Mike Deliman

But Not A Drop To Drink...

Congratulations are due to the Mars Phoenix Lander crew.
Not only did their mission get its extension, they found the first part of what they were looking for.

They've confirmed the presence of that illusive substance, so critical to life on Earth: WATER!
Remember, everywhere we find water on Earth, we find something living in it.

Here's the announcement from NASA.  Enjoy!
----

Guy Webster 818-354-6278
                    Jet Propulsion Laboratory,

Pasadena

,

Calif.
                   

guy.webster@jpl.nasa.gov                    

Dwayne Brown 202-358-1726
                    NASA Headquarters,

Washington

               
                    dwayne.c.brown@nasa.gov

                   

Sara Hammond 520-626-1974
                   

University

of

Arizona

,

Tucson
                   

shammond@lpl.arizona.edu                    

RELEASE: 2008-153  July 31, 2008

                   

NASA Spacecraft Confirms Martian Water,

Mission

Extended

                   

TUCSON

,

Ariz.

-- Laboratory tests aboard NASA's Phoenix Mars Lander have identified water in a soil sample. The lander's robotic arm delivered the sample Wednesday to an instrument that identifies vapors produced by the heating of samples.                    

"We have water," said William Boynton of the

University

of

Arizona

, lead scientist for the Thermal and Evolved-Gas Analyzer, or TEGA. "We've seen evidence for this water ice before in observations by the Mars Odyssey orbiter and in disappearing chunks observed by

Phoenix

last month, but this is the first time Martian water has been touched and tasted."

                   

With enticing results so far and the spacecraft in good shape, NASA also announced operational funding for the mission will extend through Sept. 30. The original prime mission of three months ends in late August. The mission extension adds five weeks to the 90 days of the prime mission.

                   

"Phoenix is healthy and the projections for solar power look good, so we want to take full advantage of having this resource in one of the most interesting locations on Mars," said Michael Meyer, chief scientist for the Mars Exploration Program at NASA Headquarters in

Washington

.

                   

The soil sample came from a trench approximately 2 inches deep. When the robotic arm first reached that depth, it hit a hard layer of frozen soil. Two attempts to deliver samples of

                   

icy soil on days when fresh material was exposed were foiled when the samples became stuck inside the scoop. Most of the material in Wednesday's sample had been exposed to the air for two days, letting some of the water in the sample vaporize away and making the soil easier to handle.

                   

"Mars is giving us some surprises," said

Phoenix

principal investigator Peter Smith of the

University

of

Arizona

. "We're excited because surprises are where discoveries come from. One surprise is how the soil is behaving. The ice-rich layers stick to the scoop when poised in the sun above the deck, different from what we expected from all the Mars simulation testing we've done. That has presented challenges for delivering samples, but we're finding ways to work with it and we're gathering lots of information to help us understand this soil."

                   

Since landing on May 25,

Phoenix

has been studying soil with a chemistry lab, TEGA, a microscope, a conductivity probe and cameras. Besides confirming the 2002 finding from orbit of water ice near the surface and deciphering the newly observed stickiness, the science team is trying to determine whether the water ice ever thaws enough to be available for biology and if carbon-containing chemicals and other raw materials for life are present.

                   

The mission is examining the sky as well as the ground. A Canadian instrument is using a laser beam to study dust and clouds overhead.

                   

"It's a 30-watt light bulb giving us a laser show on Mars," said Victoria Hipkin of the Canadian Space Agency.

                   

A full-circle, color panorama of

Phoenix

's surroundings also has been completed by the spacecraft.

                   

"The details and patterns we see in the ground show an ice-dominated terrain as far as the eye can see," said Mark Lemmon of

Texas

A&M

University

, lead scientist for

Phoenix

's Surface Stereo Imager camera. "They help us plan measurements we're making within reach of the robotic arm and interpret those measurements on a wider scale."

                   

The

Phoenix

mission is led by Smith at the

University

of

Arizona

with project management at NASA's Jet Propulsion Laboratory in

Pasadena

,

Calif.

, and development partnership at Lockheed Martin in

Denver

. International contributions come from the Canadian Space Agency; the

University

of

Neuchatel

,

Switzerland

; the universities of

Copenhagen

and Aarhus in

Denmark

; the Max Planck Institute in

Germany

; and the Finnish Meteorological Institute.

