Talk:Parker Solar Probe

Fastest relative to what

What does it mean to be the "fastest" object when something is in space?

That is, speed relative to what? — Preceding unsigned comment added by 93.34.50.240 (talk) 08:40, 17 August 2012 (UTC)

Speed is measured relative to the inertial frame of reference of the moving object. For earth bound objects (including those in orbit around the Earth) that is the Earth itself. So you time the object between two points relative to the Earth. We tend to use the surface of the earth for convenience, but for accuracy and for use in space, the center of gravity of the Earth is the actual reference.

For a spacecraft, like Solar Probe, in the solar system, the inertial frame of reference is the Sun. So you use the time between two points relative to the center of the Sun. For Solar Probe, this is especially appropriate, since it will be "skimming" the surface of the Sun, so to speak. — Preceding unsigned comment added by Alan.A.Mick (talk • contribs) 02:03, 13 October 2013 (UTC)

SpaceNews dead link update (References #4)

Please update if this is the correct link. http://spacenews.com/41380solar-probe-plus-nasas-mission-to-the-fires-of-hell-trading-atlas-5-for/

BenjaminJMeyer (talk) 08:30, 2 January 2015 (UTC)

Materials, and spacecraft design

Of what materials is the Parker Solar Probe to be constructed? MaynardClark (talk) 17:59, 21 August 2017 (UTC)

Various different materials. I don't have to whole list. But that, as well as a description of the spacecraft and the instruments, should really be added to this page. Fcrary (talk) 18:03, 21 August 2017 (UTC)

Yes please. What propulsion does it have ? (any ion thrusters?)

What attitude control (thruster jets only, or also reaction wheels ?)

Does it have a steerable high gain antenna for communications ? When will it be out of contact ? Rod57 (talk) 10:09, 3 April 2018 (UTC)

In the March 2008 Mission Engineering Study Report it says

"Propulsion Hydrazine monopropellant 190 m/s ΔV

Attitude control Reaction wheels and thrusters

Telecommunications • Dual-frequency X-band and Ka-band through articulated HGA"

Rod57 (talk) 10:36, 3 April 2018 (UTC)

Can we have details on the design of SACS (Solar Array Cooling System)? What I have read so far is that it uses one gallon of water and there's a pump (not heat pipes). But how is the water kept from freezing when the spacecraft is far away from the Sun? Is it stored in a heated reservoir and the system is bled (possibly purging some filler gas?) once the probe gets close enough to the Sun for water not to freeze? Or perhaps it's naturally kept above freezing point at all times as it circulates in the exposed solar panels? And how is thermal expansion (of water) compensated for?

You can fry eggs on that thang! - overheard in Arkansas

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Relativistic effects?

I know relativity is needed to explain long term precession of Mercury. I'm curious if relativistic corrections are needed for a mission like that? Tom Ruen (talk) 19:45, 22 November 2017 (UTC)

I see the question here [1] Tom Ruen (talk) 19:46, 22 November 2017 (UTC)

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Radio link vs sun

Users of satellites on Earth have to deal seasonally with sun transit, when the satellite passes between the sun and the receiver, causing the satellite signal to be overwhelmed by the unmodulated but powerful output of the sun. How will Parker's signal be detected against this solar output? I am wondering if these close passes or the transmission time will occur when the probe is actually "beside" the sun, and not in front of it, that is, it is about to slip around the far side of the sun. GBC (talk) 17:54, 8 August 2018 (UTC)

The spacecraft has an elliptical orbit. Presumably, science data will be recorded near perihelion, and transmitted when it's farther away. Its aphelion remains outside the orbit of Venus, which is ample distance. 209.209.238.189 (talk) 08:49, 11 August 2018 (UTC)

A small point, but I understand that after the 7th Venus flyby, the aphelion will be slightly INSIDE the orbit of Venus. Anyway, I have seen a site--if I find it again, maybe I'll provide it-- showing the parts of the orbits where close solar observation will take place, and the parts where date will be transmitted to Earth. Uporządnicki (talk) 17:31, 24 October 2018 (UTC)

