A Clockwork Rover for Venus
A good watch can take a beating and keep on ticking.
With the right parts, can a rover do the same on a planet like Venus?
A concept inspired by clockwork computers and World War
I tanks could one day help us find out. The design is being explored
at NASA's Jet Propulsion Laboratory in Pasadena, California.
The Automaton Rover for Extreme Environments (AREE) is funded
for study by the NASA Innovative Advanced Concepts program.
The program offers small grants to develop early stage technology,
allowing engineers to work out their ideas.
AREE was first proposed in 2015 by Jonathan Sauder,
a mechatronics engineer at JPL. He was inspired by mechanical
computers, which use levers and gears to make calculations rather
than electronics.
By avoiding electronics, a rover might be able to better explore Venus.
The planet's hellish atmosphere creates pressures that would crush most submarines.
Its average surface temperature is 864 degrees Fahrenheit (462 degrees Celsius),
high enough to melt lead.
Steampunk computing
Mechanical computers have been used throughout history, most often as
mathematical tools like adding machines. The most famous might be
Charles Babbage's Difference Engine, a 19th century invention for calculating
algebraic equations. The oldest known is the Antikythera mechanism,
a device used by ancient Greeks to predict astronomical phenomena like eclipses.
Mechanical computers were also developed as works of art. For hundreds of years,
clockwork mechanisms were used to create automatons for wealthy patrons.
In the 1770s, a Swiss watchmaker named Pierre Jaquet-Droz created "The Writer,"
an automaton that could be programmed to write any combination of letters.
Sauder said these analog technologies could help where electronics typically fail.
In extreme environments like the surface of Venus, most electronics will melt
in high temperatures or be corroded by sulfuric acid in the atmosphere.
"Venus is too inhospitable for kind of complex control systems you have
on a Mars rover," Sauder said. "But with a fully mechanical rover,
you might be able to survive as long as a year."
Wind turbines in the center of the rover would power these computers,
allowing it to flip upside down and keep running.
But the planet's environment would offer plenty of challenges.
The extreme planet
No spacecraft has survived the Venusian surface
for more than a couple hours.
Venus' last visitors were the Soviet Venera and Vega landers.
In the 1970s and 1980s, they sent back a handful of images
that revealed a craggy, gas-choked world.
"When you think of something as extreme as Venus, you want
to think really out there," said Evan Hilgemann, a JPL engineer working
on high temperature designs for AREE. "It's an environment we don't
know much about beyond what we've seen in Soviet-era images."
Sauder and Hilgemann are preparing to bake mechanical prototypes,
allowing them to study how thermal expansion could affect
their moving parts. Some components of the Soviet landers had
actually been designed with this heat expansion in mind:
their parts wouldn't work properly until they were heated
to Venusian temperatures.
Tank treads for Venus
AREE includes a number of other innovative design choices.
Mobility is one challenge, considering there are so many unknowns
about the Venusian surface. Sauder's original idea was inspired
by the "Strandbeests" created by Dutch artist Theo Jansen.
These spider-like structures have spindly legs that can carry their
bulk across beaches, powered solely by wind.
Ultimately, they seemed too unstable for rocky terrain. Sauder started
looking at World War I tank treads as an alternative. These were built
to roll over trenches and craters.
Another problem will be communications. Without electronics,
how would you transmit science data? Current plans are inspired
by another age-old technology: Morse code.
An orbiting spacecraft could ping the rover using radar. The rover
would have a radar target, which if shaped correctly, would act like
"stealth technology in reverse," Sauder said. Stealth planes have special
shapes that disperse radar signals; Sauder is exploring how to shape
these targets to brightly reflect signals instead. Adding a rotating shutter
in front of the radar target would allow the rover to turn the bright, reflected
spot on and off, communicating much like signal lamps on Navy ships.
Now in its second phase of NIAC development, the JPL team is selecting parts
of the AREE concept to be refined and prototyped. Team members hope
to flesh out a rover concept that will eventually be able to study
the geology of Venus and perhaps drill a few samples.
For more information about AREE, go to:
https://www.nasa.gov/directorates/spacetech/niac/2017_Phase_I_Phase_II/Automaton_Rover_Extreme_EnvironmentsNews Media Contact
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov 2017-228
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25 August 2017
Earlier this month, radio dishes from three deep-space networks
combined to catch faint ‘survival’ whispers from one of ESA’s Mars
orbiters, underlining the value of international collaboration
for exploring the Red Planet.
