Planet Seeker Telescope

The world's most powerful and affordable space-based interferometer

Introduction and Overview

Our mission is to seek out and colonise habitable exoplanets, of course, a number of organisations are aiming to do the same. However, the entire field of interstellar travel seems to be in something of a rut, with even the most optimistic projections of interstellar travel suggesting we will not set foot on a planet under an alien sun for at least a century, probably more. Yet is this truly an accurate assessment? We are of the opinion that it is not, that in fact interstellar travel could be achieved not within ten decades, but within a single decade.

This project is but the first, as we build a iron-hard case, that interstellar travel is in fact far easier, and far more near term, than anyone is currently expecting. Firstly, we must find a suitable exoplanet, no barren rock nor oversized comet will do, we must find a blue and green world potentially capable of supporting human life.

To this end, a new telescope operating on a colossal scale is needed, we have put together a design for just such a telescope, in fact a multipart telescope which we call the ‘Planet Seeker’, to be placed in a geostationary orbit, minimising the cost of deployment, and providing great stability, see below for an overview of the entire telescope.

The telescope will be a visible-light and possibly ultraviolet interferometer, able to directly image even quite small exoplanets with a substantially higher resolution than currently possible with traditional telescopes.

Three-quarters orthographic projection of the Planet Seeker, showing the position-keeping lasers

Another orthographic projection, showing how incoming light is collected and amplified

To minimise costs we have decided upon a ‘dumb’ array, consisting of hundreds of thousands of tiny, inexpensive thin-film plastic Fresnel zone plates, what the late Dr. Robert Forward referred to as ‘holographic tissue lenses’ forward1990rocheworld , which can be inexpensively mass produced at a fraction of the cost of conventional lenses doi:10.1021/acsnano.5b03165, allowing the production and launch of upwards of one million individual telescope units.

The basic design will be something like the Hypertelescope, proposed by Prof. Antoine Labeyrie in 1996 HypertelescopeOrg:2020, and which he and his team have steadily worked on for almost three decades. When completed, the array will consist of up to one million units, with a total collection area of over 700 square metres, a baseline of 100 kilometres or more, and an angular resolution of approximately 1.25 micro arc seconds.

For those who are not versed in the field: the resolution of a telescope is the angular size of the smallest resolvable object, a ‘higher’ resolution refers to a smaller minimal resolvable angle, therefore, an angular resolution of 1.25 micro arc seconds is an extremely high resolution, not a low resolution.

Once deployed, the Planet Seeker will possess a high enough resolution to successfully resolve features as small as 600 kilometres on a hypothetical planet in the Ran/Epsilon Eridani system, some 10.5 light years distant, as one example.

Science Goals and Objectives

The goals of the Planet Seeker are: (1) locate, characterise, and study from afar habitable worlds suitable for human colonisation, (2) investigate exoplanets for signs of intelligent activity, (3) study and locate, known and unknown distant bodies within our solar system, such as confirming and/or studying ‘Planet 9’, and (4) perform scientific study of innumerable cosmic phenomena.

An indefinite mission lifetime is intended, taking advantage of recent advances in space travel, such as the SpaceX Falcon 9, Falcon Heavy, Dragon, and Starship, to perform routine maintenance and upgrades on the interferometer array, and also the massively redundant number of the very simple individual ‘telescopes’, ensuring that the collective system can operate for years or decades with minimal maintenance.

Aside from its primary mission of seeking out habitable exoplanets, the Planet Seeker Interferometer will eventually also be available to perform many simultaneous ad-hoc studies of phenomena all over the sky, by making use of several light collectors and a spherical configuration to act as a multi-telescope, able to take images in many directions at once, much as Labeyrie’s proposed Hypertelescope HypertelescopeOrg:2020.

Properties of the Planet Seeker Interferometer

We expect the Planet Seeker to revolutionise astronomy and science in general, and we also expect certain social, political, cultural, and technological changes arising from discoveries the Planet Seeker will make.


With an angular resolution of 1.25 μas, the Planet Seeker could resolve features as small as continents or large islands, at such resolutions it will not only be possible to detect the signature of photosynthetic pigments like chlorophyll or an extraterrestrial equivalent, or other biologically-produced substances, but to resolve large-scale urbanisation. Below you can see on the left a blurred image simulating what Earth at night would look like from ten and half light years away, on the right is a simulated image of a heavily urbanised exoplanet at the same distance.

As you can see, the resolution of the Planet Seeker, while not high enough to make out smaller features, is more than sufficient to detect even the moderate levels of urbanisation on our planet.

