| Remote Sensing Hands-On Lesson, using TGO (C) |
Table of ContentsRemote Sensing Hands-On Lesson, using TGO (C) Overview Note About HTML Links References Tutorials Required Readings The Permuted Index API Documentation Kernels Used CSPICE Modules Used Time Conversion (convtm) Task Statement Learning Goals Approach Solution Solution Meta-Kernel Solution Source Code Solution Sample Output Extra Credit Task statements and questions Solutions and answers Obtaining Target States and Positions (getsta) Task Statement Learning Goals Approach Solution Solution Meta-Kernel Solution Source Code Solution Sample Output Extra Credit Task statements and questions Solutions and answers Spacecraft Orientation and Reference Frames (xform) Task Statement Learning Goals Approach Solution Solution Meta-Kernel Solution Source Code Solution Sample Output Extra Credit Task statements and questions Solutions and answers Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts) Task Statement Learning Goals Approach Solution Solution Meta-Kernel Solution Source Code Solution Sample Output Extra Credit Task statements and questions Solutions and answers Intersecting Vectors with an Ellipsoid and a DSK (fovint) Task Statement Learning Goals Approach Solution Solution Meta-Kernel Solution Source Code Solution Sample Output Extra Credit Remote Sensing Hands-On Lesson, using TGO (C)
Overview
Note About HTML Links
In order for the links to be resolved, if not done already by installing the lessons package under the Toolkit's ``doc/html'' directory, create a subdirectory called ``lessons'' under the ``doc/html'' directory of the ``cspice/'' tree and copy this document to that subdirectory before loading it into a Web browser. References
Of these documents, the ``Tutorials'' contains the highest level descriptions with the least number of details while the ``Required Reading'' documents contain much more detailed specifications. The most complete specifications are provided in the ``API Documentation''. In some cases the lesson explanations also refer to the information provided in the meta-data area of the kernels used in the lesson examples. It is especially true in case of the FK and IK files, which often contain comprehensive descriptions of the frames, instrument FOVs, etc. Since both the FK and IK are text kernels, the information provided in them can be viewed using any text editor, while the meta information provided in binary kernels---SPKs and CKs---can be viewed using ``commnt'' or ``spacit'' utility programs located in ``cspice/exe'' of Toolkit installation tree. Tutorials
Name Lesson steps/functions it describes ---------------- ----------------------------------------------- Time Time Conversion SCLK and LSK Time Conversion SPK Obtaining Ephemeris Data Frames Reference Frames Using Frames Reference Frames PCK Planetary Constants Data CK Spacecraft Orientation Data DSK Detailed Target Shape (Topography) DataThese tutorials are available from the NAIF ftp server at JPL:
http://naif.jpl.nasa.gov/naif/tutorials.html Required Readings
Name Lesson steps/functions that it describes --------------- ----------------------------------------- ck.req Obtaining spacecraft orientation data dsk.req Obtaining detailed body shape data frames.req Using reference frames naif_ids.req Determining body ID codes pck.req Obtaining planetary constants data sclk.req SCLK time conversion spk.req Obtaining ephemeris data time.req Time conversion The Permuted Index
This text document provides a simple mechanism by which users can discover which CSPICE functions perform functions of interest, as well as the names of the source files that contain these functions. API Documentation
For example the path of the source code of the str2et_c routine is
cspice/src/cspice/str2et_c.c Kernels Used
1. Generic LSK:
naif0012.tls
2. ExoMars-16 TGO SCLK:
em16_tgo_step_20160414.tsc
3. Solar System Ephemeris SPK, subsetted to cover only the time
range of interest:
de430.bsp
4. Martian Satellite Ephemeris SPK, subsetted to cover only the time
range of interest:
mar085.bsp
5. ExoMars-16 TGO Spacecraft Trajectory SPK, subsetted to cover only
the time range of interest:
em16_tgo_mlt_20171205_20230115_v01.bsp
6. Generic PCK:
pck00010.tpc
7. ExoMars-16 TGO FK:
em16_tgo_v07.tf
8. ExoMars-16 TGO Spacecraft CK, subsetted to cover only the time
range of interest:
em16_tgo_sc_slt_npo_20171205_20230115_s20160414_v01.bc
9. Low-resolution Mars DSK:
mars_lowres.bds
10. NOMAD IK:
em16_tgo_nomad_v02.ti
These SPICE kernels are included in the lesson package available from
the NAIF server at JPL:
ftp://naif.jpl.nasa.gov/pub/naif/toolkit_docs/Lessons/In addition to these kernels, the extra credit exercises require the following kernels:
11. Generic Jovian Satellite Ephemeris SPK:
jup310_2018.bsp
12. EDM lander FK:
em16_edm_v00.tf
13. EDM landing site SPK:
em16_edm_sot_landing_site_20161020_21000101_v01.bsp
These SPICE kernels are available from the NAIF server at JPL:
https://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/ https://naif.jpl.nasa.gov/pub/naif/EXOMARS2016/kernels/ CSPICE Modules Used
CHAPTER EXERCISE FUNCTIONS NON-VOID KERNELS
------- --------- --------- --------- ----------
1 convtm furnsh_c 1,2
prompt_c
str2et_c
etcal_c
timout_c
sce2s_c
extra (*) unload_c unitim_c 1,2
sct2e_c
et2utc_c
scs2e_c
2 getsta furnsh_c vnorm_c 1,3-5
prompt_c
str2et_c
spkezr_c
spkpos_c
convrt_c
extra (*) kclear_c 1,3-6,11-13
unload_c
bodn2c_c
3 xform furnsh_c vsep_c 1-8
prompt_c
str2et_c
spkezr_c
sxform_c
mxvg_c
spkpos_c
pxform_c
mxv_c
convrt_c
extra (*) kclear_c 1-8
unload_c
4 subpts furnsh_c vnorm_c 1,3-6,9
prompt_c
str2et_c
subpnt_c
subslr_c
extra (*) kclear_c dpr_c 1,3-6
reclat_c
bodvrd_c
recpgr_c
5 fovint furnsh_c dpr_c 1-10
prompt_c
str2et_c
bodn2c_c
getfov_c
sincpt_c
reclat_c
illumf_c
et2lst_c
(*) Additional APIs and kernels used in Extra Credit tasks.
Refer to the headers of the various functions listed above, as detailed
interface specifications are provided with the source code.
Time Conversion (convtm)Task Statement
Learning Goals
Approach
When completing the ``calendar format'' step above, consider using one of two possible methods: etcal_c or timout_c. SolutionSolution Meta-Kernel
KPL/MK
This is the meta-kernel used in the solution of the ``Time
Conversion'' task in the Remote Sensing Hands On Lesson.
