I asked the Tello/DJI/RYZE support and I got following answer:
“[…]
In regards to your concern that you can't find the Tello Space Travel course, the said course has not be maintained anymore in Swift Playgrounds V4. However, kindly follow the details below.
TELLO EDU supports graphical programming by TELLO EDU APP on mobile device: Mind+ and python programming on PC.
TELLO EDU APP: download in APP store
mind+: http://mindplus.cc/download-en.html
python: In respect to SDK issues of tello edu, please send to […] for consultation, our engineer will reply you during 1-3 workdays.
[…]“