Why was there only a single Falcon 9 landing on ground-pad in 2021?
| Mittag answer (July 27) | Starship answer (Aug 7) |
|---|---|
| Whenever possible, SpaceX prefers Return To Launch Site (RTLS) landings over Autonomous Spaceport Droneship (ASDS) landings, since they get the booster back immediately instead of having to wait for a 3-day sea voyage (with all the associated dangers), marine assets are expensive to operate, and sea water is aggressively corrosive. | SpaceX prefers a landing on land rather than on the drone ship. By landing on land, they get the rocket back immmediatly, not having to wait for it's sea voyage. Also, while at sea there are always some risks (ex. rocket fals off, ship sinks, etc.). Addionally, the sea water actively destroys the rocket. Finally, the ship are expensive and time consuming to operate. |
| Also, whenever possible, SpaceX prefers to launch from Florida instead of Vandenberg, since they have many more boosters, many more facilities, many more marine assets, and much more experience with processing in Florida than they have at Vandenberg. | SpaceX also prefers to launch from Florida. They have a more advanced launchpad and more rockets. Also, they have more and better facilities. As an added plus, they have more experience launching there. And, finally, they have better ship and recovery systems. |
| The only reason to not launch from Florida is the same as the only reason to land on an ASDS: you don't have enough performance to do anything else. | The only reason not to launch from Florida is simple. The profile of the mission does not allow it. Launches from Vandenberg are necessary for most polar and retrograde orbits with a rocket that size. The same is true of land landings. Land landings take about 3 times as much fuel as drone ship landings. This is because of the added boostback burn. Unless you have a light payload, you simply don't have enough fuel for a land landing. In rare cases, there isn't even enough fuel for a water landing and the booster is expended. |
| So, the quite simplistic answer is: in 2021 there were simply (almost) no customers with light payloads to low orbits. | So, why weren't there as many land landings in 2021? Well, because very few customers had light payloads that year. Of course, the question why remains. |
| Until 2020, SpaceX was still flying Dragon v1 for the Commercial Resupply (CRS) missions to the ISS, which was light enough for an RTLS landing, however, in the middle of 2020, SpaceX switched to Cargo Dragon v2 which is too heavy for an RTLS landing. That alone accounts for a difference per year between the years before and after 2020 of 2–4 CRS missions which used to be RTLS landings in the past and are now ASDS landings. | Well, up until 2020, SpaceX was still flying there old Dragon v1 capsule. The Dragon v1 capsule is considerably lighter than the new versions. The accounted for a good portion of the land landings that year. However, during 2020, SpaceX switched to here new and improved Dragon v2 capsule. The downside was that the new capsule is too heavy for a land landing. This accounts for about 4 missions per year that changed from land to water landings. |
| The Transporter smallsat rideshare missions are either RTLS or ASDS, depending on how many and how heavy smallsats are flying on each mission. In 2021, there happened to be only one Transporter mission, likely because of CoViD-19, whereas in 2022, there were already three (of which two were RTLS landings), with a fourth one planned for November. | Additionally, in 2021 SpaceX began launching the Transporter rideshare missions. They are either land or water landings dpeneding on how many satellites are flying. If there are more it is a water landing, otherwise is a land landings. Due to the COVID-19 pandemic, there was only 1 Transporter launched in 2021. In 2022, 3 Transporter missions have already launched. Additionally one is planned for November. Out of the three that have launched, two were land landings. |
| This year, there also happened to be several National Security launches of smaller payloads that allowed an RTLS landing. The reason why those launches all happened to be bunched up this year are not fully known, but we can take two guesses: they were delayed by CoViD-19 or they were made necessary by the Russian invasion of Ukraine (or a combination of both). | There were also various small national security payloads launched this year. Most of these used land landings. While we don't why all of these national security launches were launched in such as short time period, there are two logical reasons. The first reason is that some launched were delayed by the COVID-19 pandemic. The second reason is that they were neccessiated by the russian invasion of ukraine. It is also likely that it is a combination of the two. |
| So, in 2017–2020, a significant portion of the RTLS landings were CRS missions, which however now have to be ASDS landings. The numbers for 2018 and 2019 are further inflated due to three Falcon Heavy launches resulting in 6 RTLS landings for the side boosters. (There have been no Falcon Heavy launches since.) | From 2017-2020, a significant portion of the land landings were Dragon flights, which have now become water landings. The number of landing land even higher due to Falcon Heavy flights, which cunt as three landings each. This is due to the fact that both boosters and the core are recovered. Since then, there have been no Falcon Heavy launches. |
| In 2022, we saw two Transporter launches (which didn't exist prior to 2021 and only became more regular in 2022) and three lightweight reconnaissance satellites. | In 2022, there were 2 land landing from Transporter missions. They didn't exist prior to 2021, and only became regular occurances in 2022. Additionally there were 3 launches of small national security satellites that resulted in land landings. |
| In contrast, in 2021, only 7 of the 31 launches were not Starlink or Dragon v2 launches (none of which can RTLS). Of those 7, three were interplanetary, which requires more performance, two were very heavy communications satellites in geostationary orbit, and one was a GPS satellite, which are also pretty heavy. | n 2021, only 7 out of 31 were not Starlink or Dragon launches. Neither of the two can be recovered via land landings. Of the remaining 7, 3 escaped Earth. This requires more performance and therefore can not use land landings. 2 more of them were very heavy communications satellites, and again couldn't use land landings. Finally, one had heavy GPS satellites and had the same problem. |
| Or, in short: 2021 just happened to be a year with no light satellites. | Or, the simple explanition. There weren't as many light satellites that year. |
