Многоразовость как бизнес кейс

[Apollo13]

korund пишет:
РЗТ - что означает?

Располагаемый запас топлива.

[Pretiera]

korund пишет:
РЗТ - что означает? В списке аббревиатур на форуме не нашёл.
Если это связано с увеличившийся массой бака, то тогда надо и учесть отношение массы топлива к массе ступени.

такой умный, а еще о ГЛА-космолете мечтает))))

[Max_Z]

Apollo13 пишет:
Где-то было что по результатам осмотра двигателей вернувшейся ступени уже внесли изменения в конструкцию Мерлина.

Вот Маск в конце концов и сделает надёжный многоразовый керосиновый движок...
вторая севшая ступень, думаю, будет использоваться в качестве очередного кузнечика, может быть две ступени... а вот третья или четвёртая уже полетит во второй раз....достаточно логичная схема.
И если будут кузнечиковские тесты не на высоту, а на дальность полёта  - можно сказать, что Маск замахнулся на новый диаметр...
а тесты на дальность логичны... допустим, выполнить только первой ступенью (уже летавшей) стандартную циклограмму полёта - старт с Канаверала, достижение соответствующей высоты и скорости, возврат на сушу...

[Salo]

https://spaceflightnow.com/2016/03/31/spacex-hopes-to-sell-used-falcon-9-boosters-for-40-million/

SpaceX hopes to sell used Falcon 9 boosters for as low as $40 million             
March 31, 2016 Stephen Clark

 
The Falcon 9 first stage booster recovered after a Dec. 21 launch at Cape Canaveral is seen inside SpaceX's hangar in Florida. Credit: SpaceX

SpaceX intends to cut the price of a Falcon 9 rocket launch by up to 30 percent when flying with reused first stage boosters, an achievement the company still hopes to demonstrate before the end of the year, SpaceX's president said recently.
That figures to approximately $43 million per flight, a reduction from the Falcon's commercial rate of $61 million published on SpaceX's website.
Gwynne Shotwell, SpaceX's president and chief operating officer, said earlier this month that the company might fly a previously-flown Falcon 9 booster stage later this year.
She said the 15-story first stage booster that returned to Earth in December after a Falcon 9 launch with 11 Orbomm communications satellites weathered the up-and-down trip without major issues.
"The key is to design a system that you don't need to refurbish (between missions)," Shotwell said March 9 in a panel discussion at the Satellite 2016 industry conference and trade show near Washington, D.C.. "The key is for us to have zero refurbishment.
"Now, we've got to inch ourselves toward that, but I took a look at the vehicle that we landed in December ... and you pull off the tunnel covers, and that wire harness is pristine," she said. "The metal is still shiny. You pull off the thermal protection system that we call the 'dance floor' near the engines, (and) that engine is beautiful. It's perfectly clean."
SpaceX engineers transported the flown rocket stage from its landing zone at Cape Canaveral Air Force Station a few miles north to the Falcon 9's Complex 40 launch pad for a brief engine firing in January, less than a month after its Dec. 21 flight for Orbcomm.
"Getting that stage back and taking a look at it, it was extraordinary how great it looked," Shotwell said. "In fact, we didn't refurbish it at all. We took a look at it and we inspected it (before moving it to the launch pad)."
SpaceX does not plan to fly that rocket again, and the company hopes to surmount troubles with landing the Falcon 9 first stage on an offshore recovery barge in the coming months. The Falcon 9 booster has not nailed a smooth touchdown on the football field-sized landing vessel in four tries.
The last two attempts failed due to a broken landing leg and an exceptionally high-speed descent, which was required after lifting the heavy SES 9 communications satellite into a lofty high-altitude orbit March 4.
Another barge landing attempt is expected after the next Falcon 9 launch April 8, which will haul a Dragon cargo ship into orbit for the International Space Station.
 
