SpaceX reusable rockets

Ok, vsakemu bebcu je bilo jasno, da bodo uporabili padala za fairinge.

Medtem, ko si ti govoril o uporabi padal za rakete. Preberi si svoje poste.

Če ne vidiš razlike med raketo in fairingom, potem ...

Medtem, ko SpaceX pripelje 20+ raket nazaj z motorji, nekatere od teh raket uporabi celo po dvakrat in jih obakrat uspesno pripelje na tla z motorji (enkrat celo dve raketi samo z nekaj sekundnim zamikom), vostok se kar naprej trabunja o padalih. In hkrati pozabi se, da padala niso nikoli bila sporna za recovery kaksnih drugih zadev. Ze za Dragon kapsulo smo nekateri rekli, da so padala bolj preizkusena kot kak drug nacin. Kapsula, fairingi? Seveda, zakaj pa ne? Ene desetkrat tezja raketa, visine povprecne ljubljanske stolpnice, ki mora pristati z max 5m/s in brez lateralne hitrosi? Ne.

Invictus je 22. feb 2018 ob 19:04 izjavil:

Je pa zadeva že delovala, samo ni certificirana.

Ja, saj vemo. Sicer celotnega testa in pristanka niso nikoli izvedli, samo teste na tleh, ce se prav spomnim.

Invictus je 22. feb 2018 ob 19:04 izjavil:

Upam, da danes vostokova žena dobi dvojno dozo zaradi padal .

Katera zena? Leva ali desna? :>

Levanka Rukić

Case: Lost.

Naslednja misija bo zelo zanimiva :D kar se tiče pristanka.

Hispasat 30W-6
GTO
6092 kg

Gre za zgornjo limito. Govori se o suicide burnu 1-3-3.

6761kg: Intelsat 35e, expendable.
6092kg: Hispasat 30W6, attempting recovery.
6086kg: Inmarsat 5-F4, expendable.
~5500kg: Echostar 23, expendable.
5330kg: SES-9, punched hole in barge.
5281kg: SES-10, recovered (heaviest success)
~5200kg: SES-11, recovered.

Torej je zdaj edini expendable del F9 druga stopnja. Pri devetki bo sicer tako ostalo, z BFR pa bo tudi tista reusable. Odlicno.

Ali kdo ve, boosterji ki letijo dvakrat, ali jih razstavijo in ponucajo motorje se veckrat?

vostok_1 je 24. feb 2018 ob 00:18 izjavil:

Logično. A ste presenečeni?
To je BW & Co. prerokoval že 15 let nazaj, da je smiselno naredit. Vključno z self-steering padali, ki kljubujejo vetru.

Ne nismo. Če bi imeli fairingi vgrajene motorje (bog ve zaradi kakih razlogov), bi uporabili le te...

Samo padala ne morejo kljubovati vetru. Samo prilagodijo se mu...

Vprašanje je samo natančnost. In cena pobiranja. Saj verjamem da se da kar precej natančno izračunati mesto pristanka. Če zapiha malo drugačen veter, je pa vprašanje kaj in kako...

Vprašaj kakega jadralnega padalca kako lahko kljubuje vetru...

Seveda je pa tudi vprašanje, kolikšno vertikalno hitrost prenesejo fairingi preden se poškodujejo. Če je le ta precej velika, je padalo lahko manjše in ima veter nanj manj vpliva.

https://www.space.com/39784-spacex-catc...

Seveda je to dokaz, da padala le niso tako natančna kot trdi vostok_1 . Booster bi to precej slabše preživel...

Seveda je pa super uspeh, da so to sploh uspeli dobiti nazaj. Še en pljunek v faco NASA šefom. Konkreten mastič...

vostok_1 je 24. feb 2018 ob 10:46 izjavil:

Nikoli trdil, da so natančna.

Zgolj BW bi rad 20 etažne stolpnice lovil na meter natančno.

Saj Musk tudi.

Zato boosterji pristajajo z motorji .

vostok_1 je 24. feb 2018 ob 10:46 izjavil:

Nikoli trdil, da so natančna.

Zgolj BW bi rad 20 etažne stolpnice lovil na meter natančno.

