Merlin-1

[Salo]

Делить нужно земную тягу, а не пустотную:
http://www.spacex.com/press.php?page=33

sea level thrust to weight ratio of 92

[Salo]

Кстати Km у Мерлина 1С около 2,5:
http://www.spacex.com/press.php?page=33

Merlin consumes 350 lbs/second of propellant and the chamber and nozzle, cooled by 100 lbs/sec of kerosene

[Salo]

http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/awst/2011/08/08/AW_08_08_2011_p27-354586.xml&headline=SpaceX%20Plans%20To%20Be%20Top%20World%20Rocket%20Maker

SpaceX Plans To Be Top World Rocket Maker[/size]

Aug 11, 2011
 
By Guy Norris
San Diego

While many beleaguered U.S. aerospace manufacturers are trimming back amid continuing uncertainty over the nation's long-term goals, California-based SpaceX is ramping up plans to become the world's largest producer of rocket engines in less than five years, manufacturing more units per year than any other single country.

Outlining SpaceX's ambitious growth strategy, President ­Gwynne Shotwell says a production increase is aimed at supporting the assembly of engines for the coming flurry of Falcon 1 and 9 launches. The company also continues to bolster its workforce, passing the 1,500-employee mark for the first time at the start of August after seeing a 50% uptick in payroll last year.

"We have built about 60 engines so far this year, and will build another 40 by year-end," says Shotwell. Speaking at the American Institute of Aeronautics and Astronautics Joint Propulsion Conference here, Shotwell explains that the eventual "plan is to build up to 400 engines per year, that's our target." The expansion is built on booked revenues of $3 billion through 2017, part of which was earned by orders for 14 new Falcon 9 launches placed "within the last year," she says. SpaceX is also "negotiating three more right now," she adds. The launch manifest lists 40 sold flights, including 33 Falcon 9s, plus five options.

"The momentum increased last year, and hopefully if all goes well we'll be docking with the International Space Station [ISS] in December," says Elon Musk, SpaceX founder and chief technical officer. Describing the planned launch of its second test Dragon spacecraft as its "top priority," Musk says the current plan calls for the third Falcon 9 launch vehicle to place the Dragon in orbit from where it will rendezvous and berth with the ISS on Dec. 9. The Commercial Orbital Transportation Services (COTS) flight is required to clear the way for the first of 12 regular cargo delivery flights ordered under the $1.6 billion Commercial Resupply Services contract NASA awarded the company in 2008.

Following the COTS flight, SpaceX's focus will shift to convincing the U.S. Air Force and National Reconnaissance Office that the Falcon 9 can provide a competitive alternative to United Launch Alliance's Atlas V and Delta IV Evolved Expendable Launch Vehicles. "That's our next big priority after ISS," says Musk, who notes that the company recently began construction of its Falcon Heavy launch site at Vandenberg AFB, Calif. The first Falcon Heavy flight is targeted for 2013.

All Falcon 9 flights up to and including the sixth will be powered by the kerosene/liquid oxygen 95,000-lb.-thrust Merlin 1C, with the Merlin 1C-Vac derivative powering the upper stage. Development of the more powerful, 140,000-lb.-thrust Merlin 1D, which will equip the Falcon 9 from the seventh flight onward, is now underway. More than 150 firings have been accomplished at the company's Rocket Development Facility in McGregor, Texas, since the effort began in February.

Revealing several new details of the 1D, Tom Mueller, propulsion engineering vice president, says the engine is designed to produce 155,000 lb. vacuum thrust and have a chamber pressure at "the sweet spot" of roughly 1,410 psia. "We've also increased the nozzle expansion ratio to 16 [compared with 14.5 on the Merlin 1C]," says Mueller, who adds that the initial engine "is doing better than we hoped." The engine is designed for an Isp (specific impulse) of 310 sec. and has a thrust-to-weight ratio of 160:1. "We took structure off the engine to make it lighter. The engine we shipped [for test] to Texas was a development engine and hopefully the production engines will be even better," he says.

