Saturday, March 03, 2007

Robotic Operations

Survey

---Service transponder

---Measure surface (geodetics)

---Analyze surface

---Analyze subsurface

Note online source document: New breed of robots to explore the planets
Text modified to reflect my readability style. No intent to change content.

A skateboard-size Mars robot, Sojourner, ventured around the Red Planet and provided a lot of useful data. Sojourner is a forerunner of NASA's futuristic robo-critters, including:
*A four-legged robot the size of a cigar box will hop around an asteroid like a grasshopper.
*A snakelike tube will drill thousands of feet into the Martian crust, seeking subsurface water and, perhaps, microbes.
*A two-legged "walking" robot under development at NASA's Ames Research Center (ARC) in Mountain View, CA.
*On Jupiter, a hot-air balloon with TV cameras would pass above multicolored mega-hurricanes bigger than Earth.
*Mini- "helicopters" can maneuver through the Martian atmosphere.
*A robotic "submarine" can plunge into an icy ocean on Europa, a moon of Jupiter, and seek weird life forms in its dark depths.
Some robots would be far smaller than today's space probes. The drive toward smaller robotic probes was part of then NASA Administrator Daniel Goldin's push for "smaller, cheaper, faster" missions to get the best value out of NASA's ever-diminishing post-Cold War budget.
"The lighter the payload, the lower the cost of launch." says Brian Wilcox, supervisor of the robot vehicles group at Jet Propulsion Laboratory (JPL) in Pasadena. "A Delta launch vehicle costs about $60 million."


NANOBOTS TO THE RESEARCH. If NASA's robotic program survives Congressional budget cuts, a new breed of "astronauts" will soar skyward in the next decade or two - made of metal and microchips, and as small as cigar boxes or smaller. Because of their diminutive size, they have been dubbed nanorobots or "nanobots." ( "Nano" is the scientific prefix that refers to billionths of something. For example, a nanometer is a billionth of a meter.)
Conceivably, NASA could cram numerous nanobots aboard a single launch vehicle, then send them to Mars or other worlds
(like asteroids). At their destination, they would form a "robot colony," per Hamid Berenji, ARC systems engineer . The colony could scout out in different directions to survey the entire asteroid. Such fleets would be mechanical versions of Lewis and Clark, famous explorers who led an expedition to the American northwest.
At ARC, Berenji and biomechanical-electronics engineer, Ron Jacobs, are developing a two-legged robot that walks with a normal walking motion. It could navigate over rough terrain, such as the rock-strewn, crater-scarred surface of Mars. Berenji and Jacobs work for a NASA contractor, Intelligent Inference Systems Corp. of Sunnyvale, CA.
ARC researchers are developing a spherical robot that can float aboard a spaceship and fly around, propelled by small propellers. Its purpose: to allow a busy astronaut to check on an experiment in another lab, or a potentially dangerous situation - say, a gas leak - without getting directly in harm's way.

HOP-A-LONG. JPL has worked on a "hopping" robot. It's part of a joint U.S.-Japan space mission (July 2002??). Destination is a small asteroid, diameter of about six football fields, with very low gravity, about 1/100,000ths that of Earth. The robot will have to move very gingerly about its surface, lest it accelerate off the asteroid into space. "Escape velocity" for the asteroid is 3 feet per second (several miles per second for Earth). That's about strolling pace for a long-legged adult.
The nanobot would "hop" by gently compressing its "legs" together, allowing it to "spring" upward at a speed of 8 inches per second. "We could hop 100 or more meters (more than 300 feet) into the sky," Wilcox says.

THE BIG CHILL. Nanobots would have an inherent disadvantage: They cool easily. Smaller spheres cool faster than larger ones because they display much more surface area (to radiate heat) per same amount of volume. This is one reason why smaller celestial objects like asteroids and many moons have no active volcanoes: Their internal heat escaped to space long ago.
Also, the nanobot will be too small to carry an on-board heater. Scientists could give it heat shields to keep it warm (as well as to protect it from high-speed interstellar particles called galactic cosmic rays), but the added weight of shielding would obviate the advantage of its small size.
Thus, the JPL team is trying to develop nanobots whose electronics can endure the temperature extremes of deep space - which range from boiling-hot daytimes to nighttime temperatures about 300 degrees below zero Fahrenheit, far colder than the South Pole.
NASA recently announced plans to launch into Earth orbit three small satellites, dubbed the "Nanosat Constellation Trailblazer" mission. Each satellite would be an octagon 8 inches high and 16 inches long. Among other things, the minisatellites
(hopefully launched in 2003)
will test the ability of new electronics and other equipment to survive "near the boundary of Earth's protective magnetic field," agency spokesman Donald Savage said.
Robotic balloons or "aerobots" are also under development. These could float through the atmospheres of Mars, Venus, Jupiter and Titan, a moon of the ringed planet Saturn.
JPL scientists are designing a Venusian aerobot that would float more than 30 miles above the searing-hot planet. The probe would drop TV-equipped instruments or
"sondes" toward the surface, snapping pictures as they dropped toward the surface, which is typically veiled by an extremely dense atmosphere.
Another possibility is a balloon that would periodically lower its instruments to the Venusian surface, briefly take measurements, and intermittently rise to cool off. Otherwise the instruments would melt on the extremely hot surface, which, according to JPL's Jim Cutts, is hot enough to melt lead.
In one daring mission, a balloon would lower toward the Venusian surface, allowing the robot to gather rock samples. Then the balloon and robot would rise into the sky, where an on-board rocket would fire the rock samples into orbit. There it would rendezvous with another rocket, which would ferry the samples to Earth.

BURROWING FOR DATA. One of the strangest proposed robots is a worm-like device. It would drill into the Martian crust, like a super-worm. "We are building a (worm-like) device a few inches in diameter and 3 to 6 feet long, and 1 1/4 inches in diameter," says Wilcox. Ideally, it could drill at least a mile into the Martian crust to look for buried microbes in ground water. (Since most asteroids are less then a mile in diameter, this type of device would be an excellent subsurface analyzer.)
The robot would connect to the surface via long wires and capillary tubes. The former would transmit electric power from solar panels on the surface.
(Most asteroids would need another power source, perhaps nuclear reactors.)
The tubes - filled with liquefied carbon dioxide condensed from the Martian atmosphere - would pump subsurface grains (perhaps even microbes) back to the surface. The "worm" would drill through the crust by repeatedly firing a tungsten "hammer" into the rock. Its technical name is "robotic subsurface explorer" or SSX.

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