Wandering Black Holes

Wandering or ‘rouge’ black holes with minimal or non-existent accretion disks could be more readily located, either via direct imaging, utilising the Planet Seeker's large collection area, or indirectly via observation of gravitational lensing, utilising the telescope's very high resolution.

The Nemesis hypothesis

The Nemesis hypothesis, originally put forward by palaeontologists David Raup and Jack Sepkoski in 1984 Raup801, proposes that Sol, our sun, has a low-mass binary companion orbiting on a 26 million year orbit with a semi-major axis of approximately 1 light year. Raup and Sepkoski noted a 26 million year interval between major extinction events, and suggested that there could be a small red or brown dwarf companion disturbing Oort cloud comets at regular intervals.

After decades of debate, in 2010 and 2013 Adrian Melott and Richard Bambach demonstrated that there is indeed a 26 or 27 million year periodicity to major extinction events 10.1111/j.1745-3933.2010.00913.x, i.e. extinctions occur at consistent 26 or 27 million year intervals. An independent study in 2021 by Michael Rampino, Ken Caldeira, and Yuhong Zhu RAMPINO2021101245, found that Earth has a 27.5 million year geological cycle, a ‘pulse’ as they termed it, where major volcanic events, and mass extinctions on the land and in the sea, appear to reoccur with an average interval of 27.5 million years.

However, Melott and Bambach also noted that a sharp peak in extinction events every 27 million years does not appear to be consistent with the Nemesis hypothesis Melott_2013. As they point out, because of Nemesis' great distance from the Sun, it is expected to have been perturbed by passing stars, and therefore should not produce a sharp peak in extinctions, but a more gradual one.

Regardless, the Planet Seeker will be able to answer this question definitively, first of all, a Jupiter-sized object (as Nemesis appears likely to be) at 1 light year is well within the Planet Seeker's imaging capabilities, secondly, with the Planet Seeker's large collection area, and despite the great distance of Nemesis, the very faint light from the Sun should be sufficient for imaging.

Trans-Neptunian Objects

With its high resolution and large collecting area, the Planet Seeker will be able to discover and image in detail many trans-Neptunian objects, from Eris, to Sedna, even a hypothetical planet that may exist at around 100 AU Holman_2016. Who knows, perhaps we'll find an Earth or Mars mass planet out there BRUNINI200232, an interesting thought.

Planet 9

First proposed in 2014 Sample:PlanetNine, Planet 9 is a hypothetical super-Earth orbiting the Sun, with an estimated mass of 5 to 10 times that of Earth BATYGIN20191Batygin_2016 and an estimated semi-major axis of 400 to 800 AU Brown_2016. We have analysed the possibility of imaging Planet 9, using a range of possible radii, ranging from somewhat greater than Earth's to a little less than that of Neptune, and with a range of albedos, and in most scenarios the Planet Seeker is able to image the planet with a relatively short observation period.

Principle of Operation

We are reaching the limit of what is possible with conventional and ground-based telescope designs, light pollution is ever-increasing, and conventional telescopes with large reflectors quickly become unwieldy. In order to achieve the greatest advances possible, we must instead turn to space-based interferometers.

Introduction to interferometers

Interferometers collect the feeble light from distant stars, planets, nebulae, black hole accretion disks (and in principle, Hawking radiation), and galaxies, amongst other celestial objects and phenomena, from multiple individual telescopes. A phased-locked laser beam is sent out to each of the many telescopes, where it interferes constructively and destructively with the incoming light, increasing the brightness whilst preserving contrast. By mixing with the out-going phased-locked beam, a certain frequency and phase signal is embedded within the now-amplified images, specifically the phase and frequency changes with the distance and time travelled.

The amplified images are sent on to a collector unit and combined, and by measuring and analysing the shift in both frequency and phase, a central computer can determine where in space and time each image was taken, sending this information to a ground-based supercomputer which processes the separate images into a single large image with a very high resolution, far higher than what any near-future mirror could achieve, and theoretically expandable to sizes that would be completely infeasible to manage with any single reflector.

This is analogous to taking the mirror out of a conventional reflecting telescope, and instead using several small mirrors, scattered around within the area the large single mirror formerly occupied, the image is just as sharp as before, despite the lack of a single continuous mirror.

Specific design of the Planet Seeker Interferometer

The design and operating principle of the Planet Seeker can be broken down into a few primary components.

Individual Telescopes

Very small and extremely low mass plastic Fresnel zone plates 2009ApSS.320..225KrefId0, or ‘holographic tissue-lenses’ forward1990rocheworld, mass produced, and easily suspended via laser light in a free-flying formation, against both Earth's gravitational pull and light pressure from the Sun HypertelescopeOrg:202010.1117/12.460844ognjen-atwater:2019.

