All Aboard the Bombardier Space Train

[bobbymike]

http://www.sciencealert.com/meet-solar-express-the-space-train-concept-that-can-get-to-mars-in-two-days

 

[Apophenia]

It's worth noting that Charles Bombardier's day job is on the Ski-Doo side of the family - Bombardier Recreational Products - which no longer has anything to do with Bombardier Aerospace. My favorite Charles Bombardier design is his Nunavik Arctic Express ekranoplan concept

http://aviationweek.com/blog/designer-airliners-ice-road-flying

 

[starviking]

Sooo much wrong with that idea. I'll illustrate one:

If ever a reality, Bombardier and his team envision Solar Express travelling at roughly 1 percent the speed of light - about 3,000 kilometres per second (1,864 miles per second) - dropping the travel time between Earth and Mars to less than two days.

That's enormous compared to the Solar System escape velocity at Earth's orbit - around 4 km/s. Negelcting how it gets to such a velocity, It's not going to be doing any cycling*- just shooting off into deep space.

*And it has an odd concept of cycling, using slingshot manouvres to pick up speed - never stopping - but orbiting planets to pick up cargo and passengers! I don't even think the slingshots can do what they claim - in effect a slingshot is limited by the orbital speed of the celestial body being used - and 1% of the speed of light is waaay out.

 

[Orionblamblam]

Oy. A cycler? Good, fine, wonderful. One percent lightspeed? You just clued me in that you don't know what the hell you're talking about.

Not only is 0.01c beyond any imaginable practical propulsion technology, it's a speed that makes hash of the idea of cycling. Unless you applied a whole lot of braking, you'd just blow past the target planet like it wasn't even there.

Worse: let's say you've got your magical impulse engines that can boost you to 1% c and down again for an Earth-Mars run. What level of acceleration is going to be provided to attain that in the time and distance you have, and will there be anything left of the passengers but a red paste coating the walls when you're done?

 

[sferrin]

Details, shmetails.

 

[Michel Van]

this homepage give more detail
http://imaginactive.org/2016/08/solar-express/

Huge solar arrays located along the train’s path could be used to capture solar energy and transfer it by laser to super capacitors...
... but the main propulsion system should take the form of an ion thrusters....

sounds like SPS size monsters in interplanetary orbit, a fleet of them...

Mobile Cargo Bays (MCBs) and other spacecraft would allow for transhipment between celestial bodies (planets, moons, asteroids) and the trains. These vessels could use different types of propulsion to rendezvous with the Solar Express. They would need to match the speed of the train to attach and carry on their transhipment.

yeah, with delta V on 2% of c to catch up with Space Train and decelerate back at target.
ohh by the way, with this kind of Engine power for MCBs, you don't need the Space Train
just aim for target, start the engine and drive in straight line to it !
and a MCB can make a Proxima b fly by in around 215 years...

 

[Kryptid]

Worse: let's say you've got your magical impulse engines that can boost you to 1% c and down again for an Earth-Mars run. What level of acceleration is going to be provided to attain that in the time and distance you have, and will there be anything left of the passengers but a red paste coating the walls when you're done?

Assuming I put the right numbers into the online calculator I found, it's between 16 and 17 G (assuming closest approach between Earth and Mars). That acceleration could be reduced to about 2.3 G if the maximum distance between Earth and Mars is used instead (ignoring the very big problem of the Sun being in the way for any spaceship trying to travel along this route). Routes between these two extremes might actually be survivable.

 

[Kevin Renner]

Never mind this makes a nuc look like a wet firecracker