Searches for Robotic Probes in the Solar System Eamonn Ansbro - - PowerPoint PPT Presentation
Searches for Robotic Probes in the Solar System Eamonn Ansbro Kingsland Observatory RAS NAM: SETI Sessions St Andrews, July 5 2013 SETI, OSETI, SETA SETI, OSETI, SETA SETA: Search for Extraterrestrial Artefacts SETA: Search for
Eamonn Ansbro
Kingsland Observatory
RAS NAM: SETI Sessions St Andrews, July 5 2013
SETA: Search for Extraterrestrial Artefacts
Hypothesis states:
Technological advanced extraterrestrial
From what we’ve learnt as experienced on Earth in science, it seems that both an Extraterrestrial Civilizations arise from a long process of apparently incidental interaction of astrophysical, physical and chemical factors ?
Our own galaxy may have around 10, 000 civilizations
Some civilizations will be unified with a universal vision, flourishing, exploring
Some civilizations may have destroyed themselves
A civilization will explore its local solar system and harness its energy
An intelligent civilization may be at a stage, has developed technology and wants to explore for others.
If they exist, why don If they exist, why don’ ’t we t we see them? see them?
Message left by terrestrial interplanetary probes in the solar system Pioneer Voyager If there are ET probes in the Solar System its possible we would be able to find them
ET Civilization 2000 years
Option: Option: “ “timid home bodies timid home bodies” ” Technical civilization that stays at home, but they communicate. Explores the solar Technical civilization that stays at home, but they communicate. Explores the solar system with robotic probes system with robotic probes
ET Civilization 3000 years
Option 2: Option 2: “ “Backyard conquerers Backyard conquerers” ” Technical civilization travel but only conquer there own solar system and limit Technical civilization travel but only conquer there own solar system and limit themselves to communications with other stellar systems. themselves to communications with other stellar systems.
Età Civiltà 4.000 Anni Età Civiltà 4.000 Anni
Option 3: Slow travellers Option 3: Slow travellers Technical civilization travels, conquering there own Technical civilization travels, conquering there own solar system and also several nearby stellar systems solar system and also several nearby stellar systems using mobile Dyson Spheres using mobile Dyson Spheres
ET Civilization 10,000 years old Predater ……. Predater ……. …… ……. Or Altruistic? . Or Altruistic?
Well travelled cosmos
Option 4: Fast travellers Option 4: Fast travellers Technical civilization become Technical civilization become completely nomadic completely nomadic
ET Civilization 1,000,000 years old
Option 5: Option 5: “ “transuniversalists transuniversalists” ” Technical civilization jump from Technical civilization jump from Universe to another Universe to another
Search for ET Probes If they have reached our Solar System, Where have they come from? From other planets in this Galaxy / or another galaxy
From other dimensions
How do they do it?
The Artefact Hypothesis states that a technologically advanced The Artefact Hypothesis states that a technologically advanced extraterrestrial civilisation has undertaken a long-term extraterrestrial civilisation has undertaken a long-term programme of galactic exploration via transmission of material programme of galactic exploration via transmission of material
artefacts are potentially available to test this Hypothesis: artefacts are potentially available to test this Hypothesis:
Astro engineering activities, Astro engineering activities,
self-replicating artefacts, self-replicating artefacts,
passive artefacts, passive artefacts,
active probes. active probes. Of these, only Of these, only active self-repairing probes active self-repairing probes are likely both to exist are likely both to exist and to be observable from within the Solar System. and to be observable from within the Solar System.
Freitas and Valdes (L points)30( inch Tel. <16 mag.) Papagiannis (Asteroid Belt) using IRAS data
From an observational standpoint all extraterrestrial artefacts fall into one of From an observational standpoint all extraterrestrial artefacts fall into one of three classes: three classes:
Class I objects Class I objects intended to be found, intended to be found,
Class II objects Class II objects intended not to be found, intended not to be found,
Class III objects Class III objects for which detection by us is irrelevant or unimportant. for which detection by us is irrelevant or unimportant.
The simplest assumption is that extraterrestrial technology is sufficient to The simplest assumption is that extraterrestrial technology is sufficient to guarantee the intended result. guarantee the intended result.
Class I objects Class I objects cannot be present in the Solar System because we have not cannot be present in the Solar System because we have not
Class II objects Class II objects may be present but it is impossible for us to observe them. may be present but it is impossible for us to observe them.
