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#1 2007-10-20 09:12:55

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

Re: Design Reference Mission 5.0

drm5beu3.jpg
Ripped from From the Moon to Mars (PDF 2MB) 1 Oct 2007

So it looks like this: four Ares V launching two separate payloads to Mars followed by another two Ares V and one Ares I for the transit vehicle and crew. Wow, that's quite a mission!


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#2 2007-10-20 09:16:46

cIclops
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Re: Design Reference Mission 5.0

drm5aao8.jpg
Flight sequence from the same document above - 1 Oct 2007

It's a long time to 2031 - it all looks feasible, but let's do it sooner!

The overlap provides good redundancy with a second habitat available and a spare lander in orbit.

Note that the text says 6 Ares V are needed not 7 as shown in the diagram.

Ares V #1 - puts large EDS into LEO with no cargo, maximizing EDS fuel load
Ares V #2 - puts Habitat into LEO with partially fueled EDS
Hab/EDS + large EDS dock and depart for LMO
Hab lands on surface

Ares V #3 - puts large EDS into LEO with no cargo, maximizing EDS fuel load
Ares V #4 - puts Lander into LEO with partially fueled EDS
Lander/EDS + large EDS dock and depart for LMO
Lander waits in LMO

Ares V #5 - puts large EDS into LEO with no cargo, maximizing EDS fuel load
Ares V #6 - puts Transit Vehicle (MTV) into LEO with partially fueled EDS
MTV/EDS + large EDS dock
Ares I launches with Orion and 6 crew to LEO
Orion docks with MTV stack and departs for LMO
Orion/MTV dock with Lander in LMO

Lander undocks and takes crew to the surface near the Hab
Crew explore surface

Crew ascend to LMO with lander and dock with Orion/MTV
Orion/MTV undocks from lander and crew returns to Earth
Orion separates from MTV near Earth and lands.

An important caveat on page 3: "This probably does not represent the way we will end up going to Mars"


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#3 2007-11-09 14:46:27

publiusr
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From: Alabama
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Re: Design Reference Mission 5.0

It seems doable at the very least.

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#4 2007-11-09 15:07:27

cIclops
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Re: Design Reference Mission 5.0

Doable indeed! It integrates Constellation into DRM, but many many more details are needed, for example it's not clear if NTP is required.


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#5 2007-11-10 12:23:12

Tom Kalbfus
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Re: Design Reference Mission 5.0

What exactly happens to the Mars ship once the mission is over with?

It didn't exactly say how the Mars ship gets from Low Earth Orbit to Mars orbit. Does it simply use the chemical upper stages of the Ares V to put it directly into Mars orbit?
Seems fairly wasteful of propellent if done that way.

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#6 2007-11-10 17:28:46

cIclops
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Re: Design Reference Mission 5.0

What exactly happens to the Mars ship once the mission is over with?

It didn't exactly say how the Mars ship gets from Low Earth Orbit to Mars orbit. Does it simply use the chemical upper stages of the Ares V to put it directly into Mars orbit?
Seems fairly wasteful of propellent if done that way.

The Lander will be left in LMO, the MTV will be jettisoned before Earth reentry.

Yep, there is not much detail, it's only an overview. The MTV and the Lander will probably use EDS stage(s) to enter LMO. Aerobraking may be possible too, there are a lot of trades.  The Hab will probably make a direct entry and land. A nuclear upper stage would be very helpful for the MTV, it would reduce crew transit time and increase payload.  Hopefully more detail will be available soon.


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#7 2007-11-11 09:09:08

Tom Kalbfus
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Re: Design Reference Mission 5.0

What gets me is why they seemingly use a chemical rocket to deliver the cargo. I think an ion drive would maximize the amount of cargo deliverable to Mars orbit. Also the technology doesn't match the date of the proposed Mars mission. I think by 2031 they'll have better things than expendible Ares V rockets or they ought to at least. If the mission was to be done in 2031, they should use a scramjet space shuttle to deliver the parts into low Earth orbit and assemble a reusable Mars Ship in low Earth orbit. I think we should at least push for George H. W. Bush's original target date, July 20, 2019.

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#8 2007-11-11 10:01:45

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

Re: Design Reference Mission 5.0

What gets me is why they seemingly use a chemical rocket to deliver the cargo. I think an ion drive would maximize the amount of cargo deliverable to Mars orbit. Also the technology doesn't match the date of the proposed Mars mission. I think by 2031 they'll have better things than expendible Ares V rockets or they ought to at least. If the mission was to be done in 2031, they should use a scramjet space shuttle to deliver the parts into low Earth orbit and assemble a reusable Mars Ship in low Earth orbit. I think we should at least push for George H. W. Bush's original target date, July 20, 2019.

DRM 5.0 may use nuclear rockets, we'll see.

