Les Johnson

• MS Physics
• Science and Technology Office at National Aeronautics and Space Administration

Continuous, in-situ, multi-point observations along the Sun-Earth line at and inside the Lagrange point L1 (sub-L1) will enable a better understanding of the three-dimensional structure and temporal evolution of heliospheric structures that drive terrestrial space weather. The proposed SWIFT (Space Weather Investigation Frontier) mission will use a...

The Space Weather Investigation Frontier (SWIFT) mission will aim at making major discoveries on the three-dimensional structure and temporal evolution of heliospheric structures that drive space weather. Existing remote-sensing and in-situ observatories are not suited for not suited for resolving multi-scale heliospheric structures and evolutionar...

In this work, trajectory design scenarios for near future solar polar imaging missions lever-aging solar sails are examined. Specifically,investigatation is carried out to explore whether including a Venus flyby can improve the overall mission time of flight compared to a traditional SPI mission architecture. For both the flyby and non-flyby archit...

Solar sails are an enabling technology for stand-alone small-satellite deep-space exploration. However, their always-on nature, combined with the time of flight required for deep-space missions, makes them particularly susceptible to safe mode events. This work extends the expected availability and duty cycle approaches for missed thrust mitigation...

This investigation outlines preliminary trajectory design for NASA’s sail-based Solar Cruiser spacecraft, selected on December 3, 2020, to be a secondary payload launched with the Interstellar Mapping and Acceleration Probe (IMAP) in 2025. Trajectory optimization is carried out to ensure that Solar Cruiser can successfully reach a halo orbit about...

Solar sails are of great promise for space exploration, affording missions that push the limits of the possible. They enable a variety of novel science missions ranging from ultrafast interstellar travel to imaging the poles of the sun—missions that are beyond the reach of current propulsion technology. Here, we describe requirements and challenges...

Low areal density and tailored functionality are key attributes making diffractive films attractive for radiation pressure space applications. This talk will describe recent experimental and theoretical work, and a roadmap for the flat optics community.

Two key NASA strategic documents-Our Dynamic Space Environment: Heliophysics Science and Technology Roadmap for 2014-2033 and 2013 Solar and Space Physics: Science for a Technological Society-contain over a dozen references describing the value of solar sails to enable revolutionary new observational capabilities. Based on these needs, the NASA Mar...

This Special Section of Acta Astronautica contains peer-reviewed papers selected from the contributions of the participants at the Sixth International Conference on Tethers in Space (TiS 2019), held June 12–14, 2019 at Universidad Carlos III de Madrid (UC3M), Spain. TiS 2019 provided continuity to TiS 2016, which was held at The University of Michi...

This work outlines preliminary trajectory design for NASA’s proposed sail-based Solar Cruiser spacecraft, which is a finalist to be a secondary payload launched with the Interstellar Mapping and Acceleration Probe(IMAP) in October 2024. Trajectory optimization is carried out to ensure that Solar Cruiser can successfully reach a halo orbit about a S...

The High Inclination Solar Mission (HISM) is a concept for an out-of-the-ecliptic mission for observing the Sun and the heliosphere. The mission profile is largely based on the Solar Polar Imager concept: initially spiraling in to a 0.48 AU ecliptic orbit, then increasing the orbital inclination at a rate of $\sim 10$ degrees per year, ultimately r...

As one of the secondary payloads on the space launch systems vehicle, the Near-Earth Asteroid (NEA) Scout will demonstrate a low-cost and innovative approach to deep space reconnaissance missions. The main objective is to image and characterize a Near-Earth asteroid. The spacecraft packages a full deep space mission into the volume of a 6U CubeSat....

Powering spacecraft by radiation pressure from solar or laser light, once the province of science fiction, is becoming increasingly practical with advances in photonic technology and the space economy.

