NASA announced last week that the Opportunity Mars Exploration Rover has been declared dead after over 14 years of operation. When a global dust storm enshrouded Mars last year, the rover probably became so covered with dust that its solar panels couldn’t produce enough energy to keep the rover going. Once the dust cleared, the rover operators at the Jet Propulsion Laboratory sent signals to try to wake it up, but after a final attempt last week yielded no results, they officially pulled the plug on the mission.
I’ve been expecting this. Given that all attempts to re-establish communications last fall failed, it was only a matter of time. The same thing happened to Spirit in 2010 after it got stuck in a sand pit with its solar panels facing away from the sun during a Martian winter. Once the winter ended, Spirit did not wake up. But even though this announcement was expected, it still makes me feel a bit sad that my old friend is gone. I also feel proud that it exceeded all expectations by lasting 13.5 years longer than designed and traveling over 25 miles across the surface of Mars.
I call it my old friend because that is how it feels to me. I was at JPL during the summer of 2002 when both rovers were being built, and I saw the assembly team putting the parts together in the High Bay clean room in Building 179. I was there as an Educator Facilitator for the NASA Educator Workshops for Mathematics And Science Teachers (NEWMAST) program. My job was to work as a liaison for 25 teachers that had been selected from across the country to attend a two-week all-expenses-paid workshop at JPL. I communicated with them before the workshop to help arrange for their flights. I worked out details with the hotel, rented mini-vans for our daily trips to JPL and elsewhere, and arranged meals, workshop sessions, tours, and guest speakers. I even had the chance to lead a few of the sessions.
I had the privilege of working with Dave Seidel, Art Hammon, and other Education and Public Outreach specialists at JPL. They were with the Mars Exploration team and other missions such as Cassini, Deep Impact, and Stardust. To put the final touches on our plans, I traveled to JPL a week early and then spent several days after the workshop writing final reports and shipping materials back to my home in Utah. I returned later that summer for four days as a NASA/JPL Solar System Educator and received further training. Altogether, I was at JPL for over a month that summer and saw Opportunity and Spirit several times as they were being built.
The Birth of a New Space Probe
Space probes begin as a gleam in the eye of NASA’s Planetary Science Directorate with an Announcement of Opportunity at the Lunar and Planetary Science Conference during the NASA Town Hall Meeting. NASA looks ahead to alignments of the planets and determines if a mission for a particular launch window is part of the their strategic plan, as outlined in the Decadal Survey. In the Town Hall Meeting, the Chief Scientist (currently Dr. Jim Green, whom my students and I met two years ago in Houston) announces the upcoming opportunities and goals – if the probe will be a flyby, an orbiter, a lander, a rover, or a sample return. Different research teams from various universities are in the audience, which is invited to put together proposals for instruments to fly on the bus, or basic vehicle structure, including their cost, dimensions, and energy requirements. NASA looks over the proposals and selects several that have the most scientific merit for further feasibility funding. Those selected build and test a prototype of their instrument and provide detailed reports back to NASA, which then selects the final instruments to fly.
Some don’t make the final cut. I saw a presentation by Wayne Zimmerman of JPL who has created a type of ice drilling torpedo that can heat through planetary ice, collecting and analyzing samples as it goes. It would be ideal for a mission to Europa where a lander would place it onto the thinnest ice. It would drill down until it reached open water (or at least slush) beneath and convert itself into a submersible to explore that ocean. His team received feasibility funding and tested their device on a glacier on an island off the coast of Norway with polar bears migrating through their camp. They went down 50 feet and it worked perfectly. It was sitting on his desk during our tour of JPL, not because it isn’t worthy to go on a mission but because no mission yet has landed on planetary ice. Maybe some day, soon.
Once the final instruments are selected, the probe must be designed, built, tested, and launched. This is the part done at the Jet Propulsion Laboratory and a focus of the workshops I helped to lead for NASA.
The Project Development Tour
On our first full day at JPL, we arranged for the participants to do what Dave Seidel calls the Project Development Tour. For the teachers to learn the phases in designing, building, testing, launching, and monitoring a space probe mission such as the Mars Exploration Rovers, he designed a tour through the JPL labs that paralleled the process a probe goes through. We began in the Badging Office where all visitors have to register, receive a badge, and have an escort take them to their destination.
We took photos out on the quad of our group, then visited the Von Karman Museum to see models and engineering test beds of various rovers, including the test bed for the Galileo probe that was still orbiting Jupiter at that time. We were treated to a presentation and welcome in the Von Karman Auditorium next door, which still contains the mockup of the Voyager space probe that I first saw in 1978 as a high school senior, except that then it was in the middle of the room and is now over on the left side.