The 1D design incorporates many lessons learned from the earlier Merlins and is of a simpler design with an increased fatigue life. "We've added the ability to throttle between 70% and 100%. Currently we have to shut off two engines during ascent, and on this we will be able to throttle them all," he says. The development will also provide the basis for a 1D-Vac version intended for the second stage of the planned Falcon Heavy. "There are no plans to build a 1E. It's going to be a 1D with the same turbopump."

For SpaceX's longer-term ambitions to deliver cargo and humans to Mars, Musk says plans to develop a "super-efficient, staged-combustion engine" could be made official "later this year, or early next." Although no further details of the engine, variously known as the Raptor or BFE (Big Falcon Engine), are being revealed, the company last year showed a concept for a 150,000-lb.-thrust liquid oxygen/liquid hydrogen engine with an Isp of 470 sec.[/size]

[Петр Зайцев]

BFE - это Merlin 2, а не Raptor. Норрис просто попутал. То же самое насчет "flurry" полетов F1 и F9, в то время как F1e можно сказать совсем сошел с рынка. Я как-то пытался его поправить, когда он опубликовал фотографию абляционного Мерлина и подписал "Merlin 1C". Он поблагодарил, фотография осталась как была, никаких опровержений не опубликовано. Нет смысла связываться, просто надо иметь в виду, что у Норриса могут быть фактические ошибки.

[Ну-и-ну]

Может быть он и в цитатах ошибается и вместо "We have built about 60 engines so far this year" следует читать "We have built about 60 engines so far"?

А то 100 Мерлинов в год с темпом пусков 1-4 Ф9 в год как-то не стыкуются. Даже с гипотетическим темпом 5-6 Ф9 в год не стыкуются.

PS: Может, отбраковывают 80%? Или в Китай толкают?

[Salo]

http://www.spacenews.com/civil/spacex-acknowledges-falcon-engine-anomaly-during-latest-launch.html

Fri, 9 September, 2011
SpaceX Acknowledges Falcon 9 Engine Anomaly[/size]
By Dan Leone

      WASHINGTON -- Space Exploration Technologies (SpaceX) Corp. acknowledged that its Falcon 9 rocket experienced an engine anomaly during its December launch of the company's reusable Dragon space capsule.

    "I'd call it an oxidizer-rich shutdown," former NASA astronaut Ken Bowersox, SpaceX's vice president of astronaut safety and mission assurance, told Space News in a Sept. 9 interview. "So because of that, when you get that mixture change happening, the temperatures can go up higher than you want inside the gas generator."

    Bowersox added that "those temperatures could have damaged the turbines in the turbopump." That presents an obstacle for SpaceX, which eventually intends to reuse the nine Merlin engines that power the Falcon 9.

    Despite the engine anomaly, Falcon 9 successfully delivered Dragon to orbit during the Dec. 8 mission, an orbital demonstration flight conducted under NASA's Commercial Orbital Transportation Service (COTS) program.


    SpaceX spokeswoman Kirstin Brost Grantham said that the anomaly poses no threat to the company's upcoming COTS demonstration, a flight to the international space station (ISS) targeted for late November. If that flight goes well, SpaceX would begin making periodic supply runs to the ISS under a $1.6 billion contract NASA awarded the Hawthorne, Calif.-based company in 2008.

    Bowersox's acknowledgement to Space News that the Falcon 9's main stage experienced an oxygen-rich shutdown came after a discussion of the incident during a joint meeting of the ISS Advisory Committee and the NASA Safety Advisory Panel at NASA headquarters here earlier the same day. The meeting was held to discuss the results an Aug. 9 meeting with SpaceX and Orbital Sciences Corp., another company under contract to fly cargo to the ISS.

    During the August meeting, held at the Johnson Space Center in Houston, SpaceX told to the two advisory bodies that there had been an engine anomaly during the most recent Falcon 9 launch, according Charles Daniel, a shuttle and space station safety expert at Herndon, Va.-based Valador Inc., and a member of the ISS Advisory Committee.

    "There was no explanation or root cause analysis or corrective action for this particular anomaly," Daniel said Sept. 9 during the public meeting. "This is a relatively troublesome statement not to recognize that a premature engine shutdown was a significant event."

