Last week we heard about the commercial spacecraft being readied to take Americans into low earth orbit and the International Space Station. (Note: SpaceX will make an attempt to launch it's Dragon spacecraft on May 7.) Last night, we heard from the NASA side of the house, where an new spacecraft is getting ready to explore beyond earth orbit.
The Orion spacecraft, now dubbed the Multi-Purpose Crew Vehicle (MPCV) is a robust capsule built along the lines of the Apollo spacecraft that will carry astronauts to the Moon, Mars, the asteroids and beyond. The spacecraft is currently undergoing testing as NASA develops new construction methods, like stir welding, to piece it together.
Barbara Zelon, Program Manager for Orion Outreach from Johnson Space Center, Texas, took 32 INSPIRE students through a virtual tour of the Orion spacecraft. She told of the design elements that will make it perfect for deep space exploration and the way we are testing it. First flight with a crew will take place sometime between 2018 and 2021.
Your chance to watch this chat come in the LiveChat archive. Stay on to the very end to find the passcode for the quiz, where you can earn 25 points! And sign up now on the Discussion Board for next week's chat where we will learn What's Next in human spaceflight!
April 17th of 2012, apart from being the day to return taxes, was a day that we will never forget. It was the moment when Discovery took its final flight but not to space, to the skies. This was done on top a modified Boeing 747. Let’s bring that momentous day back and talk a bit about our trip to see it. Since I live in Puerto Rico, this was an unforgettable opportunity that I will always cherish and want all of you to experience it through this blog.
We arrived at Florida on very early on April 13th. During the time we spent there before the flight my dad and I went to my future University, visited my sister and saw many places in Florida including obviously NASA. In the end, we traveled almost 900 miles of unforgettable experiences in only 5 days. Seeing people from my past internship and getting to meet new ones.
Our planned departure back to the island was on the 17th, the same day of the flight. We left our hotel at 3:30am in the morning and it took us about 1:30hours to get to the Kennedy Space Center Visitor Complex. Discovery, its ride and escort will take off at 7:00am. So we went early to get a nice spot. An interesting thing about this is that a few days ago we weren’t even planning on being on the state nor going to the takeoff.
We arrived at the Complex at 5:00am looking forward to seeing it. The trip was spectacular, there was fog on the road, little to no traffic and once we got there an amazing unforgettable moon. Big and yellowish just illuminating the area for what was about to happen. Not only this but the most memorable moment of it all was seeing this to the sound of the song made by Elton John called Rocket Man. I didn’t put it on a CD or iPod, it just came up on the radio as we were arriving just as if the rocket man era was saying goodbye for some time. Symbolizing the ending of three decades of Spaceflight. Hearing the song seeing the view of the pads, moon, stars, complex and lights was a very emotional moment.
When we arrived, people where already arriving and we parked ourselves in a strategic place and settle for the waiting time. Soon we saw the NASA buses, but not the one for the guest but the NASA employees. A spectacular flashback passed through my mind because it all looked like the same day I went with the other interns and employees to see Space Shuttle Atlantis land one last time on STS-135.
Later on I took my phone and settled it on the dashboard to see NASA TV while me and my dad waited. They were giving great reviews of the mating process of Discovery and the SCA videos that I didn’t have the chance to see earlier. Soon enough, we were getting closer and closer to takeoff and through the same speakers on the Visitor Complex that took guest through the process of the NASA missions, audio was coming out from Discovery and its past missions - another emotional moment.
Then as soon as the sun came out the SCA, Discovery and its escort spread their wings and took off. It did a series of impressive flybys and it was just spectacular seeing all of those great engineering marvels flying and waving goodbye to the people who were there to be part of history. The group of aircraft included a T-38, NASA helicopter and another NASA jet. It went from the Shuttle landing facility, to the VAB, the NASA industrial area, Cape Canaveral, Beaches, Patrick Air Force Base, over the Visitor Complex and one last past at the landing complex then later flying of into the sunrise to Washington DC were it gave another spectacular series of flybys. For me all of them were great we got chance to basically see all of the process of it going back and forth either through my phone or with our eyes in the sky.
If I had to choose one it would be when it came over the visitor complex, just going at a mere 300 feet a top us and seeing that dear shuttle, the carrier and its escort going through the rocket garden. That moment will always be remembered in my mind and the pictures that were taken.
Just about half an hour after takeoff we all bid her farewell and a safe trip to her new home were she will be treated well for her success that will be remembered by all mankind. Even though this will soon be done again with Endeavor, every vehicle will carry a different memory that NASA employees and us will always take with us.
