1. NASA’s Global-scale Observations of the Limb and Disk (GOLD) Mission: Unprecedented Imaging of the Boundary Between Earth and Space
Richard Eastes
GOLD Mission PI
Laboratory for Atmospheric and Space Physics
University of Colorado

2. GOLD Status Launched on SES-14 - Jan 25, 2018
Ariane 5 rocket from French Guiana
Detector doors opened - Jan 29, 2018
Next Activities
Commissioning in late August 2018
Operations begin October 2018
GOLD Launch (Jan 25th, 2018)

3. The View from Geostationary Orbit
GOES-13
1302 UTC
GOES-13 is at 75° West longitude
Began in 2004, launching 13 years later, more on that later…
Dreaming of the GOLD ultraviolet (UV) imager at GEO since 2004

4. GOLD Mission Overview Host Mission GOLD Instrument Science Data
12/10/2019
GOLD Mission Overview
Host Mission
SES-14, in geostationary orbit over mouth of the Amazon River
GOLD Instrument
Two identical, independent imaging spectrographs
Each observes disk and limb at nm
Science Data
Earth’s disk
Daytime: images of O/N2 (density ratio), temperature
Nighttime: images of peak density in ionosphere
Earth’s limb (edge of Earth)
O2 densities and temperature at top of thermosphere

5. Unique Mission Operation Elements
GOLD Ground Station, Woodbine, MD
GOLD Subsatellite Point
Geostationary orbit, satellite stays over same location
Data transmitted to GOLD ground station in real-time

6. SES-14 Satellite Airbus Defence & Space Eurostar E3000e satellite
Electric propulsion…. Surprise, 4-5 months to reach orbit
Airbus Defence & Space Eurostar E3000e satellite
Design life of 15 years
Ariane 5 launch vehicle
Electric propulsion for orbit transfer and station keeping
Dry mass of ~4.5 metric tons

7. GOLD Mission Imager Spacecraft Deck
Imaging Spectrograph: Two independent, identical channels imaging the limb and disk, and a single processor packaged in one housing
Wavelength range: 132 – 162 nm
Detectors: Microchannel plate, 2-D crossed delay line anode
Channel 2
Channel 1
27”
21.5”
20”
E Box
Spacecraft Deck
6 Kinematic Struts
Resources Summary
Mass
37.0 kg (measured)
Power
60.4 W (CBE, AVG)
Data
6 Mbits/second

8. Forcing of the Thermosphere-Ionosphere
Forcing from Above
Science Question 1 (Q1). How do geomagnetic storms alter the temperature and composition structure of the thermosphere?
Q2. What is the global-scale response of the thermosphere to solar extreme-ultraviolet variability?
Q4. How does the nighttime equatorial ionosphere influence the formation and evolution of equatorial plasma density irregularities?
Thermosphere-
Ionosphere
Science Questions 1-4
Q3. How significant are the effects of atmospheric waves and tides propagating from below on thermospheric temperature structure?
Forcing from Below

9. The Boundary Between Earth and Space
Thermosphere-Ionosphere System – Space Weather
T-I coupled
Similar on other planets
Space weather changes are ~10 times changes in troposphere
These changes affect RF propagation between the Earth and space

10. Solar and Geomagnetic Forcing
Forcing from above; source is familiar; big news if
Knipp et al, 2004

11. Geomagnetic Storm in the Thermosphere-Ionosphere
E-region Electron Density (~110 km)
Neutral Temperature (~160 km)
F-region Electron Density (~300 km)
O/N2 Ratio (~160 km)
Solomon

12. Modeled Tidal Effects at Lower Altitudes
Modeled tides at 100 km: some of these tides propagate to higher altitudes. Even for tides that do not reach 160 km, may have effects there.
D – diurnal
E, W, S – direction
1, 2, 3 – wavenumber
zonalwind_100km_tuv_hme_fit_dw2_to_de3_sep_2005.avi
Movie to play for this slide
Effects of nonmigrating tides may reach 160 km even if they do not.
What we know is based on long term sums of data
J. Oberheide/Clemson

13. Modeling of Gravity Waves from Typhoon
155 K
225 K
T (K) at ~110 km
(near upper boundary of the model)
From: Hanli Liu at NCAR/HAO
Longitude
Latitude

14. Modeling Thermosphere-Ionosphere With and Without Lower Atmosphere Variability:
Coupling to the chaotic lower atmosphere introduces a fuller spectrum of variability
Independent of lower atmosphere:
Coupled to lower atmosphere:
Global maps show little structure
Global maps show structure relevant to
GPS accuracy and availability
HF Comm.
24 February 2015
R. Viereck/NOAA

15. GOLD’s Observing Scenario and Data Products
Full disk images and limb scans with 30 minute cadence
Dayside data products: Disk temperature, Disk O/N2, OI and N2 emission brightness, TEXO, QEUV
Nightside products: Disk OI brightness, crest locations, Nmax
Occultation measurements
Dayside and nightside products: O2 density profile

16. GOLD Imaging - Simulated GOLD image of oxygen (135.6 nm) emissions
S. C. Solomon/HAO
Right: spectral image in wavelength and angle along slit.
S. C. Solomon
- Simulated GOLD image of oxygen (135.6 nm) emissions
- Simultaneously images N2 emissions on dayside
- Emissions provide key data for thermosphere and ionosphere

17. Important Benefits to Science and Society
Advance Heliophysics science by linking solar observations to thermosphere-ionosphere physics
Develop the next generation of upper-atmosphere models
Address operational challenges in space-based communication, GPS navigation, and orbital tracking
Engage the public by providing near-real-time global images of aurora and space weather

18. GOLD Mission Summary & Status
• Launched on Jan. 25, 2018 • GOLD will image space environment response to forcing from above and below • Simultaneous disk images of thermospheric composition and temperature • Can separate changes in time from changes in location • Provides context for ground-based and LEO observations, e.g. ICON mission • Two years of mission operations scheduled to begin Oct. 2018