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I agree that it makes sense for Yenisey-2 to be merged into this article. ThreeBlindMice 20:12, 14 September 2006 (UTC)
Upon complete reading of this article I'd say that most of the information contained in Yenisey-2 is already included here under Lunar Photography. Thus, merging the remaining information from Yenisey-2 seems the obvious thing to do. ThreeBlindMice 20:18, 14 September 2006 (UTC)
Merging was the proper thing to do. The Yenisey-2 system was used only on the Luna 3 mission so it was unnecessary to have a separate, common article for other missions to link to. A Stand Up Guy 15:37, 18 September 2006 (UTC)
Apoastron and periastron are incorrect terms, as the sattelite was orbiting Earth, not a star. Apogee and perigee are the correct terms. 203.143.164.204 04:49, 28 August 2007 (UTC)
Much of the body of this article has been plagiarised from http://nssdc.gsfc.nasa.gov/nmc/masterCatalog.do?sc=1959-008A. If someone could paraphrase the text so that this isn't an issue?? 130.217.188.28 ( talk) 04:12, 6 December 2007 (UTC)
The launch time is wrong (for many space probes!). Here's what happens. The RAE table lists the launch time of Luna-3 as "Oct 4.1". If you convert the one-digit approximage time ".1 days" to four digits of accuracy, you get 02:24 UT. Wrong. The actual launch date for Luna-3 was 00:43:39.7 UT (given by Baikonur telemetry specialist and historian, Vladimir Poroshkov). I'll edit in, but it's likely to get undone someday, because the NASA website is mistaken. DonPMitchell ( talk) 07:28, 31 August 2008 (UTC)
I think this page is unfairly biased towards the Russian space exploits! AN objective page would include several mentionings of the achievements of FREEDOM. 63.214.229.68 ( talk) 22:05, 18 January 2009 (UTC)
I can't believe there aren't any pics from this mission on this page. If I have time, I'll go find some. fvincent ( talk) 17:25, 10 December 2010 (UTC)
There are none in Commons, but there are in Google Images. Bubba73 You talkin' to me? 06:40, 21 December 2011 (UTC)
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This article has a section which states:
The most obvious problem with this statement is that gravity assist is not being "used" when flying out to the Moon to take images. Gravity assist is used by virtue of what happens after a probe encounters the gravity well of another body. So if it is used at all on this mission, it would have to be something that happened after it flew away from the Moon. And this is the larger point. I have not looked deeply into this, but just from basic info about this mission, I don't see anything useful that was done as a necessary result of this probes' trajectory having been altered by its encounter with the Moon's gravity well. The only way it can properly be considered a "gravity assist" is if that gravity effect was used to actually assist in doing anything. I see nothing here. Nothing at all.
Yes, its trajectory was altered by the Moon's gravity. But this claim to being the "first gravity assist" needs to be removed, unless anyone can support this view with a sound argument. And there should also be verifiable sources which present the same kind of claim and supporting argument.
From the totality of everything I know about this, I see absolutely no basis for this statement. Best I can tell, the gravity-induced trajectory change was merely incidental, and obviously unavoidable. But had absolutely nothing to do with the mission's primary objective. And I don't see any secondary or other objective from this mission which required this trajectory change. So the clear conclusion is that "gravity assist" was not used. Nothing useful was derived out of it.
Now the changed direction may have incidentally brought the probe closer to Earth during its leg after leaving the Moon. But if all it was doing was sending signals, and those signals could have been received just as easily as if the probe did not get changed to this course bringing it closer, then no practical benefit was derived from having its path coming back toward Earth being closer rather than further. The results of the mission would have been the same if the return leg had been further away, because the transmission signals don't care about the distance. So long as there is sufficient power in the transmitter, the only impact is an insignificantly shorter transmission time. So here too, the gravity-induced change in trajectory was not used for any mission benefit. Gravity was not used to assist.
I am open to the possibility that I am missing something very basic. And if anyone knows of any reason why this was indeed a legitimate use of gravity assist, I would be very interested to learn about that. But if no one can do that, then this needs to be removed.
At most, from what I see here, the best statement to be made for Luna 3 is that this mission is the first time that the gravity well of another celestial body caused a significant trajectory change for a space probe. But again, if that change is not used for anything productive, then it is not a gravity assist.
As far as I can tell, this is a bogus claim. -- Tdadamemd19 ( talk) 07:21, 14 July 2019 (UTC)
Actually, the sources are already there. I probably shouldn't have called them vague. They are actually quite specific. In the referenced book, Essential Spaceflight Dynamics and Magnetospherics, it says,
"Gravity-assist maneuvers are widely, and effectively, used for interplanetary missions. The first time such a maneuver was realized was during the flight of the Soviet SC Luna-3 in 1959... The simple transfer trajectory shown in Fig. 12.5 presents an obvious candidate orbit... In 1959 a disadvantage of this trajectory was that, in returning from to the Earth, the SC would approach from the South and count not... be contacted from the territory of the former Soviet Union. To overcome this a trajectory was chosen involving a gravity-assist maneuver." (Emphasis added and ellipsises are mostly skipping references to a figure.)
