According to The Sum Of All Knowledge, the Falcon 9 has only twice (including the 2016 ground fire destroying the payload) failed to put the primary payload in orbit.

Thus, the May 30 2020 Demo-2 launch seemed pretty boring/routine. Was there something special about the rocket (not the payload; just the launcher)?

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    $\begingroup$ What makes you think it was different? $\endgroup$
    – Moo
    May 30, 2020 at 23:30
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    $\begingroup$ Edited the question for timelessness and clarity. $\endgroup$ May 31, 2020 at 1:16
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    $\begingroup$ By way of analogy, consider what will happen when a vaccine against COVID-19 is finally released to the public. The cheers for that release will be much louder than were the cheers for this very important launch. Yet the public release of that vaccine will seem pretty boring / routine because by that point it has to be. Any changes in the vaccine would entail taking several steps back. The released vaccine will be exactly the same as what was tested in multiple prior phases of clinical trials. The public release will represent the culmination of that prior work, and will be widely cheered. $\endgroup$ May 31, 2020 at 15:00
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    $\begingroup$ Completing the analogy, the launch on Saturday represented the culmination of a decade's worth of prior work. During that decade, SpaceX had to make modifications to the Falcon 9 to make it safe for humans and then prove to NASA that it was indeed safe for humans. One small part of that was to make Falcon 9 launches at least appear to be boring / routine. $\endgroup$ May 31, 2020 at 15:13
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    $\begingroup$ @uhoh - Some questions are worth downvoting. This is one of them. $\endgroup$ Jun 1, 2020 at 4:30

2 Answers 2


There was no significant difference between the Falcon 9 booster (first stage B1058, on its first flight, as it happened) used for Demo-2 and other Block 5 Falcons.

The excitement was entirely due to the fact of it having a crewed payload, the first NASA astronauts to launch on a US rocket on US soil since 2011.

While Falcon 9 is shaping up to be a quite reliable launcher, no rocket launch is anything like perfectly safe; the stakes for the May 30 launch were higher than usual, and given the way the year is going, many people were braced for some kind of disaster to occur. For those people, there was a significant sense of relief after the first stage and second stage phases of the ascent completed. This sense was particularly acute for people of my age cohort, who were school-aged when the Challenger accident occurred in 1986; many of my friends commented on the tension they felt watching this launch.

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    $\begingroup$ Its worth noting that NASA needed stability in Falcon 9 configurations for a certain number of launches before they would sign off on a crewed launch, hence the rapid development up to Block 5 and then a plateau $\endgroup$
    – Moo
    May 31, 2020 at 1:53
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    $\begingroup$ Yes: Crewed payload. Adding to the tension was that just a day or two earlier a different commercial space/rocket company had a static test engine perform an unscheduled rapid disassembly (shortly after the test) in an a very exciting way. Safe as we'd all like them to be rocket launches aren't entirely safe yet. I distinctly remember the shock and numbness I felt passing as store in Central Square, Cambridge, MA and seeing a jagged trail on a TV in there on a day I knew the Challenger was launching. $\endgroup$
    – davidbak
    May 31, 2020 at 18:47
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    $\begingroup$ @davidbak If you are referring to Starship and its explosion the day before, that one is also a SpaceX rocket, a different design meant to go straight to Mars. $\endgroup$
    – walen
    Jun 1, 2020 at 7:02
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    $\begingroup$ @RonJohn you don’t understand the mentality of Americans being exited about launching American astronauts on an American rocket from America? $\endgroup$
    – Tim
    Jun 1, 2020 at 8:39
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    $\begingroup$ @Tim I'm an American, and I'm very glad the US finally is launching it's own people again instead of needing to go hat in hand to the Russians. It's been grossly over-hyped, though. "Unprecedented achievement", etc, etc. Yes, things are different now (reusable first stage and capsule), but sending men to orbit in a capsule on top of a rocket has quite a lot of precedent. The booster landing four years ago was unprecedented, as was the booster reuse three years ago. This, though? Lots of precedent.) $\endgroup$
    – RonJohn
    Jun 1, 2020 at 13:16

There were a number of minor upgrades that had to happen, primarily to allow for automatic flight failure detection to allow the abort system to activate. These fly on every flight now, but they didn't in the past. Past systems have included a wire that runs the length of the booster to detect if there is a fault, and there is almost certainly some software upgrades to detect issues, although I haven't been able to find the specific changes.

The biggest difference is not so much the booster, but the flight profile. In order to get humans to the ground safely in the event of an abort, a shallow trajectory is required. This results in a less fuel efficient trajectory, most noted by the booster having to land on a barge, while they could have launched the spacecraft in to a less abort friendly orbit and returned to the launch site. You can see the difference between a cargo dragon and a crew dragon at this site.

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  • $\begingroup$ Any detail on those "minor upgrades"? $\endgroup$
    – Mike Wise
    Jun 1, 2020 at 10:26
  • $\begingroup$ I don't have any specifics, but they usually include running a wire the length of the rocket to detect breakup and software changes associated with this. Falcon 9 has an autonomous flight safety system, which is probably quite similar in a number of ways, so... $\endgroup$
    – PearsonArtPhoto
    Jun 1, 2020 at 12:55
  • $\begingroup$ Can you provide references for the "a shallow trajectory is required"? AFAIK starliner from boeing will certainly do a shallow trajectory; Crew Dragon, last I've heard, actually does a steeper profile, bringing astronauts to orbit as fast as possible. I've tried to find some official sources but I cannot find any document specifying the flight profile one way or the other. $\endgroup$
    – Bakuriu
    Jun 1, 2020 at 15:01
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    $\begingroup$ It is a shallower trajectory, because otherwise they would do a RTLS for the booster. They have to be shallower to support an abort at any time, if you go straight up it's really hard to slow down quick enough, to slow down via atmosphere you have to spread it out a bit. $\endgroup$
    – PearsonArtPhoto
    Jun 1, 2020 at 15:11
  • $\begingroup$ This doesn't seem right. I read before that DM-2 has a steeper profile, not a shallower one, compared to crew dragon missions. I don't know exactly why: I can think of different factors, and some seem to favor a steep trajectory and some a shallow. I think Everyday Astronaut switched the profiles. See the profiles on flightclub.io: CRS-20 climbs to about 160 km (flightclub.io/result/2d?id=0ebad692-0e09-44f0-a610-ec6568bfa95d), while DM-2 climbs to 216 km (flightclub.io/result/2d?code=DEM2) $\endgroup$ Jun 2, 2020 at 9:00

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