The electrostatic solar sail (E-sail) is a propellantless propulsion system that is driven by solar wind ions via electrostatic repulsion on multi-kilometer scale tethers. In a full mission design, the tethers are connected to a central body that are spun up to keep tension on the tethers during flight operations in the interplanetary medium. Throu...

Solar sailing technology has been demonstrated in the space environment over the past decade, in Earth orbit and on an interplanetary trajectory. These technology demonstration missions, along with a forty-year history of conceptual studies and laboratory development, have provided a foundation for a new era of missions where solar sailing provides...

While solar electric propulsion (SEP) is being widely considered for cargo transport to Mars, its value for propelling fast human missions is often viewed as marginal. This conclusion is driven by the high electric power requirement (multi megawatts) of a fast human spacecraft, coupled to the low power density of traditional solar arrays. For these...

The Solar Gravitational Lens (SGL) allows for major brightness amplification ($\sim 10^{11}$ at wavelength of $1~\mu$m) and extreme angular resolution ($\sim10^{-10}$ arcsec) within a narrow field of view. A meter-class telescope, with a modest coronagraph to block solar light with 1e-6 suppression placed in the focal area of the SGL, can image an...

Humans have finally found a way to go to the stars and what they find there may mean our extinction in imminent…

In order to advance our capabilities in space exploration within our solar system over the next several decades, it is necessary to a) understand our science and exploration priorities, b) determine operational requirements, c) assess gaps in technologies necessary to fulfill those requirements, and d) perform the necessary research and development...

In-space propulsion begins where the launch vehicle upper stage leaves off, performing the functions of primary propulsion, reaction control, station keeping, precision pointing, and orbital maneuvering. The main engines used in space provide the primary propulsive force for orbit transfer, planetary trajectories, and extraplanetary landing and asc...

Despite decades of old theoretical foundation and all the efforts of space researchers, until very recently there were surprisingly few attempts to build and fly large solar sails in space. Germany’s Deutschen Zentrum fur Luft-und Raumfahrt (DLR) took particular interest in solar sail technology in the 1990s and fabricated one of the first large-sc...

This chapter describes thoroughly the second sailcraft in these years of efforts for transforming the solar-photon sailing from theory to reality. Once again, NASA is the maker of an historical step in the modern history of Astronautics.

What exactly constitutes a technological breakthrough? A breakthrough is an event that opens unexpected doors and expands horizons. Since JAXA’s IKAROS is the first solar-photon sail deployed in interplanetary space and has demonstrated the sail’s utility in both primary spacecraft propulsion and attitude control, it certainly constitutes a technol...

As these words are composed in 2014, we are in the initial phase of solar-photon-sail operational application. Probably, a good historical analog is the status of the chemical rocket in late 1957. As was then the case with Sputnik 1 and 2 in their relation to the chemical rocket, the utility of small solar sails has been demonstrated by the success...

As part of a larger effort led by the Keck Institute for Space Studies at the California Institute of Technology, the Advanced Concepts Office at NASA's George C. Marshall Space Flight Center conducted a study to assess what low-thrust advanced propulsion system candidates, existing and near term, could deliver a small, Voyager-like satellite to ou...

Affordable and convenient access to electrical power is essential for all spacecraft and is a critical design driver for the next generation of smallsats, including CubeSats, which are currently extremely power limited. The Lightweight Integrated Solar Array (LISA), a concept designed, prototyped, and tested at the NASA Marshall Space Flight Center...

In 2017, NASA plans to launch the Near Earth Asteroid (NEA) Scout, a solar-photon-sail propelled probe to rendezvous with one or more near-Earth asteroids. According to a publication describing early design parameters, the spacecraft mass is 12 kg and the square sail has an area of 83 square meters. This craft, like many other NASA science missions...

The reality of sunlight-based sailing in space began in May 2010, and solar sail technology and science have continued to evolve rapidly through new space missions. Using the power of the Sun's light for regular travel propulsion will be the next major leap forward in our journey to other worlds. This book is the second edition of the fascinating e...

