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Entrespace Interplanetary Co-op

Posted by: rpspeck - Sat Feb 03, 2007 12:48 am
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Entrespace Interplanetary Co-op 
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Post Entrespace Interplanetary Co-op   Posted on: Sat Feb 03, 2007 12:48 am
See notes in last paragraph.

This topic, rather than Announcements, will be used for feedback and discussion of this effort.

Micro-Space, and its nonprofit affiliate, Entrespace, are looking for qualified volunteers to review the “Entrespace Interplanetary Co-opâ€


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Post Delta V Range   Posted on: Sat Feb 03, 2007 2:09 am
Note correction to Mars aerobraking and return Delta V > 700 m/sec)
The V(infinity) at Mars is modestly less than at the Earth, but Mars' lower escape velocity cuts the gravity boost factor to less than half. I copied the wrong figure from my notes.

The Caltech table supplied in the announcements topic is encouraging, but does fold an allowance for plane change into its numbers. I say encouraging, because the claim that "it's very hard to go to Mars" has been hammered into discussions for so many years that computing modest delta V numbers makes one doubt either his analysis or his sanity!

As shown in that table, it is easier to land on Mars than it is to reach geosynchronous orbit or Low Lunar Orbit, let alone to land on the Moon. The round trip to Mars’ surface is only modestly more difficult than a round trip to the Lunar surface (requiring about a 2:1 additional mass ratio with a good storable propellant (2.4 km/s)). A round trip to either of Mars’ moons or low Mars orbit requires considerably less spacecraft performance than the Apollo Moon landings!

The key to mars exploration is thus NOT spacecraft performance! It is first, good life support systems, and second high reliability. Given reasonable life support systems, the crew adds to the operational reliability. Robotic missions may be tempting, but the ISS is not expected to run for even a month without continued human maintenance work. If interplanetary exploration is appraised with a “social significanceâ€


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Post    Posted on: Sat Feb 03, 2007 5:44 pm
It is easy for me to imagine a transfer orbit to Mars that makes the plane change at the moment it leaves Earth, but I don't know if that costs more or less deltaV than a mid course correction would. It wouldn arrive crossing the plane of Mars' orbit at some angle other than 0, but the gravity of Mars should take care of that at no deltaV cost when you enter orbit.


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Post    Posted on: Sat Feb 03, 2007 10:01 pm
G'day,

Water is going to be your main lifesupprt requirement. So if you can minimise the water requirment your chances of success will increase. Laundry uses water so avoiding laundry is a good idea. Have a read of this:

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


Self-clean technology to remove the mud, sweat and tears of wash day for ever

By Richard Gray, Science Correspondent, Sunday Telegraph
Last Updated: 11:44pm GMT 30/12/2006

Muddy sports kit, the bane of parents with active children, may be heading for the laundry basket of history.

Scientists have produced a coating that could make filthy rugby shirts and grubby football shorts a thing of the past.
Slef-cleaning sportswear

The "self-cleaning" process makes fabrics repel water, resist stains and even kill off the bacteria that grow in sweat and make clothes smell. As a result, kit could be worn repeatedly between washes, the distinctive aroma of kit bags gone for ever – even performance on the field could be enhanced.

Scientists working for the US Air Force have already produced T-shirts and underwear that can be worn for weeks at a time without washing, and the technology has now been licensed to a London company, Alexium, to develop for civilian applications.

"We are expecting sportswear to be one of the biggest areas where this technology will be used," said John Almond, a director with Alexium. "We can treat almost any surface to take on a range of different properties that work side by side.

"We are now talking to some major sportswear brands to use this technology, but there are hundreds of other applications we are investigating, from hospital bedding and nurses' uniforms to air conditioning filters on planes and cruise ships."
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Sports kits could be in the shops within a year from an agreement being signed, and would add only "a few pounds" to the cost, Mr Almond said.

While it will not quite make the washing machine redundant, treated clothing needs to be washed far less often and is easier to clean when finally laundered.

Details of the technology have been welcomed by athletes. Gary Malmstrom, manager of the London Marathon Store, said that it could help make clothing more comfortable during a marathon. "Anything that can make running 26.2 miles that little bit more comfortable is great news for marathon runners," he said.

The American military developed the new coating in a £14 million research programme over five years. It was initially intended to turn soldiers' ordinary battle dress uniforms into kit that could offer protection in biological warfare. Tests found that the process could kill anthrax and other bacteria used as weapons. Soldiers have also tested treated underwear, wearing garments for several weeks in combat simulations.