    Valador Inc., was sued in June by SpaceX in Virginia's Fairfax County Circuit Court. SpaceX brought the suit forward after another Valador vice president, Joseph Fragola, made what SpaceX said were defamatory statements about the safety and reliability of the Falcon 9.

    The suit was settled out of court in early August.

    According to SpaceX's complain, Fragola on June 8 emailed Bryan O'Connor, then NASA's chief of safety and mission assurance, saying he was trying to verify a rumor that the Falcon 9's first stage experienced a significant anomaly during its Dec. 8 mission.

    "I have just heard a rumor, and I am trying now to check its veracity, that the Falcon 9 experienced a double engine failure in the first stage and that the entire stage blew up just after the first stage separated. I also heard that this information was being held from NASA until SpaceX can 'verify' it," Fragola wrote O'Connor, according to court papers.[/size]

[Salo]

Из далёкого 2005 года:
http://www.spacekb.com/Uwe/Forum.aspx/space-policy/2348/Test-Failure-of-SpaceX-Merlin-VTS1-221Engine

Test Failure of SpaceX Merlin VTS1-221Engine[/size]

scottlowtherAT@ixDOT.netcomARGH.com - 12 Sep 2005 19:12 GMT
Got this in an email:

SpaceX attempted a full Mission Duty Cycle (MDC) test of the Merlin S/N 003 engine on Wednesday, 7 Sep 05 with catastrophic results.

At T+158 seconds the chamber and nozzle separated from the engine, breaking several mounts including one of the pitch/yaw actuators and one of two struts which attach to the TPA.  Joints in the fuel lines from the TPA to the engine injector and the gas generator were separated causing fuel to be sprayed around the test stand for just a short time (probably less than 1-2 seconds) but sufficient to burn for 10-15 minutes.

Most of the ablative chamber/nozzle was found in pieces beyond the flame duct.  The throat and upper part of the divergent section of the nozzle, surprisingly, were found intact at some distance away.  It appears that the proximate cause of the failure was that the ablative chamber separated from its attach ring.  The ring is still firmly attached to the engine.  A flange, which is part of the engine dome and keeps the chamber centered on the engine when attached, appears to have been torn away.  In the attached picture you can see the attach ring on the top of the chamber/nozzle as it was being assembled to the engine yesterday.  The red colored RTV-covered ring on the bottom of the engine proper is the flange described above.

It looks like when the chamber started to come off that the side forces generated were sufficient to break the strut and pitch/yaw actuator attach points and the engine swiveled into the TPA causing fuel lines to break, damaging the TPA, and tearing apart the turbine exhaust and roll control nozzle.

Technicians are evaluating now the damage done to facility wiring, tank insulation, and valves.  It may take two weeks to repair the damage and get the stand back in shape to test a Merlin.  The next Merlin engine is in El Segundo waiting for an engine computer to complete acceptance testing and might ship as early as next Monday.  In the meantime SpaceX intends to press with Kestrel testing which should be largely unaffected by the Merlin problems.[/size]

[Потусторонний]

2.1.1 Grasshopper RLV
2.1.1.1 Description
The Grasshopper RLV consists of a Falcon 9 Stage 1 tank, a Merlin-1D engine, four steel landing legs, and a steel support structure. Carbon overwrapped pressure vessels (COPVs), which are filled with either nitrogen or helium, are attached to the support structure. The Merlin- 1D engine has a maximum thrust of 122,000 pounds. The overall height of the Grasshopper RLV is 106 feet, and the tank height is 85 feet.

The propellants used in the Grasshopper RLV include a highly refined kerosene fuel, called RP- 1, and liquid oxygen (LOX) as the oxidizer. The Grasshopper RLV has a maximum operational propellant load of approximately 6,900 gallons; however, the propellant loads for any one test would often be lower than the maximum propellant load. Even when the maximum propellant load is used, the majority of the propellant would remain unburned and would serve as ballast to keep the thrust-to-weight ratio low.
Update: Other items from the document: p.13 -
SpaceX anticipates that the Grasshopper RLV program would require up to 3 years to complete. Therefore, the Proposed Action considers one new permit and two potential permit renewals
p.15 -
The FAA/AST has assumed that SpaceX would conduct up to 70 annual suborbital launches of the Grasshopper RLV under an experimental permit at the McGregor test site. This estimation is a conservative number and considers potential multiple launches per day and potential launch failures.