Near-Earth Asteroids (NEAs) are an easily accessible object in Earth's vicinity. Detections of NEAs are expected to grow in the near future, offering increasing target opportunities. As NASA continues to refine its plans to possibly explore these small worlds with human explorers, initial reconnaissance with comparatively inexpensive robotic precur...

What was our planet like in years past? How has our civilization affected Earth and its ecology? Harvesting Space for a Greener Planet, the Second Edition of Paradise Regained: The Regreening of the Earth, begins by discussing these questions, and then generates a scenario for the restoration of Earth. It introduces new and innovative ideas on how...

The PROPEL flight mission concept will demonstrate the safe use of an electrodynamic tether for generating thrust. PROPEL is being designed to be a versatile electrodynamic-tether system for multiple end users and to be flexible with respect to platform. As such, several implementation options are being explored, including a comprehensive mission d...

Intense tempests of celestial origin have blown through the skies of Earth, obliterating landscapes and sending towering tsunami through the oceans. Such events have extinguished vast numbers of living organisms; some of these die-offs have been altered by geological processes into fossils.

Conservation, recycling, more efficient machines, altered lifestyles and new sources of energy are all needed to reduce the growth rate of our greenhouse gas emissions. Unfortunately, the best all of these actions combined can achieve is a reduced rate of emission growth. If humans are truly causing global warming by profligate use of fossil fuels,...

386,000,000,000,000,000,000,000,000 W. By any measure, that is a lot of power, and that is the Sun’s power output every second of every day (Fig. 12.1). To make this number easier to work with, scientists write it as 3.86 × 1026 W, or 386 followed by 24 zeros. The amount of solar energy per second reaching Earth, which is 93 million miles from the...

In this chapter, we review the evolution of life on Earth and attempt to address the issue of how pleasant our planet’s pre-human environment was. But before we begin, it might be helpful to investigate how benign or special early Earth was for the origin and evolution of life. We have learned a lot in the past few decades indicating that just havi...

If you are reading this book, you are most likely a member of the most privileged generation in humanity’s experience. You have a roof over your head—a vast improvement over the lot of many of our ancestors and a significant number of humans today. You have access to good health-care facilities and can count on between 70 and 80 good years.

It is a strange time on Planet Earth. For the first time in humanity’s recorded history, we no longer can feel totally secure in Mother Nature’s “balmy nest.” There are simply too many of us, and we all desire to live well. As far as we know, humanity is the first terrestrial species with the technological power to alter Earth’s global environment...

Gloom and doom is easy to sell. Simply watching the evening news fills one with a sense of what is bad in the world: murder, child abuse, increases in the price of gasoline, water rationing due to drought, tension among nation states arising over a religious or economic disagreement, and so on. Listening to the prognostication of the coming age of...

A technology reference study for a multiple near-Earth object (NEO) Rendezvous mission with solar sailcraft is currently carried out by the authors of this paper. The investigated mission builds on previous concepts, but adopts a strong micro-spacecraft philosophy based on the DLR/ESA Gossamer technology. The main scientific objective of the missio...

A technology reference study for a displaced Lagrange point space weather mission is presented. The mission builds on previous concepts, but adopts a strong micro-spacecraft philosophy to deliver a low mass platform and payload which can be accommodated on the DLR/ESA Gossamer-3 technology demonstration mission. A direct escape from Geostationary T...

Solar Sail Propulsion (SSP) is a high-priority new technology within The National Aeronautics and Space Administration (NASA), and several potential future space missions have been identified that will require SSP. Small and mid-sized technology demonstration missions using solar sails have flown or will soon fly in space. Multiple mission concept...

In Chapter 1, we saw that even a small piece of debris, perhaps something as small as a baseball, traveling at over 8 km/sec can damage or destroy a satellite. It's bad enough that our willful neglect of the space environment over the last 50 years has placed our valuable space assets in harm's way; we now have to consider that someone might intent...

