NASA engineers conduct a successful test firing of RS-25 rocket engine No. 2059 on the A-1 Test Stand at NASA’s Stennis Space Center in Bay St. Louis, Mississippi. The hot fire marks the first test of an RS-25 flight engine for NASA’s new Space Launch System vehicle. Credits: NASA/SSC
NASA engineers conduct a successful test firing of RS-25 rocket engine No. 2059 on the A-1 Test Stand at NASA’s Stennis Space Center in Bay St. Louis, Mississippi. The hot fire marks the first test of an RS-25 flight engine for NASA’s new Space Launch System vehicle. Credits: NASA/SSC
NASA engineers have successfully test fired the first flight engine destined to power the agency’s mammoth new SLS rocket that will launch American astronauts back to the Moon and deep space for the first time in nearly five decades.
A sample of the detailed drawings of Stanley VonMedvey that explain how spacecraft work. Credit and copyright: Stanley VonMedvey. Used by permission.
Freelance animator and storyboard artist Stanley VonMedvey has started using his remarkable talents to create short videos to explain a pretty complex topic: how spacecraft work. He’s made two so far and they are wonderfully concise, clear and easy to understand. Plus his hand-drawn animations are incredible.
Here’s the first one that caught my eye, about the space shuttle and the concept of reusability:
VonMedvey describes himself as “completely obsessed with and fascinated by space exploration,” and he wants to share what he’s learned over the years about spaceflight.
He’d like the opportunity and resources to make more videos, and has started a Patreon page to help in this process. Right now, he creates the videos on his own (using the time-honored home-recording technique of draping a blanket over his head) in his home officee.
“I’d like to make a lot more videos,” he writes on Patreon, “explaining things like Hohmman transfers and laser propulsion and the construction techniques of O’Neill cylinders. I want to make long form videos (2-3 minutes) that explain a general idea, and short form videos (30 seconds) that cover a single word, like “ballistics” or “reaction control”.
The second video he’s done covers expendable launch vehicles:
Enjoy these great videos and if you’d like to see more, consider supporting his work. See more of his drawings at his website.
The crew of Challenger, lost on January 28, 1986. Credit: NASA.
It was thirty years ago, January 28, 1986, that space shuttle Challenger exploded 73 seconds into its flight, killing seven astronauts. This is a tough time of year in the history of human spaceflight, as 19 years on January 27, 1967 three astronauts died in a fire in the module of Apollo 1. Then on February 1, 2003, space shuttle Columbia disintegrated as it reentered Earth’s atmosphere, killing all seven crew members.
Remembering these events brings home the fact that even today, spaceflight remains far from routine. But over the years, what else have we learned from these tragedies?
Christa McAuliffe. Credit: Challenger’s Lost Lessons
But Jerry was also featured in an article we did in 2008. A year earlier he came across a file of papers from 1985 that proposed how teacher Christa McAuliffe’s eight lessons would be performed on orbit as part of the Challenger mission. Woodfill worked to find old videos, photographs and other materials that had been tucked away in sadness and grief following the loss of Challenger and put together lesson plans and gave them to the Challenger Center. The lessons are available on the Center’s website.
Jerry and I discussed other “lessons” that may have been learned from the tragedies, and he had some interesting ideas about paradigm shifts that have occurred over the past 30-plus years. Here are a few “old” ideas that have changed or are in the process of changing:
Civilians, especially women should not be launched on risky missions to space
The 2013 astronaut candidate class. Front row, left to right: Jessica Meir, Christina Hammock, Andrew Morgan. Back row (left to right), Anne McClain, Nicole Mann, Tyler (Nick) Hague, Josh Cassada and Victor Glover. Credit: NASA
We’re certainly beyond the “women can’t do what men can” in our society (for the most part, anyway), and NASA’s last class of astronauts was 50% women (4 out of 8). It did take NASA until 1978 to hire the first female astronauts.
As far as civilians being part of space flight…. that’s the whole point the pioneers of spaceflight did what they did, to try and make flying to space as routine as flying in an airplane.
“While we’re not quite there yet,” said Woodfill, “the prospects for civilian space travel is altogether more plausible. “Now we have a maturing commercial space paradigm that wholly embraces the idea of everybody someday being eligible for a trip to space.”
Woodfill also mentioned that he used to hear that some people thought the idea that a Challenger-like mission should never be attempted again.
“That is refuted by the Challenger’s Lost Lessons project in 2008 and how much these recovered lessons mean to the families of the crew,” he said, “ and to the teachers that are now using these lessons in their classrooms.”
McAuliffe’s backup, Barbara Morgan completed her space shuttle flight in 2007 as a mission specialist, doing special education activities during the mission.
Nothing good can come of such a tragedy.
“An obvious challenge to such a posture was a redesigned, safer, more robust Solid Rocket Booster system,” Woodfill said. “In fact, it led to the work-horse SRBs adapted and upgraded for the Space Launch System (SLS) which will likely take us to Mars.”
The tragedies have provided lessons to be learned. “Go-fever” has been tempered with a more analytical view of each mission and the potential risks it entails. Crew safety at NASA has become top priority. All NASA workers are told to “speak up” if they see something that might compromise any mission.
Human spaceflight is too risky.
Dr. Robert H. Goddard (second from right) and his colleagues hold a liquid-propellant rocket in 1932 at their New Mexico workshop. Credit: NASA Goddard Space Flight Center
This debate will likely continue, but ask anyone associated with spaceflight and they’ll tell you they know the risks and that it’s all worth it for what it means for humanity. You can read Neil de Grasse Tyson’s ideas about this here.
National Geographic is currently running a show they produced called “Challenger Disaster: Lost Tapes,” that shows some old footage shot at NASA following the accident. Shown is then-Vice President George H.W. Bush and astronaut and Senator John Glenn who met with NASA’s space shuttle launch team at Kennedy Space Center in Florida. Bush said he met with the families of the lost astronauts and relayed that they pleaded that the space shuttle program continue “forward full speed.”
Glenn said, in part, “We’ve had tremendous triumph. …. And with this program, we’ve succeeded. Really, if we’re honest about it, beyond our wildest dreams. I would have never thought we’d go this far without losing some people, at something where you’re going at 5 miles a second, with the heat of reentry and the complexity of a system where everything has to go right. Now, we have a tragedy that goes along with our triumphs. I guess that’s the story of mankind.”
As many have said, the future doesn’t belong to the faint of heart, and it is part of human nature to explore and push the boundaries. But there are always lessons to be learned and ideas to be challenged. That’s part of the story of humankind, too.
