Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > sci.physics.relativity > #377232 > unrolled thread

How long does it take to get to Mars?

Back to article view | Back to sci.physics.relativity

Contents

  How long does it take to get to Mars? The Starmaker <starmaker@ix.netcom.com> - 2016-02-26 09:55 -0800
    Re: How long does it take to get to Mars? The Starmaker <starmaker@ix.netcom.com> - 2016-02-26 09:56 -0800
      Re: How long does it take to get to Moon/Mars? "a425couple" <a425couple@hotmail.com> - 2016-02-26 11:00 -0800
      Re: How long does it take to get to Mars? The Starmaker <starmaker@ix.netcom.com> - 2016-02-27 10:56 -0800
    Re: How long does it take to get to Mars? scott@slp53.sl.home (Scott Lurndal) - 2016-02-26 19:50 +0000
    Re: How long does it take to get to Mars? Sylvia Else <sylvia@not.at.this.address> - 2016-02-28 12:19 +1100
      Re: How long does it take to get to Mars? Emigdio Sophronius <emigg@augustvisitors.org> - 2016-02-28 13:50 +0000
        Re: How long does it take to get to Mars? Emigdio Sophronius <emigg@augustvisitors.org> - 2016-02-28 14:00 +0000
        Re: How long does it take to get to Mars? Sylvia Else <sylvia@not.at.this.address> - 2016-02-29 11:22 +1100
      Re: How long does it take to get to Mars? Wolffan <AKWolffan@gmail.com> - 2016-02-28 17:45 -0500
        Re: How long does it take to get to Mars? "Paul B. Andersen" <relativity@paulba.no> - 2016-02-29 21:07 +0100

#377232 — How long does it take to get to Mars?

I'm a little confused...

How long does it take to get to Mars?


I'm not sure if it is three months or three days or three seconds...

i think it starts with a three..

[toc] | [next] | [standalone]

#377233

The Starmaker wrote:
> 
> I'm a little confused...
> 
> How long does it take to get to Mars?
> 
> I'm not sure if it is three months or three days or three seconds...
> 
> i think it starts with a three..



how long does it take to get to the Moon?

[toc] | [prev] | [next] | [standalone]

#377243 — Re: How long does it take to get to Moon/Mars?

"The Starmaker" <starmaker@ix.netcom.com> wrote in message...
> The Starmaker wrote:
>> I'm a little confused...

> how long does it take to get to the Moon?

Well, Apollo_17 to put men on the moon,
was launched at 12:33 am EST on December 7, 1972.
"At approximately 2:47 pm EST on December 10, the Service
Propulsion System engine on the Command/Service Module
ignited to slow down the CSM/Lunar Module stack into lunar orbit.
-- The LM touched down on the lunar surface at 2:55 pm EST on
December 11. "
https://en.wikipedia.org/wiki/Apollo_17

So, 3 or 4 days should not be argued with.


>> How long does it take to get to Mars?

Well, the unmanned
Mariner 4  was launched 28 November 1964
and arrived at Mars 14 July 1965  and did a Flyby.
Mariner 6, launched 25 February 1969  and
flew pas Mars on 31 July 1969.

Mariner 9  launched 30 May 1971, arrived 13 November 1971
and was a  Success (first successful orbit).
https://en.wikipedia.org/wiki/Exploration_of_Mars

Proposed Human flight seems slower.
https://en.wikipedia.org/wiki/Human_mission_to_Mars
"The energy needed for transfer between planetary orbits, or "∆V", is lowest 
at intervals fixed by the synodic period. ---- 
Several types of mission plans have been proposed, such as the opposition 
class and conjunction class,[10] or the Crocco flyby.[11] The lowest energy 
transfer to Mars is a Hohmann transfer orbit; a mission to Mars using Hohman 
transfer involves an approximately 9 month travel time from Earth to Mars, 
about five hundred days at Mars to wait for the transfer window to Earth, 
and a Hohmann transfer of about 9 months to return to Earth.

Shorter Mars mission plans have round-trip flight times of 400 to 450 
days,[12] but requiring a higher energy. A fast Mars mission of 245 days 
round trip could be possible with on-orbit staging.[13] In 2014 Ballistic 
capture was proposed, which may reduce fuel cost and provide more flexible 
launch windows compared to the Hohmann.[14]

In the Crocco grand tour, a "humanned" spacecraft would get a flyby of Mars 
and Venus for under a year in space.[15] Some flyby mission architectures 
can also be extended to include a style of Mars landing with a flyby 
excursion lander spacecraft.[16] Proposed by R. Titus in 1966, it involved 
extending a flyby mission with a short stay lander.[16] Basically, a short 
stay lander-ascent vehicle would separate from a "parent" Earth-Mars 
transfer prior to its flyby of Mars.[16] The Ascent-Decent lander would 
arrive sooner and either go into orbit around Mars or land, and depending on 
the design offer perhaps 10–30 days before it needed to launch itself back 
to the main transfer vehicle.[16] (see also Mars flyby)

[toc] | [prev] | [next] | [standalone]

#377362

The Starmaker wrote:
> 
> The Starmaker wrote:
> >
> > I'm a little confused...
> >
> > How long does it take to get to Mars?
> >
> > I'm not sure if it is three months or three days or three seconds...
> >
> > i think it starts with a three..
> 
> how long does it take to get to the Moon?



http://www.techtimes.com/articles/136939/20160227/flying-to-mars-in-just-30-minutes-may-be-possible-using-laser-propulsion-system.htm


30 minutes to Mars????




how long does it take to get to the Moon? my math is not tooo goood.

