Status of spacecraft after their missions ended

[brellis]

A lingering question in my mind: there are many "past" interplanetary missions where the crafts themselves are in various states of suspended animation?<br /><br />NASA made headlines when it contacted Pioneer 6 on the 35th Anniversary of its launch in 2000. Theoretically, P6 is still alive and well today.<br /><br />Are other spacecraft from past missions still functioning?<br /><br />Is it possible that the MER missions will be terminated before the rovers actually expire?<br /><br />How much energy is expended by the Voyagers now? Will their Interstellar missions end with life left in their RTG's? <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[qso1]

Just off the top of my head, the Voyagers are still sending back data and IIRC, they are to remain funded through the year 2020 which is when scientists theorize they will go through the heliopause. This assuming they do not break down on their own.<br /><br />I'd have to look through the data to see what craft are still functioning. Most of the ones, or probably all the ones launched prior to the mid 1990s, except the Voyagers are all no longer funtioning.<br /><br />The Viking 1 lander for example, was still functioning into 1982 and then had to be shut down due to errors in routine software uplinking.<br /><br />I suspect due to the unbelievable success of the MERs, they will be funded till they expire. Only the most idiotic spaceflight critic would cut funding of these robots prematurely.<br /><br />I don't know the exact answer about the Voyagers energy, but I would say that the RTGs will probably still have energy available after the Voyagers are shut down.<br /><br />Below is a link that may go a long way towards answering your questions.<br /><br />http://en.wikipedia.org/wiki/List_of_planetary_probes<br /><br />I usually check more than one link if the question is important enough. <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>

 

[adrenalynn]

IIRC, Voyager 2 will go to power sharing in 2015ish. Sometime after 2020, it won't be able to power any single instrument anymore.<br /><br />What you see is that after they shut down the power, the batteries can build some residual charge. That's why they were able to contact Pioneer 6 for a short time after they had shut it down. <div class="Discussion_UserSignature"> <p>.</p><p><font size="3">bipartisan</font>  (<span style="color:blue" class="pointer"><span class="pron"><font face="Lucida Sans Unicode" size="2">bī-pär'tĭ-zən, -sən</font></span></span>) [Adj.]  Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.</p><p><strong><font color="#ff0000"><font color="#ff0000">IMPE</font><font color="#c0c0c0">ACH</font> <font color="#0000ff"><font color="#c0c0c0">O</font>BAMA</font>!</font></strong></p> </div>

 

[qso1]

Sounds pretty close to something I saw not too long ago but could'nt recall the specifics, thanks. On the battery thing, engineers never really know how long their probes will last so they tend to assign a value based on previous experience. I doubt anyone involved with the Pioneer 6 probe would have imagined the batteries still having enough residual charge to make it possible to contact the probe decades after it was to have exceeded its life span.<br /><br />Who knows how long the RTGs will have residual power. <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>

 

[brellis]

<font color="yellow">What you see is that after they shut down the power, the batteries can build some residual charge. That's why they were able to contact Pioneer 6 for a short time after they had shut it down.</font><br /><br />ahh, so they can put the craft into a safe mode, and call it back later if possible, cool <img src="/images/icons/cool.gif" /> <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[vogon13]

The plutonium in the Voyage RTGs will remain potent for centuries. The electrical power output decreases over time due to radiation damage of the thermocouple junction material.<br /><br />The damage is cumulative and irreversible.<br /><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>

 

[ashish27]

but even if all systems shut down won't the spacecraft continue to move due to inertia? is there anything that can offer resistance?

