If the satellite is UN registered (a registration document is noted
in the appropriate field) but no name was given in that registration, I enclose the name used
in square parentheses to indicate that it's not official. For example,
for object S01328, the UNReg field contains
"A/AC.105/INF.107", indicating that the satellite is registered. The name is given as
"[Explorer 27]", the square brackets indicating that no name was actually given in the registration
document.
As with other UN registration metadata reproduced here, the UN name data
are provided so you can compare UN registration information with the
primary information in the catalog. In this instance, the name in the
object catalog (or even better, in the unicode name list) is generally
to be preferred over the name given here.
The date on which the satellite was most recently known (by me) to be active. Often, it's hard
to find out whether a satellite is still operating, especially if it does not actively
control its orbit. It is therefore helpful to know if it's been known to be active
fairly recently, or whether there has been no news of it for decades. Caveat: I only
update this infrequently and patchily. The fact that *I* haven't heard news of the satellite operating
since 2006 doesn't mean that obvious evidence of its continued activity doesn't exist.
Vague Date Format is used to record the value.
An asterisk in this field indicates that no information is available.
The date on which the satellite is believed to have completed regular operations. This is a loosely
defined concept. The idea is that after this date the satellite may have been used for on-orbit tests
and training, or may still have had an active radio beacon, but was not in use for its primary purpose.
(That's not the same as `end of primary mission', which can be much earlier).
Vague Date Format is used to record the value.
An asterisk in this field indicates that the payload is believed to be still
operating.
I also refer to this as the "Dead, Dead, Dead" date - it is
the date after which the satellite became completely silent and unresponsive, or when
no further contact was made by its owners. I prefer to use this
as an end-of-life date. (There is some ambiguity here. Some old satellites are abandoned by
their owners but still emit a radio beacon.)
Vague Date Format is used to record the value.
An asterisk in this field indicates that the payload is believed to be
still transmitting.
| Value | Meaning |
|---|---|
| D | Recovery capsule which spent a matter of seconds as a separate orbiting object before the deorbit burn. |
| E | Deep space mission, may be operating outside Earth orbit. |
| U | This satellite is thought to be still working but the UCS active satellite list suggests it is not. |
| X | Satellite end of life date is a guess and satellite could still be partly operating. |
| Z | Zombie satellite: no longer controlled, but continues emitting a beacon signal. |
The field describes the type of attitude control. However, values of this field
have not yet been systematically filled in.
| Value | Meaning |
|---|---|
| - | Unknown |
| G | Gravity gradient stabilized |
| P | Pointed, 3-axis stabilized |
| PS | Sun pointed |
| PN or N | Nadir (Earth) pointed |
| S | Spin stabilized |
| U | Unstabilized |
This field indicates whether the satellite has or had a propulsion system
capable of changing its orbit. Valid nonempty values are 'M', indicating
that the satellite is manueverable, and 'D', indicating that the
satellite's propulsion system is capable of a single burn to deorbit
the satellite.
| Value | Meaning |
|---|---|
| A | Amateur/academic/non-profit |
| B | Business (commercial) |
| C | Civil (government but not military) |
| D | Defense (govt. military, intelligence) |
Two-letter combinations of these have the obvious meaning:
e.g. BD means a satellite which has both commercial and military use.
In general, I find the concept of `dual-use' to be mostly unhelpful.
Almost everything is potentially usable for military purposes, but
almost everything is nevertheless fairly clearly assignable
to one of the above four principal uses. I only
use the dual-use two-letter characterization for 16 (as of 2020)
satellites in the catalog where the management and operation is clearly
shared between two organizations connected with different class values.
In the case where two values are present,
the values in this
field are concatenated with a slash between them - for example 'IMG/TECH'.
Uncertain categories have an appended question-mark.
An asterisk appended to the category indicates that the orbital data
for the satellite are (or formerly were) kept secret by the US government.
The defined categories are:
| Value | meaning |
|---|---|
| AST | Astronomy |
| BIO | Biology and life sciences |
| CAL | Calibration (for atmospheric density, space surveillance radars, etc). Usually passive. |
| COM | Communications |
| EDU | Educational purposes. |
| EOSCI | Earth observing science, except imaging |
| EW | Missile early warning, including ballistic missile defence tracking |
| GEOD | Geodesy |
| IMG | Imaging (optical), except meteorology |
| IMG-R | Imaging (radar) |
| INF | Infrastructure (support structures, deployers etc) |
| MET | Meteorology (imaging) |
| MET-RO | Meteorology (radio occultation) |
| MGRAV | Microgravity experiments |
| MISC | Miscellaneous (e.g. burial services) |
| NAV | Navigation, positioning and timing |
| PLAN | Deep space related mission |
| RB | Rocket body (rocket upper stage) |
| RV | Reentry vehicle |
| SCI | Scientific studies, except astronomy and Earth observing |
| SIG | Signals intelligence |
| SS | Spaceship, i..e human spaceflight related (including cargo ships) |
| TARG | Target for missile defense or antisatellite tests |
| TECH | Technology and training |
| WEAPON | Weapon, including antisatellite experiment and FOBS |
| Value | Meaning |
|---|---|
| A | |
| AIS | Automatic ID system (ship tracking) |
| ALT | Radar altimeter |
| ATM | Atmospheric science |
| AUR | Auroral research |
| BIO | Biology and life sciences |
| CR | Cosmic rays |
| ENV | Space enviromental exposure |
| ESCI | Earth sciences |
| F | Electromagnetic fields |
| GEOD | Geodesy |
| GRA | Gamma ray astronomy |
| IMG | Imaging |
| ION | Ionospheric research |
| IRA | Infrared astronomy |
| M | Humans in microgravity and related research |
| MG | Microgravity experiments |
| MM | Micrometeorite studies |
| OA | Optical astronomy |
| P | Particles |
| PHY | Basic physics |
| PL | Planetary science |
| RFA | Radio-frequency astronomy |
| SMA | Submillimeter astronomy |
| SOL | Solar physics |
| SX | Solar X-ray astronomy |
| TECH | Technology experiments |
| UVA | Ultraviolet astronomy |
| XNAV | X-ray navigation |
| XRA | X-ray astronomy |
If the satellite has not been registered with the UN, the field
contains, in square parentheses, the OrgCode string corresponding to the
country which I think *ought* to have registered it. (If this isn't
the same as the owner country in the object catalog, an asterisk is
appended to the closing square parenthesis - e.g. `[US]*').
If the satellite has not been registered, but it's not a `real payload'
(minor subsatellite, etc.) and I don't think it requires registration,
the field is left blank.
An appended asterisk indicates that the online UN site reports that the satellite was registered in a particular
document, but the document isn't yet available on that site, so I can't
see what it actually says! Unfortunately some US registrations have been `in process' for several years now
(as of mid 2020).
A blank entry indicates that the satellite has not been registered with the UN.
Inclusion of the disposal orbit data is currently an experiment and tne data should not be relied upon at present (2024 Oct).