                   

For more about

Phoenix

, visit:

                   

 

                   

http://www.nasa.gov/phoenix

                   

 

                   

-end-

Wind River Webinar: Q and A

Hello All,

last week as some of you know I was the featured presenter / presentation for a Webinar.   (you may have problems watching that with firefox...) .  During the course of the webinar, we were asked a number of questions, and we ran out of time...

Here are some of the questions and answers we couldn't get to.

--
Q: What is the biggest advantage of Vxwork over other real-time operation system?
A:  VxWorks is the most well-deployed and well-used commercial realtime OS in the world.  Because of this, the OS is more well-tested than any other commercial RTOS, for this reason I would say the maturity of VxWorks is perhaps it's greatest advantage.
--
Q:have you ever patched the OS or only the application sw?
A: In most cases, only application code is updated in space, though it is possible to patch  or replace even the bootrom code in many of the space robots.
--
Q:Can VXWorks 'replace' itself in case of malfunction?
A: I'm not certain what "replace" means in this context; some of our customers have invented ways to detect bad RAM locations, map around those locations, and load vxWorks to the remaining RAM. 
--
Q:How do you ensure that the RTOS does not crash? Even due to a simple NULL-pointer access? Do you have any built-in Crash Recovery mechanisms in WindRiver for Space systems?
A: While debugging with newer versions of VxWorks it is possible to use the MMU to trap accesses to, for instance, the 0-page, to catch accesses to uninitialized pointers, etc.  Once code is sufficiently  debugged, the MMU may be disabled if desired, or the product may be deployed with the protection enabled.  As far as crash-recovery systems, most of the systems in-flight have created health maintenance and monitoring systems, and event logging systems.  Wind River has learned from this, and our newer OS releases have support for configurable event logs and health monitoring.
--
Q:Do you customize Vx Works for individual customers ?
A: We have services experts available to help with everything from the initial installation, to implementation of the entire product, including modifying vxWorks for a particular project.
--
Q:Which the CPU platforms are apted for VxWorks? How to get more info about VXWorks and its using?
A: VxWorks is available for many PowerPC, MIPS, ARM, Xscale, and other CPU types.  Wind River has offices world wide.  Please check at WWW.Windriver.com for office locations.
--
Q: I know you have a trial version of vxworks, but for a person who want to learn it, it expires quick. do you have a slim version with no expiration?
A: We do not have a "slim" version.
--
Q:  Is there a Webinar that spotlights VxWorks? A Demo?
A:  Demos are available of all of our products, pleas contact your local sales office.
--
Q: how do you update your software on space robots?
A: This is highly dependent on the hardware and hardware capabilities used to implement the robots, so unfortunately our customers must usually invent the right methods.
--
Q: AI and VX Works.. Any efforts to embed supporting AI as a native support on VX Works?
A: Though AI systems and some AI capabilities have been implemented using VxWorks, I am not aware of any efforts to embed more than rudimentary AI functionality along with VxWorks; Stardust, DS1, and the Mars Exploration Rovers are the best examples I can think of that incorporated any degree of AI.  Wind River is not planning on adding any AI capabilities to VxWorks (or Linux) at this time.
--
Q: how do you know when to time out communication to a mars rover when there is so much delay and interference?
A: That is left to the folks who implement the radio protocols used by the Deep Space Network to communicate with all the probes/robots/satellites in deep space.  They are experts with communications in deep space.  I expect sometime in the near future that this will all change with Delay Tolerant Networking and the implementation of the InterPlanetary Internet.
--
Q: Is VxWorks migrating from support of ASIC hardware to FPGA's?
A: VxWorks runs on a variety of platforms including COTS boards, ASIC, and FPGA based designs.
--
Q: All application using embedded controller or PCs?
A: Many manufacturers of COTS computer boards for VME, PCI, or cPCI supply VxWorks BSPs for their boards, and Wind River Systems supports BSPs for several COTS boards directly.  I hope this answers the question.
--
Q: Do you see an increase in the percentage of embedded applications that use some form of Linux vs others like pure VxWorks (i.e. not including VxWorks Linux)?
A: To be clear: VxWorks is NOT Linux, the two are not even remotely related to each-other; vxWorks pre-dates Linux by... years.  Likewise, Linux did not evolve from VxWorks.  They are similar in some respects (Posix, networking support, etc), but they are not even "kissing cousins".  Wind River does have our own versions of Linux available along with VxWorks.
Though I have seen an increased presence of Linux in the embedded arena, and an increased presence in the development and testing phases of even software for space applications, I have not seen Linux promoted to controlling a mission (e.g. the primary flight computer) yet.
--
Q: What problems are unique and interesting to  underwater implementations of VxWorks like those faced by MBARI?
A: I wish I had a contact at MBARI for you to ask!  As far as I know, most issues unique to the situation would be shared by all submersible vehicles, and MBARI has excellent experience in dealing with submersibles and software for underwater applications. Once the mechanical issues of sealing out the environment are taken care of, weather it's space or deep-sea, the rest becomes implementing software to control your devices, debugging, and deployment.
--
Q: [referring to an earlier question] Additional details on my earlier question on RTOS decision making ... The specific application is for an RTOS decision to be made for new instrumentation used in human spaceflight ... that is where do I start?
A: I would imagine you would need to start with the specifications for your deliverables: what kinds of certifications you will need, if any, and what kind of constraints the computer needs to operate under.  For instance, will this be a deep-spacee project requiring rad-hard hardware, or will rad-tolerant hardware suffice?  Will you need FAA or military certification, or none at all?  Wind River is happy to discuss the software packages we have and how they may be applied to your project.
--
Q: which vxworks versions have flown in the past and how customized were they ? (components)
A: VxWorks 5.2, 5.3.1, 5.3.1 MER Edition, 5.5.1, and I think 6.2 have all flown in space.  Other versions have flown in military aircraft, etc.  The most customized component of VxWorks I believe would be the DosFS file system on the MER rovers.  The folks at JPL made some great improvements after the SOL18 issue. 

