----- Original Message ----- From: Larry Kellogg Sent: Sunday, January 04, 2004 8:51 PM To: [EMAIL PROTECTED] Subject: [lunar-update] Back-seat drivers on another planet One more for today, then I will go watch TV and let you think about going to
the Moon, Mars, and Beyond.
Sangad, my Thai wife, watches satellite TV from Bangkok and sometimes the
sound and picture are not quite in sync. Mouths move, then spoken Thai. My
understanding of Thai is not all that good and trying to watch mouths moving
while figuring out what is being said can give one a head ache.
Now think about trying to drive your kids RC Controlled car down the street
where you make a move of the joy stick and the car reacts almost
immediately. Not too bad. Add a second and a half to seeing it react to
your shove and you are driving on the Moon. Add 9.5 to 13.1 minutes delay
for the car to react and then again that time for to see what happened and
you are driving the car into a rock on Mars.
http://ssd.jpl.nasa.gov/cgi-bin/eph
So forget real-time joy stick control and figure out how you are going to
move faster than a snail on Mars.
Think of Hands Off driving and hope your rover has some smarts built in.
Was that a rock I drove over or a dead rabbit? (Wouldn't want a hit an run
accident, although finding a dead rabbit would be interesting. :-)
Tell your robot driver to go out but be back by Sun down and take it easy
while you are out of communication with your back seat driver. :-)
Larry
http://www.larryrussellkellogg.net/links.html
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http://www.ajc.com/news/content/news/science/0104/05marsbar.html
Back-seat drivers on another planet
Instructions for Mars rover come from California
By MIKE TONER
The Atlanta Journal-Constitution
PASADENA, Calif. -- Too many things to do and not enough time to do them.
The six-wheeled robot rover hadn't budged in a day. Tempers were flaring.
Fingers were pointing. And this was only a test. When it comes to driving on
Mars, there are a lot of back-seat drivers.
"We are basically going to have to repeat what we did yesterday," frustrated
geologist Laurence Soderblom told the 50 or so scientists milling around
NASA's Jet Propulsion Laboratory for the final test of the Mars rovers.
"We've got to keep it simple," he admonished. "If we are overly ambitious
with the activity plan, we could be our own worst enemies."
Not everyone agreed.
"I don't buy the idea of dumbing it down," retorted Cornell University
astronomer Jim Bell. "The real problem is the uplink side. We're only asking
them to use predefined sequences from existing software libraries. It's
something they're going to have to get used to."
It hadn't been a good "Sol 21," the simulation of the 21st Martian "day" of
the robot rover Spirit's travels in Gusev Crater.
Today, the rover Spirit is really on Mars, and 90 days of real exploratory
challenges lie ahead. But in late November, on Sol 21 of its final test, the
six-wheeled rover had just one objective: to "scratch and sniff" a rock
called Fromage, grinding away the surface to expose the unweathered surface
for inspection.
A software conflict kept the rover from getting close enough to even touch
the rock with its two-and-a half-foot mechanical arm.
The day was lost. No one was happy about it.
Final exam is at hand
By the end of the exercise, the frustration was palpable -- no less so
because this problem was a deliberate "gremlin," an artificial glitch
designed to test the team's resourcefulness.
Six such operational tests, some of them lasting up to a week, have been
held during the long, six-month journey to Mars.
Now, with the real rover, Spirit, on the surface being readied for its first
drive, and its twin, Opportunity, due to land later this month, the final
exam is at hand. Only this time, the rover is 100 million miles away -- and
years of preparation for the $820 million mission are on the line.
Mars scientists may kid each other about their "Mars driver's licenses," but
they wince at any suggestion that they are "joy-sticking" around the Red
Planet the way children drive remote-controlled monster trucks.
In reality, "driving" Spirit and Opportunity is more like a joint exercise
in diplomacy and computer programming than driving.
The rovers are the most sophisticated machines ever to reach the surface of
Mars, but the machines -- and the men and women responsible for operating
them -- have their limitations.
Each rover is a high-tech monster truck a little over 5 feet long, weighing
384 pounds -- 30 times more than the breadbox-sized Sojourner, the first
rover to make tracks on the surface of Mars in 1997 In 30 days, Sojourner
never strayed more than 100 yards from its landing site; Spirit and
Opportunity could, if scientists want, travel a half-mile or more.