That book, by the way, is published by Kluwer Academic Publishers, which is a reputable source. Not that the source specifically states that an alternative trajectory was chosen, to avoid a problem another trajectory would have had.
One of the other references looks like a short biography of M. V. Keldysh, off the web site of the Keldysh Institute of Applied Mathematics. That's a less ideal source, since they are probably a little biased. But no worse than many sources cited on Wikipedia. That states (although I had to use Google Translate, since it's in Russian):
"Initially, the main efforts were aimed at solving the problem of reaching the moon and exploring the near-moon space. The relevant work was carried out in a short time under the general guidance of M.V. Keldysh. A brilliant example of work from the "lunar" cycle was the choice of flight paths and photographing the invisible side of the moon for the Luna-3 satellite. Here, for the first time in world practice, a "gravitational maneuver" was proposed and successfully implemented - a purposeful change in the trajectory of a spacecraft as a result of perturbation of its motion by a celestial body (the Moon)." (Again, emphasis added.)
So we've got two references saying the trajectory was a choice, not a fortunate coincidence, one saying the change to the trajectory was "purposeful" and the other saying it allowed telecommunications coverage where other trajectories would not. I haven't seen anything other than your assertions to contradict those references. Fcrary ( talk) 22:51, 1 August 2019 (UTC)
--------
To better analyze the merits of this claim, it will help to look at the exact quote from the reference that was provided:
What this is describing is merely accounting for the trajectory alteration, and then planning the trajectory in a way which makes for convenient communications. This is categorically distinct from taking advantage of the free delta-v imparted by the encounter with the celestial body. The argument for removal is that this is an adulteration of the typical meaning of the usage of the term "gravity assist" in regards to spacecraft mission design. What the planners of Luna 3 apparently did was adapt to the unavoidable trajectory alterations which resulted from the lunar encounter so that their communications plan worked more effectively.
Making plans so that your communications still work conveniently after the trajectory change is not a "gravity assist". This would be better described as a "mission plan adaptation to the unavoidable gravity-induced trajectory change". The planners tweaked their trajectory in order to accommodate for the delta-v change. Not for the purpose of taking advantage of a propellant-free maneuver.
A key consideration for what gets done with the article here is whether there are any sources other than this book which makes the same claim regarding Luna 3, and more importantly, whether their basis for such a claim is just as weak as the one presented in this book. -- Tdadamemd19 ( talk) 07:57, 14 July 2019 (UTC)
This might be a much easier way to show how bogus this claim is...
The purpose of this mission was to fly out to lunar distance and take photographs of the Moon. Now consider a hypothetical where the Moon is an object of very little mass. It would not alter Luna 3's trajectory in any significant way. A probe can fly out there, take pictures of this object, and fly back on an essentially unaltered elliptical trajectory. Because of this hypothetical, the mission's path now becomes a two-body problem, no longer a three-body problem.
So the question becomes this: In such a hypothetical case, would the mission planners want to have additional thrust made available for their probe so that its mission objectives can be improved? A delta-v that would assist this mission?
It is clear to me that the answer to this is 'no'. Adding thrust upon passing the Moon gives no advantage to the mission objectives whatsoever.
Now flip a switch which turns lunar gravity back on, and all this does for the mission planners is complicate their work. It gives them no advantage. It produces no "assist". Lunar gravity, for the case of Luna 3, can be understood as having been a nuisance which complicated their planning calculations. It was in no way an "assist". This argument might be the clearest way to illustrate that calling Luna 3 a "gravity assist" mission is an utterly bogus claim. If the mission planners for Luna 3 had a switch that had the ability to turn lunar gravity off, and it can be clearly seen that this would have made their job much easier, then it is completely improper to say that they used the lunar gravity to assist in achieving their mission objectives.