Ion drive technology requires a lot of electrical power, that either means really BIG solar arrays or a nuclear reactor. Dawn has 10 kW of power from solar arrays that are 20m across to move 1.2 tons of spacecraft. It takes Dawn 17 months to flyby Mars, it would take much longer to decelerate into LMO. A nuclear reactor would be necessary to provide enough power for multiple ion engines, so why not use NTP? Trading Chemical v ion v nuclear is complex and requires a lot of information and knowledge.

It's hard to say what technologies will be available for use in 2031. 2019 may be impossible even with unlimited funding, but it would be quite a goal to set!


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#9 2007-11-11 10:44:15

Tom Kalbfus
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Re: Design Reference Mission 5.0

It appears that 6 Ares V rockets for the cargo and 6 Ares V rockets for the habitable section would be quite expensive, and its all because they need to deliver their return fuel into low Mars orbit instead of using insitu fuel production on Mars' surface, instead they just use that to get back into Low Mars orbit. The Chinese could probably beat us, if we go this route. The undemocratic Chinese government might well be willing to take greater risks and if things go wrong, just shrug off the consequences and try again. No doubt some high Chinese Government officials may be taking a look at Zubrin's Mars Direct approach.

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#10 2007-11-11 10:51:05

cIclops
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Posts: 3,230

Re: Design Reference Mission 5.0

It appears that 6 Ares V rockets for the cargo and 6 Ares V rockets for the habitable section would be quite expensive, and its all because they need to deliver their return fuel into low Mars orbit instead of using insitu fuel production on Mars' surface, instead they just use that to get back into Low Mars orbit.

It's 6 Ares V plus 1 Ares I per mission (see my previous message). The Lander and the Hab stay at Mars, only the MTV and Orion will return.

ISRU would help enormously, the Lander would be much lighter and perhaps deliver fuel to the MTV for the return trip.


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#11 2007-11-12 02:11:31

Tom Kalbfus
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Re: Design Reference Mission 5.0

There were 6 Saturns used in total for all the Successful Apollo missions that reached the Moon, so we might assume that the cost of each manned Mars mission would be the sum total of Apollo missions 11, 12, 14, 15, 16, and 17. Those are six Apollo missions which used six Saturn Rockets which are roughly equivalent to the proposed Ares V rockets.

I wonder what merit NASA sees in doing a Mars mission this way? Do they expect a six-fold increase in their manned space budget over that during the Apollo missions? Do you actually expect NASA to field an expedition like this every two years and sustain it indefinitely?

Seems to me that a colonization mission would bring a greater return for the money spent rather than a mission where the majority of the money spend occurs in bring the astronauts back home. We could sustain a human presence there indefinitely, and if we plan on making our presence there permanent anyway, why spend the enourmous amount of money involved just to change crews, just send resupply ships.

Another thing is, wouldn't it be cheaper to build rockets with 6 time the lift capacity as an Ares V rocket than to build six Ares V rockets? It seems to me that if you need six Ares V rockets to launch one mission, your using the wrong sort of rocket.

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#12 2007-11-12 03:01:08

cIclops
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Registered: 2005-06-16
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Re: Design Reference Mission 5.0

There were 6 Saturns used in total for all the Successful Apollo missions that reached the Moon, so we might assume that the cost of each manned Mars mission would be the sum total of Apollo missions 11, 12, 14, 15, 16, and 17. Those are six Apollo missions which used six Saturn Rockets which are roughly equivalent to the proposed Ares V rockets.

I wonder what merit NASA sees in doing a Mars mission this way? Do they expect a six-fold increase in their manned space budget over that during the Apollo missions? Do you actually expect NASA to field an expedition like this every two years and sustain it indefinitely?

<snip>

Another thing is, wouldn't it be cheaper to build rockets with 6 time the lift capacity as an Ares V rocket than to build six Ares V rockets? It seems to me that if you need six Ares V rockets to launch one mission, your using the wrong sort of rocket.

Yes, each Saturn V could lift about 120 tons into LEO, so one Mars DRM 5.0 mission would be about the same as 6 Apollo missions. That's a good way to see how difficult and expensiive it will be.

Saturn V was very expensive, about $2 billion per flight in 2005 dollars. Ares V is estimated to have a marginal cost of about $300 million plus fixed costs. NASA says it can afford a Mars mission every two years within its current budget, the cost would be about $3 billion per mission. All these numbers are of course extremely rough estimates, we are talking about missions flying in the 2030s.

Ares V is at the limit of current technology, it will be about 5 times more powerful than any other launcher in existence.


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#13 2007-11-13 00:35:34

Michael Bloxham
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From: Auckland, New Zealand
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Posts: 426

Re: Design Reference Mission 5.0

cIclops is right. If all goes to plan, flying these Ares-V's should be just as routine as flying the Shuttle has been... We could easily fly 5 of these things a year, more if we consider that they are unmanned (less safety risk).