By careful design of the lenses, a stable levitation can be achieved, as recent work on interstellar beamriders has illustrated Ying-Ju-Nelson-Swartzlander:2019ognjen-atwater:2019, other research, backed by ESA, successfully demonstrated laser propulsion of a 3 millimetre diameter graphene lightsail in microgravity GAUDENZI2020204, intriguingly, the researchers measured thrust an order of magnitude higher than expected from light pressure alone. Also recently, a new laser ablation manufacturing technique was developed by Zhao et al doi:10.1021/acsnano.5b03165, which opens the door for very inexpensive mass-production of the required lenses.

Single telescope/lens, offset laterally, the resulting uneven redirection of laser light produces a corrective force, returning the lens to centre

We have preliminarily decided on a visible-light, and possibly ultraviolet, telescope, the reasons are as follows:

Single telescope/lens, centred within opposing beams

(1) Visible and ultraviolet light requires smaller optical elements than near-infrared for the same image brightness, minimising cost

(2) Near-infrared lasers capable of producing a strong force on the tiny individual telescopes are inexpensive and commonly used Ying-Ju-Nelson-Swartzlander:2019ognjen-atwater:2019IndustrialLaserSolutions:2020

(3) A Sun-like star has a peak output in the middle of the visible spectrum, further maximising image brightness

(4) Visible light astronomy simply produces beautiful and inspiring imagery, where folks will know that the image they are seeing is something akin to what they would see with their naked eyes

The potential for stirring up enthusiasm cannot be overlooked, especially as this is one of the primary purposes of the Planet Seeker.


A two-part device, consisting of a housing for the CCDs used to collect incoming starlight, and a separate focusing element, made as a thin-film sheet using the same technique as used to manufacture the individual telescopes, and suspended via laser light a modest distance away.

This design allows for light to be collected from over 1 million individual telescopes, with the etched collecting lenses also functioning in reverse, as demonstrated by Khatri et al KHATRI201577, where a laser beam is sent out through one or more beam-splitters, and then focused to a ‘spot’ at each of the telescopes, making this component a combined Collector-Laser.

Internal measurement arms of a fixed and predetermined length allow comparison of incoming signals with a reference signal, permitting the all-important combination—interferometry—of the many images. See the work by Koechlin et al, on the ‘Fresnel interferometric imager’ 2009ApSS.320..225KrefId0, for more information about this type of lens as used to construct a telescope.

Laser focusing sheet, shown in a three-quarters orthographic projection

Side view of focusing sheet, showing how laser light is focused to the individual telescopes/lenses and the reflector


According to Labeyrie and the Hypertelescope team, a laser power of 3 milliwatts is required per telescope HypertelescopeOrg:202010.1117/12.460844, in order to levitate them against Earth’s pull and solar light pressure, this amounts to 3 kilowatts for 1 million telescopes, a relatively modest laser that is easily available, indeed, near-infrared lasers of this power level are frequently used in the manufacturing industry IndustrialLaserSolutions:2020.

The lenses are designed such that near-infrared laser light is unable to completely pass through, only partially penetrating and thereby producing a strong force on the tiny telescopes Ying-Ju-Nelson-Swartzlander:2019ognjen-atwater:2019.

Frequency-doubling material in the lenses converts some of the laser light into visible light Ou:92, that is able to interfere with incoming light in order to amplify the resulting image. Outgoing near-infrared laser light is focused to the individual telescopes by 1 million holographic lenses—etched into the focusing sheet—which, due to their unique properties, will also collect and refocus the incoming 400 to 700 nanometre wavelength starlight to a different spot than reflected 700+ nanometre, near-infrared laser light 2011IAPM...53...77W.

Later on, additional Collector-Lasers—or a larger focusing sheet and a higher power laser—can be added in order to support additional telescopes.


In order to suspend the telescopes, laser beams must act on the lenses from opposing directions, or else the laser light pressure will push the telescopes away, this requires a convex reflecting mirror to be placed opposite the Collector-Laser HypertelescopeOrg:202010.1117/12.460844.

Individual Telescope, offset longitudinally, the telescope/lens is no longer between the beam minima, with the uneven forces returning it to centre

Geostationary Orbit

Typically it is the Lagrange Points that are considered for telescope placement, permitting a view uninterrupted by Earth, or in the case of the Earth-Sun point L2, at least partially benefiting from Earth’s shadow. However, we plan on instead deploying the Planet Seeker to a geostationary orbit 10.1117/12.460844, providing a greater orbit stability, and lower launch costs, compared with the Lagrange Points. As the telescopes of the array are very low mass and easily suspended via laser beams, the only parts of the telescope that are in purely gravitational orbits are the Collector-Laser and the Reflector.