We’ve only been sending craft into space for a little over 50 years. The Earth is 4.5 billion years old. My point? We do not have enough data to know whether the space environment our satellites have experienced since the dawn of the Space Age is normal, a relatively quiet period, or if we're in the middle of a particularly active period for the Su...

Much of the world now depends upon space technology economically, politically, and militarily. Without satellites, many of our factories and distribution systems would break down and our "just in time" inventory systems would at least temporarily stall,interrupting the flow of food, medicines, and commodities to our stores and markets. Without spy...

We’ve put over haH a million pieces of junk in Earth orbit that imperil our use of space now and in the future, so what can we do about it? The answer, surprisingly, is that we can do a great deal should we decide it is worth the effort.

On 8 September 1900, the residents of the island town of Galveston, Texas, knew there was a storm coming. What they didn't know was that the storm was a Category 4 hurricane and that, before the next day was through, over 6,000 residents of this tranquil Texas town would be dead. The hurricane's storm surge was over 15 feet and the highest point on...

Energy, environment, farming, Dllning, land use. All of these areas and more are now inextricably linked to satellite data and would be devastated should that Oow of data stop.

Much of the world now depends upon space technology economically, politically, and militarily. Without satellites, many of our factories and distribution systems would break down and our "just in time" inventory systems would at least temporarily stall,interrupting the flow of food, medicines, and commodities to our stores and markets. Without spy...

If we were to suddenly lose our satellites, then you could immediately say “goodbye” to:

If you need help navigating in a strange city, you are likely to use your Global Positioning System (GPS) receiver. For under $200, you may purchase a fully functional GPS receiver that will help you get safely from Point A to Point B. They are now a standard option in many rental cars. Have you bought a house or some land recently? Chances are tha...

Imagine being hit with a bowling ball moving at 100 km/hr. Now imagine being hit with pea traveling at 7 km/sec (25,200 km/hr). Both impacts would release about the same amount of energy, causing comparable damage. By anyone's definition, this would make it a bad day. When it comes to being hit by a moving object, size matters- but speed matters mo...

The loss of a satellite due to a collision with orbital debris is one thing- an expensive event for sure, but, if it is a rare event, it can be overcome. The loss of a human life in a collision is quite another thing indeed.

Control the high ground and you have a good chance of controlling the outcome of a battle. This fact has been known to soldiers since the earliest days when the high ground was the hilltop upon which communities would build their homes - making them defensible during an attack and affording them with a high probability of seeing the advance of a po...

If we were to suddenly lose all of our satellites, we probably wouldn't have the loss of space science data at the top of our list of immediate concerns. After all, unless you make your living designing, developing, or building satellites or are a scientist whose job it is to analyze the data coming back from a particular space science mission, the...

To understand what the loss of America’s Global Positioning System (GPS) would mean to the military, we need to first understand what it is and why it is used.

Much of the world now depends upon space technology economically, politically, and militarily. Without satellites, many of our factories and distribution systems would break down and our "just in time" inventory systems would at least temporarily stall,interrupting the flow of food, medicines, and commodities to our stores and markets. Without spy...

During the summer of 2010, NASA's Office of Chief Technologist assembled 15 civil service teams to support the creation of a NASA integrated technology roadmap. The Aero-Space Technology Area Roadmap is an integrated set of technology area roadmaps recommending the overall technology investment strategy and prioritization for NASA's technology prog...

How much do we depend on space satellites? Defense, travel, agriculture, weather forecasting, mobile phones and broadband, commerce...the list seems endless. But what would our live be like if the unimaginable happened and, by accident or design, those space assets disappeared? Sky Alert! explores what our world would be like, looking in turn at ar...

