Talk:SpaceX reusable launch system development program/Archive 1: Difference between revisions
Content deleted Content added
m Archiving 1 discussion(s) from Talk:SpaceX reusable launch system development program) (bot |
m Archiving 1 discussion(s) from Talk:SpaceX reusable launch system development program) (bot |
||
| (12 intermediate revisions by 2 users not shown) | |||
Line 33:
::{{u|N2e}}, I'm always willing to help with images, where possible. The issue is that SpaceX is a private company and their Grasshopper testing has been done in-house, without NASA photogs present :D I've scoured available resources for free images of Grasshopper, and what's on Commons is what's available. F9-R is even more problematic since it is such a new program. To be honest, it is highly unlikely that any free images of the new landing system will be available until it actually comes into use, and it is entirely possible images won't be available even then. This is just a note about the realities of the situation, and I'll continue checking to see if resources come available. I'll also try reaching out to SpaceX public affairs to see if they would be willing to release ''something'' under a free license (they've done so in the past, but only for early F1 material, iirc). <span style="white-space:nowrap; text-shadow:gray 5px 3px 1px;">— [[User:Huntster|Huntster]] <small>([[User talk:Huntster|t]] [[Special:Emailuser/Huntster|@]] [[Special:Contributions/Huntster|c]])</small></span> 06:47, 24 November 2013 (UTC)
Just a suggestion for images, there might be some scope to put a Falcon 9 image in either the background and/or testing sections. --'''''[[User:WDGraham|<
:{{done}} — I took your suggestion and added an in-flight photo of the [[Falcon 9 Flight 6]] launch vehicle, just minutes before it did the first-ever retro-deceleration and controlled-descent flight test. So while we don't have any Wiki-license friendly pics of the test we can use, we can show the same rocket on the same day shortly before that flight test was run.
Line 58:
::::However, the Mach numbers are still listed first, which is contrary to what the B-class reviewer ([[User:WDGraham]]) suggested: that the SI units (km/h) go first, ahead of the Mach no. and mph numbers. I have asked for some help on changing the order. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 23:50, 4 December 2013 (UTC)
:::::If we drop the mph unit entirely, then the desired result is possible from the conversion templates: {{convert/sandboxlua|6|Mach|105000|km/s|1|disp=flip|sp=us}}. Keeping the mph output does not seem to work with this approach, unless the template itself is edited to put the metric unit before the customary unit in the default output. (At least, I can't figure out how to get the template to spit out two non-default conversions from one input!) The conversion template is in the middle of a massive re-write, and {{tl|convert/q}} is one of the gateways to the new version. (However, on further research {{tl|convert/sandboxlua}} might be more appropriate.) [[Special:Contributions/130.216.218.47|130.216.218.47]] ([[User talk:130.216.218.47|talk]]) 05:57, 5 December 2013 (UTC)
::::::I'd suggest retaining mph since it is probably of use to American readers - my suggestion would be x.x km/s (Mach y, zzzzzz mph). If the template doesn't currently support it, using static text could be an option. --'''''[[User:WDGraham|<
:::::::Thanks for the explicit guidance, WDGraham. I've done a little experimenting with {{tl|convert/q}} in my sandbox, and will try to get back to this article soon to fix it in the way you suggest: probably with a combination of {{tl|convert/q}} template conversion plus a "static text" option to get the mph handled too, since the template doesn't seem able to handle both km/s and mph along with the Mach no. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 18:15, 5 December 2013 (UTC)
::::::::I've gone ahead and changed these Mach numbers to plain text. While I love the Convert template, it cannot handle all situations, and it's better to be completely plain text rather than a mix of template and plain text. <span style="white-space:nowrap; text-shadow:gray 5px 3px 1px;">— [[User:Huntster|Huntster]] <small>([[User talk:Huntster|t]] [[Special:Emailuser/Huntster|@]] [[Special:Contributions/Huntster|c]])</small></span> 20:32, 5 December 2013 (UTC)
Line 64:
