The Oldest Functioning Government Computer Remains Located Over 25 Billion Kilometers Beyond Earth
Voyager Spacecraft's Remarkable 45-Year Journey Powered by 1970s Computers
Launched in 1977, the Voyager spacecraft, carrying six onboard computers, embarked on a mission that has spanned over four decades [1][2][3]. These computers, a combination of three custom-built types, have been instrumental in guiding the spacecraft through the vast expanse of space.
Each Voyager craft carries two 18-bit Computer Command System (CCS) processors, two 16-bit Flight Data System (FDS) processors, and two 18-bit Attitude and Articulation Control System (AACS) processors[1]. The CCS serves as the central command controller, while the FDS handles data and imaging control, and the AACS is responsible for orientation and articulation control.
The computers, designed by General Electric using CMOS and TTL integrated circuits, primarily from the Texas Instruments 7400 series, have a total onboard memory of about 32K words distributed across the six machines [1]. Despite the age and limited computing power, NASA has updated Voyager’s software remotely over the decades to address unforeseen challenges and optimize mission operations without hardware changes [2].
Operating speeds are extremely modest by modern standards, with a CPU clock rate of about 250 kHz, executing roughly 8,000 instructions per second, compared with billions per second for modern smartphones [2][3]. The Voyager’s total onboard data storage is also very limited, with about 68 kilobytes on an 8-track digital tape recorder used for scientific data accumulation and transmission back to Earth; older data is overwritten once transmitted [3].
Despite these limitations, the Voyagers continue to operate with their original 1970s hardware but updated software, providing valuable scientific data from beyond the heliopause and into interstellar space. They remain the oldest government computers still functioning and the farthest human-made objects from Earth [2][3][4].
| Computer Type | Bits | Number per craft | Memory (words) | Function | |---------------------------------|------|------------------|---------------------|---------------------------------| | Computer Command System (CCS) | 18 | 2 | 4,096 non-volatile | Central command/control | | Flight Data System (FDS) | 16 | 2 | 8,198 modular | Data handling, imaging control | | Attitude and Articulation (AACS) | 18 | 2 | 4,096 | Orientation/attitude control |
All three computer types utilize proprietary, space-hardened hardware and operate largely non-redundantly to maximize capability, with one backup unit for each type [1][2]. The mission depends on robust original design and clever software management, as no hardware upgrades have been made since launch due to the impossibility of physical servicing.
The Voyager mission is expected to continue, albeit with occasional shutdowns of its instruments, until it finally powers down in the 2030s. Despite this, Voyager, and one of our oldest government computers, will still have a long journey ahead of it after it powers down. NASA uses the tiny storage of Voyager's computers to get back useful science data from beyond the Solar System's 30,000-50,000 Kelvin "wall". The flight data subsystem of Voyager can handle imaging data at six different downlink rates, with the standard full-frame readout taking 48 seconds per frame.
References: 1. Voyager Spacecraft 2. Voyager Spacecraft's Computers 3. Voyager Spacecraft's Onboard Computers 4. Voyager's Journey Through Interstellar Space
- The Voyager spacecraft, featuring 1970s technology, has remarkably continued its mission in space for over four decades, with data and scientific information now being accumulated beyond the heliopause and into interstellar space.
- Engineering advancements in the 1970s led to the creation of space-hardened hardware like the Computer Command System (CCS), Flight Data System (FDS), and Attitude and Articulation Control System (AACS) processors, which are still operational on the Voyagers today.
- As we progress in science, we strive to leverage data-and-cloud-computing technologies to glean more insights from the valuable scientific data being sent back by the Voyagers, despite their limited onboard storage and computing power.
