Mission type | Lunar impactor | ||||
---|---|---|---|---|---|
Operator | NASA / JPL | ||||
COSPAR ID | 1964-041A | ||||
SATCAT no. | 00842 | ||||
Mission duration | 2 days, 20 hours and 35 minutes | ||||
Spacecraft properties | |||||
Manufacturer | Jet Propulsion Laboratory | ||||
Launch mass | 365.6 kg (806 lb) [1] | ||||
Dimensions | 1.52 m × 2.51 m (5.0 ft × 8.2 ft) | ||||
Power | 200 W | ||||
Start of mission | |||||
Launch date | July 28, 1964, 16:50:07UTC [1] | ||||
Rocket | Atlas LV-3 Agena-B (250D / AA9) | ||||
Launch site | Cape Canaveral, LC-12 | ||||
Lunar impactor | |||||
Impact date | July 31, 1964, 13:25:48.82 | UTC||||
Impact site | 10°38′02″S20°40′38″W / 10.6340°S 20.6771°W [2] (Between Mare Nubium and Oceanus Procellarum) | ||||
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Ranger 7 was the first NASA space probe to successfully transmit close-up images of the lunar surface back to Earth. It was also the first completely successful flight of the Ranger program. Launched on July 28, 1964, Ranger 7 was designed to achieve a lunar-impact trajectory and to transmit high-resolution photographs of the lunar surface during the final minutes of flight up to impact.
The spacecraft carried six television vidicon cameras—two wide-angle (channel F, cameras A and B) and four narrow-angle (channel P)—to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality video pictures. Ranger 7 transmitted over 4,300 photographs during the final 17 minutes of its flight. After 68.6 hours of flight, the spacecraft impacted between Mare Nubium and Oceanus Procellarum. This landing site was later named Mare Cognitum. The velocity at impact was 2.61 kilometers per second (1.62 mi/s), and the performance of the spacecraft exceeded hopes. [3] No other experiments were carried on the spacecraft. [4]
Although NASA had attempted to put a positive spin on Ranger 6 on the grounds that everything except the camera system had worked well, William J. Coughlin, editor of the publication Missiles and Rockets, called it a "one hundred percent failure" and JPL's record thus far was "a disgrace". The mission had not been a complete failure, but Coughlin was not alone in his opinion that Jet Propulsion Laboratory in Pasadena, California, a nonprofit laboratory and extension of the California Institute of Technology (Caltech), was a "soft" academic environment without the drive or ambition needed to make the missions succeed. He considered Ranger a "loser" and for a while, anyone at NASA involved in the Ranger program tried to conceal it. It was also being said that sending probes up for the sole purpose of returning images was pointless and accomplished nothing that Apollo could not also achieve. [5]
Shortly after Ranger 6's mission concluded a review board was convened to resolve the cause of the TV camera failure. This was determined quickly; the inadvertent activation of the camera telemetry system during ascent had been caused by an electrical short that crippled the power supply for the cameras. But why it had happened was as yet a mystery, especially as telemetry data sent back from the probe could only provide a limited amount of information. On February 14, 1964, JPL released a report noting that an internal command switch could have activated prematurely or that arcing had occurred in the umbilical connector on the payload fairing. However, there was no evidence of the latter happening or any obvious way that it could occur and several modifications were proposed to the camera system and/or the payload fairing.
The NASA review board found that Ranger 6's systems were not as redundant as Jet Propulsion Laboratory had claimed, that prelaunch testing was inadequate, and there had been instances of the cameras turning themselves on at the RCA plant in New Jersey. If the cameras had to be completely redesigned from scratch, the next Ranger mission could be delayed almost a full year.
The full report as submitted to Congress came under criticism from several people at NASA, noting that, although the cameras lacked redundancy, any one of dozens of failure modes in the booster or spacecraft could also result in failure to return any TV images. In regards to the lack of adequate prelaunch testing, they brought up the incident in 1961 with Ranger 1 deploying its solar panels during a ground test and that ground tests with full 60 Watt power had been discontinued on the Block II probes for fear of accidentally igniting the midcourse correction engine on the pad and destroying the entire launch vehicle in the process.
RCA also promised to look into workmanship standards at their main plant in Hightstown, New Jersey, when examination of a sealed Ranger module discovered a plastic bag with screws and washers inside. Although there was suspicion that this had been done by a disgruntled employee, it was far more probable that someone had done it by accident.
Since no obvious reason for the malfunction could be found in the cameras themselves, investigation next shifted to the electrical umbilical on the payload fairing. This umbilical connector would normally be attached on the ground to permit testing of the Ranger's subsystems and only a thin hinged door covered it during launch. One of the pins on the connector was "hot" and could easily be bridged, transferring a voltage to the adjacent pins and activating the TV camera system during launch. As for the cause of it, one possibility was electrostatic discharge, the other was a shock wave of some sort.
