My kind of spaceship

You’re about to head for a journey through our Solar System and beyond. What fictional spaceship would you like to board? Would it be Millenium Falcon, Battlestar Galactica, USS Enterprise or something completely different?
Nancy Atkinson (Editor at Universe Today, writer for Seeker and author of “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos”)

I would like to travel on board a Nova-class starship, which was a type of Federation starship in Star Trek designed for short-term planetary research missions. Instead of studying other worlds from far-away Earth, why not go visit them and study them in situ? Strange new worlds indeed! I might have to wait a while to do this though, as in Star Trek lore, these type of ships will only be placed in service starting in the late 24th century.

Paul Carr (Space Systems engineer at NASA, podcaster, blogger, investigator)

Based purely on sentiment, it would be Serenity, which strikes me as being in spirit much more like a long range spaceship than luxury liners like the Enterprise. That said, all the science fiction spaceships I’ve come across take considerable liberties with physics, astronomy, or both. Douglas Adams’ Heart of Gold gets around all these bothersome realities by exploiting infinite improbability, but that is more unlikely to come about than a Babel Fish.

One fictional spaceship that minimizes these little white lies is Arthur C. Clarke’s Discovery One from 2001 a Space Odyssey. No magical artificial gravity, impossible propulsion, or unnecessary bulk. Of course, you would never get out of the solar system with such a craft.

In the far future, I would envision relatively small interplanetary craft powered by small black holes, with the shielding problems largely solved to allow travel at large fractions of the speed of light. There would be biological organisms aboard such a craft (apart from some hitchhiking bacteria), just uploaded minds that construct for themselves a new, properly adaptive body upon arrival at a destination. Daniel Cartin’s simulations show that you could build a network of colonies in the local solar neighborhood with an 11 parsec range, which seems just doable to a 21st century engineer.

Ciro Villa (technologist, application developer, STEM communicator)

“The Avalon” of the movie “Passengers” is absolutely breathtaking. I wouldn’t mind cruising the Galaxy on that one.

Fraser Cain (publisher at Universetoday.com, co-host of Astronomy Cast)

Personally, I’ve always preferred the Stargate method of travel, using wormholes to voyage from world to world. What could be more convenient and civilized than to walk through a Einstein-Rosen Bridge and arrive at your destination. That’s the only way to go.

Seth Shostak (Senior Astronomer and Director of the Center for SETI Research at SETI Institute)

Enterprise, of course. I like the never-iron uniforms.

Bob Novella (co-founder and vice-president of New England Skeptical Society, co-host of Skeptics’ Guide to the Universe)

Many spaceships in science fiction would do a fine job touring our solar system. Using their Warp or Hyper or U-Space drives, they could visit all planets and even the Oort Cloud a light year away between breakfast and lunch, assuming you preferred just a 3 hour tour 🙂

For the deluxe tour, though, I’d have to take advantage of Time and Relative Dimension in Space, otherwise known as the TARDIS from Dr. Who. This wonderful vessel could of course flit between planets faster than any other vessel… more importantly though, it could turn each planetary visit into a tour de force of our solar system’s evolution.

You could visit each planet and see it evolve from its birth billions of years ago all the way to its ultimate demise: burned to a crisp as the sun dies, dismantled and used as a Dyson swarm component, or if it survives all that, you could discover if it crashes into the sun due to the loss of gravitational wave energy in a quintillion or sextillion years.

When the the tour is done, you could then choose to return a nanosecond after you left. I can’t think of any other ship in science fiction that could do so much in so little objective time (except maybe the Heart of Gold, but I wouldn’t want to see any whales crashing into planets)

To infinity and beyond!

Elon Musk has sent his cherry Tesla Roadster on a Falcon Heavy maiden flight. If it was up to you, what would you send as a payload on that flight and where would it be going?
Mike Simmons (Founder and CEO of “Astronomers without Borders”)

What would I send as a payload? Me! Driving a Tesla roadster would be good but it seems to offer little protection.

Seriously, the payload wouldn’t have made any difference on the test flight. No one was going to risk a valuable scientific payload on an unproven rocket, especially when the builder says it has only a 50% chance of success. I think the proof of concept for the Falcon Heavy’s ability was quite successful.

