You can say that again. LOL!.
Seriously, I agree.

It will happen eventually. But we won't escape human foibles. I am guessing at least some forms of human ignorance will follow humankind off earth and history will continue to rhyme.

It will happen eventually. But we won't escape human foibles. I am guessing at least some forms of human ignorance will follow humankind off earth and history will continue to rhyme.

"but then what?"
They did this in Arthur C Clarke's 2061. They spent half the trip slowing down.
Suppose the trip to Mars is 100 million km = 10^11 m. You start slowing down 5 * 10^10 meters into the trip.
We know x = 1/2 a*t^2. t = 1.5 days * 60 * 60 * 25 = 129600 sec. We solve for a and get a= 6 m/s^2. At peak v, we're at 0.13% of c.

Ramming speed!

Just got back from being offline for nine hours. Don't think that's why my Charter went south, though. Ha! Ha!
Just changed my mind about switching my DirectTV back to Charter, though.
Someone I know with total Charter, who had her gall bladder removed yesterday, could not watch TV until about 8:45 PM today.

I forget who said that science fiction is mainstream fiction and what we call mainstream fiction is historical fiction set in the present.

Not Mars, Venus or Luna would be the better choice for them. Mars will require actual work for an extended term. ;)

You aren't that far off. This technology and concept have been worked on for quite some time - nothing new here. The reality is that for light sails to work well enough they are best started closer to the sun. So in a sense you do have to first go "into the wind".

Mars in three days. Wow! The Liberals want a place to escape from Trump. They are threatening to go to Canada and New Zealand. I've heard from a New Zealand Gulcher that they don't want them, so Mars would be a wonderful place for them. They could leave tomorrow and be there in time to miss the Trump's swearing in.

Being a sailor...I would turn into the wind, (cosmic wind that is) and take in the sails as they flap...laughing

Yes. Gravitation exchange maneuvers are actually the result of an exchange of momentum between the spacecraft and the celestial body by means of gravitational coupling. Capture of a spacecraft, at Jupiter for example, requires a combination of gravitational exchange and propulsion. With current technology neither is sufficient to do the job alone.
Again, current technology will not support an interstellar mission with anything other than a high velocity fly by.

NASA stuff - http://www.starznbarz.com/Space-shuttle

Currently antimatter occurs as part of the decay chain of certain radio isotopes and it can be manufactured in high energy particle accelerators. The company I am working with manufactures a radioisotope that produces positrons, the anti particle of the electron, as part of its decay process. It is similar to the process that produces the radionuclides used in medical PET (Positron Emission Tomography). With current technology the cost of antimatter production is very high, over 100 million dollars per gram! However, one gram of antimatter produces sufficient energy to propel a 100 ton space craft to Mars and back several times. Part of my consulting job is to seek lower cost ways to manufacture antimatter and store it safely.

I know there are times in my life I've wished for that shield.

And others where I've wished for that energy gun...

While all that is true, gravity's actions are insufficient for it to act as a brake on most bodies travelling at the speeds of a spacecraft precisely because of the vectors involved. The actual entry angle toward any planet is very small, as too steep an angle and the vehicle actually picks up speed as it plummets toward the planet's surface while too oblique and the vehicle skips right past. At the speeds of an intrastellar object (comets and asteroids) we find very few incidences where the circumstances are sufficient for unassisted capture, which is what you allude to. And these speeds in general are much slower than the velocities which would be necessary to reach the limits of the solar system within a person's lifetime let alone a star even as close as Alpha Centauri.

Using a light sail has been the design stage for some time. Back in the 1950's the young gun scientists and engineers at General Atomics came up with the Orion concept of using nuclear explosives dropped behind a vehicle using a pusher plate with pistons to get to Mars in the same amount of time. Nasa claims it was theirs but General Atomics was competing with them at that time.As far as I'm concerned Nasa steals concepts and make them their own.

Don't forget Atlas Shrugged is categorized
As science fiction.:)

Hi ProfChuck,
I am curious to know , is there a technique to harvest or obtain antimatter?

Brakes??? We don't need no stinking brakes!

The technology is there, its just a little bit of science fiction yet to product the anti-matter in any level of quantity yet I would think (and sufficiently contain it in a magnetic bottle that would survive a rocket-launch).

Fusion is good but antimatter is even better by a factor of several thousand. One of the companies I am consulting for has demonstrated a functioning antimatter power generator and rocket engine. Far from being science fiction this is a real system that is scheduled for space qualification within 5 years.

That would drive a nuclear power-plant, for reliability, you would want a large orbital station-based approach to leverage solar and avoid the many-month planet-wide dust storms that frequent the Mars atmosphere. Realistically, we need fusion.

"Gravitational attraction does not provide braking". Not quite true. A gravitational encounter is actually best understood by viewing the problem in terms of vector calculus. An incoming vehicle has a velocity and direction that is best described in terms of a vector and its first and second derivatives. The same may be said of the planetary body that it is approaching. Acceleration simply means changing velocity which can be either increased or decreased in the reference frame of the planetary body. It's all a function of the entry angle.

Hohmann transfer orbits modified to accommodate constant thrust systems have been examined and several acceleration and breaking strategies have been identified. The celestial mechanics is a bit tricky but there is nothing that is beyond our current understanding or computational capability.