A Falcon 9 first stage descends to a crash landing on SpaceX's offshore recovery barge after a Jan. 17 launch from California. One of the booster's four landing legs buckled at touchdown, causing the rocket to tip over. Credit: SpaceX

"The plan is obviously to try to recover every one," Shotwell said. "We won't recover every one. We didn't recovery the one from SES 9, although we didn't expect to either. The LEO (low Earth orbit) missions are relatively easy to recover. The GTOs (missions to geosynchronous transfer orbit) are more difficult, but it depends on the size of the satellite, of course.
SpaceX introduced an upgraded version of the Falcon 9 rocket with the Dec. 21 launch. The revised rocket configuration has larger fuel tanks and burns super-chilled, densified RP-1 kerosene and liquid oxygen propellants, allowing the launch team to pump more of the commodities into the launcher.
The Falcon 9's Merlin engines also operate at higher throttle settings.
Collectively, the changes allow the Falcon 9 to take heavier payloads into orbit, and still have enough propellant reserve to steer the first stage back to Earth for a controlled landing. For lighter satellites heading for orbits a few hundred miles up, the booster could return to a touchdown on land, while Falcon 9 missions with large telecom satellites going to orbits more than 22,000 miles above Earth will only have leftover fuel to continue on a ballistic arc toward a ship on station in the ocean.
Even then, communications satellites weighing more than 11,000 pounds, or 5 metric tons, push the Falcon 9's lift capability to its limits, making a landing maneuver a tougher technical challenge.
Shotwell offered a prediction at the landing success rate: "I think we'll probably recover 75 to 80 percent of the LEOs and 50 to 60 percent of the GTOs."
SpaceX wants to see more successful booster landings before setting prices for launches with used rocket components, but the price is sure to come down, Shotwell said.
"We obviously need to recover more, and see how many times we can recover the stage before we do that," she said. "My CFO (chief financial officer) would kill me, but the cost of the fuel is $1 million, or maybe even under $1 million. It would be great if the first stage was maybe just 2x or 3x (2 to 3 times the cost) of that."
The rocket's second stage, which has a vacuum-tuned Merlin engine, its own guidance system and flight computers, will still be expendable. The upper stages are left in orbit, or de-orbited to be destroyed in Earth's atmosphere after their missions are complete.
"There is obviously cost there," she said.
As for the price SpaceX hopes to bring to market?
"I'd like to see a 30 percent reduction probably from reuse," Shotwell said. "That would be great."
But one loyal SpaceX customer wants to see prices pushed even lower.
Karim Michel Sabbagh, CEO of SES, one of the world's largest satellite fleet operators, said March 8 at the same conference that his company wanted a reused Falcon 9 flight for half its current commercial rate — about $30 million.
SES chief technology officer Martin Halliwell told reporters at Cape Canaveral on Feb. 23 that SES is eager for the Falcon 9 to take the leap from recoverable to reusable.
"The answer is SES would have no problem in flying a reused first stage," Halliwell said. "Absolutely no problem. If it's flight-worthy, we're happy with that ... We'll look at it from a technical point-of-view, and from a financial price point-of-view as well. If that all fits into our contract, we have no problem with that."
Halliwell said he does not expect SES to require a demonstration flight of a previously-flown booster before committing an expensive satellite to ride on it.
"I did put out as a challenge to SpaceX that we would be the first satellite operator that would use the same rocket twice to get to (geostationary) orbit," he said. "We discussed that with our investors, and they really liked that. It's something that I would really like to do."
SpaceX is the only major launch company that intends to field a partially reusable orbital-class rocket before the 2020s. Rival United Launch Alliance's Vulcan rocket, intended to replace the Atlas 5, will initially be fully expendable when it debuts at the end of 2019.
By the mid-2020s, ULA aims to develop mechanism to detach the Vulcan's first stage engines to descend via a heat shield and parafoil for mid-air recovery and reuse.
Europe's new Ariane 6 rocket is on pace for a maiden flight by the end of 2020 to begin the phase-out of the workhorse Ariane 5. It will also be used just once.
Arianespace chairman and chief executive Stephane Israel, speaking on the same panel as Shotwell, said his company is staying the course with Ariane 6. The next-generation rocket shares components with Europe's smaller Vega booster, allowing it to launch at as little as half the cost of the Ariane 5.
For geostationary communications satellites launching two-and-a-time on Ariane 6, the translates to prices at around $50 million per spacecraft.
Airbus Safran Launchers, the Ariane 5 and Ariane 6's prime contractor and Arianespace's majority owner, is studying a rocket flyback concept called Adeline that could be the basis for a future European reusable rocket.
Arianespace and SpaceX have won the lion's share of the world's commercial launch contracts in recent years, with both firms reaching a fairly even split.
Israel said Arianespace's plans are buoyed with support from customers, who want multiple launch providers competing in the market.
"Even the best customers go to SpaceX, they go to ILS (International Launch Services), so they know all the suppliers," he said. "They have been very clear. They told us if you are able to diminish the cost by 40 to 50 percent with a modular vehicle, you should have no hesitation — you should go as quick as possible in this direction. So this is our choice, and this choice is fully backed by our customers."
Shotwell repeated an often-told joke that some within SpaceX want to charge more for a flight on a used — or "flight-proven" — rocket.
"That's not what Elon or I want though," she said.
"I encourage you," Israel joked.