 

[adrenalynn]

It will <b>tend to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force</b><br /><br />Thank you, Sir Newton (not to be confused with the ground up and breaded fig cookie...) <div class="Discussion_UserSignature"> <p>.</p><p><font size="3">bipartisan</font>  (<span style="color:blue" class="pointer"><span class="pron"><font face="Lucida Sans Unicode" size="2">bī-pär'tĭ-zən, -sən</font></span></span>) [Adj.]  Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.</p><p><strong><font color="#ff0000"><font color="#ff0000">IMPE</font><font color="#c0c0c0">ACH</font> <font color="#0000ff"><font color="#c0c0c0">O</font>BAMA</font>!</font></strong></p> </div>

 

[willpittenger]

I think the question had to do with what "unbalanced forces" could act on it. There are two main possibilities.<li>Gravity -- Until it is deeper in the gravity well of some object (like another star) other than the Sun that it is in the Sun's gravity well, gravity will slow the probe down. In the process, the probe will also curve slightly back towards the Sun.<li>Drag -- The material the Voyagers are going through adds a slight amount of drag. Again, the probe would slowly slow down and turn back slightly towards the Sun.<br /><br />Having said that, I doubt either force will affect either probe much. We would need some pretty extensive calculations to detect the changes.</li></li> <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>

 

[adrenalynn]

I'd imagine the friction (or "drag" if you prefer) would have too be pretty darned small out in the far reaches. Do you really think there'd be any kind of measurable/calcuable possible friction?<br /><br />Gravity will certainly act upon it, but out past the edge of the solar system, I agree with you that it's going to be pretty unmeasurable for quite some time. Long way to the nearest neighbor's house. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p>.</p><p><font size="3">bipartisan</font>  (<span style="color:blue" class="pointer"><span class="pron"><font face="Lucida Sans Unicode" size="2">bī-pär'tĭ-zən, -sən</font></span></span>) [Adj.]  Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.</p><p><strong><font color="#ff0000"><font color="#ff0000">IMPE</font><font color="#c0c0c0">ACH</font> <font color="#0000ff"><font color="#c0c0c0">O</font>BAMA</font>!</font></strong></p> </div>

 

[willpittenger]

Just don't expect the probe to do much besides say "Hello." When they were trying to get pictures of Shoemaker-Levy 9's impact, the Voyagers were of no help. When they turned the cameras off, they did so permanently. They might do the same with the other instruments after passing heliopause. <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]

<blockquote><font class="small">In reply to:</font><hr /><p>Do you really think there'd be any kind of measurable/calcuable possible friction?<p><hr /></p></p></blockquote><br />Well, the sensors are picking up some turbulence. So there is something there that the Voyagers are going through. Just not enough for either probe to end up off course. <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>

 

[brellis]

I wondered about the fate of Mars Global Surveyor, which went out of communication late last year. It likely expired within a relatively short period of time because of disorientation - solar panels not pointed at the sun. It is likely in the same orbit as when contact dropped.<br /><br />There's something very romantic about these intrepid spacecraft existing intact in (and out!) of our solar system. I think about the Huygens probe that landed on Titan. It was still transmitting when Cassini passed out of range. What did Huygens discover after that point, while it was still functioning? Maybe it started raining methane. It likely will rain at some point - the Titan monsoon season is coming.<br /><br />How 'bout the rover driven by the Apollo astronauts? It prolly had some gas in the tank when they left <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[qso1]

The rovers probably would have gas in their tanks had they been gas powered. But instead, they were electric motor powered. Still, they have been on the moon nearly as long as I've been alive. <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>

 

[brellis]

<font color="yellow"><br />The rovers probably would have gas in their tanks had they been gas powered. But instead, they were electric motor powered.</font>- yah, that was a bit of figurative fuel license on my part <img src="/images/icons/wink.gif" /><br /><br />Considering how long ago that was, ain't it curious that we haven't made more headway in fuel economy on earth? <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[qso1]

I kind of thought the fuel license was invoked and yeh, considering what the future was supposed to look like. In 1971, we were to have SSTs going into service in 1976 but our SST was axed in 71. A proposed 1981-82 manned Mars mission was already axed by then. As for cars, rotary engine was the wave of the future circa 71. <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>

 

[brellis]