The easiest way then to achieve a stable arrangement is to place the Collector-Laser in a geostationary orbit some degrees ahead of, or behind, the Reflector, the telescopes are then suspended via laser light between the two, which will face each other. For comparison, if we wished to take advantage of Earth’s shadow over L2, we would find that over time the Collector-Laser and Reflector would tend to either drift toward the central region of L2, or away, requiring constant adjustment and therefore use of propellant, creating a limited lifetime for the telescope, or else continual refuelling.

By carefully angling the telescopes via adjustment of the outgoing laser beams, and by taking advantage of the new laser ablation manufacturing technique, to make lenses nearly without glare, we can avoid the problem of unwanted light from the Sun spilling into our images. Of course the telescope array would be unable to take images directly away or near the Sun, but that can be managed, such as by waiting for nightfall, and besides, over the course of a year nearly anywhere in the sky could still be imaged.

Image Processing Computer

A central computer aboard the Collector-Laser analyses the frequency and phase shift, as well as the angle, of returning laser beams, now carrying amplified images acquired by the individual telescopes, in order to determine where in space and time the image was taken. This information is beamed down to the ground, where a waiting supercomputer uses raytracing, as well as conventional digital interferometry techniques, to electronically produce a very high-resolution final image, even reproducing the effects of additional, more sophisticated optics, such as the ‘pupil densifier’ designed by Labeyrie et al 10.1117/12.460844, without the added mass and physical complexity such equipment would introduce.

Ground-Based Prototype

In advance of a space-based telescope array, a ground-based prototype can be developed and built within the next year or so. The prototype would be very minimalistic and non-disruptive to the environment, consisting of little more than an array of lenses on tripods. This way it can be built in a remote location, even in a designated wilderness park, without disturbing or altering the environment. Since 2011, the Hypertelescope team has been developing a similar prototype in the Alpes de Haute-Provence, in France HypertelescopeOrg:2020.

Ground-based prototype of the Planet Seeker Interferometer, shown situated in a hypothetical mountain valley

Several of the nearest star systems of a similar type to the Sun are located within the southern sky, such as Alpha Centauri, Ran (formerly known as Epsilon Eridani), Sirius, etc., therefore from the northern hemisphere they are either not visible at all or are visible only near the horizon, where there is greater atmospheric turbulence. It is for this reason, that we propose Central to South America as a possible location for the Planet Seeker prototype, specifically in a region with a mountainous landscape, helping to cut down on light pollution.

The following is a mathematical breakdown of the assumptions and concepts behind the Planet Seeker Interferometer.

Minimum angle, collection area, and testing assumptions

A telescope’s minimum resolvable angle θ is given by the equation

where λ is the wavelength of observed light in metres, D is distance between the farthest telescope elements (in metres), also known as ‘baseline’, and 1.22 is the Rayleigh criterion

Fleshing out the equation, for the sake of brevity we will assume a 500 nm wavelength (approximate average wavelength of visible light), and a 100 km baseline, with these assumptions we find that

or approximately . To get an idea what this means, first we need to find the kilometres covered within this angle at some specific distance. To do so, we must define a circle with a radius equal to the distance between the observed object (a planet in this case) and detector, and find the circumference C, this is given by the equation

where D is the distance to the observed object, which we will assume to be the distance to Ran (Epsilon Eridani) from the Solar system, approximately 10.47 light years . Solving for C, we find the circumference of our imaginary circle to be equal to . The distance covered by the telescope’s minimum resolvable angle, as found in equation 100-km-baseline-resolution, will equal some small section of this imaginary circle, the covered distance in metres Rm is given by the equation

where C is the circumference of an imaginary circle with a radius equal to the distance to Ran (Epsilon Eridani) as given by equation Circle-10.47-ly-radius, and θ is the resolution in radians of the telescope, given by 100-km-baseline-resolution, divided by 2π to give the fraction of a complete rotation occupied by this angle. Solving for Rm gives a distance of 604,545 meters, therefore, given a 100 kilometre baseline and a target wavelength of 500 nanometres, the smallest resolvable feature is approximately 600 kilometres.

To assess the feasibility of our design, we must also calculate the collecting area needed to produce a visible image. How many individual telescopes are necessary? Can many tiny telescopes easily achieve the collecting area of a larger single telescope, or does the system face quickly diminishing returns?