1 meter je prevec, plus minus 3m v 95% verjetnostnem intervalu bo zadost, vendar pa zal tvoja padala tega ne zmorejo

7982884e je 24. feb 2018 ob 11:22 izjavil:

vostok_1 je 24. feb 2018 ob 10:46 izjavil:

Nikoli trdil, da so natančna.

Zgolj BW bi rad 20 etažne stolpnice lovil na meter natančno.

1 meter je prevec, plus minus 3m v 95% verjetnostnem intervalu bo zadost, vendar pa zal tvoja padala tega ne zmorejo

Nikoli ciljal na tako natančnost. To sem že v štartu lepo povedal.
Ampak to nič ne ustavlja BWja, da briše in zaklepa.

Truga je 24. feb 2018 ob 12:08 izjavil:

Predvsem so padala pretezka.

Da. Fi 300m padala morda res. Ampak to je zgolj BWjev strawman, da lahko briše in zaklepa nasprotna mnenja.

Izredno veliko. Teh 300m give or take.

vostok_1 je 24. feb 2018 ob 13:40 izjavil:

Izredno veliko. Teh 300m give or take.

vostok, a nisi ti izgubil stave, po kateri si se odpovedal govorjenju o padalih in Falcon 9 v isti povedi?

---> noone gives a shit about your chutes <---

Padalo lahko varno odpres sele takrat, ko se premikas pocasneje od zvoka in od takrat naprej bi bilo zaviranje zavoljo varcevanja goriva predvsem vnasanje se ene komponente, ki bi celotno zadevo dodatno zakomplicirala in verjetno tudi podrazila. Pri Falcon 9 so ze eksperimentirali s padali, pa so ugotovili, da ta stvar ne bo sla skozi. Ce se potrudis lahko najdes fotke Falcon 9 interstage-a s padali. :>

Landing burna je zdaj za cca 35 sekund. To je za kaksne tri tone in pol goriva. Ce jim uspe pristanek s tremi motorji bodo te tri tone in pol verjetno razpolovili.

Seriously, padala so brez veze.

vostok_1 je 28. jan 2018 ob 11:46 izjavil:

Jo je kdo že zasledil na nebu?

Jutri ob pol sedmih zjutraj naj bi bila vidna. Ravno ko bo minus 10;-)
https://www.thehumanitystar.com/

Fix me! :>

Plus, zdej vemo kako popravit pokvarjeno temo. :D

WarpedGone je 6. mar 2018 ob 00:52 izjavil:

Par besed okol komplikacij pristajanja

Od Scotta science prispevki so zlo dobri nasploh, se jih splaca pogledat.

zjebana tema, upam, da mi bo zdaj delovalo :)

nope, še vedno super BW-jev post :). Je kakšna rešitev? ST na blockchain? :)

Zanimiv post na redditu glede SpaceX obljub in prednosti.

Setting the score straight on SpaceX and its many absurd promises

Setting the score straight on SpaceX and its many absurd promises

There is a lot to unpack here, but the question seems to be genuine so I will do my best to answer it in good faith. If you take the SpaceX-made numbers directly at their word (take the most optimistic SpaceX estimates possible and the least charitable competition estimates you could dream up), then the number could look like a 2-3x difference. But it's mostly fantasy and the launch numbers are much closer.

For example, looking at Wikipedia, the Ariane 5 has about a $180M launch price with a 11 ton capacity to GTO.

Indeed (actually it's probably closer to $160m now, but the general number is correct). However, what this doesn't consider is that the Ariane 5 almost always launches a double-manifest mission: two satellites in one go to GTO. The upper slot costs something like $100 million and can weigh more than the 5.5 mT that Falcon 9 reusable can lift to a nominal GTO (more on this later, because this point is actually a bit subtle), which is more expensive than Falcon but also requires more capacity (you'd be launching that at Falcon Heavy listed prices, i.e. nominally $90 million a pop). The lower berth costs on the order of $60 million, which is perfectly price competitive with Falcon and while it is well below Falcon's max lift capacity it is about the size of a lot of sats that actually go on Falcon that could go on Ariane instead.

And as I'm already talking about Ariane 5, I'll take the opportunity to also mention factors that are not price-related that might lead you to choose Ariane. This post was linked earlier in the thread that laid out in brief a lot of reasons that would lead you to favor Ariane 5 over Falcon 9. If you consider them in some depth you might see that all this might quickly become more significant than nominal launch costs.