For the most part, we strive to keep the releases "as close as possible" to the standard releases in order to facilitate technical support and software maintainability.  Newer radiation hardened chips are available that are very similar to commercial parts, like standard PowerPC or Sparc chips, and these newer chips run the same (current) versions of vxWorks as everyone else does.  This allows the customer to use our standard technical support for many issues, making experts more available for all issues.
--
Q: There were flash managment issues on MER and the Polar Lander. Could you explain the issue?
A: The flash management issues on MER "A" Spirit was actually more a RAM management  issue combined with a debug feature, precipitated from a "feature" of the DOS file system.  I am not intimate with any problems experienced on Mars Phoenix Lander, but the last I heard MPL's experts have identified a possible application problem.  Given when I'd heard this, I'd expect they may already have tested and sent-up a fix.
--
Q:Is VxWorks already been ported to RAD750 or Leon3FT ? Do you support academic R&D with easy to access software or anything other than that ? Thanks!
A: Yes - Rad750 BSP is supported by BAE Systems, from Wind River's perspective it's pretty much a "generic" PowerPC 750 and uses standard software and tools.  BSPs are available for VxWorks versions 5.x and 6.x, I believe 6.4 is available and a BSP for 6.6 will be available soon.

Wind River does not directly support VxWorks on Leon, but the manufacturer does have a solution with VxWorks 6.x available (I find this very fascinating and would love to "play" with it sometime).  :)

Wind River does have a University Program, contact your local Wind River sales office for details.
--
Q: How many versions/levels are there of VxWorks, and, how do you choose a version of VxWorks for example a Mars rover?
A: VxWorks has been around for a while, well over 20 years.  When I first saw it, the version was 4.0, and there was one version of vxWorks that ran on top of other companies kernels.  Now there are various versions of VxWorks for specific markets, and platforms available to help tailor VxWorks for specific usage.  I would always recommend using the latest version available for your hardware platform that satisfies the needs of your program.

This was the first webinar I've ever presented.  I hope you enjoyed it as much as I did. 

The Phoenix has landed... but the dust has not cleared

it's another  beautiful day in the Mojave, temps will easily pass the century mark, and there will be another batch of emails with various questions and "trolling" remarks about what exactly is or is not on Mars and how badly crippled it is.