It's not useful for the article, but this is correct according to some of my colleagues who work on the project. Downlink of data and uplink of commands happen away from periapsis. I'm not sure if that's entirely due to solar noise; there may be thermal constraints involved in pointing an antenna at Earth. Around periapsis, they don't have any communications for a multi-day period (I think something like two weeks.) If someone can find a reference to this, it would be good to add to the article. Unfortunately, all I've got is a personal communication. Fcrary (talk) 20:33, 24 October 2018 (UTC)

This article https://www.researchgate.net/publication/301998540_SOLAR_PROBE_PLUS_MISSION_DESIGN_OVERVIEW_AND_MISSION_PROFILE goes into the question quite a bit. Basically, it says that the portion of each orbit closer to the Sun than 0.25 AU will be devoted to observation--the science phase. Once outside that portion of the orbit, the probe will be transmitting data to Earth. The article also goes into a fair bit of detail about some further considerations. While the angle--as measured from Earth--between the Sun and the probe is too small, communication will be limited or not possible. Furthermore, the probe needs to keep its heat shield pointed to the Sun, at least for parts of each orbit; there will be phases where that heat shield will block antennas from Earth and make communication impossible.

I'll leave it to others to decide what, from this source, is appropriate for the Wikipedia article, and how it should be presented and cited. Uporządnicki (talk) 16:50, 25 October 2018 (UTC)

Remove Voyager 2 plot?

There is currently a sidebar diagram showing Voyager 2 info, with the following caption:

   Plot of Voyager 2's heliocentric velocity against its distance from the Sun, illustrating the use of gravity assist to accelerate the spacecraft by Jupiter, Saturn and Uranus.[23] Using the same technique but with Venus, Parker Solar Probe will decelerate to lower its orbit.

This isn't really useful in this article; it feels like someone threw it in because it's available and somewhat related. Plus, Section 2 is really unbalanced at this point, with the sidebar being far taller than the body text.

Second flyby of Venus on December 22, 2019. The velocity decreases by 2.9 km/s to 26 km/s on December 26 (red circle), then the spacecraft enters a new orbit closer to the Sun.

Would it be appropriate to remove the diagram? -- Dan Griscom (talk) 13:04, 11 August 2018 (UTC)

I replaced the chart with a PSP flyby chart.―― Phoenix7777 (talk) 04:08, 13 August 2018 (UTC)

Great stuff. Could you perhaps try a version showing two Venus gravity slingshots and several intervening orbits? — JFG ^talk 15:27, 13 August 2018 (UTC)

I created a chart for a whole mission of PSP. See #Planned timeline.―― Phoenix7777 (talk) 12:26, 14 August 2018 (UTC)

Trajectory animation

Does anyone know how to fix the aspect ratio on the trajectory animation? Circular (or near circular) orbits ought to be shown as circular. The animation looks like the x:y scale is about 2:3, not 1:1. Fcrary (talk) 22:04, 12 August 2018 (UTC)

It is intentional. The animation is a view from (100, -100, 100) which means about 45 degree above X and -Y axis not a view from directly above.―― Phoenix7777 (talk) 22:19, 12 August 2018 (UTC)

I have no idea why someone would want to show trajectories from that angle. In any case, if that's what it is, the caption should say so. Fcrary (talk) 23:28, 12 August 2018 (UTC)

It is a default view of NASA JPL Small-Body Database Browser. I don't think such an explanation is needed.―― Phoenix7777 (talk) 23:52, 12 August 2018 (UTC)

Agree that the "default view" is fine. Certainly a clarification in the caption may help readers unfamiliar with Solar System animated views. — JFG ^talk 15:28, 13 August 2018 (UTC)

Planned timeline

Current two dimensional table is hard to read. A simple table like below is better.―― Phoenix7777 (talk) 04:00, 13 August 2018 (UTC)

