Marshall Space Flight Center was the featured topic of last night's Live Chat. 66 were in attendance to hear Marshall's Scott Anderson talk about the history and mission of the center. Located in northern Alabama on the grounds of the Redstone Arsenal, Marshall is NASA's premier center for the development of rocket boosters. Launch vehicles for America's first satellite, first astronaut, and first man to the moon were all designed and tested at Marshall.
Marshall is also home to the research command center for the International Space Station. While launch control is at Kennedy and mission control is in Houston, this is where the science takes place (actually, it takes place in space, but here is where the results come). It also has the capability of acting as mission control should severe weather strike Houston.
Find out more by accessing the archive of the chat this weekend in the Live Chat archive off the Discover page, or on Monday in the INSPIRE Archive on the Home Page.
Friday, January 28, 2011
Wednesday, January 26, 2011
J-2X Progress: Valves, Commands into Action
By Bill Greene, MSFC, AL
Everyone seems to like analogies between the composition of a rocket engine and that of the human body. These are often colorful but not always helpful. In some cases, however, they work pretty well.
Okay, so let's start with your body as it is. Now, imagine removing all of your bones. Guess what? You're an immobile lump. Even if your brain is sending signals and your muscles are contracting, you're not really moving anywhere.
This time, let's instead start with your body as it is, but now imagine removing all of the muscles and tendons that connect the muscles to the bone. You've got a central nervous system and you've got bones, but with nothing to flex, the chain is broken and you’re stuck where you sit (assuming that you can still actually sit).
And, of course, if you instead start with your whole self and imagine removing your brain and/or your central nervous system that connects your brain to your muscles, again, you've achieved perfect immobility (i.e., you look like me on Saturday afternoons during college football season).
The point is that in order for you to be up and about, shoveling snow, doing laundry, playing pool, typing, whatever, you need both the command center that figures out what signals to send -- your brain -- and you need things that turn those signals into action -- your muscles and tendons and bones. In a rocket engine, the analogue for the brain is the engine controller. It is a computer that receives instructions from the vehicle and sends out commands to the engine pieces so as to fulfill those instructions. The analogue for the muscles are the valve actuation systems. These are the things that "flex" and cause movement. And the analogue for the bones, the final effectors that make things happen, are the valves.
The controller sends out signals and then the actuation system responds by shuttling pressurized working fluid -- helium for J-2X though some engines use hydraulic fluid instead -- where it needs to go so that the valves move and the engine comes to life. The engine goes from being a lump of inert, shiny metal to a "living" beast of flowing propellants, spinning turbomachinery, lots of fire, and thundering, rumbling thrust.
On the J-2X, there are 42 valves. Most of this number is made up of small valves like check valves, solenoid valves, and valves in small lines like the bleed lines. There are also a handful of big valves -- the primary valves -- that directly control the flow of propellant and, in one case, combustion products along the plumbing of the engine. Each of these primary valves is connected to a valve actuator, i.e., the muscle. These valve actuators convert the energy of high pressure helium gas into mechanical rotation of the valve. This is accomplished by pressurizing cavities and moving pistons and, in this way, the valve is pushed opened or closed. I've used this schematic shown below before, but it is useful here as well since it illustrates the primary J-2X valves: Main Fuel Valve (MFV), Main Oxidizer Valve (MOV), Gas Generator Fuel Valve (GGFV), Gas Generator Oxidizer Valve (GGOV), and the Oxidizer Turbine Bypass Valve (OTBV).
The control logic for J-2X is relatively simple. The whole subject of different kinds of control logic is a good topic for a future article, but suffice it to say that for normal operation the J-2X: starts on command, can change between two power levels on command, and shuts down on command. The control system is designed to do other things as well, including monitoring the health of the engine, but these operations are the commanded functions. Start and shutdown can be simplistically thought of as: the valves open and the valves close. It’s a bit more complicated since the timing of opening and closing is extremely important, but the open/close notion is basically true. The oddball action is the one consisting of changing power levels. That is accomplished by controlling the power to the oxidizer turbine via the OTBV. This bypass valve effectively allows for limited, independent control of the two turbopumps. By altering the power to the oxidizer turbopump (OTP), you can control the engine thrust level (and, simultaneously, mixture ratio).
The OTBV for J-2X is designed and built by Pratt & Whitney Rocketdyne (PWR), the prime contractor for the whole engine. In addition to being responsible for the “oddball action” on the engine of changing power levels, it represents a challenging design due to the range of operating conditions. Unlike the other primary valves on the engine that see, essentially, one narrow range of environmental conditions, the OTBV has to function in temperatures approaching 420 degrees below zero Fahrenheit (liquid hydrogen conditions) immediately prior to start and then, suddenly, within 1 second of ignition of the gas generator, see temperatures approaching 750 degrees above zero Fahrenheit (combustion products). That broad range of operating conditions requires special design considerations and special materials. Not only do you have to worry about wear and tear under such harsh conditions, but you also have to think about simple operation under the extremes of thermal expansion.