I really hope that this has been of great help for you in picturing my experience and I wish you the best in seeing Endeavor takeoff and seeing later on the shuttle in their final monuments in the museums and places around the states. Remember that as the Shuttle fleet says goodbye a new era of Spaceflight will soon begin an era where we will take part of and once again not make the sky our limit, instead it will be space and the entire unknown that it covers and will soon be DISCOVERED.
By Jim Gerard, INSPIRE Education Specialist, KSC, FL
The space shuttle is retired to museums and America is left without a way to place astronauts in space. Is NASA over? The welcome answer is no! Thanks to the Commercial Crew Program, America has a bright future ahead.
The Commercial Crew Program provides a NASA partnership to private industry to produce launch services that could be used by both government and commercial entities.
Last night, Kennedy Space Center engineer Brittani Sims talked to 37 OLC members about her work with the Commercial Crew Program. Students asked questions related to safety, costs, and timelines.
Four corporations, Blue Origin, Boeing, Sierra Nevada, and SpaceX, have funded agreements with NASA to develop and build a spacecraft capable of taking four astronauts to the International Space Station. Three other corporations, ATK, Excaliber Almaz, and United Launch Alliance, are in an unfunded agreement to develop spacecraft and boosters. That is seven independent groups that will be looking for future engineers, scientists, and astronauts to build and fly spacecraft.
You can hear the entire presentation by navigating to the LiveChat archives and look for the "Commercial Space" LiveChat. Then, don't forget to take the associated quiz to earn your 25 points! And, you can sign up now for next week, when we will hear about NASA's entry in the next vehicle sweepstakes, the Orion spacecraft! See you then!
The sky is not the limit for producing artistic compositions. Put a camera on a tripod, point at a dark starry sky, and hold the shutter open for about 10 minutes, and the image will show stars as circular arcs. Normally, these star trails are created as the Earth rotates on its axis, with the center being close to either Polaris, the north star, or the Southern Cross, depending on which hemisphere you are in.
I got the idea to do the same thing from Space Station; however, the physics of orbit adds a special twist. As Space Station orbits, it keeps one side always facing the Earth (the nadir direction from our point of view). This requires the Station to complete one revolution about its axis each orbit, just like the Moon. ISS rotates about its center of mass, which happens to be in the Unity, or Node 1 module. So it rotates almost aligned with the Station’s long, backbone-like truss.
Space Station makes one revolution every 90 minutes (the Moon takes 28 days). As a result, long-exposure pictures taken from the Station show star trails as circular arcs, with the center of rotation being the poles of Space Station (perpendicular to our orbital plane). Space Station is inclined 51.6° from Earth’s equator, so the “poles” are now at 38.4°.
My star trail images are made by taking a time exposure of about 10 to 15 minutes. However, with modern digital cameras, 30 seconds is about the longest exposure possible, due to electronic detector noise effectively snowing out the image. To achieve the longer exposures I do what many amateur astronomers do. I take multiple 30-second exposures, then “stack” them using imaging software, thus producing the longer exposure.
Due to our altitude, it is possible to see both the north and south axis of our orbit at the same time. This makes possible star trail images with two circles defined by arcs with opposite inflections. This geometry is hard to arrange from only one window so I use a fisheye lens, one with a full 180° image circle, to make this composition.
In addition to the star trails, many other phenomena of nature can be seen. But I’ll save that topic for another post.
The INSPIRE program can be a gateway to new opportunities through NASA. During the summer of 2011, I worked with Dr. Scott Mest of Goddard Space Flight Center on a project of mapping areas of the Moon to determine the areas of the greatest scientific value for a future mission to investigate. This project gave me my first experience of work at NASA and my first interactions with NASA scientists, and would later serve as an opportunity to experience first-hand a major conference of space scientists and engineers.
In December, 2011, I received an e-mail from Dr. Mest in which he presented me a once-in-a-lifetime opportunity. His work on the results from the Dawn mission to Vesta left him with too many papers to present alone, and so he offered me the chance to present my work on mapping lunar regions of interest at the Lunar and Planetary Science Conference in Houston, Texas! I immediately accepted his offer, and began working on the poster on which I would present my results.
After clearing my absence from school with the relevant officials, and printing out my poster, I got on the plane to Houston and arrived on Wednesday, March 21, 2012.
My first day was spent putting up my poster and examining the displays that the other presenters had here. Taking place at the same time and in the same building as the Lunar and Planetary Science Conference (LPSC) was the Nuclear and Emerging Technologies for Space (NETS) Conference. Engineers representing Pratt & Whitney, Lockheed-Martin, and various other corporations and many NASA centers were present here to discuss the role of nuclear power in space exploration, from the past and present use of Radioisotope Thermoelectric Generators (RTGs) on space probes and during the Apollo program to the future use of very powerful nuclear reactors to propell crewed and scientific missions faster and farther than ever before!
