmanned missions for a wide range of surface exploration activities were you to devote remotely similar resources they are much more effective.  For the same amount of money you could send approximately half the mass to Mars unmanned as you could crewed, and achieve perhaps two or three orders of magnitude less science.

Such robots can be cheaply distributed globally around Mars. Human missions will initially be focused on small areas and will have to rely on satellites, remote networks and rovers to explore beyond their landing zone.

Unmanned missions are not cheap.  The MERS cost $400 million apiece ands carry half a dozen instruments and tools.  Between then they have covered less than 20 km in nine years of exploration.  MSL costs close on two billion $ and, all being well, will carry twice the number of instruments over a similar distance.

Human missions will initially be focused on small areas and will have to rely on satellites, remote networks and rovers to explore beyond their landing zone.

I am not sure what mission architecture you have in mind but the studies I am familiar with, typical of most studies of the past 17 years, involve 1000 km of traverses in the course of a mission.

Nobody would seriously doubt the efficiency of satellite sensing, once upon a time people did remote sensing using aircraft.

No body is questioning the value of satellite remote sensing.  And airborne remote sensing is not only still used but bigger than ever.

Robots in orbit are clearly far superior to humans in aircraft

No they are not superior.  They do different things. 

Sample return is not about the robot coming back, it's about returning a sample. The robot that collects the sample will probably stay on the surface.

Part of the spacecraft remains on the surface, part of the spacecraft carries the sample back to Earth.  Just as will happen with human missions.

8 hours of pure exploration work per mission day is quite efficient for a person. Consider the travel time to site, setting up camp, sleeping etc etc. And that's not including mission preparation time. ISS crews spend the majority of their waking time just maintaining their environment and their health. EVAs are particularly time consuming.

A reasonable working day would be 8 hours sleep, 4 hours personal time, 12 hours work, 6 days a week.  Any work spent towards the continued operation of the mission is efficient, regardless of what the specific task is.

EVA time I estimate as being one day work per working week per person.  With two person EVAs and a four person crews that is two EVAs a week.  Over a 70 week surface mission that is 140 EVAs.  Assuming very conservative traverses with unpressurised rovers of 10 km per day, that means a total distance of 1400 km would be covered.  If the expedition has a pressurised rover with an endurance of 5 days and this is used for half the time, the total distance covered exceeds 2400 km.

Even with the expected improvements in suits, EVAs on Mars will be very inefficient compared with a geologist free to walk in the open air.

Inefficient compared to a geologist working on foot in mountainous terrain?  To one in the Antactic with multiple layers of cold weather gear and a heavy survival pack?  To one working underwater with a 7 mm wet suit, weight belt, sampling tools thank sink, camera gear that floats, no comunications, the mobility of an arthiritic jellyfish and a 20 minute bottom time? To a geophysicist doing a ground survey with a differential GPS unit on his back, wearing 20 kg of computers and drapping a 20 kg GPR antenna?  We also know what people could, and could not do on the Moon, and use that as a baseline.

To compare the cost per kg of a MER rover (yes, about $2.5m) with the cost of crew time on ISS is ignoring the cost of the ISS which is just as vital to their mission as the system that got the MERs to the surface. Three crew weigh about 250 kg, launch costs are trivial compared to the cost of the ISS that they depend on. Add that in and they cost about $120m/kg (assuming an ISS cost of $30billion)

You misunderstand the cost I quoted for the ISS.  The cost per kg of $212,000 is based on dividing the estimated total program costs of the ISS over its estimated operating life ($100 billion) by the estimated final completed mass (471698 kg).  It has nothing to do with the “cost of crew time” or “launch costs”.

The same calculation for Apollo, using program cost divided by mass sent to the Moon, gives $342,00 per kg.  The lower cost per kg of the ISS is what would be expected, given that almost everything to do with Apollo was developed from scratch, whereas much of the ISS used off the shelf or proven technology (even if the hardware is new).

cheers

Jon

Offline

#53 2008-05-15 03:56:45

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

Sensing and analysis is a routine, highly automated task. People add nothing of value to this task, in fact human interference would reduce its efficiency and probably its quality.