We then walked to the Project Design Center and learned how the different subsystems of a probe are designed cooperatively. For example, there has to be a give and take as new requirements/specifications are decided on. Building a larger solar panel, for example, requires more weight and more propellant and a larger tank, so other parts have to be lightened or pared down. It all has to fold up to fit inside the shroud on top of the launch vehicle, then be able to unfold once it reaches and then leaves Earth orbit. It has to be able to survive Mars orbital insertion using aerobraking or drogue chutes then make a soft landing on the surface.
Our next stop was the Micro Devices Lab, where we got to see samples of some of the types of instruments that would be going on Spirit and Opportunity. They had prototype space probes that were the size of shoeboxes with micro thrusters to steer them. They had a micro-etched compact disc with the names of thousands of people (mine and my children’s included) etched on their surfaces and transported to Mars on the rovers (encased in a cover near the calibration target and sundial). They had a scanning tunneling electron microscope (Ooh! Aah!) and a working methanol-air fuel cell system.
This last was important to me because I built my own methanol-air fuel cells as a senior in high school and managed to coax about 70 microamps out of them. This wasn’t enough to electrocute a flea, but my project did win first place in the Southern Utah Science Fair that year and got me a free trip to the International Science and Engineering Fair in Anaheim, CA. One of the days of that fair, we weren’t allowed to be at our booths so the judges could read our data books and our backdrops without us. The fair organizers set up tours, and I chose to visit JPL. It was my first visit, and now here I was helping to lead teachers through the lab and looking at a working fuel cell system. It was fitting.
Once a space probe is designed, prototypes of subsystems are built and extensively tested, such as the airbag system first used on the Pathfinder mission that had to be scaled up for the MERs (since they were bigger and heavier). All of these parts have to be machined and fabricated. We next took the teachers to the Fabrication Shop, which is amazing. For the MERs, the mission was not farmed out to a third party such as Ball Aerospace or Lockheed Martin. All the parts were built in-house in the Fab Shop, and the shop is a machinist’s heaven, with five 5-axis Fodel milling machines and other unique equipment to build the parts of a machine no one has ever built before to do a job never before attempted.
For testing the design, we visited the In-Situ Instruments Lab (ISIL), where the prototype rovers are tested in a large indoor sandbox. Their electronics are thoroughly investigated and ran through their paces to make sure every command is well understood and practiced. We visited the Mars Yard, where a mock up rover bed called FIDO was tested to see how it could handle different types and sizes of rocks. The Mars Exploration Rovers were built with six-wheel drive and a rocker bogey suspension that could handle fairly steep slopes and different types of Martian regolith. Whenever the rovers encountered a challenging terrain, it was simulated in the Mars Yard and tested with the mock up to be certain the rover could handle the challenge, such as driving down into Endurance Crater.
Our next stop was the Vehicle Assembly Building (179) where we walked up to the viewing gallery and watched as the technicians in grounded bunny suits carefully assembled the parts of both rovers. In the front below our gallery window were the backshell and solar panels used for the trip from Earth to Mars. In the back technicians were adding parts to the rovers themselves, with each connection and hookup tested and retested. The room is a Class 5 clean room so that no particles of dust or contaminant can get into the rovers to ruin a circuit. This is cleaner than a hospital operating room, and the entire bay is kept in positive pressure to prevent particles from entering the room. It was thrilling to look down into the High Bay and see the pieces that would travel to Mars the next year and know I was a witness to history.
For the final stop of our full day tour, we hoofed it to the top of JPL, up what is called Cardiac Hill for good reason. At the top of the hill is the Environmental Test Lab, or what everyone commonly calls Shake and Bake, because that’s what they do. Once the space probes are assembled and everything works and fits, they are taken apart and shipped to Shake and Bake for the real testing. They place the parts and subsystems inside an acoustic chamber with large horns that hit the parts with over 150 decibels of sound. Decibels are on a logarithmic scale, so what would be loud to us at 50 decibels would lead to deafness at 100 decibels and irreparable brain damage at 150 db. Yet launching a space probe is so noisy and so shaky that the parts have to be able to withstand these types of vibrations. They place the parts on shaker tables to see if they will fail. They place them in large radiation ovens and pump out all the air and blast them with ultraviolet rays to simulate the conditions of traveling through space. Then they put the parts back together and place the whole rover inside a giant 25-foot vacuum chamber with large arc lamps to simulate the sun.