I learned about new maps NASA scientists are producing of the dwarf planet Vesta, an entire new world not mapped in detail until the Dawn probe entered orbit just a few months ago. Here scientists see in craters millions of years old geological processes that reveal this world's dynamic evolution. I also met with veterans of the Desert RATS tests and the Mars Desert Research Station, who explained to me how their work is paving the way for future manned exploration of the asteroids and Mars by developing techniques for communicating effectively with Mission Control and planning a traverse of a region of scientific interest. I also learned about how scientists analyzing the Martian polar ice caps are using Greenland as a terrestrial analogue to form a hypothesis about how the ice beneath the polar ice cap's surface might look on Mars.
From the engineers of the NETS conference, I learned about topics in nuclear engineering ranging from the Stirling-cycle electricity generators to be used on future missions using radioisotopes, such as the Titan Mare Explorer, to Nuclear Thermal Rocketry, which uses a nuclear reactor to directly heat a working fluid to make thrust and electric power, to the development of nuclear fusion as a spacecraft propulsion mechanism in the farther future. I got to meet many engineers, including the world-famous Dr. Stanley Borowski, the lead nuclear thermal rocket engineer at Glenn Research Center.
My own presentation, given on Thursday night, focused on the work I did as part of the INSPIRE Summer STEM Experience in 2011. I talked about how my work on maps of the Copernicus Crater and Apollo 15 Regions of Interest helped identify areas of scientific interest there, like extinct volcanoes near the Apollo 15 landing site to the enormous central peak of Copernicus Crater.
I wouldn't have been able to attend this conference without the help of Dr. Mest and the NASA INSPIRE Program. Through the INSPIRE Program and thanks to Dr. Mest, I got to broaden my horizons and learn a lot about planetary science and engineering from the men and women who work on them first hand.
By Megan Rosenberg, INSPIRE OLC Member, 11th Grade
How can I make a difference? I started three years ago with a passion to make a difference through environmental research and it has brought me to the title of Miss Teen Earth Pennsylvania and an invitation to the White House Environmental Education Summit.
In 2004, when I was just 9 years old, my house was flooded by the tenth most intense Atlantic hurricane ever recorded. I took the ten steps into my basement with my father and sooner than I realized my family lost so many memories in the soaking boxes. Five years later in 2009, I was invited with my engineering group to present our national “Future City” at the local Pittsburgh Water Authority. There I learned about a rain barrel! When I first heard about a rain barrel and the benefits such as reducing flooding, I became so passionate about bringing awareness to homes with out this device. I continue to think that if we had a rain barrel then, I didn’t have to lose my first science project or building blocks.
It can change lives! I soon became curious if there was any way to additionally enhance the rain barrel to help the environment. In two years of research and multiple engineering designs, I successfully added a hydroelectric generator to my rain barrel that I installed in my backyard, and I started sharing my idea with the world. I contacted Create Change Africa to learn about their water crisis relief efforts in Ghana and how rain barrels impact developing countries with a limited supply of drinking water. In the past three years, I have worked with this community in Africa to help others become more aware of their water crisis and their environment.
Last month, I was crowned Miss Teen Earth Pennsylvania 2012. I am very honored to receive this title and be recognized for my efforts to keep our planet more environmentally friendly. I am the 2011 awardee of the President’s Environment Protection Agency Youth Award for my state and six state region.
Miss Teen Earth is a beauty pageant that carries the message of environmental activism of confident young women to the rest of the world. The words “Beauties for a Cause” describe these young women, like myself, as role models who preserve the beauty and integrity of our own lives while we continue to inspire and encourage new generations to protect the living world and all its creatures. My platform, Green4Good, encourages everyone to conscienciously help our environment. Through my activism, I am aiming to encourage others to become eco-friendly and “green for good!” As an environmental advocate, my goal is to bring awareness throughout my community, my state, and our nation about the importance of taking care of our planet, Mother Earth. I will be representing Pennsylvania at the national Miss Teen Earth United States Pageant in August 2012 in Long Beach, California.
Unfortunately, there are many misconceptions about “going green” and proposed “green initiatives”, as the biggest misunderstanding is that the movement to help our planet is too expensive. Contrary to this belief, I am spreading my platform’s message that going green is simple, and everyone can help. Did you know? Recycling one ton of paper saves 20 trees, 7,000 gallons of water, three cubic yards of landfill space, 60 pounds of air pollutants, and saves enough energy to power the average home for six months.