The Galileo mission was exceptional in that the end of its mission was dramatic and purposeful, albeit not quite the ideal outcome -- IIRC it fell through Jupiter's atmosphere at an unusual time/location compared to what we've known about it.<br /><br />Here's another great exception:<br /><br /><font color="orange">Magellan Significant Events for Week Ending 10/14/94<br /><br />1. Communication with the Magellan spacecraft was lost early Wednesday morning, following an aggressive series of five Orbit Trim Maneuvers (OTMs) on Tuesday, October 11, which took the orbit down into the upper atmosphere of Venus. The Termination experiment (extension of September "Windmill" experiment) design was expected to result in final loss of the spacecraft due to a negative power margin. This was not a problem since spacecraft power would have been too low to sustain operations in the next few weeks due to continuing solar cell loss.<br /><br />Thus, a final controlled experiment was designed to maximize mission return. This final, low altitude was necessary to study the effects of a carbon dioxide atmosphere.<br /><br />2. The final OTM took the periapsis to 139.7 km (86.6 miles) where the sensible drag on the spacecraft was very evident. The solar panel temperatures rose to 126 deg. C. and the attitude control system fired all available Y-axis thrusters to counteract the torques. However, attitude control was maintained to the end.<br /><br />3. The main bus voltage dropped to 24.7 volts after five orbits, and it was predicted that attitude control would be lost if the power dropped below 24 volts. It was decided to enhance the windmill experiment by changing the panel angles for the remaining orbits. This was also a preplanned experiment option.<br /><br />At this point, the spacecraft was expected to survive only two orbits.<br /><br />4. Magellan continued to maintain communication for three more orbits, even though the power continued to drop below 23 volts and eventually reached 20.4 volts. A</font> <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[qso1]

I tend to think the MERs will eventually shut down rather than be shut off unless someone in the MCC sends up the wrong S/W.<br /><br />As for Beagle, I guess your question depends on how the ESA runs their programs. Would they withold an important discovery? At this point, I guess only they know. <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>

 

[brellis]

<font color="yellow"><br />As for Beagle, I guess your question depends on how the ESA runs their programs. Would they withold an important discovery? At this point, I guess only they know.</font><br /><br /><img src="/images/icons/laugh.gif" /> - good one <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[willpittenger]

<blockquote><font class="small">In reply to:</font><hr /><p>unless someone in the MCC sends up the wrong S/W.<p><hr /></p></p></blockquote><br />Sounds familiar.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>As for Beagle, I guess your question depends on how the ESA runs their programs. Would they withold an important discovery? At this point, I guess only they know.<p><hr /></p></p></blockquote><br />MRO and Mars Express are both probably capable of imaging the MPL and Beagle 2 crash sites. The Deep Space 2 probes, though, are probably too small. <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]

Spirit is nearly dead now. Blame the amount of dust on the solar panels. Unlike Opportunity, it hasn't been lucky enough to be cleaned off by dust storms. Its power was only expected to last until Christmas -- and that was with them only driving every other day and shutting off some heaters to save power. Real shame as Spirit has finally found signs of water. <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>

 

[qso1]

To further clarify my statement. I don't mean to sound like a conspiracy theorist and had this question been asked about NASA, I'd have said highly unlikely NASA would withold any discoveries. But when asked this question about an agency we have little experience with...I can't answer that one with a high degree of confidence. Its my understanding the results of the Corot program are routinely witheld for months on end where in the U.S. we post it on the web the second it reaches us.<br /><br />IIRC, the crash site was imaged and I could not recall the specific craft that imaged it but the results were that they may have seen remains but are not 100% certain. I'd have to look it up. <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>

 

[brellis]

Here's another good one - NEAR <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[qso1]

Eventually, even the hardiest robotic spacecraft go dead, but NEAR...like many others, sent back some incredible images and data. <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>

 

[thalion]

<i>There's something very romantic about these intrepid spacecraft existing intact in (and out!) of our solar system. I think about the Huygens probe that landed on Titan. It was still transmitting when Cassini passed out of range. What did Huygens discover after that point, while it was still functioning? Maybe it started raining methane. It likely will rain at some point - the Titan monsoon season is coming.</i><br /><br />Good post. It does kind of get the creative juices flowing...for instance, in <i>The Cosmic Connection</i> (a kind of early, Cliff Notes version of <i>Cosmos</i>), Sagan writes about how when the Mariner 9 orbiter finally quit, that it still had some untransmitted imagery aboard, and speculates on the possibility of retrieving it someday. <img src="/images/icons/wink.gif" />