New Mars Forums

Marsman

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Registered: 2005-08-30

Posts: 146

Website

Re: Marsdrive Mission Design

I'm not sure if I have posted this here yet but in our new human mission design project we have going and our project site, we have opened a new yahoo groups discussion forum as neutral place for interested people to input without necessarily joining the design team and so you can get a feel for what we are doing with this design. Currently we have 10 in our team and are lead by Ron Cordes a retired Apollo engineer with extensive aerospace experience and we are looking for help in the many different areas this design has. You can find the new discussion group here- http://tech.groups.yahoo.com/group/marsdrivemission/

Or if you would like to help us in other ways (or have any questions)let us know at info@marsdrive.com

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welcome to [url=http://www.marsdrive.net]www.marsdrive.net[/url]

SpaceNut

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From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Marsdrive Mission Design

A little background is in order for Marsman as he is known by on http://www.redcolony.com/forum/, http://www.newmars.com/forums/ and yes on http://www.marsdrive.com/phpBB2/. I too am working towards a mission design as a member of this team. MarsDrive is hoping to pool together the best minds that are willing to work on the project.

The new yahoo group web site was in hope to foster a nuetral ground approach but if you are really interested come and visit the MarsDrive site. There currently is an admin area setup for the team and if you have the right stuff you can be granted access to that area as well.

Currently the team is accessing all previous design reference materials as to aid in this project as part of the review process. We are seeking knowledgeable people who share a common vision of men walking and living on Mars to help.

SpaceNut

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From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Marsdrive Mission Design

Oh I forgot that he is known by MarsDrive on the NASA Spaceflight forums http://forum.nasaspaceflight.com 

There is a ongoing thread New Mars Mission Design- Team Members Needed

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Here's my suggestion (I thought of it while in the shower an hour ago in response to your post):

Radical Manned Mars Mission Architecture:

- Utilizing the Ares V SDLV and Orion derived Hab architecture. It is a direct continuation of Project Constellation.

- Under the plan, an ERV, together with the required in-situ technology and large nuclear power source, is not initially required, if at all. This enables the mission to be executed immediately after the new Lunar goals have been fulfilled.

- Initially, a Hab module is all that is required. This will be smaller than the Mars Direct hab, with a crew of 3, but will contain vastly more consumables.

- After the crew safely lands on the surface, the goal becomes increasing the crews tenure and ability to perform useful science.

- To meet these goals, succesive deliveries are of cargo vehicles, which contain more consumables, spare parts, scientific equipment, etc.

- These cargo vehicles are based directly on the Hab architecture, and may even provide a substitute living space in case of primary hab failure; thus further improving crew survivability.

- One particularly important piece of cargo may be a wheeled truss assembly, together with a small RTG power source, both of which can be easily bolted to the frame of the Hab to make it mobile.

- Having a mobile hab greatly increases science return, and at the same time improves crew morale. I beleive it is also a much safer alternative to long-range rover sorties.

- The 'initially one-way' mission architecture is politically unkillable, and also much more sustainable under NASA's new fixed budget.

- This means surface operations can be gradually expanded as more crews are sent, along with the successive cargo vehicles required to sustain them.

- Over time, the technology required to bring the crews back home may eventually develop. In fact, the uniquely flexible 'initially one-way' architecture will not only ensure continuous funding over many years (in order to sustain the crews on the surface), but may also practically guarantee that the funding is made available in order to develop the technology required to bring them home safely.

- Perhaps the beauty of this plan then, is not in its cost savings, but in the way in which it practically guarantees funding. However, the plan would require vastly less initial development costs, and would therefore be very easy to implement.

- The other issue is that of asset building and science return. Previous mission architectures have simply discarded previous assets (science equipment, life support, energy supplies, etc.) on the surface. With this new architecture, assets are kept with crew for a much longer period.

- The number one asset is the crew themselves, and this is why the architecture should have way more bang-for-buck than previous architectures. By keeping the crew on the surface for longer, much more science can be accomplished, and there is the benefit of building on previous knowledge.