To this end we must find the number of photons reflected by a potentially Earthlike world orbiting a given star, which we will assume to be Ran (Epsilon Eridani), if Nγ is the approximate number of photons emitted per second by Ran then

where Lε is the luminosity of Ran (Epsilon Eridani), given in solar luminosity as 0.34L, as defined by the International Astronomical Union, that is, ribas:2009, and where Lγ is the energy of an average photon of light emitted by Ran, approximated here as the energy of a 500 nm photon . Solving for Nγ we find that the approximate number of photons emitted per second by Ran is equal to

Now we find the surface area of a disk with a radius equal to the mean radius r of our hypothetical Earthlike world, which we take to be equal to Earth’s mean radius, 6371 kilometres lide2000handbook, given by the equation

dividing this by the surface area of an imaginary sphere encompassing the Earthlike world’s orbit, given by the equation

where R is the radius of the orbit, taken as 1 astronomical unit IAU2012_English:2012, we now find the fraction of the radiant flux emitted by Ran intercepted by this planet, via

Next, to find the fraction of photons that will reach and reflect off the planet, we take the total number of photons emitted, as given by Eps-Eri-Photons-s and multiply it by the fraction given by Planet-radiant-flux-intercepted, and then multiply this value by the Bond albedo of the planet, giving us

where A is the Bond albedo of the hypothetical planet, which we assume here to be an Earthlike 0.3 earthfact:2020.

Now we can finally calculate the necessary collection area of the telescope array, as a baseline, we will assume one million telescope units, each with a 30 mm diameter, so

where r is the radius of each telescope unit.

As we can see, the total collection area of the array is 706.9 m2, now to find if this collecting area is large enough to collect sufficient light to see our hypothetical world.

To begin with, we calculate the surface area of an imaginary sphere, centred on the planet, with a radius equal to the distance between the telescope array and planet, given by the equation

where R is the distance from the planet to collector, specifically (10.47 light years). Next, taking the collection area from equation Telescope-collection-area, and the surface area of the imaginary sphere from equation Sphere-10.47-ly-radius, we can then find the fraction of the sphere’s area covered by the telescope array,

multiplying this fraction by the photons reflected by the planet, as given by equation Planet-reflected-light, we find

this is roughly 2 to 7 times the minimal photon flux detectable by the human eye Teich:82, considering that CCDs are generally more sensitive than the human eye, this is probably a sufficient photon flux to take useful images. Multiplying this by 60 gives us the photons per minute,

Alternatively, we can take the collection area of the James Webb Telescope, that is, 25.4 square metres JWST:2020, and dividing it by area of the imaginary sphere from equation Sphere-10.47-ly-radius, we get a new fraction, which we then multiply by the photons reflected by the hypothetical planet, from equation ([eq:Planet-reflected-light]), giving us the photons per second with a collection area equivalent to the James Webb Telescope,

so roughly 9 photons will be collected per second, multiplying this by 60, we find the photons collected per minute,

probably still sufficient to take useful images. From this, we can find the number of 30 mm diameter telescopes required to achieve a James Webb equivalent collection area, taking the area of each telescope as given by equation Telescope-collection-area, so

Therefore, we can conclude with only some 40,000 telescope units, each 30 mm in size, the telescope array can already achieve a collection area equal to that of the James Webb Telescope, albeit with a much higher resolution due to possessing a 100 kilometre baseline.

It must be noted that this simplistic formula ignores the curvature of the planet, which reduces the number of photons reflected directly back to the source. The formula also assumes that we can see the entirety of the illuminated surface of the planet, when in reality we will see only a partially illuminated disk.

And lastly, the formula approximates the number of emitted photons by dividing the total luminosity in joules per second by the energy in joules of a single photon of blue-green light, specifically a photon with a 500 nm wavelength, when in reality a wide spread of photons of all wavelengths are emitted. Nevertheless, these formulae provide a good first approximation, in order to roughly determine the collection area needed to provide a visible image.

Laser optics

It is important that we determine the size of the lenses needed to focus outgoing near-infrared laser beams across space to the individual telescopes, and incoming starlight to a waiting CCD. We can use this information to, at a later date, make a comprehensive estimate on the cost of manufacturing and launching the Collector-Laser, which will by far be the most massive, and one of the largest, components of the Planet Seeker Interferometer.

The actual utmost largest single component, though quite low in mass, will be the reflector, consisting simply of an unfolding circular sheet of lightweight aluminium or gold foil, needed to reflect laser beams to the opposite side of the individual telescopes, in order to hold them in position.