My title has given me the opportunity to spread the message of environmental awareness with so many individuals more than I ever thought I could reach. I had the opportunity to be an honored “green” guest at the Pittsburgh’s Saint Patrick’s Day Parade where I got to share my message with everyone from Congressmen to kids. I waved to Vice President Joe Biden and U.S. Ambassador to Ireland and Steelers chairman emeritus Dan Rooney. And keep an eye out for me this weekend marching with the USA Science and Engineering Festival contingent and Grand Marshal Buzz Aldrin in the 2012 Cherry Blossom Parade Festival! It will be an out-of-this-world experience! On Monday, April 16, I was invited by President Obama to attend the White House Environmental Education Summit.
You CAN make a difference on the environment! For more ways to help and to follow my journey visit: http://www.facebook.com/missteenearthpennsylvania2012.
I have been a part of the NASA INSPIRE program for the past three years and a Huntsville, Alabama Space Camp Academy Alumna. It is because of the NASA INSPIRE program that I have a sincere appreciation for science and technology. THANK YOU INSPIRE!
By Jim Gerard, INSPIRE Education Specialist, KSC, FL
On the 31st anniversary of the first launch of the Space Shuttle, 44 INSPIRE OLC members gathered to hear my presentation on the History of the Space Shuttle. My goal was to show students some of the engineering design process that went on in the 70's and 80's that led to the vehicle we have today. My hope is that they saw some parallels between that time and where we are today waiting for the next vehicle that will launch Americans to space.
I also talked about the retirement of the orbiters and where they will eventually be placed on display. Kennedy Space Center right now is gearing up for the immanent departure of Discovery, which will fly up the east coast on the back of the 747 Shuttle Carrier Aircraft (find out more of the orbiter's arrival in Washington DC here: ow.ly/acok3). How close will you be to one of these historical craft, or the astronaut trainers that will also find their way to museums?
Before each LiveChat we are opening the floor to encourage students to opine about a Pre-chat Topic Question. Our question for last night was "Did we retire the Orbiters to early?" We had a lively discussion with most students think we should have had a new vehicle in place before setting aside the old one. Try to log in early and be part of the fun!
Next week, Brittani Sims from the Commercial Crew office here at KSC will talk about the different vehicles competing to be the next American orbiter. Find out what the future holds by signing up now for the LiveChat on April 19 at 8pm CT!
Gold, silk, and spices were tangible treasures from past exploration. The Conquistadors were particularly good at extracting gold from the local inhabitants. Sir Francis Drake, before he acquired the title of “Sir,” brought back enough treasure from his circumnavigation of the globe to provide more than half the income for the British crown for an entire year. The frontiers of space likewise offer treasures won from exploration, treasures that will enrich our lives and enhance our standard of living. These treasures are golden but not gold. They contain secrets about the biochemistry of life, and will allow us to increase our understanding of how life functions. No more silver and gold; from Space Station we have blood, spit, and urine, treasures that contain secrets more valuable than a chest filled with pillaged Aztec gold.
On Space Station, we are human guinea pigs for a wide variety of medical experiments. The weightlessness of space offers a biochemical challenge to our bodies, which develop a host of fascinating maladies such as bone decalcification, cataracts, retina swelling, eye focus shifts, smooth muscle atrophy, fluid imbalance, gross weight loss, cardiovascular degeneration, and more. In spite of these maladies, humans can thrive in space, proving that as a species, we are a hardy lot and can explore places where we were never meant to go.
The microgravity of Space Station allows for yet one more experimental variable, offering an amazing and unique environment in which to study human physiology. Mother Earth throughout time has tormented creatures with every possible variation of environmental parameters. She has tweaked temperatures from hot to cold, pressures from high to low, chemical compositions from reducing to oxidizing and acid to base, and more. She has thrown stones at us from space and spewed out molten rock and ash from within. The layers of rocks are littered with fossils of hapless creatures that could not make the grade, or, through no fault of their own, were simply caught in the wrong epoch of geologic time. The history of life on Earth is the story of species extinction, a fascinating thought for those of us that are still here and can contemplate such a construct.
With all this change, with all this process, throughout all the evolution, the one factor that has been constant for billions of years is the magnitude of Earth's gravity. Now we can venture off the planet and for the first time in the history of life, vary the influence of gravity by a factor of one million. The fact that we can survive in space is in itself an amazing discovery. We truly are off in a new frontier, one that life has never seen on Earth, and it is on this frontier that physiological secrets can be pried from the people who go there.
As the crew of Space Station, we routinely puncture veins, drool on cotton swabs, and urinate in bags. These samples are processed in centrifuges, sprinkled with preservatives, placed in tubes, and stored in MELFI, better known as “the freezer.” Kept at -98° C, these samples are stored for months before return passage to Earth can be arranged. To ensure safe passage of these treasures through the ride back to Earth, NASA has developed a special cold box that keeps them frozen for several days, ensuring unthawed recovery by ground crews, happy life science researchers, and crew members relieved to know that their bloodletting was not in vain.