For the first time ever, deep-space ground stations from ESA, NASA
and Russia’s Roscosmos joined together, on 13 August, to receive
ultra-faint signals from ESA’s ExoMars Trace Gas Orbiter, now circling Mars.
Engineers carefully designed the test to probe the limits of what their
ground stations could achieve, and confirm that all three could catch
signals from the orbiter should it ever switch itself into the low-power,
minimal ‘survival mode’.
This special mode can occur if a software or hardware glitch
causes multiple onboard computer reboots.
The test took place just as Mars was moving from the opposite
side of the Sun, where it is at its greatest distance from us.
This meant that ExoMars was more than 397 million km from the
three dishes, a situation that occurs only every two years, when
communications are at their most difficult.
Big Iron listens in
The ExoMars Trace Gas Orbiter is on a multiyear mission to understand
the tiny amounts of methane and other gases in Mars’ atmosphere that
could be evidence for possible biological or geological activity.
Trace Gas Orbiter at Mars
As expected, NASA’s 70 m-diameter dish at Canberra, Australia,
could receive the ultra-weak signals and transmit commands.
Likewise, ESA’s 35 m antenna at New Norcia, Australia, picked up
the call and demonstrated that it could also transmit commands
to ExoMars – but only at 10 bits/s. This would be sufficient in
an emergency to upload instructions to recover the craft.
In addition to the low rate, the New Norcia station used only its low-power
amplifier to transmit, and there was poor weather over the station
in Western Australia.
“If a problem is going to happen with our orbiter or, in future,
our rover, at Mars, we want to have confidence that we can
communicate even under the worst possible conditions of power
and distance, and this test simulated that very well,” says spacecraft
operations manager Peter Schmitz.
Testing success
The RT-64 radio-telescope at Kalyazin, Russia, is supporting
the ESA-Roscosmos ExoMars mission.
Kalyazin 64-m dish
The real prize came with the Russian 64 m dish
at Kalyazin, some 200 km north of Moscow. Originally designed
as a radio telescope, it has been upgraded to support
the ESA–Roscosmos ExoMars missions.
“Kalyazin was able to receive the signal, demonstrating that
all three networks can support ExoMars under the worst-case scenario,
when Mars is at its furthest distance and the signals are at their weakest,”
said Daniel Firre, ESA’s ground station engineer responsible
for cooperation with other agencies.
“And the test was all the more impressive given the extreme weakness
of the signals. These had a power upon receipt at Earth some
1000 times less than we would receive from a typical mobile phone
transmitting from the Moon.”
-------------------------------------------
NASA Satellite Images Show Evolution of Hurricane Harvey
Hurricane Harvey as seen by the AIRS infrared instrument on NASA's
Aqua satellite at 3 p.m. CDT on Wednesday, Aug. 23 (left) and
at 3 a.m. CDT on Friday, Aug. 25 (right). The darker the color,
the colder and higher the clouds and the stronger the thunderstorms.
Credit: NASA/JPL-Caltech
› Larger view
Hurricane Harvey continues to churn toward the Texas coast,
and is expected to make landfall as a major hurricane sometime late
Aug. 25 or early Aug. 26, according to the National Hurricane Center.
It would be the first major hurricane to make landfall in the United States since 2005.
The rapid intensification of Harvey is depicted in this set of false-color
images from NASA's Atmospheric Infrared Sounder (AIRS) and
Advanced Microwave Sounding Unit (AMSU) instruments
on NASA's Aqua satellite. The earlier images were acquired
at 3:05 p.m. CDT (19:05 UTC) on Wednesday, Aug. 23,
when Harvey became a tropical storm soon after crossing from
the Yucatan Peninsula over warm waters in the Gulf of Mexico.
The later images were acquired at 2:59 a.m. CDT (7:59 UTC)
on Friday, Aug. 25, when Harvey was a Category 2 hurricane.
Warm colors in the infrared images (red, orange, yellow) show areas
with little cloud cover. Cold colors (blue, purple) show areas covered
by clouds that have developed sufficiently to reach high, cold altitudes,
creating strong thunderstorms. The darker the color, the colder
and higher the clouds and the stronger the thunderstorms.
In the microwave images, blue indicates areas of heavy rainfall beneath
the coldest clouds.
These images illustrate how, over a 36-hour period, Harvey became
more organized (shown by its more circular shape and more-developed rain
bands in the later images), intensified (shown by the growing area of blue
and purple colors in the infrared) and moved northwest toward Texas.
