For each object, the SatType string in the entry for the first phase for that object applies to the whole history of the object. If the type is different in a later phase, that's probably a data entry error.
The byte layout is as follows:
|Byte 1||Coarse Type (payload, rocket, debris)|
|Byte 2||Type modifier|
|Byte 3||Attach flag|
|Byte 5||Orbit flag|
|Byte 6||Human spaceflight subset|
|Byte 7||UN registration flag|
|Byte 8||Failure flag|
|Byte 9||Uncertain ID flag|
|P||Payload (for orbital attempt)|
|R||Launch vehicle stage|
|S||Suborbital payload (e.g. sounding rocket payload or missile reentry vehicle)|
|X||Catalog entry that has been deleted (used in auxcat etc.)|
|Z||Spurious catalog entry (was in SATCAT, perhaps in TLEs, but there was no real object)|
The Byte 2 entries modify the Byte 1 entries (and are not independent of them). Here I tabulate the combined byte 1/2 values and their meanings. (cases where byte 2 is blank are not listed).
|Byte 1-2 Value||Meaning|
|PH||Spaceship with humans aboard at launch.|
|PP or CP||Spaceship with pressurized cabin, but without humans at launch.|
|PX: Not in standard list of satellites.|
|R1 to R5||Stage number for launch vehicle stage.|
|CC||Cargo placeholder for mass accounting.|
|CX||Component not to be included in certain standard lists|
|CD||Deployer for separately integrated payload|
PA: The A (alias) modifier is used for special records representing a phase where the satellite is leased temporarily or jointly owned. This phase type is special in that its time period overlaps another phase. An example is object S23779 (Palapa C1, renamed HGS-3 in Nov 2000) From Dec 2000 to Jan 2003 its capacity was leased to Turk Telecom which called it Anatolia 1. The HGS-3 entry is tagged with SatFlag equal to P (standard payload) while the Anatolia 1 entry covering an overlapping time period is tagged with SatFlag equal to PA to denote that it's a secondary or alias entry that may be ignored.
PP: The P modifier is used for spaceship test flights without crews, pressurized sections of cargo ships, and space station modules.
PX: The X modifier is used to denote `non-standard payloads'. What is a payload and what is just a component? I take a broader view of `payload' than most satellite lists do. Some examples of `PX' types:
CC is used for `down cargo' for space stations returned to Earth or destroyed in cargo ship reentry. Note that we usually don't know the launch date of `down cargo'.
The D modifier (CD) is used for separately integrated deployers. The D flag has been added to reflect the emergence of intermediary companies like Nanoracks and Spaceflight which sit between the payload owner and the launch provider and manage the integration of customer payloads Note that byte 4 has a V value for 'deployer/clamp band' which is more general and does not imply a separate integration - it includes things like the CRRES canisters or the Shuttle PAM-D ASE. (Well, it's an interesting question whether those count as equivalent to a Nanoracks deployer, but I think the hardware and integration were done by NASA - I could be wrong.)
Objects with a D flag in byte 2 are usually not separate satellites but attached to a parent object (e.g. launch vehicle stage). They are therefore usually in the A (auxiliary) catalog.
|Byte 3 Value||Meaning|
|A||Permanently attached component or payload|
|F||Stuck attached by mistake|
|S||Expected to separate in future|
|T||Never flew free but transferred|
F indicates that the object was intended to separate but failed to do so. S denotes that the object is expected to separate at a later date. T is mostly used for hardware that is transferred from the exterior of one object to another during a spacewalk or using robotic arms.
I is used for entries representing hardware that remains internal to one or more host spacecraft, possibly being transferred between them. Entries of this sort that I keep track of include EVA spacesuits not actually used on an EVA; cubesat dispensers used on ISS; and special entries used to do mass accounting of upward and downward space station cargo. In the future I'm considered adding entries for human space travellers, who would also be internal (either to a spaceship or a spacesuit).
