Cluster Spacecraft Identifiers
This page provides a cross-reference table for the various identifiers used to describe the four
Cluster spacecraft. Please send any requests for changes to
Mike Hapgood.
The table also includes the guidelines agreed by the Cluster Science Working
Team for plotting data from the four Cluster spacecraft.
The use of these guidelines is not mandatory. But it will make data analysis
and comparison much easier if everyone uses the same convention.
| ESA Name | | Rumba | Salsa | Samba | Tango |
| Launch date | | 9 Aug 2000 | 16 Jul 2000 | 16 Jul 2000 | 9 Aug 2000 |
| ESA Number | | 1 | 2 | 3 | 4 |
| COSPAR ID | | 2000-045A | 2000-041B | 2000-041A | 2000-045B |
| USSPACECOM catalogue number* | | 26463 | 26464 | 26410 | 26411 |
| CSDS Code | | C1 | C2 | C3 | C4 |
| ESOC FD code | | S1 | S2 | S3 | S4 |
| ESA Flight Model number | | FM5 | FM6 | FM7 | FM8 |
| | | | | | |
| Plotting guidelines |
| | | | |
| Colour | | Black | Red | Green | Magenta |
| Line Style | | Solid | Dashed | Dotted | Dash-dot-dot-dot |
| Symbols | | Cross | Plus | Asterisk | Star |
| or | | Square | Diamond | Circle | Triangle |
| ESOC planning |
| | | | |
| Colour | | Red | Yellow | Blue | Green |
*IMPORTANT: The USSPACECOM catalogue numbers for Cluster 2 and 4 are the reverse of what would be expected
on the basis of launch date, i.e. C2 should be catalogue number 26411 and C4 should be 26464.
However, examination of the perigee times derived from USSPACECOM two-line elements confirms the catalogue
numbers above. Note also that the Cluster spacecraft descriptions in the USSPACECOM catalogue are incorrect;
see above for correct descriptions.
Notes
ESA Number. This is the spacecraft id used in Cluster operations by ESOC and JSOC.
COSPAR ID (also known as the International Designation). This id is assigned by World Data Center A for Rockets
and Satellites at NASA Goddard Space Flight Center following spacecraft launch. It is the unique designator that is
required for all spacecraft under international law. It takes the form YYYY-LLLI, where YYYY is the year of launch,
LLL is the launch number and I is a letter that distinguish the different items launched.
USSPACECOM catalogue number (also known as the NORAD catalogue number). This is the catalogue number assigned by
NORAD when an object is first tracked.
CSDS code. This is the two-character spacecraft code used in the data products
produced by the Cluster Science Data System (CSDS).
ESOC FD Code. This is the two-character spacecraft code used in the names of
orbit and event files produced by ESOC Flight Dynamics.
ESA Flight Model number. These are the numbers used by ESA during the construction and ground testing of the Cluster-II spacecraft. Note that this sequence follows on from that used for the construction and ground testing of the original
Cluster-I spacecraft.
Symbols. The first set of symbols are made out of line segments, whereas
the second set may be either outlines or solid-filled.
Note that asterisks have 6 legs and stars have 5 points.
ESOC planning. These are the colours used by the ESOC Mission Planning System, e.g. to plot SSR fill.
Other spacecraft linked to Cluster
USSPACECOM
catalogue number |
COSPAR ID |
Description |
| 26106 | 2000-015A |
This object is shown as FREGAT RB/CLUSTER 2 in the USSPACECOM
catalogue. It is thought to be one of the test versions of the Fregat upper stage that was flown
before the main Cluster launches. It remains in orbit in 2008 as its perigee is around 400km. |
| 26412 | 2000-041C |
This is the Fregat upper stage from the first Cluster launch. It
was intentionally de-orbited and decayed within a few hours of the launch. |
| 26465 | 2000-045C |
This is the Fregat upper stage from the second Cluster launch. It
was intentionally de-orbited and decayed within a few hours of the launch. |
Comparision of TLE data with definitive data from ESOC
To verify the USSPACECOM catalogue numbers of the Cluster spacecraft, we have compared perigee times from
the two-line elements (TLE) with with the definitive times in the Cluster event files provided by ESOC.
We take the TLE perigee time as Tp = Te - k*MA/R, where Te is the epoch time,
MA is the mean anomaly at the epoch, R the revolution rate and k is the constant to match units of the
different elements; k= 1/360 if MA is in degrees, Tp and Te in days and R is in revolutions per day.
To facilitate a comparison across the whole period of the Cluster mission, we calculate offsets from
the ESOC perigee time for Cluster 1. The four plots below show the offsets for ESOC and TLE perigee times
of Cluster 1, 2, 3 and 4 using the above mapping of USSPACECOM catalogue numbers. The ESOC perigee offset is shown as
a solid green curve, whilst the TLE offsets are shown as red dots. You can see that there is
generally a good match away from manoeuvres, i.e. on the slowly varying parts of the curves. Indeed the green curve
in these parts is often hidden by the red dots. This match confirms the mapping of USSPACECOM catalogue numbers.
But near manoeuvres, i.e. the rapidly varying parts of the curves, the TLE perigees are often marked different
from the definitive ESOC values. There are many cases where the TLE data continue the previous trend of Cluster
perigees and there is some delay in picking up new trends after manoeuvres. These differences indicate that the
TLE data may be significantly in error, especially around manoeuvres. Thus it is strongly recommended to use ESOC
orbit data, and avoid use of TLE data, in support of Cluster science analysis. If TLE data must be used (e.g.
because required by software tools) its use should restricted to periods away from manoeuvres.
Last updated by Mike
Hapgood ( mike.hapgood@stfc.ac.uk),
27 September 2008
(email links updated 27 November 2017)
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