Spacecraft exploring the outer planets need reliable data transmission. however, the acknowledgments would take hours to arrive. this makes an ack-based reliability approach unattractive. can you think of another way to provide more reliable data transmission to spacecraft without using acknowledgments?

Use forward error correction (FEC) to perform the data transmissions. FEC is a method where you transmit the data that's been encoded with an error correction code (ECC). This adds redundancy to the data transmission which allows for some errors to be corrected upon reception without having to rely upon the sender having to send the data again. One example of an ECC is the Reed Solomon error correction code. That code is used in many different applications where retransmission of corrupted data isn't practical, such as disk sectors in hard disk drives, data encoded on optical media such as DVDs, CDs, or Blu-Ray discs. It is also frequently used for communications from satellites.