One of the themes in my upcoming book (that I wrote with my brothers, Bob and Jay) about future technology (coming Fall 2022) is the frequent disconnect between science fiction visions of the future and actual future technology. We can look at past science fiction about today and see how they did, but we can also look at current science fiction about the future to see how plausible their vision is. It’s a mixed bag, but one area where the disconnect is very strong is space travel. The problem is that space travel really sucks, and is going to suck for the foreseeable future. This is not only true for interstellar travel, but even travel within our own solar system. But science fiction authors want their action to take place in space and have their heroes travel to different worlds. So essentially they either need to just ignore major hurdles to space travel or make up sci-fi technology to solve those problems even if that means ignoring current science. Even hard science fiction has to allow 1-2 “gimmies” to make the storytelling work.

I think all of the challenges of space travel are potentially solvable. But I also think those solutions are going to be more complicated, involve more trade-offs, and take much longer than science fiction authors generally imagine. Toward that end, NASA is funding innovative research projects to chip away at the technological challenges of space travel. While these are early (phase I and phase II) research projects, they give a much more realistic glimpse into what space travel might look like over the next couple of centuries. Here are some highlights:

High-Expansion-Ratio Deployable Structures (HERDS)

The problem that HERDS technology is trying to address is the need for very large structures in space, while rocket launch systems have limited payload size. Therefore we have to limit the size of stuff we put into space, and/or we need multiple launches of different components that are assembled in space. Neither of these solutions are ideal. A HERDS system solves the problem by engineering an expandable structure that can be extremely compact in the cargo container of the rocket and then expand to its final structure once in the desired orbit. The authors of this proposal write:

“Specifically, we exploit two kinematic discoveries made in the last 5 years: shearing auxetics and branched scissor mechanisms. We intend to produce tube structures with an unprecedented 150x expansion ratio. Our Phase I NIAC study has demonstrated the viability of this approach and pointed us to several technical problems that must be addressed in Phase II. The key technical work in Phase II will be focused on four specific thrusts: 1) modeling and understanding the complex deployment dynamics of our expanding hierarchical structure in detail; 2) mitigating jamming during deployment in the presence of manufacturing errors and external disturbances using simulation and design optimization; 3) rapid prototyping and hardware-based design iteration to calibrate models and evaluate sub-system components; and 4) experimental validation of meter-scale prototypes with thousands of links to demonstrate deployment without jamming and high expansion ratios.”

There is a good reason why we might want a really big structure in orbit – artificial gravity. The lack of gravity in orbit is a major biological challenge to long term occupation of space. There are no current prospects for artificial gravity, because using rotation to generate such artificial gravity requires a giant structure. If you rotate a station or ship that is too small you create a lot of vertigo and disorientation. We need “kilometer scale” structures to generate 1 g with 1-2 RPMs.

One side point that comes out in this proposal is the need for advances in material science. I have often said that material science is underappreciated, and can have the largest impacts on technology of any innovation. Advanced materials changes the game. But we cannot count on specific advances, so these projects need to do the best they can with existing materials.

Digital Spacesuits

We have not yet achieved the science-fiction vision of a comfortable slim spacesuit that allows for extreme mobility. Pressurize space suits are still a challenging technology. In the Apollo era spacesuits were custom made to fit each individual astronaut. These worked well, but were expensive and not practical for an expanded astronaut core going into the Space Shuttle era. For that reason NASA shifted to a modular design with basic sizes, so that one suit could be worn by many astronauts. These suits, however, were often uncomfortable, caused injuries due to pressure points, limited strength and mobility, and at times limited which astronauts could use them. NASA is still developing their Artemis spacesuit, which follows the Space Shuttle approach but with more sizes and better designs to fit a wider range of astronauts. This is taking longer and proving more difficult than they initially projected.

One solution is to return to the Apollo era approach of tailored individual space suits for individual astronauts. In order to accomplish this in a cost effective way, this research project proposes the development of a digital thread technology in which astronauts are scanned and then suit components are 3D printed custom to their body. This is a phase I feasibility study:

The study will identify all key components of a spacesuit and current manufacturing technologies; map those to DT components; identify technology gaps; benchmark required technologies and capabilities in industry, academia and government; and develop a conceptional DT model for future Spacesuit Development and operational support.  The digital thread could also include components to model suits in any given planetary environment and to model logistical requirements (supply and consumables).

In addition to individualized space suits, this will allow for the printing on sight, on the Moon or Mars, of replacement parts. This will be critical for long term missions. Moon dust destroyed the Apollo space suits after just days on the lunar surface. Not only will the new suits need to be much more resilient to lunar dust, they will need replacement parts.

Repelling Cosmic Rays

Cosmic rays are the dirty little secret of humans in space. These rays are a constant drizzle of high energy particles, and we currently have no technology to protect astronauts from them. When I asked a NASA scientist what their solution was she said, “Get there fast.” That’s it – limit astronaut exposure. Estimates are that humans can withstand about 6-9 months of exposure to cosmic rays before the long term risk of cancer becomes too high. They are also exploring ways to make humans more resilient to the damage from cosmic rays. But shielding is off the table. The problem is, conventional shielding would be too heavy. Also, moderate shielding makes cosmic rays worse, because some of the rays penetrate the shielding and then bounce around on the inside.

The proposed research project is for “CREW HaT: Cosmic Radiation Extended Warding using the Halbach Torus.” Essentially this is a design for a magnetic field to surround the crew compartment and divert cosmic rays away from the crew, while limiting the magnetic field inside the crew compartment. The project will test the combination of a new design and recently developed superconducting tape. The researchers project it can divert 50% of cosmic rays. This is not a total solution, but would double the time astronauts could spend in space – enough to get to Mars and back.

Take a look at the other funded projects, and it also gives you a good idea of the challenges we are currently facing in space travel.