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#1 2004-08-02 11:17:09

Neuromancien
Banned
From: Paris
Registered: 2004-07-29
Posts: 1

Re: Scenario

Hello !

How would a manned mars mission look like using a VASMIR propulsion or another form of electrical propulsion ? What kind of launch vehicle would be used ? Do we need to send the earth return vehicle or equipment before, like in a Mars Direct mission ? How long would take the travel and the whole mission ? What about trajectory, launch opportunities and launch mass ? Would the mission be more flexible than a Mars Direct scenario ? And how would such a mars mission look like using a very fast spaceship (for example an americium-based space vehicle which is theoritically able to travel to mars in 2 weeks). I read somewhere that some ion-engine could shorten the trip to 1 month ?

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#2 2023-02-02 08:23:20

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,133

Re: Scenario

This appears to be a topic that received no replies in 2004.

It is nearly 20 years later.

From my perspective, not much has changed.  The ONLY practical spacecraft propulsion method we humans can muster is good old reliable chemical propulsion of many tons of mass in accordance with Newton's Laws.

However, if past is prologue, we (humans) are about to see invention, development and implementation of systems that permit movement throughout the Solar System at rates greater than are possible with chemicals.

(th)

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#3 2023-02-02 08:36:29

Void
Member
Registered: 2011-12-29
Posts: 7,093

Re: Scenario

Off topic just for a moment, I now can log on with just one try.  Previous it might be 30 tries.  Did you guys change anything? in the last day or two?

On the topic, and it's previous two posts.  Quote:

From my perspective, not much has changed.  The ONLY practical spacecraft propulsion method we humans can muster is good old reliable chemical propulsion of many tons of mass in accordance with Newton's Laws.

I am afraid I cannot hold that as valid.  The "Dawn" mission was electric propulsion, although of course to get into space chemical rocket method was used.  https://en.wikipedia.org/wiki/Dawn_(spacecraft)

In reality we have not sent humans either to Mars or Ceres by any method, not yet. 

I recently read an article about "Amping Up" hall thrusters.  I think that this is it: https://www.futurity.org/hall-thrusters-2864142-2/  Quote:

SOUPED UP HALL THRUSTERS MIGHT GET PEOPLE TO MARS
JANUARY 26TH, 2023
POSTED BY KATE MCALPINE-MICHIGAN
"We named our thruster the H9 MUSCLE because essentially, we took the H9 thruster and made a muscle car out of it by turning it up to 11—really up to a hundred, if we're going by accurate scaling," says Leanne Su. (Credit: NASA's Marshall Space Flight Center/Flickr)

And now, I will try to explain the chances that a ship launched from the orbit of Phobos might loop around Earth, and then go back to Mars, to be sucked into its gravitational field, by Ballistic Capture.  For the moment, lets suppose the propellant is Argon gotten from Mars.  The energy source is not likely to be nuclear, as people would not enjoy an nuclear reactor doing a gravity assist with Earth.  So, probably solar.

There is no law that says that the ship launching from Mars orbit could not use a tug for assistance to get out of the Martian gravity well.
That could be chemical or nuclear.  If nuclear, it might take a different path back to Mars, or might not leave the Martian gravity well at all, itself.

If Ballistic Capture annoys you, then lets just use the boost from a gravity assist from Earth, and the Hall Thruster system to "Spiral" up to Martian orbit.  But Ballistic Capture is especially good with electric propulsion.

But, Ballistic Capture anyway: https://www.scientificamerican.com/arti … e%20planet.  Quote:

Getting spacecraft to Mars is quite a hassle. Transportation costs can soar into the hundreds of millions of dollars, even when blasting off during "launch windows"—the optimal orbital alignments of Earth and Mars that roll around only every 26 months. A huge contributor to that bottom line? The hair-raising arrivals at the Red Planet. Spacecraft screaming along at many thousands of kilometers per hour have to hit the brakes hard, firing retrorockets to swing into orbit. The burn can require hundreds of pounds of extra fuel, lugged expensively off Earth, and comes with some risk of failure that could send the craft careening past or even right into Mars.

This brute force approach to attaining orbit, called a Hohmann transfer, has served historically deep-pocketed space agencies well enough. But in an era of shrinking science budgets the Hohmann transfer's price tag and inherent riskiness look limiting.

Now new research lays out a smoother, safer way to achieve Martian orbit without being restricted by launch windows or busting the bank. Called ballistic capture, it could help open the Martian frontier for more robotic missions, future manned expeditions and even colonization efforts. "It's an eye-opener," says James Green, director of NASA's Planetary Science Division. "It could be a pretty big step for us and really save us resources and capability, which is always what we're looking for."


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The premise of a ballistic capture: Instead of shooting for the location Mars will be in its orbit where the spacecraft will meet it, as is conventionally done with Hohmann transfers, a spacecraft is casually lobbed into a Mars-like orbit so that it flies ahead of the planet. Although launch and cruise costs remain the same, the big burn to slow down and hit the Martian bull's-eye—as in the Hohmann scenario—is done away with. For ballistic capture, the spacecraft cruises a bit slower than Mars itself as the planet runs its orbital lap around the sun. Mars eventually creeps up on the spacecraft, gravitationally snagging it into a planetary orbit. "That's the magic of ballistic capture—it's like flying in formation," says Edward Belbruno, a visiting associated researcher at Princeton University and co-author, with Francesco Topputo of the Polytechnic University of Milan, of a paper detailing the new path to Mars and the physics behind it. The paper, posted on arXiv, has been submitted to the journal Celestial Mechanics and Dynamical Astronomy.

Ballistic Capture is said to be more flexible as per launch window, but cruse time is longer.  But if we have a large ship with full life support to maintain human health, we might wish to consider the method.

But, a reminder, with electric propulsion you don't have to do either a Hohmann maneuver, or ballistic capture.  The dawn mission is evidence that it was possible to creep up on both Vesta and Ceres without those, I believe.

I think we should evolve our thinking to the notion that Mars orbits are associated with resources for propulsion.  The sun is a means for energy for propulsion, which gets better the closer to Earth's orbit the craft is.

For the moment can we call this a "Loop Method?".  The method fills resources at the orbit of Mars, may be assisted on launch by a tug, swings down to do a pass of the Earth, and may modify its orbit by that gravitational pass, and then uses electric propulsion to complete the loop back to Mars.  So, we may be using gravitational propulsion as well in the pass of Earth.

Other forms of propulsion that might be added are.
1) Sailing with Photons, (And that may include a laser assist).
2) Sailing on the solar wind.  (That may involve spinning magnetic fields).
3) Oberth Effect.  (That requires a strong propulsion such as Chemical or Nuclear).
4) Mass Driver.  That might involve icy pellets with magnetic materials included, in order to shoot them out with a linear mass driver.

The four are under development or are considered by some to be possible.

But we definitely have Chemical, Electric Ion, and gravity assist methods of propulsion, they are real and have been done.

Things are evolving.

Done.

Last edited by Void (2023-02-02 10:18:38)


Done.

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