What are the perihelion and aphelion of the Falcon Heavy second stage containing the Tesla after yesterday's mission?


2 Answers 2


It seems that Musk's tweet was erroneous, and the orbit's aphelion would be nearer 1.71 AU, instead of 2.61 AU. See Jonathan McDowell's tweet.

This agrees w/ orbit projection now shown in JPL's 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)  

The header explains the source of the data is telemetry from the 3rd stage itself, which is derived from it's GPS and other internal data:

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

Launched: 2018-Feb-06 20:45 UTC by Falcon Heavy (FH) from Kennedy Space 
       Center, USA (launchpad 39A)
  • $\begingroup$ I don't think that Musk would calculate it personally (maybe he could, but it is more likely that he pays some smart people doing such calculations in their entire life). $\endgroup$
    – peterh
    Feb 8, 2018 at 3:47
  • $\begingroup$ "I heard" do you have a source, or is this just gossip? $\endgroup$
    – user20636
    Feb 8, 2018 at 8:03
  • $\begingroup$ @JCRM good point, done. $\endgroup$
    – uhoh
    Feb 8, 2018 at 21:49

0.98 AU and 2.61 AU. See this tweet.

enter image description here


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