To support the Grasshopper RLV operations, SpaceX proposes to construct a launch pad and additional support infrastructure at the McGregor test site
p.16 -
2.1.1.3 Flight Profile (Takeoff, Flight, and Landing)
The Grasshopper test program expected to be conducted under an experimental permit would consist of three phases of test launches, which would be performed in the sequence detailed below. SpaceX would repeat tests under each phase as necessary until SpaceX is ready to proceed to the next phase. Multiple test launches could occur each day during daytime hours only, and would be consistent with SpaceX's lease with the City of McGregor. For example, SpaceX is prohibited from conducting engine tests between the hours of 12:00 a.m. and 7:00 a.m. per SpaceX's lease with the City of McGregor.

Launch Phases 1 and 2: Below-controlled-airspace VTVL
The goal of Phase 1 is to verify the Grasshopper RLV's overall ability to perform a VTVL mission. During a Phase 1 test, the Grasshopper RLV would be launched and ascend to 240 feet AGL and then throttle down in order to descend, landing back on the pad approximately 45 seconds after liftoff. The Grasshopper RLV would stay below Class E Airspace (700 feet AGL). In Phase 2, there would be slightly less propellant loaded, a different thrust profile, and the maximum altitude would be increased to 670 feet, still below Class E Airspace. The mission duration during Phase 2 is again approximately 45 seconds.

Launch Phase 3: Controlled-airspace VTVL (maximum altitude)
The goal of Phase 3 is to verify the Grasshopper RLV's ability to perform a VTVL mission at higher altitudes and higher ascent speeds and descent speeds. To achieve this, the maximum mission altitude would be increased from 670 feet incrementally up to 11,500 feet. The altitude test sequence likely would be 1,200 feet; 2,500 feet; 5,000 feet; 7,500 feet; and 11,500 feet. The maximum test duration would be approximately 160 seconds. The Grasshopper RLV would land back on the launch pad.

http://www.hobbyspace.com/nucleus/index.php?itemid=32669#c
http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20110922%20SpaceX%20Grasshopper%20Draft%20EA.Final.pdf

[Salo]

Дают заднего?
122000 было у виртуального Мерлин-1С+.

[Потусторонний]

http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20110922%20SpaceX%20Grasshopper%20Draft%20EA.Final.pdf

2.2 No Action Alternative
Under the No Action Alternative, the FAA/AST would not issue an experimental permit to SpaceX for operation of the Grasshopper RLV at the McGregor test site. Existing SpaceX activities would continue at the McGregor test site, which include engine testing for the Falcon 9 launch vehicle. SpaceX averages approximately five Merlin-1D tests per week as well as six Falcon 9 Stage 1 tests per year. The Falcon 9 is an expendable launch vehicle that uses RP-1 and LOX for propellants. Stage 1 of the Falcon 9 holds approximately 38,700 gallons of LOX and 24,900 gallons of RP-1, for a total of approximately 63,600 gallons of propellant. Stage 1 is powered by nine Merlin-1C engines, with each Merlin-1C engine producing 90,000 pounds of thrust.

As mentioned in Section 2.2, SpaceX currently conducts engine tests at the McGregor test site. SpaceX averages approximately five Merlin-1D tests per week as well as six Falcon 9 Stage 1 tests per year.

[Salo]

Видимо Мерлином-1D теперь кличут прежний Мерлин-1С+:
http://www.spacex.com/falcon9.php

Sea Level Thrust :    556 kN (125,000 lbf)
Vacuum Thrust:    617 kN (138,800 lbf)
Sea Level Isp:    275s
Vacuum Isp:    304s

[Потусторонний]

Видимо Мерлином-1D теперь кличут прежний Мерлин-1С+:]

ИМХО главное отличие 1D - throttle range.