Planned timeline

Year	Date	Events	Distance (million km)	Velocity (km/s)	Orbital period (day)
2018	Aug 12	Launch	–	–	–
	Sep 28	Venus flyby #1	–	–	–
	Nov 1	Perihelion #1	25	95	150
2019	Mar 31	Perihelion #2	25	95	150
	Aug 28	Perihelion #3	25	95	150
	Dec 21	Venus flyby #2	–	–	–
2020	Jan 24	Perihelion #4	20	109	130
	Jun 2	Perihelion #5	20	109	130
	Jul 6	Venus flyby #3	–	–	–
	Sep 22	Perihelion #6	14	129	112.5

• Support the change. Easier to read. Rowan Forest (talk) 04:04, 13 August 2018 (UTC)
• The intent of this table was to show the gradually reduced periodicity of the orbits, but I agree it doesn't do a great job of that. I spent a lot of time improving it and I'm still not satisfied. On the other hand, a simple 1D table would lose the intuitive timing information. I'm thinking of a graphical timeline view to replace all this. — JFG ^talk 15:25, 13 August 2018 (UTC)

I added an image for "a graphical timeline view". The table adds only exact dates of events and orbit periods. An editor moved the image to the bottom of the section. I can change the title of the image to "Timeline of Parker Solar Probe" if necessary.―― Phoenix7777 (talk)

Also the simple table can accommodate more information like above.―― Phoenix7777 (talk) 03:08, 14 August 2018 (UTC)

A graph of the velocity and distance from the sun of the probe from launch date until 2026. Legend: ①–㉔: Perihelion; ➊–➐: Venus Flyby

@Phoenix7777 and JFG: The nice graph above (which shows relative scales well) plus the 1-D table for details seems like the best solution to me.

My one complaint about the graph is that the labels are on the speed curve, with flybys at the bottom and perihelions at the top, which is somewhat unintuitive. Admittedly the flyby is visible on the speed curve and not on the distance curve. H'mmm. (Note that technically it's speed (a scalar quantity) and not velocity (a vector quantity) which is plotted.) 209.209.238.189 (talk) 12:02, 16 August 2018 (UTC)

P.S. I went ahead and made the change. Some perihelion speeds are missing from the table; I'm not sure where to find them. 209.209.238.189 (talk) 13:52, 16 August 2018 (UTC)

Looks good. I have updated the dates per source, taking into account the exact launch date. @Phoenix7777: perhaps you have access to the missing velocities, and to distances from the Sun during Venus flybys? — JFG ^talk 00:03, 17 August 2018 (UTC)

Thanks all of you, I filled out the speed.―― Phoenix7777 (talk) 05:54, 17 August 2018 (UTC)

@Phoenix7777: I see you added JPL Horizons as a source, but it's unclear how it can be queried to generate the necessary data. Can you build a URL that would enable a reader to WP:verify the information? Otherwise, we should find another source, or explain. Also, any chance to get the speeds at Venus, and possibly speed differentials imparted by the gravity assist? — JFG ^talk 06:56, 17 August 2018 (UTC)

@JFG: I used "HORIZONS Web-Interface" when I downloaded the data. Unfortunately any data download url is not available because HORIZEN employs cgi interface without reflecting all input parameters to its url. Moreover, when I downloaded the data, an available timespan was from 2018-Aug-11 to 2025-Aug-31. But JPL changed it from 2018-Aug-12 to 2018-Oct-10 after the launch. I tried to search SPICE data, but I couldn't find any data. So it is not verifiable now. If the downloaded data which was used to plot the graph is available, any information depicted in the graph including the flyby speed is available.

Anyway I created a url using a batch interface, but a timespan is only from 2018-Aug-12 to 2018-Oct-10.―― Phoenix7777 (talk) 09:46, 17 August 2018 (UTC)

@JFG: @209.209.238.189: HORIZONS Web-Interface now provides a revised data (Aug 24) from 2018-Aug-12 to 2025-Aug-31. Although the minimum time step size is 1 minute, the output length 3,709,503 exceeds 90,024 line max. So I created a url with a time step size of 1 hour.―― Phoenix7777 (talk) 22:42, 25 August 2018 (UTC)

Splendid. Is it possible from this data to fill in the blanks with distance and speed at the Venus flyby events? — JFG ^talk 08:02, 27 August 2018 (UTC)

