SETV - Search for ExtraTerrestrial Visitation --Motivation

A Scientific Search for Visitation
from Extraterrestrial Probes

A New Search Model in the Quest to find ETI

Address of this site http://www.setv.org

Part 2. Motivation for SETV

The search for extraterrestrial visitation is motivated not only by the writings of other authors on the subject of interstellar probes, but also by the awareness of the progression of our own probe technology. Included in this awareness are Earth's advancements in communication technology, growing understanding of exobiology and ongoing research of new possiblities to enable travel across vast distances. Also in response to the public's growing need to understand "whether we are alone in the Cosmos."

ETI Probes and Their Missions

Using our own technological capabilities and achievements as a guide we can explore a likely range of ETI probe missions to our star system. Missions to unlock the secrets of our solar system involves the construction of machines built using available engineering technologies. With the exception of the Apollo moon landings, Space Shuttle, Mir and Skylab, all of the other physical solar system explorations have utilized robotic probes of one kind or another.

At this time our civilization has a remote presence in the solar system that includes twelve active space probes, with more than 102 space probes successfully launched since 1959.

Launching very reliable autonomous missions will ease the burden on deep space network telecommunications resources that are in high demand because of the growing numbers of robotic probes. Not needing to communicate with a probe for a year or more has value. For very long duration missions not needing to maintain contact for a long period of time is not only desirable, it's mandatory.

The hardware and software needed to build autonomous, intelligent flight systems will be complex and depend on the existence of a number of advanced technical implementation strategies. Two of these advancements are micro/nano-technology and an embedded sofware co-design programming language (Wong, 1998).

The use of more densely packed hardware structures with embedded software leads to lower volume, less mass, more diverse, and more reliable instruments. This will lead to smaller space probe designs with the full functionality of their larger and less evolved counterparts. This is the current trend in Earth space probe design, and if we extrapolate this trend to say >100 years in the future, the majority of the probes launched will be small, smart and autonomous (Tough, 1998).

But, the entire fleet of probes launched from other civilizations won't all be small, there will still be a need for larger probes especially the ones on interstellar voyages that will require added mass for fuel storage. Furthermore, large intestellar probes can act as seed pods for any smaller probes they are carrying. Indeed, there will continue to be a range of probes sizes and shapes well into the future, from nano to macro.

With this realization we should expect highly advanced probes from multiple or single ETI civilizations to exhibit a wide range of sizes and shapes. We must avoid allowing our subjective ideas about what ETI probes should look like or behave like, to cause us to dismiss certain shapes as being probes. For every geometric combination of shapes and sizes (with at least one axis of symmetry), we can imagine there probably exists an ETI probe that has a similar appearance, even including the double pie-pan or so-called "flying-saucer". ETI robotic probes will come in a diverse range of shapes, sizes and configurations, and we should not be surprised or disturbed by this. -- they will not all look like Hubble or the Mars Pathfinder.

We have already touched on our civilization's desire to launch deep space probe missions; at this time they are mainly for scientific discovery and technology validation. But once an ET civilization has overcome the major technological challenges, such as the great-distance-travel problem, what might might their probe missions be about? There are many possibities, but these four categories of ETI interstellar probe missions seem probable:

Discriminating between the types of ETI robotic probe missions and agendas, remains a matter of conjecture. All we can do is examine how we would conduct the different missions listed if we had the technology to do so.

All four mission types require the approaching probe to decelerate a substantial amount before it reaches our solar system, provided ETI probes employ propulsion systems similar to that developed on Earth or unless it is a sub-luminal relativistic fly-by, Probes can enter our solar system from just about any direction. In all likelihood they will approach from above or below the ecliptic plane where collisions with dust particles will be minimal. Also, interstellar regions with higher star densities may produce more intelligent civilizations and therefore be a source of more robotic explorations.

It is reasonable to expect that some robotic probes would place themselves into a heliocentric orbit. Remarkably, a telecopic observation of an object in 1991 may be an autonomous probe in solar orbit (Steel, 1995).

Scientific Probe Visitations

Scientific probe visitations could also arrive in the form of a complicated fly-by trajectory, since a desired survey might include all the major planetary bodies.