Robotic space missions are far from cheap, however standardization and reuse are reducing the cost. Mass production of components, such as nano sensors and actuators will reduce costs enormously.

Let's sort out this confusion about cost per kg. When doing any comparison it's important to compare apples with apples. ISS in LEO is not equivalent to an MER rover on Mars. The equivalent would be MER in LEO, which weighed about 10,000 kg (third stage motor, cruise stage, EDL system etc etc) not simply the 175 Kg of the rover. Recalculating on a comparative basis yields about $40,000 per kg for MER, several times cheaper than the $212,000 for the ISS.


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#54 2008-05-16 02:31:55

JonClarke
Member
From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Problems with Humans on Mars

In response to cIclops:

Sensing and analysis is a routine, highly automated task. People add nothing of value to this task, in fact human interference would reduce its efficiency and probably its quality.

This is too sweeping a generalisation.  It will depend on many factors. For example with airborne sensors, despite a lot of interest in UAVs as platforms crewed aircraft are unavoidable because of safety issues.  Also many airborne systems are so large, heavy, and require so much power it is easier to use existing crewed  aircraft that design a UAV from scratch, even were the use of UAVs legal.  Also airborne surveys are often flown at low altitude and operate in dirty, complex environments.  Much like exploring the surface of Mars.  Human operators are often required to perform in field repairs to damaged hardware.

However in general, for spaceborne remote sensing I agree with you, there is no point having people on board.  Not because people reduce efficiency and degrade quality, but because for such routine data collection there are not needed. 

But that is not the point here.  We talking about surface exploration.  There is nothing routine about exploring the surface of Mars.  There is little that can be automated.  As you said, for purely human abilities such as creativity, imagination, intuition and insight don't currently posses those abilities, and maybe never will.  But it is these skills that are need to explore Mars (or the Moon).  It is far better to have these abilities on site on Mars than 40 minutes away.  Plus the much greater array of instruments and tools that a crewed mission will have, along with orders of magnitude more power, faster operations, exploration radii and sample return capability. And the ability to explorer entire disciplines impossible for unmanned missions.

Robotic space missions are far from cheap, however standardization and reuse are reducing the cost. Mass production of components, such as nano sensors and actuators will reduce costs enormously.

Crewed missions likewise benefit from the same advances.

Let's sort out this confusion about cost per kg. When doing any comparison it's important to compare apples with apples. ISS in LEO is not equivalent to an MER rover on Mars. The equivalent would be MER in LEO, which weighed about 10,000 kg (third stage motor, cruise stage, EDL system etc etc) not simply the 175 Kg of the rover. Recalculating on a comparative basis yields about $40,000 per kg for MER, several times cheaper than the $212,000 for the ISS.

No confusion at all.  If you want to directly compare like with like, use the mass in LEO of the Mars bound spacecraft, excluding EDS propellants. The average cost per kg in LEO of orbiters, landers and rovers is $517,000 per kg, almost twice the average cost of crewed missions in LEO.

If you insist on leaving the ISS out of then equation (even though in size and complexity it is at least as challenging as Mars mission) sthen use Apollo.  With Apollo as a baseline the cost in LEO per kg of an unmanned mission is still 1.5 times that of crewed missions.

Cheers

Jon

Offline

#55 2008-05-16 06:31:55

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

No confusion at all.  If you want to directly compare like with like, use the mass in LEO of the Mars bound spacecraft, excluding EDS propellants. The average cost per kg in LEO of orbiters, landers and rovers is $517,000 per kg, almost twice the average cost of crewed missions in LEO.

