Talk:Spacecraft flight dynamics

Mergeto

I think this page can be merged into a more general topic of Attitude_dynamics_and_control s1 17:11, 6 May 2007 (UTC)

• Attitude control is a much older and more comprehensive article199.172.246.196 17:59, 20 July 2007 (UTC)
  • I merged them yesterday, thought I had already left this comment but when I checked if people had replyed... I hadn't - File:FireFlames.jpgYes, I really am a Sith Lord ^(Comms) 17:52, 15 August 2007 (UTC)

Undoing redirection from Attitude control

I suggest undoing the redirection of Attitude control to this article. Since the redirection and merge, this article has not been expanded to include any dynamics per se. Without having that material, the former name better applies to the current content. (sdsds - talk) 02:39, 8 September 2007 (UTC)

• i think it would be a better idea to leave the redirect and merge, and to just request an expantion on the dynamics of it File:FireFlames.jpgYes, I really am a Sith Lord ^(Comms) 18:21, 10 September 2007 (UTC)

Expanding and stressing on spacecraft attitude control

It starts:

Attitude control is control of the orientation of a ships, spacecraft, or other flight vehicle, either relative to the celestial sphere or to a gravitating body influencing its flight path.

In reality the article is about spacecraft attitude control. The "attitude control of ships" is for example quite another matter (automatically because of the shape of the body floating on the water, the compass for the heading).

For spacecraft the main split should be "spin stabilized" versus "3 axis stabilized". The last term is not even mentioned!

For "3 axis stabilized" the term "slew" should be explained! Another article would like to have a reference to "slew"!

Stamcose (talk) 15:22, 26 July 2008 (UTC)

I agree, and would support almost any edit that modifies the article in the ways you describe. Specifically, this article should be about the techniques used to maintain and alter the attitude of a spacecraft, and the reasons why it is important to do so. The specific components of an attitude control system would be better discussed in that article than in this one. Can we come up with a proposal on how to restructure the article (i.e. change the sections around) so future content edits are more likely to take it in the right direction? (sdsds - talk) 22:07, 26 July 2008 (UTC)

Duality between Flight dynamics (aircraft) and Flight dynamics (satellites)

I have added an {{otheruses}} template to more clearly help readers get to the correct flight dynamics article. However, I think there is a substantial amount of decent material included in the Flight dynamics (aircraft) article that should be, at minimum, looked at for ideas of what ought to be included to improve this article. In saying this, I do not mean all the technical equations and calculus, but I do think that clear understanding of pitch, yaw, roll and translation for the lay reader would be as helpful here as it is in the aircraft article. Probably some other ideas as well. What do other editors observe might be helpful? I will do some work to look for graphics that might help as well. N2e (talk) 03:51, 13 December 2010 (UTC)

Article needs some graphics

This article would greatly benefit from some simple graphics, aimed for the lay reader, to assist the reader to grok pitch, yaw, roll, and translation for a generic spacecraft vehicle. As a starting point, I'm thinking something like the four graphics in the Flight dynamics (aircraft) article, only without all the aerodynamic surfaces, and with some sort of a generic spacecraft object inserted in lieu of the aircraft shown. N2e (talk) 04:15, 13 December 2010 (UTC)

I will add a {{reqimage}} tag to help out.

I have placed a request for assistance from some of the graphic mavens over at Wikimedia commons on each of the file pages for the four source pages for the four main graphics in the Flight dynamics (aircraft) article. If you want to see an example, go here. N2e (talk) 04:56, 13 December 2010 (UTC)

I had the same needs on WP:fr, and I have done some graphics you can see on fr:Reaction Control System. Does they suits your needs ? I can update these graphics, or make other views, to suits your need if needed. Regards --Jean-Christophe BENOIST (talk) 09:37, 23 August 2011 (UTC)

Name of the article

I think we should swap the contents between the Flight dynamics (satellites) and Flight dynamics (spacecraft) articles, thus making the "satellites" article a re-direct to the "spacecraft" article. All the artificial satellites are spacecraft, and not vice-versa. Since this article deals with more general concept of the spacecraft flight dynamics (not just that of satellites), this should justify my proposition. cherkash (talk) 06:54, 13 December 2010 (UTC)