Military Reconnaisance

A military mission profile is self-explanatory, but could be a low probability because of the incredible expenses, logistics and enforcement burdens required (Harrison, 1997).

However, derived from Earth's history, it can be equally shown that it is the military who have the resources and the logistical support to conduct 'deep-field' exploratory efforts. Witness the US Military's Deep Space Program Science Experiment (DSPSE)

Clementine

Commercial Reconnaissance

Tourist Probe Visitations

Type II civilization

Some authors (Kuiper, 1977; Freitas, 1980) have considered that ETI probes visiting Earth would find it necessary to hide themselves from our detection systems until they have assessed our technological level or potential threat. For defensive or "first strike" purposes, we see our own need to build craft that are "stealth by design", "low observable" (LO), "stealth by intent" or "stealth through technological efficiency". We should expect LO ETI probes to be a distinct possibility. Physics mandates that there are only so many stealth strategies that can be used, even by ETI probes. Cloaking devices to mask a probe thermally, optically and from RADAR, as often depicted in science fiction, may not be necessary. Simple camouflage through mimicry works well in nature, and may be the technique of choice used by Earth visiting probes already experienced in surveillance. One author, through his own instrumented observation study, suggested that ETI surveillance probes may sit stationary over a certain region appearing as "pseudo-stars" (Rutledge, 1981); unless one was very familiar with the night time star positions, magnitudes and motions, the probe would go unnoticed. Another camouflage technique may be entering the atmosphere with either the look and trajectory of a meteor, or hidden within a meteor shower. The observed phenomenon of "dark meteors" (Malau, 1995; McBeath 1995,1996) may be a technique used by ETI probes to pass through the atmosphere on a meteoric trajectory, but without any associated optical train or signature. Another technique may be to mimic our commercial aircrafts' aggregate features (flashing red-green lights, sounds, speeds, motions), with just enough "thinly veiled" accuracy, to only draw a quick and uninterested glance (Cornet, 1996). Of course, this entire discussion of ETI probe low observability behaviors assumes that humanity itself is the subject of interest and advoidance; this may not be the case at all, but it is a realistic place to begin.

Probe missions related to extended environmental surveys would be considered "low risk" if they were confined to isolated, sparsely inhabited regions, such as deserts or polar ice caps, where little or no evidence of humans or terrestrial technology is found. A highly advanced probe might employ an adaptive multi-level risk program to avoid danger. Observed behaviors employing hazard avoidance, learned through prior encounter experiences, will probably make a probe appear intelligently controlled. This could lead to a misperception that the probe contains living occupants, intelligent according to our anthropocentric understanding of the concept. The size, shape and/or behavior of a highly advanced ETI probe might be 'seen' as being crewed and operated by intelligent ETs. For example, in 1988 the un-crewed Russian space shuttle Energia-Buran was launched into orbit and successfully landed under complete computer control (Jenkins, 1996). Watching it come in for a landing an onlooker might conclude it was 'intelligently' piloted, and might even imagine seeing a cosmonaught at the controls. If ETI probes do visit Earth, to avoid prospective dangers they will probably attempt to minimally interact with our local environment. Even so, they will very likely be detectable using contemporary sensing technologies.

Possibility of Life Beyond Earth

Environments in which life can exist are more abundant than previously thought

NASA as well as other science institutions are conducting studies of "harsh environment life evolution." During the past couple of decades, scientists have learned that tiny organisms can live in places on Earth that were thought to be inhospitable to life. This makes it more likely that microscopic life might exist on other planets even if they don't have the sunlight needed for the photosynthesis on which Earth's plants and animals depend. It seems that if liquid water is available, life as we know it, can thrive almost anywhere, provided there is a source of energy. On Earth, for instance, microorganisms live in sea caves where it is very dark and the energy needed for life comes from sulfur-based chemistry.

