The major shortcoming of current chemical powered rockets lies in the ratio of payload to fuel. The dream of rocketeers would have a spacecraft almost all payload. Leik Myrabo and John Lewis have an idea for this and they present it in the book “Lightcraft – Flight Handbook LTI-20 “. Within the book lies great detail on a special flying craft and some of its essential subsystems.
This book aims to extol the virtues of a large craft that relies upon microwaves to transfer energy from one location to itself. Via this, the craft need not carry any significant power supply, though the book does mention backup batteries. Further, the book describes, with great relish, the use of ionizers that create the thrust and provide the flight control. Though perhaps sounding farfetched, one author, Leik Myrabo, is recognized as being a worldwide expert in this field and he has undertaken trials on laser launched vehicles. From this, the book has an authoritative ring.
Now the book’s subject does sound very futuristic. And the book’s layout acknowledges this by being written as a flight handbook for travellers in the year 2025. That is, if you were to take a ride on the LTI-20 laser powered craft, then you would need to know the contents of the book so as to understand the craft’s functionality. Hence, the result for the reader is a book that smacks whole heartedly of science fiction even though practical research has taken place.
So here’s your dilemma regarding this book. Do you buy it for the fun science fiction or do you buy it because of the novel method of power supply and flight control. If you want both, then you are in luck. If you like science fiction technology, such as headgear for partial liquid ventilation, this book has lots, but it’s very disjointed and most topics are unsubstantiated. If you want to know more about laser power, this book has the details, but at the level of an article for Popular Mechanics. And sadly, the connection between the future described within the book and current research is tenuous at best. Hence, this book, while entertaining, lacks from a practical stand point.
Nevertheless, there is no mistaking the potential of microwaves to transfer energy to flying craft as described within. As well, ionizers should provide effective flight control, at least while a sufficient quantity of atoms exist (i.e. this won’t work in space). So, for the pleasure of reading about cutting edge technology then Leik Myrabo and John Lewis’ book “Lightcraft – Flight Handbook LTI-20 ” is for you.
When it comes to exploring the hostile environment of space, robots have done a lot (if not most) of the exploring. The only other planet besides Earth that humans have set foot on is the Moon. Robotic explorers, however, have set down on the Moon, Mars, Venus, Titan and Jupiter, as well as a few comets and asteroids. Robotic missions can travel further and faster, and can return more scientific data than missions that include humans. There is much debate on whether the future of space exploration should rely solely on robots, or whether humans should have a role.
As contentious as this issue is, there is no doubt that robots have and will continue to contribute to our understanding of the Universe. Here’s a short list of past, current, and future robotic missions that have done or will do much in the way of exploration of our cosmos.
The most famous robots in space have to be the series of orbiters, rovers and landers that have been sent to Mars. The first orbiter was Mariner 4, which flew past Mars on July 14, 1965 and took the first close up photos of another planet. The first landers were the Viking landers. Viking 1 landed July 20, 1976, and Viking 2 on September 3, 1976. Both landers were accompanied by orbiters that took photos and scientific data from above the planet. The landers included instruments to detect for life on the surface of Mars, but the data they returned is somewhat ambiguous, and the question of whether there is life on Mars still requires an answer. Currently, Spirit and Opportunity are roving away on the Martian surface, well past their expected mission lifetime, and the Phoenix lander returned a wealth of information about our neighbor. For more about the entire series of Mars missions, go to NASA’s Mars Exploration Program website. Of course, NASA isn’t the only space organization represented at Mars – the European Space Agency currently has Mars Express orbiting the planet, and has the first webcam of another planet available!
Mars isn’t the only place to go in the Solar System, though. Both the U.S. and the Russians sent numerous missions to Venus, with a lot of successes and failures. For a complete list of the many missions to Venus visit the Planetary Society. The most notable firsts are: Mariner 2 was the first successful Venus flyby on December 14, 1962, and the Russian lander Venera 7 was the first human-made vehicle to successfully land on another planet and transmit data back to Earth on December 14, 1962.
Sputnik 1, of course, was the first robot in space, and was launched October 4th, 1957 by the USSR.
The Voyager missions are notable for the milestone of having a robot leave the Solar System. Voyager 1 and 2 were launched in 1977 are still making their way out of the Solar System, and have entered the heliopause, where the solar wind starts to drop off, and the interstellar wind picks up. To keep up with their status, visit the weekly status page.