If you insist on leaving the ISS out of then equation (even though in size and complexity it is at least as challenging as Mars mission) sthen use Apollo.  With Apollo as a baseline the cost in LEO per kg of an unmanned mission is still 1.5 times that of crewed missions.

Thanks for you comments Jon.

Let's finish this ISS v MER comparison instead of wandering off to another system. MER in LEO without  fuel to reach Mars is useless, it's an incomplete system. This would like excluding the solar arrays on ISS, excluding parts of a system does nothing except change the numbers. This type of analysis is pointless and so is using the metric of cost per kg to compare human and robotic systems that do entirely different jobs in completely different locations. That's why nobody uses it.


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#56 2008-05-16 17:54:23

JonClarke
Member
From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Problems with Humans on Mars

Thanks for you comments Jon.

And yours!

Let's finish this ISS v MER comparison instead of wandering off to another system. MER in LEO without  fuel to reach Mars is useless, it's an incomplete system. This would like excluding the solar arrays on ISS, excluding parts of a system does nothing except change the numbers. This type of analysis is pointless and so is using the metric of cost per kg to compare human and robotic systems that do entirely different jobs in completely different locations. That's why nobody uses it.

The problem is that people do compare costs.  Robots are "faster cheaper better".  That is why I turn it on its head, and say "people are faster cheaper better", to get people to think over the assumptions that underpin such statements.

Of course getting a meaningful way of measuring these parameters is difficult.  Faster, well you can compare rates of exploration, data gathering, better, you could use distance explored, disciplines covered, samples returned, instruments carried etc.  But cheaper?  That is difficult.  An unmanned mission will always be cheaper because its smaller.  It's like saying that we should only ever use nanosats necause they are cheaper than bus sized ones.  But which is better depends on what you want to do.

That is why I decided on trying cost per kg of payload sent to Mars.  I used published costs and masses of MRO, MGS, MO2001 for the orbiters, Phoenix for the landers, and MER and MSL for rovers.  All $$ calculated to 2006 values.  I excluded Viking, Pathfinder, and Mars Express because they were complex missions with both orbiter and lander components or, in the case of Pathfinder, a combined rover and lander.

There was a good correlation between these.  Payload in LEO came to ~500,000/kg.  Mass on the surface cost ~$1 million/kg/ and rovers $2 million/kg.  I did not work out a value in Mars orbit because, as you know, a number of these missions did not orbit.  These relationships make sense.  A lander mission sheds roughly half its mass between leaving LEO and sitting on the surface, in the form of carrier bus, propellants, shield shields, and parachutes.  So the value of what stands on the surface doubles.  Likewise a rover makes up roughly half of what actually lands, mass wise, the rest being the landing platform.  So the value doubles yet again.

I was very surprised that human missions work out cheaper by this method.  One reason might be because much of the mass is taken up with providing living volume and consumables, which are cheap compared to sophisticated radiation hardened electronics and minaturised labs.  The equipment on a human mission don't need to be minaturised to the same extent and in some cases are off the shelf items.

I certainly take your point about the propellant.  But that introduces a great deal more variabilty in mass.  Much depends on trajectories and propellants used.  The differences between solids, hypergolics, and cryogenics are quite significant.  Future missions might use ion propulsion, or even NTR.  So I excluded the propellant and engines needed to send the spacecraft to Mars (or the Moon), but not that need for Mars orbit insertion, orbital corrections, etc.  The cost of providing these is, however is included. 

There was a parallel issue with the ISS.  I did not include the mass of flghts to the ISS (Shuttles, Soyuz, Progress etc.) because they did not contribute to the permanant sructure.  But I did include their cost of because they are an essential for construction and support.

One lesson I drew from this that you were you to spend (say) 100 million on crewedmissions and 100 million of unmanned missions would would not only get a lot more bang for the buck from the crewed missions, the same amount of money would buy you less tonnes on Mars if you used only unmanned missions.  Of course any rational Mars exploration program would use both.  Unmanned missions for what they do best and people for what they do best.  And, where appropriate, in conjunction. IMHO!