So far, among the letters from the public, I've received claims of:  "it's an Apollo moon-shot fake, like the rovers", there's a short in the robot arm,  the robot arm is broken,  the lander leaked 'rocket fuel', the OS crashed the lander and it's not responding, the lander runs Linux, the lander runs embedded Windows, the lander has a modern computer and uses 128MB of RAM.

Okay.  I'll go through these to see if I can help clear some of the dust.

None of these were faked in studios in Burbank or anywhere else:  Apollo missions, Mars Missions, rover shots from Mars, Phoenix landing on Mars.  As Mom would say:  Go wash your mouth out!

There's no short in the Robotic arm, as far as I know.  What I do know - when Phoenix first landed, the protective covering over the arm did not pull back far enough, and was covering part of the arm.  It was a bit short of retracting all the way, and might have gotten in the way of using the arm.  Over the first night, it finished retracting, and was no problem.  If there is an electrical short in the arm, I have not heard nor seen any news stories about it.

The Robotic Arm is not broken.  The have managed to "cook" the first oven samples, and are doing science; the arm is delivering samples to the oven as desired.

The lander "leaked rocket fuel".  Well, if you watched the landing, after it was securely on the ground, it vented rocket fuel.  Venting is kind of like a leak, except leaks are unintentional.  We did this because the pressurized fuel is no longer needed, and it's better to have the tanks depressurize on our schedule instead of their own.

The OS crashed the lander and it's not responding.  I give you the day-to-day news item list from the Lander, please point me to the story about this:  Phoenix News.

The Lander Runs embedded Windows / Linux / two hamsters on a treadmill.  Well.  No, no, and hamsters might be faster.  I'm sure even Simon Barret has heard enough about it after this article. The lander runs our VxWorks, which is closer to Unix than Linux and runs our proprietary WIND kernel.  Simon even posted a correction in this interview.   I expect we'll both be getting emails about this for a short while.

The Rad6000  computer on-board can be switched-up to a whopping 20 Mhz. 20.  Not 200, not 133.  If they're following earlier design, the OS "knows about" only the bottom 32 MB of Ram, no matter how much is installed; the rest of the ram is used for application specific needs.  The Rad6000 CPU is a RADiation Hardened RS6000 RISC processor, not MIPS, not Intel; it's a predecessor of PowerPC called Power.  By today's standards it's a old war-torn bit of iron, based on what was a high-tech CPU in 1989.
It takes time to take a standard CPU and make it ready for deep space / mega-rad exposure to radiation.

I hope some of the dust is settling..

"Long ago, in a Galaxy far, far away"... perhaps not so far?

Can a planet exist such that you might see two "suns" setting each "night" ?

It appears the answer is: yes.

Bear with me... there's a press from NASA / CalTech / JPL below that's kind of cool, but before sharing that, here's stuff I get asked about all the time.  "Where's the cool stuff to see / read / listen to?  Can you send me some?"  Here's some of those answers for Spitzer Space Telescope.  :-)

If you have time, check out the online version of this article.  It's just that much better with the pictures...

For some really cool windows wallpaper (etc), check out the photos in the Spitzer gallery

Here are Press releases (this is the "Planets Thrive Around Stellar Twins" article, today's release)

And Podcasts are available, too.

Spitzer Space Telescope runs VxWorks 5.3.1 for Rad6000 plus "the SIRTF patch", it's the direct parent of VxWorks 5.3.1 Mars Exploration Rovers Edition.

=====================  and now... the press release:

Whitney Clavin (818) 354-4673
Jet Propulsion Laboratory, Pasadena , Calif.

News Release:  2007-036                                                           March 29, 2007

NASA Telescope Finds Planets Thrive Around Stellar Twins

The double sunset that Luke Skywalker gazed upon in the film "Star Wars" might not be a fantasy.

Astronomers using NASA's Spitzer Space Telescope have observed that planetary systems – dusty disks of asteroids, comets and possibly planets – are at least as abundant in twin-star systems as they are in those, like our own, with only one star.  Since more than half of all stars are twins, or binaries, the finding suggests the universe is packed with planets that have two suns. Sunsets on some of those worlds would resemble the ones on Luke Skywalker's planet, Tatooine, where two fiery balls dip below the horizon one by one.

