We Are Made of Stardust

Throughout most of human history, people considered themselves and the planet they lived on as being apart from the rest of the universe. After all, the heavens were clearly unreachable and therefore had to remain the abode of the deities found in the numerous mythologies that enriched ancient civilizations. It is only with the rise of modern astronomy, exobiology, and space technology that scientists have been able to investigate properly the chemical evolution of the universe. And the results...

The Theory and Operation of Self Replicating Systems

The brilliant Hungarian-American mathematician John von Neumann (1903-57) was the first person to consider the problem of self-replicating systems seriously. His book on the subject, Theory of Self-reproducing Automata, was edited by a colleague, Arthur W. Burks (1915- ), and was published posthumously in 1966 almost a decade after von Neumann's untimely death due to cancer. Von Neumann became interested in the study of automatic replication as part of his wide-ranging interests in complicated...

Habitable Worlds around Distant Stars

An extrasolar planet is a planet that belongs to a star other than the Sun. Modern astronomers use two general methods to detect extrasolar planets direct involving a search for telltale signs of a planet's infrared emissions and indirect involving precise observation of any perturbed motion (for example, wobbling) of the parent star or any periodic variation in the intensity or spectral properties of the parent star's light. Growing evidence of planets around other stars is helping astronomers...

Control of Self Replicating Systems

Whenever engineers discuss the technology and role of self-replicating systems, their conversations inevitably turn to the interesting question What happens if a self-replicating system (SRS) becomes out of control Before human beings seed the solar system or interstellar space with even a single SRS unit, engineers and mission planners should know how to pull an SRS unit's plug if things grow out of control. Some engineers and scientists have already raised a very legitimate concern about SRS...

Preventing Back Contamination

There are three fundamental approaches toward handling extraterrestrial samples to avoid back contamination. First, scientists could sterilize a sample while it is en route to Earth from its native world. Second, they could place it in quarantine in a remotely located, maximum-confinement facility on Earth while scientists examine it closely. Finally, they could also perform a preliminary hazard analysis (called the extraterrestrial protocol tests) on the alien sample in an orbiting quarantine...

Arecibo Interstellar Message

To help inaugurate the powerful radio radar telescope of the Arecibo Observatory in the tropical jungles of Puerto Rico, an interstellar message of friendship was beamed to the fringes of the Milky Way galaxy. On November 16, 1974, this interstellar radio signal was transmitted toward the Great Cluster in Hercules (Messier 13 or M13, for short), which lies about 25,000 light-years away from Earth. The globular cluster M13 contains about 300,000 stars within a radius of approximately 18...

Smarter Robots to the Red Planet

NASA's planned Phoenix Mars Scout will land in icy soils near the north polar permanent ice cap of the Red Planet and explore the history of water in these soils and any associated rocks. This sophisticated space robot serves as NASA's first exploration of a potential modern habitat on Mars and opens the door to a renewed search for carbon-bearing compounds, last attempted with the Viking 1 and 2 lander spacecraft missions in the 1970s. The Phoenix spacecraft is currently in development and...

Summary of Extrasolar Planet Hunting Techniques

The quest for extrasolar planets is one of the most interesting areas within modern astronomy. But how can astronomers find planetary bodies around distant stars In their search for extrasolar planets, scientists employ several important techniques. These techniques include pulsar timing, Doppler spectroscopy, astrometry, transit photometry, and gravitational microlensing. Astronomers accomplished the first widely accepted detection of extrasolar planets (namely, pulsar planets) in the early...

Planetary Quarantine Program

NASA started a planetary quarantine program in the late 1950s at the beginning of the U.S. civilian space program. This quarantine program, conducted with international cooperation, was intended to prevent, or at least minimize, the possibility of contamination of alien worlds by early space probes. At that time, scientists were very concerned about the issue of forward contamination. In this type of extraterrestrial contamination, terrestrial microorganisms, hitchhiking on initial planetary...

NASAs Viking Project

The Viking Project was the culmination of an initial series of U.S. missions to explore Mars in the 1960s and 1970s. This series of interplanetary missions began in 1964 with Mariner 4, continued with the Mariner 6 and 7 flyby missions in 1969, and ended to date with the Mariner 9 orbital mission in 1971 and 1972. Viking robot spacecraft were designed as a complement pair one to orbit Mars and one to land and operate on the surface of the Red Planet. Reflecting the aerospace engineering...

Planetary Engineering

Planetary engineering, or terraforming as it is sometimes called, is the large-scale modification or manipulation of the environment of a planet to make it more suitable for human habitation. In the case of Mars, human settlers would probably seek to make its atmosphere more dense and breathable by adding more oxygen. Early Martians would probably also attempt to alter the planet's harsh temperatures and to modify them to fit a more terrestrial thermal pattern. Venus represents an even larger...

Voyager Interstellar Mission VIM

Voyager Drawing

As the influence of the Sun's magnetic field and solar wind grow weaker, both Voyager robot spacecraft eventually will pass out of the heliosphere and into the interstellar medium. Through NASA's Voyager Interstellar Mission VIM which began officially on January 1, 1990 , the Voyager 1 and 2 spacecraft will continue to be tracked on their outward journey. The two major objectives of the VIM are an investigation of the interplanetary and interstellar media and a characterization of the...

Designing an Interstellar Probe

If the development of human crew-carrying starships proves to be an impossible technical feat during the next few centuries, the human race can still search other star systems for alien life and spread terrestrial, carbon-based life around the galaxy with the help of sophisticated robot spacecraft. A modest effort might even be started at the end of this century with a decision by humans to launch one or more interstellar probes. Then, sometime in the 22nd century, our descendants might make...