There are parallels in other areas of technology.  Should a country spend is naval budget on a carrier group or missile boats?  Missile boats are faster cheaper better (and yes, that argument was very popular in the 70's and 80's).  However missile boats are more expensive per tonne than carriers and their escorts, so X $$ will buy fewer tonnes of missile boats than carrier groups.  Likewise missile boats, even in large numbers, have only a fraction the capability of a carrier group.  So which you get depends on your budget and the role you want your navy to fill.

cheers

Jon

Offline

#57 2008-05-17 04:36:20

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

Thanks again Jon.

Turning things upside down usually results in nonsense. Just because a cost/kg can be calculated doesn't mean that it has any sense. There's no meaningful correlation between cost per kg of human missions versus robotic ones unless the same types of missions are compared, and that's almost impossible. Likewise it doesn't even make much sense to compare the cost/kg of communication sats with navigation sats, and they are quite close in functionality and location. Comparing the cost/kg of different types of communication sats that have similar capabilities would make sense.

Human missions are totally different to robotic ones. Human missions are enormously expensive will continue to be so for a long time.


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#58 2008-05-17 04:50:35

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

Re: Problems with Humans on Mars

Yes "enormously expensive" - but the whole story is "enormously expensive and enormously productive".


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

Offline

#59 2008-05-17 05:03:22

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

Indeed, human spaceflight has been one of the most productive and positive activities of the 20C for stimulating technology, science, education and industry, as well as lifting the eyes and spirit of the human race. The cost is enormous, but probably less than spent on other activities such as tourism, sport, entertainment etc etc.


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#60 2008-05-17 10:36:35

Grypd
Member
From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,879

Re: Problems with Humans on Mars

This whole thread and its arquements can be put down to one arquement.

Do we as a species want to stay on this planet or do we want to spread the human race out.

Robots can be a lot more efficient than any human can and cheaper too. But humanity is still fundamentally more flexible. Any proper stratedgy will use the best bits of both man and machine.

But will we pay the cost?


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

Offline

#61 2008-05-17 10:44:19

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

As the author of this topic, allow me to restate what it's about. It's about the  problems of putting humans on Mars as discussed by Bushnell and then Rapp in their recent detailed radio interviews. Hopefully most of us here agree that we want to put humans on Mars as soon as possible.

Yes, clearly Humans will use robots to achieve this immensely difficult task, robotic systems are already used for almost every other aspect of spaceflight.

Will we pay the cost - we already are, but are we willing to pay more to make it happen faster?


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#62 2008-05-17 17:56:03

JonClarke
Member
From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Problems with Humans on Mars

Turning things upside down usually results in nonsense.

It allows you to test assumptions and logic and see things differently.  It's done all the time in science, engineering and other forms of scholarship generally.  It does not aways work, but it is always helpful and sometimes leads to complete re-thinks.

Just because a cost/kg can be calculated doesn't mean that it has any sense. There's no meaningful correlation between cost per kg of human missions versus robotic ones unless the same types of missions are compared, and that's almost impossible. Likewise it doesn't even make much sense to compare the cost/kg of communication sats with navigation sats, and they are quite close in functionality and location. Comparing the cost/kg of different types of communication sats that have similar capabilities would make sense.

People do such camparisons in industry all the time.  Cast costs per kg is one such measure.

We are comparing the costs and benefits of two different technologies to achieve the same goal, the exploration of Mars.  To make the exercise valid for Mars exploration we need common denominators. Distance traversed, science payload, samples returned.  For cost we can use either a simple total cost or cost per kg.  if you can think of a better measure, than by call means suggest it.

And yes, If someone was making a point about say navsats being intrinsically more costly than comsats, I would use cost per kg as one measure.

wrote:

Human missions are totally different to robotic ones. Human missions are enormously expensive will continue to be so for a long time.