The names and contents of the kernels referenced by this
meta-kernel are as follows:
1. Generic LSK:
naif0012.tls
2. ExoMars-16 TGO SCLK:
em16_tgo_step_20160414.tsc
\begindata
KERNELS_TO_LOAD = (
'kernels/lsk/naif0012.tls',
'kernels/sclk/em16_tgo_step_20160414.tsc'
)
\begintext
Solution Source Code
#include <stdio.h>
/*
Standard CSPICE User Include File
*/
#include "SpiceUsr.h"
/*
Local Parameters
*/
#define METAKR "convtm.tm"
#define SCLKID -143
#define STRLEN 50
int main (void)
{
/*
Local Variables
*/
SpiceChar calet [STRLEN];
SpiceChar sclkst [STRLEN];
SpiceChar utctim [STRLEN];
SpiceDouble et;
/*
Load the kernels this program requires.
Both the spacecraft clock kernel and a
leapseconds kernel should be listed in
the meta-kernel.
*/
furnsh_c ( METAKR );
/*
Prompt the user for the input time string.
*/
prompt_c ( "Input UTC Time: ", STRLEN, utctim );
printf ( "Converting UTC Time: %s\n", utctim );
/*
Convert utctim to ET.
*/
str2et_c ( utctim, &et );
printf ( " ET Seconds Past J2000: %16.3f\n", et );
/*
Now convert ET to a calendar time
string. This can be accomplished in two
ways.
*/
etcal_c ( et, STRLEN, calet );
printf ( " Calendar ET (etcal_c): %s\n", calet );
/*
Or use timout_c for finer control over the
output format. The picture below was built
by examining the header of timout_c.
*/
timout_c ( et, "YYYY-MON-DDTHR:MN:SC ::TDB",
STRLEN, calet );
printf ( " Calendar ET (timout_c): %s\n", calet );
/*
Convert ET to spacecraft clock time.
*/
sce2s_c ( SCLKID, et, STRLEN, sclkst );
printf ( " Spacecraft Clock Time: %s\n", sclkst );
return(0);
}
Solution Sample Output
Input UTC Time: 2018 JUN 11 19:32:00
Converting UTC Time: 2018 JUN 11 19:32:00
ET Seconds Past J2000: 582017589.185
Calendar ET (etcal_c): 2018 JUN 11 19:33:09.184
Calendar ET (timout_c): 2018-JUN-11T19:33:09
Spacecraft Clock Time: 1/0070841719.26698
Extra Credit
These ``extra credit'' tasks are provided as task statements, and unlike the regular tasks, no approach or solution source code is provided. In the next section, you will find the numeric solutions (when applicable) and answers to the questions asked in these tasks. Task statements and questions
Solutions and answers
Julian Date TDB: 2458281.3146896
===================================================================== =========== Toolkit version: N0066 SPICE(NOLEAPSECONDS) -- The variable that points to the leapseconds (DELTET/DELTA_AT) could n ot be located in the kernel pool. It is likely that the leapseconds kernel has not been loaded via the routine FURNSH. A traceback follows. The name of the highest level module is first. str2et_c --> STR2ET --> TTRANS Oh, by the way: The SPICELIB error handling actions are USER-TAILORA BLE. You can choose whether the Toolkit aborts or continues when errors occur, which error messages to output, and where to send the output. Please read the ERROR "Required Reading" file, or see the routines ERRACT, ERRDEV, and ERRP RT. ===================================================================== ===========
===================================================================== =========== Toolkit version: N0066 SPICE(KERNELVARNOTFOUND) -- The Variable Was not Found in the Kernel Pool. SCLK_DATA_TYPE_143 not found. Did you load the SCLK kernel? A traceback follows. The name of the highest level module is first. sce2s_c --> SCE2S --> SCE2T --> SCTYPE --> SCLI01 Oh, by the way: The SPICELIB error handling actions are USER-TAILORA BLE. You can choose whether the Toolkit aborts or continues when errors occur, which error messages to output, and where to send the output. Please read the ERROR "Required Reading" file, or see the routines ERRACT, ERRDEV, and ERRP RT. ===================================================================== ===========
Earliest UTC convertible to SCLK: 2016-03-13T21:34:13.194
Spacecraft Clock Time: 1/0070841719.26698
UTC time from spacecraft clock: 2018-06-11T19:32:00.000
Obtaining Target States and Positions (getsta)Task Statement
Learning Goals
Approach
When deciding which SPK files to load, the Toolkit utility ``brief'' may be of some use. ``brief'' is located in the ``cspice/exe'' directory for C toolkits. Consult its user's guide available in ``cspice/doc/brief.ug'' for details. SolutionSolution Meta-Kernel
KPL/MK
This is the meta-kernel used in the solution of the
``Obtaining Target States and Positions'' task in the
Remote Sensing Hands On Lesson.
The names and contents of the kernels referenced by this
meta-kernel are as follows:
1. Generic LSK:
naif0012.tls
2. Solar System Ephemeris SPK, subsetted to cover only
the time range of interest:
de430.bsp
3. Martian Satellite Ephemeris SPK, subsetted to cover
only the time range of interest:
mar085.bsp
4. ExoMars-16 TGO Spacecraft Trajectory SPK, subsetted
to cover only the time range of interest:
em16_tgo_mlt_20171205_20230115_v01.bsp
\begindata
KERNELS_TO_LOAD = (
'kernels/lsk/naif0012.tls',
'kernels/spk/de430.bsp',
'kernels/spk/mar085.bsp',
'kernels/spk/em16_tgo_mlt_20171205_20230115_v01.bsp',
)
\begintext
Solution Source Code
#include <stdio.h>
/*
Standard CSPICE User Include File
*/
#include "SpiceUsr.h"
/*
Local Parameters
*/
#define METAKR "getsta.tm"
#define STRLEN 50
int main (void)
{
/*
Local Variables
*/
SpiceChar utctim [STRLEN];
SpiceDouble dist;
SpiceDouble et;
SpiceDouble ltime;
SpiceDouble pos [3];
SpiceDouble state [6];
/*
Load the kernels that this program requires. We
will need a leapseconds kernel to convert input
UTC time strings into ET. We also will need the
necessary SPK files with coverage for the bodies
in which we are interested.
*/
furnsh_c ( METAKR );
/*
Prompt the user for the input time string.
*/
prompt_c ( "Input UTC Time: ", STRLEN, utctim );
printf ( "Converting UTC Time: %s\n", utctim );
/*
Convert utctim to ET.
*/
str2et_c ( utctim, &et );
printf ( " ET seconds past J2000: %16.3f\n", et );
/*
Compute the apparent state of Mars as seen from
ExoMars-16 TGO in the J2000 frame. All of the ephemeris
readers return states in units of kilometers and
kilometers per second.
