can we use a comet to propel a space probe

[R1]

Is there any way a probe could be built that can use a comet to speed it up?<br /><br />an incoming comet can be as fast as 1,600,000 mph, about 42 times<br />faster than the speed of a Voyager probe.<br /> <br />If we could somehow land a probe on a comet, and wait for the right speed, and then<br />separate them, we could have the probe travel the entire distance that a Voyager probe has traveled<br />over the past 30 years in about 8 or 9 months.<br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[origin]

If we could land on a comet going 1,000,000 mph then we could have the space craft traveling at 1,000,000 mph so why land?<br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[billslugg]

What you have got to do is to fly a trajectory that would have the comet pass by a few miles in front of you. Awaiting the comet would be a penetrator connected to you by several miles of 100 pound fishing line. You would do a slingshot/trebuchet maneuver cutting the line at just the right moment. <br /><br />Bill Slugg <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[Mee_n_Mac]

I'm not sure about that penetrator. The comet might not have enough cohesiveness to allow it to "stick". How about a net made of some bungee cords ?<br /><br /><br />... strips of duct tape ??<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

 

[billslugg]

Haw about we have TWO probes hanging out in space with ten miles of line between them, and the comet runs into the center of the line. The probes will wrap around and, providing they don't slam into each other, can each be put into high speed trajectories. No anchors or net needed. <br /><br />Bill Slugg <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[qso1]

The problem is orbital mechanics. Lets say Voyager was built to utilize the comet as propulsion. It would most likely have had to wait for a comet to approach earth at the right time, then follow the path Voyager II followed meaning Jupiter, Saturn, Uranus and Neptune would have to be in exactly the right positions (Plus or minus a few hundred miles) for this to work as the comet would basically have to follow the gravity assist trajectory Voyager II did.<br /><br />If one happens to observe a comet headed this way and calculates that it would pass a good target such as Jupiter then this would work out well but unfortunately, this kind of situation arising is normally extremely rare.<br /><br />Comet Enke comes to mind but when its out by Jupiter, is it always passing close enough to provide a platform for a useful mission? I can check this in "Starry Night" I guess. <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>

 

[wick07]

It might be useful if you were making a probe specifically to explore the outer reaches of the solar system, then you wouldn't have to worry about hitting a specific target (aka Planet), but could just toss your probe out into space. <div class="Discussion_UserSignature"> <p><font color="#3366ff"><strong>_______________________________<em> </em></strong></font></p><p><font color="#0000ff"><em>"</em>If you are surrounded by those who constatly agree with you, then you're in an intellectual vacuum.  If you feel like trying to make a difference, you have to BE different.  How can you do that without interacting with those who are different from yourself?"</font></p><p><font color="#0000ff">-  a_lost_packet_</font></p> </div>

 

[vogon13]

If you match orbit with a comet, and the comet 'magically' disappears, you are still on the same trajectory as the comet and will still hit the same speed when you are at closest approach to sun.<br /><br />So what do you need with the comet ??<br /><br /><br /> <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>

 

[qso1]

Wick07:<br />t might be useful if you were making a probe specifically to explore the outer reaches of the solar system,<br /><br />Me:<br />That it would and one day it might actually happen, nano probes could ride comets and observe deep space. <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>

 

[vandivx]

didn't Japanese probe crash land on a comet not long ago (I think it was just bombarding projectile they used to hit the comet) and there was crash landing on that potato object http://near.jhuapl.edu/ which was asteroid though<br /><br />the idea is certainly interesting and I don't think one would care about exploring planets faster way that way but rather getting fast ride out of solar system and learn something about comets and where they go etc.<br /><br />however I don't think it possible to hitch a ride on or with comet like it might be with asteroid which are slower and bigger, at least that's my uneducated impression, I know the NEAR probe was able to get into close gravitationally bound orbit and if it had some inflatable bags it might even have worked after crash landing on it... any idea where that asteroid (Eros) is located these days? and do asteroids have 'interesting' paths<br /><br />/edit http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=433;orb=1<br />it looks like this asteroid moves within inner solar system orbit only<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

That was the US Deep Impact probe in July 2005.<br />It impacted comet 9P/Tempel. <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>

 

[vandivx]

thx, you can tell I only have very poor memories of these things as I don't need such knowledge, like Sherlock Holmes told Watson that he doesn't know or care about Moon orbit or what he was asked about, he didn't need such knowledge for his career and its the same with me<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

You can read this thread for a memory refresher. <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>

 

[Mee_n_Mac]

You asked "can we use a comet to propel a space probe" in the title of this thread and then proposed hitchhiking on one to gain it's velocity. As origin (and others) pointed out, this is impractical. But perhaps a different answer to the question might be the ticket ....<br /><br />Let me propose another "solution" (that's probably as impractical as yours but what the hey) that hopefully will amuse the audience and perhaps provoke some thought. Comets emit a lot of "stuff" as they approach the Sun and some of this stuff might make a good fuel. Hydrogen and hydrocarbons make up a (small) portion of the coma. Could a spacecraft make use of this fuel as it travels and thereby lessen the mass it must carry. Less mass will enable higher velocities which was the desired outcome. Is there someway to collect the debris trail, sort out the fuel portion and use it ? <br /><br /><br />Sure there are problems but could it be made to work with today's, or next decade's, technology ? Might we use a comet to propel a space probe ?<br /><br /><br /><br /><br /> If this sounds like a intraplanetary version of a bussard ram scoop, it should as I'm shamelessly copying the concept. <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