Solar Sail propulsion has been validated in space (IKAROS, 2010) and soon several more solar-sail propelled spacecraft will be flown. Using sunlight for spacecraft propulsion is not a new idea. First proposed by Frederick Tsander and Konstantin Tsiolkovsky in the 1920's, NASA's Echo 1 balloon, launched in 1960, was the first spacecraft for which th...

The PROPEL ("Propulsion using Electrodynamics") mission will demonstrate the operation of an electrodynamic tether propulsion system in low Earth orbit and advance its technology readiness level for multiple applications. The PROPEL mission has two primary objectives: first, to demonstrate the capability of electrodynamic tether technology to provi...

Solar sail propulsion for the Earth return stage of a Mars sample return mission could reduce (by 25-50%) the launch mass of the orbiter and decrease cost. Solar Sails are TRL 7/8 as demonstrated by the 2010 flight of the JAXA IKAROS mission.

In the early 2000s, NASA made substantial progress in the development of solar sail propulsion systems for use in robotic science and exploration of the solar system. Two different 20-m solar sail systems were produced. NASA has successfully completed functional vacuum testing in their Glenn Research Center’s Space Power Facility at Plum Brook Stat...

A spaceflight validation of bare electrodynamic tape tether technology was conducted. A S520-25 sounding rocket was launched successfully at 05:00am on 31 August 2010 and successfully deployed 132.6m of tape tether over 120 seconds in a ballistic flight. The electrodynamic performance of the bare tape tether employed as an atmospheric probe was mea...

In the early to mid-2000s, NASA made substantial progress in the development of solar sail propulsion systems. Solar sail propulsion uses the solar radiation pressure exerted by the momentum transfer of reflected photons to generate a net force on a spacecraft. To date, solar sail propulsion systems were designed for large robotic spacecraft. Recen...

Solar sails can play a critical role in enabling solar and heliophysics missions. Solar sail technology within NASA is currently at 80% of TRL-6, suitable for an in-flight technology demonstration. It is conceivable that an initial demonstration could carry scientific payloads that, depending on the type of mission, are commensurate with the goals...

There can be no question that today, one species, Homo sapiens, bestrides the world. In some circles, it is fashionable to lament this situation. Has a Golden Age been lost; has Eden been transformed into an omnipresent global civilization of commerce, popular culture, consumerism, and accumulation? Perhaps, according to some, Earth’s prime is past...

“Gloom and doom” is easy to sell. Simply watching the evening news fills one with a sense of what is bad in the world: murder, child abuse, an increase in the price of gasoline, water rationing due to drought, tension among nation states arising over a religious or economic disagreement, and so on. Listening to the prognostication of the coming age...

As Walt Whitman watched the multitudes commuting between Brooklyn and Manhattan in the days before the construction of the Brooklyn Bridge, he dreamt of the multitude that would make that crossing in the future. He could not have imagined the much larger population that has been born in recent years to challenge the future of Earth.

When people think of the issue of decreasing biodiversity, they generally consider pets, domestic animals, majestic beasts, and useful plants. Although many beasts and plants are threatened (pets and domestic animals are not threatened), the problem runs far deeper.

Walt Whitman was right: Earth is not a closed system. The road to the riches of the solar system lies open. Nature has provided humanity with a virtually unlimited supply of raw materials, and that supply is right above our heads. The asteroids, comets, planets, and moons of the solar system contain enough of the soon-to-be-scarce raw materials req...

Philosophers and theologians have debated what constitutes morality since there have been people around to consider the notion. The word morality comes from Latin and refers to our notion of what constitutes right and wrong or good and evil. What constitutes a moral action varies dramatically from culture to culture, though many cultures share some...

Conservation, recycling, more efficient machines, altered lifestyles, and new sources of energy are all needed to reduce the growth rate of our greenhouse gas emissions. Unfortunately, the best that all of these actions combined can achieve is a reduced rate of emission growth. If humans are truly causing global warming by profligate use of fossil...