*/
spkezr_c ( "MARS", et, "J2000", "LT+S",
"TGO", state, <ime );
printf ( " Apparent state of Mars as seen "
"from ExoMars-16 TGO in the J2000\n" );
printf ( " frame (km, km/s):\n" );
printf ( " X = %16.3f\n", state[0] );
printf ( " Y = %16.3f\n", state[1] );
printf ( " Z = %16.3f\n", state[2] );
printf ( " VX = %16.3f\n", state[3] );
printf ( " VY = %16.3f\n", state[4] );
printf ( " VZ = %16.3f\n", state[5] );
/*
Compute the apparent position of Earth as seen from
ExoMars-16 TGO in the J2000 frame. Note: We could have
continued using spkezr_c and simply ignored the velocity
components.
*/
spkpos_c ( "EARTH", et, "J2000", "LT+S",
"TGO", pos, <ime );
printf ( " Apparent position of Earth as seen "
"from ExoMars-16 TGO in the\n" );
printf ( " J2000 frame (km): \n" );
printf ( " X = %16.3f\n", pos[0] );
printf ( " Y = %16.3f\n", pos[1] );
printf ( " Z = %16.3f\n", pos[2] );
/*
We need only display LTIME, as it is precisely the
light time in which we are interested.
*/
printf ( " One way light time between ExoMars-16 "
"TGO and the apparent\n" );
printf ( " position of Earth (seconds): "
"%16.3f\n", ltime );
/*
Compute the apparent position of the Sun as seen
from Mars in the J2000 frame.
*/
spkpos_c ( "SUN", et, "J2000", "LT+S",
"MARS", pos, <ime );
printf ( " Apparent position of Sun as seen "
"from Mars in the\n" );
printf ( " J2000 frame (km): \n" );
printf ( " X = %16.3f\n", pos[0] );
printf ( " Y = %16.3f\n", pos[1] );
printf ( " Z = %16.3f\n", pos[2] );
/*
Now we need to compute the actual distance between
the Sun and Mars. The above SPKPOS call gives us
the apparent distance, so we need to adjust our
aberration correction appropriately.
*/
spkpos_c ( "SUN", et, "J2000", "NONE",
"MARS", pos, <ime );
/*
Compute the distance between the body centers in
kilometers.
*/
dist = vnorm_c ( pos );
/*
Convert this value to AU using convrt_c.
*/
convrt_c ( dist, "KM", "AU", &dist );
printf ( " Actual distance between Sun and "
"Mars body centers:\n" );
printf ( " (AU): %16.3f\n", dist );
return(0);
}
Solution Sample Output
Input UTC Time: 2018 JUN 11 19:32:00
Converting UTC Time: 2018 JUN 11 19:32:00
ET seconds past J2000: 582017589.185
Apparent state of Mars as seen from ExoMars-16 TGO in the J2000
frame (km, km/s):
X = 2911.822
Y = -2033.802
Z = -1291.701
VX = 1.310
VY = -0.056
VZ = 3.104
Apparent position of Earth as seen from ExoMars-16 TGO in the
J2000 frame (km):
X = -49609884.080
Y = 57070665.862
Z = 30304236.930
One way light time between ExoMars-16 TGO and the apparent
position of Earth (seconds): 271.738
Apparent position of Sun as seen from Mars in the
J2000 frame (km):
X = -24712734.289
Y = 194560532.943
Z = 89906636.789
Actual distance between Sun and Mars body centers:
(AU): 1.442
Extra Credit
These ``extra credit'' tasks are provided as task statements, and unlike the regular tasks, no approach or solution source code is provided. In the next section, you will find the numeric solutions (when applicable) and answers to the questions asked in these tasks. Task statements and questions
Solutions and answers
===================================================================== =========== Toolkit version: N0066 SPICE(SPKINSUFFDATA) -- Insufficient ephemeris data has been loaded to compute the state of - 143 (EXOMARS 2016 TGO) relative to 0 (SOLAR SYSTEM BARYCENTER) at the eph emeris epoch 2018 JUN 11 19:33:09.184. A traceback follows. The name of the highest level module is first. spkezr_c --> SPKEZR --> SPKEZ --> SPKACS --> SPKGEO Oh, by the way: The SPICELIB error handling actions are USER-TAILORA BLE. You can choose whether the Toolkit aborts or continues when errors occur, which error messages to output, and where to send the output. Please read the ERROR "Required Reading" file, or see the routines ERRACT, ERRDEV, and ERRP RT. ===================================================================== ===========
BRIEF -- Version 4.0.0, September 8, 2010 -- Toolkit Version N0066
Summary for: kernels/spk/de430.bsp
Bodies: MERCURY BARYCENTER (1) w.r.t. SOLAR SYSTEM BARYCENTER (0)
VENUS BARYCENTER (2) w.r.t. SOLAR SYSTEM BARYCENTER (0)
EARTH BARYCENTER (3) w.r.t. SOLAR SYSTEM BARYCENTER (0)
MARS BARYCENTER (4) w.r.t. SOLAR SYSTEM BARYCENTER (0)
JUPITER BARYCENTER (5) w.r.t. SOLAR SYSTEM BARYCENTER (0)
SATURN BARYCENTER (6) w.r.t. SOLAR SYSTEM BARYCENTER (0)
URANUS BARYCENTER (7) w.r.t. SOLAR SYSTEM BARYCENTER (0)
NEPTUNE BARYCENTER (8) w.r.t. SOLAR SYSTEM BARYCENTER (0)
PLUTO BARYCENTER (9) w.r.t. SOLAR SYSTEM BARYCENTER (0)
SUN (10) w.r.t. SOLAR SYSTEM BARYCENTER (0)
MERCURY (199) w.r.t. MERCURY BARYCENTER (1)
VENUS (299) w.r.t. VENUS BARYCENTER (2)
MOON (301) w.r.t. EARTH BARYCENTER (3)
EARTH (399) w.r.t. EARTH BARYCENTER (3)
Start of Interval (UTC) End of Interval (UTC)
----------------------------- -------------------------
----
2018-JUN-09 23:30:00.000 2018-JUN-14 12:00:00.000
Summary for: kernels/spk/mar085.bsp
Bodies: EARTH BARYCENTER (3) w.r.t. SOLAR SYSTEM BARYCENTER (0)
MARS BARYCENTER (4) w.r.t. SOLAR SYSTEM BARYCENTER (0)
SUN (10) w.r.t. SOLAR SYSTEM BARYCENTER (0)
EARTH (399) w.r.t. EARTH BARYCENTER (3)
PHOBOS (401) w.r.t. MARS BARYCENTER (4)
DEIMOS (402) w.r.t. MARS BARYCENTER (4)