At first it seemed more than frivolous to send his car into orbit around the Sun. But after seeing the images sent back from it and looking at the attention it got I really like it. The launch is an incredible feat and this quirky way of doing it was just mind-bending. Something different in an era where rocket launches and satellites are becoming routine.

Nancy Atkinson (Senior Editor for Universe Today, Host of the NASA Lunar Science Institute podcast & a NASA/JPL Solar System Ambassador)

I would have loved for SpaceX to include student experiments or some payload chosen by young people. I think that would have been the most altruistic, educational and scientific choice. But if I understand the story correctly, SpaceX had asked NASA and the US Air Force if they were interested in sending a scientific payload, free of charge on the Falcon Heavy. And while I’m not sure about the timing, but I’m betting there was a delay in a response from NASA and the Air Force, and after the answer was no, that left SpaceX to choose something fairly quickly. There may not have been time to develop something like a competition for student experiments. But the live video feed of the Tesla Roadster in orbit of Earth may have been one of the most exciting, inspirational and just plain cool things that kids have seen lately in regards to space exploration, so perhaps the Tesla was the perfect choice.

Paul Carr (Space Systems engineer at NASA, podcaster, blogger, investigator)

I am amused and disappointed at all the noise over Elon Musk’s choice of a dummy payload – his own car. I thought it was very touching and completely appropriate (full disclosure, I am a Tesla shareholder).

It is impossible to tell payload provider before a demonstration launch that their satellite is not at high risk on an unproven rocket. Throughout the long process leading up to the launch, SpaceX had been managing expectations. They have a history of failing early and learning from it. They felt they had all the known unknowns under control, but in a complex system, it is the unknown unknowns that can easily cause a disaster. I have no doubt that SpaceX approached, or were approached by, a a number of entities about having their payload on the demo flight, but all had to accept the risk. It is easy (and lazy) to say that a scientific payload should have flown, but only in hindsight is this possible, and so the word “should” has to be replaced with “could”. As it is, I think Starman was a master stroke of public relations that no one will forget for a long time. The “Don’t Panic!” sign on the dashboard made it perfect for me. I believe Douglas Adams would have been delighted to see that.

If I had about $20 million sitting around idle, and had been approached by SpaceX, I would have offered an infrared telescope to be positioned at one of the Earth-Moon Lagrange points (probably L1, most of the way to the moon from the Earth) to look for temporary moons. These are small asteroids that are captured into the Earth-Moon system, stay for a few orbits, and then get flung back out into the solar system. At present, we discover them pretty much by luck, if int all. A more systematic survey would provide a more accurate census of these objects, and other Near Earth objects as well. Flying all the way to a Lagrange point before the injection burn might have been a strain on the rocket’s batteries, but will put that in the bucket of solvable engineering problems. The relight of the upper stage after a days long cruise would be an even better demo than what they got.

My ultimate goal would be to have a squadron of probes ready to shoot out after the temporary moons, and intercept and rendezvous with them to ascertain their mineralogy and ore-bearing potential at close distance. This would be more elaborate and expensive, but the first baby step of a telescope to detect the moons might be worth risking on a demo mission.

Antonio Paris (Astronaut Candidate, Astronomy Professor, Planetary Scientist, Space Science Author)

If I had the opportunity to select the payload for the Falcon Heavy test flight, I would have to admit that the rocket would not be powerful enough. The rocket would have been loaded with an assortment of trinkets that represented all of humanity, such as music and photos from diverse cultures. Now do not get me wrong – a Telsa Roadster is pretty cool. However, a sport car does not represent humanity in a nutshell, but rather it only represented Elon Musk and a select class of citizens most of us will never hold membership in.

Prepare for warp speed

Science fiction has shown us spaceships travelling at enormous speeds, some of them had faster-then-light capabilities (and some have done the Kessel run in 12 parsecs). Which metods of transportation that are being developed or thought about in the near/far future you think are the most promising?
Paul Carr (Space Systems engineer at NASA, podcaster, blogger, investigator)

I’m not optimistic about faster than light travel at any time in the future, although I would love to be proved wrong. Not only do we not have the technology to travel faster than the speed of light, we don’t know what technology we need, or even if it’s possible.

