Results: In formulating a series of early scientific missions to Venus, in early 1961, NASA originally planned two missions, P-37 and P-38, to be launched on Atlas Centaur rockets, each spacecraft weighing about 565 kilograms. By the time NASA Headquarters formally approved the plan in September 1961, problems with the Atlas Centaur necessitated a switch to the Atlas Agena B with a reduced payload. By that time, JPL prepared three spacecraft based on the design of the Ranger Block I series (therefore named Mariner R) to fly by Venus in late 1962. Each spacecraft carried a modest suite (9 kilograms) of scientific instrumentation, but had no imaging capability. The spacecraft included 54,000 components and was designed to maintain contact with Earth for 2,500 hours—an ambitious goal given that the (still unsuccessful) Ranger was designed for only 65 hours contact. Mariner I would have flown by Venus at range of 29,000 kilometers on 8 December 1962 but due to an incorrect trajectory during launch, at T+294.5 seconds, range safety sent a signal to destroy the Atlas booster and its payload. The failure was traced to a guidance antenna on the Atlas as well as faulty software in its onboard guidance program, which was missing a single superscript bar. The press described it as "the most expensive hyphen in history."
28 [Venera, 2MV-1 no. 3]
- Nation: USSR (14)
- Objective(s): Venus impact
- Spacecraft: 2MV-1 (no. 3)
- Spacecraft Mass: 1,097 kg (350 kg impact capsule)
- Mission Design and Management: OKB-1
- Launch Vehicle: Molniya + Blok L (8K78 no. T103-12)
- Launch Date and Time: 25 August 1962 / 02:56:06 UT
- Launch Site: NIIP-5 / Site 1/5
Scientific Instruments:
Spacecraft Bus:
- magnetometer
- scintillation counter
- gas discharge Geiger counters
- Cherenkov detector
- ion traps
- cosmic wave detector
- micrometeoroid detector
Impact Probe:
- temperature, pressure, and density sensors
- chemical gas analyzer
- gamma-ray detector
- Mercury level wave motion detector
Results: This was the first of a second generation of Soviet deep space probes based on a unified platform called 2MV ("2" for the second generation, "MV" for Mars and Venera) designed to study Mars and Venus. The series included four variants with the same bus but with different payload complements: 2MV-1 (for Venus impact), 2MV-2 (for Venus flyby), 2MV-3 (for Mars impact), and 2MV-4 (for Mars flyby). The buses were basically similar in design carrying all the essential systems to support the mission as well as a main engine, the S5.17 on the two Venus probes, and the S5.19 on the Mars probes. Both had a thrust of 200 kgf but the former was capable of one firing while the latter was designed for two. The payloads were designed in two variants depending on whether the mission was a flyby mission or an impact mission. In the former, there was an instrument module, and in the latter, it carried a 90-centimeter diameter spherical pressurized lander covered by thermal coating; the Venus landers were cooled with an ammonia-based system, while the Mars landers used a system of air conditioners. Both landers were sterilized with a special substance on recommendation from the Academy of Sciences' Institute of Microbiology. The buses were powered by solar panels with an area of 2.5 m² capable of providing 2.6 A. The Venus impact probes were to use a three-stage parachute system to descend through the atmosphere. For Venus, the Soviets prepared three spacecraft for the August–September 1962 launch period, one flyby spacecraft and two landers. This first spacecraft—a flyby plus lander combination—was successfully launched into Earth orbit, but the Blok L upper stage cut off its interplanetary burn after only 45 seconds (instead of the planned 240 seconds). Later investigation showed that the stage had been set on a tumbling motion prior to main engine ignition due to asymmetrical firing of the solid propellant stabilizing motors. The spacecraft remained in Earth orbit for three days before reentering Earth's atmosphere.
