RCA Corp., which had its new communications satellite disappear shortly after launch last December, said today, it would rent space on an American Telephone and Telegraph Co. satellite to accommodate cable television programmers who had planned to send their signals via the ill-fated Satcom III.

Andrew Ingliss, president of RCA American Communications Inc., said its second cable television network (CATV-2) will accomodate up to 11 channels on the AT&T Comstar satellite, although AT&T will have the right to pre-empt use of the channels at any time.

RCA still does not know what happened to the $20 million satellite it launched from Cape Canaveral on Dec. 6. The earliest it can shoot up a replacement is in June 1981, and it will be until October before that satellite can go into service. RCA will launch a Satcom IV in October 1981 that will go into service the following February.

RCA already runs a cable television network on its Satcom I satellite that beams 20 channels of programming to about 2,000 cable television stations across the United States.

Because the earth receiving equipment (the so-called earth dishes) must train on a particular satellite, RCA had to find accommodations for all 12 programmers on the same satellite or give up its notion of a second network until late 1981.

Any cable programming company that has signed up for the deceased Satcom III will be able to rent space on the AT&T satellite from RCA. RCA will pay AT&T $70,000 a month per channel while RCA's customers will pay $40,000.