::::::::::Strongly disagree. I don't believe 1.8 km/s would be nearly as meaningful to readers as 6546 km/h. While "per second" is the official SI form, "per hour" is for use by BIPM. <span style="white-space:nowrap; text-shadow:gray 5px 3px 1px;">— [[User:Huntster|Huntster]] <small>([[User talk:Huntster|t]] [[Special:Emailuser/Huntster|@]] [[Special:Contributions/Huntster|c]])</small></span> 01:51, 6 December 2013 (UTC)
:::::::::::Two thoughts. 1) On the km/s vs. km/h, it appears that you (Huntster) and WDGraham have different views. I don't believe that needs to be resolved here as part of the B-Class review, so I'll stay agnostic on that, for now, and perhaps we'll discuss it further later on. 2) on the Mach conversions, I found one more use of the convert|Mach template in the article that was rendering badly; so I have replaced it with the identical manual conversion numbers you put in the lede. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 01:17, 9 December 2013 (UTC)
:::{{od|::::::::}} km/h first is better than Mach first, and I think that is sufficient for the B-class review. Moving forward, would it be possible to adopt a similar compromise to the one reached at [[International Space Station]], with km/s first but kph given as an alternative unit, or would that just result in there being too many different conversions? --'''''[[User:WDGraham|<
::*{{done}}—for purposes of this B-Class review, I believe that now both issues related to Mach nos.—the non-US spellings and the conversions for Mach nos., leading with SI units—are complete. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 01:17, 9 December 2013 (UTC)
Line 77:
::* ('''under discussion''')—see Talk page section below working on a new article name.—02:57, 28 November 2013 (UTC)
::*{{Inconclusive}}—The "Article name" discussion, below, reached "no consensus." I don't believe the "little bit odd" article title should preclude the completion of the B-Class review, unless you want to go further and say that it is more than a "little bit odd" and is an "unacceptable" title for a B-Class article. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 01:45, 9 December 2013 (UTC)
--'''''[[User:WDGraham|<
:::*Although there is no consensus on where to move the page to, I'd say there is a strong consensus that ''it should be moved''. I'm going to provisionally mark this a B-class, on the condition that this issue is resolved by the end of the year. --'''''[[User:WDGraham|<
:::::Thanks for the review! And I agree with you on the move: all three who weighed in were in agreement that a move was necessary; they just didn't come together on one of the early suggestions. I'll try to get back here when I have more time to see if we can't get more editors involved for a second time around. A bit too busy to do it today.[[User:N2e|N2e]] ([[User talk:N2e|talk]]) 02:35, 10 December 2013 (UTC)
::::::Move has been completed, per the consensus developed below, so I believe that completes any concerns you had in your provisional pass at B-class review. Please let me know if you have any other concerns. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 16:46, 17 December 2013 (UTC)
Line 110:
:::But the end result is still a rocket that is reusable. If you include ground systems in this mix, even current tech is (mostly) reusable. The rocket is what matters here, in my mind. <span style="white-space:nowrap; text-shadow:gray 5px 3px 1px;">— [[User:Huntster|Huntster]] <small>([[User talk:Huntster|t]] [[Special:Emailuser/Huntster|@]] [[Special:Contributions/Huntster|c]])</small></span> 16:16, 25 November 2013 (UTC)
:Of the four options suggested above my preferences would be #1 or #2. The third option is too wordy and in any case the end result of the programme will hopefully be a reusable rocket rather than just technology which might lead to one. I'm not sure about the scope on #4 either; this article will cover the development of the rocket but I would expect a separate article will be created when it actually starts flying. --'''''[[User:WDGraham|<
::Thinking about it a bit more, I much prefer #2, principally because it avoids the impression of the development of a single rocket. This development program is building a set of technologies that will be used as new piece parts of the booster of two existing rockets ([[Falcon 9]] and [[Falcon Heavy]]), and will be worked in in later years into one or more rocket second stages. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 04:23, 26 November 2013 (UTC)
Line 153:
::Maybe this is what you were talking about Huntster, but mach is a relative term. Mach 1 at sea level is not the same as mach 1 at 10km above sea level. So how exactly do we convert those units into SI when we don't have at the very least altitudes to work with?
