I have previously written aboutISS Card Exchange TutorialThe end of the article mentioned that it was possible to exchange QSL cards with the International Space Station through a "QSL card" format. Therefore, after completing the tutorial, I performed a test myself, and the results were as follows:
Shipped
First, I found 12 other stations and collected their cards, then calculated the weight:
Based on the calculation of existing ISS QSL cards, which are approximately 10g each, 13 cards plus a return envelope would be approximately:50g self-adhesive envelopeThe limit requires a postage of 190 yen, according toJapan Post IRC exchangeThe query is available. You will need 2 IRCs. After preparing the materials, weigh them.

Total weight: 64g, according toChina Post Official WebsiteThe shipping cost is 10 yuan, so the total cost is 10 + 12 * 2 = 34. If we divide this by 12, we get approximately 2.83 per person. This is very cheap, so I plan to ship it out on October 18th for only 2.83 yuan per person.
Received
I sent out 12 QSL cards to other stations, and received 11 of them on November 22 (date with postage stamp).Someone used A4 paper to print a listening report and used it as a QSL card, but didn't respond.The attempt to complete the card collection was unsuccessful.

I also hope that we can all help each other and cooperate for mutual benefit through the "QSL card" system. I would like to provide a stable receiving address for hams who have difficulty receiving international mail, while everyone can save on postage costs.