NASA 747, Cleared for Take-Off: Observing a SOFIA Mission

Every summer, NASA’s airborne observatory SOFIA leaves its base in Palmdale, California, and heads to Christchurch, New Zealand to observe the Southern Sky.

Being in the southern hemisphere for a couple of months not only allows scientists to observe celestial objects that cannot be seen from the Northern Hemisphere, but it also allows them to escape the hot and humid summer atmosphere which is not ideal for astronomy.

Back in June, I was able to join one of the 25 flights that SOFIA did as part of its 2018 Southern Deployment and see the airborne observatory in action. In this article, I will take you onboard that flight.

NASA Boeing 747SP SOFIA N747NA at Christchurch Airport
NASA SOFIA Boeing 747SP, N747NA.

 


This is the fourth and final article in a four-part series detailing the history and operations of the world’s largest airborne observatory, Stratospheric Observatory for Infrared Astronomy also known as SOFIA. The following articles are included in the series:

  1. Introduction: Experiencing SOFIA’s Southern Deployment 2018 in Christchurch – An introduction to the series giving an overview about my experiences with SOFIA.
  2. From a Learjet to SOFIA: A Brief History of the World’s Largest Flying Telescope – A brief look at the history of airborne astronomy and a look at how SOFIA came to be.
  3. “Per Aspera Ad Astra:” The Complexities of Operating SOFIA – A detailed look at the variety of teams involved in the operation of SOFIA and the challenges faced by them.
  4. NASA 747, Cleared for Take-Off: Observing a SOFIA Mission – A briefing-to-landing account of my flight onboard SOFIA.

 

The SOFIA Experience Begins

Having received an email saying “I will need you at Gate 3 at 1730, ready to fly,” the day before the flight, I arrived at Christchurch airport a couple of minutes before that. Soon after, one more journalist who would be covering the flight, Dennis, arrived.

First, we were escorted into a briefing room inside the United States Antarctic Program hangar by Nick, SOFIA’s Communications Manager. There, we were first taken through egress training by one of the SOFIA staff before the rest of the team arrived and the mission briefing begun.

Given that very little of SOFIA’s interior resembles a passenger airliner, the instructions were unlike any other I’ve seen before.

Like one would expect, there was some overlap – the video mentioned the usual seatbelts and oxygen masks among other things. But, on top of those, safety devices such as inertia reels for evacuating through the flight deck emergency escape hatch and a ladder for evacuating through an emergency exit by the nose gear were introduced.

EPOS (Emergency Passenger Oxygen System), a self-contained hood with a built-in oxygen tank was mentioned as well. In fact, we were required to carry it around on the flight whenever we were out of our assigned seat – which was more or less throughout the whole duration of the flight.

EPOS (Emergency Passenger Oxygen System)
EPOS (Emergency Passenger Oxygen System) serves as a replacement for overhead oxygen masks that you would find on a typical passenger aircraft.

Mission Briefing: Going Over the Flight’s Details

Not long after the egress training was finished, that night’s Mission Director (MD) – Randy – as well as the rest of the team entered the room in preparation for the mission briefing. Before jumping into the nitty gritty of the flight we were about to board, Randy presented another team member, Oliver, with a patch congratulating him for getting over the “100 SOFIA missions flown” mark.

The briefing itself begun with the MD informing everyone about that night’s flight times:

  • 7:40PM door close
  • 7:55PM engine start
  • 8:25PM taxi
  • 8:37PM take-off
  • 6:29AM landing

A roll-call as well as a status check of the aircraft and instruments onboard followed before the pilots mentioned that one jump seat was available for each take-off and landing, and the project’s Principal Investigator, Dr. Rolf Gusten, briefed us about the details of the observations to be made during the mission.

NASA SOFIA Mission Briefing
Before every mission, the night’s team gathers in the briefing room to go over the flight’s details.

After that, a slide about “instrument considerations” followed. As we were flying with the very sensitive GREAT (German REceiver for Astronomy at Terahertz Frequencies) instrument we were told to switch our phones and smartwatches off to avoid affecting the collected data. We were also notified that there would be no microwave onboard for similar reasons and that the cabin would be kept fairly cold throughout the flight.

