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Posts Tagged ‘liquid hydrogen’

NASA Fills Cryogenic Tank One Last Time

Friday, July 8th, 2011

Atlantis shuttle with cryogenic tankToday could be the end of an era—weather permitting—that has captivated the nation’s attention for the last 30 years. The Atlantis space shuttle is scheduled to launch at 11:26 a.m. on July 8. With shuttles launching every few months, it may not seem like much. It’s the 135th in a storied history of shuttle launches. And it’s also the last shuttle to launch under NASA before the shuttle program closes its doors.

The shuttle program also has a strong connection to the gases and welding industry. Welding has played an important part in building the shuttles and launch pads over the years. In terms of gases, NASA is the largest consumer of liquid hydrogen in the U.S., using approximately 10 million lbs. per year. The shuttle program is a big part of this. The iconic giant orange cylinder you see on every shuttle is a cryogenic fuel tank that stores half a million gallons of liquid hydrogen and liquid oxygen. For the final shuttle, the “tanking” process of filling the orange vessel began at 2 a.m. this morning, and completed just before 5 a.m.

The fact that NASA is able to use liquid hydrogen is an accomplishment in and of itself. The report Taming Liquid Hydrogen: the Centaur Upper Stage Rocket, 1958-2002 states, “The taming of liquid hydrogen proved to be one of NASA’s most significant technical accomplishments…Today, liquid hydrogen is the signature fuel of the American space program and is used by other countries in the business of launching satellites.” Read about the development of hydrogen as a shuttle fuel on NASA’s website.

Other gases play important roles as well. To treat the shuttle’s ceramic tiles, a 350-degree oven is filled with nitrogen, which is then sucked out to create a vacuum. The St. Petersburg Times ran a great article about the shuttle workers, including those who create the tiles…and others who make snowballs from ice that forms on the oxygen lines.

The shuttle program will be missed, but we can only hope that private organizations will continue the great work that NASA has done for many years. If and when they do, they will call on gases and welding to make this happen.

Follow along on Twitter @GasWeldEdge.

Final Countdown Fueled By Gases & Welding

Friday, February 25th, 2011

Discovery takes off for a final timeThursday, February 24 was the final launch for the Shuttle Discovery, which set off on its 39th flight. The final mission represents the end of an era for the space program, and the swan song for a shuttle that is absolutely steeped in gases and welding technology.

To start, the Discovery’s bright orange external fuel tank holds a total of 535,000 gallons of liquid hydrogen and liquid oxygen. The shuttle’s main engines burn the cryogenic propellants to accelerate from 3,000 mph to over 17,000 mph in a matter of six minutes to reach orbit. At that rate, you can bet the engines are burning the gas pretty fast. According to NASA, the engines consume liquid fuel at a rate that would drain an average family swimming pool in under 25 seconds. No wonder they need such a big tank.

As for the gas mix, the Space Shuttle’s main engines operate at a liquid oxygen/liquid hydrogen mixture ratio of 6 to 1 in order to produce 470,000 pounds of vacuum thrust. Because the gases are hydrogen and oxygen, the exhaust is mainly water.

A half million gallons of gas may seem like a lot, but that only accounts for the actual takeoff. NASA goes through a lot of gas in order to test the main engines as well. According to NASA, “Each time a shuttle main engine is test-fired for the 8-½ minutes it takes to launch a Shuttle into orbit, it burns 132,000 gallons of liquid hydrogen and 49,000 gallons of liquid oxygen.”

How does the gas get from Air Products to NASA for these engine tests? By tug boat, naturally. It’s a fascinating five-hour trek that Captain Rocky Pullman has been making for 32 years, and you can read about it here.

In addition to gases, the Discovery was the first shuttle to use longitudinal friction-stir welds on two of the liquid hydrogen tank barrels. Previously, the panels were joined by fusion welding, and the change made a significant improvement to the structural integrity of future shuttles.

As many times as Discovery has taken off into space, it’s always an amazing sight to watch the shuttle take off. And it will never cease to amaze me what we can accomplish with a little welding and a whole lot of gases. Check out a video of the launch below:

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NASA Talks Cryogenic Gases

Friday, January 28th, 2011
Discovery's external cryogenic gas tank

The dark orange external tank is the largest component of the space shuttle stack. It holds 535,000 gallons of liquid hydrogen and liquid oxygen for the shuttle's three main engines.

There was an interesting article this week on GAWDAwiki about NASA, cryogenic gas and Facebook. In short, NASA fielded questions from its followers on Facebook, many of which were about the use of cryogenic propellants. There were a number things about this story that piqued my interest.

First, I think it’s great that so many people have an interest in gases. I definitely learned a lot about their use of liquid hydrogen and oxygen. NASA explains:

“The tank holds about 535,000 gallons of liquid hydrogen and liquid oxygen. Both propellants are cryogenic, which means they are super-cold. The oxygen is chilled and pressurized to minus 297 degrees F in its liquid form and the liquid hydrogen buries the temperature needle to minus 423 degrees F.”

Ever wonder about the filling? Wonder no more:

“The liquid oxygen and liquid hydrogen tanking process begin simultaneously. The process begins by chilling the transfer lines and main engines. Both commodities begin with slow fill to avoid thermal shocking of the aft domes. We then transition to fast fill up to about 98 percent capacity. We slow back down at this point to avoid overfilling. Once filled, we move into a stable replenish flow rate to maintain proper propellant levels and conditioning.

“Regarding the liquid hydrogen tank, we use helium to pressurize the tank for flight. The preburn you mention is actually for the liquid oxygen exhaust at the main engines.”

A look inside the external cryogenic tank

A look inside the external tank shows the junction of the liquid oxygen tank on top and the liquid hydrogen tank on the bottom. The intertank joins the two tanks together to make a complete external tank. Photos via NASA

Now you have a good reason to watch the next shuttle launch! (Check out the launch schedule here.) What questions would you ask NASA about their use of gases?

The second reason this story interested me is because it’s a great use of social media to connect with people and share knowledge. Education is a great way to establish yourself as a trustworthy authority.

In terms of a gases and welding distributor, how are you reaching out to your customers through social media? I’d love to hear any interesting stories you may have involving social media in your business.

Out of curiosity, anybody know who provides those 535,000 gallons of cryogenic gas? I’d love to hear if a GAWDA member is involved.