News & Analysis
Comment
george.leopold
You also have to account for the difference in atmospheric pressure on Mars in ...
t.alex
Suddenly this reminds me of transformer robots with unlimited source of energy ...
Updated: How Mars rover got its 'dream mode'
George Leopold
8/15/2012 9:53 AM EDT
WASHINGTON – The Curiosity rover now gearing up to explore a 96-mile-wide crater on Mars is by far the most complex machine ever to explore the surface of another planet. One big reason is the rover’s avionics, which control everything from its 10 scientific instruments to communications, navigation, cameras and power management – which is where Curiosity’s “dream mode” enters the picture.
Dream mode “is sort of the reptile brain for the rover,” explained Jim Donaldson, the Mars Science Laboratory avionics chief engineer. Implemented in FPGAs, the rover’s dream mode function monitors vital rover systems while its redundant main computers are in “sleep mode” to save power.
Donaldson said the biggest challenge engineers at NASA’s Jet Propulsion Laboratory (JPL) faced in developing rover avionics was development and implementation of the FPGAs that have provided Curiosity with a quantum leap in functionality as it explores the Red Planet. From an engineering standpoint, Donaldson said the biggest challenge was scaling JPL’s FPGA design practices to achieve the higher levels of complexity needed to put a largely autonomous rover inside Gale Crater, which is believed to harbor the conditions needed for microbial life.
JPL and its contractors eventually came up with a system of redundant avionics hardware implemented on about 1.2 million logic gates. That allows the rover’s avionics to interface with all major scientific instruments, sensors and comms links along with the rover’s drive train while also managing power in wake, sleep and dream modes.
Part of the Curiosity's power supply is visible at left. To the right of the power supply is the low-gain antenna and side of the paddle-shaped high-gain antenna for communications directly to Earth. The rim of Gale Crater is the lighter colored band across the horizon. (Source: NASA/JPL-Caltech)
(Click here to see an interactive display of Curiosity's science instruments and other key systems.)
Among NASA's Curiosity avionics contractors are Wind River (VxWorks real-time operating system) and Microsemi Semiconductor (RTAX-S and RTSX-SU FPGAs, high- and low-voltage power supplies, high reliability diodes and signal and power transistors).
As the architect of rover’s avionics, Donaldson has a different view of the so-called “brain transplant” in which NASA engineers essentially switched Curiosity’s main computers from flight mode to surface operations. “I prefer to call it an ‘intellect upgrade’ since [the rover’s] brain remains the same,” Donaldson said during a briefing on Tuesday (Aug. 14).
As mission managers prepare Curiosity for its first drive, they continue to take their time. Curiosity’s mission is being measured in Martian days, or sols. Michael Watkins, the Mars Science Laboratory mission manager, said JPL’s science team won’t try to engage actuators to turn Curiosity’s wheels until Sol 13 next week. The first drive is scheduled for about Sol 15. This will involve little more than a short drive, a turn, then backing up to see what was directly under Curiosity when it landed on Aug. 6.
“We start out crawling and then we walk,” Watkins said.
The Curiosity science team said Friday (Aug. 17) that "we intend to hit the road" in the next several weeks on Curiosity's first long drive to a site called Glenelg. Mission managers described the area as "a natural intersection of three kinds of terrain." The rover could start heading for the foothills of Mount Sharp at the center of Gale Crater by the end of the year, they added.
Thanks to the rover’s avionics, mission managers expect Curiosity to have sweet dreams between its drives around Gale Crater. Quoting Alfred North Whitehead, Donaldson emphasized that Curiosity’s avionics will allow mission managers to explore Mars as never before “by extending the number of important operations which we can perform without thinking of them.”
Related story:
Adam Steltzner, NASA's hipster rocket engineer
|
|
|
|
|
Navigate to related information
Sanjib.Acharya
8/15/2012 11:20 AM EDT
Thanks for sharing more information on the electronics of Curiosity. How is the electronics protected from the harsh environment on Mars. Are these electronic control cards kept inside a climate controlled chamber inside Curiosity? Any information on who the FPGA manufacturer is?
Sign in to Reply
george.leopold
8/15/2012 11:25 AM EDT
Sanjib, we are in touch with JPL to get more details on the FPGA design for Curiosity. Stay tuned.
Meanwhile, we see India is planning a Mars probe:
http://www.rttnews.com/1948501/india-s-prime-minister-announces-mars-probe-mission.aspx?type=in&utm_source=google&utm_campaign=sitemap
Sign in to Reply
Sanjib.Acharya
8/15/2012 11:16 PM EDT
Thanks George! Yeah...India's mission Mars probe was approved this month. Looking forward for more happenings on this mission.
Sign in to Reply
bobdvb
8/15/2012 2:35 PM EDT
I know that Xilinx do a range of RAD-hardened FPGAs which are designed for the rigorous challenge of space travel. Besides FPGAs there are a range of RAD hardened components which are designed to deal with the high levels of exposure.
There is some detail about the computing power of the device on the wikipedia page, the processor is a BAE systems RAD750 with 400MIPS! http://www.baesystems.com/article/BAES_077441/bae-systems-hardware-lands-on-mars-aboard-curiosity-rover
I know that the rover is powered by a 'nuclear battery' which is a plutonium isotope thermopile, this could also be used to heat the rover in the harsh Martian winters, unlike previous rovers this one is designed to operate during winter, which is the reason for the radioactive constant power source.