::On the other points N2e brought up, I'll agree with both suggestions. Rounding to two significant figures would be fine, and km/s is probably better, even though it's less likely to be understood by a casual non-technical reader. If they want they can click on a wikilink and see what it means. — [[User:Gopher65|Gopher65]]<sub><small>[[User_talk:Gopher65|<
:::This is exactly what I was referring to Gopher...we'd need a source which gives the altitudes of first stage sep to properly convert the Mach figures. The Mach 10 sep figures for existing F9 rockets shouldn't be difficult to find, but I don't know that the Mach 6 altitudes are going to be available. If we can't find these altitude figures, it will be entirely inappropriate to provide conversions, as they will simply be wrong. I still do feel catering to the casual reader is important, though; I think most will know that "km/s" is kilometers per second, but I'm not sure that it will be nearly as meaningful as kilometers per hour...simply clicking a link isn't going to increase innate understanding of the figures. <span style="white-space:nowrap; text-shadow:gray 5px 3px 1px;">— [[User:Huntster|Huntster]] <small>([[User talk:Huntster|t]] [[Special:Emailuser/Huntster|@]] [[Special:Contributions/Huntster|c]])</small></span> 01:25, 30 December 2013 (UTC)
::::Huntster, good point about the altitude. I'll offer two comments. 1) however much we need the altitude as the article is today, with four significant digits in the conversion, we need worry about it a ''bit'' less when we are going only for two-significant digits in the converted numbers. 2) an easy way out, which solves the significant digit issue AND the less-than-certain altitude problem, is to use either an "approximately x.y km/s" or perhaps could provide a range of speeds that would cover the estimated altitude range. Either way, I don't think we should go with leaving only a Mach no. in an encyclopedia article for a general readership. Cheers. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 01:55, 30 December 2013 (UTC)
:::As I understand it, you're proposing that we switch to only mach numbers, because you don't have the altitude at which those mach values are correct. If you don't know the altitude then what use are the mach numbers anyway? It's just an arbitrary figure. --'''''[[User:WDGraham|<
::::It's an interesting point. The mach numbers really are fairly meaningless here ''except'' that it gives readers an idea that there is a significant speed difference for first stage sep between F9 and F9R. <span style="white-space:nowrap; text-shadow:gray 5px 3px 1px;">— [[User:Huntster|Huntster]] <small>([[User talk:Huntster|t]] [[Special:Emailuser/Huntster|@]] [[Special:Contributions/Huntster|c]])</small></span> 12:07, 30 December 2013 (UTC)
Line 328:
::I agree that the wording is poor and should be changed (it isn't almost impossible, it's "merely" difficult. Heh. Merely.). However, that bit about the "3% of the mass of the rocket" is quite true. In most 2 stage rockets, like the Falcon 9, it's more like a little less than 2%. Some particularly well designed, highly efficient, low safety margin, 3 stage rockets can hit 4%. It doesn't go much higher than that. Chemical fuel just isn't energetic enough for better numbers.
::The issue is that adding reuseability to a rocket is estimated to reduce payload to orbit by a bit more than 2 percentage points. For most 2 stage rockets that would mean the extra mass would be enough to stop them from obtaining orbit (less than 2% - more than 2% = nothing making it to orbit). Or, as Musk put it, they have a "negative payload to orbit". The 3% given in the article is just an averaging of the industry standard 2-4% figure. It should be replaced by "2 to 4 percent" IMO. SSTO vehicles face similar problems, by the way. The added weight reduces their payload to orbit to negative numbers. — [[User:Gopher65|Gopher65]]<sub><small>[[User_talk:Gopher65|<
:::Not all of it is true. It's true that payload fractions are only a few percentage points, but that can be overcome by using multiple stages. Whether that is economical is another question, but there is no doubt that it is physically possible. Whether (reusable) single stage to orbit is possible is not certain. Some believe it is, others are skeptical. Two stage to orbit is generally believed to be possible, and three stage to orbit should be no problem. [[User:Mmeijeri|Martijn Meijering]] ([[User talk:Mmeijeri|talk]]) 08:23, 2 August 2014 (UTC)
Line 459:
::Yes, in the main. I just added some prose to the article based on a source I found. One detail relative to what you said: I also listened to a recording of the 15-20 minute phone call teleconference that the press had with Elon Musk after the flight, and I don't believe anything was said about "dismantling" the F9 Flight 20 vehicle. I suspect what is more likely is that, after evaluating the overall structure in fine detail, some pieces from key areas of stress may be cut out or otherwise removed for [[destructive testing]]. I don't think that will happen to such an extent that the vehicle is hugely disfigured; Musk seems to want the rocket to stand as a memorial or museum piece, since he thinks they will have quite a few stages to refly in the near future (not all future flights, but thinks likely to have stages back from most of them). Cheers. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 05:09, 24 December 2015 (UTC)
== 22 December 2015 post-landing news conference with Elon Musk ==
Here is a recording (link [http://forum.nasaspaceflight.com/index.php?topic=38148.msg1463773#msg1463773 here]) of the post-launch and post-landing teleconference with the press that Elon Musk gave, only an hour or two after the landing. The audio has quite a bit of wind noise on the microphone; but you can hear everything the reporters heard. That YouTube audio was posted yesterday, 23 Dec 2015.
