SpaceX in its recovery attempts can either do a Return To Launch Site (RTLS) or land downrange on an ASDS landing barge.

The Telesat 19V and 18V payloads were some of the heaviest payloads on the manifest for a single stick Falcon 9. (Falcon Heavy is for heavier payloads). The numbers appear to be aboout 7900Kg. This is much larger than the previously largest GTO orbit payload launch where they recovered the first stage downrange.

To compensate for the additional mass it seems like they have a couple of options. First off they launch to a lower GTO that requires the payload itself to migrate to GEO. This costs the payload propellant, and may take away years of service life. (Thus ArianeSpace will advertise its competitiveness since they can deliver direct to GEO, not a lower energy GTO. So while the launch might be cheaper, you waste fuel compensating.)

What I was wondering is for the heavy GTO missions, do they move the ASDS further and further downrange to recover the first stage? Thus reducing the fuel reserved for landing?

Or do they just launch to lower energy GTO to compensate? I have seen GTO-xxxx used to represent the Delta V required to get to GEO.

Someone collected the SpaceX GTO Missions information. They suggest a naming model of GTO-1500 or GTO-1800.

They define the GTO Delta V as:

GTO ΔV : The change in velocity in m/s that is required for the payload to reach GEO. A "standard" GTO insertion from Cape Canaveral, which sits at around 28.5° latitude, is GTO-1800. This means that 1800 m/s are required to reach geostationary orbit at 0° inclination.

Thus there are different orbits, that require more or less delta-v to finalize to GEO.

If you want to laugh, people have been automating screen scraping the data in the live video feed, and calculating launch/velocity/altitude profiles from that data. Here is a great example from Veebay.

Reddit Image of initial Falcon 9 flight profils

I have an updated version with a few more launches. Updated with more flights.

While looking at that, same user had a landing location visualization that is helpful for this topic.

Landing profiles

  • $\begingroup$ Ah I get you now - some of the GTO insertions are of different energies because they include inclination changes or are using a bi-elliptic insertions. Good question btw - I assume the insertion orbit would be set by the payload's mission requirements, so at the upper end of payload capacity SpaceX would be forced to move the ADSD for recovery, I don't have a source for that though! $\endgroup$
    – Jack
    Aug 6, 2018 at 19:59
  • $\begingroup$ @Jack it feels obvious, but I am curious as to the answer. On the other hand, I am thinking that recovery does not care since there is no boostback burn. Only a re-entry burn. So I guess the real question might be, do they fly a different first stage profile, which would then affect recovery location. But I am not sure. $\endgroup$
    – geoffc
    Aug 6, 2018 at 20:16
  • 2
    $\begingroup$ Probably another valuable resource from the r/spacex subreddit are the trajectories based on information from the web stream. It seems there is a different flight profile for LEO or GEO, which then defines the downrange distance of the ASDS. $\endgroup$
    – Thomas W.
    Aug 6, 2018 at 20:33
  • $\begingroup$ @ThomasW. I love that people are automating screen scraping the launch video and calculating this stuff. I can attach one that people have done this way, since it is so hilariously cool. Kremlinology to Nth degree! $\endgroup$
    – geoffc
    Aug 6, 2018 at 21:11
  • $\begingroup$ It's fantastic commitment to compile all that data! $\endgroup$
    – Jack
    Aug 6, 2018 at 21:43


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