Posted on 12/21/2020 9:34:04 PM PST by BenLurkin
The biggest challenge (or constraint) is the mass of the payload (spacecraft, people, fuel, supplies etc) needed to make the journey.
The payload mass is usually just a small percentage of the total mass of the launch vehicle.
For example, the Saturn V rocket that launched Apollo 11 to the Moon weighed 3,000 tons.
But it could launch only 140 tons (5% of its initial launch mass) to low Earth orbit, and 50 tons (less than 2% of its initial launch mass) to the Moon.
Mass constrains the size of a Mars spacecraft and what it can do in space. Every maneuver costs fuel to fire rocket motors, and this fuel must currently be carried into space on the spacecraft.
SpaceX's plan is for its crewed Starship vehicle to be refueled in space by a separately launched fuel tanker. That means much more fuel can be carried into orbit than could be carried on a single launch.
This saves a lot of fuel, but can result in missions that take years to reach their destinations. Clearly this is something humans would not want to do.
Both Earth and Mars have (almost) circular orbits and a maneuver known as the Hohmann transfer is the most fuel-efficient way to travel between two planets. Basically, without going into too much detail, this is where a spacecraft does a single burn into an elliptical transfer orbit from one planet to the other.
A Hohmann transfer between Earth and Mars takes around 259 days (between eight and nine months) and is only possible approximately every two years due to the different orbits around the Sun of Earth and Mars.
A spacecraft could reach Mars in a shorter time (SpaceX is claiming six months) but—you guessed it—it would cost more fuel to do it that way.
(Excerpt) Read more at phys.org ...
In other words, don’t pack your suitcases just yet.
Send cargo craft ahead and park in orbit, even land so they know everything they need is there and intact on the surface before they leave Earth. Maybe try out some solar-sail tech or solar-wind tech for the cargo craft. Also send some to the satellites as well. Make it a serious operation and not some shoestring deal. You’re a long ways from a gas station or a Walmart when you get to Mars.
There is no reason to go to Mars other than to see what is there. No soil, -89 degree temperature, and no water. This is a fools errand—but hey Elon Musketeer, would love to see you throw away all your money and come back to earth.
I suppose once you iron out wormhole travel and warp drive, it’ll be a hop, skip, and a jump.
If the various space agencies and private companies don’t sort out how to either shield humans from the massive amounts of radiation they’d be absorbing on this trip, or changing human biology to stay healthy in a high radiation environment, it’s all moot.
I’ll never understand why the same people who fervently believe science can turn Mars into a habitable oasis for colonization, something which has never been accomplished and we have no experience achieving, but it’s impossible for humanity to handle climate change and improve our environment on earth, which even primitive cultures have managed to do for thousands of years and we’re getting better at every day.
The Transporter, Jim!
Mars ain’t no kind of place to raise your kids.
Wasn’t there a plan to send a fuel production plant to Mars before manned travel there?
We may need to terraform Mars so we have a place to escape the coming internal and external communist takeover.
Elton John wrote about going there....old news.
What if we don’t want them safely back again?
(And, with that, I bid all good, decent people here good night.)
I don’t think that he plans to return.
I’d live in a tiny building or ship and float around all day if it got me away from our government. I’d take the one way trip and maybe we could start a fresh society without communists.
Yup first thing I thought of was getting away from the communists. Give us some lazer blasters and let’s go !!
And how will our soon-to-be revolutionary socialist nation pay for that?
What am I forgetting? Sometimes I wish I had Total Recall
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.