The cold boxes themselves are an engineering marvel. They are nearly equal in thermal conductivity to a vacuum dewar (Thermos bottle) with only a fraction of the mass. They are made from truly space-aged materials; aerogel and Mylar. Aerogel is the most gossamer solid material known. Appearing more like solid smoke, aerogel has a density only 10 times greater than that of air (steel has a density 7,000 times greater than air) making it one of the best thermal insulators known, bested only by vacuum. Aerogel is brittle, readily crumbing into dust. To prevent this eventuality, it is placed inside a skin of Mylar (plastic) film. The air is then sucked out, making this structure as rigid as a vacuum-packed bag of coffee (which feels brick-hard until the package is opened). These Mylar-packed aerogel structures can be made into odd shapes, enabling cold boxes to fit in unused pie-shaped spacecraft volumes.
When new technology is developed, other unintended uses often surface. Such was the case for the cold box. Developed for space, it ended up in Antarctica, not for keeping things cold but for keeping them warm. In 2006-2007, I had the good fortune to live in a tent about 200 miles from the South Pole during a scientific expedition to Antarctica as part of a meteorite gathering team called ANSMET (Antarctic Search for Meteorites). The conditions found in Antarctica preserve and concentrate meteorites, a discovery not realized until the early 1970’s. They accumulate on the surface of the blue glacier ice, and because they appear as strongly contrasting black specks from a distance, they can be recognized from afar and gathered like cosmic Easter eggs. For the last 30 years, annual expeditions working during the short Antarctic summers have gathered over 20,000 meteorites. During our six-week stay, we advanced this number by 850.
Living in a tent under primitive conditions, the ambient temperature danced around -20° C throughout the continuous daylight of the Antarctic summer day. Including wind chill, the effective temperature was -40° C. At such temperature levels, it does not matter what scale is used. In our tents, the floor temperature stayed at -20° C and the chimney varied from -20° C to +20° C, depending on whether the stove was lit. Any water-based substance became a frozen lump. Most electronic devices refuse to operate under these conditions; from batteries that do not make sparks (lithium-ion batteries do not like to be charged if less than 0° C), LCD displays that give only blank stares, or hard drives that do not turn at the right speed.
The Antarctic hot box in its former life was an engineering test article used to make thermal measurements for the design of the spaceflight units. Having served that purpose, I found it in a dank NASA cabinet, itself in cold storage and seemingly of no further use. Brought out from retirement, this high-tech space cooler found itself strapped to a Nansen sledge, pounding through the Antarctic interior over snow structures known as sastrugi. In a sea of cold, it offered a small oasis of warmth. We also kept our Tabasco sauce and sourdough starter in the hot box, demonstrating the value of having small comforts when living on the frontier.
Thus we behold the new treasure garnered from the frontier of space. Not gold or spices, but knowledge. Knowledge always has value, even if we don’t immediately know or recognize it. The real treasure of new exploration is the larger knowledge base and the expanded imagination we develop from it. In time, all knowledge shows itself to be useful in some way. The fact that today it is difficult to pinpoint the value of space exploration shows that it is truly venturing into terra incognita, unknown territory.
Tierra del Fuego, the land of fire, was what Magellan named the tip of South America in 1520. He saw the fires set by local inhabitants who did not want the Portuguese explorer to set foot on their land.
A new page in the history of this distant part of our globe is now being written. Oil has been discovered off the eastern shore of Tierra del Fuego, and Argentina is building offshore platforms to access it. Brightly lit, they appear from orbit as constellations—not in the starry sky, but on the surface of the sea. Collectively, they are one of the most brightly-lit areas I have seen anywhere on Earth (except for Las Vegas, which still holds the title). From my orbital perspective, this is no longer Tierra del Fuego but Mar del Fuego.
In these pictures taken from Space Station, the dim lights from Tierra del Fuego, visible in the background, do not hold a candle to the bright lights of the offshore oil platforms.
A couple of articles back, I asked the following question:
"The whole orange-flame thing is not something I entirely understand...Any ideas from anyone else?"
I was talking about the flame stack during a night test at the NASA Stennis Space Center. It was a legitimate question. Combustion chemistry is really not my specialty. Lots of things are not my specialty. Try as I might, I've found that I can’t know everything about everything. Indeed, considering the many brilliant and knowledgeable people with whom I have the privilege of working here at NASA, I've come to accept the conclusion that there is a lot more stuff to know than can ever be learned. But that can never stop you from learning something new. And so I have with this.
In response to my blog question, we received a number of comments on the blog and those are posted. Thank you for your inputs and interest.
