Questions tagged [spice]

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How to convert a SPICE SPK kernel into human-readable data (CCSDS “Orbit Ephemeris Message”) using spk2oem tool

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
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1answer
29 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
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1answer
43 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
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1answer
81 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
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0answers
102 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
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2answers
263 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, ...
3
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0answers
109 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
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1answer
109 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
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0answers
141 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 ...