Travel time between planets

[Evex]

I was reading the Gundam F90 manga and this got me wondering how long would it take to travel between Earth to Mars, Earth to Jupiter and Mars to Jupiter ? I know the Jupiter Fleet makes the trip between Earth and Jupiter rather regularly, but looking at the old archive of gundam official didn't give specifics of travel time of the fleet.

In Gundam F90 The 13 independent mobile fleet starts at a distance of 15,200,000 kilometers from Mars. By the time they reach 5,460,000 kilometers they are 3 months and 23 days away from Mars. The fleet itself is made of one Callium Class, two Salamis Class, two unspecified resupply ships, three Irish Class and three L-233 type minesweeper ships. This of course is around UC 120s, which is the time period I would like to stay in or around.

I also did some research on my own to see what the distance between each planet is, but the only site I could find is a site that listed the average distance between each planet.

Average distance between Mars and Jupiter 550,520,165 km
Average distance between Mars and Earth 077,790,893 km
Average distance between Earth and Jupiter 628,311,058 km

Link to site where I got the numbers from: Planetsedu.com

[MythSearcher]

I was reading the Gundam F90 manga and this got me wondering how long would it take to travel between Earth to Mars, Earth to Jupiter and Mars to Jupiter ? I know the Jupiter Fleet makes the trip between Earth and Jupiter rather regularly, but looking at the old archive of gundam official didn't give specifics of travel time of the fleet.

In Gundam F90 The 13 independent mobile fleet starts at a distance of 15,200,000 kilometers from Mars. By the time they reach 5,460,000 kilometers they are 3 months and 23 days away from Mars. The fleet itself is made of one Callium Class, two Salamis Class, two unspecified resupply ships, three Irish Class and three L-233 type minesweeper ships. This of course is around UC 120s, which is the time period I would like to stay in or around.

I also did some research on my own to see what the distance between each planet is, but the only site I could find is a site that listed the average distance between each planet.

Average distance between Mars and Jupiter 550,520,165 km
Average distance between Mars and Earth 077,790,893 km
Average distance between Earth and Jupiter 628,311,058 km

Link to site where I got the numbers from: Planetsedu.com

If I recall right, its about 4 years round trip from Earth to Jupiter around OYW, and got faster after that.
The problem of this in real life is that the planets are not only moving and the positions are constantly changing, so you always have different times of a round trip or you'll have a really long waiting time stationary at one point.
Also, the path you take differs as well. If you get to use Venus as a gravity slingshot when going from Earth to Mars, you can get there faster, but again, Venus is moving and not always there.
The back trip, if under a similar distance and direction, usually is faster since you can a little boost with the Sun's gravity(you are falling towards the Sun)

So there's no quick and absolute answer to your question, in a more real life situation, you normally want to save propellant when travelling that far and thus usually use the Hohmann transfer orbit, so it will be a bit easier to do calculations on the actual time needed.
The UC universe, however, seems to be utilizing touchships to a certain degree(well, maybe half hohmann half touchship) so it will be much harder to do the calculations.

[Brave Fencer Kirby]

What you're looking for is called the Hohmann transfer orbit -- basically, it's the "cheapest" (least propellant required) way to get between two different places that are orbiting the same thing. The trick is, they're only available at certain times, since they require the places you're travelling between to be in a certain position relative to each other.

Here's a bunch of examples. A Hohmann orbit from Earth to Jupiter, for example, takes about 2 years and 9 months, and an opportunity for one comes up about every 13 months. (That means a round trip actually takes a little over 6 years, since you have a 2 year 9 month trip there, then you have to wait around 7 months for the departure window to come around again, then you have another 2 year 9 month trip back.) Between Earth and Mars is a 8.5 month trip with an opportunity every 2 years, and between Mars and Jupiter is a 3 year trip every 2 years 3 months.

[Evex]

I see. Another reason I wanted to know this is that I'm trying to figure out if there were colonies around Mars what the social climate would be like. Would they end up like Jupiter where everything was strictly controlled, or would they end up with different social views. For example Callisto is one of Jupiters moons and if memory serves me correctly is covered in ice. This is a potential source of water for both the Mars and Jupiter colonies.

I was also thinking of how Universal century technology might be used to colonize mars surface. There are the methods used to colonize the moon, but I can't remember if any of the lunar cities are actually domed. If not I might have to combine a few different universes Mars technology to get a some what plausible colonization concept.

It also now explains why the Jupiter fleets ships are so large. They need to carry enough helium 3 to last for four years, until the next ship arrives.

[Raikoh]

I could bring this to the table: in Crossbone Gundam: Steel Seven, they manage to make it from Earth to Jupiter in under a week. They need the latest technology, the Speed King (which has prototype Wings of Light) to pull it off, and they could only bring seven Mobile Suits along, but it's possible. They also mention that by that point in time, it usually takes a few months to make the trip.