They certainly are, simply because they are larger, not because the technology is more costly. They are certainly going to be more productive.

Jon

Offline

#63 2008-05-18 03:00:54

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

To make the exercise valid for Mars exploration we need common denominators. Distance traversed, science payload, samples returned.  For cost we can use either a simple total cost or cost per kg.  if you can think of a better measure, than by call means suggest it.

The cost per km traversed, cost per kg of returned sample, cost per image - would all make sense.

Exploration cannot be measured in kg.


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#64 2008-05-18 05:15:59

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

Re: Problems with Humans on Mars

Cost benefit analyses are really far more subjective than their proponents would like. That's not say we shouldn't look at some of the basic figures. We need some sort of comparison. But it would be a mistake to base policy on that. 

It's instructive to look at our own everyday lives. We do make some cost-benefit analyses - will that car do a better mileage than this one? But we also take into account lots of other factors e.g. if I move to X I won't ever get to see my friends in Y etc.

So it is with Mars and the Moon I would suggest.  It's all very well taking pricing the sample returned. But how could you ever judge the "quality" of the samples? The fact is that I would still trust the human eye over any  surface robot to identify interesting samples.

Of course if technology can improve so that we enjoy via a robot a "virtual " experience of being on the planet then clearly the balance will begin to change. But at present in terms of utility I value humans over robots. Or rather I value humans PLUS robots over robots ALONE.

But that debate cannot override the fundamental impetus for colonisation of the planets - the urge to seek new homes and attempt to create the good society in these new places.


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

Offline

#65 2008-05-18 08:45:39

Swoosh
Member
From: Australia
Registered: 2008-01-28
Posts: 33

Re: Problems with Humans on Mars

To make the exercise valid for Mars exploration we need common denominators. Distance traversed, science payload, samples returned.  For cost we can use either a simple total cost or cost per kg.  if you can think of a better measure, than by call means suggest it.

The cost per km traversed, cost per kg of returned sample, cost per image - would all make sense.

Exploration cannot be measured in kg.

Cost per image is a good one that caught my attention a few days back whilst cruising wikipedia:

http://en.wikipedia.org/wiki/Image:Vict … e-Mars.jpg

This image represents 3 weeks solid work for one MER.

$400,000,000 * (21 days / 1500 days total mission) = $5,600,000

Pretty expensive shot!

Offline

#66 2008-05-18 09:04:30

Swoosh
Member
From: Australia
Registered: 2008-01-28
Posts: 33

Re: Problems with Humans on Mars

More to add to that. How does the human mission stack up?

Assumptions:

Mission cost: $30 Billion (MarsDirect)
Time to take photo: Half a day (travel to site, setup for EVA, etc)
Total mission time: 2000 man-days on the surface (four man crew for 500 day mission)

$30,000,000,000 * (0.5/2000) = $7,500,000

So the costs are comparable, even assuming a generous half-day for an astronaut to get a decent image. Interesting. I guess another large assumption is that all uses of an astronaut's time are equally valuable. What's a good photo worth compared to knowing the chemical composition of a rock? I suppose we stick to the economist's doctrine of ceterus paribus, all other things equal, for now.

Offline

#67 2008-05-18 09:16:27

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

Yes, it's an impressive piece of work - probably about 100 frames each taken with 3 filters - so about 300 images. Getting the light conditions balanced needs images to be taken at the same time each day, so an astronaut may need to return several times to complete it. Travel to location and setup time starts to add up.