Class III objects Class III objects may be observable. may be observable. The exploration goal restricts the search The exploration goal restricts the search space for observable space for observable Class III artifacts Class III artifacts. These objects must elect to reside in the . These objects must elect to reside in the best possible location from which to monitor phenomena relevant to their best possible location from which to monitor phenomena relevant to their
so the simplest assumption is that the probe will recognize the fact and take up so the simplest assumption is that the probe will recognize the fact and take up residence nearby, stationing itself in residence nearby, stationing itself in lunar or cislunar orbit. lunar or cislunar orbit.
I
I nstrument visual/photometric artifact searches of Earth-Moon lib nstrument visual/photometric artifact searches of Earth-Moon lib to mag. +22 mag. to mag. +22 mag.
Infrared search for "warm" artefacts (T ³ 50oK) in Earth-
Infrared search for "warm" artefacts (T ³ 50oK) in Earth- Moon libration and solar polar orbits Moon libration and solar polar orbits
Instrument artefact search of Earth-Moon libration and
Instrument artefact search of Earth-Moon libration and solar polar orbits to mag. +24 solar polar orbits to mag. +24
Instrument ecliptic survey to mag. +20/+24, looking for
Instrument ecliptic survey to mag. +20/+24, looking for evidence of incoming fusion braking rockets, solar sails, evidence of incoming fusion braking rockets, solar sails, interstellar ramjet plumes, laser push beam backlighting, or interstellar ramjet plumes, laser push beam backlighting, or relic corner reflectors relic corner reflectors
An appropriate observational search limit for an ET messenger probe size is 1-10 m An appropriate observational search limit for an ET messenger probe size is 1-10 m
The continuous visible sky search limit has been to 20 mag by Linear and Spacewatch. The continuous visible sky search limit has been to 20 mag by Linear and Spacewatch. Unfortunately, PanStarrs is not a dedicated instrument for continuous sky coverage down Unfortunately, PanStarrs is not a dedicated instrument for continuous sky coverage down to +22 mag for the best ground-based telescopes. to +22 mag for the best ground-based telescopes.
Current surveys could not have detected even a 1- to 10-m probe more than 0.01-1 AU Current surveys could not have detected even a 1- to 10-m probe more than 0.01-1 AU from Earth, so heliocentric orbital space is at least 99.999% unexplored for 1- to 10-m from Earth, so heliocentric orbital space is at least 99.999% unexplored for 1- to 10-m
Pioneer 10 with a low albedo Pioneer 10 with a low albedo
An important aspect of a probe-SETI search programme is the feasibility of detecting an An important aspect of a probe-SETI search programme is the feasibility of detecting an artefact using existing instrumentation. The most conservative assumption is that the artefact using existing instrumentation. The most conservative assumption is that the artefact has a uniform distribution over the search space. artefact has a uniform distribution over the search space.
A wide-field telescope with characteristics similar to a proposed telescope array but with A wide-field telescope with characteristics similar to a proposed telescope array but with V V +24 could search each orbital region except geocentric to ~1 m, and geocentric to ~10 m, +24 could search each orbital region except geocentric to ~1 m, and geocentric to ~10 m, for 2 years. for 2 years.
Kingsland
Experimental dual
Visible and SWIR
nd magnitude
Wynne Newtonian
Ground based One Metre Telescope
Visible to (SWIR) Short Wave IR
Simultaneous monitoring in two
SWIR: (1 to 2.5 microns)
Prime focus, f/2.4 Prime focus, f/2.4
Spatial sampling 0.76 arcsec/pixel Spatial sampling 0.76 arcsec/pixel
Field of View 5 Sq.degrees, 2.23 x Field of View 5 Sq.degrees, 2.23 x 2.23 degrees 2.23 degrees
Sky coverage 5000 sq.degrees in an
Sky coverage 5000 sq.degrees in an 8 hour period with a s/n=5, to 8 hour period with a s/n=5, to magnitude 22 (r magnitude 22 (r’) with 1.25 seeing ’) with 1.25 seeing mean FWHM mean FWHM
Short download times 2 seconds Short download times 2 seconds
Increases the FOV
Increases the FOV
Integration: improves
Integration: improves the LM to 24 mag. the LM to 24 mag.