This stands in stark contrast to bona fide gravity assist missions where the mission could not have been accomplished were it not for this free delta-v infusion. Or it would have required a significantly bigger rocket at a significantly bigger expense. The essence of gravity assist is that you are using gravity to assist you. Whoever concocted this notion that this qualifies as anything that happened with Luna 3 has lots of 'splaining to do. I myself see absolutely no justification for this claim. -- Tdadamemd19 ( talk) 08:35, 14 July 2019 (UTC)
![]() | This ![]() It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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![]() | A fact from this article was featured on Wikipedia's Main Page in the On this day section on October 7, 2007. |
I agree that it makes sense for Yenisey-2 to be merged into this article. ThreeBlindMice 20:12, 14 September 2006 (UTC)
Upon complete reading of this article I'd say that most of the information contained in Yenisey-2 is already included here under Lunar Photography. Thus, merging the remaining information from Yenisey-2 seems the obvious thing to do. ThreeBlindMice 20:18, 14 September 2006 (UTC)
Merging was the proper thing to do. The Yenisey-2 system was used only on the Luna 3 mission so it was unnecessary to have a separate, common article for other missions to link to. A Stand Up Guy 15:37, 18 September 2006 (UTC)
Apoastron and periastron are incorrect terms, as the sattelite was orbiting Earth, not a star. Apogee and perigee are the correct terms. 203.143.164.204 04:49, 28 August 2007 (UTC)
Much of the body of this article has been plagiarised from http://nssdc.gsfc.nasa.gov/nmc/masterCatalog.do?sc=1959-008A. If someone could paraphrase the text so that this isn't an issue?? 130.217.188.28 ( talk) 04:12, 6 December 2007 (UTC)
The launch time is wrong (for many space probes!). Here's what happens. The RAE table lists the launch time of Luna-3 as "Oct 4.1". If you convert the one-digit approximage time ".1 days" to four digits of accuracy, you get 02:24 UT. Wrong. The actual launch date for Luna-3 was 00:43:39.7 UT (given by Baikonur telemetry specialist and historian, Vladimir Poroshkov). I'll edit in, but it's likely to get undone someday, because the NASA website is mistaken. DonPMitchell ( talk) 07:28, 31 August 2008 (UTC)
I think this page is unfairly biased towards the Russian space exploits! AN objective page would include several mentionings of the achievements of FREEDOM. 63.214.229.68 ( talk) 22:05, 18 January 2009 (UTC)
I can't believe there aren't any pics from this mission on this page. If I have time, I'll go find some. fvincent ( talk) 17:25, 10 December 2010 (UTC)
There are none in Commons, but there are in Google Images. Bubba73 You talkin' to me? 06:40, 21 December 2011 (UTC)
Hello fellow Wikipedians,
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The following Wikimedia Commons file used on this page has been nominated for deletion:
Participate in the deletion discussion at the nomination page. — Community Tech bot ( talk) 06:51, 15 May 2019 (UTC)
This article has a section which states:
The most obvious problem with this statement is that gravity assist is not being "used" when flying out to the Moon to take images. Gravity assist is used by virtue of what happens after a probe encounters the gravity well of another body. So if it is used at all on this mission, it would have to be something that happened after it flew away from the Moon. And this is the larger point. I have not looked deeply into this, but just from basic info about this mission, I don't see anything useful that was done as a necessary result of this probes' trajectory having been altered by its encounter with the Moon's gravity well. The only way it can properly be considered a "gravity assist" is if that gravity effect was used to actually assist in doing anything. I see nothing here. Nothing at all.
Yes, its trajectory was altered by the Moon's gravity. But this claim to being the "first gravity assist" needs to be removed, unless anyone can support this view with a sound argument. And there should also be verifiable sources which present the same kind of claim and supporting argument.
From the totality of everything I know about this, I see absolutely no basis for this statement. Best I can tell, the gravity-induced trajectory change was merely incidental, and obviously unavoidable. But had absolutely nothing to do with the mission's primary objective. And I don't see any secondary or other objective from this mission which required this trajectory change. So the clear conclusion is that "gravity assist" was not used. Nothing useful was derived out of it.
Now the changed direction may have incidentally brought the probe closer to Earth during its leg after leaving the Moon. But if all it was doing was sending signals, and those signals could have been received just as easily as if the probe did not get changed to this course bringing it closer, then no practical benefit was derived from having its path coming back toward Earth being closer rather than further. The results of the mission would have been the same if the return leg had been further away, because the transmission signals don't care about the distance. So long as there is sufficient power in the transmitter, the only impact is an insignificantly shorter transmission time. So here too, the gravity-induced change in trajectory was not used for any mission benefit. Gravity was not used to assist.
I am open to the possibility that I am missing something very basic. And if anyone knows of any reason why this was indeed a legitimate use of gravity assist, I would be very interested to learn about that. But if no one can do that, then this needs to be removed.
At most, from what I see here, the best statement to be made for Luna 3 is that this mission is the first time that the gravity well of another celestial body caused a significant trajectory change for a space probe. But again, if that change is not used for anything productive, then it is not a gravity assist.