The first RS-25 flight engine, No. 2059, is placed on the A-1 Test Stand at Stennis Space Center, Miss. The engines were built by Aerojet Rocketdyne and are being tested in 2015 and 2016 to certify them to fly on NASA’s new Space Launch System (SLS) rocket. SLS-1 will launch on its first uncrewed mission in 2018. Credit: NASA
NASA took another big step on the path to propel our astronauts back to deep space and ultimately on to Mars with the long awaited decision to formally restart production of the venerable RS-25 engine that will power the first stage of the agency’s mammoth Space Launch System (SLS) heavy lift rocket, currently under development.
Aerojet Rocketdyne was awarded a NASA contract to reopen the production lines for the RS-25 powerplant and develop and manufacture a certified engine for use in NASA’s SLS rocket. The contract spans from November 2015 through Sept. 30, 2024.
The SLS is the most powerful rocket the world has ever seen and will loft astronauts in the Orion capsule on missions back to the Moon by around 2021, to an asteroid around 2025 and then beyond on a ‘Journey to Mars’ in the 2030s – NASA’s overriding and agency wide goal. The first unmanned SLS test flight is slated for late 2018.
The core stage (first stage) of the SLS will initially be powered by four existing RS-25 engines, recycled and upgraded from the shuttle era, and a pair of five-segment solid rocket boosters that will generate a combined 8.4 million pounds of liftoff thrust, making it the world’s most powerful rocket ever.
The newly awarded RS-25 engine contract to Sacramento, California based Aerojet Rocketdyne is valued at 1.16 Billion and aims to “modernize the space shuttle heritage engine to make it more affordable and expendable for SLS,” NASA announced on Nov. 23. NASA can also procure up to six new flight worthy engines for later launches.
“SLS is America’s next generation heavy lift system,” said Julie Van Kleeck, vice president of Advanced Space & Launch Programs at Aerojet Rocketdyne, in a statement.
“This is the rocket that will enable humans to leave low Earth orbit and travel deeper into the solar system, eventually taking humans to Mars.”
The lead time is approximately 5 or 6 years to build and certify the first new RS-25 engine, Van Kleek told Universe Today in an interview. Therefore NASA needed to award the contract to Aerojet Rocketdyne now so that its ready when needed.
NASA’s Space Launch System (SLS) blasts off from launch pad 39B at the Kennedy Space Center in this artist rendering showing a view of the liftoff of the Block 1 70-metric-ton (77-ton) crew vehicle configuration. Credit: NASA/MSFC
The RS-25 is actually an upgraded version of former space shuttle main engines (SSMEs) originally built by Aerojet Rocketdyne.
The reusable engines were used with a 100% success rate during NASA’s three decade-long Space Shuttle program to propel the now retired shuttle orbiters to low Earth orbit.
Space Shuttles were powered by a trio of Space Shuttle Main Engines (SSMEs) now recycled and upgraded as RS-25 engines for SLS. Atlantis rolls over from the Orbiter Processing Facility (OPF-1, at right) processing hanger to the Vehicle Assembly Building (VAB, at left) at KSC for the STS-135 mission. Credit: Ken Kremer
Those same engines are now being modified for use by the SLS on missions to deep space starting in 2018.
But NASA only has an inventory of 16 of the RS-25 engines, which is sufficient for a maximum of the first four SLS launches only. Although they were reused numerous times during the shuttle era, they will be discarded after each SLS launch.
During a 535-second test on August 13, 2015, operators ran the Space Launch System (SLS) RS-25 rocket engine through a series of tests at different power levels to collect engine performance data on the A-1 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. Credit: NASA
And since the engines cannot be recovered and reused as during the shuttle era, a brand new set of RS-25s will have to be manufactured from scratch.
Therefore, the engine manufacturing process can and will be modernized and significantly streamlined – using fewer part and welds – to cut costs and improve performance.
“The RS-25 engines designed under this new contract will be expendable with significant affordability improvements over previous versions,” added Jim Paulsen, vice president, Program Execution, Advanced Space & Launch Programs at Aerojet Rocketdyne. “This is due to the incorporation of new technologies, such as the introduction of simplified designs; 3-D printing technology called additive manufacturing; and streamlined manufacturing in a modern, state-of-the-art fabrication facility.”
“The new engines will incorporate simplified, yet highly reliable, designs to reduce manufacturing time and cost. For example, the overall engine is expected to simplify key components with dramatically reduced part count and number of welds. At the same time, the engine is being certified to a higher operational thrust level,” says Aerojet Rocketdyne.
The existing stock of 16 RS-25s are being upgraded for use in SLS and also being run through a grueling series of full duration hot fire test firings to certify them for flight, as I reported previously here at Universe Today.
Among the RS-25 upgrades is a new engine controller specific to SLS. The engine controller functions as the “brain” of the engine, which checks engine status, maintains communication between the vehicle and the engine and relays commands back and forth.
RS-25 test firing in progress on the A-1 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, on Aug. 13, 2015. Credit: NASA
Each of the RS-25’s engines generates some 500,000 pounds of thrust. They are fueled by cryogenic liquid hydrogen and liquid oxygen. For SLS they will be operating at 109% of power, compared to a routine usage of 104.5% during the shuttle era. They measure 14 feet tall and 8 feet in diameter.
They have to withstand and survive temperature extremes ranging from -423 degrees F to more than 6000 degrees F.
The maiden test flight of the SLS is targeted for no later than November 2018 and will be configured in its initial 70-metric-ton (77-ton) version with a liftoff thrust of 8.4 million pounds. It will boost an unmanned Orion on an approximately three week long test flight beyond the Moon and back.
NASA plans to gradually upgrade the SLS to achieve an unprecedented lift capability of 130 metric tons (143 tons), enabling the more distant missions even farther into our solar system.
The first SLS test flight with the uncrewed Orion is called Exploration Mission-1 (EM-1) and will launch from Launch Complex 39-B at the Kennedy Space Center.
Orion’s inaugural mission dubbed Exploration Flight Test-1 (EFT) was successfully launched on a flawless flight on Dec. 5, 2014 atop a United Launch Alliance Delta IV Heavy rocket Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Learn more about SLS, Orion, SpaceX, Orbital ATK Cygnus, ISS, ULA Atlas rocket, Boeing, Space Taxis, Mars rovers, Antares, NASA missions and more at Ken’s upcoming outreach events:
Dec 1 to 3: “Orbital ATK Atlas/Cygnus launch to the ISS, ULA, SpaceX, SLS, Orion, Commercial crew, Curiosity explores Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings
Dec 8: “America’s Human Path Back to Space and Mars with Orion, Starliner and Dragon.” Amateur Astronomers Assoc of Princeton, AAAP, Princeton University, Ivy Lane, Astrophysics Dept, Princeton, NJ; 7:30 PM.