Dextre, a robotic arm developed by the Canadian Space Association, is a very cool robot aboard the International Space Station. Dexter allows for delicate manipulation of objects outside the station, reducing the number of space walks and increasing the ability of the ISS crew to maintain and upgrade the station.
This is by no means an exhaustive list of the enormous number of robotic space missions. To learn a lot, lot more check out the Astronomy Cast episode on Robots in Space, the ESA robotics page, NASA missions page, and the Planetary Society missions page.
Have you ever noticed that astronauts float around in the space shuttle and in the International Space Station, while space travelers on television and in the movies keep their feet firmly on the ground. That’s because it would be very difficult (and expensive) to have your actors floating around in every scene. So science fiction writers invent some kind of artificial gravity technology, to keep everyone standing on the ground.
Of course, there’s no technology that will actually generate gravity in a spaceship. Gravity only comes from massive object, and there’s no way to cancel the acceleration of gravity. And so if you wanted to have a spacecraft that could generate enough artificial gravity to keep someone’s feet on the ground, the spaceship would need to have the mass of the Earth.
Floating in space is actually very hard on astronauts’ bodies. The lack of gravity softens their bones and causes their muscles to weaken. After any long trip into space, astronauts need several days and even weeks to recover from traveling in microgravity.
But there a couple of ways you could create artificial gravity in a spaceship. The force we feel from gravity is actually our acceleration towards a massive body. We’d keep falling, but the ground is pushing against us, so we stand on the ground. If you can provide an alternative form of acceleration, it would feel like gravity, and provide the same benefits of standing on the surface of a planet.
The first way would be through accelerating your spaceship. Imagine you wanted to fly your spaceship from Earth to Alpha Centauri. You could fire your rockets behind the spacecraft, accelerating at a smooth rate of 9.8 meters/second2. As long as the rocket continued accelerating, it would feel like you were standing on Earth. Once the rocket reached the halfway point of its journey, it would turn around and decelerate at the same rate, and once again, you would feel the force of gravity. Of course, it takes an enormous amount of fuel to accelerate and decelerate like this, so we can consider that pretty much impossible.
A second way to create acceleration is to fake it through with some kind of rotation. Imagine if your spaceship was built like a big donut, and you set it spinning. People standing on the inside hull would feel the force of gravity. That’s because the spinning causes a centrifugal force that wants to throw the astronauts out into space. But the spaceship’s hull is keeping them from flying away. This is another way to create artificial gravity.
There are no spacecraft that use any form of artificial gravity today, but if humans do more space exploration, we will likely see the rotational method used in the future.
Navigating a spacecraft through the heavens has been compared to sailing a ship on the open seas or driving a vehicle on a long, cross country journey. Analogies are necessary, since spacecraft navigation is performed by a relatively small sampling of the human race, and the job usually involves doing things that have never been done before. Those of us who have trouble making sense of a road map here on Earth stand in awe of what these celestial navigators can accomplish.
Literally, this is rocket science.
In simplest terms, spacecraft navigation entails determining where the spacecraft is and keeping it on course to the desired destination. But it’s not as easy as just getting from Point A (Earth) to Point B (a planet or other body in our solar system.) These are not fixed positions in space. Navigators must meet the challenges of calculating the exact speeds and orientations of a rotating Earth, a rotating target destination, as well as a moving spacecraft, while all are simultaneously traveling in their own orbits around the Sun.
Chris Potts, who helped lead the navigation teams for the Mars Exploration Rovers (MER), compared the target requirements of landing the Spirit rover inside a specific crater on Mars to being able to shoot a basketball through a hoop 9000 miles away. “Not only do you have to make the shot perfectly without the ball touching the rim, but the timing has to be perfect, so you make the shot exactly as the buzzer sounds,” he said.
Ken Williams was the Navigation Team Chief for the Stardust mission’s return of pristine samples of a comet back to Earth. For a successful re-entry and landing at a precise location in Utah, the navigation team had to target the return capsule’s entry to a specific point in the Earth’s atmosphere to within eight 100ths of a degree, a feat that’s been compared to hitting the eye of a sewing needle with a piece of thread from across a room.
Navigation is essential to every robotic mission, and while mission success hinges on how well the navigation team performs, navigators aren’t usually found in the limelight, sitting up on stage for a press conference. Typically that’s reserved for the mission scientists and designers. The navigators, seemingly, work behind the scenes, manning the trenches in relative anonymity.
