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10 декември 2007

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Dragon Engineering Unit – Aluminum isogrid pressure vessel, heat shield support structure at bottom, Space Station common berthing adapter ring at top, and carbon fiber nose cap at right

In addressing NASA’s requirements, we submitted a package of 486 documents covering every aspect of the F9/Dragon – design, engineering, testing, manufacturing and flight operations. In terms of overall design maturity of the Falcon 9 project, we are ahead of the curve for a typical program of this size. It is unusual for a CDR to feature this quantity of hardware in fabrication, assembly, integration and test phases.

Some progress highlights:

* About 95% of F9/Dragon drawings (actually 3D CAD models) released

* First stage:

o Propellant tanks passed pressure and leak tests

o Thrust structure and composite skirt proof tested

o Plumbing and wiring for all nine engines installed

o First stage fully assembled and lifted atop the big test stand

o Stage and test stand cold flow tests completed

o Electrical, data and sensor system integrity verified

* Merlin 1C regeneratively cooled engine finished development, now in qualification phase

* Avionics architecture developed; triple redundant for F9, and quadruple redundant for Dragon

* Avionics board level testing underway, including flight and engine computers, valve controllers, communication systems, power, lithium polymer batteries, etc.

* Wind tunnel testing completed

During the three day review, twenty six speakers from our engineering teams gave thirty two presentations on over two dozen different areas: structures, aerodynamics, propulsion, avionics, communication, as well as the Dragon spacecraft design, ground processing, launch, flight operations and recovery, and more.

We addressed and dispostioned all questions, and successfully met all of NASA’s requirements for the review. The feedback overall was quite positive. As I mentioned above, the CDR is the most important COTS milestone, apart from performing the flight demonstrations for NASA, so it is certainly a relief to have that behind us.

Overall, the Falcon 9 program remains on track for demonstration of cargo delivery to the International Space Station by the end of 2009.

Falcon 9 First Stage Mounted in the BFTS (Big Falcon Test Stand)

In preparation for the stage firing mentioned earlier, the F9 first stage had to be hoisted hundreds of feet into the air by massive cranes and placed on our largest test stand at the SpaceX Texas test facility. The BFTS is truly epic in size and is structurally capable of handling thrust levels of up to 3.5 million pounds – almost half that of the Saturn V Moon rocket. Standing roughly 235 feet, the stand is tall enough to require FAA flight warning lights.

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Falcon 9 first stage being lifted by two massive cranes.

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Ready for test firing

Falcon 9 Wind Tunnel Testing

Over one hundred years ago, the Wright brothers built small wind tunnels to study the aerodynamics of potential wing designs for their first Flyer. Even in this digital age, where we use computers to perform massive and highly detailed simulations of aerodynamic forces, we still look to wind tunnel data to verify and validate our digital models.

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1:33 scale model of Falcon 9 with 17 foot diameter payload fairing

To that end, we recently tested a 5 foot long Falcon 9 model in one of the few remaining wind tunnels capable of moving air at over three times the speed of sound. Built in the 1950’s, the venerable North American Trisonic Wind Tunnel happened to be located just blocks from our old El Segundo headquarters, and provided us with the ability to test a variety of Falcon 9 configurations, including both the large 17 foot fairing design and the Dragon capsule models.

Big Dragon Update

The SpaceX Dragon Spacecraft will carry up to seven crewmembers or over three metric tons of cargo to the International Space Station – and to future private destinations such as those envisioned by Bigelow Aerospace. Like Apollo, Soyuz, and the future Orion spacecraft, Dragon is a capsule design.

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Transparent Falcon 9 with cargo carrying Dragon spacecraft

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Dragon spacecraft in orbit

Some may wonder if the lack of wings represents a step backwards. Fundamentally, for orbital vehicles spending the vast majority of their time in space, the arguments against wings are strong (although for low energy, sub-orbital craft like SpaceShipOne which spend most of their journey in the atmosphere, there are still good arguments in favor of wings).

