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Deep Space Hardware (MARS)

Posted by: rpspeck - Tue Mar 22, 2005 4:57 am
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Deep Space Hardware (MARS) 
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Post    Posted on: Fri Apr 21, 2006 6:05 pm
ralphbuttigieg wrote:
G'day,

This effort to develop a reliable life support system is well and good but are you planning to have a storm cellar in case of solar flares on a Mars trip?


I am definitely planning to have a solar storm cellar. Yet since this radiation is directional and only modest energy, it won’t take much systems mass (or food) for adequate shielding. The hard cosmic radiation is almost impossible to shield, but best estimates put the risk below the (not inconsequential) level accepted by those who choose to smoke. I choose to accept other risks. For anyone who doesn’t know it – very little cosmic radiation ACTIVATES materials used for shielding. Eating or drinking your shield when you no longer expect to need it is no problem at all.


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Post    Posted on: Fri Apr 21, 2006 9:16 pm
rpspeck wrote:

I am definitely planning to have a solar storm cellar. Yet since this radiation is directional and only modest energy, it won’t take much systems mass (or food) for adequate shielding. The hard cosmic radiation is almost impossible to shield, but best estimates put the risk below the (not inconsequential) level accepted by those who choose to smoke. I choose to accept other risks. For anyone who doesn’t know it – very little cosmic radiation ACTIVATES materials used for shielding. Eating or drinking your shield when you no longer expect to need it is no problem at all.


G'day,

A lightweight plastic spaceship is an advantage here. It minimises the secondary radiation effects from cosmic rays. But I'm not sure a spacecraft with a total mass of under 2 tonnes will provide and adequate storm shelter.

What about artificial gravity? You seem to be designing the equipment to operate in zero-G but thats just not good enough for a long space mission esprcially if you expect the astronaut to do real work on Mars. It would be a relatively simple matter to spin the spacecraft using the spent fuel tanks as counter weights.

ta

Ralph


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Post    Posted on: Sat Apr 22, 2006 4:56 pm
I am optimistic that my Gravity Sim-Suit (see my Public Domain Technology thread) will sustain muscle and bone condition without complicating communications and optical trajectory monitoring as spin would. The Gravity Sim-Suit idea recognizes what Orthodontists know – that bone condition in particular responds to sustained forces much better than to periodic forces. Elastic bands built into clothing could produce near normal stresses on the major bones even while at rest or sleeping.

I also assume that very motivated individuals will be involved in early flights, and that regular workouts with very lightweight elastic exercise bands will sustain muscle tone without superimposing centrifugal forces to produce automatic exercise. I am not outlining a system for tourists or lazy individuals: I am outlining systems the adventurous will use to become the first to reach new planets! I can’t conceive of the dedication necessary to win Olympic Gold, but obviously hundreds make that effort and have a shot at such victories. That kind of effort will make lightweight equipment suffice.

Actual analysis of Solar Flare exposure levels predict that even the thin walls of the LEM reduce radiation exposure by an order of magnitude and make severe events survivable. Given the directional character of this radiation, a one meter disk would suffice for shielding if it, and the astronaut standing over it, can be properly aligned. One gram per square centimeter (10 kg of food, water or hardware for a 110 cm diameter disk) provides much better shielding. This does not address the ultimate – bigger than any previously recorded – event and worst case complications. But in mountain climbing, for example, an unlikely rock or avalanche, even after care to minimize the chances, can still kill you – but we accept that risk and go.


Note regarding the ‘partial pressure’ spacesuits: various efforts have been made with related ‘counter pressure’ space suits using various types of bands, wraps and other systems. However my point is not an insistence on doing away with a pressure envelope, but that a cut or rip in such an envelope may not be fatal or even serious with a well designed system. In recent history, one spacesuit cut would be fatal. A similar point existed – and is now ancient history – with diving equipment. Soon, such catastrophic failure modes will be ancient history with spacesuits.

I have pointed out earlier that the Gamow Bag is a sufficient 15 pound orbital habitat. Even the stock, 2 psi pressurization, is 2.5 times the atmospheric pressure used to demonstrate the F-22 partial pressure suit, and nearly enough to use for simple Oxygen breathing. A well designed, body fitted nylon or Kevlar pressure suit should be much lighter. The zero pressure approach allows survival even if this envelope is breached.