Finally, a short presentation about safety onboard and a quick slide about “getting to SOFIA” followed before the team broke off to prepare for the flight and we headed to the aircraft.

NASA SOFIA Millenium Falcon
A slide explaining how to get to Millennium Falcon… I mean, SOFIA.

First Moments Onboard SOFIA

Outside, it was dark and cold, and the ground staff was in the process of preparing SOFIA for the night’s mission. While making our way to the aircraft, we stopped along the way a couple of times to get exterior photos.

Climbing the “NASA-branded” stairs, I could not believe I was about to get onboard SOFIA for the second time (I did a ground tour of it the day before) – and this time I was actually going to fly on it!

NASA Boeing 747SP SOFIA N747NA at Christchurch Airport
SOFIA – the only Boeing 747SP in the world equipped with a large infrared telescope.
SOFIA Ground Preparations
While SOFIA uses the Antarctic Program’s facilities in Christchurch, it uses its own stairs.

Given that the area near the telescope becomes a no-go zone once in the air, before everyone got onboard, we had a closer look at the telescope located in the rear part of the aircraft. With the GREAT instrument and other devices attached to it, it looked like something out of a science-fiction movie.

NASA SOFIA Telescope
A close-up look at the telescope and the GREAT instrument.
NASA SOFIA Telescope
During the flight, the telescope was a no-go zone.
NASA SOFIA Telescope
The GREAT instrument.

As our scheduled departure time got closer, the rest of the mission team got onboard one after another, and once everyone got settled, we all gathered next to the 747SP’s signature spiral staircase for a quick safety briefing which ended with everyone checking their cellphones one last time to make sure that they were off and that we were ready to collect useful and accurate data.

NASA SOFIA Pre-Departure Safety Briefing
A safety briefing was held near the aircraft’s staircase once everyone was onboard.

Christchurch, We Have a Problem

With the mission ready to start, I climbed up the SP’s spiral staircase and entered the cockpit where I joined the two pilots, Craig and Dave, as well as the flight engineer, Tom, for take-off. While the flight engineer’s workstation was full of analog instruments like one would expect from a classic 747, the pilots’ panel mostly consisted of digital screens – a result of an avionics update SOFIA went through in 2012.

Not long after I settled in the jump seat, the mission director came to the upper deck to inform the cockpit crew that we were having an issue with the communications system.

If it couldn’t be resolved, we would have to abort the mission since there would be no easy way for the mission director to communicate with the flight deck – something that is extremely important when even a one-degree course adjustment can mean the difference between getting the desired data and going home empty-handed.

Luckily, the communications issue was resolved in less than half an hour, and we were good to go. Or, so we thought until the pilots proceeded with starting up SOFIA’s four Pratt & Whitney engines.

NASA SOFIA 747SP Cockpit
The cockpit crew preparing the aircraft for departure.

The crew encountered a problem when starting engine number four, and after analyzing the problem, they estimated that it would take about 90 minutes to fix.

While on a typical airline flight that would mean “just” an inconvenient delay, on SOFIA’s science flights, even the shortest delays can mean that the planned observation would not be possible, canceling a valuable science flight. As such, Randy had to check with the science teams about what would be the latest time we could take off with them still having enough observation time to do the necessary observations.

During that time, I left the cockpit and headed back to the lower deck, hoping that the issue would be resolved in time for our flight to still proceed.

NASA 747, Cleared for Take-Off

After what felt like forever but was in fact only about half an hour, the pilots informed the mission director that the engine problem was resolved and that we could proceed with the flight. As such, I headed to the upper deck and got into the jump seat once again – this time actually staying in it until we took off.

Receiving the appropriate clearances, the cockpit crew started up the engines and taxied to RWY20. Then, “NASA 747, cleared for take-off” could be heard through the radio before the engines spooled and we got off into the dark and cold Southern Sky. It was unbelievable that in spite of all the complications, we took-off with just a couple of minutes of delay.