"There appears to be no bias against having planetary system formation in binary systems," said David Trilling of the University of Arizona, Tucson, lead author of a new paper about the research appearing in the April 1 issue of the Astrophysical Journal. "There could be countless planets out there with two or more suns."

Previously, astronomers knew that planets could form in exceptionally wide binary systems, in which stars are 1,000 times farther apart than the distance between Earth and the sun, or 1,000 astronomical units. Of the approximately 200 planets discovered so far outside our solar system, about 50 orbit one member of a wide stellar duo.

The new Spitzer study focuses on binary stars that are a bit more snug, with separation distances between zero and 500 astronomical units. Until now, not much was known about whether the close proximity of stars like these might affect the growth of planets. Standard planet-hunting techniques generally don't work well with these stars, but, in 2005, a NASA-funded astronomer found evidence for a planet candidate in one such multiple-star system (http://www.jpl.nasa.gov/news/news.cfm?release=2005-115).

Trilling and his colleagues used Spitzer's infrared, heat-seeking eyes to look not for planets, but for dusty disks in double-star systems. These so-called debris disks are made up of asteroid-like bits of leftover rock that never made it into rocky planets. Their presence indicates that the process of building planets has occurred around a star, or stars, possibly resulting in intact, mature planets.

In the most comprehensive survey of its kind, the team looked for disks in 69 binary systems between about 50 and 200 light-years away from Earth. All of the stars are somewhat younger and more massive than our middle-aged sun. The data show that about 40 percent of the systems had disks, which is a bit higher than the frequency for a comparable sample of single stars. This means that planetary systems are at least as common around binary stars as they are around single stars.

In addition, the astronomers were shocked to find that disks were even more frequent (about 60 percent) around the tightest binaries in the study. These coziest of stellar companions are between zero and three astronomical units apart. Spitzer detected disks orbiting both members of the star pairs, rather than just one. Extra-tight star systems like these are where planets, if they are present, would experience Tatooine-like sunsets.

"We were very surprised to find that the tight group had more disks," said Trilling. "This could mean that planet formation favors tight binaries over single stars, but it could also mean tight binaries are just dustier. Future observations should provide a better answer."

The Spitzer data also reveal that not all binary systems are friendly places for planets to form. The telescope detected far fewer disks altogether in intermediately spaced binary systems, between three to 50 astronomical units apart. This implies that stars may have to be either very close to each other, or fairly far apart, for planets to arise.

"For a planet in a binary system, location is everything," said co-author Karl Stapelfeldt of NASA's Jet Propulsion Laboratory in Pasadena , Calif.

"Binary systems were largely ignored before," added Trilling. "They are more difficult to study, but they might be the most common sites for planet formation in our galaxy."

Other authors on the paper include: John Stansberry, George Rieke and Kate Su of the University of Arizona; Richard Gray of the Appalachian State University, Boone, N.C.; Chris Corbally of the Vatican Observatory, Tucson; Geoff Bryden, Andy Boden and Charles Beichman of JPL; and Christine Chen of the National Optical Astronomical Observatory, Tucson.

JPL manages Spitzer for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena . The multiband imaging photometer for Spitzer was built by Ball Aerospace Corporation, Boulder , Colo. ; the University of Arizona ; and Boeing North American, Canoga Park , Calif. Co-author Rieke is the principal investigator.

For more information and graphics, visit www.spitzer.caltech.edu/Media and http://www.nasa.gov/spitzer .   More information about extrasolar planets and NASA's planet-finding program is at http://planetquest.jpl.nasa.gov .

-end-

Test as you... surprise!

There's an old adage in the world of flight - space flight, or otherwise.

"Test as you fly, fly as you test."

It's pretty short and sweet and straight-forward.  Don't fly what you haven't tested.  Test exactly the ways you expect to fly.

In a big, round, wonderful world, it seems "funny" when we hear about problems related to living here.  Problems like aircraft "flipping over" when they crossed the equator because they were adjusting to negative latitude - the coder hadn't thought far enough ahead to think about crossing the equator.

This is the kind of problem that should be found in test, simulation, or in a thorough validation of design and implementation.  The kind of validation that should be done with "other eyes" - not the eyes of the implementing entity.  It's far better to find these kinds of problems before you're in the air, and lives are depending on everything to be Reliable.