As far as I can tell, this is a bogus claim. -- Tdadamemd19 ( talk) 07:21, 14 July 2019 (UTC)
Actually, the sources are already there. I probably shouldn't have called them vague. They are actually quite specific. In the referenced book, Essential Spaceflight Dynamics and Magnetospherics, it says,
"Gravity-assist maneuvers are widely, and effectively, used for interplanetary missions. The first time such a maneuver was realized was during the flight of the Soviet SC Luna-3 in 1959... The simple transfer trajectory shown in Fig. 12.5 presents an obvious candidate orbit... In 1959 a disadvantage of this trajectory was that, in returning from to the Earth, the SC would approach from the South and count not... be contacted from the territory of the former Soviet Union. To overcome this a trajectory was chosen involving a gravity-assist maneuver." (Emphasis added and ellipsises are mostly skipping references to a figure.)
That book, by the way, is published by Kluwer Academic Publishers, which is a reputable source. Not that the source specifically states that an alternative trajectory was chosen, to avoid a problem another trajectory would have had.
One of the other references looks like a short biography of M. V. Keldysh, off the web site of the Keldysh Institute of Applied Mathematics. That's a less ideal source, since they are probably a little biased. But no worse than many sources cited on Wikipedia. That states (although I had to use Google Translate, since it's in Russian):
"Initially, the main efforts were aimed at solving the problem of reaching the moon and exploring the near-moon space. The relevant work was carried out in a short time under the general guidance of M.V. Keldysh. A brilliant example of work from the "lunar" cycle was the choice of flight paths and photographing the invisible side of the moon for the Luna-3 satellite. Here, for the first time in world practice, a "gravitational maneuver" was proposed and successfully implemented - a purposeful change in the trajectory of a spacecraft as a result of perturbation of its motion by a celestial body (the Moon)." (Again, emphasis added.)
So we've got two references saying the trajectory was a choice, not a fortunate coincidence, one saying the change to the trajectory was "purposeful" and the other saying it allowed telecommunications coverage where other trajectories would not. I haven't seen anything other than your assertions to contradict those references. Fcrary ( talk) 22:51, 1 August 2019 (UTC)
--------
To better analyze the merits of this claim, it will help to look at the exact quote from the reference that was provided:
What this is describing is merely accounting for the trajectory alteration, and then planning the trajectory in a way which makes for convenient communications. This is categorically distinct from taking advantage of the free delta-v imparted by the encounter with the celestial body. The argument for removal is that this is an adulteration of the typical meaning of the usage of the term "gravity assist" in regards to spacecraft mission design. What the planners of Luna 3 apparently did was adapt to the unavoidable trajectory alterations which resulted from the lunar encounter so that their communications plan worked more effectively.
Making plans so that your communications still work conveniently after the trajectory change is not a "gravity assist". This would be better described as a "mission plan adaptation to the unavoidable gravity-induced trajectory change". The planners tweaked their trajectory in order to accommodate for the delta-v change. Not for the purpose of taking advantage of a propellant-free maneuver.
A key consideration for what gets done with the article here is whether there are any sources other than this book which makes the same claim regarding Luna 3, and more importantly, whether their basis for such a claim is just as weak as the one presented in this book. -- Tdadamemd19 ( talk) 07:57, 14 July 2019 (UTC)
This might be a much easier way to show how bogus this claim is...
The purpose of this mission was to fly out to lunar distance and take photographs of the Moon. Now consider a hypothetical where the Moon is an object of very little mass. It would not alter Luna 3's trajectory in any significant way. A probe can fly out there, take pictures of this object, and fly back on an essentially unaltered elliptical trajectory. Because of this hypothetical, the mission's path now becomes a two-body problem, no longer a three-body problem.
So the question becomes this: In such a hypothetical case, would the mission planners want to have additional thrust made available for their probe so that its mission objectives can be improved? A delta-v that would assist this mission?
It is clear to me that the answer to this is 'no'. Adding thrust upon passing the Moon gives no advantage to the mission objectives whatsoever.
Now flip a switch which turns lunar gravity back on, and all this does for the mission planners is complicate their work. It gives them no advantage. It produces no "assist". Lunar gravity, for the case of Luna 3, can be understood as having been a nuisance which complicated their planning calculations. It was in no way an "assist". This argument might be the clearest way to illustrate that calling Luna 3 a "gravity assist" mission is an utterly bogus claim. If the mission planners for Luna 3 had a switch that had the ability to turn lunar gravity off, and it can be clearly seen that this would have made their job much easier, then it is completely improper to say that they used the lunar gravity to assist in achieving their mission objectives.
This stands in stark contrast to bona fide gravity assist missions where the mission could not have been accomplished were it not for this free delta-v infusion. Or it would have required a significantly bigger rocket at a significantly bigger expense. The essence of gravity assist is that you are using gravity to assist you. Whoever concocted this notion that this qualifies as anything that happened with Luna 3 has lots of 'splaining to do. I myself see absolutely no justification for this claim. -- Tdadamemd19 ( talk) 08:35, 14 July 2019 (UTC)