As we climbed to our initial cruising level of 37,000 feet, the science teams on the main deck were setting up their systems to begin the observations. Around that time, Randy got in touch with the flight engineer over the intercom: “Tom, we need to lower the upper deck temperature, the guys are unable to turn the cryo-cooler into flight mode.”

NASA SOFIA Flight Engineer
The flight engineer adjusting the temperature on the upper deck.

Without the cryo-cooler working, the GREAT instrument could not be operated as it would overheat. Without the instrument working, the science teams could not collect the required data. Without the ability to collect data, the mission would have to be terminated and we would return to Christchurch.

As such, it was not only a matter of getting the cryo-cooler working, but getting it working soon enough to leave plenty of time to do the necessary observation.

With Tom lowering the temperature multiple times, the cryo-cooler finally entered into flight mode and since there was enough observation time to spare, the mission could continue! And, the upper deck temperature could be raised back to moderate temperatures.

NASA 747SP Temperature Control Panel
A close-up of the temperature control panel.
Cockpit Data Printer
Cockpit data printer.

Time for Natural Wonders

Not long after the cryo-cooler issue was resolved, I heard: “Do you still have the guest upstairs? Please, send him down,” on the intercom, and so I got out of the jumpseat and descended to the main deck where all the teams were busy carrying out the mission.

By this time, the telescope door was wide open. To be honest, though, it took me a while to realize that since I did not notice when the door was opened. There was not even the slightest shake – very impressive given that opening the door literally made a dent in the fuselage that was several meters across!

Main Deck of SOFIA
Overview of the main deck.
SOFIA Telescope Status Display
Telescope status display.

What followed is something I will never forget. I noticed people looking out the window and so I did too. And, when I looked out, I couldn’t believe it – there was the Aurora Australis. While it started rather dim, as time passed, it became brighter and brighter and provided for an amazing show.

Besides seeing the Aurora itself, it was also great seeing the SOFIA staff looking out of the window and enjoying the moment – talk about a job with perks.

After watching the Aurora from the main deck for a while, I was invited to the upper deck to see it from the cockpit – an invitation that’s hard to refuse. While I was unable to get a good photo of the Aurora from there, I did enjoy seeing it together with the flight deck instruments and was quietly jealous of the views the pilots had.

Aurora Australis
Aurora Australis together with a 747SP wing – by far the best window view I’ve ever had.

As if the above was not enough, looking out of the window, someone said “check out the cracks in the ice.” Hearing that, I looked out of the window again – and for the second time in a very short period of time – I was amazed by what I was seeing.

We were past the Antarctic Circle by now (the flight I was on happened to be the southernmost flight of SOFIA to date), and thanks to the full moon, we could see ice in the Southern Ocean right below us. It was truly a magical moment.

Unfortunately, it didn’t last too long as soon the skies below us became a bit hazy and cloudy. But, I will never forget the view we had for a brief moment!

NASA SOFIA Flight Plan
This mission was the southernmost SOFIA flight to date and the first one to cross the Antarctic Circle.

SOFIA in Action: The Upper Deck

With the Aurora fading away and the ice hidden below clouds, it was time to tour the aircraft a bit more and to learn more about SOFIA from its team members.

The upper deck consisted of three parts – the cockpit, a small passenger compartment, and a compartment housing the cryo-cooler. In the passenger compartment, there was a large desk together with four ex-Lufthansa business class seats and a flight engineering console.

In the cockpit, the three flight crew members were focused on flying SOFIA based on the flight plan and instructions from the mission director. In fact, shortly after take-off, the pilots requested and were granted the permission to deviate up to one degree and twenty miles of our filed course to “conduct science” – something that the mission director took advantage of numerous times throughout the flight.

NASA SOFIA Upper Deck
A view of the upper deck. The cryo-cooler was behind the white door.
NASA SOFIA Cockpit
SOFIA’s cockpit crew at work.
Flight Engineer
The flight engineer filling out the flight’s paperwork.
CDDS (Cavity Door Drive System)
CDDS (Cavity Door Drive System) control panel used to operate the telescope door.

