Humans have dreamed of a day when we could explore nearby stars and settle extrasolar planets since astronomer found that Earth and the Solar System are not unique. The laws of physics impose strict limitations on how fast things can travel in our universe. The speed of light is constant and absolute, and objects approaching it will experience an increase in their inertial mass.
There is a loophole that may allow for Faster- Than- Light travel. The Alcubierre Warp Metric describes a warp field that contracts spacetime in front of a spaceship and expands it behind it. This would allow the spaceship to travel faster than light, while not violating the laws of causality. For more than a decade, Dr. Harold White has been investigating this theory in the hopes of bringing it closer to reality.
Dr. White was involved in the development of an Alcubierre Warp Drive at the NASA Eagleworks at the Johnson Space Center. The Limitless Space Institute is a non-profit organization dedicated to education, outreach, research grants, and the development of advanced propulsion methods, which they hope will lead to the creation of the first warp drive!
The idea ofwarp drives and FTL have been with us for a long time, but they have mostly been science fiction. It wasn't until 1994 that an actual proposal was made to explain how FTL could work. The credit for this goes to Mexican theoretical physicist Miguel Alcubierre, who proposed what would become known as the Alcubierre Drive.
The warp drive: hyper-fast travel within general relativity was the topic of his research paper. It was possible if a field could be created with a lower energy density than the vacuum of space.
The existence of regions of spacetime with negative energy densities is possible thanks to quantum field theory. The attractive force between two surfaces in a vacuum is known as the Casimir Effect. Spacetime could theoretically be contracted in front of the ship if a negative mass could be created around it. The speed of light is slower than the speed of the spaceship.
He wrote that it was possible to move faster than the speed of light seen by observers outside the disturbed region, by a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it. Exotic matter will be needed in order to create a distortion of spacetime.
Dr. White used an everyday metaphor to explain the concept to Universe Today. He said it was like using horizontal conveyor belts at major airports.
“Normally, you walk along at about three miles an hour going from one gate to another. But in some locations, you have these horizontal ‘travelators,’ and you step on top of them. So you’re still walking at three miles an hour, but the belt is moving as well. Conceptually speaking, the belt is contracting space in front of you and expanding space behind you, so that it augments your apparent speed. But locally, you’re still going at the same speed.”
This way, an object wouldn't be violating Relativity since it is riding a wave generated by the expansion and contraction of local spacetime. This would allow for circumventing the problems of time dilation, where time slows down as objects approach the speed of light, and the massive increase in inertial mass. Ah, but there was a problem.
According to Alcubierre's original paper, the amount of negative mass required to achieve a warp field was beyond anything humanity could achieve. Since he first proposed it, some of the strict energy requirements that he outlined have been reconsidered. The amount of exotic matter required to generate a warp field may be within the realm of possibility.
Dr. White's revised take on the Alcubierre Metric came while he was preparing to deliver a speech at the first 100 Year Starship symposium, a joint project hosted by NASA and the Defense Advanced Research Projects Agency.
“I was asked to give a talk about space works at the inaugural NASA-DARPA 100 Year Starship symposium. I didn’t just want to rehash what I had already talked about in the past, so I went through and did some sensitivity analysis with the field equations. I was looking at what happens when you change some of the input parameters to the preliminary requirement for the phenomena – just because I wanted to have something new to talk about.
“In the process of that, it became very clear that you could significantly reduce the amount of negative vacuum energy density that’s necessary to make the trick work, non-trivially so. The stuff I published in 11′, 12′, and 13′ – three different conferences back to back- I was able to duplicate the best prediction that had been done prior to that by my colleague.”
Richard Obousy was a co-founding partner of Project Icarus. In a study released that same year, Obousy and co-author Aram Saharian considered how next-generation particle accelerations could produce Standard Model fields that could adjust the density.
Their calculations showed that it could be done with a negative vacuum energy density equivalent to the size of Jupiter. This energy requirement is beyond what we can currently accomplish. The warp bubble has an energy requirement, but Dr. White found that reconsidering it would further reduce that requirement.
He explained that a thicker warp shell would reduce the strain on spacetime and allow for speeds of up to 10 times the speed of light.
“I went through the process and showed that allowing the shell of the warp bubble to get thicker reduces the magnitude of the York time field. Think of that as the strain that you put on spacetime. And so, by making the warp bubble thicker, you could reduce the magnitude of the York time [field]. And it’s non-linear. And so, by doing that, we were able to reduce the amount of exotic matter from Jupiter down to two metric tons – about the size of the Voyager 1 spacecraft.”
Dr. White concluded that the Alcubierre Warp Drive was plausible based on the findings of his seminal paper. It is still necessary for scientists to find a way to generate negative vacuum energy, which will require a breakthrough in physics.
Dr. White and his colleagues at NASA looked into the possibility of achieving this breakthrough at NASA Eagleworks. The Limitless Space Institute is a non-profit organization dedicated to developing the science and technology that will allow humanity to go incredibly fast.