- The crew will have the best science equipment available to them in succesive cargo missions. This means that samples are not needed to be returned to Earth for analysis. All the necessary data will simply be beamed back to Earth.

Summing it up:

* Sending the crew is relatively cheap and easy.

* Sustaining the crew is relatively cheap and easy.

* Getting them back safely is the difficult and expensive bit.

* But once they're there, no politician would dare condemn them to the surface. Funding would be guaranteed.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

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From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Before anyone says sustaining the crew isn't cheap: What I mean is, there is no big development costs required. Just an extra launch required every now and then to sustain the crew.

It's a strategy that would make everyone happy really. I imagine it could be a natural continuation of the Apollo Redux. Then, as now and before, NASA will want to find ways to justify keeping their workforce employed. Congress won't want to give out any extra cash. Its a sustainable solution that fits better with the new NASA philosophy.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

The plan is more cunning than I originally thought. Think about it: It will be the new ISS. But without the shear pointlessness:

At first it will be a political solution to maintain the NASA army, then once the first crew is sent, it will become politically unkillable.

Pure genious!

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

cIclops

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Registered: 2005-06-16

Posts: 3,230

Re: Marsdrive Mission Design

Without a realistic way to rescue the crew, any such plan would would never be approved by a media dominated government.

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[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]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

You rescue them by sending them a replacement habitat... in the form of the first cargo delivery vehicle (as mentioned).

Attempting to bring them back home would be way more risky. Actually, if the hab became unhabitable either in transit or on the surface, both the Mars Direct and Design Reference Mission plans would be no better.

This plan is bulletproof.

I will now unceremoniously offer it to the Marsdrive people as a gift.

Use it wisely.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

cIclops

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Registered: 2005-06-16

Posts: 3,230

Re: Marsdrive Mission Design

We kicked this idea around a while ago - see my post Jan 12 2007 - remember?

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[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]

Michael Bloxham

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From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Yeah, sorry cIclops. The idea of a one-way mission is not new.

What I bring to the table is the idea that a mission plan that begins as a one-way architecture does not necessarily have to end as one.

Perhaps it can be thought of as a Mars Direct mission, but in reverse, where the Hab is developed and sent first, and the more expensive ERV is developed and sent later.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Actually, I'm showing my ignorance. Reading your post and others, it seems the idea was kicked around. And I'm not surprised. The idea is quite obvious.

Good then, as obvious solutions are inherently more meritable.

With that said, I look forward to seeing it integrated into a proposal.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

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From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

There are two critical ideas which I think I have brought to the table: (1) Hab mobility, and (2) The option to resupply with conventional rockets in case of a problem or cancellation of the HLLV program.

In all likelyhood (2) would never be needed as the HLLV would be unkillable so long as it is required to send the finished ERV. Nevertheless, the ability to deliver payloads on conventional launch vehicles may play a minor support role. Also, the ability to ensure the crews survival for many years despite of HLLV cancellation would make the one-way mission more politically palatable (the alternative being the fate of the crew being tied directly with the HLLV).

While the second point is politically valuable, it is the first point which is much more valuable to the mission architecture itself. A mobile Hab would be essential for long-term sorties (perhaps on the order of 5 to 10 years on the surface), as it would break crew monotony. At the same time, science return may be of orders of magnitude greater. Also, making the Hab mobile would be much safer than relying on long-range rover sorties.

However, having the Hab roam across the surface presents many of its own problems. But with the unique way in which this architecture relies on continued re-supply, the problem is automatically addressed: Cargo vehicles are simply landed nearest to the location of the Hab at that particular point in time. If it is a little, or even a lot out, the mobile Hab simply changes course to suit.

As new parts and tools for repair are sent with each cargo vehicle, the reliability of the Habs mobility systems would be maintained. In the unfortunate event that the mobility system fails unrepairably, the next cargo vehicle can send a replacement system, which by design is capable of transporting itself to the Hab for fitting.