A photo of the full moon, taken from Apollo 11 on its way home to Earth, from about 18,520 km (10,000 nm) away. Credit: NASA
People often criticize the amount of money spent on space exploration. Sometimes it’s well-meaning friends and family who say that that money is wasted, and would be better spent on solving problems here on Earth. In fact, that’s a whole cultural meme. You see it played out over and over in the comments section whenever mainstream media covers a space story.
While solving problems here on Earth is noble, and the right thing to do, it’s worth pointing out that the premier space exploration body on Earth, NASA, actually has a tiny budget. When you compare NASA’s budget to what people spend on cigarettes, NASA looks pretty good.
Ignoring for the moment the fact that we don’t know how to solve all the problems here on Earth, let’s look at NASA’s budget over the years, and compare it to something that is truly a waste of money: cigarettes and tobacco.
NASA is over 50 years old. In its first year, its budget was $89 million. (That’s about $732 million in today’s dollars.) In that same year, Americans spent about $6 billion on cigarettes and tobacco.
Buzz Aldrin on the Moon. Image Credit: NASA
From 1969 to 1972, NASA’s Apollo Program landed 12 men on the Moon. They won the Space Race and established a moment that will echo through the ages, no matter what else humanity does: the first human footsteps anywhere other than Earth. In those four years, NASA’s combined budget was $14.8 billion. In that same time period, Americans spent over twice as much—$32 billion—on smoking.
STS-1 Columbia on the launch pad. Image Credit: NASA
In 1981, NASA launched its first space shuttle, the Columbia (STS-1). NASA’s budget that year was $5.5 billion. That same year, the American population spent about $17.4 billion on tobacco. That’s three times NASA’s budget. How many more shuttle flights could there have been? How much more science?
The Hubble Space Telescope in 1997, after its first servicing mission. It’s about 552 km (343m) above Earth. Image: NASA
In 1990, NASA launched the Hubble Space Telescope into Low Earth Orbit (LEO.) The Hubble has been called the most successful science project in history, and Universe Today readers probably don’t need to be told why. The Hubble is responsible for a laundry list of discoveries and observations, and has engaged millions of people around the world in space science and discovery. In that year, NASA had a budget of $12.4 billion. And smoking? In 1990, Americans smoked their way through $26.5 billion of tobacco.
MSL Curiosity selfie on the surface of Mars. Image: NASA/JPL/Cal-Tech.
In 2012, NASA had a budget of $16.8 billion. In that year, NASA successfully landed the Mars Science Laboratory (MSL) Curiosity on Mars, at a cost of $2.5 billion. Also that year, American lungs processed $44 billion worth of tobacco. That’s the equivalent of 17 Curiosity rovers!
There was an enormous scientific debate around where Curiosity should land, in order to maximize the science. Scientific teams competed to have their site chosen, and eventually the Gale Crater was selected as the most promising site. Gale is a meteor crater, and was chosen because it shows signs of running water, as well as evidence of layered geology including clays and minerals.
Sunrise at Gale Crater on Mars. Gale is at center top with the mound in the middle, called Mt. Sharp (Aeolis Mons.)
But other equally tantalizing sites were in contention, including Holden Crater, where a massive and catastrophic flood took place, and where ancient sediments lie exposed on the floor of the crater, ready for study. Or Mawrth Vallis, another site that suffered a massive flood, which exposed layers of clay minerals formed in the presence of water. With the money spent on tobacco in 2012 ($44 billion!) we could have had a top ten list of landing sites on Mars, and put a rover at each one.
Think of all that science.
One of the JWST’s gold-coated mirrors. Not even launched yet, and the golden mirrors are already iconic. Image Credit: NASA/Drew Noel
NASA’s budget is always a source of controversy, and that’s certainly true of another of NASA’s big projects: The James Webb Space Telescope (JWST.) Space enthusiasts are eagerly awaiting the launch of the JWST, planned for October 2018. The JWST will take up residence at the second Lagrange Point (L2,) where it will spend 5-10 years studying the formation of galaxies, stars, and planetary systems from the Big Bang until now. It will also investigate the potential for life in other solar systems.
The L2 (Lagrange 2) point in space. Image Credit: NASA
Initially the JWST’s cost was set at $1.6 billion and it was supposed to launch in 2011. But now it’s set for October 2018, and its cost has grown to $8.8 billion. It sounds outrageous, almost $9 billion for a space telescope, and Congress considered scrapping the entire project. But what’s even more outrageous is that Americans are projected to spend over $50 billion on tobacco in 2018.
When people in the future look back at NASA and what it was able to accomplish in the latter half of the 20th century and the beginning of the 21st century, they’ll think two things: First, they’ll think how amazing it was that NASA did what it did. The Moon landings, the Shuttle program, the Hubble, Curiosity, and the James Webb.
Then, they’ll be saddened by how much more could’ve been done collectively, if so much money hadn’t been wasted on something as deadly as smoking.
The International Space Station (ISS) has grown tremendously in size and complexity and evolved significantly over 15 years of continuous human occupation from Nov. 2, 2000 to Nov. 2, 2015. Credit: NASA
The International Space Station (ISS) achieved 15 years of a continuous human presence in orbit, as of today, Nov. 2, aboard the football field sized research laboratory ever since the first Russian/American crew of three cosmonauts and astronauts comprising Expedition 1 arrived in a Soyuz capsule at the then much tinier infant orbiting complex on Nov. 2, 2000.
Today, the space station is host to the Expedition 45 crew of six humans – from America, Russia and Japan – that very symbolically also includes the first ever crew spending one year aboard and that highlights the outposts expanding role from a research lab to a deep space exploration test bed for experiments and technologies required for sending humans on interplanetary journeys to the Martian system in the 2030s.
The ISS was only made possible by over two decades of peaceful and friendly international cooperation by the most powerful nations on Earth on a scale rarely seen.
“I believe the International Space Station should be considered for the Nobel Peace Prize,” said NASA Administrator Charles Bolden last week during remarks to the Center for American Progress in Washington, DC., on October 28, 2015.
“Exploration has taught us more than we have ever known about our Universe and our place in it.”
“The ISS has already taught us what’s possible when tens of thousands of people across 15 countries collaborate so that human beings from different nations can live and work in space together.”
“Yet, for all these accomplishments, when you consider all the possibilities ahead of us you can only reach one conclusion; We are just getting started!”
