Finishing the Arc

From Sarah DeWitt, NASA’s Goddard Space Flight Center

Nov. 10, 2010 – South Pole Flight #2

After two and a half days of waiting for a replacement part to be delivered from the United States to Punta Arenas, the Operation IceBridge team is back in the air again. A new landing gear latch was hand-delivered on Tuesday afternoon at 2:20 PM. At the daily 6:00 PM science meeting, the ground crew informed us that the latch had been installed and was ready for flight. There was a hearty round of applause and a smile on everyone’s face.

Based on the weather prediction for Wednesday, the team identified two possible flight paths: a pass over the Crosson Ice Shelf or an arc over the South Pole. Models showed a low-pressure system off of the Antarctic Peninsula, and relatively clearer skies over the pole. After a second weather report in the morning, it was decided that we would do the South Pole arc – the LVIS 86b flight line – a continuation of the 2009 LVIS 86 flight line. 

The latest weather model data. Credit: John Sonntag, NASA WFF/URS.

IceBridge project scientist, Michael Studinger (NASA GSFC/UMBC), contacted the station manager at the South Pole to let him know our approximate overflight time. Apparently for folks who have been stationed at the South Pole for weeks or months during winter, this is an exciting event! The only question is, will the skies be cloud-free so we can see the station and they can see us?

8:30 AM – Today is my first flight on the NASA DC-8, so after the pre-flight briefing I made my way up to the cockpit for a front row seat. Seated behind the pilot and beside the flight engineer I buckled up and donned my headset. 

The NASA DC-8 flight crew prepares for take-off. Credit: Sarah DeWitt, NASA GSFC.

9:20 AM – Take-off! It’s a beautiful day in Punta Arenas, and the view from the cockpit is spectacular. As we head straight south I can see Route 9, the highway that hugs the coast as you head south from town to Fuerte Bulnes and San Juan. The mountains to my left are jagged and absolutely smothered in snow. The tall one looks like the Matterhorn.

9:45 AM – Today’s flight navigator is Rick Auld, an Air Force rated navigator onboard the DC-8 through the NASA Alliance Agreement with Edwards Air Force Base. He delivers a map of the South Pole arc we will fly today. The pilots explain to me that we’ll fly through enough time zones to go through Wednesday, Thursday and back again. 

The DC-8 pilots point out the narrow Antarctic time zones on the navigation map. Credit: Sarah DeWitt, NASA GSFC.

10:47 AM – Rick informs me we are about 160 miles due west of Adelaide Island. We are high above the clouds – a blanket of white in all directions.

10:50 AM – Just passed the Antarctic Circle, and we’ll begin our climb to 35,000 feet. It could be my imagination, but the highest layer of clouds look to be thinning a bit.

10:58 AM – Mission manager Frank Cutler, NASA DFRC, announces that we’re approaching the Antarctic continent, and asks the science instrument teams to check-in and declare readiness. The air is getting a bit bumpier now – the high clouds are back.

11:03 AM – Gap in the clouds ahead! The LVIS science team will use this opportunity to do some of their instrument maneuvers. Meanwhile I am catching my first ever glimpse of Antarctic ice. 

Shane Wake and Bryan Blair – LVIS engineer and principal investigator at NASA GSFC – take a look at the LVIS instrument read-out in their station near the rear of the aircraft. Credit: Sarah DeWitt, NASA GSFC.

11:20 AM – Michael informs me that we’re currently flying over the Wilkins ice shelf – or remnants of it. It broke up just a few years ago, so many very large icebergs are left floating in the sea. Image: Remnants of the Wilkins ice shelf from the window of the NASA DC-8. Credit: Sarah DeWitt, NASA GSFC.

11:32 AM – Thick cloud cover again. Time for lunch.

