50,000 LRO orbits

Erwan Mazarico

The 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.


The following links are to interactive plots that allow identifying time periods that match several kinds of geometry constraints. For more complex filtering, the full CSV table should be used.

- Orbit Number vs. Time

Periapsis & Apoapsis Altitude vs. Time

Periapsis Latitude vs. Time

Earth (alpha) and Sun (beta) aspect angles vs. Time

Orbit Inclination vs. Time

Orbit Semi-Major Axis vs. Time

Orbit Period vs. Time

Argument of Periapsis vs. Time

Moon Mean Anomaly vs. Time

Latitude of Earth Occultations vs. Time

Duration of Earth Occultations 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).

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