Well I agree that the current article name may not be the best one. But it appears that there is only one article, this one, Flight dynamics (satellites), and that the other, Flight dynamics (spacecraft) merely redirects to this one. So what name do you think best for an article on this topic? Are you saying that Flight dynamics (spacecraft) is the more general term and therefore, any satellite flight dynamics would be a subset of that? N2e (talk) 17:28, 13 December 2010 (UTC)

I thought my statement was clear (along with being precise). Apparently not. So specifically, I suggest putting the current contents of the "satellites" article into "spacecraft" article (by removing the re-direct there), and making this article (the "satellite" one) into a re-direct to the "spacecraft". cherkash (talk) 01:17, 21 December 2010 (UTC)

I agree although I do not think this a very important issue! Put the text under the heading "Flight dynamics (spacecraft)" and a redirect under "Flight dynamics (satellites)". There are a fair amount of interplanetary probes in the Solar System that one possibly could call "Artificial planets" but certainly not "Artificial satellites"! Stamcose (talk) 07:55, 15 December 2010 (UTC)

I don't understand your comment. How does "There are a fair amount of interplanetary probes in the Solar System that one possibly could call "Artificial planets" but certainly not "Artificial satellites"!" relate to the Name of this article? Cheers. N2e (talk) 20:40, 15 December 2010 (UTC)

• Support proposal by cherkash. Makes sense, as s/he points out, satellites are a subset of spacecraft -- so let's make the main dynamics article say "spacecraft." N2e (talk) 07:36, 21 December 2010 (UTC)

Does anyone know a good way to swap contents of two articles, without using the third (temporary) article name — and without simply copying/pasting (as this would lose page histories)? cherkash (talk) 00:11, 22 December 2010 (UTC)

DONE! User:Anthony Appleyard has helpfully completed the move, after what I see was a lot of prep work by User:Cherkash. Article is now entitled Flight dynamics (spacecraft). Thanks Anthony and Cherkash! N2e (talk) 13:23, 22 January 2011 (UTC)

Merge from proposal

There isn't much on the Attitude_control_system page that isn't covered here. This might possibly include a change of name from Flight_dynamics to "Spacecraft Attitude and Orbit Control" or some such. LunaCity (talk) 02:14, 14 November 2011 (UTC)

• SUPPORT the proposal to merge. Rationale: the Attitude control system article is little more than a bunch of wikilinks, with only one source, and that source refers to not only attitude control but also all the other aspects of spacecraft flight dynamics. Little is explained in that article, and what is, is not sourced. N2e (talk) 02:23, 14 November 2011 (UTC)

• STRONGLY DISAGREE The flight dynamics article suffers from a fundamental fallacy: it is written under the assumption that flight dynamics is exclusively concerned with a vehicle's attitude; it is not. As the name implies, flight dynamics is concerned with all aspects of a vehicle's flight trajectory, of which its attitude (spacial orientation) is only one factor. The Flight controller#Flight Dynamics Officer (FDO or FIDO) is responsible not just for a spacecraft's attitude, but for continually monitoring or predicting the vehicle's flight path, especially at such critical points (propulsive maneuvers) as launch to orbit, transfer from one orbit to another, and translunar (or interplanetary) injection. If the attitude control system article is inadequate, it should be marked as a stub or start-class, and improved, not merged. JustinTime55 (talk) 15:48, 14 November 2011 (UTC)

Okay, perhaps I don't really object so much to the merge proposal, as to the incorrect focus of this article. I tried to fix the lead to summarize what the proper definition should be. The article's major problem now is that it's way unbalanced toward attitude control, and "orbit control" isn't really the best description for the navigation and control (flight trajectory) aspect. Flight dynamics comes into play from the moment of liftoff, through termination of the flight (including re-entry if applicable). JustinTime55 (talk) 17:45, 14 November 2011 (UTC)

I renew my strenuous objection, and offer a counter-proposal. It looks like this article was orginally created as attitude control (spacecraft), then someone got the mistaken idea it was appropriate to move it to Flight dynamics, which is a totally separate (even if related) topic. JustinTime55 (talk) 21:44, 14 November 2011 (UTC)