12:05 PM – Bryan shows me the ICESat data points we’ll be flying over today. Our path starts with a very high-terrain area over the Transantarctic Mountains and then levels out towards the end. We hope to see the mountains over top of the clouds. Some of the peaks rise to 10,000 feet, so it’s certainly possible. The flight today will enable LVIS to record a wide swath of data covering nearly every single orbit that the ICESat satellite made. Because of its polar orbit, millions of ICESat data points are clustered around the pole. During ICESat’s 7-year lifetime, its laser instruments were turned off and back on again from time to time, so there are slight differences throughout the dataset. LVIS data will provide a statistically powerful tool to calibrate the ICESat data.

12:15 PM – Rick tells me we’re 736 miles from the South Pole. Of course, we’re not flying a straight line, so it will take longer than that before we reach the pole. We’ll actually be flying an arc around the pole at 240 miles distance before crossing over the South Pole station. Clouds are still pretty heavy. We’re approaching -80 degrees latitude. 

Screen shot of Falcon View navigation map showing the flight path arc around the South Pole at a distance of 240 miles. Credit: Rick Auld, United States Air Force.

1:20 PM – We’ve just begun our arc around the pole. A layer of very smooth flat clouds blankets everything, but a few Transantarctic peaks appear in the distance. The clouds have cleared for a moment and I can see the subtle ridges that appear on the surface of the Antarctic ice. It is absolutely desolate – no signs of movement other than the clouds and the wind-blown textures atop the ice.

1:50 PM – The view is much clearer now – a stroke of good luck, since we’re passing over one of the world’s most spectacular mountain ranges. Just flew over some beautiful jagged peaks and glaciers. 

View of a Transantarctic mountain glacier from the DC-8. Credit: Sarah DeWitt, NASA GSFC

2:10 PM – We’re rounding the bend away from the mountains and onto the Antarctic plateau. We’ve passed the halfway point of our arc, and we’ve also entered the Eastern hemisphere. Apparently it’s now 4 AM on Thursday.

2:53 PM – We’ve gone half way around the world in 126 minutes. Our LVIS 86 arc is complete and now we’re heading up to 39,000 feet and flying straight towards the pole. We’re also heading straight into the sun! I’m glad I have my sunglasses.

3:10 PM – DC-8 co-pilot Dick Ewers (NASA DFRC) is talking to the South Pole on radio headset. They are ready for us to fly over. The sky is clear so they should be able to see us just fine. This has got to be one of the most amazing things I’ve experienced. Listening to the conversation between our NASA crew and the scientists at the South Pole station makes me feel very proud to be a member of this team.

3:28 PM – We are flying directly over the South Pole. The place to see it is from the cockpit window, or the nadir view camera mounted inside the bottom of aircraft. I’m squeezed in between the pilot’s seats to catch a few snapshots. Meanwhile, the compasses are spinning like crazy. 

View of the South Pole Station from the DC-8 cockpit. Credit: Sarah DeWitt, NASA GSFC

3:50 PM – Now we’re heading on a straight line from the South Pole, following the exact track we did a few days ago, just before I arrived in Punta Arenas, in order to mimic the ATM swath and compare datasets.

The smooth edge of floating sea ice off the western coast of the Antarctic Peninsula (right). Credit: Sarah DeWitt, NASA GSFC

6:25 PM – The last few hours have been extremely relaxed and quiet. Seems like everyone is conserving energy. I’m doing some yoga stretches. We should be back in Punta Arenas in a few hours. Meanwhile, the team has started looking at flight options for tomorrow. If the weather holds, we’ll do a low elevation zig-zag pattern over parts of the peninsula.

6:35 PM – We’re crossing over the edge of the Antarctic sea ice. It’s remarkable how smooth the edge is. A few lonely icebergs are floating nearby. I can see their blue color below the surface. The sun is casting a gorgeous pink-orange glow over the ocean surface.

6:40 PM – And just when I declared that everything was relaxed and quiet, the crew performed a couple of pitch and roll maneuvers. Wow!

9:25 PM – Landed after 12 hours of flying. The sunset over the Andes was worth the wait. Tomorrow I hope to fly again.

2 thoughts on “Finishing the Arc”

Comments are closed.