National Aeronautics and Space Administration

How Much X-Ray and Gamma-ray Data Are in the HEASARC's Archive?

Last Update: 2018 February

As of this date, there were about 100 Terabytes (TB = 1 billion kB) of X-ray and gamma-ray data in the HEASARC's high-energy archive, compared to 85 TB in February 2017, 38 TB in April 2012, 1.8 TB at the start of 2000 and 0.3 TB at the start of 1995. Growth in the last 6 years has been mostly due to the increasing size of the Swift (now 28.5 TB), Fermi (now 20.1 TB), INTEGRAL (now 14.8 TB), and XMM-Newton (now 8.8 TB). Other HEASARC missions which are currently being archived include the NICER (now 3.6 TB), Chandra (now 2.6 TB) and NuSTAR (now 1.8 TB) missions. Data volumes from previous missions are typically much smaller: Hitomi (0.76 TB), RXTE (2.7 TB) and BeppoSAX (1.3 TB), except for the Suzaku (11.1 TB) mission.

For more detailed statistics, including a breakdown of the data holdings by mission, check out the HEASARC Usage Statistics webpage.

figFigure 1: Growth of the HEASARC High-Energy Data Archive and Annual Volume Downloaded by Users.

    Start       Archive Size    Archive Growth     Number of Active High-Energy          Major
   of Year      in TB           Rate in TB               HEASARC Missions                Events

     1993          0.001                 0.001                 4       Launch of ASCA, joining EUVE, ROSAT & CGRO
     1994          0.014                 0.013                 4
     1995          0.30                   0.29                 5       Launch of RXTE

     1996          0.45                   0.15                 6       Launch of BeppoSAX
     1997          0.55                   0.10                 6
     1998          0.96                   0.41                 6
     1999          1.37                   0.41                 7       Launch of Chandra & XMM; End of ROSAT
     2000          1.84                   0.47                 5       End of CGRO & ASCA

     2001          2.13                   0.29                 5       Launch of HETE2; End of EUVE
     2002          2.52                   0.39                 5       Launch of Integral; End of BeppoSAX
     2003          2.85                   0.33                 5 
     2004          3.12                   0.27                 6       Launch of Swift
     2005          4.84                   1.72                 7       Launch of Suzaku

     2006          8.27                   3.43                 7 
     2007         11.90                   3.63                 6       End of HETE2
     2008         17.09                   5.19                 7       Launch of Fermi
     2009         19.88                   2.79                 7
     2010         25.79                   5.91                 7

     2011         30.66                   4.87                 7
     2012         37.90                   7.24                 7       End of RXTE; Launch of NuSTAR
     2013         43.52                   5.62                 7
     2014         53.52                  10.00                 7
     2015         65.43                  11.91                 7       End of Suzaku

     2016         74.90                   9.47                 7       Launch & End of Hitomi
     2017         84.60                   9.70                 7       Launch of NICER
     2018        100.41                  15.81                 7

Web page author and maintainer: Stephen A. Drake