|Value||Meaning||Allowed B1 values|
|A||Payload adapter (e.g. SYLDA).||C|
|B||Battery explosion debris||D|
|C||Passive calibration satellites||P, C|
|E||Spacesuit on tethered spacewalk||P (PX)|
|F||Fairings and other covers||C|
|G||General, miscellaneous debris||C, D|
|H||Human spaceflight related||P,C|
|I||Impact (accidental collision)||D|
|J||Anomalous debris (insulation, soft material)||D|
|K||Support structures, interstages||C|
|L||Separated from vehicle after landing (rovers, etc)||P, C|
|M||Jettisoned motor or tank||C|
|N||Nuclear reactor core or coolant blob||C, D|
|O||[not used yet]|
|P||Propulsion related, residual-propellant breakup||D|
|Q||Aerodynamic breakup at low perigee||D|
|S||Subsatellite or subpayload||P|
|T||Ejected section of payload||C|
|U||Untethered EVA||P (PX)|
|V||Ejection mechanism (deploy canister, clamp band)||C|
|W||Weapons test, ASAT debris||D|
|X||Debris of unknown nature||C, D|
|Y||Despin (yo-yo) device||C|
|Z||Breakup debris from on-board destruct device||D|
|E||Destroyed in pad explosion|
|F||Failed to reach orbit|
|X||Missing from SATCAT by mistake (EXPRESS, IXV)|
|L||Active on planet surface during this phase|
|S||Near-Orbit (marginally suborbital)|
|P||Partial orbit - reached legit orbit but deorbited after less than 1 rev|
|T||Transient orbit - separated just (perhaps seconds) before deorbit|
|R||Reentry orbit: objects that were attached and separated in post-deorbit-burn suborbital trajectory|
|O||Orbital-Energy but Non-Orbit|
|D||Deep Space or escape|
|V||Escape energy but not deep space|
|I||ISS program, general|
|C||ISS major non-module component|
|D||ISS deployable subsatellite|
|S||Space Shuttle program or Shuttle payload or component|
|V||ISS visiting vehicle|
|U||Is, or should be, UN registered even though not a standard payload.|
|X||Was UN registered but should not have been.|
For example, object A06499, the Canadarm-2 on the ISS, is not a standard payload and has no SATCAT entry. Nevertheless it was registered with the UN. A05668 Fasat-Alfa was a satellite that failed to separate from its parent satellite. It doesn't have a separate SATCAT number from its parent S23657 Sich-1, so it is a `PX' nonstandard payload; but it was registered by Chile, while Sich-1 was registered by Ukraine. Byte 7 is set to U.
Object A05597 EXPRESS completed several orbits of the Earth. It is a `PX' nonstandard payload because the US tracking system failed to catch it, and it doesn't have a SATCAT number. Nevertheless Germany should have registered it with the UN and did not. Byte 7 is set to U.
On the other hand, A06874 Celestis-04 Error was registered with the UN but should not have been, since it was removed from the rocket before launch and never got to space. Byte 7 is set to X.
Object A07634 ELC-1 is a logistics carrier launched on the Shuttle and later attached to the ISS. Although the US has usually registered ISS pressurized modules, other similar minor ISS components (such as the other ELCs and the major truss segments) have not been registered, so for consistency ELC-1 shouldn't have been registered either. Byte 7 is set to X.
Other values indicate different kinds of payload failure (or success) and have been added to support analysis of the Starlink constellation.
|*||This object was the one that failed during launch.|
|A||Satellite ascending: orbit raising to op orbit (or lowering from high drift orbit)|
|D||Satellite in plane drift orbit|
|F||Satellite failed early in mission, before reaching operational orbit ("screened")|
|L||Satellite removed far from operational constellation by lowering or raising orbit|
|M||Satellite failed in operational orbit and is undergoing uncontrolled decay - non manueverable|
|O||Satellite is active in operational orbit|
|R||Satellite reentered after active orbit lowering|
|S||Satellite was used for special tests outside of main constellation|
|T||Satellite removed slighly (and possibly temporarily) from operational constellation by lowering or raising orbit a little|
|U||Satellite apparently malfunctioning, held in intermediate orbit for debugging?|
|?||The association of this satellite with this catalog number is a guess because JSpOC has not yet assigned a name. ID may change in future.|
|m||Multiple objects. This entry is a placeholder for a known debris event where no debris has yet been cataloged by DoD.|
|C||US government orbital data for this object are secret.|
|U||This object is a cargo item on ISS (or other station) and has been assigned to a likely cargo launch but the actual launch for this object is not known.|
|D||This object is a cargo item on ISS (or other station). The return date is uncertain and I've made a guess at which ship it went down on.|
|X||We don't know which launch this object is from, so the launch date is unknown (and other parameters may also be unknown).|