Alpha Centauri Explorer

[spacester]

[positive feedback]<br /><font color="yellow">Sound like a good solution to you ? </font><br /><br />Yes it does. It is a fine plan <br /><br />Mine is a little different, but so what? If it works out more like your way than like my way, I'll still be thrilled.<br />[/positive feedback] <div class="Discussion_UserSignature"> </div>

 

[vidar]

No_way<br /><br />Manned space bases on the Moon and on Mars are some long-term projects that probably will be realised. Mercury and Venus will not be settled due to the extreme temperatures. The moon Europa, which is frozen, has interesting properties that will be examined by unmanned probes. NEO, asteroids and comets are about to be explored. (Not to forget Titan.)<br /><br />The idea for ACE is not settlement. It is to get a communication-relay and an explorer-probe to the nearest star-system. This project can be done in parallel with exploring our own star-system.

 

[vidar]

Wouldn’t 100G destroy the equipment?

 

[vidar]

Could a Bussard ramjet do such collections nearby the Jovian planets instead?<br />The escape velocity will be far less. <br />Even the Oort cloud could provide some fuel. <br />

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>Mercury and Venus will not be settled due to the extreme temperatures.<p><hr /></p></p></blockquote><br />Wrong. Venus is basically a paradise planet at cloudtop levels (pressure, temperature, atmospheric composition and energy availability are all good ) , im sure there are lots of people who would like to live in floating cities.<br />Mercury has so much free solar energy available, and energy is the key for human activities. Excess energy allows you to get rid of the excess temperatures too. Mercury wont probably be settled per se but im predicting huge mining and industrial activities on the surface.<br /><br />Basically what im saying is : theres that huge solar system in front of us, to be discovered, tapped into and settled, i simply see no rush in visiting other stars.

 

[vidar]

Objects in the path, is certainly hazardous to such a journey. Objects larger than ‘fly on a windshield’ size must be avoided.<br /><br />I must admit that I do not know the exact location and distance to the star. However, all our planets and objects circle around the sun in a plane. But is the direction to Alpha Centauri straight trough that plane, or is the straight line between the stars in a different angle? If so, most objects are simply avoided and not hazardious. <br /><br />I certainly do not know how the Alpha Centauri objects are circling the star, but it is unlikely that ACE arrives in the worst thinkable plane.<br /><br />Most important, the ACE should bring a ‘black box’ to record and transmit on its path.

 

[tap_sa]

The farther the better but in any case you need to apply some thrust towards the sun to counter centrifugal force and maintain orbit.

 

[vidar]

This is what NASA say about Mercury and Venus.<br /><br />http://www.nasa.gov/worldbook/mercury_worldbook.html <br />‘Mercury is dry, extremely hot, and almost airless. The sun's rays are approximately seven times as strong on Mercury as they are on the Earth. The sun also appears about 2 1/2 times as large in Mercury's sky as in the Earth's.<br />Mercury does not have enough gases in its atmosphere to reduce the amount of heat and light it receives from the sun. The temperature on the planet may reach 840 degrees F (450 degrees C) during the day. But at night, the temperature may drop as low as -275 degrees F (-170 degrees C).’<br /><br />http://www.nasa.gov/worldbook/venus_worldbook.html<br />‘The surface of Venus is extremely hot and dry. There is no liquid water on the planet's surface because the high temperature would cause any liquid to boil away. Geologists have had difficulty learning about the surface of Venus because the planet is always surrounded by thick clouds of sulfuric acid.’<br /><br />I agree in exploring our own solar system. I think it is as important as exploring our own planet.<br />But I find it very unlikely to send manned missions to Venus or Mercury. These are no places for any human.<br />Anyway, this Topic is about an Alpha Centauri Explorer. Discussion about exploring our own solar system should continue under such a heading.<br />

 

[vidar]

Henryhallam<br /><br />Yes I see the problem with use of 100 tons initial mass, dry mass of 1 ton, 40 trillion degrees Celsius and 10000 gigawatts. Hopefully, there are more effective ways to put a nuclear rocket in motion. <br /><br />I was thinking more in the way of use of electromagnetism and gravity, or any other energy that is available in space. I am quite fascinated by the use of transforming electromagnetism into movement. That is done quite effective by the electromotor and in the magnetic levitation train, Maglev, which can reach over 400 km/h. Similar system could be interesting for launching rockets.<br /><br />I cannot think of a complete electronic, non-mechanic, way of propulsion. However, when accepting exploding chemical in a rocket chamber, it should be acceptable with a magnetic plate hammering in the rear of the rocket. That can be done by simply placing a magnet close to the backside, and an electromagnet behind the magnet that alternative shifting between + and – polarity. The magnet will then vibrate, i.e. alternative pushing the hull forward and getting back in place.<br /><br />However, I would like to see a solution completely electromagnetic like the Maglev solution.

