Elora is a name meaning ‘The laurel of victory’. Within this paper, The Ethical Skeptic has proposed for consideration a concept for an elegant, flexible, high delivery-mass, rapid response, high kinetic-energy and low rubble-fragmentation system called ELORA. A Lagrange exploiting orbital array around the Moon, which can be rapidly deployed to interdict an approaching Earth-impactor threat, through massive, adaptable and repeated kinetic impact. It is the contention of this white paper that this concept system offers features superior in every facet of challenge, to the existing asteroid/comet deflection technologies under consideration.
Elora is a name bearing the meaning ‘the laurel of victory’. The symbol of the laurel wreath traces back to Greek mythology. Apollo, god of warfare archers and archery, was often represented wearing a laurel wreath which encircled his head, as a crown of symbolic power. Accordingly, in the Greek Olympics such laurel wreaths were crafted from a wild form of olive tree known as “kotinos” (κότινος). In the later Roman context, laurel wreaths were symbols of martial victory, crowning a successful commander for having just vanquished an enemy force with rapidity.1
Rapid is a business term, which is used to encompass both the contexts of quickness in response (Amazon) and fastness in delivery (FedEx). ELORA, is a gravity-exploiting wreath, worn around the head of the Moon, designed to mitigate large celestial future and importantly, emergent Earth-impacting orbital bodies, through a rapid, repeatable, and overwhelming kinetic response. A system which solves (in the concept presented herein) many of the problems which face today’s proposed Earth-impactor mitigation ideas, and yet bears few of their disadvantages.
ELORA is an acronym for: Earth-Lunar Lagrange 1 (ELL-1) Orbital Rapid Response Array. ELORA is a proposed system to interdict and deflect Potential Hazardous Objects to Earth. It is a series of Lunar dust bags that each perform kinetically like shotgun pellets. They are bagged on the Moon and then individually launched to Earth-Lunar Lagrange point 1, in order to be assembled into massive single payloads of bound-but-separate dust bags – yielding a total of 1000 – 3000 kilotons of TNT (about 2.8 – 4.2 Petajoules) of direct kinetic energy per payload. Twelve of these 1728-bag/200,000 kilogram single payloads are to be assembled, which will station as Trojan ELL-1 payloads; ready to be rapid deployed to any Lunar orbit inclination in order to interdict large (>50 meters) and short notice Near Earth or Potential Hazardous Objects (NEO/PHO) from space. The array as a concept is easy to assemble and offers redundancy, power, and rapidity unparalleled by existing conceptual alternative interdiction approaches.
Of top concern among those scientists tasked to forward-think about threats to mankind, is the real possibility that the Earth will be someday threatened by a rogue asteroid, comet or other, even extra-solar space debris – which becomes a Potential Hazardous Object (PHO).2 3 Current plans to address cosmic impactor threats include nuclear warheads and various ingenious forms of imbuing physical effects to the PHO object or add or subtract momentum from its solar-orbital vector.
‘This one did sneak up on us’: Internal emails reveal how NASA almost missed Asteroid ‘2019 OK’ (a 130 meter asteroid) when it whizzed past Earth in July, within 24 hours of its detection.4
In 2011, the director of the Asteroid Deflection Research Center at Iowa State University, Professor Bong Wie began to study strategies that could deal with 50-to-500-metre-diameter (200–1,600 ft) objects when the time to Earth impact was less than one year. He concluded that to provide the required energy, a nuclear explosion or other event that could deliver the same power, are the only methods that can work against a very large asteroid within these time constraints.5 It is the contention of this author, that space deployed nuclear warheads constitute a dangerous, expensive, and less effective means of mitigating such objects. A massive high-kinetic shotgun payload system such as ELORA will deliver more kinetic energy, more rapidly, and in more overwhelming fashion, than can nuclear warheads – bearing less of the downsides and costs of nuclear or other approaches.
Existing Approaches to Asteroid Deflection/Mitigation
Various PHO and emergent bolide collision avoidance techniques have different trade-offs with respect to metrics such as overall performance, cost, failure risks, redundancy, operations, and deployment readiness. There are various methods under serious consideration now, as means of changing the course of any potential Earth threat. These can be differentiated by various attributes such as the type of mitigation (deflection or fragmentation), energy source (kinetic, electromagnetic, gravitational, solar/thermal, or nuclear), and approach strategy (long term influence or immediate impact).6
Potential Hazardous Object (PHO) Problem Definition: Four Challenges Exist
1. PHO interdiction technologies exist in a convex technology trade-off relationship of diminishing marginal returns (lower blue curve in the graphic below), in that,
a. What can be deployed quickly or be easily maneuvered in space, is also not sufficient to do the job.
b. What can do the job, cannot be deployed quickly nor be maneuvered easily in space.