SOFIA in Action: The Main Deck

Back on the main deck, the mission was in full swing, and so I hanged around the various sections of the main deck while talking with members of the different teams and observing them at work.

Stationed closest to the telescope were two teams – the telescope operators at a workstation on the starboard side of the aircraft and the instrument team at a workstation in the middle of the 747, right in front of the instrument.

The mission was staffed with two telescope operators – Will and Shannon. Together, with the help of about ten screens, they were monitoring whether the telescope was functioning properly and aimed at the right “tracking star.” While an error popped out on one of their multiple screen every now and then, each of them was, impressively, taken care of within seconds.

The instrument team consisted of half-a-dozen or so scientists including one from Finland and one from Japan who were making sure that GREAT – the instrument attached to the telescope that night – was working well.

NASA SOFIA Telescope Operators
Telescope operators at work.
NASA / DLR / USRA / DSI
Logos of the main organizations behind SOFIA embroidered in the cabin walls.
Guiding Cameras SOFIA
Besides the main instrument, SOFIA is also equipped with three guiding cameras images of which can be seen on this screen.
NASA SOFIA Instrument Team
Instrument team at work.
Yoko NASA SOFIA GREAT
Yoko – a Japanese member of the GREAT instrument team.

Going towards the front of the aircraft, there was a couple of workstations used by scientists and other support staff to do their work, and there was the mission directors’ workstation.

The night’s two mission directors – Randy (MD) and Gabrelle (MD II) – were busy monitoring the progress of the mission overall including our actual position as compared to our planned position, and liaising between the science teams on the main deck and the flight crew in the cockpit on the upper deck.

NASA SOFIA Mission Directors
Mission directors at work.
NASA Mission Director
Besides the fixed workstations, many of the team members including Randy also had their laptops onboard.
NASA Mission Director
Gabrelle monitoring our position on the flight map.

Near the aircraft’s spiral staircase, there was a counter where the team could get snacks. There was also a pair of refrigerators – one full of water bottles and the other one used by the crew members to store their meals.

Snacks
Snacks.
Lunch
Yoko enjoying her meal.

Finally, at the very front of the 747SP – where airlines would have their business or first class cabin – there were ten ex-Lufthansa and two ex-United business class seats which the staff could use to relax in during the long, 10-hour, all-night mission and which were also used by some of the supporting staff and guests during take-off and landing.

Besides that, the nose section also housed the MCCS – Mission Control and Command System – the computer used to integrate all of the different parts of SOFIA.

NASA SOFIA 747SP Cabin Nose Section
The nose section was the only part of the cabin that looked even remotely close to what the aircraft looked like in its airline service.
NASA SOFIA Seat Cover
SOFIA-themed seat cover.
MCCS
Part of the MCCS (Mission Control and Command System).
NASA SOFIA Patches
A collection of SOFIA’s mission patches.

Landing Back in Christchurch

While I would have loved to be able to observe the SOFIA operations for many more hours, unfortunately, the seatbelt signs being switched on shortly after 6AM signaled that the mission was coming to an end. As such, I packed up my camera and settled down in one of the business class seats in the nose section in preparation for landing.

NASA SOFIA Fasten Your Seatbelt
The classic “No Smoking / Fasten Seat Belt” signs gave a hint about the aircraft’s age.

The mission came to a definitive end when we landed at still-dark Christchurch airport at 6:22AM, and several minutes later, we came to a full stop at the same parking spot in front of the Antarctic Program hangar that we left about ten hours earlier.

To recap the flight, we departed on Tuesday, crossed the International Date Line and flew briefly into Monday before crossing it once again and landing on Wednesday. Along the way, we managed to cross the Antarctic Circle, see Aurora Australis as well as ice in the Southern Ocean. And, do a lot of science, of course.

What a memorable flight!

Flight Plan
Flying back towards Christchurch.
Crossing the IDL
Notice the longitude – taken shortly after crossing the International Date Line back into Monday.

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