If this fails, there may still be a light rover onboard the Hab which, either manned or remotely operated, can be used to collect the mobility system. If the new mobility system still fails, the crew of the stranded Hab could utilize the rover to collect supplies from the cargo vehicle (as in other architectures) until another cargo vehicle, with another mobility system, is sent. However, there should be enough supplies contained in the Hab itself to last many years.

I can imagine that a (very unlikely) permanent stranding event would serve to accelerate ERV development if it has not been finished already. In any case, the crew would simply wait it out on the surface, being continuosly re-supplied by cargo deliveries, until the ERV arrives.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

If the targeting/landing systems are well enough developed, I can imagine that the cargo vehicles will be landed at pre-selected sites of scientific interest, of which the Hab will already be pre-stationed. This way, the cargo vehicle can be used as a spacious, but discardable lab (remembering that the mobile hab can be driven right up next to the cargo vehicle, and the two can be docked directly together). Actually, advanced targeting systems might not be required, as the Hab would serve as a langing beacon / guidance system.

Discussion of the mobile hab concept appears here Combining the Rover and Hab - Go RV'ing! and here Has the importance of mobility been under-rated

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

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From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Sorry cIclops. Sometimes, I can be a bit of a dick. I must have misunderstood your proposal.

Nevertheless, I think that I have made the point that this proposal differs enough from similar previous proposals. The integration of Hab mobility is one key point.

I think your proposal touched on some degree of reliance on base-building. I have the view that base-building should only be attempted after the planet has been thoroughly explored, and a suitably rich location found.

Remember, Mars is a planet, not an island. It is unimaginably vast. With that said, I fear that any foray into pre-mature base building would only pull resources away from the explorers further out.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

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From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Now it needs a name...

How about the (rather generic but suitable) 'Manned Exploration of Mars' architecture, or 'MXM' for short?

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Here's what the development schedule might look like:

1. Development of Descent system allows Cargo delivery. First flights are to deliver cargo to a single landing site for future occupation.

2. Development of Life support system allows Habitat. First flights send crew to location of pre-delivered supplies.

3. Development of Mobility system allows Mobile Habitat. Mobility cradle is sent with cargo. Crew bolt it to their habitat to allow long-range mobility.

4. Development of advanced ISRU system allows large scale surface fuel production. By this time, smaller ISRU systems have been tested as part of previous cargo flights.

5. Development of Mars Ascent stage allows Earth Return Vehicle. Again, smaller ascent stages have been tested as part of earlier cargo flights. The full scale ISRU system (with hydrogen feedstock) may be sent seperately to the ERV.

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Perhaps the best part of the MXM architecture is that it allows the more complicated technologies (mobility system, ISRU, ascent stage) to be developed and tested on the martian surface, as part of the cargo deliveries. As the cargo vehicles are delivered accurately to the Hab (thanks to landing beacons, as the mobile Hab should be waiting at a good science spot), these technologies can be tested as part of the crews science objectives.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Actually, it might be better to use the DRM architecture for the return leg...

As the surface stay is so long (5 or 10 years), the one extra HLLV launch required using DRM becomes trivial.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Let me summarize my proposal from a different perspective:

First launch window (Testing & Preparation): Cargo vehicles and uncrewed (spare) Hab sent to various sites. These serve as landing beacons for future missions.

Second launch window (Manned Landings): A few crewed Habs are sent to these sites. Previously landed vehicles contain spares, supplies, and science equipment.

Third launch window (Capabilities Expanded): Surface mobilities are enhanced with cargo deliveries of necessary equipment. Small ISRU plants are also tested on the surface.

Fourth launch window (Supply Mission): After having roamed the surface, the mobile habs pick a good location for a temporary base. Additional cargo missions are delivered here for supply of science equipment and re-supply of consumables in order to extend the mission duration.