That's why I was surprised to read today about problems with the F22, apparently crossing the International Date Line caused the computers to shut-down.

Precipice...

[Editorial by Mike]

5 years hard work
120 minutes great excitement (launch)
7 months boredom (cruise)
6 minutes of sheer terror (EDL)
Ninety  One Thousand+ days of exploration

It all started like this...

January 2001... I received a call from a cohort, someone I hadn't heard from in a long time.

It was, for me, a very happy call.

"Mike, we're putting the team back together.  We're going back to Mars.  Who's available?"

---

Unfortunately from our company it was just me.  The Senior Engineers from the Pathfinder project were both in management now, and not really available for contracted engineering time.  (In a way, I'm an underachiever, I stayed an engineer instead of vectoring into management.)  I would have been honored to work with either or both of them again, last time I learned so much it hurt.  As it is, it's an extreme honor to be requested for a project with any of NASA's shops, and for me - I grew up a stone's throw away from JPL in Pasadena,  the first time was a dream come true, and now the dream is calling me back!

So... back to Mars.  And the rule of the day:  take what we know works, fix things we know are broken, update it as well as possible without introducing huge "deltas", and test the bejeevers out of everything we can.  So, similar drill to the jobs since Pathfinder, only bigger.  In fact, we rolled up a whole new updated release just for this job.

Over the next few years the Rovers evolved from gangly, unlikely looking frame-things into gleaming metallic-and-silicon robots.  Our girls - MER-A and MER-B, were growing up.  Remembering the Dynamic Duo - Pathfinder and Sojourner, these robots had more than both of those combined.  These were serious science machines.  And after so much work on the parts of everyone involved, they were ready to go to Mars.

The various launch ceremonies, gatherings, speeches, and tours were exciting and energizing.  We may all be scientists and engineers, but we're also a great collection of characters.  It was great to see so many co-conspirators all in one place.  We were ready to invade another planet with our work!

Both craft launched well.  Both craft landed well.  The landing ceremonies were more exciting and nervous than the launch.  But in each case, we received the signals telling us everything was okay, and there was much rejoicing.  Opportunity, being the charmed girl she is, landed in the trove that fulfilled the mission's goals right off the bat.

Both Rovers have had their ups-and-downs, their problems and their triumphs.  At this point, our babies are somewhere around 1000 years old, in Rover years.  (With a planned life-span of 90 days, we're over 11 lifetimes on the clock.)  I've followed as much of it as I could, not as much as some, more than many others.  I'm sure other "MER family members" will agree - these are our "robotic children" out there.  Our kids have seen and done a lot of amazing things.  It still boggles the mind: a thousand days... on another planet!

After all this work, and all this overtime operation on the parts of our daughters, and team members, we've come to this:  Opportunity is at Victoria Crater, a crater bigger than most sports stadiums.  This is more than just a deep hole, this is a window into Mars' past.  This is a chance to see more exposed rock face (and geologic history) than we ever imagined we'd have a chance to see.  A wealth of information awaits. 

The Precipice of No Return?

It's much more than a big hole.  It's also a pit Opportunity may not be able to exit from [see Dr. Squyre's entry for September 28th] .  The science guys are looking for safe ways in and out.  If there's a way in, she's going in.  This is an opportunity we can't pass on. She's probably going in even if she can't get back out.  The realization that our baby could get stuck in the hole is a horrible one, what an undignified way to end!  They're tossing her into a pit, for crying out loud!

That was my initial reaction.

After thinking on this for a while, what a fitting and dignified end.  No matter weather she confirms what we've already seen, or shows us - especially if there are surprises - this would be (metaphorically) like dieing in paradise, surrounded by an achievement beyond dreams.  We'll know exactly where she is, and MRO can watch over her throughout his tenure...

Image from Opportunity's panoramic camera:

To Boldly Go...

Seen on SlashDot - did Viking miss signs of life on Mars?

The science facts behind the SlashDot article support that idea.  Remember - in 1976 scientists didn't know a whole lot about Mars; Viking was really the first successfull attempt to put a science observatory on another planet with the idea of operating for more than a few moments.  Viking was designed with what was known about Earth, and some ideas scientists had about Mars.