Today, someone has helpfully posted a full transcript of the recording. (link [http://shitelonsays.com/transcript/postlanding-teleconference-with-elon-musk-2015-12-22 here]). If you use any of this as a primary source to details about the launch, flight, landing, future plans, etc., you should recognize this is a [[WP:PRIMARYSOURCE|primary source]], and while okay to use for [[WP:V|verifiability]] purposes in some cases, is not considered as good a source for Wikipedia as a secondary source, something written on by a reliable source (like a newspaper, or one of the space media journalists). Cheers. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 10:32, 24 December 2015 (UTC)
== Disagreement between Intro and History ==
The first paragraph of the Introduction states that "the project's long-term objectives include returning a launch vehicle first stage to the launch site in minutes and to return a second stage to the launch pad" - this is at odds with the last paragraph of the History section which states that "by late 2014, SpaceX suspended or abandoned the plan to recover and reuse the Falcon 9 second stage". <small><span class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:JHarvey418|JHarvey418]] ([[User talk:JHarvey418|talk]] • [[Special:Contributions/JHarvey418|contribs]]) 18:19, 14 August 2015 (UTC)</span></small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->
:Good observation. We should probably clean up the text. But I think the contradiction dissapears when one recalls that this SpaceX technology development program is not specific to just the Falcon 9 launch vehicle. The company has decided ''not'' to pursue Falcon 9 second-stage reuse; they absolutely have a long-term goal of second-stage reuse also as a part of this tech dev program. It would appear, based on company statements to date, that the second-stage reuse will get additional development effort when the [[MCT launch vehicle]] development get's underway with more than the skeleton crew of current design resources. Cheers. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 19:20, 14 August 2015 (UTC)
::Since this discussion in August, I've added some prose to endeavor to explicate the distinction: aiming for both stages long term, but the near-term Falcon 9 focus is only on the first stage. See what you think. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 05:38, 25 December 2015 (UTC)
== Maintenance + unmanned ==
High maintenance costs ruined the economics of the reusable Space Shuttle. But that was presumably at least partly due to the Shuttle having to be extra safe to carry people, so that Falcon 9 may perhaps avoid similar problems if its payloads stay unmanned. Are there no reliable sources discussing these matters, or if there are, shouldn't they appear in the article? (The Space Shuttle's problems meant that I assumed Falcon 9 was just hype until I worked out the above arguments, but if those arguments are correct I shouldn't have had to try to work them out for myself, and neither should our other readers).[[User:Tlhslobus|Tlhslobus]] ([[User talk:Tlhslobus|talk]]) 13:27, 23 December 2015 (UTC)
: As I understand it, many parts of the Space Shuttle had to be stripped down and rebuilt with every flight. I believe SpaceX's aim is to be able to just refuel and relaunch, in the same way as an aircraft can be refueled and relaunched. Presumably they intend to use telemetry and non-destructive inspection techniques to avoid the need for a full maintenance inspection every time. SpaceX certainly intend to make the Falcon man-rated. -- [[User:The Anome|The Anome]] ([[User talk:The Anome|talk]]) 13:40, 23 December 2015 (UTC)
::Thanks. But the article currently has no mention at all of any of that in the Economic Issues and Technical Feasibility sections, which is where sceptical-but-open-to-persuasion readers like me are going to head, and not much of it elsewhere either, in the sense that it's perhaps implicit in Elon Musk's stated wishes, but an owner's wish list is not a very informative discussion of an issue. Indeed apart from wishful talk about hoping to colonize Mars (which we've been hearing for 50 years, despite the discovery of serious problems with solar flares, and cosmic rays, and the lack of any serious '[[Artificial gravity]]' research programme on any of the various space stations), the article gives the impression that the serious plans are currently only for reusable rocket stages 1 and 2, which for a manned rocket is the equivalent of re-using the rockets but throwing away the manned bits, at least leaving the impression that any manned flight will be much less reusable than the Space Shuttle. [[User:Tlhslobus|Tlhslobus]] ([[User talk:Tlhslobus|talk]]) 14:19, 23 December 2015 (UTC)
:::If you're talking about Earth-bound missions, I believe that SpaceX intends to make all three components reusable: the first stage and second stage boosters, and the Dragon capsule, all landing vertically on their own rocket thrust. In the case of the Dragon, the landing rockets are also planned to serve as the attitude thrusters and launch escape mechanism. I can't find a reference for this at the moment, but they released a video last year (with a backing track by Muse, IIRC) showing an animation of how the whole process is intended to work. We really need to have this covered in more detail in the article. Mars I don't know about. -- [[User:The Anome|The Anome]] ([[User talk:The Anome|talk]]) 14:36, 23 December 2015 (UTC)
::::::You are correct, in the long term, but not for the nearer term, with the Falcon 9/Falcon Heavy. Both are addressed in the article prose, but perhaps could be made more clear.