So the real question is, what shall we do with the excess launch capacity?


- Mike,  Member of the Clean Slate Society

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#14 2007-11-13 03:08:50

cIclops
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Registered: 2005-06-16
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Re: Design Reference Mission 5.0

So the real question is, what shall we do with the excess launch capacity?

DRM 5.0 requires four Ares V in the first year ( 2 for the Hab and 2 for the Lander) and then two years later it needs another two Ares V for the MTV plus an Ares I for the Orion/crew launch.

By this time it's assumed that the Lunar Outpost will have expanded and be permanently occupied, this will require two missions a year to rotate crew and maybe one more for cargo. That's another three Ares V and one more Ares I every year.

NEO missions could also use an Ares V together with an Ares I.

Ares V will be the most powerful launcher around for a while, so it may also be used for launching large observatories or deep space missions requiring a lot of propellant.   See the Ares V forum for more details


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#15 2007-11-14 00:50:42

Tom Kalbfus
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Re: Design Reference Mission 5.0

Could they be used for asteroid mining? Perhaps those boosters could be sold on the private sector to mining companies wishing to mine the asteroids for valuable minerals, that is an activity, I would like to see started. So much has been written about mining the asteroids, yet so little has been done. Also the ability to mine the asteroids also lends the ability to change the orbits of asteroids, thereby reducing the threat of eventuall asteroid collisions with Earth.

An Ares V rocket can deliver a really massive thermonuclear warhead if necessary to deflect an asteroid with for instance.

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#16 2007-11-15 18:09:45

Dayton Kitchens
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From: Norphlet, Arkansas
Registered: 2005-12-13
Posts: 183

Re: Design Reference Mission 5.0

This looks to me like the same equipment and mission architecture from that new Science Channel series "Living Mars".

This all seems like major steps back.

What happend to Mars Semi-Direct that would've required only three Ares V type of launches per mission.

It seems like we're going in entirely the wrong direction.

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#17 2007-11-16 01:04:15

Michael Bloxham
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From: Auckland, New Zealand
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Posts: 426

Re: Design Reference Mission 5.0

I agree. Considering Zubrins studies, what sort of mission could be achieved using three launches of the Ares V using the pre-developed Lunar EDS as the departure stage?

Perhaps the Lunar EDS could be scaled easily to meet MarsDirect requirements?


- Mike,  Member of the Clean Slate Society

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#18 2007-11-16 04:24:13

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

Re: Design Reference Mission 5.0

This all seems like major steps back.

What happend to Mars Semi-Direct that would've required only three Ares V type of launches per mission.

It seems like we're going in entirely the wrong direction.

It's interesting that seven years after DRM 3.0 the basic architecture remains the same. Having sufficient mass in transit, LMO and on the surface seems to be the reason for two Ares V per phase. An Ares V can only put about 50 tons into TMI and maybe only 20 tons on the surface. That's not much for 6 crew for 300 days.

This is just a brief overview, more details are necessary to see why.


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#19 2007-11-16 06:08:25

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

Re: Design Reference Mission 5.0

I agree. Considering Zubrins studies, what sort of mission could be achieved using three launches of the Ares V using the pre-developed Lunar EDS as the departure stage?

Perhaps the Lunar EDS could be scaled easily to meet MarsDirect requirements?

Zubrin's Mars Direct relies on ISRU to produce fuel for the ascent vehicle and can only support a crew of four. ISRU technology hasn't been proven yet, it will need a full demonstration before crew can depend on it to return to Earth. ISRU would be extremely helpful in reducing mass requirements to the surface and maybe later for the MTV. Six crew offer far more capacity for exploration and resilience to mishaps.

Lunar EDL is not applicable to Mars. There's no atmosphere on the Moon and there is one on Mars, this has a serious impact on EDL design


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#20 2007-11-17 21:36:47

Michael Bloxham
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From: Auckland, New Zealand
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Posts: 426

Re: Design Reference Mission 5.0

Sorry, I meant EDS, not EDL.


- Mike,  Member of the Clean Slate Society

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#21 2007-11-18 11:13:21

Tom Kalbfus
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Re: Design Reference Mission 5.0

I agree. Considering Zubrins studies, what sort of mission could be achieved using three launches of the Ares V using the pre-developed Lunar EDS as the departure stage?

Perhaps the Lunar EDS could be scaled easily to meet MarsDirect requirements?

Zubrin's Mars Direct relies on ISRU to produce fuel for the ascent vehicle and can only support a crew of four. ISRU technology hasn't been proven yet, it will need a full demonstration before crew can depend on it to return to Earth. ISRU would be extremely helpful in reducing mass requirements to the surface and maybe later for the MTV. Six crew offer far more capacity for exploration and resilience to mishaps.