The tricky part is estimating the cost of astronaut time. A crew of six can't all be exploring every day as they need to recover and maintain their hab and equipment. Using the same basis as MER one would have to count the entire development cost which would be a LOT of dosh (probably far more than $30billion, maybe ten times that). Otherwise one could try to estimate the replacement cost of a rover and use an estimated cost per human mission. Human missions initially will be about 500 sols on Mars. The MERs have lasted over 1400 sols. So a lot of unknowns, play with the assumptions and almost any answer is possible. It's very hard to see that a human on Mars could take that photo as cheaply as a robot, unless they used a robot to take it smile


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#68 2008-05-18 14:55:08

Midoshi
Member
From: Colorado
Registered: 2007-07-14
Posts: 157

Re: Problems with Humans on Mars

Very sobering to realize that a shot like that can be done in a few seconds by an amateur photographer on Earth using a 22 megapixel camera costing under $10,000. Really puts in contrast how this stuff is on a different playing field from commercial terrestrial tech.


"Everything should be made as simple as possible, but no simpler." - Albert Einstein

Offline

#69 2008-05-18 16:31:03

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

Yeah, and a shopping trolley can carry the same payload as MER smile

It's interesting to note that both Phoenix and MSL will be using similar resolution CCD technology as MER. Phoenix will have the same 1024x1024 CCD chip but more filters and MSL will have a slightly bigger one (1600x1200) that can also produce HDTV.


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#70 2008-05-21 05:00:19

JonClarke
Member
From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Problems with Humans on Mars

More to add to that. How does the human mission stack up?

Assumptions:

Mission cost: $30 Billion (MarsDirect)
Time to take photo: Half a day (travel to site, setup for EVA, etc)
Total mission time: 2000 man-days on the surface (four man crew for 500 day mission)

$30,000,000,000 * (0.5/2000) = $7,500,000

So the costs are comparable, even assuming a generous half-day for an astronaut to get a decent image. Interesting. I guess another large assumption is that all uses of an astronaut's time are equally valuable. What's a good photo worth compared to knowing the chemical composition of a rock? I suppose we stick to the economist's doctrine of ceterus paribus, all other things equal, for now.

Of course a human mission would get scores to hundreds of photos in a day plus continuous multi-vantage point video coverage.

Jon

Offline

#71 2008-05-21 05:54:29

JonClarke
Member
From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Problems with Humans on Mars

Yes, it's an impressive piece of work - probably about 100 frames each taken with 3 filters - so about 300 images. Getting the light conditions balanced needs images to be taken at the same time each day, so an astronaut may need to return several times to complete it. Travel to location and setup time starts to add up.


On the other hand an astronaut’s camera probably would not have top take separate images through different filters, but would capture multiple bands simultaneously.  Say 10 seconds per frame that is 1000 seconds to collect the panorama – 17 minutes.  But then any astronaut cameras will almost certainly have options like wide angle lenses.  So it might not take 100 frames but only 50.  Alternatively you can  use a  remote controlled camera on a tripod.  An EVA team would set it up and then go away and do something else while the images are being collected and retrieve it when it is done. 

The tricky part is estimating the cost of astronaut time. A crew of six can't all be exploring every day as they need to recover and maintain their hab and equipment.

Six people is three EVA teams.  The Apollo astronauts thought that an EVA every other day was sustainable, the astronauts on shuttle missions to ISS do one every three days on average.  So let’s say one EVA every three days per team.  In a six day working week that is six EVAs, one a day.



Using the same basis as MER one would have to count the entire development cost which would be a LOT of dosh (probably far more than $30billion, maybe ten times that).

What evidence do you have that a human Mars mission would cost anything like $300 million? Not even the infamous 90 day study cost this much!


Otherwise one could try to estimate the replacement cost of a rover and use an estimated cost per human mission. Human missions initially will be about 500 sols on Mars. The MERs have lasted over 1400 sols. So a lot of unknowns, play with the assumptions and almost any answer is possible. It's very hard to see that a human on Mars could take that photo as cheaply as a robot, unless they used a robot to take it smile

Given the fact that a human mission will cover hundreds of times as much ground and have continuous video coverage I think it would be very easy to exceed the number of images.  Let’s take your 500 day surface mission and six person crew, and the probable EVA cycle I have outlined.  That is 70 working weeks, 420 working days.  Let’s say 200 high resolution photos a day, so 84000 in all. Plus 3,360 hours of video at 24 frames a second, that’s more than 290 million lower resolution images.