Animation of Parker Solar Probe's trajectory around Venus from 12 August 2018 to 31 August 2025
   Parker Solar Probe ·   Venus

It is possible but distance and speed are meaningful only for perihelion. Flyby effect on speed may be of some help but distance of flyby may not add anything and only confuses readers.―― Phoenix7777 (talk) 10:17, 27 August 2018 (UTC)

If you mean the distance from and speed relative to the Sun, I guess you're right. But the approach (asymptotic) speed relative to Venus and the closest approach distance to Venus determine the magnitude of the gravity assist. I think there are also plans to take data during some of the Venus encounters. That's another reason the closest approach distance might be relevant. But if anyone puts that into the table, it ought to be in separate columns. Mixing it in with the solar range and speed would confusing.Fcrary (talk) 20:10, 27 August 2018 (UTC)

This url is Parker Solar Probe's data around Venus. I created an animation of Parker Solar Probe trajectory around Venus with curiosity.―― Phoenix7777 (talk) 21:02, 27 August 2018 (UTC)

I created a graph of Speed and distance of Parker Solar Probe relative to Venus. It seems hard to define "speed of flyby".―― Phoenix7777 (talk) 00:41, 28 August 2018 (UTC)

Speed and distance of Parker Solar Probe relative to Venus

This looks very interesting. Too much OR to place in the article, unfortunately, unless we find a report specifically discussing the probe's trajectory relative to Venus, then we could illustrate it with this animation. — JFG ^talk 07:29, 28 August 2018 (UTC)

Regarding the Venus gravity assists, I think it would be worthwhile to add extra columns showing speed and distance relative to Venus (+ perhaps Δv imparted), and still fine to list speed and distance relative to Sun in the existing column. — JFG ^talk 07:29, 28 August 2018 (UTC)

Well, the distance from Parker to the Sun at the Venus passes would be almost exactly the distance from Venus to the Sun; the Venus passes are planned to be anywhere from a couple of hundred to a couple of thousand miles from Venus--an infinitesimal amount in the scale of things. And the orbit Venus, conveniently, is the least eccentric among all the planets--meaning it's the least oval-shaped. In fact it departs only slightly from being a mathematically perfect circle with the Sun at the center. So its distance from the Sun is always pretty much the same.

What I've been searching the Internet for is aphelion figures--the far distances. The Venus encounters generally will NOT take place at aphelion. The aphelia of each group of orbits following each pass of Venus will be the same. As I understand it, the aphelia after the first and second pass will be near the orbit of Earth, almost but a little less than 1 AU. The next several passes will result in aphelia progressively closer to, but outside of, the orbit of Venus. And finally, the last pass will bring about an orbit with aphelion a little inside the orbit of Venus--and there will be no more passes. But I can't find a good, definitive source for this. I've gleaned it from diagrams here and there, and I've seen various sources that hint at parts of it. There's a source cited in the article; it's a large page of numbers that one can apparently use to construct the orbits in detail. Contributors here have been using it, but it's way beyond my tech skill set. Uporządnicki (talk) 13:13, 27 October 2018 (UTC)

I'm afraid I have to disagree with myself. I just realized that SPP is only making Venus encounters and I don't think any major maneuvers are planned. In that case, there is a conservation law which applies and the approach velocity to Venus will be essentially the same on all encounters. That wouldn't be worth giving its own column in the table. Simply stating the number in the text would be sufficient along with the range at which it was calculated (I think the Sphere of Influence is the traditional distance.) For the table, I now think it would be best to simply add a column for the closest approach distance on Venus encounters. Fcrary (talk) 01:08, 29 August 2018 (UTC)

I think it's not correct that the approach velocity to Venus will be essentially the same on all encounters. There are two reasons. First, the encounters in general will NOT happen at Parker's aphelion. Some will happen on its way out to aphelion; some on its way back in. That aphelion will change with each encounter of course--the very purpose of the encounters is to change Parker's perihelion, which will necessarily change the aphelion. The second reason might make only a trivial difference; the passes will happen at various distances from Venus--from several thousand to just a couple of hundred miles. Of course, as Parker approaches Venus, it will be sped up; as it moves away, it will be slowed down. And its trajectory will be altered. I'm supposing that effect will be greater for the close passes.

