March 25th, 2011 by Kathryn Hansen
March 24, 2011
Greetings from Palmdale, California.
Our Goddard-based team is at Dryden Flight Research Center testing an instrument named MABEL, which stands for “Multiple Altimeter Beam Experimental Lidar”. MABEL is an ICESat-2 simulator, which we fly the instrument at high altitudes over various terrain to test the satellite’s measurement concept.
We were out here last December for MABEL’s maiden voyage. For the December deployment, we flew 5 test flights that included targets that would tell us about MABEL’s capabilities, such as ocean water, lake water, snow, salt flats, mountains, vegetated regions, and places where we had other datasets for ground control. I’ve attached a photo of MABEL before she entered the nose cone of the ER-2 (below).
We’ve returned to Palmdale to fly MABEL again to test a new set of filters that have been added to the instrument to filter out background noise, stemming from natural sunlight. These ‘etalon’ filters are a critical component to MABEL’s design, allowing us to fly during daylight hours.
So instead of being in the aircraft hanger until the middle of the night (like we were in December), we now have to arrive to the hanger super early … This ‘morning,’ two of us were awake between 3 a.m. and 3:30 a.m. In order to finish out this day, I have now had approximately eight cups of coffee today. I’ll write about our first flight tomorrow. Stay tuned …
About the blogger:
While at NASA, Kelly Brunt has been working on ICESat-2, where her duties include flight planning for Multiple Altimeter Beam Experimental Lidar (MABEL). MABEL is a high-altitude, airborne instrument intended to assess the new lidar concept associated with ICESat-2. Read more about Kelly here.
March 24th, 2011 by Kathryn Hansen
March 17, 2011
Another early morning wake up, with a quick check of the weather. I went to bed last night with snow falling, and not so promising satellite pictures showing a fairly significant storm system off to our west. I was thinking that we would be cancelled due to weather, but woke up to surprisingly calm conditions. The system skirted by us to our west and headed due south rather than east. The weather conditions here in the Arctic are much different from home, and I am still trying to figure out how the weather systems move about the area. I created a picture from this morning’s satellite image, with approximate locations of Thule, and our proposed flight path. You can see the major part of the weather was to our west, and we had some high clouds in our operating area to the north towards the pole.
Today’s mission was another satellite underpass track, this time for the European Space Agency CRYOSAT platform. Take off was under relatively clear skies, and we got some great views of the surrounding mountains and glaciers around Thule. I am told that this was nothing compared to the upcoming land ice flights, but I was still in awe with the beauty of the ice flowing towards the sea, and the morning sunrise reflecting off the snow covered mountains. The calving front was clearly visible from our low altitude just after take-off. This is the area were the land ice meets the water, and at this time of year the water is still froze, so the sea ice sort of acts like a buffer to hold up the glacier. During the summer months, the sea ice retreats due to the warmer air temperatures, and the glacier flows freely into the water, and calves into icebergs.
About an hour and half into our flight, we reached the beginning of the data collection line. We dropped down to 1500 feet in attempt to get under the clouds to allow the instruments on board to collect data. Today, the cloud deck was down around 1,000 feet, so we had to fly below that level. This made for some spectacular viewing of the sea ice conditions.
After about 2 hours of flying our survey line, we had reached approximately 87.5 degrees north, only 150 miles from the North Pole. The P-3 made a wide S turn to back track on the same line that we covered on the way out. This gives the instrument teams, twice the data to be compared to the satellite that would be passing over our heads, taking similar measurements. Another 2 hours of data collection on the way back, and now we have just broken off the survey line and are heading back to base.
Happy St. Patrick’s Day everyone! I have yet to see a single sign on base advertising any sort of celebration, so we might just have to create our own. Midshipman Brugler departs tomorrow morning on the rotator flight back to BWI airport, so we will go out in search of some congratulatory Corned Beef in honor of his departure. I will be staying on here in Thule for at least one more week, hoping to get on the flight across the Arctic to Fairbanks, Alaska to survey the Navy Ice Camp. Weather permitting of course!
March 24th, 2011 by Kathryn Hansen
March 16, 2011
Today was the day I had been waiting for all week. It was the first flight day of the IceBridge operation out of Thule, Greenland. Flying today had a special meaning to me for a few different reasons. I recently was selected to become a Navy pilot, which is a goal I have been working towards for some time. Therefore, upon completion of graduate school, I will report to Pensacola Florida and begin flight training. I was able to talk to the pilots, flight engineers and air crewmen of the NASA P-3B who happen mostly ex-Navy guys which was a pretty cool experience for me. So not only was I constantly interacting with the scientists and engineers, but with the people actually flying the aircraft and allowing the mission to happen in the first place.
The day started early because we had to report to the aircraft by 0700, so I woke up got breakfast and headed right over to the hanger.
The actual flight, although a long mission, was nothing short of amazing. We flew a path known as “Connor Corridor,” a flight taking us from Thule to north of the Canadian Archipelago.
