In Part One of Starhustling with SOFIA: A 747SP Star is Reborn, we talked about the NASA program and its unique Boeing 747SP, originally built to carry passengers on ultra-long haul routes but is now used to carry the world’s only flying infrared astronomy laboratory and flying infra-red telescope.
The Flying Observatory
As promised, our time space continuum ricochets us back to the all important science. SOFIA’s telescope was designed and built for the DLR by a consortium of Germany’s leading aerospace companies – Kayser-Threde GmbH and MAN Technologie AG. It has a full altitude range of +20 to +60 degrees above the horizon. Even in moderate chop, the telescope stays stable due to its spherical bearing, shock absorbers and gyroscopes.
SOFIA’s signature visual cue is the bulge at the aft of the fuselage with a 172-inch wide by 226-inch tall door behind the pressure bulkhead engineered into the port side. This URD door opens in darkness once the aircraft reaches FL350 revealing the reflective telescope in an non-pressurized part of the aircraft that has an effective diameter of 2.5 meters (100”).
The door remains closed during daylight in the air, not just because observation would be impossible, but because direct sunlight would destroy its optics and create a fire hazard. For these reasons, SOFIA is often called the “Vampire Jet” as it only flies at night, except for a ferry or an engineering flight.
Should the door jam in the open position, care must be taken to ensure that the airplane diverts at night. Any diversion runway must not be facing the direct sun. As SOFIA pilot Troy Asher said, “I have a picture wearing sunglasses because it was one of the few times we flew during the daytime.”
SOFIA also avoids flying into any convective activity or clouds, as water vapor disables the science gathering. Turbulence can also cause the telescope to de-lock from its target.
The reflective telescope resides aft of the relocated forward pressurized bulkhead on the left side of the aircraft, but why? “All airplane observatories have telescopes on left side. It’s for when you fly west into the winds and you are flying 3/4 the speed of sound, which is 10% of earth’s rotation speed. You can slow down the rising and setting of objects when flying west.
The telescope is more susceptible to turbulence in the rear. It would be smoother in the front, but the cost was more prohibitive and it would have limited pilot access to rest of aircraft. And if the telescope cavity opening was right above the wing, it would introduce turbulence over the left of the wing so it was ruled out,” pointed out Flight Planner Allan W. Meyer. Meyer has been participating in airborne astronomy since 1975, starting back on the Kuiper Airborne Observatory (KAO).
The rear assembly of the telescope is visible to the cabin, and there’s a perfectly reasonable explanation for that. SOFIA is designed to perform many types of missions and these require separate and distinct instruments to be attached to the telescope. It’s hardly a one size fits all proposition.
Some of SOFIA’s instruments have been funded by DLR and manufactured in Germany. As a generalization, they observe infrared energy – one part of the electromagnetic spectrum, but they have many different functions, rendering SOFIA a true multi-use observatory.
The instruments consist of cameras, spectrometers, and photometers. They operate at different infrared wavelengths. Some are dedicated to studying specific astronomical science phenomena. Other instruments serve a more general role but are capable of acquiring data simultaneously with another more specialized instrument.
SOFIA currently has eight instruments in its arsenal. The six infrared instrument suite includes three spectrometers (EXES, FIFI-LS, upgraded upGREAT), three IR camera’s (Flitecam, Forecast, and new second generation for 2016 HAWC+). These are joined by two Optical Instruments: Focal Plane Imager (FPI+) and 1 photometer (HIPO).
Each science instrument undertakes 4-10 flights in its series. The instruments can be deployed on multiple series per year depending on the science, but all do fly each year. They take roughly a day to physically switch in and out of the telescope.
Each instrument possesses its own research team supporting its mission. Though the flight crew, mission directors, and telescope operators operate across all flights, the instrument operators and scientists usually only fly with their assigned instrument.
Palmdale, we have a Problem…
SOFIA’s science operations center and the program office are based at NASA Ames Research Center at Moffett Field, California; Ames manages SOFIA’s operations in cooperation with the Universities Space Research Association (USRA; Columbia, Md.) and the German SOFIA Institute (DSI; University of Stuttgart).