6 person ISS Expedition 45 Crew celebrates 15 Years of operation with humans on 2 Nov 2015. Credit: NASA
“No better place to celebrate #15YearsOnStation! #HappyBday, @space_station! Thanks for the hospitality! #YearInSpace.” tweeted NASA astronaut Scott Kelly from the ISS today along with a crew portrait.
The space station is the largest engineering and construction project in space combining the funding, hardware, knowhow, talents and crews from 5 space agencies and 15 countries – NASA, Roscomos, ESA (European Space Agency), JAXA (Japan Aerospace and Exploration Agency) and CSA (Canadian Space Agency).
NASA astronaut Tracy Caldwell Dyson, an Expedition 24 flight engineer in 2010, took a moment during her space station mission to enjoy an unmatched view of home through a window in the Cupola of the International Space Station, the brilliant blue and white part of Earth glowing against the blackness of space. Credits: NASA
The collaborative work in space has transcended our differences here on Earth and points the way forward to an optimistic future that benefits all humanity.
The station orbits at an altitude of about 250 miles (400 kilometers) above Earth. It measures 357 feet (109 meters) end-to-end and has an internal pressurized volume of 32,333 cubic feet, equivalent to that of a Boeing 747.
The uninterrupted human presence on the station all began when Expedition 1 docked at the outpost on Nov. 2, 2000, with its first residents including Commander William Shepherd of NASA and cosmonauts Sergei Krikalev and Yuri Gidzenko of Roscosmos.
For the first station trio in November 2000, the vehicle included three modules; the Zarya module and the Zvezda service module from Russia and the Unity module from the US.
In this photo, Expedition 1 crew members (from left to right) Commander Bill Shepherd, and Flight Engineers Yuri Gidzenko and Sergei Krikalev pose with a model of their home away from home. Image Credit: NASA
Over the past 15 years, after more than 115 construction and logistics flight, the station has grown by leaps and bounds from its small initial configuration of only three pressurized modules from Russian and America into a sprawling million pound orbiting outpost sporting a habitable volume the size of a six bedroom house, with additional new modules and hardware from Europe, Japan and Canada.
The ISS has been visited by over 220 people from 17 countries.
The “1 Year ISS crew” reflects the international cooperation that made the station possible and comprises current ISS commander NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko, who are now just past the half way mark of their mission.
“Over the weekend, I called NASA astronaut Scott Kelly, who is currently halfway through his one-year mission aboard the International Space Station, to congratulate him on setting the American records for both cumulative and continuous days in space,” Bolden said in a NASA statement released today.
“I also took the opportunity to congratulate Commander Kelly — and the rest of the space station crew — for being part of a remarkable moment 5,478 days in the making: the 15th anniversary of continuous human presence aboard the space station.”
Scott Kelly, U.S. astronaut and commander of the current Expedition 45 crew, broke the US record for time spent in space on Oct. 16, 2015. Credit: NASA
The complete Expedition 45 crew members include Station Commander Scott Kelly and Flight Engineer Kjell Lindgren of NASA, Flight Engineers Mikhail Kornienko, Oleg Kononenko and Sergey Volkov of the Russian Federal Space Agency (Roscosmos) and Flight Engineer Kimiya Yui of the Japan Aerospace Exploration Agency.
For the first nine years, the station was home to crews of two or three. Starting in 2009 the crew size was doubled to a permanent crew of six humans after the habitable volume, research facilities, equipment and supporting provisions had grown sufficiently.
“Humans have been living in space aboard the International Space Station 24-7-365 since Nov. 2, 2000. That’s 15 Thanksgivings, New Years, and holiday seasons astronauts have spent away from their families. 15 years of constant support from Mission Control Houston. And 15 years of peaceful international living in space,” says NASA.
Expedition 45 Crew Portrait: Station Commander Scott Kelly and Flight Engineer Kjell Lindgren of NASA, Flight Engineers Mikhail Kornienko, Oleg Kononenko and Sergey Volkov of the Russian Federal Space Agency (Roscosmos) and Flight Engineer Kimiya Yui of the Japan Aerospace Exploration Agency. Credit: NASA/Roscosmos/JAXA
The US contributed and built the largest number of segments of the space station, followed by Russia.
NASA’s Space Shuttles hauled the US segments aloft inside the orbiters huge payload bay, starting from the first construction mission in 1998 carrying the Unity module to the final shuttle flight STS-135 in 2011, which marked the completion of construction and retirement of the shuttles.
With the shuttle orbiters now sitting in museums and no longer flying, the Russian Soyuz capsule is the only means of transporting crews to the space station and back.
The longevity of the ISS was recently extended from 2020 to 2024 after approval from President Obama. Most of the partners nations have also agreed to the extension. Many in the space community believe the station hardware is quite resilient and hope for further extensions to 2028 and beyond.
“The International Space Station, which President Obama has extended through 2024, is a testament to the ingenuity and boundless imagination of the human spirit. The work being done on board is an essential part of NASA’s journey to Mars, which will bring American astronauts to the Red Planet in the 2030s,” says Bolden.
“For 15 years, humanity’s reach has extended beyond Earth’s atmosphere. Since 2000, human beings have been living continuously aboard the space station, where they have been working off-the-Earth for the benefit of Earth, advancing scientific knowledge, demonstrating new technologies, and making research breakthroughs that will enable long-duration human and robotic exploration into deep space.”
A key part of enabling long duration space missions to Mars is the 1 Year ISS Mission.
In coming years, additional new pressurized modules and science labs will be added by Russia and the US.
And NASA says the stations crew size will expand to seven after the US commercial Starliner and Dragon space taxis from Boeing and SpaceX start flying in 2017.
NASA is now developing the new Orion crew capsule and mammoth Space Launch System (SLS) heavy lift rocket to send astronauts to deep space destination including the Moon, asteroids and the Red Planet.
In the meantime, Kelly and his crew are also surely looking forward to the arrival of the next Orbital ATKCygnus resupply ship carrying science experiments, provisions, spare parts, food and other goodies after it blasts off from Florida on Dec. 3 – detailed in my story here.