But I had the opportunity to talk to a few spacecraft navigators, learning more about their job and discovering the innate qualities of those who guide our spacecraft to places beyond.
Neil Mottinger has been part of numerous missions since he started working at the Jet Propulsion Laboratory in 1967. He assisted with some of the early lunar and planetary missions, and developed some of the software that navigators still use today.
There are several different sub-disciplines to spacecraft navigation, and one of Mottinger’s specialties is orbit determination. “Orbit determination is knowing where the spacecraft is and where it’s going,” said Mottinger, who currently works with the Mars Reconnaissance Orbiter (MRO) mission and the upcoming LCROSS (Lunar Crater Observation and Sensing Satellite) mission to the moon. “It starts with predicting the trajectory where the spacecraft will be immediately after launch so that the Deep Space Network (DSN) knows where to point their antenna and on what frequency to expect the signal.” The DSN consists of a network of extremely sensitive deep space communications antennas at three locations: Goldstone, California; Madrid, Spain; and Canberra, Australia. The strategic placement approximately 120 degrees apart on Earth’s surface allows constant observation of spacecraft as the Earth rotates.
Since there’s no GPS in outer space, navigators process the radiometric tracking data received from the DSN to determine the spacecraft’s position and velocity. They also use optical data, where the spacecraft takes a picture of the star background to help refine the spacecraft’s trajectory.
For many years, Mottinger worked with a group that provided navigation support for the launch of over 100 spacecraft. “I never got attached to any one mission since right after a launch we moved on the next mission,” Mottinger said. But now he stays with missions longer and has been with the MRO mission for the better part of three years. Mottinger is thrilled with the scientific data this mission has returned. “We have to provide accurate predictions of where the spacecraft is going to be. Then the engineers know how to orient spacecraft so that the scientists can make their observations,” he said. “If we do our job, the scientists can see a landslide on Mars or look at specific areas on the planet. If our predictions are wrong, the cameras are pointed in the wrong direction. Navigation is integral to the whole process of ensuring mission success.”
Mottinger said that typically one doesn’t think of navigators as scientists, only as a means to an end for the scientists to get results. However, sometimes scientific by-products come from navigation. The most famous instance involved the Voyager mission when navigator Linda Morabito discovered a volcano on Jupiter’s moon Io from looking at optical navigation images. In the Lunar Orbiter missions, navigators realized there were large concentrations of mass, (now called mascons) underneath the moon’s surface that were accelerating spacecraft in orbit.
Additionally, the science used in navigation has improved dramatically over the years. “When you look at the types of things we didn’t understand when I first started versus what we know now, it’s overwhelming,” said Mottinger. For example navigators can now create very accurate models of solar pressure – how particles of sunlight push against a spacecraft and alter its trajectory — which includes not only how sunlight is reflected from different surfaces of the spacecraft, but also the re-radiation of energy absorbed by the solar panels and radiated out the back side.
Additionally ephemerides, the tables navigators use to obtain the positions of astronomical objects, have also improved in accuracy over the years. “The devil is in the details,” said Mottinger. “Navigation is getting to be an incredibly precise game.”
Like many who work at JPL, Mottinger enjoys talking to schools or community groups to share the excitement and recent discoveries of space exploration. “It’s important to be out there telling our message to get people excited about what we’re doing,” he said. “And the public is entitled to be excited, because they’re paying the bill.”
Several years ago Mottinger returned to his hometown of Oswego, Illinois to talk to students about his job as a navigator. Sitting in the classroom was a young Chris Potts, who decided spacecraft navigation was the career he wanted to pursue. Potts, who has been at JPL since 1984, was the Deputy Navigation Team Chief for MER and now works with the Dawn Mission that is en route to orbit two asteroids, Ceres and Vesta.
Potts’ specialty is flight path control. This involves firing the propulsion system to alter the spacecraft’s velocity or trajectory, known as Trajectory Correction Maneuvers (TCM). “That includes understanding the spacecraft’s control capabilities and determining any limitations,” said Potts. “You determine when you’re going to fire the propulsion system, how often and the objective of each maneuver. You also have to evaluate the delivery requirements, to make sure you can land within a crater on Mars, for example, and minimize risk along the way.”