 

[nexium]

We already have 4 probes enroute to the distant stars at about 50,000 miles per hour. Present technology might permit 100,000 miles per hour. Technology we might have in 2012 might produce a million miles per hour if we throw lots of money at several promising technologies. More likely we will not achieve one million miles per hour before 2050 due to our failure to spend billions on long shot technology. At an average speed of one million miles per hour it takes 27,000,000 hours to reach planets (if any) in the Centari triple system. The probability is near zero that any of the probe systems would be repairable or funtional after 27,000,000 hours. Odds are good the probe would miss the intended path by billions of miles due to parts failure, so there is no point in sending probes to the stars until we can go hundreds of times faster. Neil

 

[nexium]

450 degrees c is the highest temperature estimate I have seen for a record hot day on Mercury. Both poles of Mercury have crater bottoms where the sun's rays have not reached in thousands of years. These are cold and likely have a trace of water ice. If not the colonists can import water. These craters can not support large human populations, but a dozen humans may be easier than anywhere else in the solar system besides Earth. Advantages of Mercury polar colonies are constant low temperature. Seven times Earth's solar flux at the top of the crater wall 24/7. The best shielding from a super nova of any location in the solar system. Neil

 

[vidar]

Correct me if I am wrong.<br /><br />You are saying is that we can go at c/1000 today, but shouldn’t until we manage c/10.<br />

 

[vogon13]

3% lightspeed available now with sufficient payload to put a selfsustaining human colony on a hypothetical earth like planet in the centauri system.<br /><br />It's called Orion..... <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[gpurcell]

Ahem.<br /><br />We'll leave aside the technical insanity for a moment.<br /><br />Just think about this for a bit. A flyby of a star system at near c....how do you propose to do any meaningful analysis of anything! The odds are that any trajectory of your ray of light spaceship will be far enough from anything worthwhile that a large space observatory would be able to study the object in more detail, for a far longer period of time! Plus, you'll have to wait for years before your data returns to Earth!<br /><br />We won't be sending a probe to another star system unless there is a DARN good reason (e.g. clear signs of life) for several hundred years. That doesn't mean we won't know what is out there; I fully expect us to have a completed survey of our neighborhood with planet counts, etc. in the next 30-50 years. But GOING there??? Not bloody likely.

 

[vidar]

Thank’s for the tip.<br />But this half a century terminated project is not quite the same as an ACE.<br /><br />However, after browsing a while I came over the Project Longshot. It is a design from NASA in the early 1990 for an unmanned probe intended to fly to Alpha Centauri. It is powered by nuclear pulse propulsion, based on existing technology. Longshot massed 6.4 tonnes, which includes a 3.4 tonne energy storage system. It should be able to reach Alpha Centauri in 100 years (c/25).<br /><br />Now we are getting somewhere. Can this design be modified to reach c/10 or more?<br />

 

[vogon13]

40 years worth of materials science advancements, continuing nuclear weapons research and perhaps a 'staged' Orion concept might be able to add a few more percentage points to Orion velocity. Suspect not having to decel the entire pusher plate used for acceleration at destination would allow a big jump in speed. 8% C seems not unreasonable.<br /> <br />Also, keep in mind, Orion is not just sending a little Voyager probe, it is capable of sending vessels much larger than the aircraft carrier Nimitz. (IIRC, Nimitz masses 100,000 tons) <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[vidar]

Orrery21<br /><br />I am certain ideas like ACE have been proposed many times before. Until now the NASA Project Longshot seems to be the closest one. However, lots have been learned by the Titan and Mars initiatives. Some of these experiences should help making an ACE real.<br /><br />Photon and laser propulsion is a good and clean idea. But it’s hard to decelerate when the laser is out of reach or weak due to long distance. Some technologies are best for intra-solar system, like the solar sail, and others technologies for extra-solar voyages.<br /><br />Smaller is better, I think. Nano is terrific. However, I would like to see it work on Earth before relying on it at a remote and harsh place. The recent decade of miniaturization and quality improvements of transmitters, cameras and computers should benefit ACE a lot.<br />

 

[vidar]

8% c is very good. Still it will spend half a century on the journey.<br /><br />The past centuries idea of gigantic vessels should be reconsidered in this century.<br />I think it is necessary to rethink the whole idea with ‘smaller is better’ in mind.<br />Sending a scout to map new found territories is the main objective for ACE.<br /><br />Later, when the path is known and safe, its time to send larger vessels.<br />

