Observing Orbital Mechanics from the 2nd Focus of Earth's Orbit

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Discussion Overview

The discussion revolves around the hypothetical observations and challenges associated with a spacecraft stationed at the 2nd focus of Earth's orbit. Participants explore the potential for making useful measurements related to orbital mechanics, the feasibility of such a craft, and comparisons to existing and proposed spacecraft at Lagrange points.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions what useful observations could be made from the 2nd focus of Earth's orbit, suggesting the measurement of angles between the Earth, Sun, and spacecraft.
  • Another participant notes that the Earth's orbit is nearly circular, implying that this simplifies the analysis.
  • Some participants highlight that the two foci of Earth's orbit are not very far apart, suggesting that Lagrange points may offer more interesting observational opportunities.
  • There is a mention of existing satellites like SOHO at the L1 position and the upcoming James Webb Space Telescope at the L2 point, indicating interest in these locations for observation.
  • Concerns are raised about the maintenance and repair challenges of spacecraft at Lagrange points, with references to the engineering capabilities demonstrated in recent space projects.
  • Discussion includes speculation about the potential improvements in imaging from modern software for telescopes like Hubble, if positioned at L4.

Areas of Agreement / Disagreement

Participants express differing views on the practicality and usefulness of a spacecraft at the 2nd focus of Earth's orbit versus Lagrange points. There is no consensus on the best observational strategy or the feasibility of such a craft.

Contextual Notes

Participants express uncertainty regarding the specific physics and engineering challenges, such as fuel consumption for station keeping and hull temperature facing the Sun, which remain unresolved.

Dustin Maki
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TL;DR
If a spacecraft could keep station at the 2nd focus of Earth's orbit, what useful observations could be made?
If a hypothetical spacecraft could keep station at the 2nd focus of Earth's orbit, what useful observations could be made?

Each minute sees a new solar triangle Earth Sun Craft (ESC). Swept area remains constant, as should length SC, and length CE + ES.
With the Sun as our point source, and instrumentation at Earth and Craft we should be able to precisely measure angles between each of our objects.

Might the sum of those angles exceed 180degrees?

Presumably the craft could be repositioned at the 2nd focus of other solar orbits. Could there be a better vantage point to observe orbital mechanics?

If you had access to a craft with this capability, what would you want to do with it?

What physics and engineering challenges are the highest barriers to making such a craft real?
For example; assuming Raptor Vacuum engines are used for station keeping, approximately how many kilograms of methane and LOX would would be consumed for that purpose in 1 Earth year.

What is the expected hull temperature facing the Sun at that point in space?

Sorry for all the questions and no answers. They just occurred to me and I thought others might like to know the answers as well.
 
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Dustin Maki said:
Summary:: If a spacecraft could keep station at the 2nd focus of Earth's orbit, what useful observations could be made?
The Earth's orbit is nearly circular. Set the controls for the heart of the Sun!
 
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PeroK said:
The Earth's orbit is nearly circular. Set the controls for the heart of the Sun!
Well that makes it rather simple then. That is the problem with lay physics, little appreciation for the scale of things.
 
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As PeroK says, the two foci of the Earth's elliptical orbit are not very far apart.

Lagrange points are more intetesting. We have at least one satellite, SOHO, at the L1 position. Satellites at L4 or L5 would give us a nice perspective on the Sun for day to day observation.
 
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@Ibix SOHO was at the back of my mind while thinking of this. So change the question such that Craft C is at L4.
 
The soon to come James Webb Space Telescope will be located at the L2 Lagrange point.
 
@anorlunda those would be much more acute triangles than L4, but easier location to reach I suppose.
 
L points are ideal for lots of things. Unfortunately, maintenance and repair are difficult. Recent Space projects have demonstrated just how good our Engineering can be.

Hubble at L4 would still be as myopic as it started. But modern image processing software would probably have done a lot to improve the images.
 
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sophiecentaur said:
L points are ideal for lots of things. Unfortunately, maintenance and repair are difficult. Recent Space projects have demonstrated just how good our Engineering can be.

Hubble at L4 would still be as myopic as it started. But modern image processing software would probably have done a lot to improve the images.
That is why I labelled the James Webb Space Telescope as really bold and daring. It can never be visited by repair missions.

Their major weapon would be the ability to upload revised software. Look at how well that worked for Voyager 1&2.
 
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