::::::#In the lede it says "The project's '''long-term''' objectives include returning a launch vehicle first stage to the launch site in minutes and to return a second stage to the launch pad following orbital realignment with the launch site and atmospheric reentry in up to 24 hours. SpaceX '''long term''' goal is that both stages of their orbital launch vehicle will be designed to allow reuse a few hours after return.[1]". (emphasis added)
::::::#In the History section, it says: "By late 2014, SpaceX suspended or abandoned the plan to recover and reuse the Falcon 9 second stage;[33] the additional mass of the required heat shield, landing gear, and low-powered landing engines would incur too great a performance penalty."
::::::So, using all extant sources we have, SpaceX is still aiming for this, but in their [[MCT launch vehicle]] and in the [[Mars Colonial Transporter]]; ''not'' with the [[Falcon 9]] nor [[Falcon Heavy]]. (however, with the new USAF contract to SpaceX earlier this month for SpaceX to develop an "upper stage" Raptor-like methane-fueled full-flow-staged-combustion '''prototype''' engine for the F9 and FH (see the article lede of [[Raptor (rocket engine)]] for a source), there is some speculation that a newer/newish second stage design for F9/FH ''might'' be able to be reusable, like Musk originally wanted, rather than like SpaceX decided to drop development resources from in late 2014, as shown in the quotation above. SpaceX, however, has neither confirmed nor denied any interest in even making a stage that would ever fly with the new USAF-1/3-paid-for prototype engine, nor publically said anything about making such a hypothetical stage reusable, ''contra'' the earlier late 2014 plans. YMMV.) Cheers. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 23:36, 19 January 2016 (UTC)
::::Thanks for the great info, {{U|The Anome}}. I wonder can that video be used as an acceptable RS, if it can be found? Also, do you by any chance know whether they say anything anywhere about returning to the Moon (or is it all just about Mars, with its far greater and possibly insuperable problems for the human body)?
:::::Think I have seen a Elon Musk interview where on being asked this question he likened it to if you build an aircraft capable of crossing the Atlantic then are there going to be other people flying across the English Channel? That of course doesn't indicate that SpaceX have moon plans and may tend to indicate either they don't or they don't want to disclose any plans they have. Impression was he thinks it is inconceivable we would do Mars and not also have someone else doing something on the moon. [[User:C-randles|crandles]] ([[User talk:C-randles|talk]]) 17:12, 23 December 2015 (UTC)
::::::He used boats rather than planes. See [https://www.youtube.com/watch?v=y13jbl7ASxY&feature=youtu.be&t=23m20s] [[User:C-randles|crandles]] ([[User talk:C-randles|talk]]) 23:22, 23 December 2015 (UTC)
== First stage velocity at separation ==
It is probably time to revisit the article info on separation speeds before booster flyback. New, specific, info is available on the first two actual flights of the [[Falcon 9 full thrust]] version of the rocket is now available: [[Falcon 9 Flight 20]] in Dec 2015 and [[Falcon 9 Flight 22]], slated for launch later today. This source (<!-- <ref name=reuters20160223> -->
{{cite news |last=Klotz |first=Irene |url=http://www.reuters.com/article/us-space-spacex-ses-idUSKCN0VW2O7 |title=Satellite operator SES says interested in used SpaceX rocket |work=Reuters |date=2016-02-23 |accessdate=2016-02-24 }}<!-- </ref> -->) provides clear info on the Falcon 9 part of the question:
<blockquote>the rocket launching this week will be flying almost twice as fast as the one used in December - between 4,971- to 5,592 mph ( 8,000- to 9,000 kph), compared to 3,107 mph (5,000 kph) - by the time it separates from the second-stage motor, SpaceX said. </blockquote>
FWIW, the info on these velocities that is currently in the first paragraph of this article, is based on orginal forward-looking design information from several years ago in 2012 (and there was lengthy Talk page discussion getting to that...):
<blockquote> If the technology is used on a reusable Falcon 9 rocket, the first-stage separation would occur at a velocity of approximately 2.0 km/s (6,500 km/h; 4,100 mph; Mach 6) rather than the 3.4 km/s (11,000 km/h; 7,000 mph; Mach 10) for an expendable Falcon 9, to provide the residual fuel necessary for the deceleration and turnaround maneuver and the controlled descent and landing.</blockquote>
So the article will definitely need an update, and I don't have time to do it just now. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 12:57, 24 February 2016 (UTC)
== Flight 22 landing: Significance of extra push - consequently phrasing looks wrong ==
{{ping|N2e}}
There was an agreement that an extra push would be given to reduce time to reach final orbit. This came from '''second''' stage being run until depletion of fuel rather than shutting down when a target orbit was reached. This has very little, if any, effect on amount of fuel left in '''first''' stage. I don't mind this piece of information being given - Not quite sure where I would move it to. Seems well covered in [[Falcon_9_Flight_22]] and not sure it needs to be here as well. However, I do object to phrasing that indicates that because of the extra push there is little fuel left to land the first stage. Far, far, more important is that the payload was heavy for being lifted to GTO. Unless you have or there is a reference indicating such importance, such a level of importance should not be implied by the article. So the phrasing should reflect this. If other editors want to insist on including mention of the extra push fine but for accuracy don't phrase to indicate this is primary reason for little fuel being left to land first stage. Can we please change the phrasing or remove it? [[User:C-randles|crandles]] ([[User talk:C-randles|talk]]) 14:12, 9 April 2016 (UTC)
