Recent comments in /f/space

MoogProg t1_j60l2cw wrote

Well, it would be sync'd to UT/GMT but there will be differences in actual time between the two frames of reference. Set the Moon clock to UT/GMT running the same method of timekeeping as Geneva, they will drift apart from each other due to the relativistic effects of gravity. How that gets negotiated will be interesting. The Moon and Mars have their own time, no matter what 'zone' we apply to keep track of things. Crazy stuff.

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LitLitten t1_j60kx56 wrote

I wonder if inevitably the best approach will end up being taking advantage to some of the darkest craters and outfitting them as nuclear reactor heat sinks.

Could feasibly (?) bore a surface-subsurface tunnel for management from within the crater for necessary lab and maintenance habitation. Connect to other craters in this manner for production and so forth.

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Philip_Jay_Fryy t1_j60kaeg wrote

The Case For Mars - by Robert Zubrin

Expanded on from a research paper he helped wright. A Case for Mars is goes through a detailed mission plan for a cost effective crewed mission to Mars only using technology available in the 1990's

Some sci-fi books I like:

The Martin - Andy Weir

The Expanse series - James S.A. Corey

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Thisus t1_j60gxhk wrote

A few possible answers:

  1. If a spacecraft is orbiting a planet, each flyby of a moon is setting up the subsequent flybys. There are very precise conditions that they need to hit at each encounter for the whole trajectory to work.
  2. For a spacecraft in orbit about a planet, it is costly to capture at one of the moons. Due to propellant constraints, if you capture into orbit at one of the moons you are generally staying there (e.g. getting better science at Io but sacrificing science at Ganymede, Callisto, Europa, and Jupiter itself).
  3. Some moons are very difficult to have a spacecraft in orbit. Jupiter, for example, has a very hazardous radiation environment (especially for the electronics on board the spacecraft). Even if we had a dedicated Io mission, it might be better to have a series of flybys instead of orbiting the body because the spacecraft could live longer and return more data.
  4. While being closer to a body generally will provide better resolution, it may not be required to meet the mission's science objectives. Also, the closer you approach a moon the faster you fly past it. You may actually get more data by having a lower resolution over a longer time span. It all comes down to what cameras and other instruments are on the spacecraft.
  5. You have to keep in mind the scale of the solar system. Several hundred (or even thousand) kilometers away from a body is still pretty dang close. Even if you are 3,000 km away from Io, that's still less than 1/100 the distance from the Earth to the Moon. There's a lot of science you can do from there.
  6. Due to navigational uncertainties, there is a limit to how close a spacecraft is allowed to approach each body. They like to be 110% sure that their 100+ million dollar spacecraft isn't going to become a new crater on Europa. Also, some moons (like Europa) may harbor life and have additional protections which can constrain your flyby distance.
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dittybopper_05H t1_j60euza wrote

You only need time zones if by definition you have access to daylight, and you depend on daylight. People who don't need that, like submarine crews, just run on an arbitrary time.

There's no reason why the entire Moon can't be on the same time zone, as the lunar day isn't 24 hours anyway, it's more like 27 days, and pretty much everyone will be underground.

So everyone will be on Coordinated Lunar Time, which will be abbreviated to LTC in a compromise with the French speaking world.

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Hot_Egg5840 t1_j60dobt wrote

The closer to the object you are orbiting, the faster you need to go to stay in orbit. The faster you move, the more of an issue image blur is. Distant objects don't get much light. That means camera shutters need to stay open longer times, which also adds to blur. Yes, you would get better detail but it becomes useless because all the pixels are blurred.

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aztronut t1_j60d46i wrote

When the trade is between coverage and orbital altitude, coverage wins and closer is not necessarily better. It is also more dangerous to insert a spacecraft into such a close orbit, where it is also affected more by the perturbations induced by the body it is orbiting and thus more difficult to navigate. Look into the history of the MESSENGER mission and you'll see that once complete coverage of the surface was obtained the orbit was lowered progressively until impact was achieved at end of life, this seems to be the scenario you are asking for.

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oalfonso t1_j60b7o7 wrote

Take this with a pinch of salt because I don't remember when I heard it or read it. Juno originally wasn't going to have any cameras and NASA PR department demanded them to have something to show to the public because unless you are a scientist the telemetry data alone is not cool.

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VulpesIncendium t1_j60b4xh wrote

IMO, they should just permanently stick with GMT on the Moon. Maybe it could have its own designation (Moon standard time?), but whatever that is, it should simply match the current GMT. Anything else would get too complicated to reconcile with Earth schedules.

Now, a permanent Mars colony is where time zones would really get tricky. The Martian day/night cycle is close enough to Earth's that it would be awkward to force an Earth based 24 hr schedule there.

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NearABE t1_j60assd wrote

Earth will be overhead for all of the near side. Using the apparent location of the GMT line would add 49 minutes to every day. That allows time for sleeping in and generally relaxing.

The direct lazer communication lines would rise at the same time everyday. Geostationary satellites would eclipse at the same time everyday too.

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oalfonso t1_j60900b wrote

Juno main mission wasn't taking pictures, it was magnetosphere analysis to try to understand Jupiter's internal structure. The orbits were set for that mission, not pictures.

Also, any orbit on Jupiter and Saturn has to be carefully analysed to minimise the impact of the radiation on the spacecraft.

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PM-ME-YOUR-TECH-TIPS t1_j608c1u wrote

The closer you get to a sphere the less of its surface area you can see. If you want pictures as close to half the surface area you want, you need to go really far away. Infact, to see 50% of the surface area of any sphere, you need to go infinitely far away

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YesWeHaveNoTomatoes t1_j607oio wrote

If Io had been Juno's target, they would probably have calculated its trajectory and fuel needs to achieve either an actual orbit around Io or, if that wasn't possible, a closer flyby. But Juno's main target was Jupiter itself, so all photos of Jupiter's satellites were taken from the most fuel-efficient orbit around Jupiter.

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Billyconnor79 t1_j607iz7 wrote

Keep in mind that Io is not just hanging there in deep space with no other bodies around. It’s subject to intense gravity from Jupiter and even the other three Galilean moons that impact the shape and proximity of the orbits that can be plotted.

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djmustturd t1_j607dh3 wrote

Spacecraft like Juno have very specific orbits to follow that are planned very far in advance in order to maximize their mission time. If, say, Juno swings too close to Io, it might get a gravity assist that ejects it from Jupiter, in which case it’s no longer very useful is it.

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