The GRACE Operations Status depends on the health of the battery and the duration within each orbit when the battery is in use. The Status will be updated here approximately every week.

CURRENT STATUS:

Science Instrument Status:
• All science instruments are operational since May 5, 2016


beta_prime: -47 deg; Altitude: 356.8 km; Separation: 203 km

PEAK beta_prime = -66 deg on July 4, 2016
NEXT beta_prime = 0 event on Sep 22, 2016
PEAK beta_prime = 66 deg on Dec 8, 2016

SCIENCE DATA PRODUCTS:

• 2016
• Jan-2016 Level-2 product delivered
• Feb-2016 Level-2 product delivered
• Mar-2016 Level-2 product delivered
• Apr 01, 2016 to May 05, 2016 - partial L1B data collected
• 2015: Level-2 and Level-1B data products were delivered for every month except the following spans, for which only partial Level-1B data were delivered:
• Dec-08, 2014 to Jan-07, 2015
• Sep-28, 2015 to Dec 10, 2015
• 2014: Level-2 and Level-1B data products were delivered for every month except for the following spans, for which only partial Level-1B data were delivered:
• Jan-18 to Mar-02
• Jun-25 to Jul-30
• Dec-08 to to Jan-07, 2015
• 2013: Level-2 and Level-1B data products were delivered for every month except for the following spans, for which only partial Level-1B data were delivered:
• Feb 27 to April 10, 2013 [Level-2 product for March was not delivered]
• Aug 05 to Sep 24, 2013 [Level-2 products for August & September were not delivered]
• 2012: Level-2 and Level-1B data products were delivered for every month except the following spans, for which only partial Level-1B data were delivered:
• Apr-20 to May-31, 2012
• Sep-26 to Nov-05, 2012
• 2011: Level-2 and Level-1B data products were delivered for every month except the following spans, for which only partial Level-1B data were delivered:
  • Jan-01 to Feb-06, 2011
  • Jun-01 to Jul-06, 2011
  • Nov-17 to Dec-12, 2011

BACKGROUND:

The GRACE Science Operations concept for the remainder of the mission is driven by the intersection of two factors. First is the project decision to operate the spacecrafts in a manner that maximizes the remaining lifetime, so that the longest possible climate data record is available from GRACE. The second is the degraded battery capacity that limits the availability of the power in certain orbital configurations.

The GRACE orbit plane precesses at -1.117 degrees/day relative to the Sun, such that the Sun is in the orbit plane every 161 days. Due to the power system status and desire for longevity, this event will henceforth define a 161-day work cycle for science operations. As long as the beta_prime angle (angle between the orbit plane and the Earth-Sun line) is greater than 69 degrees, the satellite operates using power only from its solar array. For smaller beta_prime angles, the satellites operates partly using the arrays, and partly using the battery. When beta_prime is near zero (i.e. Sun is in the orbit plane), the battery may be used for as much a 40 minutes out of 90 minutes in each orbit. Near beta_prime=0 events, the mission operations status depends on the battery health and operating environment.

This Status will be updated here approximately every week.