However, behind the scenes (so to speak), a coworker of mine, Robin Osborne, who does have experience with this kind of stuff read the blog and starting poking around amongst her notes and amongst her fellow experts in the field of flame spectroscopy. Below is a picture taken of igniter testing at MSFC using a gaseous hydrogen-oxygen mixture. Here too you can see a red-orange flame although it takes a distance for that colored portion to show itself.
According to Dr. Robert Pitz from Vanderbilt University, "Pure hydrogen (with no sodium) -- air flames will glow red in a dark room due to the water vapor emission lines." Both Dr. Joseph Wehrmeyer working in support of the Air Force and Richard Eskridge from NASA concur, noting that water vapor generates an orange-red-infrared continuum in such flames. However, all of these individuals also noted that there is a strong orange coloration in such flames due to sodium contamination within the hydrogen. The sodium is present as sodium hydride within the liquid hydrogen which decomposes at high temperatures to generate the vibrant color. The sodium contamination is a byproduct of how large, industrial quantities of hydrogen are made for uses such as, for example, flying the Space Shuttle. Dr. Christopher Dobbin of NASA noted that in the 1990 timeframe he was engaged in an analysis of the flame plumes ejecting from the Space Shuttle Main Engines (SSME). He said, "The (time) average sodium concentration we measured in the SSME exit plane was 0.091 parts per billion." That doesn’t sound like much, and it's not enough to impact engine performance or operation, but it's still enough to measure based upon spectral analysis of the plume. Another possible contaminant, according to Richard Eskridge, is potassium and that can further contribute red emissions.
So, there you go. It's a matter of water vapor at the right temperature and pressure (and therefore density) and a couple of key contaminants in the fuel. It's "common knowledge" around here amongst us Datadogs that the plume of a Lox/Hydrogen rocket engine is clear. But that's not entirely correct. It's nearly clear. It still has the characteristic red-orange tint, but it's at a density where the emission is too low to see. On the other hand, for the flame stacks at the test facility -- the origin of this whole discussion -- we're talking combustion at atmospheric pressure so the water vapor products are denser as are the relative contamination levels since it's a fuel-rich environment. And that's why they show up at those brilliant colors in the nighttime pictures.
See, even old Datadogs can learn new tricks. Thank you to everyone who added their two cents, but especially to Robin Osborne for her inputs and insight.
NASA's Space Shuttle program was one of the greatest achievements of the Space Age. From 1981 to 2011, the Space Shuttles, Columbia, Discovery, Challenger, Endeavor, and Atlantis, flew astronauts to and from Space on various missions.
The history of the Space Shuttle goes all the way back to the Mercury Program, from 1962-1963. Mercury launched six people into Space, and laid the foundation for people to eventually live in Space.
After Mercury came Gemini, from 1965 to 1966. There were ten launches with the Gemini Program, and the basis here was for people to learn to work in Space.
After the Gemini Program came the famous Apollo Program, 1969-1972. The purpose of the Apollo Program was to explore Space. It was with Apollo that America made the historic milestone of landing a human on the moon, with the Apollo 11 spacecraft in 1969.
After Apollo, NASA wanted humans to go to Mars. To do this, we needed to build a moon base first, and for the moon base, we needed a low Earth orbiting space station. This leads us to the Space Shuttle. In 1972, Congress approved the budget for the Space Shuttle Program. When the Apollo 16 astronauts were informed of this approval, while still on the moon, they jumped up three feet in excitement!
Now that the funding was secured, NASA turned to Max Faget for assistance in designing the Shuttle. Max Faget designed both the Mercury and Gemini spacecraft, and assisted in the design of the Apollo spacecraft, so he was a logical choice for the design of the Space Shuttle. His early designs were conical, like the Apollo, with extra boosters and engines for returning to Earth. The design that NASA wanted to use had a plane like structure, much like today's Space Shuttle, but what was unique about it was the booster rockets. The rockets were also designed like a plane, with wings, a cockpit and jet engines; this was so that a pilot could sit in the cockpit and fly the rockets back to Kennedy Space Center for reuse. NASA was all set to go with this design, but than the early plans showed that the approximate weight at launch would be 4,600,000 lbs! So they redesigned the rockets to be expendable, and fall off at a certain point to decrease the launch weight.
Once they had this part of the plans down, NASA turned to Boeing, Grummen and Thiokel to design the actual shuttle part. The main specification was that the payload had to be 60 ft. long and 15 ft. wide to allow for military cargo.
Grummen opted to put extra rockets on the Shuttle and launch that as it was.
Boeing came up with putting wings and a cockpit on the Saturn 5 rocket, and their design was closest to what we have today.
Thiokel decided to put rocket boosters along the sides and under the main shuttle.
NASA eventually decided to use the Saturn 5 rocket, with boosters along the sides of the Shuttle.
