A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » Space Science Misc
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Travelling to Mars



 
 
Thread Tools Display Modes
  #1  
Old December 11th 03, 02:09 AM
Mervo
external usenet poster
 
Posts: n/a
Default Travelling to Mars

Hardly a week goes by without some news item about Mars and the
likelihood of manned flight to it.

I ask, where is there a cape Canaveral launch facility on the red planet
it in order to facilitate a return journey to Earth. Because that's what would be needed
given a not dissimilar gravity of the two planets.

We are all aware what is need to launch a human into space from earth.
It simply cannot be done with the crafts that took off from the moon. Similarly
such a craft would not be powerful enough to escape the gravity of Mars.

Those people who enthuse about manned spaceflight to mars (curiously
enough) never seem to mention this basic problem.


Mervo

  #2  
Old December 11th 03, 05:51 AM
Jon Berndt
external usenet poster
 
Posts: n/a
Default Travelling to Mars

"Mervo" wrote in message

I ask, where is there a cape Canaveral launch facility on the red planet
it in order to facilitate a return journey to Earth. Because that's what

would be needed
given a not dissimilar gravity of the two planets.


The acceleration due to gravity on the moon is 1/6 that on earth; on Mars it
is roughly 1/3 that on earth. Both of those are dissimilar.

We are all aware what is need to launch a human into space from earth.
It simply cannot be done with the crafts that took off from the moon.

Similarly
such a craft would not be powerful enough to escape the gravity of Mars.


Nobody is proposing that a lunar module be used on Mars. It would obviously
require the design and construction of a new spacecraft.

Those people who enthuse about manned spaceflight to mars (curiously
enough) never seem to mention this basic problem.


What on earth are you talking about?

Engineering vehicles to accomplish a Mars mission would not be so much a
problem as finding the money to fund it.

Jon

  #3  
Old December 11th 03, 02:38 PM
Earl Colby Pottinger
external usenet poster
 
Posts: n/a
Default Travelling to Mars

"Mervo" :

Hardly a week goes by without some news item about Mars and the
likelihood of manned flight to it.

I ask, where is there a cape Canaveral launch facility on the red planet
it in order to facilitate a return journey to Earth. Because that's what
would be needed
given a not dissimilar gravity of the two planets.

We are all aware what is need to launch a human into space from earth.
It simply cannot be done with the crafts that took off from the moon.
Similarly
such a craft would not be powerful enough to escape the gravity of Mars.

Those people who enthuse about manned spaceflight to mars (curiously
enough) never seem to mention this basic problem.


Sorry, but it appears that you did not do much thinking or research before
posting here. May I suggest that you spend a little time reading some books
in your local library showing some of the past designs planned for a Mars
trip. You will find all your problems where addressed decades ago and that
is why we don't bother discussing them now.

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

  #4  
Old December 23rd 03, 10:04 AM
Nick Maclaren
external usenet poster
 
Posts: n/a
Default Travelling to Mars

In article ,
"Jon Berndt" writes:
| "Mervo" wrote in message
|
| I ask, where is there a cape Canaveral launch facility on the red planet
| it in order to facilitate a return journey to Earth. Because that's what
| would be needed
| given a not dissimilar gravity of the two planets.
|
| The acceleration due to gravity on the moon is 1/6 that on earth; on Mars it
| is roughly 1/3 that on earth. Both of those are dissimilar.

And it's the potential that matters, anyway, which makes it even
easier.

| Those people who enthuse about manned spaceflight to mars (curiously
| enough) never seem to mention this basic problem.
|
| What on earth are you talking about?
|
| Engineering vehicles to accomplish a Mars mission would not be so much a
| problem as finding the money to fund it.

Well, yes, but the aspect that I notice often gets skimped is
the human one. The physiological and psychological problems
of such a trip are non-trivial. And one difference between
extended sessions in orbit is that they can be cut short
in emergency, and a Mars trip couldn't be. The psychological
effects of that can't be discounted, either.

I don't know what the chances of a serious problem developing
would be, but they must be large enough to be a major concern.
Back in the days of the comparably stressful sea voyages, there
wasn't the same regard for human life and welfare. If a crew
member got seriously ill, he died. If one developed a phobia
and threatened the ship, he ended up in irons or overboard.
And nobody made a fuss about it.

I know that people are studying that, but the results are not
widely known - at least not to the lay public. What sort of
probability of failure would be expected, due to this sort of
reason? I don't have a clue, but it won't be zero.


Regards,
Nick Maclaren.

  #5  
Old December 28th 03, 09:39 PM
Christopher M. Jones
external usenet poster
 
Posts: n/a
Default Travelling to Mars

"Jon Berndt" wrote in message ...
"Mervo" wrote in message

I ask, where is there a cape Canaveral launch facility on the red planet
it in order to facilitate a return journey to Earth. Because that's what

would be needed
given a not dissimilar gravity of the two planets.


The acceleration due to gravity on the moon is 1/6 that on earth; on Mars it
is roughly 1/3 that on earth. Both of those are dissimilar.