 

[MeteorWayne]

That's an interesting question.<br /><br />My first reaction is no, because the cost of gathering the "fuel" might not be worth the risk of impact, and the fuel might not be worth much.<br /><br />However, it's a good thought, and I'll check into the propulsive value of the gas surrounding comets. <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>

 

[Mee_n_Mac]

<font color="yellow">That's an interesting question.</font><br /><br />Cool ! That's all I was hoping for.<br /><br />Sometimes it's fun to explore a crazy idea. Besides just as the OP inspired me, perhaps my question will inspire yet a better idea ... or at least one as amusing. <img src="/images/icons/smile.gif" /><br /><br /><br />{And on that note, I await Bill Slugg's input ... <img src="/images/icons/wink.gif" /> } <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

 

[MeteorWayne]

Ohhhh Noooooooo.<br /><br />Mr Billlllllll!!!!!!!!! <img src="/images/icons/laugh.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>

 

[vandivx]

http://www.nasa.gov/mission_pages/deepimpact/main/index.html<br /><br />how about if instead of dummy projectile we shot at it at slower landing speed some kind of probe that would land on the comet's surface and stay there and gather data and broadcast them back here as it flew out of the solar system<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[R1]

Isn't vogon right? the probe in the same path as the comet's orbit should cause<br />it to fall towards the sun at the same speed, in this situation we just need the probe to be able to approach the<br />sun, but capable of deep space. <br /><br /> It need not get too close to the sun either, or else could we somehow use a comet to eclipse the sun and use it<br />as a shield during it's solar proximity? The probe could have a conical shield, or it could be a large collector dish,<br />or a variable umbrella type, modulating its shape depending of what effect is needed. <br /><br /> In other words could the tail particles (and force) be used in any meaningful way?<br />As the comet-and-probe pair approach the sun to dangerous proximity, the umbrella would open and use the comet tail<br />to increase the probe-to-sun distance, all while the comet still shields the probe.<br /><br />Mee_n_Mac also has a good idea, if we could somehow use comet gases for fuel.<br /><br /> If the speed of a comet is too high to work with it initially, we simply have to go further out, when the comets turn<br />around, some are thought to slow down to as little as 250 mph.<br /><br />But anyway, I don't necessarily mean we have to land on a comet that is going at top speed at the time, but rather<br />devising any conceivable way of using a comet. Its orbit, its shade, speed or lack of it, its tail, gases, dust, or<br />their force, anything, you name it.<br /><br />vanDivx, that's a good idea too, but the miniature probe like that probably would get lost on its following approach to<br />the sun, but that's a good idea too, those could be small-scale probes, and many could be planted on asteroids and comets,<br />to give us better, more accurate information, some could even double their purpose as communication relay stations,<br /> for all existing and future probes.<br /><br /> <br />edit: qso1, I think I remember Enke vanished, didn't it?<br /> <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

No Encke is still around <img src="/images/icons/smile.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>

 

[gammarayburst]

Just make a big solar sail and hitch a ride on the solar wind which was clocked at over 1 million mph. No need to hitch a ride on a comet.

 

[kmarinas86]

Gravity of a comet is too weak for this to be practical.

 

[robnissen]

<font color="yellow">There is no such thing as a free lunch.... or a free ride on a comet. Inorder to land on the comet you must match the comet's speed. Thus you match the comets orbit. If the comet was not there your spacecraft would be in the same otbit as the comet....you do not get a free ride. </font><br /><br /><br />While that statement is true, it misses the point. Comets do not orbit at constant speeds because their orbits are typically highly elliptical. Comets when they are closest to the sun, reach very high speeds, far away from the sun they just putt along, I believe halley's comet slows into the tens of miles/hour range (IIRC). Now, I don't know if this could be usefully used, because if you send a probe out to land on Halley at the furthest point of its orbit, you would wait 38 years for it to reach its max speed, and you would be very close to the sun, but it you then lifted off the comet in the direction of travel, your probe would have a very high speed relative to the sun. But between taking many years to reach Halley's, then 38 years to accelerate AND returning to the inner solar system, you would probably have been better off to skip the comet in the first place. But that is not to say that there aren't other shorter period comets that would not give a boost that perhaps would be worthwhile.

 

[billslugg]

Rob<br />If you go way out in the solar system and match Halley's crawl, you have invested little energy in velocity but a lot of energy in getting way out there. Nothing gained. The point is that if you use energy to match the speed of the comet, anywhere along its orbit, then there is no energy to be gained from the comet. The only way you can get energy from a comet is to be sitting there when it goes by and latch onto it somehow, either gravitationally or with a rope. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[robnissen]

<font color="yellow">The comet will NOT provide any extra velocity to the spacecraft that lands on it no matter where it lands on the comet and where it leaves the comet.</font><br /><br />I don't agree. Halley's comet slowest speed is about 700 mph, and its highest speed is about 125,000 mph (both relative to the sun). If you land when it is 700 and take off when its 125,000 you have gained over 124,000 mph of velocity. I get that if you take off in the same direction as the comet, that you will end up in the same orbit and eventually slow back down to 700 mph and be in the same orbit as Halley, but that is assuming that you don't provide any additional thrust when you take off and that is also assuming that you go in the exact same direction as Halley. If you provide more thrust and a different orbit, perhaps to get a gravity assist from the inner planets, you could maintain some of that additional velocity.