Interstellar Probes - Current Capabilities

[nrrusher]

<br />Does anyone know or have seen, what the current capacity is for an interstellar probe? As far as speed, transmission, duration, etc.?<br /><br />If we were to use our the best tech we have right now, what is the soonest arrival we could have at our nearest stellar neighbor (Alph Centauri I believe) assuming we launched it within a couple years and sent it on its way.<br /><br />NR

 

[MeteorWayne]

Well, just to give you some ballpark numbers...<br /><br />Alpha Centauri is about 4.3 light years away; that's about 274,900 AU.<br />The fastest spacecraft we've launched heading out of the solar system in New Horizons, on it's way to Pluto, it is currently doing a bit over 4.3 AU per year. That's an example of currently tested and functional technology.<br /><br />Plug those numbers in and you cruise into the Centauri system in 63,200 years. These are just back of the envelope (literally) calculations.<br />Of course NH will be travelling quite a bit slower by the time it gets to Pluto and leaves the "planetary" part of the solar system, but this gives you a feel for the current reality.<br /><br />Now when we have ion engines that we can ensure they will run for a hundred years, we can probably pick up the speed a bit...if you can launch enough mass (or collect enough) to use as propellant. However, you asked what we can launch within a couple of years, so probably have to stick with good ol' rockets.<br /><br />Wayne <br /><br />Edited to correct NH speed in AU/Yr <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>

 

[MeteorWayne]

Your post inspired me to check.<br />NH launch weight 478 kg (1054 lbs)<br />Includes 77 kg (170lbs) hydrazine propellant for maneuvering<br />and a 30kg (66 lb) science package.<br /><br />The antenna is a 2.1 meter (83 inch) dish. <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>

 

[nrrusher]

<br />I was thinking along the lines of the solar sail as well. I have heard estimates that with a good launch trajectory and sail deployment after a good boost with the best rockets, an average velocity of almost 1/10 ce could be attained, which would put us there in under 50 years.<br /><br />That seemed a little out there, but I wanted to hear what others thought. Gee whiz, if we could be there in 50-60 years, why the heck aren't we on the ball with this one? <br /><br />If I am 80 some years old, and we are receiving signals from another star system, our own signals, I would just have to say, OK, I have now lived to see the coolest thing ever...I am ready to die now...<br /><br />NR

 

[MeteorWayne]

Well there's only really been one solar sail test, and the rocket part failed <img src="/images/icons/frown.gif" /> so it returned no useful data as far as the sail is concerned.<br /><br />Sure, if you can get to 0.1 C, then Alpha Centauri is only 43 years away.<br />But that's 15,000 times faster than NH.<br />And while a solar sail works close to the sun, by the time you get to pluto, the sun isn't accelerating you much at all. So you need to get to 0.1 C pretty much before you get to Saturn. 0 to 300,000 km/sec in a few months. I'm skeptical that can be done anytime soon.<br /><br />After all, you did specify "within the next couple years" <img src="/images/icons/smile.gif" /><br /><br />Wayne <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>

 

[nrrusher]

<br />Accelerating from 0 to 300,000,000 meters per second in 3 months time (84 days) would give an average acceleration of 4.217 g's, or 41.34 m/s squared.....<br /><br />Now, we just need to figure the mass of the probe and the solar sail, the initial speed before sail deployment, deployment location (i.e. Mercury/solar orbit or earth orbit, etc.) and the thrust provided by a solar sail per surface area to get the thrust needed......this oughta be fun........<br /><br />NR

 

[nrrusher]

<br />ALSO, the thrust provided relative to the decreasing distance from the sun...........

 

[nrrusher]

<br />To make things a little simpler, lets assume....<br /><br />All on board fuel will be utilized to decelerate and additional maneuvering at target location. It would be nice to give it a couple booster rockets like the shuttle, but we can figure that in afterward. Plus, due to relativity, the faster you are going, the less help rockets will be......<br /><br />More coming.......<br /><br />The Solar Sail will be the primary means of propulsion right from the start, minus the obvious orbital speed at Mecury orbit.<br /><br />We will us

 

[nrrusher]

<br />I was assuming that the sail/probe setup would be flipped around upon nearing the the new system in order to provide deceleration. Depending on the output of the star, it might take more/less time, but if we can use it to speed up, using it to slow down is the same.<br /><br />Having gone that far, I would intend to stay a while. I would suggest putting it in a stellar orbit and use its instruments to analyze the planets and such...perhaps trying to find an interesting one for further study.<br /><br />NR

