¿Cuáles son las distancias de perihelio y afelio de la segunda etapa del Falcon Heavy?

Parece que el tweet de Musk fue erróneo, y el afelio de la órbita estaría más cerca de 1,71 AU, en lugar de 2,61 AU. Ver el tuit de Jonathan McDowell .

Esto concuerda con la proyección de la órbita que ahora se muestra en los Horizontes de JPL :QR= 9.86...E-01 & AD= 1.711...

2458158.500000000 = A.D. 2018-Feb-09 00:00:00.0000 TDB 
 EC= 2.688810432654559E-01 QR= 9.860573082453878E-01 IN= 1.101912591245855E+00
 OM= 3.175070416981074E+02 W = 1.772620363138233E+02 Tp=  2458153.729308890179
 N = 6.292640287243981E-01 MA= 3.002024307551933E+00 TA= 5.405918374698258E+00
 A = 1.348696130995557E+00 AD= 1.711334953745726E+00 PR= 5.720968998176613E+02

  Symbol meaning [1 au= 149597870.700 km, 1 day= 86400.0 s]:

    JDTDB    Julian Day Number, Barycentric Dynamical Time
      EC     Eccentricity, e                                                   
      QR     Periapsis distance, q (au)                                        
      IN     Inclination w.r.t XY-plane, i (degrees)                           
      OM     Longitude of Ascending Node, OMEGA, (degrees)                     
      W      Argument of Perifocus, w (degrees)                                
      Tp     Time of periapsis (Julian Day Number)                             
      N      Mean motion, n (degrees/day)                                      
      MA     Mean anomaly, M (degrees)                                         
      TA     True anomaly, nu (degrees)                                        
      A      Semi-major axis, a (au)                                           
      AD     Apoapsis distance (au)                                            
      PR     Sidereal orbit period (day)  

El encabezado explica que la fuente de los datos es la telemetría de la propia 3.ª etapa, que se deriva de su GPS y otros datos internos:

Revised: Feb 07, 2018          Tesla Roadster (spacecraft)             -143205

Tesla Roadster (Starman, 2018-017A)

Dummy payload from first launch of SpaceX Falcon Heavy launch vehicle 
consisting of a standard Tesla Roadster automobile and a spacesuit-wearing 
mannequin nicknamed Starman. 

Also includes a Hot Wheels toy model Roadster on the car's dash with a 
mini-Starman inside. A data storage device placed inside the car contains 
a copy of Isaac Asimov's "Foundation" novels. A plaque on the attachment 
fitting between the Falcon Heavy upper stage and the Tesla is etched with 
the names of more than 6,000 SpaceX employees.

After orbiting the Earth for 6 hours, a third-stage burn-to-depletion
was completed at approximately 02:30 UTC Feb 7, placing the dummy payload 
in a heliocentric orbit having a perihelion of 0.99 au and aphelion 
~1.7 au.

Payload mass: ~1250 Kg

This trajectory is a ballistic propagation derived from a post-injection 
state provided by SpaceX on 2018-Feb-7, and is based on internal GPS data. 

Prediction errors could increase significantly over time due to unmodeled
solar presure, thermal radiation, or outgassing accelerations that are not
characterized.

Launched: 2018-Feb-06 20:45 UTC by Falcon Heavy (FH) from Kennedy Space 
       Center, USA (launchpad 39A)

0,98 UA y 2,61 UA. Mira este tuit .