 

[vidar]

It seems unlikely to get an ACE to the star system without the use of nuclear power. Then a major obstacle seems to be political due to the Partial Test Ban Treaty of 1963.<br /><br />In brief, the UN treaty is made ‘to prohibit, to prevent, and not to carry out any nuclear weapon test explosion, or any other nuclear explosion, at any place under its jurisdiction or control: in the atmosphere; beyond its limits, including outer space; or under water, including territorial waters or high seas; or ….’<br /><br />The project Orion was shut down in 1965. The Wikipedia says that: ‘Some authorities say that President Kennedy initiated the Apollo program to buy off the technical enthusiasts backing the Orion program. The recent book by George Dyson says that one design proposal presented to Kennedy was a space-going nuclear battleship, which so offended him that he decided to end the program.’<br /><br />I can very well understand that under Cuba crises, there was an overwhelming fear of launching a gigantic nuclear spaceship. Now 40 years later, the situation is very different. There are submarine ships, like nuclear fortresses, at the continental coasts. There are nuclear missiles enough to blast Earth several times. And nuclear plants are widely accepted as power source to the civilization. <br /><br />In short, a few minor reactors in outer space are no significant threat to civilisation anymore. And by the way, are all the space-actors bound to the treaty?<br /><br />The Test Ban Treaty should be changed in the UN to benefit true science.<br />

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>But I find it very unlikely to send manned missions to Venus or Mercury. These are no places for any human<p><hr /></p></p></blockquote><br />You arent thinking in three dimensions. Like i said, Venus is a paradise planet if you <i>dont go down to surface</i> but remain floating at the habitable height.<br />Simlilarly, Mercury ( or as a matter of fact, practically no celestial body ) is not a perfectly round sphere with equal surface conditions everywhere. Like said before, there are craters and who knows what under surface. There's ample living, exploration and industrialization room in solar system.<br />

 

[vidar]

Well yeah. <br /><br />Anyway, this topic is about Alpha Centauri Explorer.<br />No way Venus and Mercury will be discussed further here.

 

[vidar]

I do not know if the story is true. All I know is that anyone can read for themselves in the last paragraph under ‘The Orion project’ at http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion<br /><br />It must have been a hard political times in the 60’, where new, complex and dramatic decisions had to be made. Anyhow the decisions, someone had to be very upset, and not all the decisions were considered democratically ‘need-to-know’. But I think this topic should still be ACE today. Political disagreement about the past should be discussed elsewhere.<br /><br />The only reason to consider the political past is to revaluate it for the present and the future. I hope this thread can contribute to change the Test Ban Treaty to benefit true science.<br />

 

[john_316]

Okay I keep hearing about Project Orion over and over and heres my stuble questions?<br /><br />If Orion was built in space and then launched unmanned how soon can it travel to AC?<br /><br />How big and how often does Orion drop a nuke for propulsion?<br /><br />And how long will it take to reach even a 250,000 mph?<br /><br /><br />I was thinking perhaps for certain missions and project the odd thing might just work out better in the long run...<br /><br />

 

[vidar]

Reading about the Project Orion can be done at http://en.wikipedia.org/wiki/Project_Orion<br /><br />It was a theoretical project that was terminated. (And I do not think it could succeed.)<br />I think it was estimated to reach c/10. I think its destination would be Orion, not Alpha Centauri.<br />But please tell us when you have figured out the rest of the questions. <br /><br />The idea of the Orion Project is half a century old. <br />This topic is about the now and the future.<br />

 

[john_316]

44 years is a long time to goto Alpha Centauri...<br /><br />That would indeed have to be an Ark. Thus a crew would have to pro-create along the way and there is still no gaurantee that it would succeed if no habital planet is found there. <br /><br />Thus a probe mission would have to go first and then a human crew years later. It would kinda suck to get there and have to turn around and come back or worse get stuck there when the A bombs run out....<br /><br /><br />Now this all opens up a interesting subject.........<br /><br />Is the innerstellar medium the same as in the solar system medium?<br /><br />Thus is it possible when your so many AU out that the medium actually changes and thus makes innestellar travel faster and then the theories of Einstein no longer apply everywhere in the space medium? <br /><br />Because I beleive they have already done experiments of light in gases actually travelling faster than the speed of light in some tests.<br /><br />I am not going to say that instellar medium is different than in our solar system but perhaps the medium is completely subject to different laws.<br /><br />ok just a wild tangent...<br />