:I get your two points. I don't have time to relook a the sources just now, but in the long news conference by the SES executive Halliwell I recall him mentioning the extra push, and impact on the probability that SpaceX successfully landing the first stage would go down. It seemed to me, as I heard that and other sources, that given SpaceX's loss of flight 19, and subsequent 6 or so month delay to the return-to-flight, it pushed SES back a bunch, and thus reduced SES near-term revenue statements (SES were going public on that in securities regulation announcements), and since SES is a really good (though not exclusive) SpaceX customer, SpaceX decided to "take one for the customer" and burn harder/longer, and reduce landing probability of the experimental controlled-descent first stage. No problem; all good business. But the push or extra burn or whatever was mentioned by Halliwell, and picked up by space media who covered that. So I think the extra push should not be left out of the article. On your second point, I have not seen sources that clarify how much of the extra push was first stage vs. second stage. Given the extra push was talked about, and sourced, it is not at all clear that just because the second stage did a "burn to (safe) depletion" rather than a "burn to target orbit", then that would mean the first stage didn't give some extra push also, and thus use up some of the propellant that would have been part of its return and landing prop margin; SpaceX clearly decided to do a special 3-engine landing burn on flight 22, never before even tested, in order to have a (small probability) shot at bringing the thing in and landing it. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 18:55, 9 April 2016 (UTC)
::I fully agree with [[User:C-randles|crandles]] on {{diff||714371128||this edit}} which improves the reader's understanding that mass and speed are the key factors in setting practical limits to booster recovery. Here we had a rocket which couldn't reduce its re-entry velocity as much as would be feasible on a LEO Dragon launch, for example. That being said, I would assume that the negotiated supersynchronous trajectory had an impact on the first stage as well as the second stage, taking both of them to their limits? However we are surely going down the sweet and sour path of [[WP:OR]]... This case was undoubtedly a great way to push the envelope on what these Falcons can withstand! — [[User:JFG|JFG]] <sup>[[User talk:JFG|talk]]</sup> 07:26, 10 April 2016 (UTC)
:::Looking again at the ref http://spaceflightnow.com/2016/02/24/falcon-9-rocket-to-give-ses-9-telecom-satellite-an-extra-boost/] "Halliwell said SES’s contract with SpaceX called for the rocket to deploy SES 9 into a “sub-synchronous” transfer orbit with an apogee around 16,155 miles (26,000 kilometers) in altitude. ... The change in the Falcon 9’s launch profile will put SES 9 into an initial orbit with an apogee approximately 24,419 miles (39,300 kilometers) above Earth." 26000km to 39300km is quite a difference that doesn't seem likely to come from just a couple of extra seconds burn from the second stage. This makes it seem to have a more significant effect than I was thinking when reading the change was just a slightly longer burn on the second stage. Would still suggest payload weight "heavier than the Falcon 9 rocket’s advertised lift capacity to geosynchronous transfer orbit" is likely a major effect but without reference we shouldn't indicate which is more important. Can we find a wording that suggests both are factors without indicating one is more important than the other? Perhaps I will have a go at adding a little more. Hope bit added serves. [[User:C-randles|crandles]] ([[User talk:C-randles|talk]]) 11:05, 10 April 2016 (UTC)
::::Sure, give it a go. That was why I suggested we beat it around on the Talk page for a bit. Just was a shame to lose that aspect of the extra energy added for movement of the trajectory to a higher energy orbit, and one that was beyond what the contract called for. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 02:23, 12 April 2016 (UTC)
== Source ==
This video of Musk news conference following the second successful landing of a booster (first one was Dec 2015, on land), and the first one on a droneship, explains a bit about the test philosophy, and why do it on an active orbital mission rather than as most government-funded missions to date where the test flight itself would be a single planned dedicated mission. [https://www.youtube.com/watch?v=VNygOavo2mYElon Musk Discusses CRS-8 Successes with Media], 8 April 2016, at 19:20-21:50. Would be a good source to potentially improve the article. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 02:44, 16 April 2016 (UTC)
== Fairing ==
SpaceX is working on fairing reusability. I may add a mention of that. --[[User:Pmsyyz|Pmsyyz]] ([[User talk:Pmsyyz|talk]]) 16:23, 6 March 2017 (UTC)
:And they achieved a recovery on the 30 March 2017 launch. It is now mentioned in the article, and sourced. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 04:55, 1 April 2017 (UTC)
== Deeper and more analytical secondary sources ==
Now that it's been over a day since the successful launch and flight of a "flight-proven" booster stage, the deeper and more serious pieces of space media journalism are being posted.