In the late 1990s, the author Frank White visted Huntsville, Alabama, and lectured at the local university on what he called the “overview effect.” White had just authored a book by that title and was touring the country speaking on the subject and promoting his book. According to White, most of the world’s astronauts experience an epiphany when th...

All of us have experienced the darkness and felt despair. Our civilization’s problems seem beyond measure—an exploding population, pollution, energy shortages, climate change, terrorism, and nuclear proliferation are among those threats. There is nowhere in space to flee to; Earth is filled up, the moon may be waterless, Mars is a lifeless desert,...

The Advanced X-ray Timing Array (AXTAR) is a mission concept for X-ray timing of compact objects that combines very large collecting area, broadband spectral coverage, high time resolution, highly flexible scheduling, and an ability to respond promptly to time-critical targets of opportunity. It is optimized for submillisecond timing of bright Gala...

In the beginning, a cloud composed mainly of hydrogen and helium gas drifted through the interstellar void. Near or within this immense nebula (it must have been trillions of miles across), a bright star blazed. Much larger and more massive than our present-day sun, this nameless star approached the end of its life cycle about 5 billion years ago....

As we have seen, the distant past was difficult for the ancestors of man. But where have the development of civilization, the agricultural revolution, the art of metallurgy, and the scientific revolution left us? We seem to be suspended from an environmental cliff. We cannot hang on, but we are doomed if we let go!KeywordsHeat EngineGlobal Civiliza...

The thought is not new, but it is profound and it can help guide humanity as we deal with the myriad environmental challenges facing us at the beginning of the 21st century: we all inhabit one giant spaceship on a voyage together through the dark emptiness of space. We call it “Spaceship Earth.”

As mentioned in Chapter 3, the immutable laws of thermodynamics appear to place a limit on how well we can be stewards of our planet. To recap, the first law states that all energy is conserved. This means that no matter what you do, you cannot get more energy out of a system than you put into it. And some of that energy is inevitably wasted, which...

These articles are alarming. They warn that Earth is getting warmer and changes in the global climate are inevitable. The evidence of a global change in climate is mounting and the consensus is that humans are responsible through our profligate emission of so-called greenhouse gases. The authors of this book are not climatologists and are therefore...

What was our planet like before the advent of our modern civilization? What effect has our civilization had on the planet and its ecology? Paradise Regained begins by discussing these questions and then generates a scenario for the re-greening of Earth. It introduces new and innovative ideas on how humankind could use the resources of the Solar Sys...

An overview of a sounding rocket, S-520-25th, project on space tether technology experiment is presented. The project is prepared by an international research group consisting of Japanese, European, American, and Australian researchers. The sounding rocket will be assembled by the ISAS/JAXA and will be launched in the summer of 2009. The sounding r...

Sailcraft offer unique opportunities to space-mission planners. Some of these possibilities will be exploited in the near future, others within a few decades, and some in the more distant future. We consider near-term mission possibilities first.

At this point in its development, the solar sail can be characterized as fairly late in its theoretical phase and fairly early in its developmental phase. It is probably equivalent to the chemical rocket in 1930, the automobile in 1900, and the heavier-than-air aircraft in 1910.

We are nearing the end of this introductory book on solar sailing. We saved one of the most intriguing topics—trajectory design—for last. However, it is beyond the scope of this book to delve deeply into mathematics and the related physical aspects. So after a very short presentation of the sailcraft motion equations, we discuss the class of trajec...

There has not been a robotic lander on the surface of the moon since the American Surveyor and the Soviet Luna Programs of the late 1960's and early-to-mid 1970's. Many national space agencies and even some private companies are considering resumption of robotic lunar surface exploration in advance of the anticipated return of humans to the moon so...

Despite its decades old theoretical foundation and all the efforts of space researchers, there have been surprisingly few attempts to build and fly large solar sails in space. Germany’s DLR took particular interest in solar sail technology in the 1990s and fabricated one of the first large-scale ground-based engineering model sails. The Russians de...