But as a nice little case study, I'll cover one of those issues just to show how much it can mean in terms of profit: the GTO -1500 option (as opposed to nominal GTO -1800). Ariane being closer to the equator, you will have to expend significantly less fuel in transferring from GTO (185km or closer x 35786 km at >0 degrees) to operational GEO (0 degrees 35786 km circular orbit), which will extend the lifespan of the satellite by a couple of years (usually but not always, it's the fuel reserves on a GEO satellite that give out first, so decreasing fuel usage extends its life by a lot). That's something that Falcon can do extremely suboptimally - four tons expendable, like three tons with recovery, using a bielliptic transfer which significantly increases the time until a satellite is operational (more on that later) - whereas Ariane 5 gets that basically for free (by being close to the equator). For perspective, a year of satellite life can be reasonably estimated to be worth about $100 million of revenue and depending on the efficiency of your operation, up to about 50% in profit (but I usually see around 30%).

Now I noticed you didn't even mention the other commercial craft that have to be considered: Atlas, Soyuz, and Proton.

Atlas is notably more expensive, but also quite cheap on insurance and can optimize even better than Ariane to get you in whatever orbit you like - including having the option to burn to depletion in a GTO optimization to squeeze out the last bit of life of the upper stage to extend the life of the sat on orbit by more than they can nominally promise upon launch (by months at least). Usually more expensive, but with high-fidelity missions, utterly tiny delays in launch (average of weeks instead of years or months), and a phenomenal reliability record, it and the successor Vulcan are likely to see more successes in the commercial industry in the near future as the high-fidelity launch provider for expensive sats.

Soyuz is launched from Baikonur or Kourou with a fairly moderate payload (8 mT to LEO or about 3-3.5 to GTO), but is dirt cheap even compared to Falcon (could cost the Russian gov something like $25m for a single launch) and even when you have to ship it to Europe it can give you small launches (which again, might have been launched on F9) for really cheap. Or, given it has military-grade orbital maneuverability (something Falcon really does not have because of its rather low-tech upper stage), it can pretty much do any of the orbital missions with rather impressive performance for a craft so small - for example it can launch double Galileo (European navigational sats akin to GPS), single GLONASS (Russian GPS) or GPS sats to MEO (or a commercial payload to the same like the O3b launch a few days ago). Whereas for perspective, Ariane 5 launches four Galileos in one load (while costing well over double), and Falcon 9 or Atlas V base version would launch only one GPS to orbit at a time. And Soyuz has the truly impressive reliability record of 98% over 1300 or so launches in 50 years. A good reminder that viable cheaper-than-Falcon options exist.

And then we also have Proton, which has pretty comparable price to Falcon 9 (can be even lower with current discounts) and which also has the same military-grade maneuverability as Soyuz (and slightly below that of Atlas). Indeed, it can do a good 6.2 mT to a GTO -1500 orbit, which for the biggest payloads it's meant to carry it would be competing not with F9 but with Ariane 5's upper berth or the $90 million FH 8.0 mT price - and for reference all the commercial sats booked for FH could use either of those other options. Currently experiencing a lull in orders because the Russian govt explicitly said they're going to be launching less in the near future (they have big science projects coming up and need to revamp their quality control on Proton, which means expensive delays in launch) and because insurance prices are not the best (this is going to go down very quickly if they can launch a few more successful missions in a row). Also notable is the release of Proton Medium, which reduces prices by a lot and is suitable for the Ariane 5 "lower berth" cargoes.

If you look at all that, F9 becomes just "an option" rather than "a clear winner" for commercial missions. Which is exactly what it is. Ariane 6, Vulcan, Soyuz-5, and Angara also all open up new options for launch that reduce prices and offer upgraded capabilities, whereas it seems like the SpaceX side offers the promise of huge savings on reusability, or pie-in-the-sky fantasies like BFR, as their future. And as I mentioned, reusability only leads to significant savings if you have enough launches to justify it, whereas the market looks to be heading towards a significant lull instead.

Now if I'm not wrong you're saying that despite this massive difference in launch price, if you consider all other variables (insurance costs, special requirements, etc.) this massive price difference is narrowed to only a "couple million dollars"?

Does that mean that customers on average will be spending substantially more on secondary costs on the Falcon 9 than with the Ariane 5? Can this be quantified with an example?