[toc] | [prev] | [next] | [standalone]

#377255

The Starmaker <starmaker@ix.netcom.com> writes:
>I'm a little confused...
>

No shit!

[toc] | [prev] | [next] | [standalone]

#377379

On 27/02/2016 4:55 AM, The Starmaker wrote:
> I'm a little confused...
>
> How long does it take to get to Mars?
>
>
> I'm not sure if it is three months or three days or three seconds...
>
> i think it starts with a three..
>

There no particular answer. A sufficiently capable technology could get 
a person to the moon in 5 hours at a constant 1g acceleration (i.e. 
comfortably). The same acceleration would get a person to Mars in a 
couple of days (when Mars is closest to the Earth).

Higher accelerations give low journey times (but in less comfort).

However, we lack the technology to maintain such accelerations over 
extended periods.

Sylvia.

[toc] | [prev] | [next] | [standalone]

#377398

Sylvia Else wrote:

> On 27/02/2016 4:55 AM, The Starmaker wrote:
>> I'm a little confused...How long does it take to get to Mars?
>> I'm not sure if it is three months or three days or three seconds...
>> i think it starts with a three..
>>
> There no particular answer. A sufficiently capable technology could get
> a person to the moon in 5 hours at a constant 1g acceleration (i.e.
> comfortably). The same acceleration would get a person to Mars in a
> couple of days (when Mars is closest to the Earth).
> Higher accelerations give low journey times (but in less comfort).
> However, we lack the technology to maintain such accelerations over
> extended periods. Sylvia.

Amazing, the question is about something completely else. It reveals your 
standard in Physics and general in Science. The duration of journey 
depends on the position of Mars wrt Earth, as it orbits the Sun NOT 
synchronous to Earth. Remember to buy a brain, lady, when you walk close 
to a brain-marked.

[toc] | [prev] | [next] | [standalone]

#377399

Emigdio Sophronius wrote:

> Sylvia Else wrote:
> 
>> On 27/02/2016 4:55 AM, The Starmaker wrote:
>>> I'm a little confused...How long does it take to get to Mars?
>>> I'm not sure if it is three months or three days or three seconds...
>>> i think it starts with a three..
>>>
>> There no particular answer. A sufficiently capable technology could get
>> a person to the moon in 5 hours at a constant 1g acceleration (i.e.
>> comfortably). The same acceleration would get a person to Mars in a
>> couple of days (when Mars is closest to the Earth).
>> Higher accelerations give low journey times (but in less comfort).
>> However, we lack the technology to maintain such accelerations over
>> extended periods. Sylvia.
> 
> Amazing, the question is about something completely else. It reveals
> your standard in Physics and general in Science. The duration of journey
> depends on the position of Mars wrt Earth, as it orbits the Sun NOT
> synchronous to Earth. Remember to buy a brain, lady, when you walk close
> to a brain-marked.

And here is the proof.

NASA PLANNING HUMAN SPACE OUTPOST 
https://www.youtube.com/watch?v=nqY1ibpQ08o

For instance, the duration for humans to land on the Moon is about a 
minimum of 60 Years (Earth time).

Russia just announced that it's sending humans to the moon
http://uk.businessinsider.com/russia-announces-first-manned-mission-to-moon-2015-10?r=US&IR=T

[toc] | [prev] | [next] | [standalone]

#377452

On 29/02/2016 12:50 AM, Emigdio Sophronius wrote:
> Sylvia Else wrote:
>
>> On 27/02/2016 4:55 AM, The Starmaker wrote:
>>> I'm a little confused...How long does it take to get to Mars?
>>> I'm not sure if it is three months or three days or three seconds...
>>> i think it starts with a three..
>>>
>> There no particular answer. A sufficiently capable technology could get
>> a person to the moon in 5 hours at a constant 1g acceleration (i.e.
>> comfortably). The same acceleration would get a person to Mars in a
>> couple of days (when Mars is closest to the Earth).
>> Higher accelerations give low journey times (but in less comfort).
>> However, we lack the technology to maintain such accelerations over
>> extended periods. Sylvia.
>
> Amazing, the question is about something completely else. It reveals your
> standard in Physics and general in Science. The duration of journey
> depends on the position of Mars wrt Earth, as it orbits the Sun NOT
> synchronous to Earth. Remember to buy a brain, lady, when you walk close
> to a brain-marked.
>

Did you have some difficulty with the "when Mars is closest to the Earth"?

Or are you referring to my response re the moon, which was a response to 
the OP's reply to his own post.