The microwave images show how the areas with rain have grown
in area and intensity.
Together, these two instruments give a detailed picture of the atmospheric
conditions in and around a storm like Harvey. These observations
are used by weather forecasters to predict how Harvey will move
and change strength.
For more information on AIRS, visit:
https://airs.jpl.nasa.gov/ News Media Contact
Alan Buis
Jet Propulsion Laboratory, Pasadena, California
818-354-0474
alan.buis@jpl.nasa.govWeather and climate from space
https://airs.jpl.nasa.gov/CERTAINS Décès DU 25 AOÜT
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1572 : Pierre de La Place, magistrat, jurisconsulte, philosophe, historien et écrivain protestant français (° vers 1520).
1774 : Niccolò Jommelli, compositeur italien (° 10 septembre 1714).
1776 : David Hume, philosophe britannique (° 7 mai 1711).
1819 : James Watt, ingénieur écossais (° 19 janvier 1736).
1822 : William Herschel, astronome britannique (° 15 novembre 1738).
1865 : Louis Isidore Duperrey, officier de marine français (° 21 octobre 1786).
1867 : Michael Faraday, physicien et chimiste britannique (° 22 septembre 1791).
1870 : Philémont de Bagenrieux de Lanquesaint, homme politique belge (° 8 juin 1802).
1894 : Victoire Rasoamanarivo, laïc malgache béatifiée en 1989.
1900 : Friedrich Nietzsche, philosophe allemand (° 15 octobre 1844).
1904 : Henri Fantin-Latour, peintre français (° 14 janvier 1836).
1908 : Henri Becquerel, physicien français, prix Nobel de physique en 1903 († 15 décembre 1852).
1936 : Ferdinand Gaillard, artiste lyrique français (° 11 janvier 1876).
1939 : Babe Siebert, hockeyeur sur glace professionnel canadien (° 14 janvier 1904).
1957 : Umberto Saba, écrivain et poète italien (° 9 mars 1883).
1967 : Paul Muni, acteur américain (° 22 septembre 1895).
1976 : Eyvind Johnson, écrivain suédois, prix Nobel de littérature en 1974 (° 29 juillet 1900).
1979 : Stan Kenton, pianiste, compositeur et chef d’orchestre de jazz américain (° 19 février 1912).
1980 : Gower Champion, danseur, chorégraphe et acteur américain (° 22 juin 1919).
1984 : Truman Capote, écrivain américain (° 30 septembre 1924).
Viktor Chukarin (Віктор Чукарін), gymnaste soviétique, plusieurs fois médaillé olympique en 1952 et 1956 et au championnat du monde en 1954 (° 9 novembre 1921).
1985 : Samantha Smith, écolière américaine, ambassadrice de bonne volonté en Union soviétique (° 29 juin 1972).
1988 : Françoise Dolto, médecin, pédiatre et psychanalyste française (° 6 novembre 1908).
1990 : Morley Edward Callaghan, romancier, nouvelliste et animateur de radio et de télévision canadien (° 22 septembre 1903).
1991 : Alessandro Dordi, prêtre italien assassiné par les terroristes du Sentier lumineux au Pérou2.
1997 : Robert Pinget, écrivain français (° 19 juillet 1919).
2000 : Carl Barks, dessinateur américain (° 27 mars 1901).
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2001 : Aaliyah (Aaliyah Dana Haughton, dite), chanteuse et actrice américaine (° 16 janvier 1979).
Carl Brewer, joueur de hockey sur glace canadien (° 21 octobre 1938).
John Chambers, maquilleur de cinéma américain (° 12 septembre 1923).
Philippe Léotard, comédien français (° 28 août 1940).
2004 : Marcelo González Martín, prélat espagnol (° 16 janvier 1918).
2007 : Raymond Barre, économiste et homme politique français, Premier ministre de 1976 à 1981 (° 12 avril 1924).
Édouard Gagnon, prélat canadien (° 15 janvier 1918).
2009 : Edward Moore Kennedy, homme politique américain, sénateur du Massachusetts de 1962 à 2009 (° 22 février 1932).
2010 : Denise Legrix, écrivaine et peintre française (° 16 mai 1910).
2012 : Neil Armstrong, astronaute américain, premier homme à avoir marché sur la Lune (° 5 août 1930).
2014 : Marcel Masse, homme politique québécois (° 27 mai 1936).
Erwan Chuberre, romancier français (° 9 mars 1971).
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