[Salo]

http://ria.ru/space/20160409/1405807715.html

Первая ступень ракеты Falcon 9 может повторно использоваться до 20 раз
03:38 09.04.2016 (обновлено: 07:04 09.04.2016)

В пятницу после успешного запуска космического грузовика Dragon к МКС SpaceX впервые удалось совершить вертикальную посадку первой ступени ракеты Falcon 9 на автономную платформу в океане.

© NASA

ВАШИНГТОН, 9 апр – РИА Новости. Американская аэрокосмическая компания SpaceX рассчитывает, что первая ступень ракеты Falcon 9 может использоваться от 10 до 20 раз, а при незначительной модернизации — совершать до ста полетов, заявил глава компании Илон Маск.
В пятницу после успешного запуска космического грузовика Dragon к МКС SpaceX впервые удалось совершить вертикальную посадку первой ступени ракеты Falcon 9 на автономную платформу в океане.
Как сообщил на пресс-конференции после запуска Маск, первый старт вернувшейся в пятницу ракеты может состояться уже в июне. По его замечанию, потенциально первая ступень может совершать еще 10 —20 полетов, а в случае незначительных доработок жизненный цикл может достигать ста космических миссий.
SpaceX в декабре уже совершила успешную посадку первой ступени Falcon 9 на космодром. Ранее сообщалось, что первая вернувшаяся из космоса ракета не вернется к полетам, поскольку представляет для компании особую ценность.
Компания отрабатывает технологию посадки первой ступени ракеты для последующего удешевления космических полетов за счет повторного использования первой ступени.

РИА Новости

[Alex Degt]

Как сообщил на пресс-конференции после запуска Маск, первый старт вернувшейся в пятницу ракеты может состояться уже в июне. По его замечанию, потенциально первая ступень может совершать еще 10 —20 полетов, а в случае незначительных доработок жизненный цикл может достигать ста космических миссий.

Да, а на Марс в 2018, не позжее!

А правда что когда Маск был в Москве ему продали подшивку журнала Техника Молодёжи?  

[Дем]

Экономия и количество повторных запусков.
Если мы примем экономию от повторного запуска за 100% (пусть мы и не знаем, сколько это от общей цены), то:
3й запуск добавит ещё 32%
4й - 18%
5й - всего 10%, и .т.д. по нисходящей.
А износ ступени будет расти.

Т.е. реально больше 4-5 повторов и не имеет смысла.

[Salo]

Peter B. de Selding ‏@pbdes 54 мин54 минуты назад
SpaceX's Falcon 9 reusability plans: What are the real cost savings to customers? http://spacenews.com/spacexs-reusable-falcon-9-what-are-the-real-cost-savings-for-customers/ ...

[Salo]

http://spacenews.com/spacexs-reusable-falcon-9-what-are-the-real-cost-savings-for-customers/

SpaceX's reusable Falcon 9: What are the real cost savings for customers?
by Peter B. de Selding — April 25, 2016
 
SpaceX's Falcon 9 Full Thrust rocket's first stage successfully landed on its drone ship April 8 during a successful mission to deliver SpaceX's Dragon capsule to the international space station. The stage is now undergoing a fresh series of test firings as SpaceX prepares for regular reuse of rocket first stages. Investors, customers and competitors are now assessing how much cost SpaceX can remove fr om its launch price through first-stage reuse. Credit: SpaceX  
 
