Over the past two months, I’ve expanded the orbital data to include every launch up to the end of June 2023. The orbit parameters are included with the Remarks, with an explanation at the bottom of each year’s sheet (it’s at the bottom of the Key).
I couldn’t get all of them. Several payloads were so secret that the orbital info has always been unavailable. There have been a few which decayed too quickly to be tracked by Spacetrack or by anyone else. I have intentionally omitted orbital data for many deep space probes, particularly those which made direct ascents to land on/impact with another celestial body such as Mars, Venus, or the Moon. Likewise, the five probes which have escaped the Solar System (Pioneers 10 & 11, both Voyagers, and New Horizons) have no orbital elements. They are now in orbit around the center of the Galaxy.
I intend to add orbital data for new launches every quarter or so. Many comsat orbits as given by Spacetrack or Jonathan McDowell are not necessarily the final operating orbits, as most geostationary birds spend a few days to a few weeks in something resembling Molniya orbits before settling down on station. Members of LEO com constellations such as One Web and Starlink often take one to three months to reach station, as they rely upon tiny, continuous boosting from small ion thrusters using a noble gas such as xenon or argon to attain their stations.
From time to time, I may insert new orbital data on very old satellites which remain in orbit (probably from 1975 and earlier). This won’t happen often, perhaps annually. Those old birds are in very stable orbits which experience very little atmospheric drag.
The following notes about orbits are taken from the Key found on all sheets:
Orbital parameters in Remarks:
Format: Perigee (km)-Apogee (km)-Inclination (degrees)-Period (minutes).
Spacetrack: Source of current orbits at epoch 2023-05-06, launch dates thru Dec. 2022.
RAE Tables & TRW Space Log tables: Initial orbit parameters for all satellites 1957-2008.
McDowell master list: Initial orbit parameters for decayed satellites Nov 2008 thru Dec 2022.
Spacetrack and McDowell: Source for new orbits 2023-onward.
Spacetrack and McDowell: Source for occasional updates of most orbits active >40 years.
When no parameters are found, other sources will be used (and cited) if available. Sometimes, orbital parameters are just plain unavailable. I note where this happens. Large, high-drag objects at perigee~420 km such as ISS require frequent boosts to maintain orbit. Payloads at perigee <500 km will experience appreciable drag. Initial operating orbits should give a rough idea of a payload’s future orbital lifetime. Don’t expect anything with perigee <300km to stay around very long. Exception: Sats inserted into low initial orbits which maneuver higher (e.g., Starlink). Solar orbits are usually expressed in astronomical units, inclination to ecliptic, and days or years.
As for routine updates, I tend to post those once or twice a week unless I’m taking a vacation or otherwise offline for a while. When updating the manifests of future launches, I don’t always update everything, just the month or two closest to the current date. Once every month or so, I update the future manifest for the current year, and those of future years every few months.
I update the Box Score file annually. The current year does not appear in the Box Score until it is ended. If I have to edit the earlier years, almost always to correct a minor error, I repost the Box Score with days of the correction.
I hope you enjoy my Space Flight Log and find the info you want from it.
Clear ether,
Jeanne Jackson