I've found a couple of good places with information on the individual passes; I'm contemplating adding that information, as soon as I figure out how to cite it properly (my Wikipedia editing to date has involved almost no citation). That information does not include speed of passes, but I'm not sure how interesting that really is. Uporządnicki (talk) 13:42, 27 October 2018 (UTC)

To the extent that the assumptions of the restricted three body problem apply, the approach speed to Venus (and the departure speed after the encounter) are conserved quantities. Those assumptions are that the spacecraft's mass is negligible compared to that of Venus and the Sun (a very good approximation), that the orbit of Venus is circular (it's 0.007) and that only the gravity of the Sun and Venus matter (rocket firings and distant perturbations from other planets cause slight variations.) It doesn't matter where along the spacecraft's orbit the encounter occurs, not does the eccentricity of the spacecraft's orbit. Fcrary (talk) 20:20, 27 October 2018 (UTC)

I'd already worked out that when I went into the business about the eccentricity of Venus, I'd misread the original posting I was responding to. I thought someone proposed adding date on the distance to the Sun at the various Venus passes; I was mistaken.

Now, it does seem to me kind of obvious that when the spacecraft is flying past Venus those seven times, it would necessarily be flying at different speeds. But you clearly have more expertise in this than I have. I have to conclude that "approach speed" has some--no doubt rigorously defined--meaning that I'm not aware of. Uporządnicki (talk) 20:47, 28 October 2018 (UTC)

It's all a question of what the speed is relative to. On the different encounters, the spacecraft is approaching (and departing from) Venus at essentially the same speed. But it's approaching from a different direction. That means the spacecraft's speed relative to the Sun, rather than Venus, is different. Initially, it's moving faster than Venus. Later, it's moving slower. Relative to the Sun. Fcrary (talk) 23:49, 28 October 2018 (UTC)

Flight Software

The page discusses the instruments without mention of the flight software itself. The Flight Software Workshop by Christopher Krupiarz (http://flightsoftware.jhuapl.edu/files/2015/Day-1/SolarProbePlusOverviewFINAL.pptx) gives detailed information on the LEON3 flight hardware, software requirements, and functionality. It includes great information on the software architecture noting the it uses RTEMS, OSAL, and the Core Flight Executive along with the "lollipop" diagram of mission functionality attached to the cFE. It would be nice to get a section on the flight software in the page. Any thoughts on where it might go? --JoelSherrill (talk) 15:23, 14 August 2018 (UTC)

I was thinking that the article can be improved if we create a section on the spacecraft's development and construction, especially its radiation and thermal protection, as well as its cooling systems. The flight software can surely be a part of this new section. Cheers, Rowan Forest (talk) 03:06, 15 August 2018 (UTC)

I've got mixed feelings about that. Are we trying to describe what they built or how they built it? A section on development and construction sounds like it would cover things like the design reviews and testing, as much as the hardware (and software) itself. If we want to describe the spacecraft itself, we already have a section on the spacecraft. We could significantly expand that. Either way is fine with me; I'd just like the keep the section title and contents consistent. Fcrary (talk) 21:06, 15 August 2018 (UTC)

Yesterday I gathered that Spacecraft section together. I am not proposing to include design reviews and testing. Most of it is there, just missing software and radiation protection (high energy particles). Cheers, Rowan Forest (talk) 00:51, 16 August 2018 (UTC)

Costs

How much did that probe cost? — Preceding unsigned comment added by 78.49.247.38 (talk) 09:19, 15 August 2018 (UTC)

I added it. (US$1.5 billion). Cheers, Rowan Forest (talk) 01:01, 16 August 2018 (UTC)

That "Error" in the table.

@Mfb: Re:your edit, FYI that was caused by a change in column heading. It was originally perihelion distance, and was accurate for the launch orbit. (But of course, the spacecraft was nowhere near perihelion; it launched from 1.0 AU, not 0.278.) I changed the column heading to "perihelion" to help untangle the frequent confusion in various sources between distance-from-Sun-center and altitude-above-Sun-surface. I thought using "perihelion" for the former and "altitude" for the latter and avoiding the ambiguous word "distance" entirely was the way to go.

