50,000 LRO orbits
Erwan MazaricoThe Lunar Reconnaissance Orbiter completed its 50,000th orbit around the Moon on August 1st, 2020 !
Launched on 19 June 2009, it inserted into orbit on June 23 2009. With a period just under two hours, it took more than 11 years to achieve this milestone.
Whether you are just curious about the orbit evolution over that time period or the geometry relevant to observations from any of its 7 scientific instruments, we compiled a large table of parameter values for these 50,000 orbits that would answer many requests.
While it is of course possible to get more fidelity or more specific information by using the LRO SPICE kernels directly (see here and here), through the NAIF toolkit or the online WebGeoCalc tool, we hope this table proves useful for the ‘easier’ queries.
- Periapsis & Apoapsis Altitude vs. Time
The table is provided as a CSV (comma-separated values) ASCII file with one header line and 50,000 records, each with 70 parameters/values. These are detailed below.
==> Download the 34MB CSV file here. <==
Column Number | Parameter Name | Description | Unit | Parameter Block |
01 | OrbitNumber | Orbit Number | - | |
02 | OrbitSMA | Orbit semi-major axis | km | Orbit Keplerian Elements (osculating at ascending node) |
03 | OrbitEcc | Orbit eccentricity | - | |
04 | OrbitInc | Orbit inclination | degrees | |
05 | OrbitLonAscNode | Orbit longitude of ascending node | degrees | |
06 | OrbitArgPeri | Orbit argument of periapsis | degrees | |
07 | OrbitMeanAnom | Orbit mean anomaly (at ascending node) | degrees | |
08 | OrbitPeriod | Orbit period | seconds | |
09 | OrbitNormal_RAj2000 | Inertial right ascension of orbit normal | degrees | Orbit Normal |
10 | OrbitNormal_DECj2000 | Inertial declination of orbit normal | degrees | |
11 | ET_AscNode | Time of ascending node | seconds | Position at ascending node |
12 | Lon_AscNode | Longitude of ascending node | degrees | |
13 | Rad_AscNode | Radius at ascending node | km | |
14 | ET_DescNode | Time of descending node | seconds | Position at descending node |
15 | Lon_DescNode | Longitude of descending node | degrees | |
16 | Rad_DescNode | Radius at descending node | km | |
17 | ET_Peri | Time of periapsis | seconds | Position at periapsis |
18 | Lon_Peri | Longitude of periapsis | degrees | |
19 | Lat_Peri | Latitude at periapsis | degrees | |
20 | Rad_Peri | Radius at periapsis | km | |
21 | ET_Apo | Time of apoapsis | seconds | Position at apoapsis |
22 | Lon_Apo | Longitude of apoapsis | degrees | |
23 | Lat_Apo | Latitude at apoapsis | degrees | |
24 | Rad_Apo | Radius at apoapsis | km | |
25 | ET_Northern | Time of northernmost point | seconds | Northernmost position |
26 | Lon_Northern | Longitude of northernmost point | degrees | |
27 | Lat Northern | Latitude at northernmost point | degrees | |
28 | Rad_Northern | Radius at northernmost point | km | |
29 | ET_Southern | Time of southernmost point | seconds | Southernmost positioin |
30 | Lon_Southern | Longitude of southernmost point | degrees | |
31 | Lat_Southern | Latitude at southernmost point | degrees | |
32 | Rad_Southern | Radius at southernmost point | km | |
33 | Lon_Sun | Longitude of Sun | degrees | Sun geometry (at the time of ascending node) |
34 | Lat_Sun | Latitude of Sun | degrees | |
35 | Rad_Sun | Distance to Sun | km | |
36 | LST | Local Solar Time | Hours (0-24) | |
37 | BetaAngle | Angle between orbit normal and Sun direction | degrees | |
38 | Lon_Earth | Longitude of Earth | degrees | Earth geometry (at the time of ascending node) |
39 | Lat_Earth | Latitude of Earth | degrees | |
40 | Rad_Earth | Distance to Earth | km | |
41 | MeanAnomMoon | Mean anomaly of the Moon in its orbit around Earth | degrees | |
42 | AlphaAngle | Angle between orbit normal and Earth direction | degrees | |
43 | Duration_FullSun | Total duration during orbit when LRO sees the full Sun | seconds | Solar Illumination |
44 | Duration_PartialSun | Total duration during orbit when LRO sees the Sun (even partially) | seconds | |
45 | Duration_NoSun | Total duration during orbit when LRO sees no Sun at all | seconds | |
46 | Duration_ObscuredSun | Total duration during orbit when LRO does not see the full Sun | seconds | |
47 | ET_IngressSun | Time (mid-point) of ingress occultation of the Sun | seconds | Sun Ingress Occultatioin |
48 | Duration_IngressSun | Duration of ingress occultation of the Sun | seconds | |
49 | Lon_IngressSun | Longitude of LRO at (mid-point) of ingress occultation of the Sun | degrees | |
50 | Lat_IngressSun | Latitude of LRO at (mid-point) of ingress occultation of the Sun | degrees | |
51 | Rad_IngressSun | Radius of LRO at (mid-point) of ingress occultation of the Sun | km | |
52 | ET_EgressSun | Time (mid-point) of egress occultation of the Sun | seconds | Sun Egress Occultatioin |
53 | Duration_EgressSun | Duration of egress occultation of the Sun | seconds | |
54 | Lon_EgressSun | Longitude of LRO at (mid-point) of egress occultation of the Sun | degrees | |
55 | Lat_EgressSun | Latitude of LRO at (mid-point) of egress occultation of the Sun | degrees | |
56 | Rad_EgressSun | Radius of LRO at (mid-point) of egress occultation of the Sun | km | |
57 | Duration_FullEarth | Total duration during orbit when LRO sees the full Earth | seconds | Earth Visibility |
58 | Duration_PartialEarth | Total duration during orbit when LRO sees the Earth (even partially) | seconds | |
59 | Duration_NoEarth | Total duration during orbit when LRO sees no Earth at all | seconds | |
60 | Duration_ObscuredEarth | Total duration during orbit when LRO does not see the full Sun | seconds | |
61 | ET_IngressEarth | Time (mid-point) of egress occultation of the Earth | seconds | Earth Ingress Occultatioin |
62 | Duration_IngressEarth | Duration of egress occultation of the Earth | seconds | |
63 | Lon_IngressEarth | Longitude of LRO at (mid-point) of egress occultation of the Earth | degrees | |
64 | Lat_IngressEarth | Latitude of LRO at (mid-point) of ingress occultation of the Earth | degrees | |
65 | Rad_IngressEarth | Radius of LRO at (mid-point) of ingress occultation of the Earth | km | |
66 | ET_EgressEarth | Time (mid-point) of egress occultation of the Earth | seconds | Earth Egress Occultatioin |
67 | Duration_EgressEarth | Duration of egress occultation of the Earth | seconds | |
68 | Lon_EgressEarth | Longitude of LRO at (mid-point) of egress occultation of the Earth | degrees | |
69 | Lat_EgressEarth | Latitude of LRO at (mid-point) of egress occultation of the Earth | degrees | |
70 | Rad_EgressEarth | Radius of LRO at (mid-point) of egress occultation of the Earth | km |
Notes:
- an orbit is defined as starting at the ascending node (i.e., at equator crossing with latitude increasing).
- the times are given as Ephemeris Time (seconds since January 1, 2000, at 12:00 TT).
- longitudes and latitudes are given in the Moon-fixed frame (MOON_ME).