"Benzenecarboxylates, oxalates, and perhaps acetates " are the telltales this analysis claims the scientists should have been looking for.  But how could they know for sure?  By 2000 (when this article was written), we really hadn't had a chance to study the surface chemistry of Mars in any greater detail. Without having more data on what actually is on Mars, it's hard to make specific claims for what to look for.

With the MER rovers, we used what we learned from previous missions.  Viking taught us to look for oxidized minerals.   Mars Pathfinder and Sojourner found evidence of a warm, wet period.  Mars Global Surveyor gave us a few more clues about where to land and some of the surface chemistry.  With the Mars Exploration Rovers, NASA sent up improved spectrometers and other instruments to determine the composition of the rocks, using the knowledge of what NASA had already found there.

Each of these steps represents the best practices of stepwise refinement - taking what was learned in the previous step, applying it to what we already knew, and moving forward.  In this way we've managed to make a huge amount of progress based on "baby steps", and the results of a few very well planned experiments.  Someday, possibly, these baby steps will be the foundation of a manned mission to Mars.

MS taking some pain out of WinCE?

Microsoft has released WinCE 6.0 - this time as a "shared source" release, with various enhancements.  Some of the big claims-to-fame:  It's the "first commercial hard real-time OS released as a shared-source product".

I'm not sure exactly what this means.  Perhaps they're using their source licensing model - "shared sourcing" - as a qualifier?  Since it's the only RTOS made by Microsoft with sources shared through their license, that makes the "shared" part true.  From that perspective, there are licensing options for source code from most proprietary OS companies, you just can't post it all to the web for anyone to download.

As far as "open" goes, MS is capitalizing on the fear of the GPL - no-one has challenged it far enough yet to know if using a GPL OS would make it so you have to release your *applications* under a GPL umbrella. But ignoring this bit - there are a number of realtime or at least nearly-deterministic kernels available via GPL and Open Source communities (a quick online search yields over a thousand pages with the exact phrase "Open Source RTOS").

Determinism: putting the "Hard" in Real-time.

There are hundreds of open-source OS's - some are even deterministic enough to be "hard realtime".  RealTime is basically "fast enough to keep up" - but hard realtime means "measurably deterministic" - not just fast enough to keep up, but measurably and predictably able to keep up with a given load. WinCE 6 makes the claim that it's hard realtime  But... is it really a hard-realtime system?  Just claiming you're "RealTime" isn't enough - as This Stanford Comparison  shows, some systems claiming to be "Real Time" don't quite show determinism, especially when running as a "loaded" system.  Part of determinism is being able to give "deterministic" execution - that is, you can be guaranteed that the OS itself won't take longer than a given window of time to react to the world.  Execution times for critical system activities that vary over an order of magnitude is not a shining example of "determinism" (see page 4!).

I don't know if you've done any research into this part of the topic - but if you do, you'll notice that many comparisons for determinism messier things like context-switch time and Interrupt Latency (how long it takes the OS to handle an interrupt or change contexts, usually measured under idle and highly-loaded conditions).  I've never seen such a document for WinCE - and most of what I've seen was either from MS themselves or from companies hired by MS to run their tests.  Though their method is scientific, it requires specific hardware and tools, and their graphs don't give you the complete story for context switching or interrupt latency.  Since the method isn't shown against any other RTOS, there's no comparison possible.

WinCE 6 has extensive use of virtual memory spaces, including supporting up to 32,000 processes each with a 2GB addressable virtual address space.  This requires at least changing memory maps, and possibly "swapping" chunks of text and data  between RAM and some fixed storage.  The act of swapping - pushing data to/from physical media - induces indeterminism.

Other than this - there are some interesting developments.

It's being bundled with Visual Studio with an integrated Platform Builder plug-in.  Microsoft says ""Under one roof, you have the entire development chain from device to application".  Eventually it might have some sort of data visualization tools, perhaps some kind of system event display, maybe even.. hardware-assisted debug... could it be that Microsoft may be joining the DSO trend?

One Thousand Days

This afternoon, Spirit Rover will start it's 999th Sol (Martian Day) on Mars.  Tomorrow will be Sol 1K.

Next month, on the 14th/15th of November, Opportunity's calendar will hit the same milestone.  A Thousand Days on-planet.