I hope I've covered this to an extent that gives you some additional perspective and narrows the numbers down by a lot. I'll also take the opportunity to mention the factor of delays and how much it matters. When a rocket explodes with sats on board and has to take months off of service, you start to have substantial schedule slippages. And I'd vaguely estimate the cost of a delay as something like one percent every few months of the cost of the entire revenue stream of the satellite over its lifespan. That revenue stream is in the billions. I've seen this one be priced at something like $30 million for fairly moderate delays, but some SpaceX delays (largely due to its two launch failures, but even besides those they can never keep a schedule) have been severe and can be multiple years. On the other side of the spectrum is ULA (Atlas V) with delays on average of about two weeks, and everyone else generally in the range of months.

Why I wanted to mention this separately is to also talk about the fact that the GTO -1500 option of SpaceX - to do a bielliptic transfer - increases the time to perform the transfer to a geostationary orbit by weeks to months. That kind of wipes out a lot of the advantage of doing that transfer in the first place and while you still might come out ahead, Ariane or Proton or Atlas all do it way better. Increasing lifespan by a few years matters, but so does getting your sat into an operational orbit to get your revenue stream going as fast as possible.

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[–]TheNegachin[S] 9 points 6 days ago*

Compare that to the Falcon 9 which has about a $60M launch price with 8 ton capacity to GTO.

Ah, now that is a double-fraudulent statement. Fraud number one is that that $60 million is is the nominal price for a reusable launch to a GTO -1800 orbit. That would be 5.5 mT, rather than 8.0 mT. Fraud number two is that the 8.0 mT is their prediction for Block 5 maximum performance, rather than current performance on the currently operating F9 variants. Couple that with that there are always additional costs for any mission that isn't trivial and you can add some millions to that nominal launch price. In reality launching something like a 5 mT sat on a Falcon 9 might come with a price tag of $80 million plus insurance - although if you want to know the real prices you should probably ask one of the companies that buy those sats. Worth noting is that SpaceX's margins are utterly miniscule even with 100% success, so this suggests they are price dumping in search of increased market share rather than making a business out of it. Sure, the competitors have to lower their prices to relatively middling levels to compete, but ultimately that just sort of means that you are just giving discounts to your SES's and your Eutelsats by making launch providers charge less.

Also is there anything to be gleaned from the fact that SpaceX has over 50% market share for commercial launches in 2018 compared to only 5% in 2013?

First red flag you should notice is that graph was made by SpaceX. Even in the article you posted it is credited to them. And I don't even know where to start in trying to explain how wrong that graph is. Maybe I can link this page on GEO sat procurement that if you scroll through, you will find that Ariane 5 wins quite a few more contracts than SpaceX does in the most recent few years. GEO sats may not be the entire market (they sometimes are the majority, but that may change), but if we're talking about other markets (LEO, milsat, etc) we have to consider that other craft (PSLV, Soyuz, Atlas V, Delta IV even) beat out F9 by quite a lot in quite a few niches. And even then I really have a hard time figuring out exactly how they made that graph, because even if I were to try to cherry-pick the most favorable numbers imaginable I'd have to really stretch to make the graph look like that.

My guess is that they're probably emphasizing how many times they launched in 2017 and plan to launch in 2018. That is a multiple-year backlog they are clearing as a result of launch failures in both 2015 and 2016 plus the tendency of SpaceX to make decisions that led to significant delays in the past. They are winning significantly fewer missions than they won early in their existence (due to offering huge discounts for those that put up large deposits for future launches back when F9 just came out), as what looked like a promising early option turned into just another potential launch provider with some benefits and plenty of downsides.

Credit where credit is due, they do offer a launch service that gives a pretty good amount of lift capacity for its price. Those who are constrained by capital (e.g. very poor countries) may very well decide it's worth curtailing their revenue stream to save money they don't really have. NASA or other government entities always want savings, so they might be willing to take risks as well. But the marketing hype substantially exceeds the actual merit of Falcon 9 as a carrier rocket.

To my layman's eye this seems significant.

You will find that this tends to be SpaceX's MO: using clever marketing to twist the facts to their favor in a manner which is quite clearly fraudulent to anyone who actually goes through the motions of verifying their claims. Which is tough unless someone spells it out because there is a lot to unravel. I hope I've offered enough perspective to see why the result is not really as it first seems.

Kje?