Fifth launch window (Supply Mission): Again, the mobile hab would have moved on to find another interesting spot. Another cargo vehicle is sent to the site as before.

Sixth launch window (ERV Delivery): The technologies necessary for the ERV would have been thoroughly trialed up until this point (as part of earlier cargo missions). The completed ERV is sent to the location of the Hab as before.

Seventh launch window (Return to Earth): The astronauts, having explored a vast amount of martian terrain, are given the opportunity to return to the Earth. They could either use a two-step approach (a la DRM), with a seperate Ascent and ERV vehicle, or a one-step approach (a la Mars Direct), with a do-it-all ERV.

In the above scenario, the mission duration is about 10 or 12 years, but this depends only on when the ERV is completed. If ERV development is accelerated, a mission duration of only 4 years is possible using this architecture.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Marsdrive Mission Design

Not a bad list of timetable progression IMO

There are a few more sites working on simular plans, such as the 9 ton at a time over on the space.com forum

The main problem is still accuracy and down mass to surface for mars landings.

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Landing accuracy would not be a concern, as this architecture would have landing beacons to assists every landing (except for the first cargo missions, which would not need to be precission landed anyhow).

Why is down-mass a problem?

I can imagine huge pieces of science equipment delivered with each cargo flight, along with many spares, and supplies to last years...

Originally, I focused on the 'mobile hab' part of the design. But the idea of progressive mission development (by delaying the ERV) is interesting in itself. However, both concepts, by themselves, have their problems. It is when the two concepts are combined that everything starts to fall into place.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

SpaceNut

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From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Marsdrive Mission Design

The current down mass capability from orbit of a craft in the 12 mt is about 2 mt while the planned MSL is going to be in the 15 mt in orbit with landing about 6 mt to the surface.

Due to thin atmospher and size of heat shield that is about as good as we are going to get.

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

I see what you're saying. If that be the case, then all manned mission designs would share this problem.

Surely though, landing a single 24-tonne tonne spacecraft is the equivalent to landing four 6-tonne spacecraft in parallel?

Are there any papers written on the mass-capture capability of the martian atmosphere?

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Marsdrive Mission Design

Enteiring Mars orbit after the 6 months journey and oposing methods to do so....

http://en.wikipedia.org/wiki/Aerobraking

Aerobraking can be used to reduce fuel requirements by using a smaller burn to allow the spacecraft to be captured into a very elongated elliptic orbit. Aerobraking is then used to circularize the orbit. Due to the small effect of atmospheric drag, achieving the final orbit takes a long time (e.g., over 6 months when arriving at Mars), and may require several hundred passes through the atmosphere of the planet or moon.

I do no think we can wait that long before descending to the surface IMO.

Aerocapture is a related but more extreme method in which no initial orbit-injection burn is performed. Instead, the spacecraft plunges deeply into the atmosphere without an initial insertion burn, and emerges from this single pass in the atmosphere with an apoapsis near that of the desired orbit.

How are burns done if there is a heatshield for each atmospheric plunge?

http://ccar.colorado.edu/asen5050/proje … 2004/dunn/
This has the aerobraking table for comparison of Magellan and MGS.
You will also find the ballute design concept for Aerocapture.

The Aerobraking and Impact Attenuation: http://www.tsgc.utexas.edu/archive/subsystems/aero.pdf
Lots of equations in this document....

Ok now that the descriptions are available the unknown is that we do not know what is going to the surface so how can we know what was pushed from earth to get to this point that will be slowed to circularize in as short a period of time as possible. Also the longer the ship is the greater the chances are for it to breakup while entering into the atmosphere..

This may look off topic but when the atmospheres contents change so does the drag rate....

Rovers begin new observations on changing Martian atmosphere

the APXS instruments aboard NASA's twin Mars rovers, Spirit and Opportunity, had recorded fluctuations in the argon composition of the Martian atmosphere. "The amount of argon in the atmosphere is changing constantly

During warmer seasons, approximately 95 percent of the Martian atmosphere consists of carbon dioxide. Nitrogen accounts for almost 3 percent and argon for less than 2 percent. But when winter sets in at one of the poles, carbon dioxide freezes out of the atmosphere to form a polar cap, causing a low-pressure system that moves air toward the pole.

