It's not that they have been "unsuccessfully trying". They were not expecting to recover the previous launch vehicles. Instead, the past re-entry attempts have been entirely successful in that they have provided exactly what they expected to get out of the tests. Data.
The data from the last launch provided a lot of really crucial information that has informed design decisions made for this and following launches.
It's actually better if the next recovery fails too, at least if it happens in a way that provides really important data. This would then let them work out the engineering and science required to improve the design further.
The data from the last launch provided a lot of really crucial information that has informed design decisions made for this and following launches.
It's actually better if the next recovery fails too, at least if it happens in a way that provides really important data. This would then let them work out the engineering and science required to improve the design further.