The Apollo Telescope Mount (ATM) was a solar observatory launched with the Skylab space station. It was launched attached to the station's Fixed Airlock Shroud (FAS), aligned with the station's axis and with solar arrays folded. In orbit it remained attached to the station and was rotated 90 degrees from the station's axis.

This rotation cleared the access to the station's primary docking port. It also allowed the solar arrays to be deployed clear of the station.

Although the ATM was integrated with the Skylab station, it started as a separate project related to use of the Apollo spacecraft, which is why it has the name Apollo in it rather than Skylab.

ATM References: Wikipedia  |  Historic Spacecraft

Design

The ATM included a number of telescopes to observe our Sun. It consisted of an octagonal structure 3.3m in diameter and 4.2m long. Inside was a cylindrical canister, 2.1m in diameter and 3m long, divided into four quadrants. Each quadrant contained equipment for solar experiments. The canister was gimbaled, to allow very fine pointing control for the sensitive instruments. When not in use, each instrument was protected by a moveable aperture door.

The ATM had a total weight of 11,092 kg and contained three control moment gyros (CMG) to help stabilize it during operation. It was powered by four solar arrays, spaced equally around the outer structure, with a total span of 29.4m. The ATM arrays were also used to supplement the station's power, as it only had one operational array.

Operation

The ATM observed the Sun in wavelengths ranging from soft X-rays, ultraviolet, and visible light. It was manually operated by the astronauts using the Command and Display (C&D) console in Skylab's Multiple Docking Adapter (MDA).

Most of the data was collected on exposed photographic film. The film magazines were changed out by the crew during spacewalks and returned to Earth with the crew. Some instruments had a live video feed that could be observed from inside the space station on a CRT video screen. Polaroid photos (an instant film-to-hard copy camera) ware also taken of the CRT screen.

The Skylab station was maneuvered to point the ATM at the Sun. The station also was able to use power from the ATM solar arrays.

Experiments

Solar experiments mounted in the ATM included:

• S-056 X-Ray telescope
• S-054 X-Ray telescope
• S-082A Extreme Ultraviolet Spectroheliograph
• S-082B Ultraviolet Spectrograph
• S-020 X-ray and extreme ultraviolet camera
• S-055 Ultraviolet Spectroheliometer
• S-052 White Light Coronagraph
• H-alpha no. 1 Hydrogen-Alpha Telescope
• H-alpha no. 2 Hydrogen-Alpha Telescope