The SOFIA 747SP is based in a former B-1 Bomber plant at NASA’s Armstrong Flight Research Center, Building 703, in Palmdale, California – at Air Force Plant 42, Site 9. NASA’s DC-8, Gulfstream III, and other aircraft reside alongside in the cavernous space. During the Southern Hemisphere Winter / Northern Hemisphere Summer, the SOFIA 747 platform is based at Christchurch, New Zealand.
It was from Palmdale that Airways was invited to fly a Cycle 4 mission in February 2016, a year-long observing period scheduled for 106 flights through the end of January 2017.
Cycle 4 has ambitious goals for its more than 550 hours of observations,” said Pamela Marcum, NASA’s SOFIA Project Scientist. “We’ll be studying objects spanning the full gamut of astronomical topics including planets, moons, asteroids and comets in our solar system; star and planet formation; extra-solar planets and the evolution of planetary systems; the interstellar medium and interstellar chemistry; the nucleus of the Milky Way galaxy, and nearby normal and active galaxies.”
Later in Cycle 4, the SOFIA observatory was scheduled to deploy to the Southern Hemisphere for seven weeks in June and July 2016, with 24 flights planned from Christchurch, New Zealand. SOFIA scientists will have had the opportunity to observe areas of interest that are not visible or are difficult to observe from the Northern Hemisphere, such as the Galactic Center and other parts of the Milky Way. This is further support for the power of the airborne platform.
The day prior to our mission consisted of egress training in Palmdale, which is valid for one year. As SOFIA Public Affairs Officer Nicholas Veronico noted, “There is nothing standard about this 747SP anymore and much has changed since its days as a Pan Am Clipper. All passengers (mission participants) need to carry their own portable breathing equipment and fire mask and know how to use and deploy the emergency escape slides. There is no escape path lighting in the airplane.”
The vintage emergency escape film depicting a pilot escaping from the top door of the cockpit and repelling down the fuselage was a bit harrowing and looked like a scene out of a 1970s disaster film.
He did advise that beside safety, one of the most important duties we were assigned to was to provide our own catering and sealed thermoses as only coffee and water are offered onboard. “And it’s not a bad idea to bring chocolate, donuts, or M&Ms onboard to share with the crew because after all, ‘M&Ms make friends.’”
In preparation for our all night mission the following night, we were asked to sleep as late as possible the following morning and nap to be as alert as possible for the all night flight.
The moment(s) we had all been waiting for finally arrived, or did it? Unfortunately, jet lag and excitement conspired against us, and we were unable to sleep in. Still, the adrenaline, abetted by heavily caffeinated coffee, had kicked in and we were ready.
On the flight line, preparations for the all-night flight were well underway. The 747SP would be topped off with 250,000 pounds of fuel for the ten-hour overnight flight. The planned target landing fuel is around 20,000 pounds. Most missions are planned to spend 6 hours at or above FL370, climbing up to FL450 when the mission dictates.
As SOFIA pilot Manny Antimisiaris explained, the door for the telescope opens thirty minutes after departure, and is closed at FL350, thirty minutes prior to landing. Descent rates are planned at no more than 2,000 feet per minute through 10,000 feet to prevent any condensation damage to the telescope.
While waiting for our mission briefing to begin, we were given the opportunity to do a deep dive with the accomplished flight crew on SOFIA’s flight operations.
There are 12 pilots in the SOFIA program, and all are dual qualified on at least one other NASA airplane. These include the Gulfstream G-III, the DC-8, or the U-2. The 747SP pilots train on a 747 Classic simulator owned by NASA that is located in Denver, Colorado. They are required to have a landing every 45 days.
Flights are optimally planned for 10 hours to consider rest and duty requirements and operate under Part 91 with an un-augmented standard three-person crew. This allows enough crews to perform three flights per week. Flying is typically on Monday, Wednesday, and Friday or Tuesday and Thursday. Actual scheduled flying more than 12 hours is the limit with 14 hours, the duty limit. The SP can perform 14-16 hours of mission, but the sweet spot is 10 hours.
Lufthansa Technik in Hamburg undertakes all heavy D checks in every seven years. The airframe has approximately 11,000 cycles and 77,000 hours on it, making it very young in those terms if not for actual age. The SOFIA mission program places approximately 600 cycles and 1,000 hours on the airplane per year. SOFIA boasts a 93% dispatch rate, but it’s the 7% scrub factor that would come back to haunt us later.