We are relying on lasers to hold the individual telescopes in place against the forces of Earth's gravitational attraction, and light pressure from the Sun, in order to get an idea how large a laser focusing lens is required, to achieve a spot size small enough to produce the needed counteracting force, and therefore how large the housing of the Collector-Laser must be, we must first find the laser spot size RT, given by the following equation, derived from one of the equations found on Chung's Atomic Rockets website Chung:Energywep,

where D is the distance between the Collector-Laser and the individual telescopes, which we have assumed to be 1000 kilometres, far enough away to easily illuminate the entire array, where λ is the wavelength of the laser light, assumed to be 1000 nm , and where RL is the radius of the laser focusing lens, in metres. As we can see, to achieve a spot size close to the diameter of the individual telescopes, the focusing lenses must be 6 metres across!

A million focusing lenses, each 6 metres across is hardly practical, or is it?

We have already talked of using tissue paper-thin plastic lenses for focusing incoming starlight to the Collector-Laser, why not apply this technique to the laser focusing lenses as well? Rather than a million individual lenses, we can simplify matters by using a single circular piece of plastic film, several kilometres across, and etched with a million Fresnel zone plates, held in place against Earth’s gravity by the pressure of the laser beam, which will illuminate the sheet more-or-less equally, as we have mentioned and shown.

If the sheet deviates to the side of the laser beam in any direction, then as with the free-flying telescope lenses, a correcting force will appear and act on the sheet, moving it back into alignment. To stop the laser light pressure from pushing the sheet away, we can etch and layer up the plastic in very precise diffraction patterns to cause a portion of the laser beam (most of which will miss the focusing lenses anyway) to be refocused a short distance away, producing a counteracting light pressure opposite the Collector-Laser, appearing only once a specific distance is reached, elsewise we can make use of the Reflector to hold the sheet in position, see the figures above or the interative model below to get an idea of how the sheet can be held in place via laser light.

Now to find if the laser spot size given by equation Laser-spot-size provides sufficient brightness, firstly, we will assume a frequency doubling efficiency De from near-infrared to blue-green light of 50%, a low estimate, as efficiencies of 85% have been reported Ou:92, we will also assume that the desired photon count at the collecting CCD, Nγ, to be 10,000 photons per second. Given these assumptions, the laser energy at emitter BP is given by the following equation, also derived from an equation found on Chung's Atomic Rockets Chung:Energywep,

where BPT is the energy density of the laser spot, given in Joules per square metre, and T is the radius, in metres, of the beam spot at the target, from equation Laser-spot-size, and where Bγ is the energy of single near-infrared photon in Joules, specifically giving an energy of , an utterly minuscule amount of energy.

Indeed, according to Labeyrie, 3 milliwatts of laser power are required per telescope lens in order to keep them in place HypertelescopeOrg:202010.1117/12.460844, this far exceeds—by an absurdly wide margin—the calculated laser brightness needed to amplify collected starlight, as given by equation Laser-energy. Given this, we could make do with a much larger spot size and correspondingly smaller laser focusing lens, however, if the spot size is too large then the gradient from centre to edge of the laser ‘spot’ may be too gradual for the individual telescopes to self-centre on the beam.

For the sake of this paper, we have made an educated guess, assuming that a 6 metre laser focusing lenses, producing a spot size of approximately 50 millimetres, is probably a good balance. Refining this estimate will require further investigation, however, as shown by Ognjen Ilic & Harry Atwater, in the case of laser-driven interstellar probes, a high ratio of beam width to beamrider diameter, where the beam width is much greater than the beamrider’s diameter, is preferable and more stable than a lower ratio ognjen-atwater:2019, similar conclusions apply to the free-flying telescope lenses.

Ground-based prototype

The usefulness of a ground-based prototype depends on its resolution, while it would be useful–and necessary–to build a prototype of the Planet Seeker on the ground, regardless of its resolution, if the resolution is great enough then the prototype becomes useful in its own right as an astronomical tool, perhaps even able to image nearby exoplanets directly, see above for a simplified diagram of how the ground-based prototype may be constructed.

To ascertain the resolution, and therefore usefulness, of a ground-based prototype, we start once again with equation Telescope-resolution, with the same wavelength, but this time with a baseline of only 1 kilometre , giving us the following result:

Next we take the result of equation Circle-10.47-ly-radius and the angle given by 1-km-baseline-resolution and input it into equation Smallest-resolvable-feature-100-km-baseline,

Where Rm is the size, in metres, of the smallest resolvable feature, which we can see is about 60,000 kilometres, too low a resolution to image a hypothetical terrestrial planet at Ran directly, but more than adequate to resolve giant planets. This would, for example, enable confirmation of (or conclusively rule out) the proposed gas giant AEgir, or the other giant planets that have been hypothesised to explain the gaps in Ran's debris belts.