Sign in to Reply
george.leopold
8/15/2012 3:00 PM EDT
Speaking of heating, JPL reports that temperatures at Gale Crater are greater than their models predicted, and therefore so is Curiosity. Temps will undoubtedly drop when the rover starts climbing the sides of the 18,000-foot central peak, Mount Sharp. The plutonium power source should make continuous operation much easier than the solar-power Opportunity and Spirit rovers.
Sign in to Reply
t.alex
8/19/2012 11:23 AM EDT
Interesting the power source as I thought would be running off solar power like previous models. How does this power source work ? How long can the power last ?
Sign in to Reply
clim
8/19/2012 7:52 PM EDT
The FPGAs are from Actel, now part of Microsemi. Actel FPGAs are low power and flash based. SRAM based FPGAs like Xilinx and Altera are low lower radiation tolerence.
Sign in to Reply
kinnar
8/15/2012 3:22 PM EDT
It is a great piece of Engineering Design that has started successfully walking on a no man's land. Lets see for how much time it is being able to roam over the red planet. It is tough to predict that How much the information obtained from Mars will be useful to mankind but the Dream Mode and the Robot design will surely help the Automobile industries on technical fronts.
Sign in to Reply
dvk
8/16/2012 12:52 AM EDT
Especially the so called "dream mode". I expect this term attracts the marketing gurus associated with general purpose microcontrollers and microprocessors. Then the new ad will say "The lowest power dream mode microcontroller in the world...".
Sign in to Reply
Robotics Developer
8/16/2012 8:26 PM EDT
I think that using a FPGA to provide basic instinct and reactions to save power is a great idea! Not a new one, I have been doing that for years when I was driving home from yet another late night when I had 1.5hr commute times (kidding really!)... I do like the idea of a smaller processor playing baby sitter so the mom/dad can nap..
Sign in to Reply
bobdvb
8/17/2012 3:35 AM EDT
In reality we have been making products with this type of functionality for years. Most set-top boxes we make use a micro-controller for external interfacing and sensing. They perform a power management function, receive remote IR commands and schedule wake-ups. I credit them with a success because the NASA approach is much more expensive but much more powerful, I imagine their FPGA based design is able to monitor the fine data from a wide range of sensors and make decisions, rather than our simple listen and wake logic.
Sign in to Reply
george.leopold
8/17/2012 9:33 AM EDT
No doubt there's a PR angle to Curiosity's "dream mode" since the technology itself isn't really pushing the envelope. What is, of course, is the application: an autonomous vehicle monitoring its own systems from an average distance of about 140 million miles.
Sign in to Reply
Sparky_Watt
8/17/2012 5:49 PM EDT
Why do you refer to the maintenance electronics as "avionics"? I thought that designated airplane instrumentation.
Sign in to Reply
SumeetKumar
8/17/2012 7:12 PM EDT
If the rover has a plutonium based power source, why is it necessary to have a power saving mode? If the energy is not consumed, wouldn't it be dissipated as heat?
Sign in to Reply
Sanjib.Acharya
8/19/2012 12:55 AM EDT
If I have understood it correctly, the same nuclear power source also maintains workable environmental conditions for the instruments on the rover irrespective of harse climatic fluctuations on Mars...continuously. Hence, it is required to avoid unnecessary power wastage in order to maintain power for the mission time (2 years??)...my two cents.
Sign in to Reply
nanov8
8/20/2012 2:54 PM EDT
The power source generates 110W which is not enough to operate the rover at full power continously.
Sign in to Reply
george.leopold
8/20/2012 10:04 AM EDT
Curiosity fired its laser at a fist-sized Martian rock for the first time this past weekend. Curiosity's "ChemCam" fired 30 pulses of laser light at the nearby rock for 10 seconds. ChemCam is designed to catch the resulting light with its telescope, then analyze it with three onboard spectrometers to gather information on the composition of the rock sample. The principal investigator on the experiment reports NASA got "lots of signal."
Sign in to Reply
ReneCardenas
8/20/2012 12:32 PM EDT
This experiments sound awesome, and just wondering out of personal "curiosity" (grin),
what power/energy levels are these laser shots and what is a safe distance to shoot that kind of instrument. I am hoping that there won't be any surprises, ;-)
Sign in to Reply
george.leopold
8/22/2012 2:47 PM EDT
You also have to account for the difference in atmospheric pressure on Mars in determining how the laser operates up there. NASA showed an image in which the plasma resulting from a laser shot on Mars is noticeably larger on Mars compared to Earth.
Sign in to Reply
george.leopold
8/20/2012 4:03 PM EDT
The rock was close by since Curiosity hasn't yet moved. NASA characterized the first laser activation as "target practice" intended to calibrate the instrument. The rock, affectionately named "Coronation" (NASA branding is getting a little out of hand), presented a relatively large, flat side to ChemCam, so scientists reasoned it was a good first target. No work on laser energy levels. We'll try to find out.
Sign in to Reply
EVVJSK
8/20/2012 4:36 PM EDT
I am guessing just running the motors (to move the vehicle) requires a fair amount of energy (due to martian soil resistance). Factor in that a standard PC uses about a 100 Watt Power Supply and the 110Watt Supply suggested by someone above would not allow for running the whole computing system, driving, and firing the laser simultaneously(it wouldn't make for a nifty sci-fi movie) ;-) !
Sign in to Reply
t.alex
8/21/2012 11:53 AM EDT
Suddenly this reminds me of transformer robots with unlimited source of energy :)
Sign in to Reply
george.leopold
8/21/2012 11:48 AM EDT
Next up on Mars:
http://www.spaceref.com/news/viewpr.html?utm_campaign=&utm_medium=srs.gs-twitter&utm_content=api&utm_source=t.co&pid=38219
Sign in to Reply