Argon stays in the atmosphere and becomes enhanced because it freezes at a much lower temperature, Economou said. An instrument on NASA's Odyssey orbiter around Mars found that on the Mars south pole during the winter, the argon concentration is six times higher than during the warmer seasons.

"The amount of argon that comes with the air mass stays in the atmosphere," he explained. "Carbon dioxide drops, so the ratio of argon to carbon dioxide is increasing constantly until the next season."

http://www.universetoday.com/2007/07/17 … ed-planet/

Mars' atmosphere is only one per cent as dense as Earth's. For comparison, Mars atmosphere at its thickest is equivalent to Earth's atmosphere at about 35 kilometers above the surface The air is so thin that a heavy vehicle like a CEV will basically plummet to the surface; there's not enough air resistance to slow it down sufficiently. Parachutes can only be opened at speeds less than Mach 2, and a heavy spacecraft on Mars would never go that slow by using just a heat shield. "And there are no parachutes that you could use to slow this vehicle down,? said Manning.

Using thrusters in combination with a heat shield and parachute also poses challenges. Assuming the vehicle has used some technique to slow to under Mach 1, using propulsion just in last stages of descent to gradually adjust the lander's trajectory would enable the vehicle to arrive very precisely at the desired landing site. "We're looking at firing thrusters less than 1 kilometer above the ground. Your parachute has been discarded, and you see that you are perhaps 5 kilometers south of where you want to land," said Manning

The best hope on the horizon for making the human enterprise on Mars possible is a new type of supersonic decelerator that's only on the drawing board. A few companies are developing a new inflatable supersonic decelerator called a Hypercone.

Imagine a huge donut with a skin across its surface that girdles the vehicle and inflates very quickly with gas rockets (like air bags) to create a conical shape. This would inflate about 10 kilometers above the ground while the vehicle is traveling at Mach 4 or 5, after peak heating. The Hypercone would act as an aerodynamic anchor to slow the vehicle to Mach 1

I am just going to add a lot of links as they relate to entering the Mars Atmosphere and trying to slow down.

Though this is a Beginner's Guide to Kites site of Glenn Research it will start the process of learning.
http://www.grc.nasa.gov/WWW/K-12/airplane/shortk.html

You will find the Mars Atmosphere model equation from the link http://www.grc.nasa.gov/WWW/K-12/airplane/atmosmre.html for imperial and metric terms available.

Where temperature plays a large role in what happens....

In order to follow up on where to start you need to understand the launch to orbit and burn to start the journey. To escape the Earth’s gravity, a vehicle must attain a velocity of about 11.2 km/s. Mars’ escape velocity is 5.0 km/s.  The additional velocity needed to enter a Hohmann transfer orbit back to Earth is 2.6 km/s.

The Human Exploration of Mars

In order to minimize this additional velocity, the vehicle can enter an elliptical orbit known as a Hohmann transfer orbit, and the journey can be timed to arrive at Mars when it is closest to the Sun (perihelion).  The additional velocity needed to reach Mars when it is at perihelion, 1.38 AU from the Sun, is 2.3 km/s.  (1 AU, or astronomical unit, is the average distance from the Earth to the Sun.)  However, if the vehicle leaves Earth at a velocity of about 11.4 km/s, or just 0.2 km/s above escape velocity, it will retain the necessary velocity of 2.3 km/s when it is far from Earth.

A history of the past flights and
Landing on Mars

Of course every flight takes the risk of failure in stride with success as
Mars Probes Take On Tough Challenges

Langley engineers are studying different spacecraft shapes, called aeroshells, capable of "aero-maneuvering" at Mars. The hope is to shrink a Mars landing zone from the usual 62-mile to 124-mile (100-kilometer to 200-kilometer) footprint down to a mere 2 miles (3 kilometers). It would be the most unique Mars entry ever attempted, Lockwood said.

