Hopkins, Randall C.

Pitalo, Kenneth

Reardon, Patrick J.

Spann, James F.

Stahl, H. Philip

NASA Technical Reports Server

The Geospace Dynamics Observatory (GDO) 
A paradigm-changing geospace mission
GDO Mission Concept
• Orbit: 60-Re circular polar orbit = 27-day period, 
long-term viewing of regions of interest
• 2.4-m optics = required sensitivity for faint signals
• 1.5-degree FOV = full access to near-Earth space
GDO Optics & Instruments
The GDO mission observes geospace with 
unprecedented resolution, scale, and sensitivity using:
• Three far ultraviolet, co-aligned simultaneous 
auroral imagers—135, 150, 170 nm, 4 nm FWHM
• An extreme ultraviolet, wide field-of-view 
plasmasphere imager—30.4 nm
• A spectrometer in the near to far ultraviolet 
range that will probe any portion of the disk and 
simultaneously observe the limb—120–300 nm, 
1 nm resolution
The GDO optical design
• Separates the FOV into reduced regions
• Each region can be corrected individually
The GDO measurement characteristics
• Full Earth disk image composite
• Spatial resolution of  <2 km at nadir
• Pointing accuracy 0.2 arcsec
• Pointing resolution 0.5 km, knowledge 0.2 km
• Integration time of 1 sec
• Sensitivity of 100 R with SNR = 5 per pixel, 
per 1-sec image
Revolutionary scientific 
advances enabled by GDO
• Unparalleled advances in the connection of the 
upper atmosphere to the Sun
• Advances in the influence of waves and tides on 
the upper atmosphere
• The ability to probe the mechanisms that control 
the evolution of planetary atmospheres
GDO provides the first...
• Full near-Earth imagery of the storm and 
circulation systems of the upper atmosphere
• Observations of the ionosphere on a global 
and long-time scale basis with unprecedented 
resolution
• Probe of the mechanisms that control the 
evolution of planetary atmospheres
• Test of our understanding of how the Earth 
is connected to our own star on a global scale
Value Proposition
• Provides revolutionary observations of geospace 
required for scientific understanding the coupled 
Sun-Earth System—the key theme of the 2012 
Solar and Space Physics Decadal Survey
• Serves the nation by enabling predictive space 
weather capability for the near-Earth space 
environment where the nation’s space assets 
and ground systems reside and are impacted
Launch 
Vehicle: 
Atlas V 551
Star Motor 
Kick Stage
The real voyage of discovery 
consists not in seeking new 
landscapes, but in having new eyes. 
 —Marcel Proust, 1871–1922
Solar Panel (2)
Antenna
ACS Thrusters
Orbiter Avionics Batteries
Momentum 
Wheels (6)
Hydrazine Tank (2)
Star Tracker
15:37:05
WFoV 2.4m Scale: 25.00
Positions: 1-2
PJR  14-Aug-13 
1.00    MM   
15:30:55
WFoV 2.4m Scale: 25.00
Positions: 3-4
PJR  14-Aug-13 
XZ1.00    MM   
Half of 1-degree-
diameter disk
0.25 degree 
radial, ~180 
degree extent 
annulus
UV/Optical/IR Space Telescopes & Instruments: 
Innovative Technologies and Concepts VI 
Paper 8860–40
James F. Spann, NASA Marshall Space Flight Center, jim.spann@nasa.gov
Patrick J. Reardon, Kenneth Pitalo, The Univ. of Alabama in Huntsville
H. Philip Stahl, Randall C. Hopkins, NASA Marshall Space Flight Center
National Aeronautics and 
Space Administration
www.nasa.gov
G–24084
https://ntrs.nasa.gov/search.jsp?R=20140003223 2019-08-29T14:48:57+00:00Z


The Geospace Dynamics Observatory (GDO) A Paradigm-changing Geospace Mission

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