This is the first part of a three-part blog about the end of the Cassini mission to Saturn, and my small part as an observer at the Jet Propulsion Laboratory during mid-September 2017.
Everyone remembers their first glimpse of Saturn through a telescope. It seems unbelievable that you could see a planet with rings—but there it is!
I gazed at Saturn a few weeks ago with my new 90mm spotting scope, and I attempted to capture my first image of a planet that evening. I shot several minutes of video through the scope and then used image stacking software to make a composite of the hundred or so best frames of video. To my surprise, the image came out pretty well. The image in the video is much larger than Saturn appeared through the eyepiece. You can just make out some of Saturn’s atmospheric bands and maybe a hint of the Cassini division between the A ring and B ring…or am I imagining I see that detail because I know what’s there?
Even more incredible to me as I peered through the eyepiece at this planet nearly one billion miles away was to realize that there was a robotic sentinel on duty—the Cassini orbiter, which had been exploring Saturn’s neighborhood for thirteen years. Its fuel spent, Cassini’s mission was coming to an end on September 15, 2017. The probe would make a fiery dive into Saturn’s atmosphere at about 5 a.m. California time that day.
And I would have a ringside seat for the final moments.
The Setup
My good friend and neighbor Stephen van Vuuren has been making a movie about exploring the universe, with Saturn as the centerpiece. The painstaking work of selecting and editing the seven million photographs—there is no CGI in the movie—has taken twelve years, nearly as long as Cassini has been in orbit. In Saturn’s Rings will be coming to theaters starting May 4, 2018. Stephen has many enthusiastic supporters at the Jet Propulsion Laboratory (where Cassini was designed, built, and controlled). He was encouraged to apply for media credentials to cover Cassini’s “Grand Finale.” He asked me to be his onsite producer—lugging gear, running sound, and scheduling and conducting interviews. Of course I gladly agreed!
Our departure from North Carolina on September 12 was nearly impacted by the remnants of Hurricane Irma. Irma was by then a tropical depression and had veered to the west of the track that had initially had it headed straight toward us. We left our homes at 4 a.m. for a drive through gusty winds and rain to get to Raleigh-Durham Airport. Much to our relief, the flights to Chicago and then on to Los Angeles were on time. Even the notorious LA traffic didn’t stand between us and getting to the Arcadia area.
That evening, we met up with Mike Malaska (at left in photo), who had first introduced me to Stephen on September 7, 2011. Mike is now a planetary scientist at JPL, studying Saturn’s largest moon, Titan. On the way to dinner, Mike stopped at an overlook and took a selfie of the three of us with JPL in the background. Mike noted on his Facebook post of the photo that each of us were where we were now because of the Cassini mission. Dinner that evening was kind of a blur, because by that time Stephen and I had been up for more than 20 hours. However, we were conscious enough to remember that Mike told us he had secured invitations for us to attend the Cassini science team party on Friday evening at the Pasadena home of Andy Ingersoll, the legendary CalTech professor of planetary science.
Wednesday, September 13
We arrived at JPL at 9 a.m. to find the visitor parking lot already full to capacity. Obviously JPL was the place to be this week. We picked up our press credentials and then went over to the newsroom adjacent to the von Kármán Auditorium to request interviews to be set up the next day. We then attended the end of mission preview press briefing with Jim Green (NASA director of planetary science), Earl Maize (Cassini project manager), Linda Spilker (Cassini project scientist), and Hunter Waite (lead scientist for Cassini’s mass spectrometer instrument).
From there, we went on a brief tour of JPL, stopping for a few minutes in the Mission Control Center and visiting the Mars Insight Lander testbed and the clean room where Cassini was assembled. Although the assembly jigs were just being put into place, it was incredible to see how large the heatshield for the Mars 2020 Rover will be.
Back at the news office, we learned that we had three interviews scheduled for the next day. We also recognized and introduced ourselves to Emily Lakdawalla from the Planetary Society. She also agreed to be interviewed on Thursday.
Thursday, September 14
We left our hotel room for JPL with the realization that Cassini’s last stand would occur overnight TONIGHT. Somehow we felt like we had an extra day. Now, still jet-lagged, it appeared that we would be up for the next 24 hours. When we checked in at JPL, we double-checked the schedule and also confirmed with the newsroom staff that the media area would be closed between 4 pm this afternoon and 3 am the next morning. Whew. We’d be able to get at least a few hours of sleep.
