It sounds like you’ve managed to unify Relativity with Quantum Mechanics, then? (to “fulfill relativistic quantum physics” in “picoyoctometric detail” no less?)

In that case, congratulations, Mr. Future Nobel Laureate!

I actually don’t like the idea the way they present it on the show, because they show it being done by a private company, I certainly hope the United States Armed Forces would not trust a private company to take proper care of thousands of nuclear weapons. If they were using the Orion Drive, the ship should have been USS Phaeton (military designation meaning “United States Ship”, a commissioned Navy warship) not just Phaeton.

The Mini Mag Orion concept would be better, where you have fissile material, eject it out the back of the craft, and use a magnetic field to confine it (achieving critical mass) until fission occurs. That way there is no nuclear weapon aboard the ship.

Personally my favorite is VASIMR, it is a plasma drive that can use hydrogen. Then you can use your friendly neighborhood gas giant planet to refuel, and again, no nuclear weapons involved.

Also I thought it was a little weird on the show that they were acting like the VR would be their only source of entertainment underway. What about movies, books, music, etc.? We get by that way on submarines with no problem.

–Brian (former us navy submariner)

I was thinking about some like that but it’s better to read it from somebody else.

Thanx.

The speed isn’t permanent at all. The simple rule is that you accelerate continuously until, approximately halfway to the destination, you turn the ship around and continuously decelerate.

If you do not do this you’ll overshoot your target (and that’s assuming you miss the destination. If your aim is true you slam into the destination!). Overshooting is not like missing a turnoff on a highway; at these speeds you’ll have NO CHANCE WHATSOEVER of slowing down in a reasonable timeframe.

However the “accelerate halfway, decelerate halfway” rule will probably need some modification in reality. If the propulsion system is a reaction mass system you may need to conserve mass. In that case you accelerate until you’ve used half your reaction mass.

If the propulsion system has a top end speed and you reach that early, you might as well shut it down. I’m talking about Newtonian mechanics here.

If you start hitting relativistic speeds (yeah, yeah, they’re all relative…), then your ship gains apparent mass until it hits infinity at the speed of light. Therefore somewhere above .9c, even if your drive has more apparent power, your ship resists accelerating more and more. Eventually it’s not worth trying any further.

Finally, your drive system may have power limitations, or you may wish to devote it’s power to non-propulsion activities. Power conservation or allocation may cause you to take your foot off the accelerator.

The effect of all these flight plan modifications is that you spend an interval in the middle of the trip coasting. You still accelerate for a set period at the start of the voyage and decelerate for an identical period of time at the end. This ignores so-called black swan events, like inventing a better propulsion drive during the trip itself, or being boarded by aliens (!).

Anybody?

So, how much time will have passed on Earth, being that in this example, it’s “relatively” stationary?

Accelerating at 1 gee to 0.9c takes 1.43 years ship-time and you travel 1.254 light-years (non-Lorentz contracted light-years that is), so that’d need to be factored in.

As for nukes vaporising the pusher plate – nope. They set off BIG nukes next to metal spheres coated lightly with graphite – the spheres survived, tho a thin layer of graphite was ablated. That’s what gave the ‘Orion’ designers confidence it would work back in the late 1950s and all the subsequent tests pretty much confirmed it.

A few problems arise. To get decent efficiency the pulse-units need to produce high quality directed plasma. With fission bombs a range of ‘filler’ materials gave the blast the desired directionality. But m-am reactions produce LOTS of gamma-rays and converting their energy into directed plasma isn’t straightforward. I guess the F in the SF is some ‘unobtainium’ to reflect the gamma-rays.

Protection against the interstellar medium is a must. Would’ve been nice to see some details on what the writers assumed for that – more ‘unobtainium’? Or magnetic deflection and a forward-facing ‘ioniser beam’ to charge up the impinging ISM? The ‘unobtainium’ can then reflect away the resulting x-ray bremstrahlung.

Finally, travelling at 0.9 c means that you’ll only receive signals from Earth from part of the journey time. Travelling 10.5 light-years at 0.9 c means you take only 1.167 years longer to get there than light does – thus you’ll only get 1.167 years worth of transmissions during the journey and have to wait for the rest to arrive. You only ‘catch up’ to the apparent future on Earth by flying back home.

These exact figures assume instant acceleration but the result is similar even when we factor acceleration in. In the case of a 1 gee acceleration over the whole trip then something curious happens. Imagine the Earth is sending us a clock-signal. On arrival at Epsilon Eridani how much time has elapsed as measured by the clock-signal from Earth? Just 1.79 years. Yet our ship-board clocks will say 4.94 years…

Ponder that.

So as the ship accelerates the mass is not increased due to the decreasing mass of the ballast?

I think the concept of utilizing “a giant shock absorber” to be silly.

Instead control the amount of force applied, this is the same thing as the effect of the shock absorber except less moving parts and mass.

Also, early interstellar craft will likely use multiple forms of thrust, where efficiency and mass of the thrust are more important.

Such as using both a solar sail and an ion drive?

But I suppose the really notable thought is that these endeavors must have a purposeful reason. Generally given our nature, I would say that we’d need to use most of the resources of our solar system before we’d truly have much need/want for interstellar travel.

That is unless we find ways to break special relativity.

I could not disagree more. Human beings crave communication and will do almost anything to get it.

Ever heard of snail mail? Letters routinely take 4 days or longer by ground delivery, and yet were the standard for long distance communication for over 100 years.

I’ve worked in remote locations and news from “home” is a big deal. People want letters, newspapers, magazines, books, whatever they can get. Work in a camp often comes to a complete stop when the mail comes in. It’s an important morale booster; easily as important for morale as good food.

Maybe a spoken conversation will not be viable at a distance, sure. That breaks down pretty quickly, even at Mars type distances. Interactive communication is possible but becomes cumbersome. However unless the spacecraft is so big that people are taking their entire social circle and all interests with them, spacefaring people will want news from Earth. Even if it takes several years to get there.

Don’t forget that electromagnetic communications can (and would) be sent as gathered. The recipients can receive a nearly continuous stream of communications in a “pipeline” sequence. There don’t have to be any gaps.

At a distance of several Light Years from Earth, all communications received would be that many years old. Despite this there would be an uninterrupted stream of data, flowing in both directions. This would maintain a connection between the Earth and the voyagers, and interest in each other. The turnaround becomes a huge issue but otherwise the communication link can be fully functional.

No, the only thing that would likely kill a communications link would be if Earth stopped caring about it’s long distance astronauts, or vice versa. As long as the interest is there they will find a way.