Atmospheric Drag Impacts On Satellite Orbits
September 12, 2013

DANDE Thermosphere-Studying Satellite To Launch On Sunday

redOrbit Staff & Wire Reports - Your Universe Online

A beach ball-sized satellite designed to investigate the impact that atmospheric drag can have on satellite orbits is slated to be launched by NASA on Sunday, September 15.

The satellite, which is known as the Drag and Atmospheric Neutral Density Explorer (DANDE), was designed and built by students at the University of Colorado Boulder. It will depart from Vandenberg Air Force Base in California and be carried into space aboard a commercial Falcon-9 SpaceX rocket.

DANDE was created in order to study how the Earth’s thermosphere varies in density at altitudes from about 200 to 300 miles above the surface. There are thousands of satellites in orbit at those altitudes, the university said, and the majority of them eventually degrade, lose altitude and burn up in the atmosphere.

The thermosphere is often affected by space weather caused by variations in solar activity, according to Brian Sanders - who serves as the deputy director of the Colorado Space Grant Consortium (COSGC) and who helped oversee the students who built the probe – and the amount of drag on a spacecraft increases as the density of the thermosphere increases.

DANDE, whose primary investigator is COSGC Director Chris Koehler, is equipped with an accelerometer, a wind and temperature spectrometer, an onboard computer, an orientation control system and radio equipment which will be used to transmit data back to Earth in real time, the university said.

“The accelerometer aboard DANDE can sense the movement, speed and direction of the satellite to help scientists better understand drag forces,” they added. “A second onboard instrument, the wind and temperature spectrometer, will provide information on the changing drag forces present in the thermosphere by identifying what kind of particles are impacting the spacecraft as well as their angles and collision velocities.”

“All satellites experience drag, which causes their orbits to degrade over time,” added Miranda Link, a general astronomy major who serves as co-leader of the DANDE project (along with aerospace engineering sciences major Brenden Hogan). “Knowing more about the drag forces and how they change is information we think would be valuable to any groups flying satellites, whether they are from the government or commercial sector.”

Hogan explained that changes in the thermosphere can often times be “quite drastic,” especially when major solar events are occurring. Obtaining more data that satellite users have on how thermosphere changes will impact their probes will better help them plan ahead in order to prevent problems from occurring, Hogan added.

Link noted that the DANDE satellite launch date was beneficial because of its close proximity with a “solar maximum” – an event during which the Earth’s approximately 11-year solar cycle reaches peak activity. She added that the Colorado research team believes that the solar maximum will result in increased solar activity and a greater impact on the atmosphere – giving the DANDE team an opportunity to collect copious amounts of data.