Our goals for the day’s interviews were to discuss with Cassini team members their thoughts about the mission and how it affected them, the mission’s place in history, and how the amateur community can assist with bringing images from spacecraft to the broader public. We scored a great position in the auditorium in front of the one-half scale Cassini model. Most of the mainstream media seemed to be out and about on the JPL campus that day. Once Jim Green finished his welcome briefing to the NASA Social participants, we essentially had the auditorium to ourselves most of the rest of the day.
Prior to the start of our interview, I reflected for a moment on the size of the Voyager engineering model in the auditorium. This was a BIG spaceship—and its instrument package was relatively small compared to Cassini. The high gain antenna is huge. To think that its 22-Watt communications beam back to Earth has been reduced in strength to 0.1 billion-billionth of a Watt by the time it reaches us… It’s unfathomable what these folks can pull out of this technology.
Our first interview was with Trina Ray, who had been on the Cassini project since before the spacecraft launched. Her most recent assignment was to coordinate all of the science requirements for the final 22 orbits, trying to solve for the best way in which all of the science teams could get their priorities met while protecting the spacecraft. As a Solar System Ambassador, I had participated in one of her recent presentations, and I enjoyed meeting her in person. She told us that she is moving on to the Europa Clipper mission (as is, apparently, just about everyone else we met at JPL).
Next we had a surprise—Linda Spilker requested an interview with us! She had heard (via Mike, of course) about In Saturn’s Rings, and she was eager to learn more about Stephen’s project and to share her reflections with us. We talked with her at length about NASA’s decision to share imagery with the amateur community in real time, and how the work of amateur image processors has supplemented the science of the official project team. She said that even though amateurs had scooped the project team on one important discovery. (I assume that she meant when the amateurs in unmannedspaceflight.com—myself included—were the first to analyze publicly what appeared to be outgassing on Enceladus, on February 19, 2005.)
Linda spoke about the beauty and complexities of the ring system, the dance of the moonlets, the propellers, the icy pileups along the edge of the B ring and their shadows at equinox, and the enigmatic “Peggy” that appears to be a moonlet trying to form at the edge of the A ring. We felt honored that such a senior and in-demand person would take half an hour to share her reflections with us.
We next spoke with Emily Lakdawalla, who has been one of the champions of amateur image processing since the early days of NASA’s presence on the Web. She talked about how people can start processing images on their own, using NASA’s publicly-available data. She saw one huge advantage of amateur image processing is that we are not bound by having to make the images 100% scientifically pure. We can boost color or remove blemishes to improve the visual appeal—so long as we let the audience know that we have done so. NASA is constrained to keep its publicly-released image products as scientifically accurate as possible, which sometimes makes them not as beautiful as the subject might deserve.
We took a snack break in the courtyard, and just for curiosity I checked out some of the online postings for jobs at JPL. They included such great position titles as:
- Dark Energy and Dark Matter Scientist
- Mechatronics Engineer II
- Spacecraft Design Engineer IV
- Europa Software Architect IV
- Planetary Security Architect V
- Mars Robotic Sampling Hardware Engineer
In the small-world department, I saw seated at a table across the courtyard a young woman who I recognized from Spacefest II in 2009. At the time we met, she was a grad student. Now, she sends commands to the Opportunity rover on Mars. Wow!
If JPL isn’t the coolest place to work on Planet Earth, I don’t know what is.
After lunch, we were introduced to Powtawche Valerino, who was navigation team member. When she met us, she asked if she could also invite her team lead, Kevin Criddle, with whom Stephen had corresponded previously. Of course we agreed, and Kevin soon joined us. It was fascinating to hear the two of them talk about how Cassini had used Titan as its primary “propulsion system” for navigating its way through the Saturn system over the past 13 years. Cassini used more than half of its propellant to get into orbit. Gravitational assists from Titan flybys were essential in steering Cassini toward other moons and also to change the inclination of Cassini’s orbit relative to the plane of Saturn’s equator. Flybys also enabled scientists to study Titan’s internal structure as precisely as if Cassini had been in orbit around that moon.
We left JPL at 4:00 and headed back to the hotel for a quick dinner and then to try to get some sleep. We would be getting up at 2 a.m. for Cassini’s final dive into Saturn’s atmosphere!