Questions tagged [spice]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
2
votes
0answers
27 views

Lunar eclipses using SPICE toolkit, missing ephemeris data

I want to figure out lunar eclipses as seen from a point on the Moon using SPICE. To generate ephemeris for the point on the Moon, I use the code provided in this answer. Instead of ...
2
votes
0answers
25 views

determining lunar eclipse with SPICE toolkit

Is there any way to determine if the Sun is visible from the Moon at a given latitude/longitude and at a given instant in SPICE toolkit? Specifically, determine if there is lunar eclipse or transit ...
3
votes
1answer
71 views

SPICE defining a topocentric frame on the Moon

I would like to define a topocentric frame for a particular spot on the moon. From the frames required reading i have this: ...
3
votes
1answer
121 views

Horizons ephemeris - how did they calculate that “Keplerian GM” value?

I’ve been playing with the NAIF’s SPICE library for some time (CSPICE in particular). In order to obtain the state vector of an asteroid from its osculating elements, I’m calling the “conics_c” ...
2
votes
1answer
108 views

How to get MARS2020/Perseverance EDL trajectory data from spice kernels?

For MSL EDL it is available this answer: How to retrieve MSL EDL trajectory using Javascript and webgeocalc API? How can I adapt it to MARS2020/Perseverance?
3
votes
1answer
49 views

Does SPICE function gftfov account for occultations?

I need to determine when an antenna on a spacecraft can see a ground station on Earth at particular epochs. I have generated all the necessary SPICE kernels necessary as well as using the NASA ...
1
vote
1answer
160 views

Was the famous SPICE package of programs, utilities and data kernels named after “Melange” found on the planet Arrakis?

This question is NOT about a fictional planet: This question is about NASA JPL history and the naming of SPICE. It is not primarily about the fictional planet Arrakis nor the fictional drug Melange ...
2
votes
1answer
87 views

How to retrieve MSL EDL trajectory using Javascript and webgeocalc API?

I found a "javascript gateway" to NASA SPICE data, the "webgeocalc" web api: https://wgc2.jpl.nasa.gov:8443/webgeocalc/example/perform-calculation.html It works both online and ...
3
votes
0answers
50 views

How to get MSL coordinates during EDL from SPICE kernel?

Upon trying to extract MSL position above surface by decoding a SPICE kernel, I am gettin this error: At epoch 3.9750216818313E+08 TDB (2012 AUG 06 05:16:08.183 TDB), there is insufficient ...
4
votes
2answers
314 views

How to convert a SPICE SPK kernel into human-readable data using SPICE toolkit and utilities

SPK2OEM is one of many of SPICE tools available here: https://naif.jpl.nasa.gov/naif/utilities_PC_Windows_32bit.html I am trying to extract ephemeris from one of the SPK files listed here: https://...
3
votes
1answer
89 views

Should coordinate transformations from J2000 to ITRF93 in quaternions be cyclic?

I used SPICE's pxform at an interval of epochs to determine the transformation from J2000 (inertial) to ITRF93 (Earth body-fixed) frame. Then, I converted these rotation matrices to quaternions with ...
4
votes
1answer
72 views

How can I generate Chebyshev cofficients from SPICE for J2000 Inertial to Moon ME Frame?

I want to extract the Chebyshev coefficients in order to be able to calculate the time-varying transformation from the ICRF / J2000 Inertial frame to the Moon ME (moon mean earth) frame. I know I can ...
2
votes
1answer
135 views

Rotation matrix from J2000 to ITRF2008

I want to rotate a vector from the inertial J2000 frame into ITRF2008. I am using the NASA SPICE library, which provides a rotation matrix from J2000 to ITRF93 (they plan to upgrade the library to a ...
3
votes
0answers
105 views

Suggestion for software which allows orbit data generation under different conditions (such as J2, ATM drag etc)

I am an amateur astrophysics enthusiast trying to generate orbit data. What I want to achieve: I want to be able to generate orbits while only considering effects of (J2, J3, atm drag, solar ...
3
votes
2answers
335 views

How to obtain Chebyshev coefficients directly from the JPL Horizon's interface?

I'm from Spain and I'm currently finishing my degree in Aerospace Engineering. I am starting with all of this. My objective is to obtain the Chebyshev coefficients for the major planets position, ...
4
votes
0answers
133 views

SPICE GFPOSC is returning incorrect sunrise (and sunset) times for topocentric frames

I cannot get SPICE to produce accurate sunrise times for topocentric frames I specify. I'm using spiceypy to interface with SPICE. As a first test, I set up topo coordinates for the MARE landing site,...
3
votes
1answer
149 views

How does one use SPICE to compute the Greenwich sidereal time as an angle?

I'm looking at the BMW book† and see that equation 7.5-7 gives $\alpha_0 = \theta = \theta_g + \lambda_E$ as the equation for right ascension (for some launch site at east longitude $\lambda_E$). $\...
1
vote
0answers
175 views

How to define a body-centered ICRF/J2000 frame in SPICE?

I am trying to define a reference frame in SPICE that is Centered on a particular body, for example Mars, and with axes parallel to J2000/ICRF After going through the required reading for reference ...