Samos (satellite)
SAMOS emerged as a more advanced satellite with additional capabilities that due to its larger mass would be launched on the Atlas-Agena booster instead of the Thor-Agena.
The US ballistic missile arsenal in 1960 consisted of a handful of Atlas ICBMs that were exposed to Soviet attack, took a long time to prepare for launch, and whose test flight record did not inspire much confidence.
Intelligence on Soviet missile activities was considered vital, but the only viable option, U-2 reconnaissance flights, had been halted by the Gary Powers shootdown in May 1960.
The initial SAMOS satellites were known as Program 101 and were merely a test model designed to verify the operability of the photo-optical camera system.
The Atlas lifted smoothly and steered downrange, as the weather was clear and cloudless, visibility was excellent and the launch vehicle could be seen until after booster section separation.
Initial jubilation at the successful launch turned to dismay when the real-time telemetry readouts showed that the nitrogen pressure gas for the Agena-A's attitude control jets was gone.
The Agena-A burn lasted 123 seconds, slightly longer than nominal, but tracking stations in VAFB, Kodiak Island, and Hawaii found no indication that orbit had been achieved, and it was concluded that the vehicle had reentered and broken up over an unknown point in the Pacific Ocean.
[6] The major objective of the SAMOS 1 mission was to determine the engineering feasibility of obtaining ground observation capability from an orbiting satellite.
It was a first-generation photo surveillance satellite intended to radio relay images back to Earth but loss of nitrogen gas pressure disrupted the guidance and control systems, causing a second stage failure.
[8] SAMOS 2 was launched from the Pacific Missile Range at 20:24:00 GMT, into a near-circular polar orbit of 474 x 557 km, 94.97 min of revolution, and 97.4° of inclination, to determine the capability for making observations of space, the atmosphere, and the nature of the globe from satellites.
Included in the instrumentation were photographic and associated test equipment, acoustical (Microphone Density Gauge) micrometeorite detection apparatus, a plasma probe, and an electric field meter.
[9] The next attempt did not take place for seven months, because of the switch to the larger Agena-B second stage that could be restarted in orbit and the operational Program 101A satellites, which had a more advanced camera system with better resolution and a wider field of view.
SAMOS 3 lifted from PALC 1-1 on 9 September 1961 at 00:00:00 GMT, was a US Air Force first-generation photo surveillance satellite with 7 instruments on board[10] but the Atlas LV-3 Agena-B booster's engines shut down after the rocket had ascended about 29 cm and it fell back onto the pad in an enormous fireball.
After SAMOS 3, it was decided to abandon the Program 101/101A satellites entirely and switch to a more conventional film recovery capsule, since the one successful mission had not proven the viability of the electro-optical camera system.
There was talk of giving the camera systems to NASA for the planetary probe program, but they were of doubtful value for taking photographs of the Moon.
As it turned out, PALC 1-1 was not seriously damaged by the explosion of SAMOS 3's booster and repair work only consisted of plumbing and electrical equipment, replacing the launcher mechanism, and cleaning and repainting.
Extensive efforts were made to ensure mission success, such as X-ray testing for bad transistors and super-clean propellant tanks.
The Atlas suffered a guidance malfunction at T+245 seconds into launch that resulted in loss of pitch control, as well as improper booster and sustainer cutoff signals.
It was believed that the improper pitch signals on SAMOS 4's launch vehicle had been caused by the accidental separation of a heat shield covering the retrorockets on the Atlas equipment pods.
Space program observers noted that this time around, the Air Force statement did report the satellite as having attained orbit.
This time, the sustainer engine did not cut off on schedule and continued operating until LOX depletion, putting the satellite into a high orbit, which resulted in the deorbit maneuver failing (although given that reentry would have taken place over densely-populated New England, this was not necessarily a bad thing).
With the loss of electrical power, the parachutes could not be deployed during reentry, and also since the retrorockets had been expended during the failed deorbit maneuver, SAMOS 5 would only leave orbit once it decayed naturally.
The Canadian authorities were suspicious that a B-52 aircraft had accidentally lost a nuclear warhead somewhere, and since this was not an easily resolved matter, the search was called off.
[14] SAMOS 6 was launched on 7 March 1962 at 19:12:00 GMT, finally had no booster problems, in part due to modifications made to the Agena-B after lessons learned from previous missions, but a series of erroneous ground commands caused the satellite to deplete its attitude control gas.
However, it was calculated that impact would occur in the Arabian Sea and in all likelihood, the cold ocean water would crack the heat shield and cause it to sink.
By the end of 1962, when the last SAMOS satellite flew, only the CORONA program had managed to return usable reconnaissance images.
Like most early space programs, SAMOS had goals that exceeded what contemporary technology was capable of, and the launch vehicles used to orbit it were nearly as marginal as the satellite itself.
Early on, the idea was to use frame readout cameras that would take a picture and send the scanned image via radio to ground stations on Earth.
[18] Sergei Khrushchev wrote in his memoirs about the partial recovery of what he believed was a SAMOS satellite, except the date, was the winter before the program started.
A second capsule was apparently recovered in early 1961, although the device had been disassembled by local farmers, exposing film and preventing the Soviets from determining the satellite's capabilities.