Counter-proposal: Move-portions to Attitude control system

This is what I believe should really be done, so I have added the appropriate tags. JustinTime55 (talk) 21:44, 14 November 2011 (UTC)

I'm not accustomed to winning arguments so easily, but I'll take the default victory. This is now a fait accompli. I will now start filling this article with what flight dynamics is really about. JustinTime55 (talk) 17:22, 29 November 2011 (UTC)

Merge from spin-stabilized satellite and 3-axis stabilized spacecraft

Neither spin-stabilized satellite nor 3-axis stabilized spacecraft are more than stubs, despite having been created in 2006 and 2008, respectively. It's unclear if they even deserve their own articles - in my opinion, they would be much better as expanded subsections of this much more well-maintained and well-linked article. Kolbasz (talk) 11:31, 15 November 2011 (UTC)

STRONGLY DISAGREE - per the above. This "well-maintained and well-linked" article concerns Attitude control (spacecraft) rather than flight dynamics, so your merge would be more approriate there. JustinTime55 (talk) 15:09, 15 November 2011 (UTC)

CLARIFICATION: I don't disagree (or know if I agree), strongly or otherwise, about this merge suggestion's basic premise, that those articles should be merged with what is really Attitude control (spacecraft) (this discussion should be moved there); it's just inappropriate to merge them here into Flight dynamics. JustinTime55 (talk) 19:08, 30 November 2011 (UTC)

I'm with JT55, I support the basic idea of the merge, since those two articles are not deserving separate article status. However, we should probably merge into Attitude control (spacecraft) rather than the Flight dynamics (spacecraft) article. I will suggest that the proposer consider a new proposal, on Kolbasz's Talk page. N2e (talk) 03:01, 1 December 2011 (UTC)

Sure thing. As long as those almost-orphaned stubs end up somewhere. :) Kolbasz (talk) 21:20, 1 December 2011 (UTC)

Attitude Control (spacecraft) gets my vote on where they should be moved Ken Tholke 22:50, 1 January 2012 (UTC)

Dubious

The source cited says:

"Aircraft Flight Dynamics, MAE 331, is designed to introduce students to the performance, stability, and control [emphasis added] of aircraft ranging from micro-uninhabited air vehicles through general aviation, jet transport, and fighter aircraft to Mars planes and re-entry vehicles."

The course is about aircraft, but flight dynamics applies to both types of vehicles (which operate in slightly different venues), as Stengel indicates by including Mars craft in his course. There is a reason why the discipline is called Aerospace engineering.

This article originally, incorrectly defined the topic as being exclusively concerned with roll, pitch and yaw (Attitude control (spacecraft)), with absolutely no verification whatever. When I corrected the article, I wanted to provide verification and, absent explicit verification from NASA, I found what I considered to be the next best thing: a college course description on the subject. Why isn't a college professor's description a reliable source? JustinTime55 (talk) 19:04, 30 November 2011 (UTC)

No. That's not a wp:reliable source, it's not published, and that's a definition of that particular course, not necessarily a definition of this article's topic. It's also quite ambiguous as to whether it covers trajectory control or whether it's just attitude or not. I really don't care either way, but that's not a reference, and to the extent it is, it doesn't even define what we want.GliderMaven (talk) 20:26, 30 November 2011 (UTC)

Attitude control

This section needs a good English prose section intro, describing what attitude control is (and, maybe, is not) in non-mathematical English. It's fine to include a bunch of equations too, but Wikipedia is not to be only for tech geeks, so the equations better fit in a "details" or "equations" subsection further down. — Preceding unsigned comment added by N2e (talk • contribs) 21:30, 13 December 2011‎

I had touched on attitude control in the article's intro paragraph, and then sort of took it for granted (I don't think what attititude control means is "rocket science". :-). I will add an introductory paragraph to this section with a recap explaining pitch, roll and yaw orientation relative to a space-fixed axis, and the reasons why this is necessary.