Suppose it will be practical to build a larger ground-based array, or perhaps a small space-based array, with a baseline of, let us say 5 kilometres, in which case

then the size of the smallest resolvable feature is around 95% of Earth's equatorial diameter lide2000handbook, plenty to start with!

From this we can conclude that it would be a useful and worthy effort to build a ground-based prototype, immediately able to directly image nearby giant exoplanets, and possibly terrestrial planets as well, if the prototype is sufficiently large.

Construction and Cost

It is almost too early to give even rough estimates of the costs involved in this project, however, a very broad overview can be managed.

A rough cost analysis

At this stage it appears the two most expensive aspects of the project will be launch costs, as well as the costs involved in the research and development of the Collector-Laser.

Based on figures given on the SpaceX website, we conclude that the entire interferometer will cost at least $62 million USD SpaceX:2020 to be launched, though probably closer to $70 million USD. The individual telescopes themselves can be launched for less than $3 million USD by making use of SpaceX’s rideshare program for small satellites SpaceXRideshare:2020, as the million lenses are only 30 millimetres across and microns thick, easily fitting within a rather small volume.

Construction of the Planet Seeker Interferometer

The individual telescopes of the Planet Seeker are little more than etched pieces of micron-thick plastic, and using the new technique discussed earlier, the 1 million lenses required for the full array could be mass-produced at a very low cost-per-lens doi:10.1021/acsnano.5b03165, perhaps as little as $0.1 USD or equivalent, though this is only an educated guess. Research, and especially development, is required before a firm estimate on the cost of lens manufacture can be given, as the technology must be scaled up from a lab prototype first, or at the very least, this process must be started in order to begin to make an estimate on the cost.

The primary costs involved in the manufacture of the lenses appears to be the initial cost of the laser equipment and clean room, followed by the cost of vacuum-grade plastic with the correct composition and optical properties, and lastly labour and electricity costs.

The Collector-Laser will be more involved to develop and construct, with the bulk of the cost and effort going into the precise arrangement of the laser splitter or splitters, and in maintaining a clean room environment, that said, such expertise and facilities are already in existence.

One of the primary purposes of this paper, and especially the International Research Institute for Space, is to bring awareness to, and draw the interest of, needed specialists.

Call to Action

This is a call to action, a foundation to get the ball rolling, to get things started. We have the technological prerequisites to design, develop, build, and launch a telescope capable of finding another Earth, another habitable world.

In a year’s time, we could have an organization developing a prototype of the telescope, and in five… We could together be watching its launch, knowing that the Age of Interstellar Discovery is dawning.

To begin with we need to create a flyable design, all the bells and whistles, an absolutely complete and airtight final design. Following this, we will begin research and development of the hardware, and software, needed for the Planet Seeker Interferometer, testing and refining the technology by way of a ground-based prototype.

Ultimately, this is perhaps the grandest and most important project humanity has ever undertaken, we cannot remain on Earth alone forever, nor even within our solar system, sooner or later the Sun will die, and our very distant descendants will die with it, unless we take the actions necessary now, to ensure that we become a star-faring species.

The Planet Seeker is only the beginning of a grand adventure, an adventure of epic proportions, to explore and colonise distant worlds orbiting alien suns. If we take this step, if a brave few of us dare to go against the current, ignore cries of economic irrelevance and the ‘impossibility’ of the task at hand, then our distant descendants will look back on this moment, from their homes amongst the stars, and wonder at the courage and vision of those mighty pioneers.


R.L. Forward. Rocheworld. Baen Books science fiction. Baen Books, 1990.

Qiancheng Zhao, Ali K. Yetisen, Aydin Sabouri, Seok Hyun Yun, and Haider Butt. Printable Nanophotonic Devices via Holographic Laser Ablation. ACS Nano 9(9):9062-9069, 2015. PMID: 26301907.

Association Hypertelescope LISE, Hypertelescope, 2020 (accessed April 29, 2020).

D M Raup and J J Sepkoski. Periodicity of extinctions in the geologic past. Proceedings of the National Academy of Sciences, 81(3):801—805, 1984.

Adrian L. Melott and Richard K. Bambach. Nemesis reconsidered. Monthly Notices of the Royal Astronomical Society: Letters, 407(1):L99—L102, 09 2010.

Michael R. Rampino, Ken Caldeira, and Yuhong Zhu. A pulse of the earth: A 27.5-myr underlying cycle in coordinated geological events over the last 260Â myr. Geoscience Frontiers, 12(6):101245, 2021.