Perhaps reading more, and writing less, would serve you well.

Sylvia.

[toc] | [prev] | [next] | [standalone]

#377449

On 27 Feb 2016, Sylvia Else wrote
(in article <djf092FhgvnU1@mid.individual.net>):

> On 27/02/2016 4:55 AM, The Starmaker wrote:
> > I'm a little confused...
> > 
> > How long does it take to get to Mars?
> > 
> > 
> > I'm not sure if it is three months or three days or three seconds...
> > 
> > i think it starts with a three..
> 
> There no particular answer. A sufficiently capable technology could get
> a person to the moon in 5 hours at a constant 1g acceleration (i.e.
> comfortably). The same acceleration would get a person to Mars in a
> couple of days (when Mars is closest to the Earth).
> 
> Higher accelerations give low journey times (but in less comfort).
> 
> However, we lack the technology to maintain such accelerations over
> extended periods.
> 
> Sylvia.

hmm... let’s see...

s = u*t + 0.5 *a*t^2

s is displacement under accel
u is initial vel
a is accel
t is time under accel

set s to 400,000 km. Yes, I know that that’s not quite right, but it’s 
good enough for government work and it makes for easy calculations.
set a to 10 m/s/s. Yes I know, but see above.
set u to 0. See above.

for continuous accel, there needs to be aceel to halfway, then turnover and 
decel the rest of the way. New s = 200,000 km.

s = 200,000 km = 2 * 10^8 m = 0*t + .5*10*t^2

which means that 4 * 10^8 = 0 + 10 *t^2
t^2 = 4 * 10^7
t = 6324.6 s = 1.756 hours.

That’s t to turnover. t for entire run is 3.51 hours.

of course, getting a rocket with a mission delta-v of 6324.6 * 2 * 10 = 126.5 
km/s might be a tad difficult. (v = u + a * t, and all that.)

If someone wants to get there in half the time, they’d need four times the 
accel. This would be Bad.

Mars at one gee would be considerably more difficult than Luna at one gee, 
and at four gees would be very bad indeed..

[toc] | [prev] | [next] | [standalone]

#377507

On 28.02.2016 23:45, Wolffan wrote:
> On 27 Feb 2016, Sylvia Else wrote
> (in article <djf092FhgvnU1@mid.individual.net>):
>
>> On 27/02/2016 4:55 AM, The Starmaker wrote:
>>> I'm a little confused...
>>>
>>> How long does it take to get to Mars?
>>>
>>>
>>> I'm not sure if it is three months or three days or three seconds...
>>>
>>> i think it starts with a three..
>>
>> There no particular answer. A sufficiently capable technology could get
>> a person to the moon in 5 hours at a constant 1g acceleration (i.e.
>> comfortably). The same acceleration would get a person to Mars in a
>> couple of days (when Mars is closest to the Earth).
>>
>> Higher accelerations give low journey times (but in less comfort).
>>
>> However, we lack the technology to maintain such accelerations over
>> extended periods.
>>
>> Sylvia.
>
> hmm... let’s see...
>
> s = u*t + 0.5 *a*t^2
>
> s is displacement under accel
> u is initial vel
> a is accel
> t is time under accel
>
> set s to 400,000 km. Yes, I know that that’s not quite right, but it’s
> good enough for government work and it makes for easy calculations.
> set a to 10 m/s/s. Yes I know, but see above.
> set u to 0. See above.
>
> for continuous accel, there needs to be aceel to halfway, then turnover and
> decel the rest of the way. New s = 200,000 km.
>
> s = 200,000 km = 2 * 10^8 m = 0*t + .5*10*t^2
>
> which means that 4 * 10^8 = 0 + 10 *t^2
> t^2 = 4 * 10^7
> t = 6324.6 s = 1.756 hours.
>
> That’s t to turnover. t for entire run is 3.51 hours.

OK.

Since this is s.p.relativity, an interesting question would be:
How much shorter would the time measured by the traveller
be compared to the time measured in the rest frame of the Earth?

Let T be the time as measured in the rest frame of the Earth,
and let tau be the time measured by the traveller.

Using the equations in:
https://paulba.no/pdf/TwinsByMetric.pdf
and ignoring the influence of Earth's gravitation give the answers:

Trip to the Moon, distance 3.844E8 m, with 1 g (9.81 m/s^2)
acceleration, changing direction of acceleration halfway:
T = 3.47759632 hours,  tau = 3.47759630 hours,  (T - tau) = 88 us

Trip to Mars, distance 5.6E10 m, with 1 g acceleration,
changing direction of acceleration halfway:
T = 1.748923 days, tau = 1.748921 days, (T - tau) = 154 ms

Not a big difference, but measurable (in principle).

(The numbers of digits are what they have to be to see the difference,
  and are much higher than the precision of the input data.
  That means that the absolute precision of T and tau is much less
  than the number of digits indicates. The precision of T-tau is
  about as good as the number of digits shown, though.)


-- 
Paul

https://paulba.no/

[toc] | [prev] | [standalone]

Back to top | Article view | sci.physics.relativity

csiph-web