KOUROU, French Guiana — Now that SpaceX appears on the verge of being the first to reuse rocket hardware since NASA with the U.S. space shuttle, investors and competitors are sharpening their pencils to assess the business case.
The prima facie appeal of reusing rockets has always obscured the challenges of refurbishing, at low cost, a rocket stage and engine bloc that has suffered the stresses of hurtling through the atmosphere in advance of landing.
"It's quite fundamental," SpaceX founder Elon Musk said April 8 after the Falcon 9 first stage made a clean touchdown on a drone ship located offshore the Cape Canaveral Air Force Station, Florida, as part of a successful mission to deliver supplies to the international space station for NASA. The stage has since been returned to port and will be repeatedly test-fired to determine its fitness for reuse as early as this year.
"It's just as fundamental in rocketry as it is in other forms of transport – such as cars or planes or bicycles," Musk said in a post-launch briefing.
NASA engineering veterans of the space shuttle would surely agree about its being fundamental. But after beating their heads against the problem for years, they also would say it's much more difficult than hopping back into your car.
"The SSMEs were reusable," Dan Dumbacher, former NASA deputy associated administrator for exploration systems development, said of the space shuttle main engines. "We tried to make them reusable for 55 flights. Look how long and how much money it took for us to do that, and we still weren't completely successful for all the parts. I want to be realistic: We are not as smart as we think we are and we don't understand the environment as well as we think we do."
Dumbacher was speaking in April 2014, before Hawthorne, California-based SpaceX succeeded in landing the Falcon 9 first stage, first in December on a pad near the launch site, and then during the April 8 mission. But his caution related not to the fact of landing safely, but to the economics of refurbishment.
SpaceX is a privately held company that does not publish its financial statements, making a detailed cost analysis difficult. Outsiders are left with piecing together what they can, based on SpaceX's public statements.
In March, SpaceX President Gwynne Shotwell said the company could expect a 30 percent cost savings from reusing the first stage. If this translated into a 30 percent price reduction to customers, that would drop Falcon 9's advertised price to $42.8 million from today's $61.2 million.
When measured by contract volume, SpaceX's biggest customer is SES of Luxembourg. SES has said repeatedly it is willing to be the inaugural customer for a reused first stage, but would like the price to move closer to $30 million, at least for the first flight.
The interest of SES, a publicly traded company, in rocket reuse has set in motion analyses by investment banks covering the commercial satellite telecommunications industry. The latest is from Jefferies International LLC.
In an April 25 report, Jefferies takes the $61.2 million list price for a Falcon 9 launch and assumes SpaceX makes a gross margin of 40 percent on the launch, leaving a direct per-launch cost to SpaceX of $36.7 million. This includes the costs of the fueled rocket, and of launch campaign.
SpaceX founder Elon Musk has said the first stage accounts for about 75 percent of the total vehicle cost. If the 40 percent gross-margin estimate were correct, that would mean a total first-stage cost of $27.5 million.
Musk has said the first-stage engine could be reused dozens of times. Jefferies assumes it is used 15 times.
If SpaceX passed on to its customers 50 percent of the cost savings, the company could reduce today's Falcon 9 price by 21 percent, to $48.3 million, Jefferies concludes.
If SpaceX gave customers 100 percent of the savings, the launch price would drop by up to 40 percent, to $37 million.
"There are ongoing challenges in translating a reused rocket to tangible capex savings – worries about it failing, insurance implications, retrofitting turnaround, building up a critical mass of reused first stages in the warehouse," Jefferies said. "But the direction of travel is clear."
Musk said the fuel used on a Falcon 9 is between $200,000 and $300,000. Up to 30 percent of the fuel in the first stage needs to be reserved for the landing, which adds mass to the launcher that expendable rockets do not need to worry about. Musk's point is that the cost of the fuel is a non-issue in the overall economics.
While focusing on the first stage, SpaceX would like to return the rocket's fairing as well. "That will certainly help, because each of these costs several million," Musk said.
SpaceX has not addressed how many launches per year it would need to close the business case for reusability. But this is a key issue.
The economies of scale that SpaceX achieves through Falcon 9's design of using identical engines throughout the vehicle – nine on the first stage and one on the second – will likely be diluted once reused first stages are added into the mix.
The amount of dilution will depend on how many times the stages are reused, and what SpaceX can reasonably assume as an annual launch rate.
SpaceX has not publicly disclosed what it views as a minimum acceptable launch cadence.
SpaceX's principal competitor, Arianespace of Europe, sees this issue as a potential death blow for any European attempt to reuse its Ariane rockets. In fact, it's a double whammy for Europe because the same problem that makes it uneconomic for Arianespace makes it necessary for SpaceX to become even more aggressive in the global commercial launch market.
Arianespace Chief Executive Stephane Israel, in an April 23 briefing at Europe's Guiana Space Center here on the northeast coast of South America, said Europe's launch sector can only guess at how much SpaceX will need to spend to refurbish its Falcon 9 first stages.
Israel said European assessments of reusability have concluded that, to reap the full cost benefits, a partially reusable rocket would need to launch 35-40 times per year to maintain a sizable production facility while introducing reused hardware into the manifest.
Arianespace's Ariane 6 rocket, scheduled to debut in 2020, is forecasted to launch 12 times per year starting in 2023, when the current Ariane 5 vehicle is retired.
This rate may increase depending on developments in the commercial market. Seven of the 12 annual Ariane 6 campaigns will be devoted to commercial launches, each carrying two satellites. The five other launches will be for European government customers.
Israel's argument, which he has made before, is that even if first stages can be recovered and refurbished in a cost-effective way, the launch rate needed for maximum cost savings – and hence price reductions to customers – is beyond Europe's reach.
The only nations today whose governments are launching sufficiently often to reach those rates are the United States and China, and even these government markets may be insufficient, in and of themselves, to close the business case.
That means any launch provider introducing reusability will have a maximum incentive to search for commercial business outside its domestic market.
The scenario European launch officials fear is one in which SpaceX succeeds in refurbishing stages at a relatively low cost, and then – to close reusability's business case — becomes even more aggressive on the international market, which is wh ere Arianespace generates most of its revenue.