2. Hydrogen (lithium deuteride or equivalent) core detonations are theoretically effective for low diameter bodies, yet diminish in effectiveness (upper blue curve in the graphic below) asymptotically to a maximum of a 100 – 150 meter bolide, as constituting the largest effective body which the technology can be employed to interdict.
3. Current estimates of effectiveness are theoretical only – a condition wherein neither their adequacy at the job, nor rapidness/maneuverability in deployment can be easily tested against mock threat conditions prior to their actual need.
4. No System to date has offered a low-cost, rapidly deployable, scalable, flexible, testable, centuries-durable, low maintenance, all aspect angle, low fragmentation, redundant, bolide-mass altering, high-mass/kinetic potential, and multiple-impactor solution – which can address the emergent or otherwise 150+ meter diameter body.
The various current approaches to deflecting a wayward celestial body fall into four approach categories (Note: These are all derived/reworded and modified/categorized into a more logical taxonomy, from Wikipedia: Asteroid Impact Avoidance):
Fragmentation – explosive or high velocity kinetic methods which seek to pulverize the orbital body into both bolides which take non-threatening orbital tracks (achieve orbital body escape velocity) or pose less of a destructive threat when they do eventually enter the Earth’s atmosphere (hopefully less than 35 meters in average diameter). These can be executed in either an emergent or long-term strategy.
1. Hypervelocity Asteroid Mitigation Mission for Emergency Response (HAMMER) – a spacecraft (8 tonnes) capable of detonating a nuclear bomb to deflect an asteroid through two methods of approach:
a. Nuclear Impact Device (NID) – a direct impact by a nuclear device causes the body to be broken through concussion into smaller pieces of both escape velocity and less-damaging characteristics.
b. Nuclear Standoff Device (NSD) – a nuclear device or series thereof, are detonated a given distance from the orbital body. The kinetic energy of thermal and fast neutrons, along with x-rays and gamma rays causes a push which changes the track of the orbital body (note, this is not the same as cometization).
2. Dual Warhead Nozzle-Ejecta – a two stage nuclear/nuclear approach, which combines an initial nuclear blast to create a provisional deep crater, which is then followed by a second subsurface nuclear detonation within that provisional crater (the nozzle), which would generate an ejecta effect and high degree of efficiency in the conversion of the x-ray and neutron energy that is released into propulsive energy to the orbital body.
Kinetic Energy/Impact – massive and high velocity man-assembled bodies which impact the orbital body directly and impart a resulting inertial/momentum transfer change to its orbit.
3. Asteroid Redirect – capture and employment of another asteroid body as an inertial mass which is directed to impact and fragment or alter the trajectory of the threatening orbital body.
Earth-Lunar Lagrange 1 Orbital Quick Response Array (ELORA) – a large kinetic object and quick response approach developed by The Ethical Skeptic. A series of Lunar dust bag bundles, bound together into large, massive projectiles held on station at Earth-Lunar Lagrange Point 1 and subsequently placed into any needed inclination Lagrange orbit around the Moon. These would be short notice directed by thruster and/or Moon-Earth slingshot towards the approaching orbital body, exploiting the low/zero gravity of Earth-Moon Lagrange 1, and targeted for a direct high velocity/high kinetic impact. The bags can be un-bound at the last minute, in order to form a larger impact pattern (shotgun effect) in the case of a rubble pile asteroid, thereby distributing the momentum over a larger area of the orbiting body and displacing a greater amount of the rubble and reducing fragmentation.
4. Hypervelocity Asteroid Intercept Vehicle (HAIV) – a two stage kinetic/nuclear hybrid approach, which combines a kinetic impactor to create an initial crater, which is then followed by a subsurface nuclear detonation within that initial crater, which would generate a lensing effect and high degree of efficiency in the conversion of the x-ray and neutron energy that is released into propulsive energy to the orbital body.
5. Conventional Rocket Engine – launching and attaching any spacecraft propulsion engine to the center of mass of the orbital object, and using the engine to give a push, possibly forcing the asteroid onto a non-threatening trajectory.