For the near future, something we could make happen would be nuclear space propulsion – first fission reactors, and then fusion reactors. My dream reactor would be a Helium 3 fusion reactor. Helium 3 is stable, and the Helium 3 fusion reaction produces Helium 4 (also stable), a proton (or two) (that can be used to generate electric power), and energy, but no neutrons. Neutrons are a problem that make most fusion reactors unusable for space applications. Such a reaction is far more mass efficient than chemical rockets, and with some work, could open up the entire solar system to us.

Fraser Cain (publisher at Universetoday.com, co-host of Astronomy Cast)

In the near term, I’m mostly excited about the potential for light sails, like the Breakthrough Starshot. If this technology can be developed, we could see spacecraft traveling out to Pluto within a few weeks or even days. Once we’ve mastered this tech, we can start sending spacecraft out to other stars.

Ciro Villa (technologist, application developer, STEM communicator)

Ever since human have been able to use their imagination they have been dreaming of traveling far away in space to explore and discover new worlds. Unfortunately, as much as our brains can dream it, we are limited by our physical and technological capabilities to only be able to travel very nearby.

So far in the history of space travel, chemical rockets have been the main mean of propulsion and other new propulsion technologies are only at their infancy. Many studies are underway and much literature has been created to envision the design of new ways to propel human made spaceships further in space and in shortest amount of times. In the shortest term, more efficient forms of propulsion are being developed such as electric variants like Ion, Plasma and Hall-effect thrusters some of which are already operational on some space crafts (https://en.wikipedia.org/wiki/List_of_spacecraft_with_electric_propulsion). Also, Solar sails which are still somewhat experimental in nature with their size challenges and limitations, are being investigated as another promising mean to accelerate spaceships beyond the confines of our Solar System.

More futuristic forms of propulsion are unfortunately still only on paper at this time and it will take willpower, new discoveries, money, time or most likely all the above to be further developed. The hope is that with the accelerating pace of technological advancements, some of these new, exotic propulsion technologies will materialize at some point in our future make human exploration of deep space a reality.

Andrew Rader (SpaceX engineer, MIT PhD, author)

For faster than light travel, it’s always possible that there will be some breakthrough that we can’t anticipate. Apart from that, I think we’re going to end up taking a long time to get to other stars, possibly in some kind of suspension or by just sending robots or human embryos. In terms of advanced propulsion in general, anti-matter offers the best mass to energy ratio we know of, but that’s a long way off (hundreds of years?). Fusion rockets might be possible before the end of the century. These would be great for travel in the solar system, but probably not to another star.

Robert Novella (co-founder and vice-president of New England Skeptical Society, co-host of Skeptics’ Guide to the Universe)

Chemical rockets have served humanity very well for many decades. They have launched satellites into orbit and blasted our probes and landers into the nooks and crannies of our solar system. They have lifted humans to low earth orbit and our moon. All of this has given us a priceless cornucopia of images and data and mind-boggling discoveries.

These types of rockets however are not nearly as adept at ferrying our fragile bodies much beyond the moon. To keep us healthy and happy requires vast ships that are prohibitively slow and expensive for trips to the closest practical planet, Mars.

Luckily, conventional rockets are only a tiny subset of all rocket types, yet I’ve been disappointed for literally decades that we have made so little progress on other types of rocket technology for transporting humans.

I’m still holding out hope for the widespread realization that rockets using nuclear fuel are the only real option we have in the near future for getting humans well past our moon. The energy density of nuclear is orders of magnitude that of chemical energy. Nuclear thermal rockets using fission for example could weigh half as much as similarly powerful chemical rockets. Directly comparing chemical vs nuclear rockets is complex but many have concluded that such nuclear rockets would be at least as twice as efficient as chemical rockets. This would allow trips to mars requiring half the time, or less, which is especially important considering the more time spent in space, the more time you’re exposed to life-threatening solar radiation and cosmic rays. Fission rockets would also allow for some serious maneuvering during a flight which is too expensive for modern chemical engines. You’re just not much of a spaceship in my book if you can’t maneuver easily.