Now they needed fuel. There are two types of rocket fuel, solid and liquid. The benefits to solid rocket fuel are that it is cheaper, easier to use, and less complex than liquid fuel. But liquid fuel, although more expensive, harder to use because it needs better containers, and more complex, is actually safer. This is because, while liquid fuel can be shut off in the case of an emergency, solid fuel can not.
So NASA's final design was the Shuttle, with an external fuel tank below, and boosters along the sides, just like we have today. :)
Enterprise was the first Space Shuttle. Originally called 'Constellation'; so many Trekkies wrote to NASA that they finally gave in and named it 'Enterprise'. Enterprise was designed to go into Space, but all it was ever used for was testing launch and landing sites.
Next came Columbia. Columbia was the first Space Shuttle to launch all the way into space and come back down in 1981. It exploded during a launch in 2003.
Challenger made very few flights before it exploded in the atmosphere after launch in 1989.
Discovery made more flights than any other shuttle. It launched the Hubble Space Telescope in 1991, and was the 'Back to Orbit' vehicle after both the Challenger and Columbia Tragedies.
Endeavor made more flights than any other shuttle except Discovery, and still has one more flight to go before retirement.
Atlantis was the last shuttle to be launched, this happened in Summer 2011.
And Discovery, Atlantis and Endeavor all helped to build the International Space Station, the first permanent space station and first step towards the moon base and Mars.
The Space Shuttle was originally to be replaced by the Constellation Program, but sadly, the funding had to be cut. However, NASA will continue flying to the Space Station using the new Orion spacecraft, and hopes to build a permanent moon base using Orion.
Put a little kid into the driver's seat of a (safely parked) car and what's the first thing that they do? They grab the steering wheel and twist it back and forth. Twisting the steering wheel back and forth is just about the most intuitive, intrinsic -- practically instinctive -- sense of "driving" that I can imagine. Even the handlebars of a bicycle or a motorcycle fit into the same idea. Can you think of driving a car or a boat or, well, anything, without a steering wheel (of some sort)? It's tough, isn't it?
Okay, now think of a launch vehicle blasting off the pad and upwards heading towards the sky. Other than for some extreme, emergency conditions, there is not anything that stands in for the steering wheel on a launch vehicle during ascent. The process of steering the vehicle requires such precision and responsiveness that it has to be automated. Sorry Buck Rogers, the computer is flying the vehicle. But, even without a steering wheel, per se, how does steering happen?
With a car, you point the front wheels and, thanks to friction between the tires and the road, you get pulled (or pushed for the sports car purist and NASCAR fans) in that direction.
With a boat, you use a rudder so that the water pushing against it points the boat in the direction you want to head.
With an airplane, you have to use a combination of aerodynamic surfaces since you're now dealing with steering in three dimensions, not just two as with an automobile or a boat. But the idea is basically the same: the air through which you're moving pushes against the aerodynamic surfaces and points the plane in the direction you need to go.
What do you do with a launch vehicle? Not long after the first couple minutes of flight, you're so high in the atmosphere that there's not enough air to effectively use aerodynamic surfaces. In other words, you don't have a road and a rudder won't work. So what do you use when you don’t have anything against which to push? That's right: a rocket!
You could, if you chose to do it this way, use dedicated steering rockets. We do use these when we're in space and we typically call them "retrorockets" or "reaction and control" rockets. But during the ascent, you already have a big rocket engine pushing you along so you might as well use that if you can, but to do so, you need to twist it around…
[Yes, I can’t help myself. I had to make a musical reference. "Twist and Shout" (written by Phil Medley and Bert Russell) was originally recorded by the Top Notes, then the Isley Brothers, and, eventually by the Beatles (as so memorably replayed many years later in "Ferris Bueller's Day Off"). Lots and lots of people have done versions of this song, but probably the most bizarre was Mae West -- yes, THAT Mae West -- when she was 72 years old. Who knew?]
What do I mean with regards to twisting a rocket engine? Here's a video of what we call "gimballing" an engine on the test stand, in this case a Space Shuttle Main Engine (video provided by my friend and coworker Rick Ballard from his Liquid Rocket Engine class materials):
So, for a launch vehicle during ascent, you accomplish steering by pointing the thing pushing you, i.e., your main propulsion rocket engine. That's a cool video, huh? But how do we accomplish that? The movement itself is provided by hydraulic actuators. These are push/pull devices driven by fluid pressure. The brakes on your car are hydraulically actuated, for example. Another example of hydraulic actuators are those lifts at the garage they use to pick your car up off the ground. In other words, they can be very powerful devices. You can do a quick web search on "hydraulic actuators" and find all kinds of pictures and articles and even sales pitches from manufacturers.