• I think that's all that's required here; I don't know that a more detailed strtucture of subsections is warranted.
• I don't think this section is especially more technical than the rest of the article (which I honestly tried to make not too technical); it's a simple F=ma type linear equation: torque is applied, which leads to accelleration, which changes the rotational speed, which changes the rotation angle, just as linear thrust does to velocity and displacement.
• You used the wrong template; if you think it's too technical, the appropriate one is {{Technical|section}}. I only used Generalize because the article originally, artificially restricted Flight dynamics to the single topic of attitude control (which would be like restricting the Medicine page to oncology.) That's not the case here, which is only about attitude control. JustinTime55 (talk) 20:46, 21 December 2011 (UTC)

Hey JustinTime, I think that you made a lot of good edits to improve the article. Having said that, the overall article is rather full of equations that speak nothing to the typical reader of our encyclopedia. And my comment, which was limited to one section of the article for now, simply asks for adding some useful English prose to the attitude control section, which is what any section attempting to describe a major subtopic of spacecraft flight dynamics ought to include. So with your statement that you plan to write an intro to that section, that should definitely help incrementally improve the article.

On your comment about templates, I think you meant some other editor. Looks like the template in that section was already there before I added the comment about needing some English prose in the intro, and I added no template for that.

On the large number of equations in the article more generally, I have not asked that the equations be scaled back. Other editors might, but I have not. On the equations, I simply 1) want them sourced from a reliable source and to contain an inline citation—Wikipedia is not a place for equations that are worked up by us as editors, even if they are of the simple F=ma type. And 2), I hope to see the article improved to make sure that the typical Wikipedia reader can get an encyclopedic view into the topic even if they don't read maths. N2e (talk) 16:33, 22 December 2011 (UTC)

Magnetic torques and solar pressure?

The article reads,

For a spacecraft, these forces are of three types:propulsive force (usually provided by the vehicle's engine thrust); gravitational force exerted by the Earth or other celestial bodies; and aerodynamic lift and drag (when flying in the atmosphere of the Earth or other body, such as Mars or Venus)

Only three forces? Off the top of my head the article is missing at least two more: torques cause by the interaction of electrical currents in the spacecraft with the magnetic fields of the body being orbited (see Magnetorquer), as well as solar pressure which can induce torques in the spacecraft and is the whole principle behind solar sails. Is there a reason I'm missing that these aren't included? Otherwise I'll go through my university textbooks and source these additions to the article. R0uge (talk) 21:34, 22 March 2015 (UTC)

The three forces listed are those most commonly encountered by every spacecraft launched to date, and the forces are quite strong. The other two were probably overlooked because they are somewhat exotic; "Magnetorque" is a relatively new idea, and is used only for attitude control, not propulsion. And solar pressure (a linear force, not a torque) is quite weak, so far only having affected interplanetary probe trajectories and being used actively only once on MESSENGER. Other than this, solar sails are still theoretical. I would support adding an adjective like "generally" ("...these forces are generally of three types:"), then adding solar pressure (placed in context); and then mentioning magnetic force. We should follow the principle of WP:WEIGHT. JustinTime55 (talk) 13:48, 23 March 2015 (UTC)

As the article covers both translation and orientation of spacecraft, I think external forces that only induce torques should absolutely be mentioned. But I agree with weighting them less and throwing them under an 'other forces' section, I'll probably take a stab at it this week. (As a side note, solar pressure is indeed a linear force, but as the center of pressure of a spacecraft is rarely aligned with its center of mass, this usually induces a torque as well. But I digress.) R0uge (talk) 16:16, 23 March 2015 (UTC)

Article history

For reference purposes, here is a brief summary of the major history of this article, which began its life on a completely different topic:

• 2 March 2005: Created by an IP editor, under the title Attitude Dynamics & Control
• 10 November 2005: moved by Michael Hardy (talk · contribs) to MOS-conformant Attitude dynamics and control
• December 2008: tagged uncited
• 8 November 2010: moved by Guentherwagner (talk · contribs) to Flight dynamics (satellites)
• 21 January 2011: moved by Juansempere (talk · contribs) to Attitude control (spacecraft)
• 22 January 2011‎: moved by Cherkash (talk · contribs) to Flight dynamics (satellites)
• 22 January 2011: moved by Anthony Appleyard (talk · contribs) to Flight dynamics (spacecraft)
• 14 November 2011: yours truly discovers the page, woefully mis-scoped (lead sentence defines it as: Spacecraft flight dynamics is the science of space vehicle orientation and control in three dimensions.); begins first wave cleanup and expansion to include all aspects of spacecraft flight dynamics; runs out of steam 25 December.
• 26 June 2018: begin second wave of expansion / cleanup. JustinTime55 (talk) 17:48, 11 July 2018 (UTC)