MARS (499) w.r.t. MARS BARYCENTER (4)
Start of Interval (UTC) End of Interval (UTC)
----------------------------- -------------------------
----
2018-JUN-09 23:30:00.000 2018-JUN-14 12:00:00.000
Summary for: kernels/spk/em16_tgo_mlt_20171205_20230115_v01.bsp
Body: EXOMARS 2016 TGO (-143) w.r.t. MARS (499)
Start of Interval (UTC) End of Interval (UTC)
----------------------------- ---------------------------
--
2018-JUN-09 23:30:00.000 2018-JUN-14 12:00:00.000
Additional kernels required for this task:
1. Generic Jovian Satellite Ephemeris SPK:
jup310_2018.bsp
available in the NAIF server at:
https://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/
satellites/a_old_versions
Actual position of Jupiter as seen from Mars in the
J2000 frame (km):
X = -536521483.294
Y = -384722940.461
Z = -145930841.439
Additional kernels required for this task:
1. EDM lander FK:
em16_edm_v00.tf
2. EDM landing site SPK:
em16_edm_sot_landing_site_20161020_21000101_v01.bsp
3. Generic PCK:
pck00010.tpc
available in the NAIF server at:
https://naif.jpl.nasa.gov/pub/naif/EXOMARS2016/kernels/
EDM_LANDING_SITE NAIF ID: -117900
Apparent position of EDM Landing Site as seen from
ExoMars-16 TGO in the J2000 frame (km):
X = -131.716
Y = -2168.989
Z = 208.792
Actual (geometric) position of Sun as seen from Mars in the
J2000 frame (km):
X = -24730874.909
Y = 194558449.463
Z = 89906170.829
Light-time corrected position of Sun as seen from Mars in the
J2000 frame (km):
X = -24730866.197
Y = 194558445.149
Z = 89906168.728
Apparent position of Sun as seen from Mars in the
J2000 frame (km):
X = -24712733.997
Y = 194560532.846
Z = 89906636.764
Spacecraft Orientation and Reference Frames (xform)Task Statement
Learning Goals
Approach
You may find it useful to consult the permuted index, the headers of various source modules, and the following toolkit documentation:
SolutionSolution Meta-Kernel
KPL/MK
This is the meta-kernel used in the solution of the ``Spacecraft
Orientation and Reference Frames'' task in the Remote Sensing
Hands On Lesson.
The names and contents of the kernels referenced by this
meta-kernel are as follows:
1. Generic LSK:
naif0012.tls
2. ExoMars-16 TGO SCLK:
em16_tgo_step_20160414.tsc
3. Solar System Ephemeris SPK, subsetted to cover only
the time range of interest:
de430.bsp
4. Martian Satellite Ephemeris SPK, subsetted to cover
only the time range of interest:
mar085.bsp
5. ExoMars-16 TGO Spacecraft Trajectory SPK, subsetted
to cover only the time range of interest:
em16_tgo_mlt_20171205_20230115_v01.bsp
6. ExoMars-16 TGO FK:
em16_tgo_v07.tf
7. ExoMars-16 TGO Spacecraft CK, subsetted to cover only
the time range of interest:
em16_tgo_sc_slt_npo_20171205_20230115_s20160414_v01.bc
8. Generic PCK:
pck00010.tpc
\begindata
KERNELS_TO_LOAD = (
'kernels/lsk/naif0012.tls',
'kernels/sclk/em16_tgo_step_20160414.tsc',
'kernels/spk/de430.bsp',
'kernels/spk/mar085.bsp',
'kernels/spk/em16_tgo_mlt_20171205_20230115_v01.bsp',
'kernels/fk/em16_tgo_v07.tf',
'kernels/ck/em16_tgo_sc_slt_npo_20171205_20230115_s20160414_v01.bc',
'kernels/pck/pck00010.tpc'
)
\begintext
Solution Source Code
#include <stdio.h>
/*
Standard CSPICE User Include File
*/
#include "SpiceUsr.h"
/*
Local Parameters
*/
#define METAKR "xform.tm"
#define STRLEN 50
int main (void)
{
/*
Local Variables
*/
SpiceChar utctim [STRLEN];
SpiceDouble et;
SpiceDouble ltime;
SpiceDouble state [6];
SpiceDouble bfixst [6];
SpiceDouble pos [3];
SpiceDouble sform [6][6];
SpiceDouble pform [3][3];
SpiceDouble bsight [3];
SpiceDouble sep;
/*
Load the kernels that this program requires. We
will need:
A leapseconds kernel
A spacecraft clock kernel for ExoMars-16 TGO
The necessary ephemerides
A planetary constants file (PCK)
A spacecraft orientation kernel for ExoMars-16 TGO (CK)
A frame kernel (TF)
*/
furnsh_c ( METAKR );
/*
Prompt the user for the input time string.
*/
prompt_c ( "Input UTC Time: ", STRLEN, utctim );
printf ( "Converting UTC Time: %s\n", utctim );
/*
Convert utctim to ET.
*/
str2et_c ( utctim, &et );
printf ( " ET seconds past J2000: %16.3f\n", et );
/*
Compute the apparent state of Mars as seen from
ExoMars-16 TGO in the J2000 reference frame.
*/
spkezr_c ( "MARS", et, "J2000", "LT+S",
"TGO", state, <ime );
/*
Now obtain the transformation from the inertial
J2000 frame to the non-inertial body-fixed IAU_MARS
frame. Since we want the apparent position, we
need to subtract ltime from et.
*/
sxform_c ( "J2000", "IAU_MARS", et-ltime, sform );
/*
Now rotate the apparent J2000 state into IAU_MARS
with the following matrix multiplication:
*/
mxvg_c ( sform, state, 6, 6, bfixst );
/*
Display the results.
*/
printf ( " Apparent state of Mars as seen "
"from ExoMars-16 TGO in the IAU_MARS\n" );
printf ( " body-fixed frame (km, km/s):\n" );
printf ( " X = %19.6f\n", bfixst[0] );
printf ( " Y = %19.6f\n", bfixst[1] );
printf ( " Z = %19.6f\n", bfixst[2] );
printf ( " VX = %19.6f\n", bfixst[3] );
printf ( " VY = %19.6f\n", bfixst[4] );
printf ( " VZ = %19.6f\n", bfixst[5] );
/*
It is worth pointing out, all of the above could
have been done with a single use of spkezr_c:
*/
spkezr_c ( "MARS", et, "IAU_MARS", "LT+S",
"TGO", state, <ime );
/*
Display the results.