Then someone changed it back to "distance" and that resulted in the mess you dealt with. 209.209.238.189 (talk) 01:09, 18 August 2018 (UTC)

Ah, I didn't check the page history. I just saw it in that state and fixed the value that was wrong. --mfb (talk) 01:28, 18 August 2018 (UTC)

I changed the header to "Distance from Sun" because this table documents several events other than perihelions, namely the launch and the Venus flybys, and we may add other events later, e.g. some of the aphelions. I failed to correct the value, thanks mfb. We should now fill in the missing distances according to the predicted dates for gravity assist maneuvers at Venus. I don't think there's any case for listing the "altitude from Sun surface" metric; that's best reserved for the article text, when discussing "how close" the probe will pass such "surface". — JFG ^talk 04:23, 18 August 2018 (UTC)

@Mfb: You're not obliged to check edit history every freaking time. As you say, fixing what's wrong is the important thing. I just thought I answer the "WTF?" subtext I heard in your edit comment.

@JFG: I'm not trying to make a big deal about it; it's just that a heck of a lot of the non-technical reports about the probe quote altitude and it can be very confusing. I wish there were a simple word like "altitude" that unambiguously meant distance-between-centers-of-mass. Another hard-to-untangle datum is the final perihelion; an awful lot of design documents quote 9.5 R_☉. But maybe now it's 9.86 R_☉? That's why I added the note about the fact that it's not determined yet.

What I do wonder is why you removed the "bold=completed" convention from the table. Too much work to keep up to date in the future? 209.209.238.189 (talk) 10:37, 18 August 2018 (UTC)

Bold was just unnecessary; readers know the current date. — JFG ^talk 14:29, 18 August 2018 (UTC)

My downloaded data from HORIZONS says the last three perihelion is 6.863, 6.862, 6.864 million km center to center. So it is 9.86 R_☉.―― Phoenix7777 (talk) 11:46, 18 August 2018 (UTC)

Storage card, not memory card.

The third paragraph which begins "A memory card containing the names of over 1.1 million people..." seems incorrect. It should be "A data storage card containing the names of over 1.1 million people..."

In cyber technology memory is a volatile data container (does not retain data when powered off) whereas storage is a nonvolatile data container (retains data even when powered off). I presume the device is in fact a storage card sans confirmation, but very strongly believe my presumption is accurate - no even partially competent circuit or systems engineer would entrust such data to a volatile device, nor have any technical or economic reason to do so.

Please comment if you disagree or have additional perspective. Otherwise I'll make the change in about a week. Cheers! --H Bruce Campbell (talk) 16:52, 18 August 2018 (UTC)

We know what a memory card is, and it's non-volatile. The term "memory" does not imply volatile storage; ever hear of flash memory? (Or core memory, read-only memory, drum memory, etc.) Wikipedia has a whole article on different types of non-volatile memory. Nor does "storage" imply the non-volatile; the term "volatile storage" I used in my second sentence is also common in the field.

It's quite obvious that the storage medium is non-volatile; that's implied by "card" (meaning removable/transportable) and the fact that there would be little point otherwise. "Data storage" does not make that implication stronger, and given that it makes the phrasing more labored and awkward, I oppose the change. 209.209.238.189 (talk) 12:56, 19 August 2018 (UTC)

I could quibble about how, technically, a "memory card" can mean a circuit board populated with volatile memory chips... But that's irrelevant. As you say, it can also mean non-volatile memory.