[чайник17]

Дают заднего?
122000 было у виртуального Мерлин-1С+.

Может просто дефорсирован под (сильно)многократное использование?

[Космос-3794]

Из апрельского интервью Маска (по моему в этой теме не было):

What can you tell me about the upgrade under way to the Falcon 9's Merlin-1C engine and how it will streamline production?

The hardest part of the engine to mass produce is the electro-plating of nickel cobalt on the chamber. We create this thick metal jacket that takes the primary stress of the pressure vessel and it's plated one molecule at a time. Plating is about the slowest way you can make a metal thing. With the Merlin-1D we take a metal jacket that is explosively formed. We take a metal sheet that's in a cylindrical form and put it in a bucket of water, effectively. Sort of a concrete pool. And you set off an explosive and the jacket just goes "boohmp" and forms to the outer side walls into a jacket shape, so you have a mold, effectively. And then you just put the jacket on the chamber and braise it on. You can do several a day. We have a fully integrated engine and it's being test-fired right now. There's really not a lot of question marks remaining about the Merlin-1D.

 

What is the capability of the Falcon 9 with the Merlin-1D vs. the Merlin-1C?

It depends on how much sandbagging you want to give on the Falcon 9 performance but it's in the roughly 13-tons-to-low-Earth-orbit capability with the upgraded Falcon 9. The current Falcon 9 is in the 10- to 11-metric-ton class.

 

When will the upgraded engine fly?

The Merlin-1D will fly mid-2012. It could be a Commercial Resupply Services mission or it could be an Orbcomm mission, but it'll be approximately flight seven.

http://spacenews.com/profiles/110425-elon-musk.html

[SpaceR]

http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20110922%20SpaceX%20Grasshopper%20Draft%20EA.Final.pdf

2.2 ...
Stage 1 of the Falcon 9 holds approximately 38,700 gallons of LOX and 24,900 gallons of RP-1, for a total of approximately 63,600 gallons of propellant.

:shock:
Соотношение 1,55 ??
Ну это вообще ни в какие ворота. (

[Дмитрий В.]

http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20110922%20SpaceX%20Grasshopper%20Draft%20EA.Final.pdf

2.2 ...
Stage 1 of the Falcon 9 holds approximately 38,700 gallons of LOX and 24,900 gallons of RP-1, for a total of approximately 63,600 gallons of propellant.

:shock:
Соотношение 1,55 ??
Ну это вообще ни в какие ворота. (

Массовое - где-то 2,1-2,2 получается. :roll: В КС должно быть чуть больше, т.к. часть керосина уходит в восстановительный ГГ.

[SpaceR]

Да, я тоже насчитал ~2,14 общее (при плотности керосина RP-1 0,82).
Но если верить вышеприведенной оценке Salo, камерное составляет ~2,5.
Так что - выходит, на работу ТНА тратится больше 14,5% бортового запаса керосина?  :shock:
М-дяаа...  :roll:
А если его и дальше зафорсировать...

З.Ы. Кстати - с учетом того, что

1 американский галлон = 3.78541178 литра

, выходит что масса топлива в таких баках составит 165,5+77,3 т , то есть почти 243 тонны.
Я думал, что на 3,5 тонны больше (по другой оценке - даже на 6 тонн).
Так что паззл Фалкона-9 сложился теперь немного по-другому.

[Дмитрий В.]

Но если верить вышеприведенной оценке Salo, камерное составляет ~2,5.

Я бы оценил ближе к 2.25...2.3. Все же 2,5 - это более характерно для ЖРД с давлением в КС 120-150 атм.

[Salo]

У РД-107-108 Км =2,39-2,47 при давлении около 60 атм. И это при наличии завесного охлаждения.

[Петр Зайцев]

На Facebook-е опубликовали фотографию прожига Merlin-1D на новом стенде. Первое, что бросается в глаза - сопло снаружи гладкое, упрочнительные кольца исчезли. И еще, кажется, топливный коллектор сместился вниз сантиметров на десять, но тут я не уверен.

https://www.facebook.com/photo.php?fbid=10150872830085131&set=a.10150303260090131.563831.353851465130&type=1&theater