Gradualization – various approaches by means of technology, engines, colors, lasers or offset thrust devices which serve to push, pull, alter the solar pressure on or cometize the orbital body.
6. Gravity Tractor Thrust Rockets – a more massive thruster spacecraft is placed into orbit around the Earth-threatening orbital body. A slow thrust is applied from the spacecraft’s engines, never exceeding escape velocity. The mutual gravitation between the two bodies begins to alter the trajectory of the orbital body from its original course.
7. Ion Beam Driver – involves the use of a low-divergence ion thruster mounted on an orbiting spacecraft, which is pointed at the center of mass of the asteroid. The momentum imparted by the ions reaching the asteroid surface produces a slow-but-continuous force that can deflect the asteroid in similar fashion to a gravity tractor, but with a much lighter spacecraft.
8. Solar Sail Push/Pull – attaching a solar sail either behind or on the surface of the orbital body, in order to use the solar wind to alter the trajectory of the orbital body.
9. Painting – altering the color of the orbital body to the opposite end of the color band from which it naturally exists. The whiter or blacker surface alteration would then provide for a differential dynamic in the absorption and reflection of solar photons and gradually alter the body’s trajectory over time via the Yarkovsky effect.
10. Solar Focusing – a technique using a set of refractory lenses or a large reflector lens (probably deployed foil) which focuses a relatively narrow beam of reflected sunlight onto a specific region of the orbital body, creating thrust from the resulting vaporization of material, solar wind or through amplifying the Yarkovsky effect, wherein photons emitted from the body itself serve to alter its trajectory.
11. Nuclear Pulse Propulsion – involves the use of a nuclear pulse engine mounted on a spacecraft, which lands on the surface of the asteroid. The momentum imparted by the nuclear pulses produces a slow-but-continuous force that can deflect the asteroid in similar fashion to a thruster rocket.
12. Cometization – heating the surface of the orbital body through a thermonuclear release of neutrons, x-rays, and gamma rays so that it begins to eject heated material from cracks or vents in the surface, in similar manner to a comet – thereby causing a thrust vector nudging of the orbital body itself for a short to moderate period of time. Depending on the brisance and yield of the nuclear device, the resulting ejecta exhaust and mass loss effects, would produce enough alteration in the object’s orbit to make it miss Earth.
13. Laser Ablation – focus sufficient laser energy from Earth or a space deployed laser or laser array, onto the surface of an asteroid to cause flash vaporization and mass ablation and create either an impulse or mass alteration which changes the momentum of the orbital body.
14. Magnetic Flux Compression – magnetically brakes objects that contain a high percentage of iron through deploying a wide coil of wire along the sides of its orbital path. When the body moves through the coil or tunnel, inductance creates an electromagnet solenoid effect which causes EM drag on the orbital body.
Mass Alteration – various methods of digging and ejecting or addition of added mass from/to the orbital body, thereby altering its long-term orbital track.
15. Deep Impact Collision – an impactor which injects itself deep into the surface of the orbital body, thereby changing both its velocity and net mass.
16. Mass Driver – a system landed onto the surface of an orbital body, which ejects material into space, thus giving the object a slow steady push as well as decreasing its mass.
17. Gravity Tractor Redirect – another smaller, but still significant spacecraft or redirected body is placed into orbit around the Earth-threatening orbital body. The added binary-systemic gravitation/mass of the new body alter the trajectory of the orbital body from its original course.
18. Tether Tractor – attaching a mass by means of a tether or netting, to the orbital body, thereby altering the net mass of the system and as well its orbital trajectory.
19. Dust/Steam Cloud Accretion – releasing dust or water vapor from a spacecraft or from a detonated redirected comet, which would subsequently be gathered/accreted by the orbital body and serve to alter its mass/trajectory over a long period of time.
20. Coherent Digger Array – multiple mobile or fixed flat tractors which attach to the surface of the orbital body and dig up material, ejecting it into space and thereby significantly altering the mass of the orbital body and changing its trajectory. The material could also be released from one side of the body as a coordinated fountain array with an added propulsive effect.
21. Net Drag – a durable net material which is deployed into the path of the orbital object, which then wraps around the object. This netting addition is added several times over until the net mass/momentum of the orbital body is changed.
Carl Sagan, in his book Pale Blue Dot, expressed concern about deflection technology, noting that any method capable of deflecting impactors away from Earth could also be abused to divert non-threatening bodies toward the planet.