The original, Apollo-era J-2 engine also had an OTBV, but it was used slightly differently and was designed much differently. It was a butterfly valve whereas the J-2X OTBV is a ball valve.
No, the valves shown in the picture are NOT rocket engine valves. I can't show any internal workings of rocket engine valves. In fact, I am not even allowed to describe the general design details that make the J-2X OTBV kind of unique. However, the basic elements of rocket engine valve functionality for butterfly and ball valves are essentially the same as these water valves. The biggest difference is the replacement of the handles with pneumatically driven actuators. Back during the Apollo era it would seem that butterfly valves were most frequently used, but after many years of usage on the Space Shuttle Main Engine, ball valves are often preferred these days. They generally require less torque to move and they generate better flow characteristics and flow rate control capability.
The first OTBV unit for use on the upcoming development engine testing for J-2X is in the later phases of manufacturing at the PWR in Los Angeles. All of the individual piece parts are schedule to be complete by the beginning of February and assembly will begin the middle of February. The valve then will be integrated the actuator and shipped to the NASA Stennis Space Center to be put on the first engine.
Everyone seems to like analogies between the composition of a rocket engine and that of the human body. These are often colorful but not always helpful. In some cases, however, they work pretty well.
Okay, so let's start with your body as it is. Now, imagine removing all of your bones. Guess what? You're an immobile lump. Even if your brain is sending signals and your muscles are contracting, you're not really moving anywhere.
This time, let's instead start with your body as it is, but now imagine removing all of the muscles and tendons that connect the muscles to the bone. You've got a central nervous system and you've got bones, but with nothing to flex, the chain is broken and you’re stuck where you sit (assuming that you can still actually sit).
And, of course, if you instead start with your whole self and imagine removing your brain and/or your central nervous system that connects your brain to your muscles, again, you've achieved perfect immobility (i.e., you look like me on Saturday afternoons during college football season).
The point is that in order for you to be up and about, shoveling snow, doing laundry, playing pool, typing, whatever, you need both the command center that figures out what signals to send -- your brain -- and you need things that turn those signals into action -- your muscles and tendons and bones. In a rocket engine, the analogue for the brain is the engine controller. It is a computer that receives instructions from the vehicle and sends out commands to the engine pieces so as to fulfill those instructions. The analogue for the muscles are the valve actuation systems. These are the things that "flex" and cause movement. And the analogue for the bones, the final effectors that make things happen, are the valves.
The controller sends out signals and then the actuation system responds by shuttling pressurized working fluid -- helium for J-2X though some engines use hydraulic fluid instead -- where it needs to go so that the valves move and the engine comes to life. The engine goes from being a lump of inert, shiny metal to a "living" beast of flowing propellants, spinning turbomachinery, lots of fire, and thundering, rumbling thrust.
On the J-2X, there are 42 valves. Most of this number is made up of small valves like check valves, solenoid valves, and valves in small lines like the bleed lines. There are also a handful of big valves -- the primary valves -- that directly control the flow of propellant and, in one case, combustion products along the plumbing of the engine. Each of these primary valves is connected to a valve actuator, i.e., the muscle. These valve actuators convert the energy of high pressure helium gas into mechanical rotation of the valve. This is accomplished by pressurizing cavities and moving pistons and, in this way, the valve is pushed opened or closed. I've used this schematic shown below before, but it is useful here as well since it illustrates the primary J-2X valves: Main Fuel Valve (MFV), Main Oxidizer Valve (MOV), Gas Generator Fuel Valve (GGFV), Gas Generator Oxidizer Valve (GGOV), and the Oxidizer Turbine Bypass Valve (OTBV).
The control logic for J-2X is relatively simple. The whole subject of different kinds of control logic is a good topic for a future article, but suffice it to say that for normal operation the J-2X: starts on command, can change between two power levels on command, and shuts down on command. The control system is designed to do other things as well, including monitoring the health of the engine, but these operations are the commanded functions. Start and shutdown can be simplistically thought of as: the valves open and the valves close. It’s a bit more complicated since the timing of opening and closing is extremely important, but the open/close notion is basically true. The oddball action is the one consisting of changing power levels. That is accomplished by controlling the power to the oxidizer turbine via the OTBV. This bypass valve effectively allows for limited, independent control of the two turbopumps. By altering the power to the oxidizer turbopump (OTP), you can control the engine thrust level (and, simultaneously, mixture ratio).