At 17:39 on February 25, the mission brief began. The atmosphere was light but purposeful. It felt almost like a scene from The Right Stuff. The briefing consisted of the maintenance status of the airplane and telescope, as well as the weather and science observation targets. There was some convective weather over the Pacific Ocean with tops up to 35,000 feet, but that was dissipating. One warning area on departure (W291) was to be avoided. There were also recognition patches distributed to veteran crew and scientists.
After boarding, it was discovered that there was an issue in transferring power from the ground power unit to the APU (auxiliary power unit). Initially, there would be a one-hour delay. SOFIA had to be completely powered down and everyone onboard except mechanics was shuttled off the aircraft. Back in the briefing room, discussions and flight planning adjustments commenced where initial legs would be dropped.
A two-hour window deadline was put in place, after which the entire night’s mission would be scrubbed. The longer delay caused issues because the plane won’t have fuel offloaded in time, which would delay the climb and affect the execution of science. Because the targets have to be reached on-time, the aircraft can’t extend the flight plan beyond sunrise.
At 21:45, with the problem not repaired, the decision was made to abort the mission and everyone was sent back to their homes or hotels. It was unclear whether SOFIA would be repaired and to shoot stars the next day.
We, of course were disappointed, but the scientists who had their long-planned experiments postponed or even cancelled for scientific reasons were the ones who really had cause to be distraught. Good attitudes, a sense of humor, and overall professionalism belied everyone’s obvious disappointment.
All Systems Go: Pre-Flight Briefing and Exploring SOFIA
After a somewhat restless night wondering, “Will she or won’t she?”, we were notified the following morning that SOFIA would indeed be flying later that Friday Night – Thank God for Friday! The faulty electrical control unit was replaced and at least for the moment, all systems were a go.
In a sense of déjà vu with some new crew swapped in, the mission team gathered again around 17:30 on Friday February 26th for the briefing.
Once again things kicked off with the roll call of crew and scientists by our Mission Director Randy Grashius. Before we got down to business, he was awarded his 100th Flight patch. Grashius is one of only two people to have flown SOFIA that many times. As with most Mission Directors, he flies 4 to 8 missions per month.
The Mission Director’s paramount responsibilities include safety and gathering of scientific data. “We coordinate with scientists if there are issues with data. We are the ultimate deciders over anything science related or telescope related,” says Grashius.
Our crew of twenty-five souls included twenty-one on the science contingent, including 2 members of the press. Our flight deck compliment of four pilots was Captain Troy Asher, Co-pilot Ace Beall, Flight Engineer Tim Sandon, and Navigator Brian Elit. In spite of the long flight and in contrast to similar duration long-haul flights, there are no relief pilots, and aside from quick trips to the lavatory and through the cabin, the pilots are on duty the entire flight.
For our mission, OC4-B Flight 3, we would be studying ten waypoints for 10 targets, including Mars and Titan (moon of Jupiter). Our instrument of choice was The Far Infrared Field-Imaging Line Spectrometer (FIFI-LS).
Our flight plan was scheduled with legs to navigate the western two-thirds of the continental U.S.: Palmdale, California northeast to Nevada, the Utah border, Washington State, back down to northwest Nevada, traversing the Montana/South Dakota border, across the Northern Midwest Plains to the Southern Indiana, Illinois, Kentucky region; then a sharp due west track to Southwest Missouri, intercepting Mars en route over Missouri, intercepting the Titan target over Northeast New Mexico, then over Needles, CA, before returning to Palmdale.
For tracking purposes, our flight was numbered 281. Airborne time was set for 9 hour, 47 minutes.
After much anticipation and trepidation, our rendezvous with the heavens was finally at hand. We went out to the flight line to discover the earth-born star of the show, the SOFIA SP, dramatically illuminated at dusk on the Palmdale flight line. I say “flight line,” with a bit of irony since no other airplanes are visible anywhere around.
In fact, photography isn’t allowed on the airfield. Though the scientists and crew were all business, us media types swarmed the pristine bird capturing every angle under the watchful eye of the NASA team. We ascended the steep air stairs, which was itself a throwback as anticipation built at every step.
Upon entering door R1, we encountered a cabin that was an almost overwhelming dichotomy of a long since passed 1970s long-haul airliner, futuristic NASA mission control, and the International Space station. We made our way up to the nose section of SOFIA to discover a most unusual front cabin.