Wings have a performance penalty on the way up, are useless in the vacuum of space, and become a hazard on reentry, due to the fragile nature of the high temperature material protecting the wing’s leading surface. Also, returning as a glider gives only one chance at a landing. If any problems develop with the control surfaces, you’re out of luck.

Finally, consider how, with years of Shuttle experience, NASA chose to return to a capsule architecture for the Orion lunar spacecraft. Thus, we favor the capsule design for reliable and economical transport to and from Earth orbit.

Dragon on the Road to the ISS

Several months ago, we completed the first of three phases of review required by NASA’s Safety Review Panel (SRP) to send our Dragon spacecraft to the ISS. Over a series of meetings spanning four days at NASA’s Johnson Space Center in Houston, our engineers presented the Phase I plans for sending the cargo version of Dragon to the ISS.

The review covered twenty-three specific hazards, with extra attention paid to the danger of collision – one of the most difficult hazards to mitigate, and generally considered one of the most difficult areas for “visiting vehicles”.

To date, no other group has passed the Hazard of Collision report the first time through, or completed the overall review in such a short time. The fact that we passed in under a week speaks well of our team’s capabilities.

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Dragon spacecraft berthed at the International Space Station

Dragon Details

When we fly the three COTS cargo missions to the ISS, we will also be flight qualifying a huge number of systems that will eventually support passenger space travel. Whether we’re flying cargo or crew, the essential systems for Dragon remain the same:

* A pressurized interior section for the people or pressurized cargo

* An unpressurized service section ring around the base of the capsule

* Protective layers for aerodynamic and thermal forces

* A Passive Common Berthing Mechanism (PCBM) for mating with the ISS

* 18 bi-propellant thrusters for orientation and orbital maneuvering

* Eight propellant tanks and two pressurant tanks

* Redundant drogue and main parachutes

* Base and backshell heat shield

* Micrometeorite shields

* Proximity operations navigation and berthing system

* A trunk section to hold unpressurized cargo, solar panels and thermal radiator

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Overview of the Dragon spacecraft

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Dragon with pressurized section filled with cargo

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Dragon with pressurized section fitted with seats, people and life support

Draco Thrusters Take Shape

We’re developing a small rocket engine called Draco that generates 90 pounds (400 Newtons) of thrust, using monomethyl hydrazine as a fuel and nitrogen tetroxide as an oxidizer – the same propellants used for orbital maneuvering by the Space Shuttle. Dragon will have a total of 18 Draco thrusters for both attitude control and orbital maneuvering.

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Small but efficient – getting around becomes easier once you’re in “zero” gravity

Our propulsion team has completed the first Draco development engine, and it will soon begin testing at our new MMH/NTO vacuum test chamber in Texas.

Dragon Heat Shield Shapes Up

The base heat shield is an extremely important part of Dragon’s design. Although one can do a lot of testing on the ground with plasma torches and arc jets, nothing on the surface of the Earth can test for the actual conditions that are encountered upon reentry at 25 times the speed of sound. Considerable safety margins must be applied to address the model uncertainty, which leads to a relatively heavy heat shield. However, as we are able to anchor our models with empirical flight data, the mass efficiency of the heat shield can be much improved.

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Digital modeling of reentry heating for the Dragon capsule - note how the off-axis heating pattern influences the design of the tile pattern in the photos below

A few months ago we completed the full-scale engineering unit of Dragon’s heat shield. Shaped like the heat shields that protected the Apollo capsules during their high-speed returns from the Moon, Dragon’s heat shield uses phenolic impregnated carbon ablator (PICA), the highest heat resistance material known. At heat fluxes that would vaporize steel, PICA is barely scathed.

Developed by the NASA Ames Research Center, PICA demonstrated its abilities in protecting the Stardust sample return mission. Stardust holds the record for the fastest mission reentry speed – nearly 28,000 miles per hour. Dragon will return at under than a third of that speed.