* this one has a good bit of sourced info on costs, flight rates, etc. [https://www.spaceintelreport.com/spacexs-reusability-effort-faces-one-more-big-challenge https://www.spaceintelreport.com/spacexs-reusability-effort-faces-one-more-big-challenge].
* [https://www.nasaspaceflight.com/2017/03/spacex-historic-falcon-9-re-flight-ses-10/ https://www.nasaspaceflight.com/2017/03/spacex-historic-falcon-9-re-flight-ses-10/] [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 05:48, 1 April 2017 (UTC)
== Rename article? ==
Given that the system has now been used for a real mission, is it perhaps time to rename this article to "[[SpaceX reusable launch system]]"? Certainly, development is continuing, as SpaceX works to reduce costs and turnaround times, and to make even more parts of the system resusable, but the system is now no longer purely in an R&D phase; it exists, and is operational. -- [[User:The Anome|The Anome]] ([[User talk:The Anome|talk]]) 09:08, 2 April 2017 (UTC)
:SpaceX has indeed reached a key milestone in their drive towards full reusability, but that's not a reason to rename this article, which documents their R&D process. The resulting operational system is described at [[Falcon 9 Full Thrust]], [[Falcon 9 Block 5]], [[Autonomous Spaceport Drone Ship]], [[Landing Zone 1]], [[SpaceX]] and probably other pages. Meanwhile R&D activities continue: half a fairing was recovered, there is work to enable fast "refuel and relaunch" turnaround, and just this weekend Musk mused about trying to enable recovery of the second stage. Plus some ITS work would come here too. All in all, more reasons to keep the page as a description of reusability R&D efforts. — [[User:JFG|JFG]] <sup>[[User talk:JFG|talk]]</sup> 02:25, 3 April 2017 (UTC)
::Agree with [[User:JFG|JFG]]. This article is an encyclopedic description of the overall development program to achieve this significant advancement in human technology. Took years, broad vision, and the overall technology advancement here is much larger than any particular reusable launch system. This is about a set of ''multiple'' technologies--in engines; materials science; guidance, navigation and control; hypersonic ==> subsonic atmospheric flight controls; business; private incentives; competition; interdisciplanary systems development; etc.--being used on ''multiple'' reusable launch systems: Falcon 9, Falcon Heavy and the Interplanetary Transport System. Not even all of the technologies used/tried/engineered/iterated and experimented with even made it to the final system in use in F9 today, let alone what will be developed for the next-generation interplanetary launch vehicles and spacecraft.
