The paper explores ideal orbits for space-based interferometers

Ever since the invention of the telescope in 1608, astronomers have strived for bigger and better telescopes. When it comes to instruments for observing the sky, if you’re observing fainter galaxies or planets, a larger collector results in higher resolution and brighter images. A recent article by Takahiro Ito of the Institute of Space and Astronautical Science in Japan Published want arXiv The preprint server looks at different types of orbits around Earth, supporting multiple telescope systems called interferometers in different orbits.

There is a limit to the size of Earth-based telescopes, and they can become so large that they collapse under their own weight, so keeping images sharp is a constant battle. An alternative solution is to link multiple telescopes so they work together. These interferometers work well on Earth, but space-based instruments present more challenges. Ito’s study, which looks at different types of orbits, has an orbiter in favor of a space-based interferometer.

The concept of interferometry exploits the wave properties of light. The signal from the independent receivers (whether they be optical or other wavelengths) are combined and superimposed, artificially representing the telescope’s resolution equal to the distance between the two receivers. The real challenge with this technique is that the receivers must be positioned very precisely.

Currently one of the largest interferometers on Earth is ALMA, the Atacama Large Millimeter Array that, as its name suggests, monitors the sky at millimeter wavelengths. It can extend its receivers up to 16 km, but is dwarfed by the Event Horizon Telescope, an international effort to build a world-scale radio telescope interferometer. No matter how far we can go, the Earth is going to limit their size, so the solution – put them in space.

Space-based interferometers have further challenges. Put a telescope down on Earth and it usually stays there, but try to put a telescope in space and it’s going to take some serious engineering (which we don’t have right now) to keep them in a stable and accurate position. Engineering challenges aside, where do you put them?

Ito’s paper has been accepted for publication Astronomy & AstrophysicsIt looks at possible orbits where interferometers could be placed and concludes that maintaining an accurate position in a geocentric (Earth-centered) orbit is achievable.

There are effects on Earth’s orbit, for example, the gravitational effect of the Sun and Moon, which can disturb objects in orbit. The study showed that high-altitude orbits have smaller disturbances compared to low-altitude orbits. Regardless, with the right technology, these disturbances can be mitigated to facilitate precise control of space-based interferometers.