Physical Constants and Bodies

def bodvrd(bodynm: str, item: str, maxn: int) -> Tuple[int, ndarray]:
    """
    Fetch values from kernel pool for a body.
    
    Parameters:
    - bodynm: str, body name
    - item: str, property name ("RADII", "GM", "J2", etc.)
    - maxn: int, maximum number of values to return
    
    Returns:
    Tuple[int, ndarray]: (n, values) - number of values and array of values
    """

def bodn2c(name: str) -> int:
    """
    Translate body name to NAIF integer ID code.
    
    Parameters:
    - name: str, body name
    
    Returns:
    int: NAIF ID code
    """

def bodc2n(code: int) -> str:
    """
    Translate NAIF integer ID code to body name.
    
    Parameters:
    - code: int, NAIF ID code
    
    Returns:
    str: body name
    """

def spd() -> float:
    """
    Return seconds per day.
    
    Returns:
    float: 86400.0 (seconds per day)
    """

def rpd() -> float:
    """
    Return radians per degree.
    
    Returns:
    float: π/180 (radians per degree)
    """

def dpr() -> float:
    """
    Return degrees per radian.
    
    Returns:
    float: 180/π (degrees per radian)
    """

def pi() -> float:
    """
    Return the value of pi.
    
    Returns:
    float: π
    """

def halfpi() -> float:
    """
    Return the value of pi/2.
    
    Returns:
    float: π/2
    """

def twopi() -> float:
    """
    Return the value of 2*pi.
    
    Returns:
    float: 2π
    """

import spiceypy as spice

spice.furnsh("pck00010.tpc")  # Load planetary constants kernel

# Get Earth's radii
n, radii = spice.bodvrd("EARTH", "RADII", 3)
print(f"Earth radii: {radii} km")

# Get Mars GM (gravitational parameter)
n, gm = spice.bodvrd("MARS", "GM", 1) 
print(f"Mars GM: {gm[0]} km^3/s^2")

spice.kclear()

# Convert names to NAIF IDs
earth_id = spice.bodn2c("EARTH")
mars_id = spice.bodn2c("MARS")
print(f"Earth ID: {earth_id}, Mars ID: {mars_id}")

# Convert IDs back to names
earth_name = spice.bodc2n(399)
print(f"Body 399: {earth_name}")