What really matters is the Delta V involved. As it happens,
the delta V from Mars to escape velocity is much less than
even from Earth to low Earth orbit (~5.2 km/s vs. ~8.5km/s).
So much so, in fact, that Single Stage to Escape Velocity
rocketry from Mars is *easy*. Several first stages for
launch vehicles currently in production could be changed to
launch vehicles with *significant* paylod to escape velocity
from the Martian surface with ease. The point is that the
technology for getting off Mars with a rocket is well in
hand, the engines, fuels, and structures we have today are
much more than up to the job, the trick is getting the
vehicles and all the fuel where you need it.


We are all aware what is need to launch a human into space from earth.
It simply cannot be done with the crafts that took off from the moon.

Similarly
such a craft would not be powerful enough to escape the gravity of Mars.


Nobody is proposing that a lunar module be used on Mars. It would obviously
require the design and construction of a new spacecraft.

Those people who enthuse about manned spaceflight to mars (curiously
enough) never seem to mention this basic problem.


What on earth are you talking about?


I think I've figured out what he's getting at. He's trying to
imply that the Moon is a much different place than Earth and
Mars, and that in rocketry Mars is more like the Earth than
the Moon. Specifically, he thinks, I believe, that a full
launch pad and gantry would be needed for launching from Mars,
instead of the simple setup for leaving the Moon. He is, as
it turns out, quite completely wrong. Mars is not the Moon,
but it is not Earth either. More importantly, even on Earth
a full launch gantry and pad are not necessary for launch,
there are other ways to do it. For Earth gettng to orbit is
such a close thing with the technology we have that it's
better to not hamper the performance of the launch vehicle by
putting the mass burden on it instead of on a gantry and pad.
But for Mars there's quite enough margin available so that
designing a rocket that doesn't need a gantry and pad won't
result in a huge mass penalty and will still have substantial
payload to orbit or to escape velocity.

Note that the Delta V needed to launch from Mars to escape
velocity is less than that achieved by top of the line
ballistic missiles, some of which are fired from submarines
or mobile trucks. The mass of the "launch facilities" for
those missiles is very much less than for a conventional
gantry, and even if launching from Mars required a similar
mass penalty, it would not pose a great engineering
challenge.

As for people considering manned spaceflight to Mars, they
*have*, in fact, thought of all of this, and worked it into
their plans. Sometimes with enormous detail. That the
solutions to the problem required much less massive
structures than a full launch gantry and pad probably caused
him to overlook their very existence.


Engineering vehicles to accomplish a Mars mission would not be so much a
problem as finding the money to fund it.


Yup.

  #6  
Old January 1st 04, 03:14 AM
Martha H Adams
external usenet poster
 
Posts: n/a
Default Travelling to Mars

Attitude toward loss of lives is not the only difference between the
sailing exploration voyages and a Mars trip. I think a good
background book would be,

Patrick O'Brian, The Golden Ocean (1956)

based upon a voyage made before a remedy was found for scurvy. Note
much use made of locally available materials for shipbuilding and
resupplying. Copying knowhow abstractions from the sailing days into
a Mars trip is a good idea, but it's going to be hard to do.

Re The Golden Ocean. Clear a couple of hours before you start it.
Once you're in it you won't be stopping til the end.

Cheers -- Martha Adams

  #7  
Old January 2nd 04, 07:11 AM
Hop David
external usenet poster
 
Posts: n/a
Default Travelling to Mars

Christopher M. Jones wrote:

What really matters is the Delta V involved. As it happens,
the delta V from Mars to escape velocity is much less than
even from Earth to low Earth orbit (~5.2 km/s vs. ~8.5km/s).


Plus the Martian atmosphere is much thinner. I'd think this would also
make the Martian launch easier.

--
Hop David
http://clowder.net/hop/index.html

  #8  
Old January 5th 04, 05:10 AM
BD
external usenet poster
 
Posts: n/a
Default Travelling to Mars

from the Martian surface with ease. The point is that the
technology for getting off Mars with a rocket is well in
hand, the engines, fuels, and structures we have today are
much more than up to the job, the trick is getting the
vehicles and all the fuel where you need it.

The 'Mars Direct' plan as advocated by Robert Zubrin calls for staging
and testing the return vehicles in advance of sending the manned
vehicles to Mars and also for the production of rocket fuel from CO2
on Mars itself with a small starter batch of hydrogen, as demonstrated
in his experiments here on earth. A lot of details are described in
his books and on the Mars Society web pages.

B. Debic.

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Can Nozomi enter Mars orbit? Jim Kingdon Space Science Misc 5 November 29th 03 08:06 PM
Mars Sample Return - The Real Space Race Alain Fournier Space Science Misc 4 November 20th 03 06:56 AM
Asteroid first, Moon, Mars Later Al Jackson Space Science Misc 0 September 3rd 03 03:40 PM
Let's go to Mars - but why come back? Mantra Space Science Misc 5 August 31st 03 10:00 PM
Mars trajectory problems? Bill Clark Space Science Misc 0 July 13th 03 11:25 PM


All times are GMT +1. The time now is 10:09 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.