The design aspect is Potts’ favorite part of the job. “You try to develop a strategy that puts all the pieces together,” he said. “You have to talk with the mission scientists and understand what their requirements are, and then know what the spacecraft can do. It’s like people who have an old car and they’ve been around it so long, they know how to get the most out of that vehicle. Taking advantage of what the spacecraft does well and working around its limitations feeds into the design of a strategy that pulls it all together to make it work.”
Much of Potts’ work involves simulations and testing. “We see how the spacecraft behaves, and try out different strategies to improve it for our situation,” he said. “The navigation section has a whole ‘toolbox’ of software that we’re able to use.”
The Dawn spacecraft uses an ion engine, and this is the first time Potts has worked with a low thrust propulsion system. “It’s quite a different mission,” he said. “The concerns are little bit different than other missions because the thrust is so efficient. One of the things you worry about is not having enough time to make any corrections that are needed. Although the thrust is low, over time it builds up quite a velocity change and you’re always designing trajectories and changing commands to make sure the ion engine is firing in the right direction. If there’s any kind of spacecraft fault or hiccup along the way, you have to scramble, and some future events might have to be moved around.” Dawn will arrive at Vesta in 2011.
Potts enjoys being part of the excitement of all the different missions at JPL. “I really enjoy working with some extremely intelligent and talented people here and you can definitely sense the passion for the work that they do,” he said. “Sometimes that can be intimidating, but you realize that everyone has their own talent to offer, and everyone helps drive you to do your best here. We get to do a variety of interesting work, and it’s very challenging. No two days are the same.”
One of the rewards of his job, Potts said, is seeing the fruition of his work come to light in scientific discoveries. “With the Stardust sample return, to watch the capsule land right where it was supposed to in Utah was very rewarding,” he said. “And to see the scientists get their hands on that data and start to perform their investigations, you sense how thrilled and excited they are to finally get to work on their lifelong ambition.”
Potts and Mottinger both worked on the Stardust mission under the leadership of Ken Williams. Williams worked at JPL for several years, but currently is employed by KinetX, a private engineering firm specializing in aerospace technology and software development. At present, KinetX provides navigation support for the New Horizons mission to Pluto, as well as the MESSENGER (Mercury Surface Space Environment Geochemistry and Ranging) mission to Mercury, and Williams is MESSENGER’s navigation team chief. Unlike Mottinger and Potts, Williams hasn’t always been involved in space missions and his career in navigation evolved from a background in physics. He worked at the Applied Physics Lab at Johns Hopkins University before coming to work at JPL in 1994.
Williams’ favorite part of being a navigator is finding and solving interesting technical problems. “That’s what gets my interest,” he said. “MESSENGER certainly has a number of those. We flew by Earth once, Venus twice and Mercury twice. We’ll have to fly by Mercury one more time before we finally go into orbit on the fourth encounter. Finding a trajectory that does all those things successfully is a very interesting technical problem that I’m very glad to be involved with. We have to consider all sorts of constraints, too, such as keeping the spacecraft pointed away from the sun so that the components don’t get too warm.”
As a Navigation Team Chief, Williams coordinates all the sub-disciplines of orbit determination, flight path control, and optical navigation along with the needs of mission scientists in terms of observations when they encounter a planet or comet.
Williams, too, enjoys the exhilaration of being in the thick of the action in important space missions. “I suppose it’s like being in a battle, or in a basketball or football game,” he said. “You feel the excitement of seeing events unfold, and responding to any anomalies or surprises that come up. And when it’s all done you have a tremendous sense of satisfaction.”
His experiences with Stardust’s return to Earth stand out as a highlight. “Getting all that effort coordinated and getting the spacecraft down successfully was probably the single most rewarding experience in all the time I was at JPL,” he said. “On nearly every mission I’ve worked on there has been a time where you have a sense of euphoria about having the spacecraft be in the right place at the right time. That’s a good feeling to have.”
Although leaving JPL was a difficult decision, Williams enjoys his experiences at a private company. “It would have been easy to stay at JPL and be what they call a ‘greybeard’ in terms of having experience, but after Stardust, I liked the challenge of leading a navigation team and growing in technical areas,” he said. “I thought there would be a better opportunity to do that with a small team in a small company, and I thought KinetX was a good place to accomplish that.“
Quite the opposite of a ‘greybeard’ is navigator Emily Gist. She has been at JPL for 4 years and is part of the navigation team for the Cassini mission at Saturn. Like Potts, she works in flight path control, helping to plan the trajectory and estimate the future position of the spacecraft, and to control the corrections required to achieve the mission objectives.