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Post    Posted on: Sun Apr 23, 2006 1:30 am
G'day Richard,

From your space review article and website I understand that the Micro-Space spacesuit is a partial pressure suit similar to the one te F-22 fighter pilots use with a low pressure SCUBA type mouthpiece for breathing with a full face pressurised helmet over that. Is this correct? How light weight do you expect the suit to be?

ta

Ralph


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Post    Posted on: Tue Apr 25, 2006 1:53 am
The Micro-Space suits are planned in two forms. The first is a test flight suit, which will perfect systems for later actual space use. This version MUST provide protection from Methanol fires (which aren’t particularly hot), chemical exposure and rocket exhaust fumes, plus boiling water, firefighting water deluge, fire fighting CO2 flood, and sea water immersion, with enough respirator time (more than an hour) so that flight, preparation and all of the above events can be handled without panic. This suit will be used (with a parachute) for moderate altitude human flight tests. Excellent voice communication plus medical monitors will be included.

We don’t have years of testing high altitude aircraft cabin designs – as Scaled does – and do not expect to borrow pressure suits from Edwards AFB - as Scaled did for testing their Proteus cabin systems (which are very much like the White Knight and SS1). Others may think they can skip these steps and the pressure suits logically required if “Foolproofâ€


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Post    Posted on: Tue Apr 25, 2006 7:49 am
G'day Richard,

You might be interested in the following:

"Speaking of prizes, Brant Sponberg of NASA’s Centennial Challenges program talked about several other prizes either in progress or under development. One of particular interest for the personal spaceflight community is a low-cost space pressure suit. The notional prize amount for this is $1 million, and the rules are still under development."

http://www.personalspaceflight.info/2006/04/23/

Also theres an Australian attempt to test a bio-regenerate life support system in a underwater habitat this year.

http://www.biosub.com.au/

ta

Ralph


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Post Pure Oxygen enviroment   Posted on: Thu Apr 27, 2006 1:08 pm
G'day,

Theres been some discussion about the advisability of a low pressure pure oxygen enviroment for a long space mission. NASA did some research into this back into the 60's. They tested subjects for up to 30 days with only minor
problems. Richard is going to have to test it for longer periods but it looks like a goer.

ta

Ralph

*********************************

See: http://history.nasa.gov/SP-368/s2ch5.htm

Subsequent atmosphere validation tests up to thirty days in duration indicated that the 100 percent oxygen, 34 500 N/m2 (5 psia) atmosphere was physiologically adequate (Herlocher, 1964; Robertson et al., 1964; Zalusky, et al., 1964). These studies clearly indicated, however, that this atmosphere was associated with nuisance findings such as aural atelectasis, eye irritation, and nasal congestion. Medical investigations associated with Gemini manned space flights resulted in suggestive, but not conclusive, evidence of hematologic changes resulting from exposure to a single gas atmosphere (Fischer et al., 1967). A consistent, time-related decrease in red cell mass was observed (Richardson et al., 1972). Although the causes and implications of this decrease in red cell mass were not completely understood they were not considered to be a deterrent to the use of 100 percent oxygen at 34 500 N/m2 (5 psia) for Apollo spacecraft because of the limited duration of these missions.


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Post Re: Pure Oxygen enviroment   Posted on: Thu Apr 27, 2006 2:52 pm

:) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :)
Three cheers for Ralph!
I have been looking for something like that for quite some time now!


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Post    Posted on: Thu Apr 27, 2006 4:02 pm
Thanks for the info! I agree that this is exactly the information I have been hoping to find.

Note for reference that with CPR, the victim's inspired CO2 level is over 30 mm of mercury (twice the NASA "Emergency" level), yet saves a great many lives. This serves as a notification that NASA's figures (and conclusions) are more cautious than their wording may indicate. My own short time tests indicate that 76 mm Hg, 10% of sea level air is extremely stressful and is probably above a real life threatening emergency level.

My 1958 “Handbook of Respirationâ€


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Post Mass Breakdown   Posted on: Sat May 20, 2006 10:01 pm
G'day,

I throw this in for general discussion. Below is the mass breakdown of the well known Zubrin Mars Direct proposal. Can we go through each item and reduce the mass for an ultralight mission? Resonable justification needs to be provided.

*********************

Habitat Mass Breakdown - total 25,200 kg landed on Martian surface:

* Habitat structure: 5,000
* Life support system: 3,000
* Consumables: 7,000
* Solar array (5 kWe): 1,000
* Reaction control system: 500
* Communications and information management: 200
* Furnishings: 1,000
* 4 space suits: 400
* Spares and 16% growth: 3,500
* Pressurized rover: 1,400
* 2 Open rovers: 800
* Lab equipment: 500
* Field science equipment: 500
* Crew: 4

**************

Few thoughs from me.

I'm asuming a one-two person mission. The size of habitat 3m dia by 5 high. Two levels, one for the crew the other for most of the equipment , airlock, consumables etc.

Hab structure: 300kg. This is based on the old LLNL inflatable design.

comms and information. 20kg. Modern day mountain and polar explorers
take a satphone, PDA and digital camera. Less the 1kg mass. If we allow 2kgs for the electronics thats leaves the rest for the sat dish. A 1.2 meter aluminium dish weights about 16 kg. Considering the dish would properly be ultralight carbon fiber the 20kg should cover it.