The Mars exploration rovers come with six-wheel drive and a "rocker-bogie"
suspension that enables them to tolerate a tilt of up to 45 degrees without
overturning. Independent steering of the front and rear wheels enables them
to turn on a dime or trundle across a Martian plain at a top speed of about
600 feet an hour.
It's not likely that they'll be doing any speed trials, though. They'll
spend most of their time poking and prodding for hints about an ancient time
when water flowed freely across the surface of the planet. In addition to a
battery of cameras, each carries a microscope, a rock abrasion tool and
three spectrometers that can analyze the mineral and chemical content of
rocks it encounters.
"The rovers are essentially robotic field geologists, and they will be doing
what any good geologist would do in the same situation," says JPL's Matthew
Golombek,who coordinated selection of the two landing sites.
"We land, we look around for interesting things. We go up, swing a hammer
and break off a piece and hold up to look at it through a hand lens."
But with 100 million miles of space between the rover and the scientists who
must explore Mars though its eyes, it's not quite that simple.
For starters, it takes nearly 10 minutes for any command sent from Earth to
reach Mars -- a transmission known as the uplink, and another 10 minutes for
any response, the downlink.
In actual practice, the opportunities are limited to only a few times a day,
because signals must be relayed from JPL's headquarters in Pasadena through
Earth-based antennas in Australia, Spain and California, to two
Mars-orbiting satellites, and finally to the rovers.
Communications are further limited because the solar-powered rovers work
only during the day. They must wait until the sun is in the midmorning
Martian sky before they "wake up."
And even as they roam the rust-red surface of Mars during the day, they must
recharge their batteries to keep the instruments warm during the night, when
temperatures may dip as low as 150 degrees below zero.
Such limitations mean the rover must be able to operate autonomously most of
the time, using each new day's sequence of commands and its own robotic
skills to go where the scientists back home want it to go, and do what they
want done.
"We basically send one set of commands a day and that's it," says Golombek.
"We send them up in the morning and then we're blind until we see what's
happened at the end of the day."
Because the landing site is unknown terrain, scientists will be as cautious
in what they allow the rover to do as parents are the first time their
teenager borrows the car.
The Earthbound "drivers" will chose the day's destination, and may specify a
general route but it's up to the rover to navigate over or around obstacles
and avoid any minor hazards it encounters along the way.
Free within limits
Both the rover and its operators will have three sets of eyes for their
rambles across the Martian landscape -- a high-resolution panoramic camera
that will make 360-degree color pans of the surrounding landscape, a stereo
camera to pick out suitable routes and stitch them together into 3-D images,
and two wide-angle "hazard identification cameras" mounted just above the
rover's two front wheels.
As with any beginning driver, there are limits to what the rover will be
allowed to do. It may not look like Daddy's Lamborghini, but no one intends
to do any wheelies.
"If it encounters a tilt of 30 degrees or more, it will stop and phone home
to let us decide what to do," says Golombek. "And if you find out at the end
of the day on Mars that the day the rover is not where it is supposed to be,
you have all night to work on it."
In a typical day, the rover will operate about five hours, ending in
midafternoon as the sun begins to wane and sending the results of its
Martian workday back to Earth. The rover may sleep the night away, but for
the 150 scientists and engineers in the mission operations area on the
fourth floor of JPL's Building 264, the workday is just beginning.
"We have about three hours from the end of that downlink to make plans for
the next day," says Golombek.
Once the scientists say what they want, the mission director and the
engineers who assemble the rover commands on their computers decide what's
possible.
"Once we have a plan we have about eight hours to build the commands that
we're going to uplink to the rover," says Golombek.
That process may go on until 5 a.m. Mars time, just a few hours before the
sun peeks over the Martian horizon and the rover begins to awaken for
another day.
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Find this article at:
http://www.ajc.com/news/content/news/science/0104/05marsbar.html
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WHAT THE MIND CAN CONCEIVE, AND BELIEVE, IT WILL ACHIEVE - LRK
==============================================================
Thanks for looking up.
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Larry
http://radio.weblogs.com/0119030/
http://kelloggserialreports.blogspot.com/
http://www.larryrussellkellogg.net/
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