skip to content
HETE-2 Archive

HETE-2 Data Products and Formats

Fregate 4-band Gamma-ray burst lightcurves: These lightcurves were constructed from Fregate data in the 8-40, 8-70, 32-400 & >400 keV bands. The lightcurve files conform to the OGIP Proposed FITS Format for Timing Files. These files are FITS versions of the ASCII rate files (the qdp files) in the GAMMA/FastLook directories (see, for example, the qdp files in

Inter-process Protocol (IPP): Communications among various parts of the HETE (those connected directly or indirectly with the satellite) is accomplished through an inter-process protocol known as IPP. On the ground side, each IPP process ends up as a separate UNIX process that registers with a central router (the CNS) and then hangs around sending and receiving messages as appropriate.

IPP messages are composed of some number of (unsigned) short words (16-bit data quantities 0--65535) partitioned into a 9-word header containing certain general information, and a variable-length data portion. The most interesting header items are:

  • Length: gives the word count (0--512) in the data portion
  • Priority: gives the importance of the messsage (0--63: most--least)
  • Type: speaks to the information content of the message
  • Sequence: a sequential id for messages sent in series
  • Destination: a symbolic process number to which the message is to be sent
  • Source: a symbolic process number which has sent the message
  • Timestamp: a 32-bit quantity indicating when the message was sent (256 µsec ticks of the sender's clock)
The additional header elements indicate whether the message is sent with a checksum (for verifying the message arrived intact) and if so, what the checksum is.

The above information on the IPP data format was taken from the HETE2 Operator's Manual. For more information contact the HETE2 help desk (

These files are automatically stored (at the HEASARC) as follows:


The reference time for each data file is UTC at the start of the pass (YYYY is the year, MM is the month or minute, DD is the day, HH is the hour, SS is the seconds), and key letters P are used to indicate the groundstation.

key groundstation
C Cayenne
K Kwajalein
S Singapore
M MIT data

The file suffix X refers to the file contents using the following key:

suffix Content
u IPP uplink commands to PGS
1 (numeral one) IPP uplink commands sent & acknowledged
2 IPP uplink commands sent & not acknowledged
3 IPP uplink commands not sent
h High priority downlink IPP data
d Middle priority downlink IPP data
l (lowercase L) Low priority downlink IPP data
s PGS status IPP data
c PGS status commentary
v SGS VHF messages
o Raw Duty Operator log commentary

Additionally, the archive contains data regarding communications with the GPS instrument. These files are:
hete2ln-YYYYMMDD-HHMM HETE TLE projections
YYYYMMDD-HH HETE-SUN conjuctions projections
RAL-AA-YYYYMMDD-HH GPS Almanachs (AA = 01..31)
REC-YYYYMMDD-HH Diogenes telecommands
ROR-YYYYMMDD-HH GPS orbit commands

Page Author: Dr. Michael F. Corcoran
Last modified 2003-02-10