On the right side are 7 rows of 2 Lufthansa Business Class from the turn of the Millennium seats designed with the famous JU-52 corrugated metal motif. Directly across the aisle are enclosed racks of communications systems equipment, including fifteen terabyte hard drives where all the data collected during the mission is stored. Due to the size of the files, there is no in-flight telemetry of the science data, so it is all collected and stored redundantly in flight before it is physically transferred to Ames.
No tour of a 747 is complete without a visit to the penthouse. We wound our way up the 1970s vintage spiral 747 staircase to discover the most intimate of intimate upper decks: A shortened upper cabin consisting of 8 more of the Lufthansa Business class seats in 2 rows of 4. These are generally unoccupied during flight, except for an occasional flight observer.
In lieu of a galley, at the aft of the upper deck’s shortened cabin, is a small door that leads to a storage and electronics compartment where celebrities and other VIP’s have signed the back wall of the partition. Due to the busy pre-flight activity, we are encouraged to visit the flight deck during flight- a real treat, as the door is open and accessible during the entire mission. This would become our second home.
Continuing on our exploration to the mid-cabin, we find two freestanding lavatories in exact 1970s condition right down to the Pan Am blue trim. Abutting them is our open plan galley, or more accurately a microwave oven, refrigerator, and a table overflowing with high energy snacks, jerky, and an avalanche of junk food. This space army definitely travels on its stomach.
Directly to the left of the R1 door is the meeting and planning table, which itself has four 1990’s era United Economy Class seats. It’s not VIP but is conducive for planning and gathering. There are numerous rudimentary AC power outlets and USB ports scattered about, but there’s no inflight connectivity on the network for anyone but the science team.
SOFIA’s mid-cabin is where the aircraft dons the appearance of NASA mission control, with consoles, computers, and monitors displaying esoteric data, alien user interfaces, and celestial images galore. It’s all business here as well. I spotted no one playing Mind Craft or surfing the web. Why surf the web when you can surf the solar system?
All the consoles and science team face to the rear of the cabin. The team includes the Mission Director, Science Flight Planner (Mission Director II), telescope operators, Airborne Ambassadors, and instrument teams. These instrument teams are assigned to their specific instrument. They include: three data acquisition scientists who monitor the collection and storage of data, four data reduction scientists who interpret initial data results, and of course three telescope operators.
Surprisingly, most of the time, very few, if any, actual NASA employees are onboard besides the flight crew. Some of the crew are employees at USRA, which is a public non-profit organization and NASA contractor. The telescope operators work for both USRA and DSI (the German Sofia Institute, based at the University of Stuttgart). The flight crew is a mix of NASA staff and L3 subcontractors.
The rear bulkhead of SOFIA is where the aircraft appears most like the International Space Station. Insulation, plumbing, and fuselage are exposed to the cabin with fairly crude sidewall and ceiling panels covering re-routed control surface wires and electrical plumbing. The rear-facing position of the consoles affords everyone a view of the instrument which is mounted on the cabin side of the pressure bulkhead. Humorously, in what looks like a joke, an inflated plastic bag with a hand drawn snowman on it is attached to the FiFi-LS instrument. The bag is actually a low-tech indicator for a cryogen dewar – an inner core filled with liquid helium to allow the instrument’s temperature to equalize to exposed atmosphere when the fuselage door is open.
There are no pre-taped or flight attendant safety briefings on SOFIA! Instead, everyone informally gathers mid-ship to hear the safety precautions. We are warned that during flight, all crew and observers are to stay away from telescope for safety reasons because there are pinch points around the telescope that could be dangerous if anyone is caught up in them. I learned that the hard way when I approached the telescope a bit too closely and was yanked back by “the long arms of the law,” SOFIA’s Nicholas Veronico.
We were reminded to carry our fire mask with us at all times when leaving our designated seats as well. Another final announcement was made to remind us to keep all liquid beverages in closed thermoses and of course to praise the collection of the “bring our own catering” which is over-filling the gallery.
Captain Asher jokes that this prodigious amount of junk food will cause those who eat it to “screw up our weight and balance.”
Part Three: Back to the Future on a SOFIA Space Odyssey
In part three of this story, we’ll recall our experience flying SOFIA, a treat for any Airficcionado!