Jeff Owens, the scientist at the US Air Force who developed the technology, said: "During Desert Storm most casualties were from bacterial infections rather than from accidents or friendly fire. We have treated T-shirts and underwear for soldiers who tested them for several weeks and found that they remained hygienic as the clothing was actively killing the bacteria. They also helped clear up some skin complaints in those testing them."

The technology uses microwaves to fix microscopic nanoparticles permanently to the fibres of clothing. These nanoparticles can then have a range of chemical properties attached to them to produce a surface impenetrable to water and able to kill bacteria.

Over time, the effectiveness of the coating falls as the active chemicals are knocked off, but the scientists claim it can be restored by soaking the material in a fresh solution of the same chemicals.

Ottilia Saxl, the chief executive of the leading information provider in the field, the Institute of Nanotechnology, in Stirling, said that the treatment could have far wider uses.

"This technology could have many applications, -not just in the leisure industry. The anti-bacterial properties could be of great use for chefs in kitchens and in hospitals where antibiotic resistance is a big problem."


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Post The Space Grand Slam, Solo.   Posted on: Sun Feb 04, 2007 7:32 am
G'day All,

There is a type of mission that would be very suitable for solo adventurer missions.. That is flyby missions. Flyby missions were researched seriously in the 1960's but were eventually dismissed as robotic space probes appeared to make them redundant.

However, put the science aside for a moment. Having a even a single human in the spacecraft changes the flight from a mission to an expedition. It becomes an adventure, and bringing the adventure of space exploration to Earth would be an enormous contribution to space development. What it can do is integrate the reality of space into our consciousness, helps make it real. To fully understand how important this is have a listen to David Beaver on the Space Show .

http://www.thespaceshow.com/detail.asp?q=653

Now there is a type of flyby expedition that would be ideal for an adventurer, The Grand Slam, a flyby mission of Earth, Mars and Venus. Gen. Gaetano Arturo Crocco showed back in the 1950's that such a mission could be done with virtually no requirement for propellant after leaving Earth, the spaceship uses the planet's gravity to change its course. Further more, depending on the launch window, the expedition can be completed in a year. Well within our experience of microgravity.

See http://www.tdf.it/2006/2/crocco_en.htm

The explorer takes with him/her a couple of high definition zoom cameras and theres a web cam in the spacecraft. Some relativity low resolution images are sent back to Earth while in flight but on the return gigabytes of raw information is provided to film makers to make an amazing movie (3D IMAX?) . We get to see Mars Venus Earth and their satellites close up. Maybe even a passing comet or asteroid as well. Importantly we see the explorers trials and tribulations to coping with the mission. We see their reaction to seeing the three main inner system planets. Frank White has written about the Overview Effect, this would be the Overview Effect 3X, shareable with humanity.

As to science, well being close to the target planet will allow the explorer to operate surface vehicles without the time delay problem. Perhaps a sample return mission could be integrated into the flyby.

ta

Ralph


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Post    Posted on: Mon Feb 05, 2007 5:54 pm
campbelp2002 wrote:
It is easy for me to imagine a transfer orbit to Mars that makes the plane change at the moment it leaves Earth ...


It is much easier to accomplish small accelerations by combining them with large accelerations (the delta V “costâ€


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Post    Posted on: Mon Feb 05, 2007 7:02 pm
ralphbuttigieg wrote:
G'day,
Laundry uses water so avoiding laundry is a good idea.


Interesting reference. Thanks. My personal concept combines mountaineering experience with the fact that there is little “dirtâ€


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Post    Posted on: Mon Feb 05, 2007 10:27 pm
rpspeck wrote:
a low energy (Hohmann) transfer ends up exactly opposite the starting point on a line through the gravitational primary (Sun).
I knew that. :oops:
But I guess I didn't fully think it through. :oops:
However, by expending a little more energy at Earth departure you could enter an orbit with an aphelion slightly beyond Mars, and so have two different places in Mars' orbit where an intercept could take place. Then a tilted plane that did pass through the Sun, plus the Earth at departure and Mars at arrival is possible. Depending the on the exact geometry of the situation, could that result in less total deltaV than a classic Hohmann orbit with a kink in the middle? I suppose the answer would be in how NASA actually does it. They have really talented people who come up with almost magical trajectories to make the most out of limited deltaV.


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Post Eureka !   Posted on: Tue Feb 06, 2007 8:34 pm
I agree that a greater transfer velocity would create two intercept points displaced from the 180 degree (Sin a = 0) point so that an initial plane change impulse would produce a residual displacement at intercept. Thanks for reminding me of this! It might work very well, since even a small aphelion increase would create significant offsets for the intercept “true anomalyâ€


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