Infographic: 15 Years of Continuous Human Presence Aboard the International Space Station. Credit: NASA
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
STS-135: Last launch using RS-25 engines that will now power NASA’s SLS deep space exploration rocket. NASA’s 135th and final shuttle mission takes flight on July 8, 2011 at 11:29 a.m. from the Kennedy Space Center in Florida bound for the final flight to the ISS and the high frontier with Chris Ferguson as Space Shuttle Commander. Credit: Ken Kremer/kenkremer.com
NASA’s Space Launch System (SLS) blasts off from launch pad 39B at the Kennedy Space Center in this artist rendering showing a view of the liftoff of the Block 1 70-metric-ton (77-ton) crew vehicle configuration. Credit: NASA/MSFC
NASA’s Space Launch System (SLS) blasts off from launch pad 39B at the Kennedy Space Center in this artist rendering showing a view of the liftoff of the Block 1 70-metric-ton (77-ton) crew vehicle configuration. Credit: NASA/MSFC
Story/imagery updated[/caption]
The SLS, America’s first human-rated heavy lift rocket intended to carry astronautsto deep space destinations since NASA’s Apollomoon landing era Saturn V, has passed a key design milestone known as the critical design review (CDR) thereby clearing the path to full scale fabrication.
NASA also confirmed they have dropped the Saturn V white color motif of the mammoth rocket in favor of burnt orange to reflect the natural color of the SLS boosters first stage cryogenic core. The agency also decided to add stripes to the huge solid rocket boosters.
NASA announced that the Space Launch System (SLS) has “completed all steps needed to clear a critical design review (CDR)” – meaning that the design of all the rockets components are technically acceptable and the agency can continue with full scale production towards achieving a maiden liftoff from the Kennedy Space Center in Florida in 2018.
“We’ve nailed down the design of SLS,” said Bill Hill, deputy associate administrator of NASA’s Exploration Systems Development Division, in a NASA statement.
Artist concept of the SLS Block 1 configuration on the Mobile Launcher at KSC. Credit: NASA/MSFC
Blastoff of the NASA’s first SLS heavy lift booster (SLS-1) carrying an unmanned test version of NASA’s Orioncrew capsule is targeted for no later than November 2018.
Indeed the SLS will be the most powerful rocket the world has ever seen starting with its first liftoff. It will propel our astronauts on journey’s further into space than ever before.
SLS is “the first vehicle designed to meet the challenges of the journey to Mars and the first exploration class rocket since the Saturn V.”
Crews seated inside NASA’s Orion crew module bolted atop the SLS will rocket to deep space destinations including the Moon, asteroids and eventually the Red Planet.
“There have been challenges, and there will be more ahead, but this review gives us confidence that we are on the right track for the first flight of SLS and using it to extend permanent human presence into deep space,” Hill stated.
The core stage (first stage) of the SLS will be powered by four RS-25 engines and a pair of five-segment solid rocket boosters (SRBs) that will generate a combined 8.4 million pounds of liftoff thrust in its inaugural Block 1 configuration, with a minimum 70-metric-ton (77-ton) lift capability.
Overall the SLS Block 1 configuration will be some 10 percent more powerful than the Saturn V rockets that propelled astronauts to the Moon, including Neil Armstrong, the first human to walk on the Moon during Apollo 11 in July 1969.
Graphic shows Block I configuration of NASA’s Space Launch System (SLS). Credits: NASA/MSFC
The SLS core stage is derived from the huge External Tank (ET) that fueled NASA Space Shuttle’s for three decades. It is a longer version of the Shuttle ET.
NASA initially planned to paint the SLS core stage white, thereby making it resemble the Saturn V.
But since the natural manufacturing color of its insulation during fabrication is burnt orange, managers decided to keep it so and delete the white paint job.
“As part of the CDR, the program concluded the core stage of the rocket and Launch Vehicle Stage Adapter will remain orange, the natural color of the insulation that will cover those elements, instead of painted white,” said NASA.
There is good reason to scrap the white color motif because roughly 1000 pounds of paint can be saved by leaving the tank with its natural orange pigment.
This translates directly into another 1000 pounds of payload carrying capability to orbit.
“Not applying the paint will reduce the vehicle mass by potentially as much as 1,000 pounds, resulting in an increase in payload capacity, and additionally streamlines production processes,” Shannon Ridinger, NASA Public Affairs spokeswomen told Universe Today.
After the first two shuttle launches back in 1981, the ETs were also not painted white for the same reason – in order to carry more cargo to orbit.
“This is similar to what was done for the external tank for the space shuttle. The space shuttle was originally painted white for the first two flights and later a technical study found painting to be unnecessary,” Ridinger explained.
Artist concept of the Block I configuration of NASA’s Space Launch System (SLS). The SLS Program has completed its critical design review, and the program has concluded that the core stage of the rocket will remain orange along with the Launch Vehicle Stage Adapter, which is the natural color of the insulation that will cover those elements. Credits: NASA
NASA said that the CDR was completed by the SLS team in July and the results were also further reviewed over several more months by a panel of outside experts and additionally by top NASA managers.
“The SLS Program completed the review in July, in conjunction with a separate review by the Standing Review Board, which is composed of seasoned experts from NASA and industry who are independent of the program. Throughout the course of 11 weeks, 13 teams – made up of senior engineers and aerospace experts across the agency and industry – reviewed more than 1,000 SLS documents and more than 150 GB of data as part of the comprehensive assessment process at NASA’s Marshall Space Flight Center in Huntsville, Alabama, where SLS is managed for the agency.”
“The Standing Review Board reviewed and assessed the program’s readiness and confirmed the technical effort is on track to complete system development and meet performance requirements on budget and on schedule.”
The final step of the SLS CDR was completed this month with another extremely thorough assessment by NASA’s Agency Program Management Council, led by NASA Associate Administrator Robert Lightfoot.
“This is a major step in the design and readiness of SLS,” said John Honeycutt, SLS program manager.
The CDR was the last of four reviews that examine SLS concepts and designs.
NASA says the next step “is design certification, which will take place in 2017 after manufacturing, integration and testing is complete. The design certification will compare the actual final product to the rocket’s design. The final review, the flight readiness review, will take place just prior to the 2018 flight readiness date.”
“Our team has worked extremely hard, and we are moving forward with building this rocket. We are qualifying hardware, building structural test articles, and making real progress,” Honeycutt elaborated.
Numerous individual components of the SLS core stage have already been built and their manufacture was part of the CDR assessment.
The SLS core stage is being built at NASA’s Michoud Assembly Facility in New Orleans. It stretches over 200 feet tall and is 27.6 feet in diameter and will carry cryogenic liquid hydrogen and liquid oxygen fuel for the rocket’s four RS-25 engines.
On Sept. 12, 2014, NASA Administrator Charles Bolden officially unveiled the world’s largest welder at Michoud, that will be used to construct the core stage, as I reported earlier during my on-site visit – here.
NASA decided that the SRBs will be painted with something like racing stripes.
“Stripes will be painted on the SRBs and we are still identifying the best process for putting them on the boosters; we have multiple options that have minimal impact to cost and payload capability, ” Ridinger stated.
