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#26 2007-01-29 22:44:22

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

Re: Improving Mars Direct and DRM III

Perhaps a regular ERV kept in mars orbit would do the trick?

How long does the ERV take to manufacture the necessary fuel? And how does this compare with DRM's MAV?


- Mike,  Member of the Clean Slate Society

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#27 2007-01-29 22:50:35

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Improving Mars Direct and DRM III

The DRM ERV never lands, it stays in Mars orbit, and the crew reaches it via the MAV.

You could put a "regular" MAV payload (empty fuel tanks + ISRU/equipment) in Mars orbit in the event the landed one failed, but remember that ISRU requires Hydrogen imported from Earth in its storage tanks, and that wouldn't last all that long even if you brought extra in lieu of the rover/equipment.

I think the only real option for redundancy and global-wide exploration with DRM is to place a fully fueled MAV in Mars polar orbit, with the ability to land with accuracy near the stranded crew and launch them to the ERV.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#28 2007-01-29 23:15:13

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

Re: Improving Mars Direct and DRM III

If you have a rover range of several hundred kilometers then you have a wide range of possible landing sites.

Personally, I don't see what would be the big deal about landing each mission about 800 kilometers (500 miles) from the last. 

You're still covering alot of new ground with each landing while still remaining close enough to access the earlier missions equipment in case it is needed.

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#29 2007-01-29 23:40:54

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

Re: Improving Mars Direct and DRM III

This is why:

http://themis.asu.edu/landingsites/MSL_ … _table.pdf

I bet most of these sites aren't anywhere near 1000km from each other.

Remember that the surface area of mars is equal to all the continents on earth. We cannot effectively explore such a vast land if we are restricted to sites only 800km from the previous. That would be inefficient and boring.


- Mike,  Member of the Clean Slate Society

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#30 2007-01-29 23:50:48

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

Re: Improving Mars Direct and DRM III

I think the only real option for redundancy and global-wide exploration with DRM is to place a fully fueled MAV in Mars polar orbit, with the ability to land with accuracy near the stranded crew and launch them to the ERV.

If that could be done, then why hasn't DRM adopted it? It doesn't seem right that you could dispense with ISRU, yet at the same time gain that extra level of redundancy. That would be too easy. Where's the catch?


- Mike,  Member of the Clean Slate Society

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#31 2007-01-30 10:30:56

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Improving Mars Direct and DRM III

The catch is that:

1) Its questionable if the MAV can loiter on orbit for long periods due to boiloff of the fuel. LOX/Methane is much

2) DRM-III uses lighter vehicle than DRM-I, where the possibility of a no-ISRU MAV was discussed. It is possible that the baseline DRM-III payload mass is insufficient to land a fully fueled MAV.

However I think that with the higher payload of Ares-V, that if NASA were to use the excess payload for more fuel, the vehicle mass could be increased to meet this threshold and restore DRM-I sized payloads.

Then the question becomes, how long can the MAV loiter in orbit before too much of its fuel boils off? Unfortunately I bet the answer to this question is not very long.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#32 2007-02-08 08:20:12

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,073

Re: Improving Mars Direct and DRM III

Does anyone know the mass numbers for the refueling station lander that will create methane for crew return (MAV) from surface to the orbiting ERV?

Do we know if we are capable of landing such mass on the mars surface and its reliablity of success?

Is the mass simular to the LSAM?

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#33 2007-02-08 10:41:31

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Improving Mars Direct and DRM III

It can't weigh that much, the MAV and the ISRU plant w/ reactor + hydrogen are both riding together on the same vehicle. The MAV doesn't weigh much empty.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#34 2007-02-08 13:34:21

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

Re: Improving Mars Direct and DRM III

Some comments, mostly from Doug Cook, made during telecon budget briefings on 5 Feb 2007

o ESMD (Exploration Systems Mission Directorate) has started work on a revision of DRM 3.0
o some of the same people who worked on DRM 3.0 are working on the revision (Doug Cook presumably is one)
o colaboration with SMD (Science) and ARMD (Aeronautics Research)
o work to be based on DRM 3.0, best knowledge and use of Ares vehicles
o Analog sites will help for both lunar and Mars missions
o MSL heatshield will be instrumented to help design of future Mars landers
o revision update would be available late summer 2007


Let's go to Mars and far beyond -  triple NASA's budget !   #space channel !!    - videos !!!

