Каковы расстояния перигелия и афелия второй ступени Falcon Heavy?

Похоже, твит Маска был ошибочным, и афелий орбиты был бы ближе к 1,71 а.е., а не к 2,61 а.е. См . твит Джонатана Макдауэлла .

Это согласуется с проекцией орбиты, которая теперь показана в JPL Horizons :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)  

В заголовке поясняется, что источником данных является телеметрия самой 3-й ступени, полученная из ее GPS и других внутренних данных:

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 а.е. и 2,61 а.е. Смотрите этот твит .