*/
printf ( " Apparent state of Mars as seen "
"from ExoMars-16 TGO in the IAU_MARS\n" );
printf ( " body-fixed frame (km, km/s) "
"obtained using spkezr_c directly:\n" );
printf ( " X = %19.6f\n", state[0] );
printf ( " Y = %19.6f\n", state[1] );
printf ( " Z = %19.6f\n", state[2] );
printf ( " VX = %19.6f\n", state[3] );
printf ( " VY = %19.6f\n", state[4] );
printf ( " VZ = %19.6f\n", state[5] );
/*
Note that the velocity found by using spkezr_c
to compute the state in the IAU_MARS frame differs
at the few mm/second level from that found previously
by calling spkezr_c and then sxform_c. Computing
velocity via a single call to spkezr_c as we've
done immediately above is slightly more accurate because
it accounts for the effect of the rate of change of
light time on the apparent angular velocity of the
target's body-fixed reference frame.
Now we are to compute the angular separation between
the apparent position of Mars as seen from the orbiter
and the nominal instrument view direction. First,
compute the apparent position of Mars as seen from
ExoMars-16 TGO in the J2000 frame.
*/
spkpos_c ( "MARS", et, "J2000", "LT+S",
"TGO", pos, <ime );
/*
Now compute the location of the nominal instrument view
direction. From reading the frame kernel we know that
the instrument view direction is nominally the -Y axis
of the TGO_SPACECRAFT frame defined there.
*/
bsight[0] = 0.0;
bsight[1] = -1.0;
bsight[2] = 0.0;
/*
Now compute the rotation matrix from TGO_SPACECRAFT
into J2000.
*/
pxform_c ( "TGO_SPACECRAFT", "J2000", et, pform );
/*
And multiply the result to obtain the nominal instrument
view direction in the J2000 reference frame.
*/
mxv_c ( pform, bsight, bsight );
/*
Lastly compute the angular separation.
*/
convrt_c ( vsep_c(bsight, pos), "RADIANS",
"DEGREES", &sep );
printf ( " Angular separation between the "
"apparent position of Mars and the\n" );
printf ( " ExoMars-16 TGO nominal "
"instrument view direction (degrees): \n" );
printf ( " %16.3f\n", sep );
/*
Or alternatively we can work in the spacecraft
frame directly.
*/
spkpos_c ( "MARS", et, "TGO_SPACECRAFT", "LT+S",
"TGO", pos, <ime );
/*
The nominal instrument view direction is the -Y-axis
in the TGO_SPACECRAFT frame.
*/
bsight[0] = 0.0;
bsight[1] = -1.0;
bsight[2] = 0.0;
/*
Lastly compute the angular separation.
*/
convrt_c ( vsep_c(bsight, pos), "RADIANS",
"DEGREES", &sep );
printf ( " Angular separation between the "
"apparent position of Mars and the\n" );
printf ( " ExoMars-16 TGO nominal "
"instrument view direction computed\n" );
printf ( " using vectors in the "
"TGO_SPACECRAFT frame (degrees):\n" );
printf ( " %16.3f\n", sep );
return(0);
}
Solution Sample Output
Input UTC Time: 2018 JUN 11 19:32:00
Converting UTC Time: 2018 JUN 11 19:32:00
ET seconds past J2000: 582017589.185
Apparent state of Mars as seen from ExoMars-16 TGO in the IAU_MARS
body-fixed frame (km, km/s):
X = -2843.464125
Y = 2235.459544
Z = 1095.894969
VX = 0.311443
VY = -1.151929
VZ = 3.082123
Apparent state of Mars as seen from ExoMars-16 TGO in the IAU_MARS
body-fixed frame (km, km/s) obtained using spkezr_c directly:
X = -2843.464125
Y = 2235.459544
Z = 1095.894969
VX = 0.311443
VY = -1.151929
VZ = 3.082123
Angular separation between the apparent position of Mars and the
ExoMars-16 TGO nominal instrument view direction (degrees):
5.438
Angular separation between the apparent position of Mars and the
ExoMars-16 TGO nominal instrument view direction computed
using vectors in the TGO_SPACECRAFT frame (degrees):
5.438
Extra Credit
These ``extra credit'' tasks are provided as task statements, and unlike the regular tasks, no approach or solution source code is provided. In the next section, you will find the numeric solutions (when applicable) and answers to the questions asked in these tasks. Task statements and questions
Solutions and answers
=====================================================================
===========
Toolkit version: N0066
SPICE(NOFRAMECONNECT) --
At epoch 5.8209996918462E+08 TDB (2018 JUN 12 18:26:09.184 TDB), ther
e is
insufficient information available to transform from reference frame
-143000
(TGO_SPACECRAFT) to reference frame 1 (J2000). TGO_SPACECRAFT is a CK
frame; a
CK file containing data for instrument or structure -143000 at the ep
och shown
above, as well as a corresponding SCLK kernel, must be loaded in orde
r to use
this frame. Failure to find required CK data could be due to one or m
ore CK
files not having been loaded, or to the epoch shown above lying withi
n a
coverage gap or beyond the coverage bounds of the loaded CK files. It
is also
possible that no loaded CK file has required angular velocity data fo
r the
input epoch, even if a loaded CK does have attitude data for that epo
ch. You
can use CKBRIEF with the -dump option to display coverage intervals o
f a CK
file.
A traceback follows. The name of the highest level module is first.
pxform_c --> PXFORM --> REFCHG
Oh, by the way: The SPICELIB error handling actions are USER-TAILORA
BLE. You
can choose whether the Toolkit aborts or continues when errors occur,
which
error messages to output, and where to send the output. Please read
the ERROR
"Required Reading" file, or see the routines ERRACT, ERRDEV, and ERRP
RT.
=====================================================================
===========
CKBRIEF -- Version 6.1.0, June 27, 2014 -- Toolkit Version N0066
Summary for: kernels/ck/em16_tgo_sc_slt_npo_20171205_20230115_s201604
14_v01.bc
Segment No.: 1
Object: -143000
Interval Begin UTC Interval End UTC AV
------------------------ ------------------------ ---
2018-JUN-10 23:59:59.999 2018-JUN-12 06:26:53.918 Y
2018-JUN-12 06:56:53.918 2018-JUN-12 18:14:33.918 Y
2018-JUN-12 18:44:33.918 2018-JUN-13 04:02:13.918 Y
2018-JUN-13 04:32:13.918 2018-JUN-13 07:58:33.918 Y
2018-JUN-13 08:28:33.918 2018-JUN-13 11:59:59.999 Y
CKBRIEF -- Version 6.1.0, June 27, 2014 -- Toolkit Version N0066
Summary for: kernels/ck/em16_tgo_sc_slt_npo_20171205_20230115_s201604
14_v01.bc
Object: -143000
Interval Begin UTC Interval End UTC AV
------------------------ ------------------------ ---
2018-JUN-10 23:59:59.999 2018-JUN-13 11:59:59.999 Y
Angular separation between the apparent position of the Sun and the
ExoMars-16 TGO nominal instrument view direction (degrees):
130.543
Science Deck illumination:
ExoMars-16 TGO Science Deck IS NOT illuminated.
Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)Task Statement
near point/ellipsoid
definition, and once using a DSK shape model and the
nadir/dsk/unprioritized
definition.
The program displays the results. Use the program to compute these quantities at "2018 JUN 11 19:32:00" UTC. Learning Goals
Approach
One point worth considering: how would the results change if the sub-solar and sub-observer points were computed using the
intercept/ellipsoid
and
intercept/dsk/unprioritized
definitions? Which definition is appropriate?
SolutionSolution Meta-Kernel
KPL/MK
This is the meta-kernel used in the solution of the
``Computing Sub-s/c and Sub-solar Points on an Ellipsoid
and a DSK'' task in the Remote Sensing Hands On Lesson.
The names and contents of the kernels referenced by this
meta-kernel are as follows:
1. Generic LSK:
naif0012.tls
2. Solar System Ephemeris SPK, subsetted to cover only
the time range of interest:
de430.bsp
3. Martian Satellite Ephemeris SPK, subsetted to cover
only the time range of interest:
mar085.bsp
4. ExoMars-16 TGO Spacecraft Trajectory SPK, subsetted
to cover only the time range of interest:
em16_tgo_mlt_20171205_20230115_v01.bsp
5. Generic PCK:
pck00010.tpc
6. Low-resolution Mars DSK:
mars_lowres.bds
\begindata
KERNELS_TO_LOAD = (
'kernels/lsk/naif0012.tls',
'kernels/spk/de430.bsp',
'kernels/spk/mar085.bsp',
'kernels/spk/em16_tgo_mlt_20171205_20230115_v01.bsp',
'kernels/pck/pck00010.tpc'
'kernels/dsk/mars_lowres.bds'
)
\begintext
Solution Source Code
#include <stdio.h>
/*
Standard CSPICE User Include File
*/
#include "SpiceUsr.h"
/*
Local Parameters
*/
#define METAKR "subpts.tm"
#define STRLEN 50
int main (void)
{
/*
Local Variables
*/
SpiceChar * method;
SpiceChar utctim [STRLEN];
SpiceDouble et;
SpiceDouble spoint [3];
SpiceDouble srfvec [3];
SpiceDouble trgepc;
SpiceInt i;
/*
Load the kernels that this program requires. We
will need:
A leapseconds kernel
The necessary ephemerides
A planetary constants file (PCK)
A DSK file containing Mars shape data
*/
furnsh_c ( METAKR );
/*
Prompt the user for the input time string.
*/
prompt_c ( "Input UTC Time: ", STRLEN, utctim );
printf ( " Converting UTC Time: %s\n", utctim );
/*
Convert utctim to ET.
*/
str2et_c ( utctim, &et );
printf ( " ET seconds past J2000: %16.3f\n", et );
for ( i = 0; i < 2; i++ )
{
if ( i == 0 )
{
/*
Use the "near point" sub-point definition
and an ellipsoidal model.
*/
method = "NEAR POINT/Ellipsoid";
}
else
{
/*
Use the "nadir" sub-point definition
and a DSK model.
*/
method = "NADIR/DSK/Unprioritized";
}
printf ( "\n Sub-point/target shape model: %s\n\n",
method );
/*
Compute the apparent sub-observer point of ExoMars-16 TGO
on Mars.
*/
subpnt_c ( method,
"MARS", et, "IAU_MARS", "LT+S",
"TGO", spoint, &trgepc, srfvec );
printf ( " Apparent sub-observer point of ExoMars-16 "
"TGO on Mars\n" );
printf ( " in the IAU_MARS frame (km):\n" );
printf ( " X = %16.3f\n", spoint[0] );
printf ( " Y = %16.3f\n", spoint[1] );
printf ( " Z = %16.3f\n", spoint[2] );
printf ( " ALT = %16.3f\n", vnorm_c(srfvec) );
/*
Compute the apparent sub-solar point on Mars
as seen from ExoMars-16 TGO.
*/
subslr_c ( method,
"MARS", et, "IAU_MARS", "LT+S",
"TGO", spoint, &trgepc, srfvec );
printf ( " Apparent sub-solar point on Mars "
"as seen from ExoMars-16\n" );
printf ( " TGO in the IAU_MARS frame (km):\n" );
printf ( " X = %16.3f\n", spoint[0] );
printf ( " Y = %16.3f\n", spoint[1] );
printf ( " Z = %16.3f\n", spoint[2] );
}
printf ( "\n" );
return(0);
}
Solution Sample Output
Input UTC Time: 2018 JUN 11 19:32:00
Converting UTC Time: 2018 JUN 11 19:32:00
ET seconds past J2000: 582017589.185
Sub-point/target shape model: NEAR POINT/Ellipsoid
Apparent sub-observer point of ExoMars-16 TGO on Mars
in the IAU_MARS frame (km):
X = 2554.165
Y = -2008.010
Z = -983.240
ALT = 385.045
Apparent sub-solar point on Mars as seen from ExoMars-16
TGO in the IAU_MARS frame (km):
X = 487.589
Y = -3348.610
Z = -286.697
Sub-point/target shape model: NADIR/DSK/Unprioritized
Apparent sub-observer point of ExoMars-16 TGO on Mars
in the IAU_MARS frame (km):
X = 2554.223
Y = -2008.057
Z = -983.263
ALT = 384.967
Apparent sub-solar point on Mars as seen from ExoMars-16
TGO in the IAU_MARS frame (km):
X = 488.096
Y = -3352.093
Z = -286.999
Extra Credit
These ``extra credit'' tasks are provided as task statements, and unlike the regular tasks, no approach or solution source code is provided. In the next section, you will find the numeric solutions (when applicable) and answers to the questions asked in these tasks. Task statements and questions
Solutions and answers
Apparent sub-solar point on Mars as seen from ExoMars-16 TGO in
the IAU_MARS frame using the 'Near Point: ellipsoid' method
(km):
X = 487.589
Y = -3348.610
Z = -286.697
Apparent sub-solar point on Mars as seen from ExoMars-16 TGO in
the IAU_MARS frame using the 'Intercept: ellipsoid' method
(km):
X = 487.547
Y = -3348.322
Z = -290.077
Geometric sub-spacecraft point of ExoMars-16 TGO on Phobos in
the IAU_PHOBOS frame using the 'Near Point: ellipsoid' method
(km):
X = 12.059
Y = 4.173
Z = -0.676
Planetocentric coordinates of the ExoMars-16 TGO
sub-spacecraft point on Phobos (degrees, km):
LAT = -3.030
LON = 19.088
R = 12.779
Planetographic coordinates of the ExoMars-16 TGO
sub-spacecraft point on Phobos (degrees, km):
LAT = -6.268
LON = 340.912
ALT = -0.202
Intersecting Vectors with an Ellipsoid and a DSK (fovint)Task Statement
At each point of intersection compute the following:
Additionally compute the local solar time at the intercept of the spectrometer aperture boresight with the surface of Mars, using both ellipsoidal and DSK shape models. Use this program to compute values at the UTC epoch:
Learning Goals
Approach
SolutionSolution Meta-Kernel
KPL/MK
This is the meta-kernel used in the solution of the
``Intersecting Vectors with an Ellipsoid and a DSK'' task
in the Remote Sensing Hands On Lesson.
