Infrastructure for a robotic mission to Alpha Centari

[willpittenger]

Suppose we were planning to send a robotic probe to the Centari system. I have listed below several challenges that would need to be overcome. What do you think about them?<ol type="1"><li>I assume the trip would require several centuries. Would anyone be listening to the probe when it arrived?<li>Once the probe arrives, you will need 4 years to send instructions to it and another 4 years to get a reply back. I assume having a probe that thinks for itself would help greatly. This might even have to include selecting its own targets once it arrives in-system.<li>I think that an incredible level of redundancy might be required for the probe to be working after several centuries.<li>If a sample return is desired, all time estimates double.</li></li></li></li></ol> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[3488]

I would have thought, that the best way for a FIRST mission is a using a<br />preprogrammed craft which would have a list of 'must dos'.<br /><br />IMO they would be,<br /><br />1). Get detailed SOHO like imagery of both Alpha Centuari A & B.<br /><br />2). Detremine current state of star spot & coronal activity of both.<br /><br />3). Carry out a distant survey of Proxima Centauri.<br /><br />4). Measure fields & particles.<br /><br />5). Look around for any planets.<br /><br />Whilst this craft is on route, build a second more capable craft, (many years later, <br />with vastly advanced technology)) to follow on,<br />that can communicate with both <br />Earth & the first craft, so it can 'learn' what the first<br />one has found out & be able <br />upon its arrival, carry out a far more sophisticated<br />mission.<br /><br />Perhaps making close encounters with any planets, their moons, asteroids, comets, as<br />well as far more detailed observations of the Alpha Centauri A & B pair.<br /><br />That's my opinion anyway.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[christine16]

Are you sure that Alpha Centauri has planets?

 

[baktothemoon]

Didn't we already debate this when we discovered Gliese 581c?

 

[willpittenger]

No, he wasn't. What he wrote: <font color="yellow">5). Look around for any planets. </font>/safety_wrapper> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

I wasn't aware of any such discussion. Besides, the Centari system will almost certainly get our first interplanetary probe.<br /><br />BTW: Are Jupiter or Saturn ever in position for a flyby that would send a probe to the Centari system? If not, we would probably have to provide all the acceleration with the probe's own engines (or a solar sail system). Such a flyby would be very helpful. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[Aetius]

I don't think a Jupiter flyby is gonna matter much delta-v wise, if your probe is going to Alpha Centauri. <img src="/images/icons/wink.gif" />

 

[alokmohan]

How much btime it may take to go there my our modern technology?

 

[solarspot]

IIRC, about 10 000 years Voyager-style. I would not want to launch a mission that would not reach it's destination for such a long time, as our civilization may or may not exist on Earth (hopefully off it tho).<br /><br /><br />

 

[scottb50]

From what I can find out the system doesn't seem like it would be worth going to anyway. Any planets would be subjected to rather violent gravity changes due to the proximity of the stars involved. We could probably learn more by investing in better sensing capabilities then sending probes. <div class="Discussion_UserSignature"> </div>

 

[willpittenger]

The biggest advantage to going there would be simply the timeframe. We can get there faster than any other option unless a flyby of one or more gas giants speeds things up. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[scottb50]

I would think we could develop more advanced sensing systems in less time then it would take to get to a system that offers little chance of finding anything of major importance.<br /><br />It still boils down to 10,000 years to get pictures we could get in four. Just look at the advances in the last 30-40 years in optics, Hubble was a huge leap but technology has brought ground based equipment to close to it's capability. It might take another 1,000 years but that's still a lot less then what it would take to send a probe. <div class="Discussion_UserSignature"> </div>

 

[qso1]

Christine16:<br />Are you sure that Alpha Centauri has planets?<br /><br />Me:<br />Excellent question and one not yet answered. There have been no reports as yet of planets confirmed orbiting this star system. This may be due in part to the system being a binary and probably not having a hot Jupiter. The vast majority of confirmed exoplanets are very near their host stars and tend to be several times Jupiter mass.<br /><br />The more complex orbital mechanics of the Alpha Centauri system may make seeking out more distant planets that much more difficult. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

alokmohan:<br />How much btime it may take to go there my our modern technology?<br /><br />Me:<br />current tech which has given us unmanned probes that have briefly reached 100,000 mph or more...lets assume a probe can sustain that velocity for the entire journey to AC. It will still take a quarter million years to reach Alpha Centauri. At Apollo escape velocity of 25,000 mph...sustained...the trip to AC would be a million years.<br /><br />Someone had mentioned 10,000 years but I did the arithmetic by dividing the 25 trillion miles to AC by 25,000 mph Apollo escape velocity and got 1 million years. But even 10,000 years would still be too long to me. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

willpittenger:<br />Suppose we were planning to send a robotic probe to the Centari system. I have listed below several challenges that would need to be overcome. What do you think about them?<br /><br />Me:<br />Great ideas and a few comments starting with item 1:<br />I hope we will have a major breakthrough in propulsion technology within the next century or so that will vastly reduce the transit time.<br /><br />Item 2:<br />Probe autonomy will be a requirement due to the signal transit times you mentioned.<br /><br />Item 3:<br />Redundancy would be beneficial even for a probe requiring a few years transit.<br /><br />Item 4:<br />Havent thought much on this one yet. You may recall I'm actually working on a graphic novel dealing with the first human mission to AC. A mission that early in the book references the pioneering work of unmanned craft that were sent to other star systems. For reasons I won't go into right now, the probes to AC were not sample return missions. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[mithridates]