:: Having said that, there may one day be room (or need) for an article on some particular current reusable launch system, that would not have all the encyclopedic breadth of this article. That's fine, when the need arises. But this article's scope would be misrepresented by re-titling it as proposed. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 19:53, 20 April 2017 (UTC)
== External links modified ==
Hello fellow Wikipedians,
I have just modified 3 external links on [[SpaceX reusable launch system development program]]. Please take a moment to review [https://en.wikipedia.org/w/index.php?diff=prev&oldid=780011123 my edit]. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit [[User:Cyberpower678/FaQs#InternetArchiveBot|this simple FaQ]] for additional information. I made the following changes:
*Added archive https://web.archive.org/web/20131207085028/http://www.faa.gov/about/office_org/headquarters_offices/ast/environmental/nepa_docs/review/documents_progress/spacex_texas_launch_site_environmental_impact_statement/media/SpaceX_Texas_Launch_Site_Draft_EIS_V1.pdf to http://1.usa.gov/YtxBzo
*Added archive https://web.archive.org/web/20140322013556/http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 to http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3
*Added archive https://web.archive.org/web/20140322013556/http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 to http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
{{sourcecheck|checked=false|needhelp=}}
Cheers.—[[User:InternetArchiveBot|'''<span style="color:darkgrey;font-family:monospace">InternetArchiveBot</span>''']] <span style="color:green;font-family:Rockwell">([[User talk:InternetArchiveBot|Report bug]])</span> 11:38, 12 May 2017 (UTC)
== "Starship hopper"? ==
There is a section heading in the article now entitled "Starship hopper." Do we have a source where SpaceX is calling the first test article "Starship hopper"? If not, is is a widely used name such that it might be sort of a "common name" for it?
I've seen the name used somewhere... but I've also seen media calling it the "BFR dev ship", a "hopper", the "BFH", the "BFWT" (water tank, 'cause that's what it was thought to be as build began in Dec 2018 in what later became the Boca Chica Spaceshipyard), etc. Descriptively, and not trying to use any one particular cute name, it is simply just the ''Starship test flight rocket.'' . In other words, not sure Wikipedia should be using something that isn't a common name, nor a name SpaceX is calling it. Cheers. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 01:39, 29 January 2019 (UTC)
== Second stage as spaceship ==
The "Second-stage reuse" section of the article currently states an, "integrated second-stage-with-spaceship design [...] has not been commonly used in previous launch vehicles." But see [[RM-81 Agena]]. The final launch was in 1987; 365 were flown. Does that flight history somehow fail to qualify Agena as having been "commonly used?" ([[User:Sdsds|sdsds]] - ''[[User talk:Sdsds|talk]]'') 06:15, 22 May 2018 (UTC)
:Just saw this question [[User:Sdsds|sdsds]]. Is a good one. I had time only to skim that Wikipedia article prose, but not go after the sources. Do you think there is a good source anywhere that does a solid job explicating just how the Agena might be thought to have been an "integrated second-stage-with-spaceship design"? Otherwise, it seems a bit like Agena, and maybe even a few of the Chinese second stages being used today, are more "integrated second-stage-with-attached satellite" designs. But even that might be worth mentioning to improve this article if we could find sources that are descriptive of some sort of integrated-second-stage designs in contrast to the BFR design integrated reusable spaceship designs. Cheers. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 14:20, 8 November 2018 (UTC)
::Ah, thanks [[User:N2e|N2e]] your thinking on this is good. Musk (the cited source) pretty clearly knows "spaceship" can refer to both a human-carrying and a satellite- or probe-carrying vehicle, but he might mean us in this context to be thinking of human-carrying vehicles where (to my knowledge) nothing quite like what's envisioned for BFS was ever "commonly used." (Or ever used at all?)
::I'm sure there are sources we could cite describing Agena (and the others you mention) as being integrated second-stage and payload vehicles but in the context of Musk's assertion, mentioning that what he said might be misconstrued would probably be out of place! ([[User:Sdsds|sdsds]] - ''[[User talk:Sdsds|talk]]'') 02:20, 31 August 2019 (UTC)
== Recent edits ==
I reverted the recent [[WP:BOLD|Bold]] and [[WP:AGF|good faith]] edits that added a detailed numeric list of all the many years of test flights to this [[WP:GA]] good article. Let's [[WP:BRD|discuss]] it on first and see if ther is a consensus for this change.
This article describes a long-term multi-year program of technology development for many different launch and spacecraft systems at SpaceX, and describes the development of fundamental rocket technology that Musk has said SpaceX will have failed if they don't eventually get there: fully and rapidly reusable rockets. I don't believe it will be helpful to have yet another article with a detailed count of every test flight and success/failure/who knows. Rather, this article can reference those other articles that maintain detailed counts by the particular vehicle. [[User:N2e|N2e]] ([[User talk:N2e|talk]]) 12:18, 30 August 2019 (UTC)
:You also reverted several other good changes. You also added back information that is obviously outdated. Could you please only revert the part you object to and not just blindly revert everything because you object to half a sentence? There was no "detailed numeric list", there was a first and last flight. We also list the first and last flight for a couple of other vehicles in the article, I don't see what would be different for Starhopper. --[[User:Mfb|mfb]] ([[User talk:Mfb|talk]]) 03:12, 31 August 2019 (UTC)
| |||