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The past two months have seen sparse updates to my Space Flight Log. This is due to a major revision I have been running on the entire system.

Shortly after Christmas, I purchased a new monitor, a 49-inch curved display which allowed me to spread out the Log’s spreadsheets to where I could expand the thing horizontally.

The width of the Log’s sheets has always been limited by my desire to keep from scrolling horizontally while viewing a sheet. This has been further limited by my aging vision; I routinely run my displays scaled up to 125% of normal. The 49” monitor is no taller than its predecessors but is wonderfully wide, and its curvature makes it easy to look at the far edges.

Last summer, I attempted to add information on nationality of payloads and simple orbit parameters, placing them in the Remarks column. This was messy to read, even for me. Furthermore, I had a column labeled “Status” which also included the spacecraft’s decay date.

With the new monitor, I had plenty of room to add new columns. Specifically, I inserted columns for the two customary ID tags for payloads (COSPAR and NORAD), one for nationality of payload (often different from nationality of launch site), one for duration in orbit, and four for simple orbit parameters. I also split my Status column into Status and End Date.

The current list of columns is:

Launch Info:                           Designation

Launch Info:                           Launch Date

Launch Info:                           Launch Nation

Launch Info:                           Launch Vehicle

Launch Info:                           Launch Site

Launch Info:                           # of payloads in the launch

Payload Characteristics:         Name

Payload Characteristics:         COSPAR ID

Payload Characteristics:         NORAD ID

Payload Characteristics:         Nation

Payload Characteristics:         Mission

Payload Characteristics:         Mass

Payload Characteristics:         Status

Payload Characteristics:         End Date

Payload Characteristics:         Duration

Payload Characteristics:         Remarks

Orbit Data:                              Class

Orbit Data:                              Periapsis

Orbit Data:                              Inclination

Orbit Data:                              Period

Launch nation is, as always in my Log, the nation from which the mission was launched. In the case of sea and air launched rockets, this is the nationality of the owner and/or operator of the aircraft or sea launch platform.

The ID tags have been standard since the days of Sputnik and Vanguard.

Mass is always in kilograms.

End Date is the date on which the payload ended its flight through the sky. Occasionally, this is “Destroyed,” which means the craft broke into pieces while in orbit, whether accidentally or intentionally.

Duration is the number of days between the Launch Date and the End Date. When these are the same date, this number is zero.

Remarks have been trimmed considerably, since nationality and orbit have been placed elsewhere.

I moved Orbit Class over to Orbit Data, where it belongs. I kept this as a shorthand key, as I find it useful.

Periapsis and Apoapsis are the generic terms for the highest and lowest points of an orbit. I use them for simplicity. Technically speaking, perigee and apogee only refer to orbits around Earth—and there are a bunch of terms for these quantities when the Moon, the Sun, Mars, etc. are the primary body. Everyone agrees on perihelion and aphelion for solar orbits, but I’ve noticed at least four different pairs of terms for lunar ones.

I always use kilometers for periapsis and apoapsis, except when the orbit is solar, in which case I express it in astronomical units (1 AU=the mean distance between Earth and the Sun, or 149,597,870.7 km). Solar orbits of space probes aren’t always known, and for transfer orbits between Earth and another body they are often temporary and sometimes subject to change due to midcourse power maneuvers or close encounters with another planet (including, naturally, landings and impacts). There are five interplanetary probes which don’t orbit the Sun at all: Pioneer 10, Pioneer 11, both Voyagers, and New Horizons. All of these are on solar system escape trajectories. Properly speaking, they can be considered to orbit the center of the Milky Way, although I don’t think anyone has computed their orbits around our galaxy’s central black hole. Most likely, there should be little difference between those orbits and that of the Sun.

Period is usually expressed in minutes. For Earth orbits, when the period is significantly longer than one day, I also express it in solar days (1440 minutes).

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