Deep Impact's new mission has gotten me thinking about this subject. Since Deep Impact is going to be used to search for transiting planets in front of stars (I think), and since the more angles you have to look at a star the higher the chance is of finding a transiting planet, wouldn't it make sense to send out two probes both over and under the sun's orbital plane so that we could get a slightly different view of the system instead of the single head-on view we have now?<br /><br />I might be overestimating the possible value, but I wonder if it would be worth it to send a probe off on perhaps one or two flyby missions of asteroids way off the regular orbital plane and then off to function as a telescope able to see from a different point of view than the one we have on Earth. Something like MOST, perhaps, that is used sometimes to try to look for a transit when a new planet is discovered but not directly observed. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[holmec]

What about studying those stars with a SOHO type probe and maybe other sensors?<br /><br />You have 3 stars in the area (I guess that's a huge area). So you have the possibility of studying different stars up close. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[themanwithoutapast]

1. There is not much gained by sending a probe to Alpha Centauri to "monitor" things that we can also do with sophisticated space bound telescopes here. <br /><br />2. Any mission which has a mission duration longer than a couple of decades will not get funded within our lifetimes. Ergo, if you want an interstellar probe, it needs to go at speeds that are technically not feasible to reach today.<br /><br />3. The first interstellar probe will very likely not slow down at its destination, because this would make matters a lot more complex and the spacecraft by magnitudes heavier than an interstellar probe that does a flyby.<br /><br />4. If humans ever send something to another star system which actually still functions when it reaches such star system, that "something" will very likely have a goal other than sending back information - that is some sort of space colonization (less likely colonization with humans living during the time of travel) is more likely to be among the first interstellar missions (if there will be any) than simple interstellar probes that are incapable of providing much more information than what we can get from right here by spectroanalysis etc.<br /><br />5. My ultimate prediction: A clear picture of an Earth-like planet with an atmosphere and water will be available long before the construction on any interstellar spacecraft will begin.

 

[MeteorWayne]

5.) That's likely the only thing that would inspire such a mission <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[holmec]

<blockquote><font class="small">In reply to:</font><hr /><p>I assume the trip would require several centuries. Would anyone be listening to the probe when it arrived?<p><hr /></p></p></blockquote><br /><br />[edited]<br />I did some rough calcs using ion drive to Alpha. Running constantly the trip could take 26.83 years. This is if you could make a ion thruster to run that long. I used the optimistic (0.0098 m/s²) performance for the ion thruster and it came out to be 26.83 years (rounded off, of course). Max velocity of 9.96E+08 km/hr. <br /><br />I also used the pessimistic (0.000098 m/s²) performance. It came out to be 268.17 years thruster time and a total travel time of 268.41. Max velocity of 9.95E+09 km/hr.<br /><br /><br />I didn't take into account the relativity factor.<br /><br />Well our current tech has a lot of work to do to meet the challenge.<br /> <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[themanwithoutapast]

<blockquote><font class="small">In reply to:</font><hr /><p>I did some rough calcs using ion drive to Alpha. Running constantly the trip could take 26.83 years. <p><hr /></p></p></blockquote><br /><br />Not possible. Current ion drives have isps of 2000-3000 sec and rather low thrust. It is not even theoretically possible to create a spaceships with that many ion driven engines in parallel and the amount of fuel to propel the spaceship for 26 years, not even mentioning that it would not reach the velocity you suggest.

 

[holmec]

These are real numbers I used. Do the calcs yourself.<br />wiki numbers <br /><br />Deep Space 1 had a performance of 0.0043<br />meter per second^2 or 9600 miles/hour^2.<br /><br />Deep Space 1 link<br /><br /><br />But your right creating an ion thruster to run so long is seriously dubious. And if you did what kind of performance could you get? Probably much lower than stated here. The sheer mass of the Xenon gas would be huge.<br /><br />if you don't use a thruster at Alpha, your just doing a flyby. I would think you would want a probe in orbit there.<br /><br />Well this begs the question then, how much max thruster time is reasonable for an ion thruster? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[themanwithoutapast]

These are real numbers I used. Do the calcs yourself. <br />wiki numbers <br /><br />Deep Space 1 had a performance of 0.0043 <br />meter per second^2 or 9600 miles/hour^2. <br />----------------<br /><br />Sorry, but a spacecraft is not scaleable as your calcs suggest. It is not a question of an ion thruster running 20 years, it is a question of building one (or clusterin more) that large that it can propel your spacecraft with the required propellant for such a long time. Technically spaceprobes with current ion-drive technology can not go much faster than for instance the Voyager probes (that ultimately gained a lot of speed by gravity assists)

 

[willpittenger]

At least until we send that probe. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

Any idea how long a solar sail might need to get there? Previously in another thread, I suggested a sail that was several miles across serving as a launch platform for a second sail that was at least 10 times larger. The first sail would deorbit and move radially through the solar system. Somewhere at a distance comparable to Pluto's orbit, it would release the second sail. That sail would probably have to maneuver to avoid KBOs and Oort cloud objects. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>