[MythSearcher]

What you're looking for is called the Hohmann transfer orbit -- basically, it's the "cheapest" (least propellant required) way to get between two different places that are orbiting the same thing. The trick is, they're only available at certain times, since they require the places you're travelling between to be in a certain position relative to each other.

Here's a bunch of examples. A Hohmann orbit from Earth to Jupiter, for example, takes about 2 years and 9 months, and an opportunity for one comes up about every 13 months. (That means a round trip actually takes a little over 6 years, since you have a 2 year 9 month trip there, then you have to wait around 7 months for the departure window to come around again, then you have another 2 year 9 month trip back.) Between Earth and Mars is a 8.5 month trip with an opportunity every 2 years, and between Mars and Jupiter is a 3 year trip every 2 years 3 months.

That's the problem here, in UC, they are not fully using Hohmann Transfer orbit, and a round trip to Jupiter from Earth is just roughly 4 years and 2 months.
In the official timeline, the 1st Zeon Jupiter fleet started off in Oct, 0070, and returned Dec, 0074.(With heavy causalties)

[MythSearcher]

I could bring this to the table: in Crossbone Gundam: Steel Seven, they manage to make it from Earth to Jupiter in under a week. They need the latest technology, the Speed King (which has prototype Wings of Light) to pull it off, and they could only bring seven Mobile Suits along, but it's possible. They also mention that by that point in time, it usually takes a few months to make the trip.

If I recall right, Judah's departure from Earth to Jupiter after ZZ(0089) is already only like a 9 months round trip.

[Brave Fencer Kirby]

If that's the case, then the only answer is "whatever the writers want it to be", then -- without Hohmann orbits, we really have no reference point, so it's entirely up to them to invent how long they want things to take.

[latenlazy]

It's entirely plausible that by UC they aren't resource limited enough to be constrained to Hohmann orbits. In fact, for something with as much economic importance as helium fuel, profit optimization may dictate that a less fuel efficient route by taken in order to meet market demand. Keep in mind that the Jupiter Energy Fleet's operations aren't solely in the domain of physics problems. Economic viability matters just as much.

[Brave Fencer Kirby]

If the additional revenue from taking a faster orbit (and thus selling more loads of H-3) was greater than the additional cost of taking them, then yeah, that could be the case. Unfortunately, we really have no way of judging any of that.

[Jacob111]

Thanks all i am newbie here got some interesting information thanks

[Nebfer]

Ah Something I have some dealings with...

I don't think Gundam is using purely torch ships, or at the lest ones with a lot more limitations than one often sees, as you will see at even at a rate of 1 meter per second can get you to places quite fast if you can use it for weeks on end.

Opens up his travel times file that I made for Battletech a few years back
If you had the capability to perform a acceleration and then decelerate burn for weeks on end, before running out of fuel....

400,000 km (earth to the moon) will take at
.1G 11.22 Hours (B-tech Jumpships station keeping drive)
.5G 5.02 Hours
1G 3.55 Hours
2G 2.5 Hours
3G 2.05 Hours (typical B-tech Aerospace fighter with 10 tons of fuel is capable of doing this)
4G 1.77 Hours
12.5Gs 1 Hour

Things to note: pulling 2 or 3Gs for more than a Day is going to do bad things for a crew with out the tech to cancel out the acceleration, and doing 12ish Gs for a minute or so will cause most pilots to pass out with G-suits on.

1.5 million KM (Earth to Sun L1 point, Note in B-tech L1 points are FTL jump nodes)
.1G 21.7 Hours
.5G 9.7 Hours
1G 7.5 Hours
2G 4.9 Hours
3G 4 Hours

Mars
228 million KM (rough avg distance of Earth to Mars which is 56 to 400 million km depending on the orbits)
.1G 12.6 Days
.5G 5 Days
1G 3.5 Days
2G 2.5 Days
3G 2 Days
12.5G 1 Day

at 56 million km it's
.1G 5.5 Days
.5G 2.5 Days
1G 1.8 Days

at 400 million km
.1G 14.8 Days
.5G 6.6 Days
1G 4.7 Days

Now to reach Jupiter, Jupiter is roughly 790,000,000 km away (~avg. distance from earth, min is about 590 million km max is 970 million)
.1G 20.8 Days
.5G 9.3 Days
1G 6.6 Days

For reference battletech the Jump point is 10 AU out (1.5 billion km, and just past Saturn's orbit) and takes them 9 days to reach it at 1G.

As one can see even relatively slow acceleration rates like .98 meters per second (1/10th of 1G) you can reach Jupiter in under a month (~23 days in fact). As such Gundam it seems still uses "short duration" burns it's just that they have a lot higher ISP than we do.

[MythSearcher]

Ah Something I have some dealings with...