Lunar EDL is not applicable to Mars. There's no atmosphere on the Moon and there is one on Mars, this has a serious impact on EDL design

Seems to me that we'd also have to prove that we can store cryogenic rocket fuel in LMO for about a year if the Design Reference Mission is to work. One must also consider what the expense of a mission without ISRU would be versus the cost of proving ISRU. I don't think we have to go to Mars to prove ISRU, I think it can be done right here on Earth. Seems to me that building whatever facility would be required to simulate Martian conditions would be alot cheaper than building 6 Ares V rockets and launching a DRM without ISRU. Also the chances of such a mission being carried out get smaller as the cost of the mission gets larger. I'd rather do 3 Mars missions with 6 Ares V Rockets and 3 Ares I rockets than one mission with 6 Ares V Rockets unless that mission were to carry 12 astronauts to Mars.

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#22 2007-11-18 12:41:32

cIclops
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Re: Design Reference Mission 5.0

Seems to me that we'd also have to prove that we can store cryogenic rocket fuel in LMO for about a year if the Design Reference Mission is to work. One must also consider what the expense of a mission without ISRU would be versus the cost of proving ISRU. I don't think we have to go to Mars to prove ISRU, I think it can be done right here on Earth. Seems to me that building whatever facility would be required to simulate Martian conditions would be alot cheaper than building 6 Ares V rockets and launching a DRM without ISRU. Also the chances of such a mission being carried out get smaller as the cost of the mission gets larger. I'd rather do 3 Mars missions with 6 Ares V Rockets and 3 Ares I rockets than one mission with 6 Ares V Rockets unless that mission were to carry 12 astronauts to Mars.

The MTV has to wait 300 days in LMO after departing Earth, so about 500 days in all.  The Lander waits in LMO about three years! Storing cryogenics is possible for that long, but it requires more mass for the insulation and cooling system. This is where Methane has an advantage as its boiling point is much higher than Hydrogen.

A real test of the critical ISRU system on Mars will be necessary, it has to operate in the Martian environment and gravity after landing on the the surface, no amount of testing can fully simulate that. This a good opportunity for a Mars sample return mission, no lives would be at risk and the basic technology could be demonstrated. Zubrin has published a study on such a mission. BTW DRM 5.0 requires six Ares V and only one Ares I.


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#23 2007-11-19 01:03:48

Michael Bloxham
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From: Auckland, New Zealand
Registered: 2002-03-31
Posts: 426

Re: Design Reference Mission 5.0

no amount of testing can fully simulate that.

Yeah, but thoroughly testing it on the ground first isn't a bad idea. Better than not bothering at all.


- Mike,  Member of the Clean Slate Society

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#24 2007-11-19 06:50:19

Dayton Kitchens
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From: Norphlet, Arkansas
Registered: 2005-12-13
Posts: 183

Re: Design Reference Mission 5.0

The whole purpose of the Mars Semi-Direct route was that if something happened to prevent fuel manufacturing on Mars, you could save the mission by using a fourth launch to send a FUELED ascent vehicle to the Martian surface.

So Mars Semi-Direct took into account the possible failure of in situ fuel production.

And Mars Semi-Direct was also designed for six astronauts if IIRC.

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#25 2007-11-19 08:45:33

Tom Kalbfus
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Re: Design Reference Mission 5.0

The whole purpose of the Mars Semi-Direct route was that if something happened to prevent fuel manufacturing on Mars, you could save the mission by using a fourth launch to send a FUELED ascent vehicle to the Martian surface.

So Mars Semi-Direct took into account the possible failure of in situ fuel production.

And Mars Semi-Direct was also designed for six astronauts if IIRC.

If something happened to prevent in-situ fuel production, you would post pone the manned mission to Mars and instead fix the problem and send another ascent stage to the Mars surface. The entire manned mission waits on the ability to produce fuel on Mars, and it doesn't go until the full amount of fuel required to return to Earth is produced. You would trade that risk with the risk that the second ascent stage when sent by Mars Semi-Direct might crash into the surface when needed and leave the astronauts stranded?

I really don't think low Mars gravity is needed for in-situ fuel production. We can set up a chamber on Earth with a simulated Martian Atmosphere and temperature and try it out. Anything that works under Earth gravity will also work under Mars gravity. Basically what your talking about here is the ability of the ascent stage to hold itself up under Earth gravity, and if it can do that, it can also hold itself up under weaker Mars gravity, I do not doubt it for an instant. If you really want we could spend the extra money and launch a Mars ascent stage into low Earth orbit attach it to a cable and centrifuge it to simulate Mars gravity, but I don't think we will find out anything we didn't already know. Its the chemical process we are testing, on the molecular scale gravity fields of Earth or Martian intensity really don't matter that much.

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