29 Mariner II
- Nation: USA (15)
- Objective(s): Venus flyby
- Spacecraft: P-38 / Mariner R-2
- Spacecraft Mass: 203.6 kg
- Mission Design and Management: NASA / JPL
- Launch Vehicle: Atlas Agena B (Atlas Agena B no. 6 / Atlas D no. 179 / Agena B no. 6902)
- Launch Date and Time: 27 August 1962 / 06:53:14 UT
- Launch Site: Cape Canaveral / Launch Complex 12
NASA image showing mission planners receiving data from Mariner II in January 1963, about five months after its launch. Note the reference to current tracking by the NASA station in South Africa. Credit: NASA
Image
This 1961 photo shows Dr. William H. Pickering, (center) JPL Director, presenting a Mariner spacecraft model to President John F. Kennedy, (right). NASA Administrator James Webb is standing directly behind the Mariner model. Credit: NASA
Scientific Instruments:
- microwave radiometer
- infrared radiometer
- fluxgate magnetometer
- cosmic dust detector
- solar plasma spectrometer
- energetic particle detectors
- ionization chamber
Results: NASA brought the Mariner R-2 spacecraft out of storage and launched it just 36 days after the failure of Mariner I. Mariner II was equipped with an identical complement of instrumentation as its predecessor (see Mariner I). The mission proved to be the first fully successful interplanetary mission performed by any nation. After a mid-course correction on 4 September, the spacecraft flew by Venus at a range of 34,854 kilometers at 19:59:28 UT on 14 December 1962. During a 42-minute scan of the planet, Mariner II gathered significant data on the Venusian atmosphere and surface before continuing on to heliocentric orbit. The radiometers, in particular, were able to conduct five scans of the nightside of the planet, eight across the terminator, and five on the daylight side. NASA maintained contact until 07:00 UT on 3 January 1963 when the spacecraft was 86.68 million kilometers from Earth, a new distance record for a deep space probe. The data returned implied that there was no significant difference in temperature across Venus: readings from Mariner II's microwave radiometer indicated temperatures of 216°C (on the dark side) to 237°C (on the day side). Mariner II also found that there was a dense cloud layer that extended from 56 to 80 kilometers above the surface. The spacecraft detected no discernable planetary magnetic field, partly explained by the great distance between the spacecraft and the planet. If in terms of scientific results, Mariner II was only a modest success, it still retains the honor of being the very first successful planetary science mission in history. NASA elected to stand down the third spacecraft in the series (Mariner R-3) scheduled for the 1964 launch period.
30 [Venera, 2MV-1 no. 4]
- Nation: USSR (15)
- Objective(s): Venus impact
- Spacecraft: 2MV-1 (no. 4)
- Spacecraft Mass: c. 1,100 kg (370 kg impact capsule)
- Mission Design and Management: OKB-1
- Launch Vehicle: Molniya + Blok L (8K78 no. T103-13)
- Launch Date and Time: 1 September 1962 / 02:12:33 UT
- Launch Site: NIIP-5 / Site 1/5
Scientific Instruments:
Spacecraft Bus:
- magnetometer
- scintillation counter
- gas discharge Geiger counters
- Cherenkov detector
- ion traps
- cosmic wave detector
- micrometeoroid detector
Impact Probe:
- temperature, pressure, and density sensors
- chemical gas analyzer
- gamma-ray detector
- Mercury level wave motion detector
Results: This was the second of three Venus spacecraft launched by the Soviets in 1962. Like its predecessor launched in August 1962 (also a Venus impact probe), the spacecraft never left parking orbit around Earth due to a malfunction in the Blok L upper stage designed to send the probe out of Earth orbit towards Venus. The valve that controlled the delivery of fuel into the combustion chamber of the Blok L engine (the S1.5400) never opened. As a result, the engine did not fire. The payload decayed within five days of launch.