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#35 2007-02-08 16:55:22

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Improving Mars Direct and DRM III

Some comments, mostly from Doug Cook, made during telecon budget briefings on 5 Feb 2007

o ESMD (Exploration Systems Mission Directorate) has started work on a revision of DRM 3.0
o some of the same people who worked on DRM 3.0 are working on the revision (Doug Cook presumably is one)
o colaboration with SMD (Science) and ARMD (Aeronautics Research)
o work to be based on DRM 3.0, best knowledge and use of Ares vehicles
o Analog sites will help for both lunar and Mars missions
o MSL heatshield will be instrumented to help design of future Mars landers
o revision update would be available late summer 2007

Yay!


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#36 2007-09-08 08:19:28

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

Re: Improving Mars Direct and DRM III

This plan has been superceded by this plan.


- Mike,  Member of the Clean Slate Society

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#37 2014-01-19 13:46:15

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,073

Re: Improving Mars Direct and DRM III

NASA’s Mars Design Reference Mission Goes Nuclear (2001)

In October 2001, nuclear engineers at NASA’s Glenn Research Center (GRC) in Cleveland, Ohio, led by Stanley K. Borowski, Advanced Concepts Manager in GRC’s Space Transportation Project Office, described a variant of NASA’s 1998 Mars Design Reference Mission (DRM) 3.0 based on Bimodal Nuclear Thermal Rocket (BNTR) propulsion. The BNTR DRM concept, first described publicly in July 1998, evolved from nuclear-thermal rocket mission designs Borowski and his colleagues developed during the abortive Space Exploration Initiative (1989-1993).
In the absence of guidance from Houston, NASA GRC developed a pair of DRM 3.0 variants: a solar-electric propulsion (SEP) DRM 3.0 and the BNTR DRM 3.0 considered here.

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#38 2014-01-20 05:32:13

Quaoar
Member
Registered: 2013-12-13
Posts: 600

Re: Improving Mars Direct and DRM III

SpaceNut wrote:

Does anyone know what the maximum volume and mass of any mars landers that we would send to the surface can be?

Also how much of that same lander would be cargo or payload?

According to this study ( http://www.ssdl.gatech.edu/papers/confe … 9-6684.pdf ):

limits for direct entry of a blunt body: 10 m shield diameter 40 mT entry mass, 20 mT payload, supersonic retropropulsion

limits for entry from orbit of a blunt body: 15 m shield diameter 100 mT entry mass, 40 mT payload, 50 m diameter inflatable ballute

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#39 2014-01-20 07:56:57

Quaoar
Member
Registered: 2013-12-13
Posts: 600

Re: Improving Mars Direct and DRM III

GCNRevenger wrote:

Then the question becomes, how long can the MAV loiter in orbit before too much of its fuel boils off? Unfortunately I bet the answer to this question is not very long.

LOX LCH4 are soft cryogenic not so hard to cool like LH2, so no problems using a good multilayered insulation and a solar powered active cooling system.

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#40 2014-01-20 07:59:58

Quaoar
Member
Registered: 2013-12-13
Posts: 600

Re: Improving Mars Direct and DRM III

SpaceNut wrote:

Does anyone know the mass numbers for the refueling station lander that will create methane for crew return (MAV) from surface to the orbiting ERV?

Do we know if we are capable of landing such mass on the mars surface and its reliablity of success?

Is the mass simular to the LSAM?

4802 kg in DRM1 and 3941 in DRM3: you can find all the data here:

http://ston.jsc.nasa.gov/collections/tr … 07-ADD.pdf

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#41 2014-01-20 12:42:43

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,073

Re: Improving Mars Direct and DRM III

I have seen protective shroud designs of 10M or 12M but none have been built for lockheeds Atlas heavy with actual inside diameters about a meter less.

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