A little beyond these fission rockets (which we can build now), we will create fusion rockets which should quickly predominate since they are even more efficient and produce less radioactive waste. Remember, a significant limitation to any ship’s maximum velocity is the amount of fuel required to reach that velocity. You could actually reach 10% of the speed of light with chemical engines but you’d need a gas tank the size of our sun to do that. Doable? Yes, theoretically. Practical? Ummm, no. Fission would require far less fuel to reach that speed and fusion even less. So what would require the least amount of fuel? Read on…

Long-term scenarios for Space Travel will certainly offer humanity many fascinating hi-tech options but some type of antimatter engines will probably be required if you want to move something space ship sized as close as possible to the speed of light. Sure, there may be some bizarre quirk of physics that allows for superluminal travel but…probably not, so don’t get your hopes up.

We know for certain right now that as you approach appreciable fractions of the speed of light, your mass starts increasing alarmingly fast (kinetic energy). To continue accelerating, your ballooning mass requires an exponentially increasing amount of energy. Eventually, to reach the speed of light itself you’ll need infinite energy to move your infinite mass. Unless you have infinite energy in your back pocket, you’ll never hit that speed.

To get as close as possible however, you’ll need an efficient method of energy conversion and that’s exactly what matter/antimatter annihilation provides. The energy released from such interactions is truly huge even if the masses involved are tiny (that is, after all, a key take-away from E=mc^2). The primary problem though is that we can’t practically convert all the byproducts of matter/antimatter collisions into the kinetic energy of our spaceship. The bottom line then is that we will probably not be able to ever get arbitrarily close to the speed of light. The estimates seem to be all over the place but somewhere between 40 and 70 percent of the speed of light could be attainable eventually.

I’m totally ok with a spaceship going 753 million km per hour.

Antonio Paris (Astronaut Candidate, Astronomy Professor, Planetary Scientist, Space Science Author)

For generations, science fiction has attempted to shape our future. From cameras on a watch as depicted in Dick Tracy; to warp speed, a common mode of travel used extensively in the Star Trek franchise. However, traveling faster than the speed of light or at warp speed, from a practical purpose, is not possible according to the laws of physics. The energy required to achieve the speed the speed of light, for example, would be infinite – sort of a an impossibility.

Today, and for the foreseeable future, spacecraft are limited to local orbits and interplanetary missions. There are numerous factors that shape spacecraft design and capabilities, but predominantly they are due to budget constraints, its intended function, and policy requirements. Extraordinary specific power and the ratio of jet-power to total spacecraft mass are required to reach interstellar targets within sub-century time frames. Some heat transfer is unavoidable and a tremendous heating load must be effectively handled. Thus, for interstellar rocket concepts of all technologies, a key engineering setback is controlling the heat transfer from the exhaust stream back into the spacecraft.

Based on research in the late 1950s to the early 1960s, it is technically possible to build spacecraft with nuclear pulse propulsion engines (i.e. driven by a series of nuclear explosions). This propulsion system contains the prospect of very high specific impulse and high specific power. This type of spacecraft, in my opinion, is our best hope for achieving interstellar travel.

In 1968, Project Orion team members proposed an interstellar spacecraft using nuclear pulse propulsion, which used pure deuterium fusion detonations with a very high fuel burn-up fraction. They calculated an exhaust velocity of 15,000 km/s and a 100,000-ton spacecraft able to achieve 20,000 km/s allowing a flight-time to Alpha Centauri of roughly 130 years. Later studies suggested that the top cruise velocity that can theoretically be achieved by a Teller-Ulam thermonuclear unit powered Orion spacecraft, supposing no fuel is saved for slowing back down, is about 8% to 10% of the speed of light. An atomic Orion can reach perhaps 3%-5% of the speed of light. A nuclear pulse drive spacecraft powered by Fusion-antimatter catalyzed nuclear pulse propulsion units would be comparably in the 10% range and pure matter-antimatter annihilation rockets would be theoretically capable of achieving a velocity between 50% to 80% of the speed of light.

In closing, although there have been numerous proposals and design concepts, spacecraft propulsion for interstellar flight is not an easy endeavor or economical. At current pace, we are at least hundreds or perhaps thousands of years before capable of interstellar travel to even the closest stars. Nevertheless, there are no doubts we will become an interstellar species in the foreseeable future.