The names and contents of the kernels referenced by this
meta-kernel are as follows:
1. Generic LSK:
naif0012.tls
2. ExoMars-16 TGO SCLK:
em16_tgo_step_20160414.tsc
3. Solar System Ephemeris SPK, subsetted to cover only
the time range of interest:
de430.bsp
4. Martian Satellite Ephemeris SPK, subsetted to cover
only the time range of interest:
mar085.bsp
5. ExoMars-16 TGO Spacecraft Trajectory SPK, subsetted
to cover only the time range of interest:
em16_tgo_mlt_20171205_20230115_v01.bsp
6. ExoMars-16 TGO FK:
em16_tgo_v07.tf
7. ExoMars-16 TGO Spacecraft CK, subsetted to cover only
the time range of interest:
em16_tgo_sc_slt_npo_20171205_20230115_s20160414_v01.bc
8. Generic PCK:
pck00010.tpc
9. NOMAD IK:
em16_tgo_nomad_v02.ti
10. Low-resolution Mars DSK:
mars_lowres.bds
\begindata
KERNELS_TO_LOAD = (
'kernels/lsk/naif0012.tls',
'kernels/sclk/em16_tgo_step_20160414.tsc',
'kernels/spk/de430.bsp',
'kernels/spk/mar085.bsp',
'kernels/spk/em16_tgo_mlt_20171205_20230115_v01.bsp',
'kernels/fk/em16_tgo_v07.tf',
'kernels/ck/em16_tgo_sc_slt_npo_20171205_20230115_s20160414_v01.bc',
'kernels/pck/pck00010.tpc',
'kernels/ik/em16_tgo_nomad_v02.ti'
'kernels/dsk/mars_lowres.bds'
)
\begintext
Solution Source Code
#include <stdio.h>
/*
Standard CSPICE User Include File
*/
#include "SpiceUsr.h"
#include <stdlib.h>
/*
Local Parameters
*/
#define METAKR "fovint.tm"
#define STRLEN 50
/*
BCVLEN is the maximum number of boundary corner
vectors we can retrieve. We've extended this array by 1
element to make room for the boresight vector.
*/
#define BCVLEN 5
int main (void)
{
/*
Local Variables
*/
SpiceBoolean lit;
SpiceBoolean visibl;
SpiceChar ampm [STRLEN];
SpiceChar *boolst [2] = { "false", "true" };
SpiceChar insfrm [STRLEN];
SpiceChar *method [2];
SpiceChar shape [STRLEN];
SpiceChar time [STRLEN];
SpiceChar utctim [STRLEN];
SpiceChar *vecnam[] = {
"Boundary Corner 1",
"Boundary Corner 2",
"Boundary Corner 3",
"Boundary Corner 4",
"TGO NOMAD LNO Nadir Boresight" };
SpiceDouble bounds [BCVLEN][3];
SpiceDouble bsight [3];
SpiceDouble emissn;
SpiceDouble et;
SpiceDouble lat;
SpiceDouble lon;
SpiceDouble phase;
SpiceDouble point [3];
SpiceDouble radius;
SpiceDouble solar;
SpiceDouble srfvec [3];
SpiceDouble trgepc;
SpiceInt hr;
SpiceInt i;
SpiceInt j;
SpiceInt mn;
SpiceInt n;
SpiceInt lnonid;
SpiceInt marsid;
SpiceInt sc;
SpiceBoolean found;
/*
Load the kernels that this program requires. We
will need:
A leapseconds kernel.
A SCLK kernel for ExoMars-16 TGO.
Any necessary ephemerides.
The ExoMars-16 TGO frame kernel.
An ExoMars-16 TGO C-kernel.
A PCK file with Mars constants.
The ExoMars-16 TGO NOMAD I-kernel.
A DSK file containing Mars shape data.
*/
furnsh_c ( METAKR );
/*
Prompt the user for the input time string.
*/
prompt_c ( "Input UTC Time: ", STRLEN, utctim );
printf ( "Converting UTC Time: %s\n", utctim );
/*
Convert utctim to ET.
*/
str2et_c ( utctim, &et );
printf ( " ET seconds past J2000: %16.3f\n\n", et );
/*
Now we need to obtain the FOV configuration of
the NOMAD LNO Nadir aperture. To do this we will
need the ID code for TGO_NOMAD_LNO_NAD.
*/
bodn2c_c ( "TGO_NOMAD_LNO_NAD", &lnonid, &found );
/*
Stop the program if the code was not found.
*/
if ( !found )
{
printf ( "Unable to locate the ID code for "
"TGO_NOMAD_LNO_NAD\n" );
exit ( EXIT_FAILURE );
}
/*
Now retrieve the field of view parameters.
*/
getfov_c ( lnonid, BCVLEN, STRLEN, STRLEN,
shape, insfrm, bsight, &n, bounds );
/*
Rather than treat BSIGHT as a separate vector,
copy it into the last slot of BOUNDS.
*/
for ( i=0; i<3; i++ )
{
bounds[4][i] = bsight[i];
}
/*
Set values of "method" string that specify use of
ellipsoidal and DSK (topographic) shape models.
In this case, we can use the same methods for calls to both
sincpt_c and ilumin_c. Note that some SPICE routines require
different "method" inputs from those shown here. See the
API documentation of each routine for details.
*/
method[0] = "Ellipsoid";
method[1] = "DSK/Unprioritized";
/*
Get Mars ID. We'll use this ID code later, when we
compute local solar time.
*/
bodn2c_c ( "MARS", &marsid, &found );
/*
The ID code for MARS is built-in to the library.
However, it is good programming practice to get
in the habit of checking your found-flags.
*/
if ( !found )
{
printf ( "Unable to locate the body ID code "
"for Mars.\n" );
exit ( EXIT_FAILURE );
}
/*
Now perform the same set of calculations for each
vector listed in the BOUNDS array. Use both
ellipsoidal and detailed (DSK) shape models.