But exploring Mars is much more than pictures.  It is about science instruments.  MER can deploy about half a dozen crude instruments. MSL perhaps a dozen.  A human mission would be likely to have the following:

Field instruments
•    Thermal emission spectrometer
•    APX
•    Microscopic imager (colour)
•    Sun compass and clinometer
•    Meteorology suite
•    Ionising radiation suite
•    Laser Induced Breakdown Spectrometer (LIBS)
•    Magnetometer
•    Gravitometer
•    Electromagnetic sounding instrumentation
•    IP array
•    Resistivity array
•    Ground penetrating radar
•    Neutron spectrometer
•    Drill core sampler
•    Heat flow probe
•    Geophysical logging tool (gamma, gamma-gamma, neutron, resistivity, sonic, IP)

Field tools
•    hammer
•    Brush
•    25 cm push corer
•    25 cm rock corer
•    2 m hand drill rig
•    Trailer mounted drill rig with capacity of up to 100 m

Geophysical Station
•    Meterology suite
•    Ionising radiation suite
•    Solar radiation suite
•    All sky day-night camera and spectrometer
•    Lidar
•    Radar
•    Magneto-telluric observatory
•    magnetic observatory
•    Seismic monitoring
•    Aerosonde facility
Lab tools
•    Rock/core cutting facility
•    Oven for burning off volatiles
•    Thin section, SEM sample, and biological slide preparation facility

Lab instruments
•    Raman spectrometer
•    Mass spectrometer
•    Mossbauer spectrometer
•    IR spectrometer
•    Atomic force microscope
•    SEM microscope
•    Optical microscopes (polarised, bright and dark field, phase contrast, transmitted & reflected light)
•    XRF
•    XRD
•    Wet chemistry
•    Ice core analysis instrumentation
•    Oven for burning off volatiles
•    X-ray
•    Ultrasound
•    Hyperspectral core logger
•    Age-dating instrumentation (K-Ar, cosmogenics)
•    Organic chemistry suite
•    Metabolism detecting instrumentation
•    DNA fingerprinting
•    Mass spectometer for organics, ices, carbonates, and gases
•    Physiology suite
•    Medical chemistry analytical suite

Some of these instruments are impossible for unmanned missions, others would be very difficult. Ever tried making a thin section, or deploying (and recovering) a EM array, or launching a radiosonde, or taking a dip and strike on the underside of an overhang? Even those instruments that could be carried by unmanned missions would require a dozen or more missions much more sophisticated than MSL or even Viking to deploy them all.  And don’t forget the crewed mission will have much more power available and so will be able to collect measurements faster, with greater accuracy, and more precision. 

But it is not just about the instruments.  It is about having years of professional training and experience, dexterity, mobility, creativity, senses and intuition available on the spot with all these tools at their  disposal, rather stuck at the end of a 40 minute time lag and with only a limited set of data and tools.

But it is not only about human presence.  By its very nature a human mission will bring back 100’ss of kgs of samples, enough for man universities in just about every country of the world to study.  Unmanned missions by their very nature, are stuck to bringing back a few 100 grams, perhaps one kg at the most, from a very limited area, and with much less context information.

Jon

Offline

#72 2008-05-21 06:49:24

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

Re: Problems with Humans on Mars

I think Jon just hit the ball out of the ground!


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

Offline

#73 2008-05-21 07:18:41

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

Re: Problems with Humans on Mars

If we can assume that a future astronaut will  have a camera that can take a equivalent panorama in 17 minutes, then it's only fair to assume that a future robot will also have one.

On STS-123 shuttle astronauts did five EVAs within nine days, but an enormous amount of preparation was necessary and they had the support of three ISS crew and several other shuttle crew. It seems unlikely that a Mars crew could keep up that pace for a 500 day mission especially as they have to maintain their base, suits and health.