Only about 2 in 5 parts manage to survive, so the Fab Shop always makes extra – they really built about five probes for each one sent, and keep at least one back as a test bed. When I first visited JPL in 1978 as a high school senior, they had recently sent the Viking missions to Mars and had one of the lander test beds on display in the Von Karman museum, as well as the test bed for Voyager, which is still there but now off to the side instead of in the middle of the auditorium.
Once everything checks out, the final probe is again taken apart and shipped to Cape Canaveral, where it is reassembled inside the shroud at the top of the launch vehicle. I had the privilege of seeing the launch of the Mars 2001 Odyssey orbiter. It launched in 2001 on a Delta II Heavy rocket with five boosters and what a sight that was! And it’s still orbiting Mars.
Communicating with Space Probes
On other days of the workshop we showed the teachers how NASA and JPL communicate with the space probes. This is done by taking the data from the probe (instrument readings, images from cameras, etc.), which is in the form of binary code, and translating it into radio signals using phase modulation. Essentially, a carrier radio signal is modulated by a second signal of the same frequency that is either in phase (adding up or a 1) or out of phase (subtracting out, or a 0). The radio signal travels back to Earth where it is picked up by the large 34 and 70 meter radio dishes of the Deep Space Network.
DSN has three locations around the world so that a probe’s signals can be continuously monitored. These are at Goldstone at Fort Irwin in the Mojave Desert near Barstow, California; near Canberra, Australia; and near Madrid, Spain. On the Saturday of our two-week NEWMAST workshop, we arranged to drive out to Goldstone and take a tour of the Deep Space Network antennas. It was 114° and we tried to fry an egg on the asphalt, but it wasn’t quite hot enough. I will write a later post of a tour that I arranged in 2016 of my students to visit the Goldstone DSN. The photo you see here is of the 70-meter dish taken during our tour there in March 2016.
Once the signals come in to DSN, they are sent directly to JPL from Goldstone via landline where they arrive at the Space Flight Operations Facility (SFOF). We took the teachers to the SFOF as a continuation of the Project Development Tour. I have since taken my own students on a tour of JPL and we got to sit in the visitor gallery overlooking the main operations floor, which looks like mission control and has large monitors showing the data as it comes in to SFOF.
For the third year of the NEWMAST (later NASA Explorer Schools, or NES) program, we took the teachers to the SFOF gallery one evening for a special treat. This was a second year workshop for NES all about robotics and Mars exploration. When visitors use the gallery, EPO personnel can take over the middle screen of the mission control room to make presentations. Dave, Art, and I decided to give the teachers a viewing of the old movie Angry Red Planet on the central screen. The controllers sitting in the SFOF mission control room below had some very puzzled expressions on their faces as they saw the infamous bat rat spider crab appear on their monitor. Don’t ask me what a bat rat spider crab is. Look it up . . . It was one of the most hilarious experiences of my life, doubly enhanced by the setting. Mars is red . . . and it’s angry!
Once the data comes in to JPL, it may need some processing and fixing. There are many ways that data can be corrupted or interfered with on its long journey between the planets, not the least of which is radiation and charged particles streaming out from our sun. The damaged data must be cleaned up then re-translated back into a usable format, such as the pretty pictures of Mars or Saturn that we see in the newspapers and on the Internet. This is done in the Multi-Mission Image Processing Lab, or MMIPL. On one of the days of our workshop, we took the teachers to the MMIPL and had a great presentation on how the navigation cameras on a Mars probe are combined to make a red-blue 3D anaglyph. I questioned Chris Carrara, one of the engineers there, on how to make this work and he gave me instructions which I have used successfully in my own classes.
Having seen Spirit and Opportunity as they were being built and tested, I feel something of an affinity for them. I went over all the diagrams and specifications during our workshops. Yet what makes them my old friends was a project my students participated in a year and a half later. I applied for them to join the inaugural Mars Exploration Student Data Team project, and we were selected as the only non-science team out of 53 groups that year.
My students were media design and 3D modeling students, and we learned how to use the J-Mars software to predict when the Odyssey and Mars Global Surveyor spacecraft would be passing over the MER’s positions. As Spirit and Opportunity approached Mars, we followed their progress carefully. A global dust storm similar to the one this last year kicked up just before the landers arrived, and the scientists were concerned that the dust might interfere with the landings. Since it traps heat, the dust would cause the Martian atmosphere to warm up and expand, changing the timing of when the explosive bolts would need to fire to release the drogue chutes, drop off the backshell and heat shield, and inflate the airbags.