I just did a bunch of cleanup to bring this closer to the norms of WP:MOSMATH. Michael Hardy (talk) 17:23, 12 July 2018 (UTC)

May 2020 changes

In my experience as an editor on WP, most edits to an article are incremental. I suppose that this has its positives and its negatives, as many small edits might tend to result in a loss of coherence over time.

However, I am wondering whether this extensive set of changes really represents an improvement in the article. Large changes such as this one tend to discourage discussion and diminish the benefits of an adversarial relationship between editors, which would otherwise help to maintain article quality.

Such extensive changes introduce the likelihood that there may be quite different visions of what a Wikipedia article on this topic should include, which would seem to merit a separate discussion. Fabrickator (talk) 21:33, 22 May 2020 (UTC)

I realize this comment is largely redundant with respect to my preceding comment, but over time, my perspective can change, so I thought I would take another look. Well, my perspective hasn't changed. I think most users would be far happier with the earlier version. Fabrickator (talk) 18:02, 10 June 2020 (UTC)

• Large changes ... diminish the benefits of an adversarial relationship between editors. There are no benefits of such an adversarial relationship which are recognized by the Wikipedia policies and guidelines. (Do a wiki search on the WP: namespace and see, you will get only one hit with a negative connotation.) Adversaries exist in politics and court rooms, not in a collegiate wiki where editors are expected to resolve their different opinions civilly and to achieve a neutral point of view.
• According to those policies, you need to WP:Comment on content, not on the contributor. All you have done is whined about the volume of changes I made, and haven't said a single thing about what you what you think is wrong with what I wrote. Large changes such as this one tend to discourage discussion; no, they don't. Blaming your inability to articulate your ideas on the volume of edits won't cut it.
• Our job as encyclopedia editors is to give the readers honest, accurate information about topics, not to keep them "happy".

I don't see how you can thoughtfully disagree with some of my edits. My first edit was in response to YTRK's request to disambiguate the phrase "vernal equinox"; I also filled in the blank sections "Propulsion" and "Gravitation". I also added some in-plane orbital maneuvers. You can't just revert changes willy-nilly without saying what's wrong with them. JustinTime55 (talk) 20:58, 10 June 2020 (UTC)

I just noticed you seem to be trying to sneak something new in; the "earlier version" you now link to dates from November 14, 2011, not just my May 2020 edits. This is totally out of order; that would revert many edits made by other editors, and take the article back to a totally erroneous definition of flight dynamics. Flight dynamics is not just attitude control (also note that article already exists, to which the 2011 version is redundant). I hold a bachelor of science degree in aerospace engineering, and thus am quite aware of the true definition of what flight dynamics is. I would be extremely interested to find out where you got your training in aerospace engineering, or where your quite different visions of what a Wikipedia article on this topic should include come from. Do you gaze into a crystal ball, or perhaps smoke peyote? JustinTime55 (talk) 15:00, 11 June 2020 (UTC)

Move discussion in progress

There is a move discussion in progress on Talk:Flight dynamics (fixed-wing aircraft) which affects this page. Please participate on that page and not in this talk page section. Thank you. —RMCD bot 09:45, 6 January 2023 (UTC)

Wrong formula?

In the "Propulsion" section, the formula that expresses the effective exhaust velocity of the rocket propellant:

v_e = g₀(I_sp-vac - A_ep_amb / ṁ)

has no dimensional homogeneity. Doing a dimensional check:

LT^-1 = LT^-2 (T - L² · ML^-1T^-2 / MT^-1)

that is:

T^-1L = T^-2L (T - T^-1L)

The terms inside the brackets are not homogeneous. TauZeta (talk) 20:32, 27 June 2024 (UTC)