Archive for April, 2011

MABEL: Spring 2011: One Final Note from Dryden

April 8th, 2011 by Kelly Brunt

MABEL: Flying on a high-altitude aircraft at the brink of space, the MABEL instrument is helping scientists to simulate measurements from NASA’s next ice-observing satellite, ICESat-2.

April 8, 2011

Today, I caught this video on the NASAexplorer channel on YouTube:


It covers Jake Bleacher’s work in understanding lava-sheet inflation
(see his video, which covers this interesting geologic process). On
MABEL’s last mission (4/5), we surveyed some of Jake’s sites in both
Arizona and New Mexico.

The lava sheets that Jake studies are very broad, flat regions. For
his work, he has kinematic GPS data across sections of these sheets.
We mimicked Jake’s traverses (from 65,000 feet up) to gather
ground-truth data for MABEL. Additionally, because MABEL samples in a
swath pattern, as opposed to just over a single point, we hope to
provide Jake with additional information about his survey areas.

MABEL is an airborne simulator of the laser altimeter that will be
aboard the ICESat-2 satellite. ICEsat-2 is designed to look at ice
sheets, not lava sheets. So this MABEL mission  over Jake’s sites
represents the cooperative nature, typical of the different geoscience
disciplines, at Goddard Space Flight Center.

Well, we are pretty much finished out here. The engineers flew home
today and there are only a couple of us still here, flying out
tomorrow. We hope to return to the field with MABEL sometime later in
the summer.

MABEL: Spring 2011: MABEL flies her last science flight for Spring 2011

April 8th, 2011 by Kelly Brunt

MABEL: Flying on a high-altitude aircraft at the brink of space, the MABEL instrument is helping scientists to simulate measurements from NASA’s next ice-observing satellite, ICESat-2.

April 7, 2011

MABEL flew her final science mission of 2011 (4/5) over White Sands Missile Range. The weather over this area was clear when we flew it, however, weather rolled into the area just as the plane left our target.

White Sands as seen from an elevation of 65,000 feet. Credit: NASA/Tom Ryan

White Sands was chosen as a MABEL target because we have been using the area as a ground-control site since ICESat was launched in 2003. Two ICESat tracks crossed in the center of the dune field; where they cross, ICESat researchers have recently planted reflectors that we hope to see in the MABEL data. These reflectors will help us validate MABEL’s elevation determination accuracy.

Also on this flight, we also attempted to collect data from deciduous trees in Arkansas. From Dryden Flight Research Center, to New Mexico, on to Arkansas, and then back to Dryden is a 9 hour mission.

Our ER-2 pilot refueled with caffeinated chocolate pudding. Credit: NASA/Tom Ryan

However, between White Sands and Arkansas, MABEL’s laser stopped firing. This is not something that we were prepared to deal with in the field. So, given that we were already near the end of this mission, we decided we’d call this trip a success, given all that MABEL had already accomplished and given the science objectives that the instrument deployment had met:

1) Hit ground-control points set up at White Sands to validate MABEL
2) Collect tree data for ICESat-2 vegetation scientists
3) Collect snow data for ICESat-2 glaciologists
4) Collect data over the ocean and bright clouds for ICESat-2 instrument scientists

We are now headed home. We have had a fantastic time working with the pilots and mechanics here at Dryden Flight Research Center. They are great at what they do, making their components the smoothest parts of the complex MABEL equation. We might not have any other missions on the ER-2 this spring, but you can still follow their flight activities at their Twitter feed: @NASA_Airborne.

MABEL: Spring 2011: MABEL Collects Snow Data!

April 6th, 2011 by Kelly Brunt

MABEL: Flying on a high-altitude aircraft at the brink of space, the MABEL instrument is helping scientists to simulate measurements from NASA’s next ice-observing satellite, ICESat-2.

April 5, 2011

Credit: NASA/Tom Ryan

We had another highly successful mission, this time to Colorado (4/1/2011).

Specifically, we targeted a field that usually holds snow late in the season. Additionally, we targeted SNOwpack TELemetry (SNOTEL sites), where we have good control with respect to snow cover. One last site we targeted was a SNOTEL site situated within Loveland Ski Area, which was reporting one new inch of snow in the past 24 hours.

The weather looked slightly spotty to the north, but the pilot reported that there were clear skies over our targets!

We can actually receive limited information from the instruments during flight. So during the flight we knew that MABEL was operating properly. Additionally, we can get a very good sense of the cloud cover by looking at real-time data from an instrument that is flying along-side MABEL. It’s called CPL, or Cloud Physics Lidar. CPL records a smaller volume of data and has very mature software, relative to MABEL. So it’s easy to use CPL as a real-time assessment of atmospheric conditions during the flight. So we tend to fly CPL regularly with MABEL.

Because our pilot had a ton of transit time between Dryden and our targets in Colorado, we asked him for a huge favor: We asked him to take photos for our project. Keep in mind that he is in a pressurized suit, so everything he does, he does wearing bulky gloves. So we were very happy when he returned these amazing photos. Phenomenal.

The pictures (above and below) were taken from 65,000 feet above sea level. At this elevation, you can clearly see the curvature of the earth. Additionally, you can see the thinning of the atmosphere (apparent in the change in color of the sky from light blue to dark blue).

Credit: NASA/Tom Ryan

Credit: NASA/Tom Ryan

Credit: NASA/Tom Ryan

MABEL: Spring 2011: Over the Sierras, Third Flight’s a Charm

April 4th, 2011 by Kelly Brunt

MABEL: Flying on a high-altitude aircraft at the brink of space, the MABEL instrument is helping scientists to simulate measurements from NASA’s next ice-observing satellite, ICESat-2.

April 4, 2011

Palmdale, Calif. – Well, it took three tries, but we finally collected excellent MABEL data over a forested area in the Sierras.

While we were flying the first attempt (3/28), the detector temperature kept drifting out of the acceptable thermal range. So MABEL would temporarily shut down to cool itself. The temperature for the detector has to be remain very close to 32
degrees, so we need to keep very close control over the temperature of the instrument. After landing, it was determined that the problem stemmed from the fact that MABEL’s cooling system had not been completely flushed. That was fixed for the next flight.

At some point during the second flight over the Sierras (3/29), MABEL’s GPS failed. We use the GPS signal for precise positioning, but we also use it for very precise time. GPS satellites broadcast very precise time (which is also exploited by seismologists). We use the GPS signal to measure the exact time between the laser firing and the detector receiving that signal. So without the GPS data, our laser data was pretty much worthless.

Instrument issues are common during deployments. The engineers associated with MABEL are quick to address them so that the week’s flight schedule stays intact.

In the photos attached, Eugenia DeMarco, of Sigma Space Corp., works in the nose cone, where MABEL rides. Credit: Ryna Cargo, Sigma Space Corp.

Dan Reed, of Sigma Space Corp., and Andrew Kupchock, of SSAI, diagnose MABEL while the pilot readies for take off.

The third flight to the Sierras (3/30) was the clearest weather that MABEL had ever seen! It was what we had always been told was standard ‘southern California weather.’ And the flight itself went off without a hitch.

We are interested in a forest in the Sierras to assess MABEL’s ability to measure the top of the trees (the top of the tree canopy) and the ground beneath. These measurements give vegetation scientists an assessment of the biomass associated with these particular trees, which are evergreens. Later in the mission, we will try to collect similar data over Arkansas, or deciduous vegetation. Information from these flights will be incorporated into ICESat-2′s algorithms.

More from Dryden later!