The OTBV for J-2X is designed and built by Pratt & Whitney Rocketdyne (PWR), the prime contractor for the whole engine. In addition to being responsible for the “oddball action” on the engine of changing power levels, it represents a challenging design due to the range of operating conditions. Unlike the other primary valves on the engine that see, essentially, one narrow range of environmental conditions, the OTBV has to function in temperatures approaching 420 degrees below zero Fahrenheit (liquid hydrogen conditions) immediately prior to start and then, suddenly, within 1 second of ignition of the gas generator, see temperatures approaching 750 degrees above zero Fahrenheit (combustion products). That broad range of operating conditions requires special design considerations and special materials. Not only do you have to worry about wear and tear under such harsh conditions, but you also have to think about simple operation under the extremes of thermal expansion.
The original, Apollo-era J-2 engine also had an OTBV, but it was used slightly differently and was designed much differently. It was a butterfly valve whereas the J-2X OTBV is a ball valve.
No, the valves shown in the picture are NOT rocket engine valves. I can't show any internal workings of rocket engine valves. In fact, I am not even allowed to describe the general design details that make the J-2X OTBV kind of unique. However, the basic elements of rocket engine valve functionality for butterfly and ball valves are essentially the same as these water valves. The biggest difference is the replacement of the handles with pneumatically driven actuators. Back during the Apollo era it would seem that butterfly valves were most frequently used, but after many years of usage on the Space Shuttle Main Engine, ball valves are often preferred these days. They generally require less torque to move and they generate better flow characteristics and flow rate control capability.
The first OTBV unit for use on the upcoming development engine testing for J-2X is in the later phases of manufacturing at the PWR in Los Angeles. All of the individual piece parts are schedule to be complete by the beginning of February and assembly will begin the middle of February. The valve then will be integrated the actuator and shipped to the NASA Stennis Space Center to be put on the first engine.
Tuesday, January 25, 2011
Poll of the Week: Fly Me to the Moon?
Here are some selected comments from the Discussion Board:
I, personally, would wait until I get the feedback of those who have gone there already.
Then, I would be sure about problems and what not, how comfortable it is, and the daily routine.
This would also ensure that I will come back alive!
Yes. Absolutely, positively, definitely, 100.00% yes. When do we leave?
I love the moon! I'll gladly time travel back to the Apollo era and hop aboard the Saturn V! I would like to come home after a while, but a vacation on the moon doesn't sound like a bad idea.
Again, I want to be the guy on Earth controlling that thing/building the rockets. I might go as a short vacation, but...
Well, I would definately go in a heartbeat. But, I would want to come back down to Earth after a while. So, a vacation sounds good.
I'd go there in a heartbeat too! I would be willing to live there as long as I could periodically visit our family, friends, and Earth. It would be so cool to be in a lunar colony!
LOL sure. After all, someone has to build and plan it, or it never gets off the ground.
Just be sure the problem solving guide/instruction manual thing whatever it's called has "Don't Panic" on the cover...
Thanks for participating in our polls, and look for the new poll to be posted Tuesday afternoon!
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| "Orbit Buddy" by =Royaba |
Friday, January 21, 2011
Live Chat Roundup: January 20, 2011
Did you know there is water on the Moon? Did you know there was a LOT of water on the Moon? That discovery and how it was made was presented by Tony Colaprete from the Ames Research Center. Tony is the Principal Investigator for the LCROSS (Lunar Crater Observation and Sensing Satellite) mission and previewed a presentation he will give later this month to a science conference in Israel. 63 members of the INSPIRE Online Learning Community were in attendance for the presentation and the Q&A that followed.
LCROSS piggybacked its mission with the LRO (Lunar Reconnaissance Orbiter), being composed of a modified adapter ring and spent Centaur second stage. LCROSS itself trailed the Centaur, allowing it to impact first into the lunar surface and taking observations which were immediately relayed to Earth. The LRO and Earth based telescopes also imaged the impact. The goal of the impact was to blast surface material into space and make spectrographs of the ejecta. While visually disappointing, a wealth of information was recovered by LCROSS. Tony Colaprete and his team have poured over the data during the year following the impact, and are now releasing their findings: the Moon is wet. This conclusion is verified by other orbiting spacecraft from other countries.
The benefits of finding this lunar water are many. Historically, it helps piece together the Moon's past, giving more information about the creation of the Solar System. Lunar water also offers an in-situ supply for future expeditions. This water can then be broken down to oxygen (needed for life support) and hydrogen (fuel).
If you missed the chat, you can find it in the archives in the Live Chat section off the Connect page, or on Monday in the INSPIRE Archives on the Home Page. DOn't forget to copy the pass code and take the quiz!
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| Visual spectrum image of the LCROSS impact |
The benefits of finding this lunar water are many. Historically, it helps piece together the Moon's past, giving more information about the creation of the Solar System. Lunar water also offers an in-situ supply for future expeditions. This water can then be broken down to oxygen (needed for life support) and hydrogen (fuel).