I'm especially interested in what people think the power requirements would be.

ta

Ralph


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Post    Posted on: Sun May 21, 2006 9:25 am
I think that while reducing the crew obviously reduces the mass requirement, a larger crew is almost essential for such a long duration mission.

Ignoring the social issues of 2 people being couped up together for such a long time, there is also safety to be considered.

The 2 astronauts on the ISS spend most of their time looking after the station and doing maintenance, a Mars habitat is also likely to be labour intensive due to the dust and environmental conditions. Added to that the need to produce food and do trips outside, probably on a daily basis, would make a 2 man crew impossible.

Also if the object is to set up a permanent base rather than do an Apollo like hit and run then the extra man-power will be needed to build up infrastructure on the surface and enable a wider range of skills and experience to be drawn on.

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Post    Posted on: Sun May 21, 2006 11:18 am
G'day,

As I write this there are adventurers sailing around the world solo, a journey that can take a year, Raphaela le Gouvello is windsurfing the Indian ocean, Italian Alex Bellini is recovering from having spent 225 days rowing the Atlantic solo. Numerous small teams have trekked the Arctic and Antarctic climbed great mountains etc. A New Zealander a few days ago became the first person to climb Mt Everest without legs! Yep, these explorers take calculated risk and the death rate from climbing Everest is 5-10% but people still do it.

This website should be a must read for any student of exploration http://www.explorersweb.com/index.html

Remember the ISS is BIG! The old salyut space stations only had 2 people.

As to what can a couple of people do on Mars... Two people can do more in two weeks on Mars then the two rovers have done in two years.

Even a one person flyby can do useful science. Have the explorer operate
robots on the surface as the space yacht approachs then have him rendezvous with a return sample capsule.

ta

Ralph

Andy Hill wrote:
I think that while reducing the crew obviously reduces the mass requirement, a larger crew is almost essential for such a long duration mission.

.


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Post    Posted on: Sun May 21, 2006 2:36 pm
Hello Ralph

While you are of course correct that people do solo achievements all the time, it is also true to say that in nearly every case the feat being undertaken has been done by a team first. Solo yachtmen are following well known routes where if they get into trouble they can normally be rescued in a matter of days if not hours. The perils of Everest were conquered by a team of climbers initially and I suspect that a lot of the danger has been removed by the development of better equipment and previous experience gained on similar climbs. No such analog exists for Mars so I dont see how you can compare the 2.

Crossing the atlantic singlehanded is an awesome feat but does not really further our knowledge or achieve a goal that might change humanity, IMO it is on a different scale entirely to a Mars mission with a different objective. In the examples you give the objective is the feat itself, while for a Mars mission the trip is only half the story. Your solo yachtman would also have to be a specialist farmer, a boat/vehicle repair man and a geologist, not to mention have sufficient medical knowledge/skill to recognise health problems (some of which are likely to be pretty specialised in space) to even get close.

I see no reason to send a foot print in the sand mission to Mars so that humanity can say they did it. Exploration will require a mix of people with different skills, one or two people will not be able to achieve a full analysis of their surroundings. I would agree that a single person would achieve much more than a multitude of rovers and orbiters but not as much as a team. If we are going to go to Mars lets do it properly and not with half measures.

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Post    Posted on: Mon May 22, 2006 7:11 am
Hello, Andy Hill,

there might be ways to experiment near Earth and then do it with smaller numbers of people.

For example there could be a vehicle permanently flying from Earth to the Moon and back. The vehicle never lands for 9 months and the life aboard that vehicle is as if it were going for Mars - this way a trip to Mars could be simulated while being in space really. This would be similar to the situation of adventures on Earth who allways could be rescued in case of emergency.

Since a lot is known about the environmental conditions on Mars already such an environment could be created artificially on Earth (or later on Moon to involve the radiation etc.) and a crew could live in it for a couple of months.

This might enable to reduce the number of crewmen.

What about it?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


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Post    Posted on: Mon May 22, 2006 7:38 am
Hello Ekkehard

I think that is one of the main reasons for going to the Moon first, to improve technology and try out new systems.

Sending a craft orbiting around the Moon and Earth would cost as much as sending a bigger mission to Mars, cause a further delay in getting there and is unnecessary since we have the ISS or possibly a Bigelow floatel in a few years.

I think it would be a good idea to create a sealed Mars environment on Earth to test equipment. Something like a large low pressure CO2 filled box with the same arid dusty conditions as Mars would be very useful. You could run long term missions inside like the Mars society does at the moment but use the actual equipment rather than mock-ups.

All this is beside the point though, the main reasons for sending more people IMO is to get a wider range of experience and improve social relations.

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