This DARPA plan is the most moronic plan ever devised in the history of space exploration. The money is enough only for the paperwork and the design plans of some small part of the engine, and the actual one way trip technology that will be developed will be useless for any other trip. If the project is ever realized, the only outcome would be that there would be some skeletons in Mars inside some artificial habitat, without any true advances in technology that will help us colonize other planets.

The correct thing to do is to build a big mothership in space, like a small floating city, a ship that will travel easily to other planets using nuclear propulsion, with huge rotating sections to simulate gravity, and big enough space to host smaller spaceships that can land on planets and farming to satisfy the needs of its crew.

With such a ship, visiting other planets of the solar system, including Mars, will become routine. The trips will continue to be long, but they would be much more comfortable, due to the artficial gravity via rotation. People will eat naturally grown organic food, grown inside the spaceship, and so they will be feeded normally as on Earth.

The living space would be good enough for people to have their families on board, so as that they can relax and live a normal life, dedicating their work to science on board this spacecraft.

Now, that would be a true 100-year starship. Not this #ty death capsule DARPA and NASA have in mind.

Is that right? 35 million miles? there is no star within that distance, nearest star is 6 trillion miles away, (I think) or 4.2 light years, a 3 star system called Alfa Centuri, (spell checker on the fritz).

It's not going to stop once it gets going. Never going to happen but wars are winding down and have to spend some money