Environments previously thought incapable of supporting life are now being found which support heretofore unknown life with much thriving diversity. Organisms living "10s of centimeters" from thermally intense (very hot) volcanic fumerals (underwater volcano vents) on the bottom of Earth's deep oceans and under immense pressure. Recently NASA exobiologsts working in the Antartica, possibly the coldest area on Earth, are finding life. Scientists are using Antartica as a 'test-bed' laboratory --a model to help researchers understand the possibilities of how life may exist in the far reaches of the Solar System and our Galaxy. Scientists looking for evidence of life -- past or present -- on other planets or moons find Antartica is fascinating. "It's a test bed and training ground for the accelerating search for extraterrestrial organisms sponsored by the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF)." The question repeatedly raised, "If life can exist in the extremely harsh evironments on Earth, why can't life develop elsewhere in the Solar System, galaxy and beyond?"

Life may be able to 'jump' from planet to planet

Date sent: Fri, 19 Nov 1999 14:08:16 -0500

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From:      Larry Klaes lklaes@bbn.com
Subject:          Bacteria: The Ideal Astronauts?

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>From NASA Watch and The Astrobiology Web:

19 November 1999: Bacteria: The Ideal Astronauts?

In August 1996 David McKay and Everett Gibson from NASA JSC stunned the world by publishing a paper in Science magazine that reported evidence of fossilized microorganisms found within the ALH84001 meteorite that came to Earth from Mars. In the ensuing months and years, interest in life on Mars - and elsewhere - was rekindled.

The notion that rocks could be blasted off of one planet by an asteroid impact and land upon another was not exactly new. But could life be carried within a rock between planets and survive the trip to take root on another world? The trip would not necessarily be all that smooth.

Enter Deinococcus radiodurans. In an article in today's Science magazine, researchers at The Institute for Genomic Research (TIGR) report that they have determined the entire genetic sequence of this bacterium. D. radiodurans can survive gamma radiation exposures of 1.5 million rads which literally blast its DNA apart.

It then reassembles its DNA all by itself with no apparent ill effects. This organism can also be completely dried out and then be revived and can survive doses of ultraviolet radiation that would kill most other forms of life. Sounds like the perfect organisms to send on a long trip inside a rock between planets! Indeed, it is so robust that it is being considered for use in cleaning up radioactive waste dumps.

Examples of life on Earth living in extreme conditions include:

Hottest: 235.4 �F --bacteria from deep sea vents

Coldest: 5 �F --microalgae in Antarctic rocks

Deepest: Bacteria, two miles underground in rocks

Most acidic: Unclassified organisms growing on gypsum in caves at pH 0

Highest radiation: 5 million rads --Deinococcus radiodurans (bacteria)

Saltiest: Bacteria, 30 percent salt environment

Deepest and Highest pressure: 1200 atm --at bottom of Marianas Trench (ocean)

Farthest: Moon, Streptococcus mitus (from human source) from Surveyor III camera after three years unprotected on lunar surface

Source: NASA

Extrasolar Planets Discovered Outside Earth's Solar System

Exoplanets imaged by NASA's Hubble Space Telescope (

HST

OTHER

New Earth Size Planet Found

An article by:

Dr. David Whitehouse, BBC News OnlineScience Editor

A chance alignment between two stars may have allowed astronomers to detect the first Earth-sized planet found outside our solar system.

In June 1998 observations made at the Mount Stromlo Observatory in Australia and the Mount John Observatory in New Zealand detected a star near the centre of our galaxy becoming abnormally bright. The brightening occurred because of the so-called gravitational lensing effect. This happens when another star passes directly between the distant star and ourselves. Its gravity acts like a lens bending and amplifying the light from the distant object. The observatories were looking for just such an event.

By studying the way the distant object's light rises and falls, astronomers could determine the distant star appeared to be larger than our own Sun.
A detailed analysis of the data suggests the light-curve can only be explained if it has a planet orbiting it.

If so then it must be the smallest planet discovered orbiting another star - possibly as small as the Earth.

Different Techniques
In the past few years astronomers have discovered about 20 planets orbiting some of the nearest stars to our Sun using different techniques. All of them however have been massive and are probably more like the gas giant Jupiter than the small, rocky Earth.

This new planetary system would be unique in not having any gas giant planets. A detailed analysis has been submitted for publication in the Astrophysical Journal.

More recent observations of another star brightening suggest the same group of astronomers may have discovered a planet in a large orbit around two close stars.

BBC News, 99.09.17