 

[MeteorWayne]

Well, then you are at least doubling the travel time, so now it's 86 years. <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>

 

[nrrusher]

<br />I guess we will need to reach 20% ce then.... <img src="/images/icons/smile.gif" /> Initially I had meant and figured on a 10% of ce AVERAGE velocity, which would then entail a 20% max velocity, obviously....so the acceleration numbers I stated are still good for a stopover mission.....<br /><br />If the SIM Planetquest Mission could get out of budgetary hell, we might actually know within my lifetime if there is anything at the Centauri's worth seeing/probing. <br /><br />This puts me on a small philosphical note/rant.<br /><br />There are two ways to run a race. One, try to run faster/better/farther. Two, try to make sure everyone else runs slower/trips/doesn't run faster than you.....<br /><br />I feel like America, and not just our country, but our culture in general, has the sickness of trying to outdo one another, not by running faster (which is healthy) but by cheating and/or causing others to trip up.<br /><br />Case in point - instead of making our country stronger, so strong that no piddly little terrorist group can really pose a serious threat, we try to cut their legs out from under them. And since they just keep getting back up, we have to do it over and over again......<br /><br />How about we just put on better athletic shoes and run to fast for them to catch????<br /><br />Anyway, I criminaly digressed off topic there....<br /><br />SIM Planet Quest.....at least the Centauri's are prime targets if and when it ever gets off the ground.<br /><br />NR<br /><br />

 

[thalion]

If we're talking about technology and monies we have in hand *right now*, this comes closest to viability:<br /><br />JPL Interstellar Probe Overview (proposal only, and an old one at that):<br />http://www.lmsal.com/sec/Roadmap/AppendixA/isp.html<br /><br />Even if we double or triple the speed of this mission, we're talking a trip time of thousands of years. Don't know if ion drives would be an improvement, but doubt it--this is pretty much what we have to realistically work with in 2007.<br /><br />

 

[nrrusher]

<br />Boy, talk about this idea being sandbagged. The solar sail testing keeps getting the legs knocked out from under it, and the Planet Quest mission keeps losing funding. <br /><br />Thanks for the converse though. <br /><br />Just for fun I am going to build a spreadsheet that I can simply plug in/ad hoc the best numbers currently available for solar sail propulsion capabilities. As they improve just popping in new numbers will give us the current best time to target. I will post it for second opinions when done....<br /><br />NR

 

[MeteorWayne]

Sounds like a great idea! <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>

 

[3488]

Ion drives so far have been pretty crap.<br /><br />It took Smart 1 the best part of a year to reach the MOON, & the one onboard DAWN<br />is pretty crap too, taking 4 years & 2 months to reach nearby 4 Vesta, which really could be<br />reached far sooner with proper propulsion & effective retro rockets (mind you<br />this does not detract from the fact that DAWN is a superb, capable spacecraft).<br /><br />The solar sail needs to be proven first, but unfortunately was lost.<br /><br />That could well have huge promise, but really needs to start from a point very close<br />to the Sun, perhaps the perihelion distance af asteroid 3200 Phaethon, where<br />the solar wind will be very strong. Then the solar sail, once getting up speed, will<br />be a very effective method of leaving the solar system. Of course, it wll generate <br />no thrust in intersteller space, but will be moving very fast. Then the<br />'solar wind' of the destination star could be used as a brake!!!!!<br /><br />So really despite the hype about it, it is useless as a primary form of propulsion <br />@ the current time. Maybe when or if Ion propulsion has the same performance as normal<br />chemical rockets, it is really best used for pointing, stabilisation, not really for<br />propulsion.<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>

 

[nrrusher]

AB, I assume you are referring to Ion drives in your last paragraph....... I'm not much into those at the moment either.<br /><br />I was considering a combination of Solar Sail/Mag Sail. Both have their advantages, and if you have the Solar Sail structure up anyway, why not energize the structure and take the additional advantage of the solar wind particles as well as the photons....<br /><br />NR

 

[h2ouniverse]

in your calculation of equiv acceleration, you have to take into account relativistic effects to approach c.<br />Unfortunately the quantity of energy needed to accelerate close to c increases dramatically. <br /><br />Regards.