With the successful completion of the CDR, the components of the first core stage can now proceed to assembly of the finished product and testing of the RS-25 engines and boosters can continue.
“We’ve successfully completed the first round of testing of the rocket’s engines and boosters, and all the major components for the first flight are now in production,” Hill explained.
View of NASA’s future SLS/Orion launch pad at Space Launch Complex 39B from atop Mobile Launcher at the Kennedy Space Center in Florida. Former Space Shuttle launch pad 39B is now undergoing renovations and upgrades to prepare for SLS/Orion flights starting in 2018. Credit: Ken Kremer/kenkremer.com
NASA plans to gradually upgrade the SLS to achieve an unprecedented lift capability of 130 metric tons (143 tons), enabling the more distant missions even farther into our solar system.
The first SLS test flight with the uncrewed Orion is called Exploration Mission-1 (EM-1) and will launch from Launch Complex 39-B at the Kennedy Space Center (KSC).
The SLS/Orion stack will roll out to pad 39B atop the Mobile Launcher now under construction – as detailed in my recent story and during visit around and to the top of the ML at KSC.
Looking up from beneath the enlarged exhaust hole of the Mobile Launcher to the 380 foot-tall tower astronauts will ascend as their gateway for missions to the Moon, Asteroids and Mars. The ML will support NASA’s Space Launch System (SLS) and Orion spacecraft during Exploration Mission-1 at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
Orion’s inaugural mission dubbed Exploration Flight Test-1 (EFT) was successfully launched on a flawless flight on Dec. 5, 2014 atop a United Launch Alliance Delta IV Heavy rocket Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Wide view of the new welding tool at the Vertical Assembly Center at NASA’s Michoud Assembly Facility in New Orleans at a ribbon-cutting ceremony Sept. 12, 2014. Credit: Ken Kremer – kenkremer.com
During a 535-second test on August 13, 2015, operators ran the Space Launch System (SLS) RS-25 rocket engine through a series of tests at different power levels to collect engine performance data on the A-1 test stand at NASA's Stennis Space Center near Bay St. Louis, Mississippi. Credit: NASA
During a 535-second test on August 13, 2015, operators ran the Space Launch System (SLS) RS-25 rocket engine through a series of tests at different power levels to collect engine performance data on the A-1 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. Credit: NASA Story/imagery updated
See video below of full duration hot-fire test[/caption]
With today’s (Aug. 13) successful test firing of an RS-25 main stage engine for NASA’s Space Launch System (SLS) monster rocket currently under development, the program passed a key milestone advancing the agency on the path to propel astronauts back to deep space at the turn of the decade.
The 535 second long test firing of the RS-25 development engine was conducted on the A-1 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi – and ran for the planned full duration of nearly 9 minutes, matching the time they will fire during an actual SLS launch.
All indications are that the hot fire test apparently went off without a hitch, on first look.
“We ran the full duration and met all test objectives,” said Steve Wofford, SLS engine manager, on NASA TV following today’s’ test firing.
“There were no anomalies.” – based on the initial look.
The RS-25 is actually an upgraded version of former space shuttle main engines that were used with a 100% success rate during NASA’s three decade-long Space Shuttle program to propel the now retired shuttle orbiters to low Earth orbit. Those same engines are now being modified for use by the SLS.
Spectators enjoy the view during the Aug. 13, 2015 test firing of the RS-25 engine for NASA’s Space Launch System (SLS) on the A-1 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. Credit: NASA
“Data collected on performance of the engine at the various power levels will aid in adapting the former space shuttle engines to the new SLS vehicle mission requirements, including development of an all-new engine controller and software,” according to NASA officials .
The engine controller functions as the “brain” of the engine, which checks engine status, maintains communication between the vehicle and the engine and relays commands back and forth.
The core stage (first stage) of the SLS will be powered by four RS-25 engines and a pair of the five-segment solid rocket boosters that will generate a combined 8.4 million pounds of liftoff thrust, making it the most powerful rocket the world has ever seen.
Since shuttle orbiters were equipped with three space shuttle main engines, the use of four RS-25s on the SLS represents another significant change that also required many modifications being thoroughly evaluated as well.
RS-25 test firing in progress on the A-1 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, on Aug. 13, 2015. Credit: NASA
The SLS will be some 10 percent more powerful than the Saturn V rockets that propelled astronauts to the Moon, including Neil Armstrong, the human to walk on the Moon during Apollo 11 in July 1969.
SLS will loft astronauts in the Orion capsule on missions back to the Moon by around 2021, to an asteroid around 2025 and then beyond on a ‘Journey to Mars’ in the 2030s – NASA’s overriding and agency wide goal.
Each of the RS-25’s engines generates some 500,000 pounds of thrust. They are fueled by cryogenic liquid hydrogen and liquid oxygen. For SLS they will be operating at 109% of power, compared to a routine usage of 104.5% during the shuttle era. They measure 14 feet tall and 8 feet in diameter.
They have to withstand and survive temperature extremes ranging from -423 degrees F to more than 6000 degrees F.
This video shows the full duration hot-fire test:
NASA has 16 of the RS-25s leftover from the shuttle era and they are all being modified and upgraded for use by the SLS rocket.
Today’s test was the sixth in a series of seven to qualify the modified engines to flight status. The engine ignited at 5:01 p.m. EDT and reached the full thrust level of 512,000 pounds within about 5 seconds.
The hot gas was exhausted out of the nozzle at 13 times the speed of sound.
Since the shuttle engines were designed and built over three decades ago, they are being modified where possible with state of the art components to enhance performance, functionality and ease of operation, by prime contractor Aerojet-Rocketdyne of Sacramento, California.
One of the key objectives of today’s engine firing and the entire hot fire series was to test the performance of a brand new engine controller assembled with modern manufacturing techniques.
“Operators on the A-1 Test Stand at Stennis are conducting the test series to qualify an all-new engine controller and put the upgraded former space shuttle main engines through the rigorous temperature and pressure conditions they will experience during a SLS mission,” says NASA.
“The new controller, or “brain,” for the engine, which monitors engine status and communicates between the vehicle and the engine, relaying commands to the engine and transmitting data back to the vehicle. The controller also provides closed-loop management of the engine by regulating the thrust and fuel mixture ratio while monitoring the engine’s health and status.’
Video caption: RS-25 – The Ferrari of Rocket Engines explained. Credit: NASA
“The RS-25 is the most complicated rocket engine out there on the market, but that’s because it’s the Ferrari of rocket engines,” says Kathryn Crowe, RS-25 propulsion engineer.