I don't think Gundam is using purely torch ships, or at the lest ones with a lot more limitations than one often sees, as you will see at even at a rate of 1 meter per second can get you to places quite fast if you can use it for weeks on end.

I must explain what I said in more detail.

If its within the Earth Sphere, UC post OYW-ships seems to be rather like torch ships.
(Pre-OYW ships has travelling time closer to Hohmann transfer orbit.)
But once beyond that, it seems like they are not constantly giving thrust, but at the same time travelling much faster than Hohmann transfer orbits.

Either they are thrusting at a really low rate(to save propellant at a higher efficiency) or they carry some sort of stage booster that keeps thrusting for a while to gain more speed before burning out.

[Sabersonic]

I'm under the impression, Post-OYW at the very least, that the thermonuclear fusion drives of the UC era are not true Torch Drives but rather Demi-Torch Drives. Or rather they have the potential to be torch drives but they don't have the space required for all the remass needed for the full burn to the skew flip portion of the Brachistochrone Orbit (Atomic Rockets details here). Rather, they do a rocket burn for a good chunk of the approach towards the mid-point of the orbit, and then coast the rest of the way until they reach the deceleration portion of the arrival. All within the DeltaV of the spacecraft in question.

[MythSearcher]

I'm under the impression, Post-OYW at the very least, that the thermonuclear fusion drives of the UC era are not true Torch Drives but rather Demi-Torch Drives. Or rather they have the potential to be torch drives but they don't have the space required for all the remass needed for the full burn to the skew flip portion of the Brachistochrone Orbit (Atomic Rockets details here). Rather, they do a rocket burn for a good chunk of the approach towards the mid-point of the orbit, and then coast the rest of the way until they reach the deceleration portion of the arrival. All within the DeltaV of the spacecraft in question.

Well, that seems to be what's going on for quite a while, to the extend where CDA showed a Zanzibar class with an extra booster for traveling from Axis to Earth sphere.

They act like demi-torch ships(didn't think of that term before) but I guess we never get any realistic depiction of them ever running out(or low) on propellant.(even after the long flight from Earth sphere to Axis, the EFSF ships seems to be doing normal combat pretty well with little to no propellant constraint. Pretty much just like what they are doing in the Earth sphere.)
I guess they dropped the boosters or external propellant tanks before battle.

UC does not have true torch ship in the sense until probably Minovsky Drive's invention.
But from then onwards, they likely have torch MSs which the only limitation is the pilot itself, not the propellant.

[Nebfer]

Humm been a while, as what we have seen for the canonical travel times and the pure torch drive travel time is posted, Gundam for the most part can not be using a pure torch drive, their travel times are much to long for that. 4+ months from Earth to Jupiter in the latter years either puts them at a rather slow acceleration rates (on the order of 3cm per second to reach Jupiter in 4 months), or they have a high acceleration impulse coupled with a long costing phase, the latter is far more likely.

Though interestingly the OP info indicates that it could take them a better part of a year to reach mars from earth...

AFAIK to reach Jupiter in roughly 4 months you need to be traveling at around 76km/s (~34km/s for 9 months, and ~12.5km/s for a 2 year trip), you can reach 76km/s in a bit over 2 hours at a acceleration rate of 9.8M/s (1G).

Though I do not think most gundam ships have that kind of Delta V on hand (supplied with extra fuel tanks sure it's possible they get that high). IIRC as unless this changes post CCA it still takes them a few days to get any where in earth system (I do not recall them getting to say the moon in an afternoon from earth orbit), which would imply a fairly low amount of Delta V available to them.

[MythSearcher]

Humm been a while, as what we have seen for the canonical travel times and the pure torch drive travel time is posted, Gundam for the most part can not be using a pure torch drive, their travel times are much to long for that. 4+ months from Earth to Jupiter in the latter years either puts them at a rather slow acceleration rates (on the order of 3cm per second to reach Jupiter in 4 months), or they have a high acceleration impulse coupled with a long costing phase, the latter is far more likely.

Though interestingly the OP info indicates that it could take them a better part of a year to reach mars from earth...

AFAIK to reach Jupiter in roughly 4 months you need to be traveling at around 76km/s (~34km/s for 9 months, and ~12.5km/s for a 2 year trip), you can reach 76km/s in a bit over 2 hours at a acceleration rate of 9.8M/s (1G).

Though I do not think most gundam ships have that kind of Delta V on hand (supplied with extra fuel tanks sure it's possible they get that high). IIRC as unless this changes post CCA it still takes them a few days to get any where in earth system (I do not recall them getting to say the moon in an afternoon from earth orbit), which would imply a fairly low amount of Delta V available to them.

4 months is way faster than hohmann transfer orbit though.(88% faster)
http://www.jgiesen.de/hohmann/index.html
Which takes 998 days.
Even the 4 year round trip before OYW seems about 25% faster than HTO.