A more important point (to me) is that the NASA and APL press releases consistently call this thing a "memory card." Debating whether or not they are using the term correctly doesn't matter. The Wikipedia article needs to go with the sources, not the editors' interpretations and opinions. Fcrary (talk) 19:25, 19 August 2018 (UTC)

I defer to the valid element of Fcrary's point - I'll make no change at this time. But I defer very reluctantly, and in spirit only partially, because:

I disagree with 209.209.238.189 because in my experience in the history and evolution of these technology sectors memory and storage are strictly defining terms. Yes misuse is common, but it's in the long evolutionary process of being corrected by more broad acceptance and use of the correct terms. That is, in cyber technology the correct term for a volatile data container is memory, and for a non-volatile container storage. Frequent misuse isn't justification for continued misuse - 'can mean' can be cited to try to justify any erroneous rhetoric, but it's an empty and counterproductive justification which perpetuates chaotic and confusing communication.

The industry is slowly advancing the proper terms into more popular and disciplined use - fabrication firms particularly are increasingly more rigorous about this (in spite of Toshiba's lingering corporate division name mistake, which in my estimation is rooted in a combination of a translation error from long ago and the earlier much weaker rhetorical discipline, but will ultimately be corrected too). And in my view the process should be supported. I don't suggest Wikipedia should be the primary force behind this long process of language refinement, but neither should it resist and thus oppose productive change.

And therein lies a significant challenge since, as 209.209.238.189 cites, numerous Wikipedia references are conflicted and confused about the terminology and thus adding potholes to the road to clean and clear rhetoric which technologists and the industry are advancing. And though a daunting challenge, in my view Wikipedia should join the global process toward clean and clear terminology - numerous Wikipedia pages need an enlightened process of patient but clearly focused change to contribute, or at least be in line with, the process of change to popular use of the correct terminology.

People frequently referred to dolphins as fish. And not so long ago... A process of enlightened language refinement largely eliminated that misuse. The same terminology refinement process is slowly occurring with memory and storage technology, and in my view Wikipedia should rationally support or at least not oppose this productive evolution. In time we'll look back in wonder that anyone ever referred to storage as memory or memory as storage, just as we now perceive it as remarkably ignorant that people frequently referred to sea mammals as fish in earlier times.

And this is no small matter as AI, leading to ASI (evolved Strong AI), are storage intensive and, in my view, soon to become storage insatiable technologies. And will very likely swiftly become key defining features of life on this planet. --H Bruce Campbell (talk) 16:44, 26 August 2018 (UTC)

That's why I like sticking to the terms and names used in the source material. If we do so, your concern will automatically be taken care of. Once people (i.e. the source material) adopt consistent terminology, then accepting their usage will be consistent. On the other hand, it's quite possible people will adopt some completely different, but consistent terminology. However, until then, we are linking to the article on Memory card and it doesn't seem to say anything about terminology or volatile versus nonvolatile storage. That might be the right place to note the issue about terminology and consistent usage. Fcrary (talk) 19:10, 26 August 2018 (UTC)

Thanks Fcrary. We might differ in some modest measure but I respect your perspective, and especially agree that the Memory card article is the most suitable place to consider the matter further. If time permits... --H Bruce Campbell (talk) 07:59, 27 August 2018 (UTC)

Animation of orbits--slow? pause?

That animation of the orbits is very interesting. But I wonder if there's a way to slow it down here and there, or pause it. Uporządnicki (talk) 17:26, 24 October 2018 (UTC)

@AzseicsoK: There is a 50 Mpx restriction for gif files in Commons. So the maximum frame count is 212 for this file. (50 Mpx / (560 px x 420 px) = 212 frames) It is possible to make gif delay from 10 ms to 20 ms. But it is hard to see. So I created a webm video with 600 frames. I don't want replace the gif file with this webm file because it requires readers action to enable the file. So I added a link to the webm file for interested readers.―― Phoenix7777 (talk) 23:50, 24 October 2018 (UTC)

I don't understand what you've said here, but no matter; I love what you've done. Thanks!

I'm old enough to have watched a single still image sent via satellite (I think it was Telstar) being built one line at a time on our old Zenith black and white (VHF only); I followed the Mercury program (although at that age, I wasn't paying a lot of attention to detail; John Glenn went around three times, that's about as in depth as I got). After the moon landing, Parker, Voyager, and New Horizons to Pluto (I met Clyde Tombaugh once) are, for me, about the most exciting things NASA has done. Uporządnicki (talk) 16:20, 29 October 2018 (UTC)