If you can reliably deflect a threatening worldlet so it does not collide with the Earth, you can also reliably deflect a harmless worldlet so it does collide with the Earth. Suppose you had a full inventory, with orbits, of the estimated 300,000 near-Earth asteroids larger than 100 meters—each of them large enough, on impacting the Earth, to have serious consequences. Then, it turns out, you also have a list of huge numbers of inoffensive asteroids whose orbits could be altered with nuclear warheads so they quickly collide with the Earth…
Tracking asteroids and comets is prudent, it’s good science, and it doesn’t cost much. But, knowing our weaknesses, why would we even consider now developing the technology to deflect small worlds?…
If we’re too quick in developing the technology to move worlds around, we may destroy ourselves; if we’re too slow, we will surely destroy ourselves. The reliability of world political organizations and the confidence they inspire will have to make significant strides before they can be trusted to deal with a problem of this seriousness…
Since the danger of misusing deflection technology seems so much greater than the danger of an imminent impact, we can afford to wait, take precautions, rebuild political institutions—for decades certainly, probably centuries. If we play our cards right and are not unlucky, we can pace what we do up there by what progress we’re making down here…
The asteroid hazard forces our hand. Eventually, we must establish a formidable human presence throughout the inner Solar System. On an issue of this importance I do not think we will be content with purely robotic means of mitigation. To do so safely we must make changes in our political and international systems.
~[p 146-150], Pale Blue Dot, Carl Sagan
The critical path issue elucidated through this – is that a well designed and elegant deflection technology would be employed to increase the entropy of the interdiction circumstance, whereas using a redirect technology critically depends upon decreasing the entropy of that circumstance. In other words, by choosing a non-nuclear deflection (as opposed to redirection) we are pushing the threatening orbital body into any one of a billion potential outcomes, all of which are satisfactory in nature. In order to make a non-threatening orbital body suddenly become a threat, one must alter its trajectory to one specific outcome among billions. A task of extraordinarily greater difficulty – rendering that technology also not an optimal choice as an impactor-mitigating solution. I disagree with Sagan that all mitigation technologies will/can be used as an implement of warfare, and therefore must be delayed – as one need resign self to the single answer of nuclear detonations in order to assume that such a false dilemma exists.
Indeed, that dilemma does not necessarily exist. What we have proposed below, provides for a powerful, yet neutral, non-nuclear and single purpose system – which can only be employed to deflect incoming invaders with abandon, yet cannot be used to deflect them in order to purposely place Earth into harm’s way. The concept system resolves most every shortfall characteristic in the list of mitigation approaches above (see graph and list of technologies 1 – 21), and as well resolves Sagan’s concern, through use of simple technologies and focused on-task elegance in design.
Elegant Solution Approach: ELORA – Earth-Lunar Lagrange 1 Orbital Rapid Response Array
Below are presented five slides which serve to introduce the ELORA concept approach and feature set. The first, second and third slides serve to introduce the Lagrange exploitation construct, along with the principle involving 12 x 1728 bags of Lunar dust in Trojan Earth-Lunar Lagrange 1 station or targeting orbit around the Moon. The fourth slide speaks to the establishment of all-Lunar-inclination-angle target interdiction capability, while the fifth slide depicts the multiple impactor (up to 12) and shotgun (1728 ‘pellets’) approaches which achieve the enormous kinetic energy payload and low fragmentation outcome.
The development process consists of simply harvesting dust from the surface of the Moon, so that large particles are not created from spills in orbit around the Moon or after impact with the targeted bolide. This dust is bagged and launched into space in quantities of 12 bags. After 144 launches (much more cheaply executed from the surface of the Moon and its low gravity than from Earth), these 1728 bags of Lunar dust are bound together as a single 200,000 kg ‘payload’ – one single impactor designed to mitigate an Earth endangering NEO/PHO. Each payload is then affixed with a rocket and attitude control system, and then parked at Lagrange 1 (or ready-placed into Lagrange elliptical orbit around the Moon, in a variety of orbit inclinations so as to maximize celestial omnidirectional coverage). The payload is preset with small deployment charges which allow the bags of dust to be burst apart slightly, and to separate during the last 5 minutes of terminal approach, so that they act as a kind of shotgun effect on the targeted bolide.
The reasons why bags of Lunar dust must be employed are twofold:
First, stopping a larger mass to allow Trojan capture at Lagrange 1 is problematic in terms of the fuel required, and
Second, a shotgun-blast styled impactor will produce less bolide fragmentation per push-energy, than any other approach.
