Atmospheric Perturbations around Eclipse Path (APEP)

  • Mission
  • Vehicle
  • Launch
  • Photos

This campaign is named Apophis after the cosmic world serpent from ancient Egyptian cosmology. The serpent pursues the sun god Ra, and every so often, nearly consumes the sun disc, resulting in an eclipse. This first round of APEP launches occured during the Annular Solar Eclipse on October 14, 2023 from White Sands Missile Range, NM. A second round is scheduled for the Total Eclipse on April 8, 2024 from Wallops Island, VA.

The APEP rockets were designed to collect data to answer the following science questions:
Does the eclipse shadow directly seed discernible irregularities in the mid-latitude ionosphere? What are the associated vertical length and time scales of these irregularities?

What are the impacts of the Temperature Gradient Instability (TGI) and Gradient Drift Instability (GDI) in seeding small scale (10s to 100s of meters) ionospheric irregularities in the presence of solar eclipse?

How do the various regions of the ionosphere behave differently at small scales in response to the overall cooling effect of the thermosphere?

Three identical payloads were launched during the Annular Eclipse occuring October 14, 2023. The first payload was launch approximately 35-minutes before peak eclipse, the second at peak, and the third 35-minutes past peak.

This was the first time for simultaneous multipoint spatio-temporal in-situ observations of electrodynamics and neutral dynamics associated with solar eclipses. The main payload instrumentation included Langmuir probes, electric field probes, magnetometers, ionization gauges, and accelerometers. The simultaneous multipoint measurements were facilitated by four deployables ejected from each payload that are instrumented with Langmuir probe, magnetometer and accelerometer.

Co-Investigator institutions include Air Force Research Labs, Dartmouth College, Massachusetts Institute of Technology, and University of Colorado-Boulder.

The Principal Invetigator is Dr. Barjatya/Embry-Riddle University

More on APEP: https://science.nasa.gov/solar-system/skywatching/eclipses/solar-eclipses/2023-solar-eclipse/to-study-atmosphere-nasa-rockets-will-fly-into-oct-eclipses-shadow/

APEP fact sheet

Embry-Riddle University APEP information

Drawing of a Terrier-Black Brant sounding rocket

The Black Brant 9 is a two stage sounding rocket with a Terrier first stage and Black Brant second stage. The Black Brant 9 can reach altitudes of about 600 km. Payloads weighing from 400 to 1200 pounds can be flown.

Additional sounding rocket vehicles

Google Earth Map showing White Sands Missile Range.

The Apophis mission was launched from White Sands Missile Range, NM, on October 14, 2023.

Photos not currently available.