When the MERs landed, I had my students watch them live. Spirit landed first, in Gusev Crater, but it was Opportunity that scored a literal hole in one. It landed in a flat area in Terra Meridiani north of Miyamoto Crater where the Mars Global Surveyor and Mars Odyssey had identified iron hematite. Since the rovers were tasked to “follow the water,” this was an excellent choice because specular hematite can only form in liquid water. Opportunity rolled into a small crater and as soon as they turned on the cameras, the scientists could see sedimentary layers in the crater walls. As Opportunity rolled up for a close-up inspection, it found small rounded iron hematite concretions that were called “blueberries” because that’s what they looked like in color enhanced photos from the MAHLI hand-lens camera on the end of the robotic arm.
As we worked with the science teams, my students also learned how to use 3D altitude data of Mars from the Mars Global Surveyor’s MOLA instrument. It was something of a quest of mine to work out how to get the data into my favorite 3D program, and with the help of such people as Kees Veenenbos I finally figured it out. My students were able to access the UNIX server at JPL that housed all the MER data and download the Tau dust opacity data. We created a 3D animation of the dust storm that hit Mars in December 2003. They used engineering diagrams to build 3D models of Spirit and Opportunity as well as other Mars landers, rovers, and orbiters. They designed and programmed an interactive CD-ROM on the history of Mars exploration. Four of my students (including my son Jordan) traveled to Arizona State University with me to present their project at a student symposium for the MESDT program. We also got to select and acquire an image of Mars from the Mars Odyssey probe through the Mars Student Imaging Program.
Because of their participation in the program, my students were interviewed by local news agencies including two TV stations, two newspapers, and the Associated Press out of Los Angeles (over the telephone). Their 3D models of space probes and the surface of Mars were featured in newspapers. Pretty good for high school students!
Opportunities Roll On
Later that spring I traveled to the NASA Lunar and Planetary Science Conference in Houston to present what my students were doing and how they were using authentic Mars data at a pre-conference workshop. I attended the NASA Town Hall meeting where I saw Dr. Steven Squyres, the Principle Investigator for some of the MER instruments. Later in 2004, as I helped lead other workshops at JPL, we were briefed by John Callas, Project Manager for Opportunity. As we were waiting for Dr. Callas to come in, we could see Dr. Squyres and the other MER planners working out where to send the rovers next. Although we couldn’t hear their discussions (there was a glass partition between us), we could see them display photos from Opportunity of the sand dunes at the bottom of Endurance Crater. Dr. Callas told us later that they were deciding whether or not to send the rover to the sand dunes or if it was time to exit the crater and move on.
Since then, Opportunity has explored progressively larger craters, starting with the small crater they landed in then Endurance, Victoria, and Endeavor Craters. It got stuck for a while in a sand dune but with some coaxing the drivers got it out and rolling again. It has gradually gotten more and more covered with fine Mars dust, although dust devils have cleaned it off from time to time. Its robotic arm went arthritic and it was limping on one of its wheels, but it kept on going even though much more attention was grabbed by first the Phoenix lander and then the Curiosity Rover. Through all of this, over 15 years, I’ve tried to keep up to date on what Opportunity is doing.
Many of the greatest opportunities I’ve had in my life have come about because of the Mars Exploration Rovers. I was at JPL for an educator conference when Curiosity landed on Mars (as I wrote about in previous posts). I won third place in a national lesson plan contest sponsored by Explore Mars, Inc. and received the award from Bill Nye, Director of the Planetary Society. This led to participating in an astrobiology field research study in the Mojave National Preserve with Dr. Chris McKay of NASA Ames Research Center in 2012. I became a MAVEN Educator Ambassador in 2015 with a visit to Goddard Spaceflight Center in Maryland. I’ve branched out with NASA educator opportunities such as the NITARP program, flying on SOFIA as an Airborne Astronomy Ambassador, fulfilling an NSF Research Experience for Teachers program in astrophysics at BYU, and being named first runner up as the National Air Force Association’s Aerospace Teacher of the Year. Opportunity was aptly named for me, at least. It truly feels like I’ve lost an old friend.
Yet the exploration of Mars continues. Curiosity is finally beginning to climb Mt. Sharp in Gale Crater, and the as yet unnamed 2020 Mars Rover is on schedule for launch next year. InSight landed last fall and will provide us with a peak inside Mars for the first time. I hope to see humans land on Mars before I die and the chances are looking better every year.
But for now, goodbye Opportunity.