As I wrote earlier, one way of estimating the cost to develop the infrastructure to enable Mars missions is to add the current Lunar program ($104B), the Lunar Outpost (say $50 billion) and the cost of developing the extra vehicles and habitats (another $100 billion?) and add in the Mars robotic program say $10 billion more .. that's $264 billion. Yes it's a WAG but $30 billion is IMHO far too low.

The comparison discussion was focused on how much the Cape Verde panorama would cost if it was done by a human on Mars, of course considering all the other things that humans can do and as well as future robots will be capable of doing makes the picture, pun intended,  far more complicated.

It's about much more than collecting images, data or even samples, it's about human presence and experience, both that of the astronauts themselves and what they share with the entire world.


[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Offline

#74 2008-05-22 05:01:18

JonClarke
Member
From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Problems with Humans on Mars

If we can assume that a future astronaut will have a camera that can take a equivalent panorama in 17 minutes, then it's only fair to assume that a future robot will also have one.

It’s not a fair assumption.  Unmanned missions have power, mass, computing and communications constraints that crewed missions don’t have. An astronaut on the surface of Mars now, using existing technology, would be able to make paanoramas in minutes.  But our rovers cannot.


On STS-123 shuttle astronauts did five EVAs within nine days, but an enormous amount of preparation was necessary and they had the support of three ISS crew and several other shuttle crew. It seems unlikely that a Mars crew could keep up that pace for a 500 day mission especially as they have to maintain their base, suits and health.

It is the opinion of the Apollo astronauts that EVAs every other day per EVA team is feasible.  Saying one every three days is therefore conservative.  But if you think that it is optimistic, why don’t you come up with what you think is a realistic rate of EVAs, per person with reasons?  One EVA a week, one fortnight, one a month?

As I wrote earlier, one way of estimating the cost to develop the infrastructure to enable Mars missions is to add the current Lunar program ($104B), the Lunar Outpost (say $50 billion) and the cost of developing the extra vehicles and habitats (another $100 billion?) and add in the Mars robotic program say $10 billion more .. that's $264 billion. Yes it's a WAG but $30 billion is IMHO far too low.

OK, I see what you are coming from.  But that is not the way to do it.  Lunar programs, unmanned missions, are all sunk costs as far as a Mars mission as concern and cannot be legitimately included in the costing.  It would be like including all previous space programs, both Russian and US, into the cost of the ISS.  As to whether your 100 billion for the actual mars mission development is reasonable, it would depend on what you envisage developing for that

The comparison discussion was focused on how much the Cape Verde panorama would cost if it was done by a human on Mars, of course considering all the other things that humans can do and as well as future robots will be capable of doing makes the picture, pun intended,  far more complicated.

In what way?

It's about much more than collecting images, data or even samples, it's about human presence and experience, both that of the astronauts themselves and what they share with the entire world.

No argument from me on this.  It is the intangible real reasons that matter.  But crewed missions can also be justified on tangible returns as well.

cheers

Jon

Offline

#75 2008-05-22 05:19:40

JonClarke
Member
From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Problems with Humans on Mars

Exploration cannot be measured in kg.

Yes it can.  Returned samples are much more scientifically valuable than those analysed in situ on Mars, or even in a well equipped laboratory on Mars. 

More samples means a greater diversity of materials and sample types.  It means a greater number of analytical techniques can be applied allowing more diverse studies.  It means that more repeat analyses can be run, allowing greater precision.  It means more researchers can investigate the samples allowing greater range of skills being brought to plaay.  It also means a greater amount of sample can be archieved for future generations with new and better analytical techniques.

This is why more work has been and is being done on the 400 kg of Apollo samples than on the few 100 g of Luna samples.

Jon

Offline

Board footer

Powered by FluxBB