Bioclean Room

A bioclean room, or clean room, is any enclosed area where there is control over viable and nonviable particulates in the air with temperature, humidity, and pressure control as required to maintain specified standards. A viable particle is a particle that will reproduce to form observable colonies when placed on a specified culture medium and when incubated according to optimum environmental conditions for growth after collection. A nonviable particle will not reproduce to form observable...

Androcells Everywhere

The androcell is a concept that the German-American rocket scientist Krafft A. Ehricke 1917-84 introduced in the 1970s. According to Ehricke, the androcell would be a very large, humanmade new world an independent, self-contained human biosphere not located on any naturally existing celestial object. In his strategic vision, such humanmade miniworlds or planetellas would use mass far more efficiently than the natural worlds of the solar system, which formed out of the original solar nebular...

Mars Outpost and Surface Base Concepts

For automated Mars missions, the spacecraft and robotic surface rovers generally will be small and self-contained. For human expeditions to the surface of the Red Planet, however, two major requirements must be satisfied life support habitation and surface transportation mobility . Habitats, power supplies, and life-support systems will tend to be more complex in a permanent Martian surface base that must sustain human beings for years at a time. Surface mobility systems will also grow in...

Water Hole

Water hole is a SETI term used to describe a narrow portion of the electromagnetic spectrum that appears to be especially appropriate for interstellar communications between emerging and advanced civilizations. This band lies in the radio frequency RF part of the spectrum between 1,420 megahertz MHz frequency 8.3-inch 21.1-cm wavelength and 1,660 megahertz MHz frequency 7.1-inch 18-cm wavelength . Hydrogen H is abundant throughout interstellar space. When hydrogen experiences a spin-flip...

Dyson Sphere

The Dyson sphere is a huge, artificial biosphere that is created around a star by an intelligent species as part of its technological growth and expansion within an alien solar system. This hypothesized giant structure would probably be formed by a swarm of artificial habitats and miniplanets that are capable of intercepting essentially all the radiant energy from the parent star. The captured radiant energy would be converted for use through a variety of techniques such as living plants,...

Extraterrestrial Catastrophe Theory

For millions of years, giant, thundering reptiles roamed the lands, dominated the skies, and swam in the oceans of a prehistoric Earth. Dinosaurs reigned supreme. Then, quite suddenly, some 65 million years ago, they vanished. What happened to these giant creatures and to thousands of other ancient animal species From archaeological and geological records, scientists know that some tremendous catastrophe occurred about 65 million years ago on this planet. It affected life more extensively than...

Laboratory Hypothesis

The laboratory hypothesis is a variation of the zoo hypothesis response to the Fermi paradox. This particular hypothesis stipulates that the reason human beings cannot detect or interact with technically advanced extraterrestrial civilizations in the Milky Way galaxy is because the intelligent aliens have set the solar system up as a perfect' laboratory. The hypothesized alien scientists and researchers want to observe and study humans but do not want us to be aware of or influenced by their...

Some Speculations about the Nature of Extraterrestrial Civilizations

According to some scientists, intelligent extraterrestrial ET civilizations in the galaxy might be conveniently characterized as falling into one of several basic levels of societal development or technology use. In SETI activities, one of the most widely used scales is the three types of ET civilizations that were introduced in 1964 by the Russian astronomer Nikolai Semenovich Kardashev 1932- . While examining the issue of interstellar information transmission by extraterrestrial...

Green Bank Telescope

On November 15, 1988, the original 300-foot 91.5-m Green Bank radio telescope collapsed due to a sudden failure of a key structural element. This unexpected loss of the National Radio Astronomy Observatory NRAO 's major observing facility resulted in the construction of a replacement project, called the Robert C. Byrd Green Bank Telescope GBT . NRAO operates the Green Bank Telescope, which is the world's largest fully steerable single aperture antenna. In addition to the GBT, there are several...

Deep Space Network DSN

The majority of NASA's scientific investigations of the solar system are accomplished through the use of robot spacecraft. The Deep Space Network DSN provides the two-way communications link that guides and controls these spacecraft and brings back the spectacular planetary images and other important scientific data they collect. The DSN consists of telecommunications complexes strategically placed on three continents providing almost continuous contact with scientific spacecraft traveling in...

First Human Crewed Expedition to Mars

The human-crewed expedition to Mars will most likely occur before the midpart of this century possibly as early as 2035. Current expedition scenarios suggest a 600- to 1,000-day duration mission that most likely will start from Earth orbit, possibly powered by a nuclear thermal rocket. A total crew size of as many as 15 astronauts is anticipated. After hundreds of days of travel through interplanetary space, the first Martian explorers This artist's rendering shows two astronaut-scientists one...

Titan

Titan Atmosphere Artist

With its rich atmosphere of organic molecules, for many exobiologists, Titan, the largest moon of the planet Saturn, is a dream natural laboratory. Titan's atmosphere is composed of nitrogen N2 and methane This artist's rendering shows a proposed ice-penetrating cryobot background and a submersible hydrobot foreground an intriguing advance robot combination that could be used to explore the suspected ice-covered ocean on Jupiter's moon Europa. In this scenario, a lander robot would arrive on...

Some Interesting Facts about Enceladus

Enceladus is a moon of Saturn that was discovered in 1789 by the British astronomer Sir William Herschel 1738-1822 . This relatively small moon has a diameter of approximately 310 miles 500 km and orbits around Saturn at a distance of 147,898 miles 238,020 km with a period of rotation of 1.37 days. The surface of Enceladus is dominated by fresh, clean ice, giving the moon an albedo of almost one. Because Enceladus reflects almost 100 percent of the incident sunlight, the moon has a surface...