31 [Venera, 2MV-2 no. 1]
- Nation: USSR (16)
- Objective(s): Venus flyby
- Spacecraft: 2MV-2 (no. 1)
- Spacecraft Mass: [unknown]
- Mission Design and Management: OKB-1
- Launch Vehicle: Molniya + Blok L (8K78 no. T103-14)
- Launch Date and Time: 12 September 1962 / 00:59:13 UT
- Launch Site: NIIP-5 / Site 1/5
Scientific Instruments:
Spacecraft Bus:
- magnetometer
- scintillation counter
- gas discharge Geiger counters
- Cherenkov detector
- ion traps
- cosmic wave detector
- micrometeoroid detector
Instrument Module:
- imaging system
- ultraviolet spectrometer
- infrared spectrometer
Results: Like its two predecessors (launched on 25 August and 1 September 1962), this Soviet Venus probe never left parking orbit around Earth. The Blok L upper stage designed to send the spacecraft towards Venus fired for only 0.8 seconds before shutting down due to unstable attitude. Later investigation indicated that the upper stage had been put into a tumble due to the violent shutdown (and destruction) of the third stage (Blok I) between T+530.95 and T+531.03 seconds. The tumble mixed air bubbles within the propellant tanks preventing a clean firing of the engine. Unlike its predecessors, this probe was designed for a Venus flyby rather than atmospheric entry and impact. The payload reentered two days after launch.
32 Ranger V
- Nation: USA (16)
- Objective(s): lunar impact
- Spacecraft: P-36
- Spacecraft Mass: 342.46 kg
- Mission Design and Management: NASA / JPL
- Launch Vehicle: Atlas Agena B (Atlas Agena B no. 7 / Atlas D no. 215 / Agena no. 6005)
- Launch Date and Time: 18 October 1962 / 16:59:00 UT
- Launch Site: Cape Canaveral / Launch Complex 12
Scientific Instruments:
- imaging system
- gamma-ray spectrometer
- single-axis seismometer
- surface-scanning pulse radio experiment
Results: This was the third attempt to impact the lunar surface with a Block II Ranger spacecraft. On this mission, just 15 minutes after normal operation, a malfunction led to the transfer of power from solar to battery power. Normal operation never resumed, and battery power was depleted after 8 hours, following which all spacecraft systems died. The first mid-course correction was never implemented, and Ranger V passed the Moon at a range of 724 kilometers on October 21 and entered heliocentric orbit. It was tracked to a distance of 1,271,381 kilometers. Before loss of signal, the spacecraft sent back about 4 hours of data from the gamma-ray experiment.
33 [Mars, 2MV-4 no. 3]
- Nation: USSR (17)
- Objective(s): Mars flyby
- Spacecraft: 2MV-4 (no. 3 or no. 1)
- Spacecraft Mass: c. 900 kg
- Mission Design and Management: OKB-1
- Launch Vehicle: Molniya + Blok L (8K78 no. T103-15)
- Launch Date and Time: 24 October 1962 / 17:55:04 UT
- Launch Site: NIIP-5 / Site 1/5
Scientific Instruments:
- magnetometer
- 2 scintillation counters
- 2 gas discharge Geiger counters
- Cherenkov counter
- 2 ion traps
- infrared spectrometer
- micrometeoroid sensor
- imaging system
- ultraviolet spectrograph
Scientific experiments on the Ranger Block II spacecraft. Credit: NASA
Results: This was the first of three "second generation" interplanetary probes (two flyby probes and one impact probe) designed to reach Mars prepared by the Soviets for the late 1962 launch period. Because of the repeated failures of the Blok L upper stage during deep space missions, engineers elected to outfit the stage for the Mars missions with supplementary control and measurement equipment. As a result, most of the scientific instruments were deleted from the Mars spacecraft. The three missions were primarily technological test flights rather than scientific missions. In this case, the Blok L interplanetary stage failed again. Just 17 seconds after trans-Mars injection ignition, the turbopump of the main engine (the S1.5400A1) exploded, destroying the payload. The problem was traced to leaking lubricant. As many as 24 fragments were later tracked in 1,485 × 180-kilometer orbit at 64.8° inclination, the largest of which reentered on 29 October. The original probe was designed to fly by Mars on 17 June 1963.