*/
for ( i=0; i<5; i++ )
{
printf ( "Vector: %s\n", vecnam[i] );
for ( j = 0; j < 2; j++ )
{
printf ( "\n Target shape model: %s\n\n", method[j] );
/*
Call sincpt_c to determine coordinates of the
intersection of this vector with the surface
of Mars.
*/
sincpt_c ( method[j], "MARS", et, "IAU_MARS",
"LT+S", "TGO", insfrm, bounds[i],
point, &trgepc, srfvec, &found );
/*
Check the found flag. Display a message if
the point of intersection was not found,
otherwise continue with the calculations.
*/
if ( !found )
{
printf ( "No intersection point found at "
"this epoch for this vector.\n" );
}
else
{
/*
Now, we have discovered a point of intersection.
Start by displaying the position vector in the
IAU_MARS frame of the intersection.
*/
printf ( " Position vector of surface intercept "
"in the IAU_MARS frame (km):\n" );
printf ( " X = %16.3f\n", point[0] );
printf ( " Y = %16.3f\n", point[1] );
printf ( " Z = %16.3f\n", point[2] );
/*
Display the planetocentric latitude and longitude
of the intercept.
*/
reclat_c ( point, &radius, &lon, &lat );
printf ( " Planetocentric coordinates of "
"the intercept (degrees):\n" );
printf ( " LAT = %16.3f\n", lat * dpr_c() );
printf ( " LON = %16.3f\n", lon * dpr_c() );
/*
Compute the illumination angles at this
point.
*/
illumf_c( method[j], "MARS", "SUN", et,
"IAU_MARS", "LT+S", "TGO", point,
&trgepc, srfvec, &phase, &solar,
&emissn, &visibl, &lit );
printf ( " Phase angle (degrees): "
"%16.3f\n", phase * dpr_c() );
printf ( " Solar incidence angle (degrees): "
"%16.3f\n", solar * dpr_c() );
printf ( " Emission angle (degrees): "
"%16.3f\n", emissn * dpr_c() );
printf ( " Observer visible: %s\n", boolst[visibl] );
printf ( " Sun visible: %s\n", boolst[lit] );
if ( i == 4 )
{
/*
Compute local solar time corresponding to the TDB
light time corrected epoch at the boresignt
intercept.
*/
et2lst_c ( trgepc,
marsid,
lon,
"PLANETOCENTRIC",
STRLEN,
STRLEN,
&hr,
&mn,
&sc,
time,
ampm );
printf ( "\n Local Solar Time at boresight "
"intercept (24 Hour Clock):\n" );
printf ( " %s\n", time );
}
/*
End of LST computation block.
*/
}
/*
End of shape model loop.
*/
}
/*
End of vector loop.
*/
printf ( "\n" );
}
return(0);
}
Solution Sample Output
Input UTC Time: 2018 JUN 11 19:32:00
Converting UTC Time: 2018 JUN 11 19:32:00
ET seconds past J2000: 582017589.185
Vector: Boundary Corner 1
Target shape model: Ellipsoid
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2535.004
Y = -2028.528
Z = -990.594
Planetocentric coordinates of the intercept (degrees):
LAT = -16.967
LON = -38.667
Phase angle (degrees): 48.207
Solar incidence angle (degrees): 43.872
Emission angle (degrees): 4.798
Observer visible: true
Sun visible: true
Target shape model: DSK/Unprioritized
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2535.278
Y = -2028.712
Z = -990.688
Planetocentric coordinates of the intercept (degrees):
LAT = -16.967
LON = -38.667
Phase angle (degrees): 48.207
Solar incidence angle (degrees): 44.387
Emission angle (degrees): 4.326
Observer visible: true
Sun visible: true
Vector: Boundary Corner 2
Target shape model: Ellipsoid
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2525.056
Y = -2042.075
Z = -988.196
Planetocentric coordinates of the intercept (degrees):
LAT = -16.925
LON = -38.963
Phase angle (degrees): 50.707
Solar incidence angle (degrees): 43.586
Emission angle (degrees): 7.432
Observer visible: true
Sun visible: true
Target shape model: DSK/Unprioritized
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2525.359
Y = -2042.259
Z = -988.299
Planetocentric coordinates of the intercept (degrees):
LAT = -16.925
LON = -38.962
Phase angle (degrees): 50.707
Solar incidence angle (degrees): 42.457
Emission angle (degrees): 8.610
Observer visible: true
Sun visible: true
Vector: Boundary Corner 3
Target shape model: Ellipsoid
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2525.201
Y = -2042.104
Z = -987.770
Planetocentric coordinates of the intercept (degrees):
LAT = -16.917
LON = -38.962
Phase angle (degrees): 50.708
Solar incidence angle (degrees): 43.585
Emission angle (degrees): 7.413
Observer visible: true
Sun visible: true
Target shape model: DSK/Unprioritized
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2525.506
Y = -2042.289
Z = -987.874
Planetocentric coordinates of the intercept (degrees):
LAT = -16.917
LON = -38.961
Phase angle (degrees): 50.708
Solar incidence angle (degrees): 42.457
Emission angle (degrees): 8.593
Observer visible: true
Sun visible: true
Vector: Boundary Corner 4
Target shape model: Ellipsoid
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2535.149
Y = -2028.558
Z = -990.170
Planetocentric coordinates of the intercept (degrees):
LAT = -16.960
LON = -38.666
Phase angle (degrees): 48.208
Solar incidence angle (degrees): 43.871
Emission angle (degrees): 4.769
Observer visible: true
Sun visible: true
Target shape model: DSK/Unprioritized
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2535.423
Y = -2028.741
Z = -990.263
Planetocentric coordinates of the intercept (degrees):
LAT = -16.960
LON = -38.665
Phase angle (degrees): 48.208
Solar incidence angle (degrees): 44.387
Emission angle (degrees): 4.297
Observer visible: true
Sun visible: true
Vector: TGO NOMAD LNO Nadir Boresight
Target shape model: Ellipsoid
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2530.122
Y = -2035.307
Z = -989.188
Planetocentric coordinates of the intercept (degrees):
LAT = -16.942
LON = -38.814
Phase angle (degrees): 49.457
Solar incidence angle (degrees): 43.729
Emission angle (degrees): 6.086
Observer visible: true
Sun visible: true
Local Solar Time at boresight intercept (24 Hour Clock):
14:51:36
Target shape model: DSK/Unprioritized
Position vector of surface intercept in the IAU_MARS frame (km):
X = 2530.471
Y = -2035.529
Z = -989.307
Planetocentric coordinates of the intercept (degrees):
LAT = -16.942
LON = -38.813
Phase angle (degrees): 49.457
Solar incidence angle (degrees): 44.387
Emission angle (degrees): 5.462
Observer visible: true
Sun visible: true
Local Solar Time at boresight intercept (24 Hour Clock):
14:51:36
Extra Credit
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