This is all accomplished at a space workstation called ELL-1 Payload Assembly, in Trojan orbit at Earth-Lunar Lagrange point 1. The Earth-Lunar Lagrange 1 Payload Assembly station would be used to conduct monitoring, maintenance, and upgrades of the system from then on. This would be absolutely essential due to the structure fatiguing and propellant degradation which each payload and its control system would experience, due to age or the constant repetitive changes in the Moon’s tidal gravity over each orbit. Alternatively, all 12 payloads may be kept on station as ready-station Trojan bodies at ELL-1. The Moon orbital phase for payloads under this approach would only be initiated when the actual deployment of the system was needed. This would delay the rapidness of response only by a couple of days. Of course, a hybrid system thereof may also be deployed, with a portion of the payloads in orbit and the remainder in Trojan station-keeping reserve so as to minimize maintenance demand.
The result is a single payload impactor (200,000 kg) with the force of 1000 – 3000 kilotons of TNT (about 2.8 – 4.2 Petajoules); in the range of 60 to 90 times as much energy as that released from the atomic bomb detonated at Hiroshima.
However, unlike a nuclear fusion core detonation (used by the most effective alternative approaches in the chart above) – ALL of an ELORA payload’s kinetic potential is transferred into momentum imparted to the orbital body.
Alternative approaches above would require 672 static load launches or 50 to 85 – B83 hydrogen nuclear core detonations in order to achieve the same inertial effect as 12 single payloads from an ELORA intervention – all static assets needing to be maintained by an international body for centuries, and then without warning be required within a matter of days.
And of course, ELORA could be tested on 150+ meter asteroids and NEOs, at low cost, whereas the Delta IV static load and B83 hydrogen warhead detonation approaches could not.
Now, it should be noted that the orbit paths of the payloads do not have to conform to the specific polar orbit depicted in the slides below. Alternative Lunar retrograde orbits and other oblique/equatorial/inclination offset orbits can be established to enhance the ability to deliver payloads to an impactor body approaching from a variety of aspect angles, and in the most rapid and low-energy-input to high kinetic payload ratio means as possible. The illustrations below depict only one type of potential prograde polar orbit, for conceptual simplicity.
notes: While the Lunar orbit is depicted as somewhat circular, the actual orbit would be elliptical. As well the relative sizes of the Moon and Earth bias towards presenting the Moon as larger and closer relative to the Earth than it really is, and both bodies larger to scale than reality. All of these are done for sake of presentation only.
Critical Advantages of ELORA over Other Interdiction Concepts/Approaches
The ELORA concept solution presents a number of advantages over currently proposed approaches:
1. Low construction cost (Provided we are working on the Moon already)
2. Repeated impacts and multiple attempts possible in quick response context (tolerates single failures)
3. No fragmentation of threat – Impactor is fine dust and spreads over an area most of the size of the bolide immediately prior to impact so that it bears less likelihood of splitting it
4. Low cost to maintain/launch/station-keep
5. Very quick deployment – System can be deployed within hours after a five-sigma track is established for the target object
6. Extremely high velocities and impact reach possible – Superior kinetic energy potential – Superior inertia imparted as compared to hydrogen core detonation
7. Modular/Scalable/’Magazine’ is cheaply and easily reload-able – the advantageous bag-by-bag method as to how it is assembled, becomes also a key strength in how it impacts the orbital body (like shotgun pellets) and reduces overall threat of fragmentation
8. Can address multiple objects at once or persistent fragments which remain after first impact, with a second fusillade
9. Can still be used with superior effectiveness for longer term intervention scenarios
10. ‘Paints’ an asteroid white (for long term intervention scenario) – Increases Yarkovsky effect – Induces cometization on impact side
11. Adds superior amount of mass to the target orbital body
12. Spread pattern (shotgun blast) or single bullet projectile and variable velocities possible – tailored to orbital body challenge. Not vulnerable to the tumbling of the target bolide (roll, pitch, yaw) as are all other technologies
13. Deflects very large orbital body mass threats compared to current conceptual approaches
14. Remaining straggler threat fragments can be independently targeted and impacted separately
15. Uses Lunar orbit angular momentum and/or Lunar/Earth slingshot effect for added kinetic energy at launch
16. Vastly superior single impactor total mass (56 x) – equivalent to 1000 – 3000 kilotons of TNT (about 2.8 – 4.2 Petajoules), in the range of 60 to 90 times as much energy as that released from the atomic bomb detonated at Hiroshima. However, unlike a nuclear warhead blast – ALL of this kinetic potential is transferred into momentum imparted to the orbital body.