Congratulations to all the teams who crafted, constructed, controlled, and cajoled the rovers from conception to the current-day.  Well Done!

Web Sites:MER Rovers , NASA

Mars Rovers: Extended Mission

Hello All,

every once in a while you get to hear something about a project you've worked on.  Sometimes it's good, sometimes it's not so good.  Sometimes it's good enough to give you energy to work through the 20th hour...

I'm extremely proud and happy to share the attached news.  Our kids on Mars have been given another year of operations funding.  :)

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Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.

Erica Hupp/Dwayne Brown   202-358-1237/1726
NASA Headquarters, Washington

NEWS RELEASE: 2006-115    September 25, 2006

NASA Mars Spacecraft Gear Up for Extra Work

NASA's Mars robotic missions are performing so well, they are being prepared for additional overtime work.

The team operating the twin Mars Exploration Rovers, Spirit and Opportunity, since January 2004, won approval for an additional year of exploration. NASA funded the extensions on recommendations from an outside panel of scientists. NASA also is adding two more years of operations for Mars Global Surveyor, which has been orbiting Mars since 1997, and the Mars Odyssey orbiter, at the red planet since 2001.

These mission extensions will begin Oct. 1, 2006. The spacecraft beginning extended missions have already completed a successful prime mission plus years of additional service. The extensions occur when NASA's newest Mars spacecraft, named the Mars Reconnaissance Orbiter, is about to begin its main science phase.

"Each of these missions increases the value of the others and of the Mars Reconnaissance Orbiter," said Doug McCuistion, director of NASA's Mars Exploration Program, NASA Headquarters, Washington. "By extending these missions, we gain very cost-effective additional benefits from the investments in developing them and getting them to Mars."

Each orbiter has a different set of instruments, and the spacecraft complement each other in helping scientists understand Mars. Also, observations by the rovers on the ground validate interpretation of information from the orbiters. Observations by the orbiters allow extrapolation from what the rovers find in small areas. The orbiters support current and future surface missions with landing-site assessments and communication relays.

Both rovers are still healthy, more than 31 months into what was originally planned as a three-month exploration of their landing areas. Provided they remain operable, their fourth mission extension will take them into Martian spring and summer, increasing their solar-energy supply and daily capabilities. Spirit has been studying its surroundings from a stationary, sun-facing tilt for several months. "As we get into the Martian spring, Spirit will resume exploring the inner basin of the 'Columbia Hills,'" said Dr. Bruce Banerdt, rover project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Opportunity will spend the extension at "Victoria Crater."

Each Martian year lasts nearly two Earth years. The longevity of Mars Global Surveyor and Mars Odyssey has allowed researchers to watch how Mars changes not just from season to season, but from year to year. Mars Global Surveyor has observed shrinking of the south polar carbon-dioxide ice cap from one summer to the next.  "This extension will take us through our fifth annual cycle of Martian summers and winters," said Thomas Thorpe of JPL, project manager for Mars Global Surveyor.

"With the additional years of observations, we are able to monitor the Martian climate, not just the weather. There is a hypothesis that Mars' climate is changing, perhaps rapidly. The combination of instruments from different orbiters strengthens our ability to study that possibility. With Odyssey, for example, we can monitor the mass of carbon-dioxide frost in winter to help understand the changes that Global Surveyor is seeing in the summers," said JPL's Dr. Jeffrey Plaut, project scientist for Mars Odyssey.

The Odyssey flight team at JPL and at Lockheed Martin Space Systems, Denver, plans to teach the spacecraft some new tricks during the mission extension. New software will enable the spacecraft to make choices about which images are high priority. Also, the team will begin pointing Odyssey slightly off the straight-down view it has flown so far. This will enable imaging of polar areas it never flies directly over. Odyssey also will continue serving as the primary communications relay for the rovers Spirit and Opportunity.

NASA also has extended the U.S. participation in the European Space Agency's Mars Express mission.  That orbiter reached Mars in 2003 and is in an extended mission.

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Global Surveyor, Mars Odyssey and Mars Exploration Rover projects for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the Global Surveyor and Odyssey projects and built those spacecraft.

For additional information about NASA Mars missions, visit:
http://www.nasa.gov/mission_pages/mars/main .

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