“When you’re looking at designing a rocket engine, there are several different ways you can optimize it. You can optimize it through increasing its thrust, increasing the weight to thrust ratio, or increasing its overall efficiency and how it consumes your propellant. With this engine, they maximized all three.”
Engineers will now pour over the data collected from hundreds of data channels in great detail to thoroughly analyze the test results. They will incorporate any findings into future test firings of the RS-25s.
NASA says that testing of RS-25 flight engines is set to start later this fall.
“The RS-25 engine gives SLS a proven, high performance, affordable main propulsion system for deep space exploration. It is one of the most experienced large rocket engines in the world, with more than a million seconds of ground test and flight operations time.”
NASA plans to buy completely new sets of RS-25 engines from Aerojet-Rocketdyne taking full advantage of technological advances and modern manufacturing techniques as well as lessons learned from this hot fire series of engine tests.
The maiden test flight of the SLS is targeted for no later than November 2018 and will be configured in its initial 70-metric-ton (77-ton) version with a liftoff thrust of 8.4 million pounds. It will boost an unmanned Orion on an approximately three week long test flight beyond the Moon and back.
Artist concept of the SLS Block 1 configuration. Credit: NASA
NASA plans to gradually upgrade the SLS to achieve an unprecedented lift capability of 130 metric tons (143 tons), enabling the more distant missions even farther into our solar system.
The first SLS test flight with the uncrewed Orion is called Exploration Mission-1 (EM-1) and will launch from Launch Complex 39-B at the Kennedy Space Center.
NASA’s first Orion spacecraft blasts off at 7:05 a.m. atop United Launch Alliance Delta 4 Heavy Booster at Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida on Dec. 5, 2014. Credit: Ken Kremer – kenkremer.com
Orion’s inaugural mission dubbed Exploration Flight Test-1 (EFT) was successfully launched on a flawless flight on Dec. 5, 2014 atop a United Launch Alliance Delta IV Heavy rocket Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
NASA Administrator Charles Bolden officially unveils world’s largest welder to start construction of core stage of NASA’s Space Launch System (SLS) rocket at NASA Michoud Assembly Facility, New Orleans, on Sept. 12, 2014. SLS will be the world’s most powerful rocket ever built. Credit: Ken Kremer – kenkremer.comSTS-135: Last launch using RS-25 engines that will now power NASA’s SLS deep space exploration rocket. NASA’s 135th and final shuttle mission takes flight on July 8, 2011 at 11:29 a.m. from the Kennedy Space Center in Florida bound for the ISS and the high frontier with Chris Ferguson as Space Shuttle Commander. Credit: Ken Kremer/kenkremer.com
Artist's concept of a Bimodal Nuclear Thermal Rocket in Low Earth Orbit. Credit: NASA
In the past four decades, NASA and other space agencies from around the world have accomplished some amazing feats. Together, they have sent manned missions to the Moon, explored Mars, mapped Venus and Mercury, conducted surveys, and captured breathtaking images of the Outer Solar System. However, looking ahead to the next generation of exploration and the more-distant frontiers that remain to be explored, it is clear that new ideas need to be put forward on how to quickly and efficiently reach those destinations.
Basically, this means finding ways to power rockets that are more fuel and cost-effective while still providing the necessary power to get crews, rovers, and orbiters to their far-flung destinations. In this respect, NASA has been taking a good look at nuclear fission as a possible means of propulsion.
In fact, according to a presentation made by Doctor Michael G. Houts of the NASA Marshall Space Flight Center back in October of 2014, nuclear power and propulsion have the potential to be “game-changing technologies for space exploration.”
As the Marshall Space Flight Center’s manager of nuclear thermal research, Dr. Houts is well-versed in the benefits it has to offer space exploration. According to the presentation he and fellow staffers made, a fission reactor can be used in a rocket design to create Nuclear Thermal Propulsion (NTP). In an NTP rocket, uranium or deuterium reactions are used to heat liquid hydrogen inside a reactor, turning it into ionized hydrogen gas (plasma), which is then channeled through a rocket nozzle to generate thrust.
NASA design for a Nuclear Engine for Rocket Vehicle Application (NERVA). Image Credit: NASA
A second possible method, known as Nuclear Electric Propulsion (NEP), involves the same basic reactor converting its heat and energy into electrical energy which then powers an electrical engine. In both cases, the rocket relies on nuclear fission to generate propulsion rather than chemical propellants, which has been the mainstay of NASA and all other space agencies to date.
Compared to this traditional form of propulsion, both NTP and NEP offer a number of advantages. The first and most obvious is the virtually unlimited energy density it offers compared to rocket fuel. At a steady state, a fission reactor produces an average of 2.5 neutrons per reaction. However, it would only take a single neutron to cause a subsequent fission and produce a chain reaction and provide constant power.
In fact, according to the report, an NTP rocket could generate 200 kWt of power using a single kilogram of uranium for a period of 13 years – which works out to a fuel efficiency rating of about 45 grams per 1000 MW-hr.
In addition, a nuclear-powered engine could also provide superior thrust relative to the amount of propellant used. This is what is known as specific impulse, which is measured either in terms of kilo-newtons per second per kilogram (kN·s/kg) or in the amount of seconds the rocket can continually fire. This would cut the total amount of propellent needed, thus cutting launch weight and the cost of individual missions. And a more powerful nuclear engine would mean reduced trip times, another cost-cutting measure.
The key elements of a NERVA solid-core nuclear-thermal engine. Credit: NASA
Although no nuclear-thermal engines have ever flown, several design concepts have been built and tested over the past few decades, and numerous concepts have been proposed. These have ranged from the traditional solid-core design to more advanced and efficient concepts that rely on either a liquid or a gas core.
In the case of a solid-core design, the only type that has ever been built, a reactor made from materials with a very high melting point houses a collection of solid uranium rods which undergo controlled fission. The hydrogen fuel is contained in a separate tank and then passes through tubes around the reactor, gaining heat and converted into plasma before being channeled through the nozzles to achieve thrust.
Using hydrogen propellant, a solid-core design typically delivers specific impulses on the order of 850 to 1000 seconds, which is about twice that of liquid hydrogen-oxygen designs – i.e. the Space Shuttle’s main engine.
However, a significant drawback arises from the fact that nuclear reactions in a solid-core model can create much higher temperatures than conventional materials can withstand. The cracking of fuel coatings can also result from large temperature variations along the length of the rods, which taken together, sacrifices much of the engine’s potential for performance.