So what are the options then to land
Bugs on Mars; Unearthly aircraft may explore the Red Planet and beyond

The idea of using flapping-wing vehicles came later to him and his colleagues, almost as an afterthought, given what they knew already about aerodynamics and the Martian atmosphere. The alien air is so thin roughly equivalent to Earth's atmosphere at 30,000 meters that a fixed-wing plane would have to fly faster than 400 kilometers per hour (km/h) to avoid crashing. Below that speed, it wouldn't be able to generate enough lift to stay airborne. For comparison, 400 km/h is about the top speed of a single engine, four-passenger plane traveling in Earth's skies.

Sounds wierder than fiction but so are lots of even worse ideas.

Cassanova says that flapping-wing and rotorcraft fliers that could work in Martian skies look like they'll be ready for action in about 10 years rather than 40. Moreover, he predicts, "there are going to be some breakthroughs here in understanding the aerodynamics of flapping wings and very small rotary blades," advances that could change the character of Earth's own flying fleets

This image reminds me of some in a thread on newmars of airplanes for mars...

Just seems that the farther we would wish to not use references from MS the more we find he has numbers for. This particular on has the mass to energy for powering rovers and more.
Methods for Achieving Long Range Mobility on Mars

http://en.wikipedia.org/wiki/Atmospheric_reentry

http://www.4frontierscorp.com/dev/asset … rs_EDL.pdf
Mars Exploration Entry, Descent and Landing Challenges1,2

Robert D. Braun
Georgia Institute of Technology
Atlanta, GA 30332-0150

Robert M. Manning
Jet Propulsion Laboratory
California Institute of Technology

I think you may have seen something simular to this means to slow a craft on entry.

Aerobrakes & Ballutes

Not much on the page so will just copy here:

Program Details:

ILC/LMA Study of ballute configurations, materials and construction
Tucked back ballute design
300 second operation duration
Max dynamic pressure 1.18psi
Internal pressure of 2.4 psi (320 lb/in stress in conical section)
Smooth interface to aeroshell through joint design
Zylon 2000 selected, 2300lb/in 23x23 plain weave coated with LT-50 silicone
TPS - 2 outer layers of Nextel 312 and 1 inner layer of Fiberfrax ceramic felt

I think the tps outer layers are simular if not the same as used on the shuttle for blankets and gap fillers.

ENTRY, DESCENT, AND LANDING CHALLENGES OF HUMAN MARS EXPLORATION
http://www.ae.gatech.edu/labs/ssdl/Pape … 0FINAL.pdf

Tons on documents here
http://www.ssdl.gatech.edu/TechPapers.htm

noosfractal

Member

From: Biosphere 1

Registered: 2005-10-04

Posts: 824

Website

Re: Marsdrive Mission Design

Aerocapture is a related but more extreme method in which no initial orbit-injection burn is performed. Instead, the spacecraft plunges deeply into the atmosphere without an initial insertion burn, and emerges from this single pass in the atmosphere with an apoapsis near that of the desired orbit.

How are burns done if there is a heatshield for each atmospheric plunge?

The idea is that there is a single plunge and then you are in orbit ...

http://en.wikipedia.org/wiki/Aerocapture

That's why it is so much harder - you dissipate all that energy in just one pass.  Apparently you need perpendicular thrusters for altitude control. 

You also need a deorbit burn + heatshield, but that is a very different (and much easier) problem.

Just seems that the farther we would wish to not use references from MS the more we find he has numbers for.

Zubrin is a bona fide genius.  There is hostility towards him because he makes even very bright people seem average by comparison.  People need to get over themselves and take advantage of the work he's done.

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Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Marsdrive Mission Design

Thanks for all that info SpaceNut. You're a legend mate.

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- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]