[Kap]

Если В - 40 % то А*В ни как не даст 36.7 для Ф-9. Очевидно имелось с виду А(1-В).

[knezevolk]

Тут посмотрел ролик о том, какой масштаб имеют "спасательные операции" по 1 и 2 ступени на Восточном.
Это же огромные траты. Временные лагеря, дроны, вертолеты.



В связи с темой вопрос - понятно, что упавшую первую ступень искать легче. Но ведь какие-то работы по ее поиску/обезвреживанию все равно проводятся? И их хотя бы отдаленно можно сравнить с расходами по транспортировке севшей ступени к месту нового старта?

[Валерий Жилинский]

Дем пишет:
Экономия и количество повторных запусков.
Если мы примем экономию от повторного запуска за 100% (пусть мы и не знаем, сколько это от общей цены), то:
3й запуск добавит ещё 32%
4й - 18%
5й - всего 10%, и .т.д. по нисходящей.
А износ ступени будет расти.

Т.е. реально больше 4-5 повторов и не имеет смысла.

Стоимость топлива - понятная величина.
Но почему вы так уверены, что все остальные накладные расходы не могут быть значительно уменьшены? Опыт авиации, прошедшей путь с запуска с пастбища, потом создания аэродромов, позже - аэропортов, а сейчас использующей широкофюзеляжные аэробусы и сеть транспортных хабов по всей планете вас ничему не научил? Изучите вопрос, почему российские компании предпочитают летать на б/у западных лайнерах, а не на отечественных, это тоже полезно.

[Apollo13]

https://www.reddit.com/r/spacex/comments/4ib1rd/fun_with_f9_and_fh_cost_estimates/

[Василий Ратников]

Валерий Жилинский пишет:
почему российские компании предпочитают летать на б/у западных лайнерах, а не на отечественных, это тоже полезно.

не конкретно в укор а так наблюдение

то что люди часто пишут вопросами на вопрос, или загадками, или как бы секретами, сильно обедняет форумы в интернете. Если есть какая то позиция или знания обозначь тезисно уже понятно будет куда клонишь. Можно будет спорить по существу.

Вот что я например знаю через родственника друга авиамеханика с огромным опытом
1) Удобная компаниям система лизинга без грабительских условий
2) Просто высокая надежность. Стоящий на месте самолет приносит убытки. Наш ССЖ пока не дотягивает.
3) Запчасти. Запчасти к нашим это целый детектив, взяток, откатов, подкатов и иногда очень херовое качество. Западные запчасти доступны, белый рынок, сопровождение и тд. Хотя и стоит денег.
4) Регистрация в оффшоре, ниже налоги.

По этому используют, вроде бы.
Не вижу тут отсылки к многоразовым РН ?