Matthew J. Holman and Matthew J. Payne. Observational constraints on planet nine: Astrometry of pluto and other trans-neptunian objects. The Astronomical Journal, 152(4):80, Sep 2016.

A. Brunini and M.D. Melita. The existence of a planet beyond 50 au and the orbital distribution of the classical edgeworth-kuiper-belt objects. Icarus, 160(1):32—43, 2002.

Ian Sample. Dwarf planet discovery hints at a hidden Super Earth in solar system, 2014 (last modified on March 26, 2014, accessed June 26, 2021).

Konstantin Batygin, Fred C. Adams, Michael E. Brown, and Juliette C. Becker. The planet nine hypothesis. Physics Reports, 805:1—53, 2019. The planet nine hypothesis.

Konstantin Batygin and Michael E. Brown. Evidence for a distant giant planet in the solar system. The Astronomical Journal, 151(2):22, Jan 2016.

Michael E. Brown and Konstantin Batygin. Observational constraints on the orbit and location of planet nine in the outer solar system. The Astrophysical Journal, 824(2):L23, Jun 2016.

L. Koechlin, D. Serre, and P. Deba. The Fresnel interferometric imager. apss, 320(1):225–230, April 2009.

Koechlin, L., Serre, D., and Duchon, P. High resolution imaging with fresnel interferometric arrays: suitability for exoplanet detection. A&A, 443(2):709–720, 2005.

Antoine Labeyrie, Herve Le Coroller, Julien Dejonghe, Frantz Martinache, Virginie Borkowski, Olivier Lardiere, and Laurent Koechlin. Hypertelescope imaging: from exoplanets to neutron stars. In Michael Shao, editor, Interferometry in Space, volume 4852, pages 236 – 247. International Society for Optics and Photonics, SPIE, 2003.

Ognjen Ilic and Harry Atwater. Self-stabilizing photonic levitation and propulsion of nanostructured macroscopic objects. Nature Photonics, 13, 04 2019.

Ying-Ju Chu, Nelson Tabiryan, and Grover Swartzlander. Experimental verification of a bigrating beam rider. Physical review letters, 123:244302, 12 2019.

Rocco Gaudenzi, Davide Stefani, and Santiago Jose Cartamil-Bueno. Light-induced propulsion of graphene-on-grid sails in microgravity. Acta Astronautica, 174:204 – 210, 2020.

Industrial Laser Solutions. 3 kW fiber laser, December 10, 2012 (accessed May 28, 2020).

Farzana I. Khatri, Bryan S. Robinson, Marilyn D. Semprucci, and Don M. Boroson. Lunar laser communication demonstration operations architecture,. Acta Astronautica, 111:77 – 83, 2015.

Z. Y. Ou, S. F. Pereira, E. S. Polzik, and H. J. Kimble. 85% efficiency for cw frequency doubling from 1.08 to 0.54 µm. Opt. Lett., 17(9):640–642, May 1992.

G. W. Webb, I. V. Minin, and O. V. Minin. Variable Reference Phase in Diffractive Antennas: Review, Applications, New Results. IEEE Antennas and Propagation Magazine, 53(2):77–94, April 2011.

Charles R Greathouse IV. OEIS: A245461, July 22, 2014 (last modified on May 28, 2020, accessed May 28, 2020).

Ignasi Ribas. The sun and stars as the primary energy input in planetary atmospheres. Proceedings of the International Astronomical Union, 5, 11 2009.

D.R. Lide. Handbook of Chemistry and Physics: A Ready-Reference Book Chemical and Physical Data. CRC-Press, 2000.

International Astronomical Union. RESOLUTION B2 on the re-definition of the astronomical unit of length, 2012.

David R. Williams. Earth Fact Sheet, April 2, 2020 (accessed May 28, 2020).

Malvin Carl Teich, Paul R. Prucnal, Giovanni Vannucci, Michael E. Breton, and William J. McGill. Multiplication noise in the human visual system at threshold: 1. quantum fluctuations and minimum detectable energy. J. Opt. Soc. Am., 72(4):419–431, Apr 1982.

Space Telescope Science Institute. JWST Telescope, May 13, 2017 (last modified December 23, 2019, accessed May 28, 2020).

Winchell Chung. Energy Weapon Sidearms: Spot Size and Brightness, 1995-2020 (last modified on May 11, 2020, accessed May 30, 2020).

SpaceX. Capabilities & Services, 2020 (accessed May 28, 2020).

SpaceX. Smallsat Rideshare Program, 2020 (accessed May 28, 2020).