17. Rapid intervention arrival time onto targeted threat
18. Potential for deployment to not be controlled by a single nation nor launch station
19. Lower chance of technology chain risk-failures/straightforward mechanisms
20. Thrusters are only directional do not have to lift anything into space, nor expend regular fuel in order to keep dynamic orbit – Less fuel vulnerable/Lower fuel requirement
21. Each impactor unit arrival provides ranging/correction for more accurate successive impacts – (shoot-shoot-look-shoot)
22. Employs the kinetic energy of the Moon’s orbit around the Earth like a pitcher’s throw in baseball
24. Uses stationary Lagrange point 1 assembly – low G and low cost to assemble/handle impactor payloads
25. Can be recaptured by Lagrange 1 assembly station and repair/maintenance done as needed
26. Low cost of assembly/launch from low G of Moon surface
27. System can be upgraded with better trajectory rockets, without having to change out the actual payload
28. System can be tested repeatedly and at a low cost. Is easy to replace the expended round.
29. Can deflect an irregular shape, long and tumbling bolide (such as 2017 Oumuamua)
30. Trojan payloads in static orbit at Earth-Lunar Lagrange 1, can be launched/slingshot by the Moon and Earth along any selected initial Lunar orbit inclination vector desired (as well as corresponding Earth slingshot inclination), to interdict objects approaching from any direction inside the celestial grid.
31. Assembly and Trojan stationing at Earth-Lunar Lagrange Point 1 allows for a very large payload to be assembled in space, yet not have to carry the rockets and large fuel required to keep orbit station around the Moon, or even worse, Earth during its assembly – wherein one would constantly have to add energy, adjusting the orbit of the payload as bag mass is added to its structure over time.
Assembly and Trojan stationing at Earth-Lunar Lagrange Point 1 allows for a very
large payload to be assembled in space, yet not have to carry the rockets and large
fuel required to keep orbit station around the Moon, or even worse, Earth during its assembly –
wherein one would constantly have to add energy, adjusting the orbit of the payload as bag mass is added to its structure over time.
Development and Phasing
While much work remains to be completed on the development phase obviously, and accordingly demands that a Moon base of operations be established (becoming only one of the reasons to mandate such a thing – so this project cannot be burdened with the full cost of establishing operations on the Moon itself), the deployment is conducted in relatively straightforward fashion, through beta testing and four deployment phases below.
2038 Beta 0 Testing – Earth based test of smaller Trojan payload station-keeping at ELL-1
2040 Beta 1 Testing – ELL-1 in situ testing of larger payload assembly/station-keeping
2043 Beta 2 Testing – Trojan to Moon orbit transition test and mock test interdiction/measure
2045 Beta 3 POC Testing – Proof of Concept with intercept of Earth satellite 2016 HO3 test interdiction
2050-54 Phase I – Establish Moon surface station infrastructure
2055 Phase II – Lunar launch station assembly/operation/test bagging & launch
2058 – 2068 Phase III – Earth-Lunar L1 Trojan impactor amassing (creating payloads)
2070 – 2075 Phase IV – Lunar Lagrange orbital array stationing/acceptance testing series
Thus, we are probably at least 40 years from being able to begin to accomplish such a feat at face value as presented herein. However, it is the opinion of this author, that eventually the best minds in this discipline will conclude that this solution is the only real way in which an emergent, 150+ meter bolide interdiction could be achieved by mankind. In the meantime, the nuclear option (distasteful as that may be) appears to be the best stop-gap measure for Earth defense with respect to smaller, more likely, PHO bolides, while we obtain the political and social will to create the elegant and ethical ELORA architecture in our binary space.
However, there is nothing to say that we cannot in the meantime, create a couple of these payloads with conventional Delta IV launches over the next two decades, place a similar smaller sized payload at Lagrange 1, and then test the concept first. In fact, we should do this. But the question will remain, will we be this bold? Or are PHO/Earth-impactors just another myth to the assuredly skeptical mind?
In the meantime, respectfully submitted for your consideration.
The Ethical Skeptic, “The Earth-Lunar Lagrange 1 Orbital Rapid Response Array (ELORA)”; The Ethical Skeptic, WordPress, 14 Sep 2019; Web, https://wp.me/p17q0e-aeh