По поводу пасбище - авиахаб, полностью согласен с аналогией. Пора перестать воспринимать РН как петарду одноразовую.

[Дмитрий В.]

Василий Ратников пишет:
2) Просто высокая надежность. Стоящий на месте самолет приносит убытки. Наш ССЖ пока не дотягивает.

Это относится только к самолетам, достаточно долго находящимся в серии. 787, например, до сих пор от "детских" болячек избавиться не может. Кстати, Суперджет в Мексике имел в прошлом, емнип, году налет больше, чем некоторые западные машины.

Василий Ратников пишет:
По поводу пасбище - авиахаб, полностью согласен с аналогией. Пора перестать воспринимать РН как петарду одноразовую.

Пока неизвестно, будет ли многоразовая "петарда" дешевле одноразовой. Опыт авиации на РКТ надо переносить с большой осторожностью.

[Вернер П.]

Дмитрий В. пишет:
787, например, до сих пор от "детских" болячек избавиться не может.

Все как-то казалось что их произвели несколько штук и доводят до кондиции. Оказалось их уже 400 штук летает

[Дмитрий В.]

Плейшнер пишет:

Дмитрий В. пишет:
787, например, до сих пор от "детских" болячек избавиться не может.

Все как-то казалось что их произвели несколько штук и доводят до кондиции. Оказалось их уже 400 штук летает

Капитализм: стремятся получить прибыль любой ценой, выпуская в эксплуатацию сырую машину.

[Валерий Жилинский]

Василий Ратников пишет:

Валерий Жилинский пишет:
почему российские компании предпочитают летать на б/у западных лайнерах, а не на отечественных, это тоже полезно.

не конкретно в укор а так наблюдение

то что люди часто пишут вопросами на вопрос, или загадками, или как бы секретами, сильно обедняет форумы в интернете. Если есть какая то позиция или знания обозначь тезисно уже понятно будет куда клонишь. Можно будет спорить по существу.

Я пытаюсь заставить человека подумать над ответом. Слишком часто отвечают не думая, а ещё чаще читают не думая.

Василий Ратников пишет:
Вот что я например знаю через родственника друга авиамеханика с огромным опытом
1) Удобная компаниям система лизинга без грабительских условий
2) Просто высокая надежность. Стоящий на месте самолет приносит убытки. Наш ССЖ пока не дотягивает.
3) Запчасти. Запчасти к нашим это целый детектив, взяток, откатов, подкатов и иногда очень херовое качество. Западные запчасти доступны, белый рынок, сопровождение и тд. Хотя и стоит денег.
4) Регистрация в оффшоре, ниже налоги.

По этому используют, вроде бы.
Не вижу тут отсылки к многоразовым РН ?

Главные пункты второй и третий, да и первый к ним примыкает. Общее во всех трёх - уменьшение времени простоя на земле и снижение накладных расходов. Да и налоги так же воспринимаются у нас как ещё одна статья накладных расходов.
   
Я просто хочу натолкнуть "читателя" на простую мысль - возможностей снижения накладных расходов на современных космодромах - вагон и маленькая тележка. И превращение пастбища в аэродром, строительство аэропорта для обработки грузов и пассажиров, а затем и формирование транспортного хаба вокруг аэропорта вызвано как раз необходимостью уменьшить накладные расходы.
   
Только самые продвинутые современные космодромы дотягивают до уровня аэродромов конца тридцатых годов.

[Валерий Жилинский]

Дмитрий В. пишет:

Плейшнер   пишет:

Дмитрий В. пишет:
787, например, до сих пор от "детских" болячек избавиться не может.

Все как-то казалось что их произвели несколько штук и доводят до кондиции. Оказалось их уже 400 штук летает

Капитализм: стремятся получить прибыль любой ценой, выпуская в эксплуатацию сырую машину.

Ой, сколько недоделок было в любом сданном к памятной дате объекте в Советском Союзе...

[Alex_II]

Дмитрий В. пишет:
Пока неизвестно, будет ли многоразовая "петарда" дешевле одноразовой.

Дешевле в производстве, в эксплуатации или "вообще"? В производстве может даже слегка дороже будет, ну а "вообще", за один пуск - судя по тому, что великой эпопеи по обслуживанию не предвидится - так дешевле... А впрочем - будем посмотреть, думаю в течение года одна - две первых ступени слетают повторно...