She takes great satisfaction knowing she is helping to facilitate exploration. “The Saturnian system is more beautiful than most would have imagined and more diverse than previously known,” she said. “The information Cassini has provided has enlightened us all. More specifically I love how much I learn each and every day at JPL and working on the Cassini Mission.”
As part of the ‘next generation’ of navigators, Gist enjoys the challenging environment that JPL provides. “We had an Operations Readiness Test on Cassini where the team was tested to see how we would react to a failure or fault on the spacecraft in an operational environment,” she said. “The senior engineers weren’t in play so the newer generation had to figure it out on our own and we did an excellent job. It made me proud of all the folks I work with. They are truly talented people.”
Gist said gender has never been an issue in her job as a navigator. “JPL has a wonderfully diverse staff and while there are not very many female navigators we are not treated differently,” she said. “I am pretty biased, but I think what we lack in quantity we make up for in quality. I work with some amazing women.”
“Additionally, I feel fortunate to live in a time and society where regardless of gender one can find the thing they want to do and do it to the best of their ability. I love being an engineer and what I try to convey to young women is that they can love anything they want, even if it’s math and science, without fear that it’s a less feminine job.”
The hardest question for all the navigators to answer was if they had a least favorite part of the job. They cited the usual problems with any job: not enough time and too much paperwork. And stress comes with the job. “Deadlines, especially working at JPL, are very real,” said Potts. “If you’re not prepared for a critical event in the mission, you usually don’t get a second chance. There’s a lot riding on getting your job done properly.”
But all the navigators emphasized the importance of the team aspect in their job. “You look for the inherent quality of the team,” said Mottinger. “I had a project manager who said that a team catches each other’s mistakes and the whole is greater than the sum of the parts. Everything is done in a spirit of camaraderie, and there’s no such thing as a stupid question.”
But seeking individual limelight just doesn’t seem to be in a navigator’s makeup.
“I’m more comfortable working behind the scenes than doing an interview,” said Potts. “When I know I’ve done my job, and contributed to the mission success, that’s enough for me.”
“I am fine with my work being behind the scenes,” added Gist. “However when I consider the work the engineers before me and around me have done I sometimes feel they should get more recognition.”
Williams feels, in general, the field of navigation itself should get more recognition. “I think scientists and people who do purely hardware systems underestimate the difficulty of what navigators have to do,” he said. “It would be nice if we got more recognition from our peers just from the standpoint of being able to influence how missions are planned and designed to begin with so that navigation issues can be addressed before launch and not only left for us to deal with after launch. I feel more strongly about that than any recognition of my own accomplishments.”
Williams said that what navigators do is more of an art form. “It’s not reducible to a set of algorithms that can be stored on board a flight system like power or propulsion, for example. It’s constant refining.”
And are navigators bothered by the sometimes long and odd hours their job requires? “No,” said Mottinger, “I wouldn’t trade it for anything. There’s nothing else like it.”
Even before man had managed to take to the skies on our planet, he had thought of spaceflight and soaring through the skies of the planets that he could see. As soon as the Montgolfier brothers had successfully launched their first hot air balloon a race began to see who could fly untethered, then into space. That race for spaceflight never let up. Yuri Gagarin and the Soviet space program arrived first, but the Americans were close behind and were committed to one-up-manship.
Tackling all of the spaceflight articles on the internet would take a dozen researchers a lifetime. Of course, you do not have that kind of time or patience, so we have assembled links to all of the articles that we have here on Universe Today related to the topic. We do not expect you to just dive in blind, so here are a few fun facts about spaceflight.
The average space suit costs a little over $12 million(U.S.). Not bad for an outfit that can protect you from a meteorite.
There are 13,000 detectable pieces of space junk…left over pieces and parts from space repairs, broken down satellites, etc. Where ever man goes, garbage seems to accumulate. Some of this junk managed to destroy at least one satellite.
We are on the cusp of full blown space tourism. The ultrarich have been buying trips on space shuttle missions for years, but there are at least two companies that have tested commercial spacecraft.
Many of today’s modern rockets are a variation of the German V2 rocket.
There are hundreds of interesting facts about spaceflight in the links below. Everything from space food to space tourism and the different mission launched by various space agencies. Hopefully, you will find everything that you need and, as always, enjoy your research.