ALOHA and its variants [3]. However, in the CSMA protocol, each piece of SUE cannot monitor neighboring SUE and becomes a hidden terminal to them. Additionally, due to the long-distance propagation between satellites and SUE, each piece of SUE needs to listen for a long time before transmission. Therefore, CSMA becomes ineffective in satellite communications. By considering the listening duration and the random transmission of the vanilla ALOHA protocol, future multiple access protocols for satellite communications are expected to be based on Slotted ALOHA [4]. The Slotted ALOHA (SA) protocol is a classic variant of ALOHA and is widely used in wireless networks. It discretizes time, resulting in a lower collision probability compared with the ALOHA protocol. In the field of satellite communications, channel utilization of satellite devices is of great interest. In [5], the Diversity Slotted ALOHA (DSA) protocol, which slightly improved the channel utilization of SA by introducing burst repetition under low-load conditions, was proposed. In [6], Contention Resolution Diversity Slotted ALOHA (CRDSA), which further improved system channel utilization by introducing interference cancellation techniques, was proposed. Building on this, [7] proposed IRSA, which made the number of burst repetitions random, increasing the theoretical maximum channel utilization to 97%, with an actual utilization of 80%, while SA achieves only 37%. Although the IRSA algorithm significantly improves channel utilization, it still has three unresolved issues. First, the frame size: The maximum channel utilization of the IRSA algorithm is proportional to the frame size. The more slots a frame contains, the higher the channel utilization. For example, achieving 80% channel utilization requires a frame to contain about 1000 slots for access, resulting in excessively long frame times. Additionally, the performance of the IRSA algorithm degrades significantly under high channel load, with channel utilization even lower than Slotted ALOHA. Finally, the IRSA algorithm still results in 20% channel resource waste in practical use. It is worth noting that time delay issues caused by long-distance propagation in satellite communications further exacerbate the performance bottlenecks of existing protocols. Studies on spacecraft control systems have shown that unbounded input time delay can severely affect dynamic response stability. The integrated predictor-observer feedback control strategy, which provides important insights for handling communication time delays by synchronously estimating system states and disturbances and incorporating a predictor to compensate for time delays, was proposed in [8]. To address the above issues, this paper proposes the Separated Transmission and Control IRSA (STCA) protocol. This protocol separates transmission and access control functions, deploying the access control process on airborne access control nodes (ACNs) to form an integrated space-air-ground network. Specifically, SUE first accesses ACNs closer to the ground and, after successful access, directly transmits information to the satellite. In this way, collisions only occur at ACNs, thereby maximizing satellite channel utilization. By offloading access control to ACNs close to the ground, the access interaction distance for SUE is shortened, reducing the transmission delay of control signaling; meanwhile, the load estimation and control algorithms mitigate the impact of load fluctuations caused by time delays by dynamically adjusting access probabilities, which echoes the idea in [8] that \"time delay compensation should be combined with dynamic adjustments\". In addition, due to the separation of transmission and access control processes, access data packets contain only a small amount of information, and the access process uses minislots as access slots, which addresses the issue of excessively long frame times in IRSA caused by the need for a large number of slots. Simulation results show that the proposed STCA outperforms IRSA in terms of channel utilization.