Similar to SuperWasp
Similar to SuperWasp
Specification 100 unit 1-m 112Mp 100 unit 1-m 250Mp 100 unit 2-m 250Mp Unit FOV (degrees2) (seamless) 5 5 2 Unit image size (pixels) 10,580 x 10,560 15,500x 15,500 15,500 x 15,500 Maximum array FOV (degrees2) 500 500 200 Array image size in max FOV 105,800 x 105, 800 155,000 x 155,00 155,000 x 155,00 Equivalent collecting area (m2) 67 67 300 Equivalent aperture (m) 8.5 8.5 20 Array tendue (m2deg2) 340 340 600 PSF (/pixel) 0.76 0.51 0.33
Parameter Parameter Array Array Large Single Large Single Configuration Flexibility Configuration Flexibility Infinite (Large FOV or large Aperture) Infinite (Large FOV or large Aperture) Very limited Very limited Instrumentation Instrumentation Imaging only Imaging only Very flexible Very flexible Resiliency Resiliency Very large Very large NONE NONE Multi-Spectral (ugriz) Multi-Spectral (ugriz) Real Time Real Time Time delayed Time delayed Instant Parallax Instant Parallax Yes up the 1000 a.u. Yes up the 1000 a.u. NO NO
Dynamic Dynamic
Range
Range
Very Large, multiplies by #units Very Large, multiplies by #units Wells fill up quickly, limited Wells fill up quickly, limited Number of users (projects) Number of users (projects) Single or Limited by # units in array Single or Limited by # units in array Single Single Downtime Downtime 100% always available 100% always available YES YES Cosmic ray removal Cosmic ray removal Very easy Very easy Tedious Tedious Revenue generation Revenue generation Significant (~5X than single) Significant (~5X than single) Limited and fixed Limited and fixed Real time correlation Real time correlation analysis analysis Yes Yes NO NO Expandability Expandability Yes (cost efficient) Yes (cost efficient) Very difficult (very expensive) Very difficult (very expensive) Large FOV Large FOV Yes Yes extremely efficient (very large) extremely efficient (very large) Very difficult and expensive Very difficult and expensive Time to bring on line Time to bring on line ~3 years first element, successive ~3 years first element, successive elements added every few weeks elements added every few weeks Up to a decade or more Up to a decade or more Operational cost Operational cost Higher than single telescope due the Higher than single telescope due the large number of elements to large number of elements to maintain maintain Industry average Industry average Spectral Range Spectral Range ugriz ugriz Broadband Broadband Spectroscopy Spectroscopy Every object in the field through Every object in the field through distributed narrowband filters distributed narrowband filters Selected objects through optical fibers, Selected objects through optical fibers, gratings etc gratings etc
The following "magic orbits" are the targets for a preliminary SETA
The following "magic orbits" are the targets for a preliminary SETA programme. programme.
The potential search volume thus reduces to five distinct orbital
The potential search volume thus reduces to five distinct orbital classes (all of which are poorly studied for 1-10 m objects): classes (all of which are poorly studied for 1-10 m objects):
Geocentric orbits between two Earth-centred concentric spheres of
Geocentric orbits between two Earth-centred concentric spheres of radii 70,000 and 326,400 km radii 70,000 and 326,400 km
Selenocentric orbits between 3000 and 58, 100 km lunar altitude,
Selenocentric orbits between 3000 and 58, 100 km lunar altitude,
stable synodic libration orbits around Earth-Moon Lagrangian
stable synodic libration orbits around Earth-Moon Lagrangian points L4 and L5 points L4 and L5
Earth-Moon halo orbits near collinear Lagrangian points L1 and L2
Earth-Moon halo orbits near collinear Lagrangian points L1 and L2
Sun-Earth L4/L5 Lagrangian orbits.
Sun-Earth L4/L5 Lagrangian orbits.
Four classes of artefacts are defined: Four classes of artefacts are defined:
Those seeking contact, Those seeking contact,
Those seeking to avoid contact, Those seeking to avoid contact,
Those intended to provide a passive technological threshold for Those intended to provide a passive technological threshold for detection, detection,
Those for which detection is irrelevant. Those for which detection is irrelevant.
The Search for Extraterrestrial Artifacts (SETA) is based on the The Search for Extraterrestrial Artifacts (SETA) is based on the latter two classes. Under the assumption that an extraterrestrial latter two classes. Under the assumption that an extraterrestrial probe will be interested in life in our solar system, a near-Earth probe will be interested in life in our solar system, a near-Earth search space is defined. This search space is accessible to us now search space is defined. This search space is accessible to us now with ground and even satellite observing facilities. with ground and even satellite observing facilities.
probes to our solar system is possible, not constrained by the probes to our solar system is possible, not constrained by the speed of light. This widens the constraints of the Drake speed of light. This widens the constraints of the Drake Equation. Equation.
astrophysical approach for detection for 1m – 10m probes. astrophysical approach for detection for 1m – 10m probes.
4.Existing instrumentation is adequate for Earth Moon system 4.Existing instrumentation is adequate for Earth Moon system targeted surveys targeted surveys
field of view to 24 mag to detect 1m to 10m probes within the field of view to 24 mag to detect 1m to 10m probes within the ecliptic and beyond ecliptic and beyond
within the Solar System within the Solar System