Brian K. founded the LSI in 2020. Kelly was the former Director of Flight Operations at NASA. The non-profit was founded to advance human space exploration beyond the Solar System by the end of the 21st century. The LSI is committed to education and outreach efforts that will inspire the next generation and the research and development of enabling technologies.
Kelly turned to his former colleague at the Johnson Space Center, Dr. Harold White, to help realize his vision. After his former colleague reached out to him, Dr. White began his involvement with the Institute.
“He wanted to talk to me about some education outreach topics. In the process of talking with him, he [asked if I would] potentially leave NASA and come help him stand up and define Limitless Space Institute. After a lot of thought and prayer, it just felt like I could be a little bit more effective at trying to make progress in this domain of advanced power and propulsion. So I made the decision to pull the D-ring at the end of 2019 and join the Limitless Space Institute as the Director of Advanced Research and Development.”
Many former astronauts have joined LSI to realize the goal of FTL travel. The Board of Directors consists of Gregory, Ray J, and Johnson. The Space Shuttle Atlantis made its final trip to the International Space Station on July 8th, 2011.
Kam Ghaffarian is the Chairman of the Board, an engineer andentrepreneur who is the co-founder and Executive Chairman of X-energy, and the CEO of the innovation and investment firm IBX. Fans of commercial space will immediately recognize Gwynne Shotwell as the President and Chief Operations Officer of SpaceX, and a member of their Board of Directors.
Dr. White said that the goal of realizing interstellar spaceflight is a tall order.
“When people think of space travel today, they might think of sending human beings back to the surface of the Moon or neat rovers on the surface of Mars doing interesting things. And those are amazing examples of space exploration, but those are all possible using chemical propulsion. If we want to send human beings to the outer Solar System, if we want to get a crew from the Earth to Saturn in 200 days, the amount of energy that’s necessary to make something like that possible is an entire order of magnitude larger than it takes to get a payload from the surface of Earth to Low Earth Orbit.
It is not possible to do long-distance missions in a reasonable amount of time using chemical propulsion. Dr. White says we need to think beyond the realm of known physics for that to happen. He and his colleagues have adopted a research plan that is more advanced than the last one. NASA and other space agencies are investigating for their future exploration goals with the advancement of Nuclear Electric Propulsion.
This concept uses a nuclear reactor to power Hall-effect thrusters, which use ionize gases to create a charged plasma. The benefits of this method include the fact that it is within the realm of known physics and that it has been used by both NASA and the Soviet space programs. NASA's Systems for Nuclear Auxiliary Power 10A (SNAP-10A) nuclear satellite flew in space for 43 days in 1965, after being tested.
The most powerful of the 40 nuclear-electric satellites sent by the Soviets was the TOPAZ-II reactor, which produced 10 kilowatts of electricity. The Nuclear Engine for Rocket Vehicle Application (NERVA), a nuclear thermal propulsion concept was developed by NASA in 1968. This method uses a nuclear reactor to heat hydrogen propellant and the resulting plasma to generate power. This is the only concept that can generate power in the megawatt range, which is absolutely required for crewed missions.
Dr. White and his team are working towards a NEP engine that could generate 2-50 watt power that would allow for rapid transit to the outer Solar System and other locations. It would take a few thousand years for the NEP to get to Proxima Centauri. Dr. White said moving a little bit into the unknown is required to go faster.
This is where the next step in LSI comes into play, which calls for the development of fusion electric propulsion, which is in the 50 to 500 watt range. Dr. White described it.
“[I]nstead of fission and uranium, we’re using deuterium and tritium or some combination of gases that we could fuse of very high temperatures when they’re in the form of a plasma. Fusion propulsion is a little more capable than nuclear-electric propulsion. The one caveat is [that] we don’t have fusion reactors all over the planet. So the engineering of a fusion reactor, we still have to work that out. But that may actually be a little closer than most people think.
“But fusion propulsion would enable us to send large payloads to Proxima Centauri in 100 years. Maybe less, if you want to get aggressive with the delta-v (acceleration). But if we want to do an interstellar mission to Proxima Centauri, and we want to get there in 20 years or less, that’s where we have to look to the frontiers of physics – move firmly into the unknown.”
Significant progress needs to be made in our understanding of physics if we are to move forward in the third step. We need to find an answer to how the four fundamental forces fit together. This includes how gravity governs interactions on a large scale and quantum mechanics, which describes how matter behaves on the smallest scales.
We need a Theory of Everything, a theory of quantum gravity, which has been elusive for about a century. Dr. White and LSI are taking anIncremental approach that includes future innovations and discoveries. Dr. White said that the introduction of artificial intelligence, machine learning, and advanced computing may be coming sooner than expected. There is a lot of research to be done in the realm of known physics.
Dr. White and his colleagues are studying custom Casimir cavities, which consist of two plates in a vacuum chamber with pillars in between. These tests aim to measure the quantum vacuum's response to the shapes inside the cavities and the predicted characteristics of them. Dr. White and his team performed work for the Defense Advanced Research Projects Agency, where they used custom cavities to explore the possibility of a vacuum field.