This was a “ENVISAT” mission meaning we would be flying over the sea ice and actually going over a region that an ESA ENVISAT satellite would look at later in the day.
This was really interesting for me since I am studying the sea ice variation in the Arctic; therefore it was cool getting to see firsthand what I am reading about in books and learning about in my classes.
Not only did I get to see some amazing scenery, I also learned a lot from the people taking measurements onboard. On the P-3B, there is a gravimeter, a few airborne topographic mappers (ATMs), some cameras for the digital mapping system (DMS), ku-band radar, snow radars, MCoRDS radars and a magnetometer. All of this equipment is collecting data and in fact a lot of the instruments’ measurements are used together with other equipment in order to give the most accurate depiction of the Arctic as possible.
We landed around 1600, making it about an 8-hour mission! Although it was long, it was an experience I will remember for a lifetime; I am excited to fly again tomorrow, hopefully the weather will hold out and let us get in the air once again.
March 24th, 2011 by Kathryn Hansen
March 16, 2011
My alarm clock was set for 5:30 this morning to wake up, shower, get some breakfast and be at the hanger no later than 7 a.m. for an 8 a.m. take off. The weather was good for our target area north of the Canadian archipelago (islands), to survey the sea ice beneath the ENVISAT (LINK) satellite overpass that would take place later on in the afternoon. Part of the goal of IceBridge is to compare measurements taken on the P-3 to those measured by the satellites orbiting overhead. Since the satellite has much better spatial coverage then our airplane, if we can get good agreement between its data and the P-3 data, then we can trust that the satellite data is good. This will be tested on another level later in the week (hopefully) when we fly over the Navy Ice Camp, north of Alaska, where they will have instruments on the ground that we will then compare both our plane and satellite data again.
What type of instruments do we have on the NASA P-3? A Laser altimeter called ATM (Airborne Topographic Mapper), measures the distance between the plane and the sea ice surface, which gives us an elevation measurement. There are multiple radars, including one that measures snow thickness on the surface of the ice. A gravimeter is measuring Earth’s gravitational field, which in turn tells us about the bathymetry, or sea floor below. A magnetometer is measuring changes in the Earth’s magnetic field, again to give us an idea as to what the sea floor below looks like. We also have three digital cameras pointed downward below the plane taking constant pictures of our flight path.
It took about 90 minutes to get to our first collection waypoint. Weather plays an important role for the data collection because clear skies are needed for the instruments to take proper measurements. This morning’s weather briefing looked like our collection area was going to be relatively cloud free. After the transit, we dropped down to 1,500 feet and switched all the instruments into collect mode. The weather was perfect, and viewing the sea ice out the window was breathtaking. Lots of people think of the Arctic as just a flat expanse of white. This couldn’t be further from the truth. There are all sorts of cracks (leads) and mountains (ridges), similar to tectonic plates. The ice below is constantly moving via the winds and currents, and those forces acting on each piece of ice makes for a very dramatic seascape. There are areas of open water, though only for a few hours, because the surface temperatures below are well below freezing (approximately minus 20 degrees Celsius). You can see varying stages of sea ice formation, where there used to be open water, and the re-freezing process has already begun. It was rewarding to talk trough the different ice types with Midshipman Brugler, who took the Polar Science course last year, and get visual confirmation on concepts we discussed in the classroom.
After approximately 2 hours of data collection at 1,500 feet, we turned the P-3 around and climbed to 17,000 feet. We collected data on the exact same track as our outbound leg, testing the instruments between low-level and high-level collection. The sea ice took on a much different perspective at this higher altitude. We could see individual features before such as actual blocks of ice piled up on each other at a ridge, but now we saw a much larger area, with decreased details. The ice still does not look flat, but more like a jagged jigsaw puzzle, with intermittent breaks in the ice. Both legs were equally exciting and I am looking forward to being back in the air again tomorrow … weather permitting!
March 17th, 2011 by Kathryn Hansen
March 14, 2011
Today was busy day; a cargo shipment arrived with some instruments for the ground stations at 1430, and the P-3 arrived from Wallops Island, Va., at 1535. The air temperatures were about 20 below zero, with wind chills around minus 30 degrees Celsius. I was able to get right outside the hanger, and actually shot some video and photos of the P-3 landing, from atop the taxi way stair truck. It was a bit hazy, with some blowing snow, so visibility was not the best, but I was able to snap some decent shots which would prove helpful later without knowing it at the time.
The P-3 seemed to land very nicely from my vantage point across the runway, and it proceeded to taxi around towards the hanger. When it was about a hundred yards away we noticed that there was something wrong with the front tire. It had blown out during the landing/taxi. Later the pilots would use my photos of the plane landing to verify that the wheel had proper alignment during final approach. Unfortunately, due to the repairs, we will not be able to fly our first mission until Wednesday, March 16, however, the instrument teams will be able to utilize this time to finalize ground station set ups and calibrations. Hopeful for a sea ice flight on Wednesday!!