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Technicians bond PICA tiles to the Dragon non-flight heat shield engineering model

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Completed Dragon heat shield engineering unit with tiles, ready for testing

Dragon Makes a Big Splash

Dragon will return to Earth and land in the ocean (although it can be modified to land on land too). As with the Falcon 9 wind tunnel testing described above, we’re using scale models of our Dragon capsule to verify our digital models of recovery and splash down.

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1:3 scale model of the Dragon capsule drops into the testing pool

This video clip compares computer simulation of splashdowns with actual drop tests of a Dragon model having corresponding weight, impact speed, and drop angle. The model drop tests confirmed our computer simulations within a few percent.

Dragon will be steerable during reentry, allowing us to hit a target zone of under 1 mile in radius. Initial splashdowns will occur off the California coast.

Next Falcon 1 Launch

Since we decided to use the upgraded Merlin 1C engine on Falcon 1, the next flight has been dependent on finishing the development and qualification testing phases of the engine. With development now over, and only two or three months of qualification and acceptance testing remaining, it appears that Flight 3 will occur in the Spring of 2008.

Flight 3 will be followed shortly afterwards by Flight 4, carrying RazakSAT. Both missions will fly from our Kwajalein Atoll launch site in the central Pacific. Be sure to sign up for our email updates to receive our latest launch progress news. (See the upper right corner of our website.)

New Customer

In September, Avanti Communications Group PLC of the UK purchased a Falcon 9 launch for its HYLAS Ka band satellite to geostationary transfer orbit (GTO). HYLAS will provide broadband and data communications services to European customers in 22 countries. Of the seven Falcon 9 launches on the SpaceX manifest, this is our first commercial geostationary telecommunications customer. The contract includes options for up to three additional satellite launches, which if exercised, will total approximately $150 million at our standard list prices.

We’re Looking for Great People

At SpaceX we are always seeking world-class people to join our team. Most of our needs are in California, but we’re also growing our Florida team in preparation for increased Falcon 9 activities at Cape Canaveral, and we’re expanding our Texas propulsion and test team.

Since the people we seek can work anywhere they want and tend to be most highly prized by their organizations, SpaceX also offers up to a $5,000 award to anyone who refers a candidate we hire. Besides a competitive salary, comprehensive benefits and significant stock options, joining SpaceX offers the opportunity to help open up space for humanity.

--Elon--

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  • 2 месеца по късно...
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http://www.nauka.bg/index.php?mod=front&am...e&pid=10720

SpaceX завърши разработката на двигателя Merlin 1C. Това е първия двигател, разработен от нищото в САЩ от десет години и втория от 25 години. Другите два са RS-68 (използва се на Делта IV и ще се използва на Арес V) и SSME - главните двигатели на совалката. Merlin 1C има 347 kN тяга на морското равнище и 400 kN тяга във вакум, специфичен импулс 301 секунди, консумира 136 кг гориво в секунда, охлажда се от 40 кг/сек гориво и може да абсорбира 10 MW топлинна енергия. Двигателят ще бъде използван на ракетите Фалкън 1 и Фалкън 9. Фалкън 1 има един двигател на първата степен, а Фалкън 9 разполага с 9 двигателя на първата степен. Следващият полет на Фалкън 1 е през пролетта, а на Фалкън 9 късно тази година или рано догодина.

Merlin_1C_Falcon_1_engine.jpg

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SpaceX направи тест на Фалкън 9 с три двигателя. Ракетата има 9 двигателя и SpaceX прави тестове със запалване на един, три, пет, седем и девет двигателя. При последния тест бяха запалени три двигателя едновременно. По-късно тази година се очакват тестове с повече двигатели. Първият полет на Фалкън 9 се очаква към края на годината, а след около месец ще бъде изстреляна третата ракета Фалкън 1.

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