He and his team noticed something completely unexpected while looking at how the vacuum responds to shapes.
“The custom Casimir cavities consist of two plates, and in between the two plates, we have pillars. When we were looking at how the models we have predicted how the quantum vacuum responds to those pillar-plate geometries – when we looked at a two-dimensional section cut of the vacuum energy distribution, it looked like a two-dimensional section cut of the energy density distribution needed for the Alcubierre Warp Metric.
The custom Casimir cavities had lenticular energy distributions in their shape. The Alcubierre Warp Metric requires a toroidal ring of negative vacuum energy density. A different approach was implemented by Dr. White and his team.
He said that they looked at how the quantum vacuum would respond to such a model.
The numerical analysis results were published in a paper in the European Physics Journal C. The general public was told in the paper that an object built with a specific geometry would have a warp bubble. It is a significant precedent and a step in the right direction. The next step is to create an experiment to measure the optical properties of the apparatus.
The work continues. Step-by-step!
LSI has partnerships with other scientific organizations and educational institutions. LSI continues to conduct research and development in the Eagleworks laboratory facilities. The LSI has partnerships with Texas A&M and the Massachusetts Institute of Technology to make devices for their lab experiments.
A grant program was started by the Institute to encourage scientific research that could lead to major breakthrough. The Interstellar Initiatives (I 2 ) grants program awards universities and organizations worldwide for theoretical work and empirical work that helps advance space exploration. The first biannual round of grants and awards took place in 2020. Dr. White said that the Institute would be expanding its focus this year.
“This year, we’re doing our second biannual grant cycle and we’re augmenting the original call to also fund graduate and postdoc fellowships. So that’s a new addition to the 2022-2024 cycle. We have LSI scholarships, where we give undergraduate students scholarships. We have a program called LSI Lab Boosters. That is a program that we started to address K-12 so that’s where we provide small seed awards of 3 to 7k to worthy organizations that work with kids in elementary, middle school, and high school. We also have classes, we commissioned the Institute for Interstellar Studies (I4IS) to do a week-long summer class.”
The focus of last year's summer class was Human Exploration of the Far Solar System and on to the Stars, which provided an overview of the spacecraft systems and technology needed for interstellar flight. The Institute will be holding a series of online events with featured guests that address a wide range of topics, from space medicine and diversity in the space industry to coding and languages.
They have a partnership with Texas A&Ms nuclear engineering department to conduct a detailed white paper study on a portable nuclear reactor that meets the program requirements. Microreactors are being created by the DoD to provide power to forward bases for electrical vessels.
The support LSI has given to its sister institution, Breakthrough Starshot, which is currently investigating directed-energy propulsion to accelerate lightsails to a fraction of the speed of light, is an interesting example. Prof. Philip Lubin is the head of the Experimental Cosmology Group at U.C. Santa Barbara. The group specializes in directed-energy technology, with applications ranging from space exploration to planetary defense against asteroids.
The Interstellar Initiatives grant was part of the inaugural grant cycle of 2020.
Many research and non-profit groups are dedicated to making spaceflight a reality. The British Interplanetary Society (BIS), and their spinoff, the Tau Zero Foundation, are examples. The previous project, called the Breakthrough Starshot, is committed to creating lightsail spaceships that could reach nearby star systems in our lifetimes and confirm if there are any planets there.
The true purpose is to grow humanity as a species and improve our understanding of life and the universe. This will have applications for improving life on Earth, which will emerge much sooner than any FTL concepts. Dr. White, who considers himself a very practical thinker, still has some thoughts on how reaching farther out into space will have implications here at home.
Think about the capability to send human beings to every destination in the Solar System. The concept of scarcity would be changed by having an entire Solar System of materials and resources. If you have a whole Solar System at your disposal, it may change the definition of diamond. In order to allow and facilitate human beings to go throughout all the destinations in our Solar System, we have to have compact light and very energetic forms of power.
The quality of life is directly tied to the amount of power each citizen has. It will mean that planet Earth will be in a different position when it comes to generating and utilizing power. The argument is still the same in a future where we can go incredibly fast within the context of our Solar System or nearby stars. It changes the concept of scarcity and prosperity.
The way it motivates people is perhaps the most important aspect of the attempts to realize FTL. Hope to people today is brought by knowing that the science behind it is sound and that one day we will be able to travel through space. Many people believe that human civilization will not survive the 21st century, despite all the bad news. Many look to space as the solution to our long-term survival.
There is a counter-argument to the idea of fixing Earth first. Reducing our impact and dependence on Earth is a better way to fix it. If the entire Solar System is accessible, and nearby stars can be reached in a matter of years, humanity will have the means to ensure that Earth and our civilization will survive any calamity.
"Earth is the cradle of humanity, but one cannot live in a cradle forever," said the author.
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