Diagram of an open-cycle, gas design for a nuclear-thermal rocket engine. Credit: NASA
Many of these problems were addressed with the liquid core design, where nuclear fuel is mixed into the liquid hydrogen and the fission reaction takes place in the liquid mixture itself. This design can operate at temperatures above the melting point of the nuclear fuel, thanks to the fact that the container wall is actively cooled by the liquid hydrogen. It is also expected to deliver a specific impulse performance of 1300 to 1500 (1.3 to 1.5 kN·s/kg) seconds.
However, compared to the solid-core design, engines of this type are much more complicated and therefore more expensive and difficult to build. Part of the problem has to do with the time it takes to achieve a fission reaction, which is significantly longer than the time it takes to heat the hydrogen fuel. Therefore, engines of this kind require methods to trap the fuel inside the engine while simultaneously allowing heated plasma the ability to exit through the nozzle.
The final classification is the gas-core engine, a modification of the liquid-core design that uses rapid circulation to create a ring-shaped pocket of gaseous uranium fuel in the middle of the reactor that is surrounded by liquid hydrogen. In this case, the hydrogen fuel does not touch the reactor wall, so temperatures can be kept below the melting point of the materials used.
An engine of this kind could allow for specific impulses of 3000 to 5000 seconds (30 to 50 kN·s/kg). But in an “open-cycle” design of this kind, the losses of nuclear fuel would be difficult to control. An attempt to remedy this was drafted with the “closed cycle design” – aka. the “nuclear lightbulb” engine – where the gaseous nuclear fuel is contained in a series of super-high-temperature quartz containers.
The closed-concept (aka. Lightbulb) gas core nuclear-thermal rocket engine. Credit: NASA
Although this design is less efficient than the open-cycle design and has more in common with the solid-core concept, the limiting factor here is the critical temperature of quartz and not that of the fuel stack. What’s more, the closed-cycle design is expected to still deliver a respectable specific impulse of about 1500–2000 seconds (15–20 kN·s/kg).
However, as Houts indicated, one of the greatest assets nuclear fission has going for it is the long history of service it has enjoyed here on Earth. In addition to commercial reactors providing electricity all over the world, naval vessels (such as aircraft carriers and submarines) have made good use of slow-fission reactors for decades.
Also, NASA has been relying on nuclear reactors to power unmanned craft and rovers for over four decades, mainly in the form of Radioisotope Thermoelectric Generators (RTGs) and Radioisotope Heater Units (RHU). In the case of the former, heat is generated by the slow decay of plutonium-238 (Pu-238), which is then converted into electricity. In the case of the latter, the heat itself is used to keep components and ship systems warm and running.
These types of generators have been used to power and maintain everything from the Apollo rockets to the Curiosity Rover, as well as countless satellites, orbiters and robots in between. Since its inception,a total of 44 missions have been launched by NASA that have used either RTGs or RHUs, while the former-Soviet space program launched a comparatively solid 33.
Using modular components, a NTP spacecraft could be fitted for numerous mission profiles. Credit: NASA
Nuclear engines were also considered for a time as a replacement for the J-2, a liquid-fuel cryogenic rocket engine used on the S-II and S-IVB stages on the Saturn V and Saturn I rockets. But despite there being numerous versions of solid-core reactors produced and tested in the past, none were ever put into service for an actual space flight.
Between 1959 and 1972, the United States tested twenty different sizes and designs during Project Rover and NASA’s Nuclear Engine for Rocket Vehicle Application (NERVA) program. The most powerful engine ever tested was the Phoebus 2a, which operated for a total of 32 minutes and maintained power levels of more than 4.0 million kilowatts for 12 minutes.
But looking to the future, Houts’ and the Marshall Space Flight Center see great potential and many possible applications for this technology. Examples cited in the report include long-range satellites that could explore the Outer Solar System and Kuiper Belt, fast, efficient transportation for manned missions throughout the Solar System, and even the provisions of power for settlements on the Moon and Mars someday.
One possibility is to equip NASA’s latest flagship – the Space Launch System (SLS) – with chemically-powered lower-stage engines and a nuclear-thermal engine on its upper stage. The nuclear engine would remain “cold” until the rocket had achieved orbit, at which point the upper stage would be deployed and the reactor would be activated to generate thrust.
NASA proposals for nuclear-powered exploration rovers and craft. Credit: NASA
This concept for a “bimodal” rocket – one which relies on chemical propellants to achieve orbit and a nuclear-thermal engine for propulsion in space – could become the mainstay of NASA and other space agencies in the coming years. According to Houts and others at Marshall, the dramatic increase in efficiency offered by such rockets could also facilitate NASA’s plans to explore Mars by allowing for the reliable delivery of high-mass automated payloads in advance of manned missions.
These same rockets could then be retooled for speed (instead of mass) and used to transport the astronauts themselves to Mars in roughly half the time it would take for a conventional rocket to make the trip. This would not only save time and cut mission costs but also ensure that the astronauts were exposed to less harmful solar radiation during the course of their flight.
To see this vision become reality, Dr. Houts and other researchers from the Marshall Space Center’s Propulsion Research and Development Laboratory are currently conducting NTP-related tests at the Nuclear Thermal Rocket Element Environmental Simulator (or “NTREES”) in Huntsville, Alabama.
Here, they have spent the past few years analyzing the properties of various nuclear fuels in a simulated thermal environment, hoping to learn more about how they might affect engine performance and longevity when it comes to a nuclear-thermal rocket engine.
Concept art showing a nuclear thermal propulsion piloted craft achieving Mars orbit. Credit: NASA
These tests are slated to run until June 2015 and are expected to lay the groundwork for large-scale ground tests and eventual full-scale testing in flight. The ultimate goal of all of this is to ensure that a manned mission to Mars takes place by the 2030s and to provide NASA flight engineers and mission planners with all the information they need to see it through.
But of course, it is also likely to have its share of applications when it comes to future Lunar missions, sending crews to study Near-Earth Objects (NEOs), and sending craft to the Jovian moons and other locations in the outer Solar System. As the report shows, NTP craft can be easily modified using modular components to perform everything from Lunar cargo landings to crewed missions to surveying Near-Earth Asteroids (NEAs).
The Universe is a big place, and space exploration is still very much in its infancy. But if we intend to keep exploring it and reaping the rewards that such endeavors have to offer, our methods will have to mature. NTP is merely one proposed possibility. But unlike Nuclear Pulse Propulsion, the Daedalus concept, anti-matter engines, or the Alcubierre Warp Drive, a rocket that runs on nuclear fission is feasible, practical, and possible within the near future.
Nuclear thermal research at the Marshall Center is part of NASA’s Advanced Exploration Systems (AES) Division, managed by the Human Exploration and Operations Mission Directorate and including participation by the U.S. Department of Energy.