 

[MeteorWayne]

At 0.1 c the relativistic effects don't make much difference. And no one has suggested a realistic method to obtain higher speeds where it would be needed in the calculations. <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>

 

[robnissen]

First, the good news: It may be possible to continue to accelerate a solar sail after Saturn by using lasers, such that you would not need to reach .1c by Saturn.<br /><br />Now the bad news: interstellar dust particles hitting a solar sail at .1c would quickly put it out of commission. We must create some sort of deflector screen in front of the ship. One possibility is an ice wall, that would be replinished as needed. Of course that would mean storing water on the solar sail, which would add mass, which would slow it down, etc. We have a LONG way to go before we will get anywhere close to .1c.

 

[MeteorWayne]

And where are the lasers, and how are you going to provide the gobs of power required?<br /><br />Sheesh, sometimes even though dreams are great, a reality check is needed! <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>

 

[nrrusher]

<br />Laser research is pretty hot and heavy right now. Due to the military nature of a lot of it though, I am sure they are a lot farther along than what we would know.<br /><br />The tough part would be getting it space based, regardless of whether we use laser, solar concentrators/focusers/mirrors, whatever. Which just brings us back to launch capacity/cost....the ol' albatross that seems to insist on being a hurdle no matter what we want to do. It seems there is almost always a way to do something, ifwe could just get past that. My problem solving technique is bottleneck removal, and launch capacity is by far the biggest bottleneck we have right now, now matter what it is we are trying to do.......<br /><br />As far as space debris entirely destroying a solar sail. I know that is a concern with anything we do in space. Consider the Voyagers though. Even though they are not at .1ce, they are still moving pretty darn fast and have managed to survive this long without a pebble wiping them out. Space Dust collisions are a secondary issue in my mind, and compared to just getting the thing moving that fast, that is a minor hurdle I would think. <br /><br />I would be interested to see how a radar/collision avoidance or particle elimination system would work on a probe though. How would moving that fast affect a tracking system that has the responsibility of scanning for debris in the path of the probe?<br /><br />

 

[robnissen]

<font color="yellow">As far as space debris entirely destroying a solar sail. I know that is a concern with anything we do in space. Consider the Voyagers though. Even though they are not at .1ce, they are still moving pretty darn fast and have managed to survive this long without a pebble wiping them out. Space Dust collisions are a secondary issue in my mind, and compared to just getting the thing moving that fast, that is a minor hurdle I would think. </font><br /><br />Yes, but. So far Voyager 1 has traveled slightly over 100 AU, less than .04% of the way to AC. More importantly, Voyager 1 is traveling at .000057c. The difference between being hit by a dust particle going .000057c and going .1c is MUCH greater than the difference being hit by a dropped bullet and a rifle bullet. Interstellar dust will be a HUGE issue to overcome at .1c.<br />

 

[dragon04]

I'll beat a (well almost) dead horse here.<br /><br />A mission that used a nuclear pulse propulsion system a la the original Orion concept could approach .1<i>c</i> velocities.<br /><br />Even .05c would get a probe to the Centauri system in under a century.<br /><br />That's really not a comforting notion though. How would we transmit any data back to Earth?<br /><br />The mission profile would almost have to be (with current technology) to spend 80 years getting there, a couple years gathering data, and then another 80 years coming back.<br /><br />Not impossible, but not very practical in terms of cost-effectiveness versus potential return for data gathered.<br /><br />Obviously, I'm also disregarding that UN Treaty that prohibits nuclear weapons in space as well. I think that if such a mission were multinational in nature and with all nuclear powers invested in it, the treaty issue could be circumvented though.<br /><br />Then there's the issue of getting all those bombs into space and building such a probe in LEO. More than just hard core environmentalists would blow a gasket if an Orion type mission was based on a ground launch if nuclear detonations were required to get the ship into space.<br /><br />But the operative point is that it's within our capabilities to do right now. <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[vogon13]

A weapon is a weapon.<br /><br />A propulsion module is a propulsion module.<br /><br /><img src="/images/icons/wink.gif" /><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]

Without doing the math etc. I'm just going to say that the velocity would be well below half a million miles per hour. But even half a million miles per hour is still well under .1 percent SOL or well over 4,000 years to get to Alpha Centauri. The idea of sending a Saturn-V or Saturn class NERVA upper stage is probably possible within a decade, no more than two decades (Allow for NERVA development) but as an interstellar mission craft...highly impractical IMO. <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>