Survey history

Pre-Programmed Pointing Lists

The Pre-Programmed Pointing Lists (PPL) are made by Planck Science Office from the Baseline Scanning Strategy with the help of the Software Planning and Performance Tool. They are sent to MOC/FD for use in making the Augmented Pre-Programmed Pointing Lists (APPL) used for commanding the spacecraft attitude.

The PPL file name is the following: YYYYMMDD_yyyymmdd_NNNN_X.PPL

with YYYYMMDD = start date of the valid span of the PPL file

yyyymmdd = end date of the valid span of the PPL file

NNNN = unique sequence number, in the range 0000 ≤ NNNN ≤ 9999, incrementing sequentially throughout the mission and uniquely identifying each new PPL file that is generated (i.e. no repeated numbers and no gaps in the sequence of PPLs) o 0000-8999 reserved for PSO o 9000-9999 reserved for attitude manoeuvres generated by MOC

X = type of PPL, as follows: o R = Routine (standard 4-week PPL) o C = Contingency (3-day replanning) o L = Long-Term PPL (LTPPL) o S = Special

PPLs contain the following information in ASCII columns:

• pointing reference number

• Ecliptic longitude

• Ecliptic latitude

• nominal start time for pointing

• earliest allowed start time

• latest allowed start time

• nominal dwell time

• observation type

• comments

PPLs can be found in the Planck Legacy Archive.

Augmented Pre-Programmed Pointing Lists

APPLs are made by MOC / Flight Dynamics using pointing information (PPLs) from the Planck Science Office.

The APPLs incorporate information about the Operational Days boundaries in order to fit pointings into each OD.

Attitude History Files

The pointing history of Planck is described in the Attitude History Files (AHF) sequence. All the AHF can be found in the Planck Legacy Archive, for three different methods of computation (AHF, DHF, GHF).

The GHF are made using refined pointing information from the Fiber Optics Gyroscope.

The AHF contain the following information ordered in columns:

Focal plane geometry

The Spacecraft-Instrument Alignment Matrix contains the information.....

Orbit file

The orbit file is produced by the Flight Dynamics team at ESOC and contains the information of the Planck orbital history throughout the whole mission (since launch).

Planck operational state history

he Planck Operational State History (POSH) provides an easily accessible summary of the status of the Planck spacecraft, throughout the course of its mission. It should be useful to scientists as a complement to the data they are analyzing.

Due to the type and quantity of data that describes the state of a satellite and its instruments, it is common for it to be spread over a large number of files and formats which may have to be retrieved from a large number of systems. In addition there are a significant number of potentially interesting occurrences during the mission which are not found in any one single repository; examples are mission milestones, definitions of operational days and anomalous events. The initial motivation for the creation of the POSH was to provide the state of the spacecraft and its instruments in an easily accessible way at any given time. States to be included were the operational phases and the operational status/mode of each of the major payload components. The intention being that this information could be used to assist not only in the operational work in monitoring the status of the survey but also as a data source that could be consulted whilst analyzing science data.

Two main record types are stored in the POSH:

EVENTS, consisting of occurrences during the mission that can be described by a start and end time (e.g. survey boundaries, anomalies, ODs, manoeuvres). The definition of an event is provided for operational purposes; it may or may not agree with the definition of an event for data analysis purposes (e.g. the boundaries of a survey may be defined in a different way in the pipeline).

HOUSE KEEPING (HK) SUMMARY which consists of some HK timelines with one data point per pointing period (e.g. temperatures, position in the sky, drift rates, sun angles). This data set contains a very compact operational summary of the mission (not an exhaustive list of HK).