On the rocket engine we put just two connection points for the actuators at ninety degrees apart from each other. This gives us what you can think of as full, two-dimensional coverage. If you remember back to math class, everything on a flat page can be located via X-Y coordinates. Thus, one actuator provides the X-direction and the other provides the Y-direction. And, with that, we can point the engine to any location within a given, limited range of movement.
At the top of the engine, in order to allow the movement, we put in what amounts to a universal joint. It's called the "gimbal bearing" and it's like the ball-and-socket joint in your shoulder except that this joint has to carry the full thrust load of the engine while maintaining its flexibility. Because of the conditions seen by the engine, you can't use any typical lubrication like grease or anything like that. Instead, we use a Teflon-impregnated fabric layer.
I like the picture above showing several guys working with typical engine gimbal bearings. In the picture you can get a sense of how beefy these things are when assembled and you can clearly see the "ball" part of the ball-and-socket joint.
Have we gotten to the really, really neato part yet? Yes, we have (in my humble opinion). Here it comes. How is it that we can move around the engine? I mean, besides the big ball-and-socket joint at the top that is meant to move around, all the rest of it is assembled out of all kinds of stiff metal pieces, right? It’s not like you can stick cryogenic propellants through a flexible rubber garden hose. So how do we get the compliance in the rest of the engine components that allow for the movement the actuators and gimbal bearing are providing? With no compliance, the actuators would push and pull, and, assuming that they were powerful enough to do damage (and they usually are), the engine ducts would buckle and crush and, frankly, you'd have a crumpled mess. What we do then is build the compliance into the engine with specific parts to provide this functionality. This is accomplished in different ways on different engines. Below is how this compliance is accomplished for J-2X for the main propellant lines:
That pretty piece of hardware is a propellant inlet duct. In fact, that picture is of the first new propellant inlet duct fabricated for a J-2, J-2S, or J-2X engine in forty years. This new duct is like the heritage design but better, safer, more robust. It is an extremely difficult piece of hardware to make in that it involves some very highly specialized welding techniques. So a big shout-out goes to Pratt & Whitney Rocketdyne and the guys on the shop floor. Way to go guys!
How does it work? The sections with the convolutions are called bellows. Above is a cut-away of a metal bellows made by the same company as our propellant inlet duct, Gardner Bellows Corporation, but not our same design. The bellows take advantage of the way that metal can act like a spring. If it doesn't get bent too far, the metal will bounce back undamaged. These dozens of convolutions in the bellows allow for enough movement that the whole thing acts like a stiff spring. The hinged structures on the sides hold the bellows together and constrain the springy parts and make sure that they stay in their groove (so to speak).
The next natural question about this duct is this: Why does it appear to be in two pieces, an upper bellows and a lower bellows? The answer is that it isn't in two pieces; it's in three pieces. In between the upper bellows and the lower bellows is a third set of bellows that you can't see very well and that's because they're really flat. This is the torsional bellows and it provides for a slight twist between the upper and lower sections. When you're gimballing the engine, not only do you need these ducts to bend, you also need a bit of twist…
I think that the torsional bellows is even cooler than the bending bellows. Have you ever tried to twist a long piece of wood, like maybe an eight-foot-long, one-by-two strip? The longer the piece, the easier it is to get a few degrees of twist. A short piece of wood, even with the same cross-sectional dimensions, won't allow for as much twist. There is an "allowable twist per unit length" thing going on: longer = more twist, shorter=less twist. Okay, now assume that the same is true for a metal pipe. If you have a very long metal pipe and you apply a twisting force to it (torsion), you can get some movement, more movement than you’d get with a short pipe. But there's no space on a rocket engine for a very long pipe, so how do you allow for some twist? What we do is collapse the long pipe into shortness by making it into a very tight accordion-like package. In other words, we add convolutions kind of like the bending bellows, but make them very tight, very flat. So, all of the metal "length" is still there, just in a really compact, squashed package. It kind of feels like cheating, somehow, but it works. See?! That's just neato!
In addition to the big ducts, the propellant ducts, you also have to take into account any other connections between the engine and the vehicle stage. If you think back to the article about vehicle integration, you'll remember that we've got pneumatic lines and propellant pressurization lines and helium spin start lines connecting the engine to the stage. In all of these lines we have to make provisions for compliance to engine gimballing motion. As you can imagine, this makes the design for these pieces not simple. But nobody ever said that rocket engines were supposed to be simple. Also note that different rocket engines use different approaches for achieving the compliance necessary to accommodate gimballing, but they almost always use "springy" metal bellows in some sort of configuration.
The first J-2X engine that will see gimballing in the test stand will be development engine E10002. That should be happening later this year. Stay tuned. I’ll certainly be posting some gee-whiz video after that happens. Go J-2X!