If you missed the chat, you can find it in the archives in the Live Chat section off the Connect page, or on Monday in the INSPIRE Archives on the Home Page. DOn't forget to copy the pass code and take the quiz!
Wednesday, January 19, 2011
NASA's First Android App
By Jason Townsend
You've probably heard all the hype about Tang being invented as a drink for the astronauts. Well, we hate to say this -- but that's not true. But lots of other amazing technologies have been invented by NASA or through NASA-funded research and now we've got an App for that.
The NASA Spinoff App highlights the direct impact NASA innovations have made on the everyday lives of citizens. Commercialization of NASA technology has contributed to products and services in the fields of health and medicine, transportation, public safety, consumer goods, environmental resources and computer technology.
This is NASA's first Android app and allows you to explore NASA technologies developed in your own backyard. The App contains a feed of NASA’s latest technology news, a searchable database of NASA-derived innovations, a map of spinoff locations, a historical timeline and a database of NASA’s available licensing opportunities to inspire the spinoffs of the future.
Additional Android, iPhone, iPad and other Apps are in the works. We'll continue to keep our list of Apps fully up to date. But in the meantime, explore our newest NASA App and learn about how space technologies are impacting life right here on Earth.
Wednesday, January 12, 2011
Where are the archives?
By INSPIRE Staff
Some of you may want to beef up your point totals for your Summer STEM Experience application by checking out old Live Chats and taking the quizzes associated with them. You’ve come here to the Connect page, clicked the Live Chat link on the left and then selected Archives to find ... nothing! Well, don’t worry; they are still available. The Archives here are bridged directly from the Elluminate website, and yesterday the bridge went down. When we restored it, the links to the archived chats were lost. But, as I said, there is another way!
Navigate back to the Home page and look at the bottom of the left hand column for the “Live Chat Archive” link. There, you will find every chat sorted by month, and even have the option to open up the Elluminate file itself, or download an audio (MP3) or video (Quicktime) version of the chat. Any one will provide you with all the information you need to enjoy the chat and then access the quiz (the password for the quiz will be found at the end of the chat). While the Archive off the Connect page has been a convenience, the official INSPIRE Archive has always been found on the Home Page.
As always, if you have any questions about this, contact INSPIRE support at nasainspire@okstate.edu.
Tuesday, January 11, 2011
Poll of the Week: Favorite Part of the OLC?
This weeks poll asked your opinion on the OLC:
Over half of you chose the Home Page as your favorite part of the OLC. Second was the Discussion Board, followed by the Leaderboard. This blog and the Showcase rounded out the remaining votes. Thanks to all who left their vote!
Though the Discussion Board came in second, it was busy as many posted opinions on their votes. Here are some selected posts:
“My favorite part of the OLC are the fun activities and talking to kids my age who know about science!”
“I also think the Discussion board is the best place in the OLC. I enjoy the activities as well, but the OLC offer us the opportunity to share our knowledge and opinions directly. I have gotten to meet so many interesting people here and I think this is what makes us a group. The discussion board is our way to communicate and contact each other. “
“I think the home page is the best part of the OLC. It not only keeps you aware of activities, chats, and news in the OLC but also talks about what is going on in NASA and space, such as the lunar eclipse, the space shuttle launch, and space weather.”
“I like the Discussion Board because I think it's fun to discuss STEM news and subjects. Many of the discussions we have on here are about subjects featured on the home page, the blog, activities, and chats, so it encompasses a large part of the OLC. It's also fun to see other people's projects, like the Your Spin on Technology projects that are posted on the Discussion Board. It connects the OLC, so it's my favorite part.”
“I believe the best part of the OLC is definitely the leader board. I'm a competitive person, and now that ... I finally have time to get more involved, I'm going to enjoy climbing up those ranks. They add an incentive to work harder, show you where you are in relation to your OLC peers, and are nicely incoporated into a bulletin board design nonetheless. I really like the way the entire site is designed, but the leaderboard adds an extra layer of challenge for me.The home page comes in for a close second, followed probably by the discussion board. The Showcase has some pretty neat programming design behind it (the Summer Experiences category's picture expansion is well-concieved), but it doesn't have much meat to it yet.”
“Have to agree with you here. The home page changes at least once a week, and I love seeing all the recent news in the science world. I don't think I'd ever hear about some of these things without it. The weekly polls are really neat too because they let us see what other people like us think about some interesting topics. I have to say though... there are some really great activities when I have the rare time to do them.”
Thanks for all your opinions! And if you have not taken the poll and left your mark on the Discussion Board, why not join in the fun? Each week, you’ll find a new Poll available on Tuesday afternoon. Have an idea for a Poll? Check for the special “Poll Ideas” dropbox (they’re linked from the Connect page) and drop in your idea.
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