Alexander Bratenahl, a physicist at JPL's Space Sciences Division, suggested that the electrical short was caused by venting propellant during Atlas booster section jettison. There was no tracking camera footage of this event on Ranger 6's launch, which had occurred on an overcast day, but film of other Atlas launches showed that a large white plume enveloped the launch vehicle after staging. Convair technicians confirmed that 51 kilograms (112 lb) of LOX was vented from the Atlas after staging, but although the shock wave theory seemed tempting, James Kendall, another Jet Propulsion Laboratory physicist, dismissed it out of hand. The idea of an electrostatic discharge was also unlikely given the thinning air and high altitude of the Atlas when staging occurred.
Bratenahl persisted and studied more film of Atlas launches with the frames enlarged, which revealed light flashes in the post-staging plume. Another phone call to Convair revealed that 30 kilograms (67 lb) of RP-1 were also dumped during staging and that the Atlas's sustainer engine exhaust ignited the propellant cloud, producing these flashes. Since the umbilical door on the payload shroud was only held in place with a thin latching mechanism, hot gases from igniting propellant could have contacted the electrical connector and caused a short. The inadvertent activation of the telemetry system during launch had occurred almost simultaneously with booster jettison at T+140 seconds. With that, the book could be closed on the cause of Ranger 6's failure.
Among the changes made for Ranger 7 included new procedures to apply full power testing to the spacecraft off of the launch pad, where there was no risk of the midcourse correction engine activating on top of a fully fueled Atlas-Agena.
Jet Propulsion Laboratory had originally wanted to have Ranger 7 impact in the same general area as Ranger 6 so the impact crater could be imaged, but lighting conditions during July would not be favorable so they instead decided to go for a little-known area 11° south of the Moon's equator near the Sea of Storms. The probe was shipped to Cape Canaveral in mid-June along with Atlas 250D and Agena 6009.
Rangers 6, 7, 8 and 9 were called Block 3 versions of the Ranger spacecraft. The spacecraft consisted of a hexagonal aluminum frame base 1.5 meters (4 ft 11 in) across on which was mounted the propulsion and power units, topped by a truncated conical tower which held the TV cameras. Two solar panel wings, each 739 millimeters (29.1 in) wide by 1,537 millimeters (60.5 in) long, extended from opposite edges of the base with a full span of 4.6 meters (15 ft), and a pointable high-gain dish antenna was hinge mounted at one of the corners of the base away from the solar panels. A cylindrical quasi-omnidirectional antenna was seated on top of the conical tower. The overall height of the spacecraft was 3.6 meters (12 ft). [4]
Propulsion for the mid-course trajectory correction was provided by a 224-newton (50 lbf) thrust monopropellant hydrazine engine with four jet-vane vector control. Orientation and attitude control about three axes was enabled by twelve nitrogen gas jets coupled to a system of three gyros, four primary Sun sensors, two secondary Sun sensors, and an Earth sensor. Power was supplied by 9,792 silicon solar cells contained in the two solar panels, giving a total array area of 2.3 square meters (25 sq ft) and producing 200 W. Two 1200 watt-hour AgZnO batteries rated at 26.5 V with a capacity for 9 hours of operation provided power to each of the separate communication/TV camera chains. Two 1000 watt-hour AgZnO batteries stored power for spacecraft operations. [4]
Communications were through the quasi-omnidirectional low-gain antenna and the parabolic high-gain antenna. Transmitters aboard the spacecraft included a 60 W TV channel F at 959.52 MHz, a 60 W TV channel P at 960.05 MHz, and a 3 W transponder channel 8 at 960.58 MHz. The telecommunications equipment converted the composite video signal from the camera transmitters into an RF signal for subsequent transmission through the spacecraft high-gain antenna. Sufficient video bandwidth was provided to allow for rapid framing sequences of both narrow- and wide-angle television pictures. [4]
On July 6, Ranger 7 completed its ground testing and was stacked atop the booster. On July 9, a NASA committee met and deemed the booster and spacecraft fully ready for launch, which was targeted for the 27th. [4]
The first countdown on July 27 failed due to a defective battery in the Atlas and a problem with the ground guidance equipment. The next day, all went smoothly and Ranger 7 lifted off from LC-12 at 12:50 PM EST. The weather was clear and cloudless on this launch and Atlas staging was observed by tracking cameras. The expected propellant cloud enveloped the booster, but no anomalous events occurred this time. Thirty minutes after liftoff, the Agena restarted to boost Ranger 7 on a trajectory towards the Moon.
The flight trajectory for Ranger 7 was quite accurate, but a short midcourse correction was carried out early on the morning of July 29 to ensure impact in the Sea of Storms instead of the far side of the Moon. The warmup period for the TV cameras would be performed earlier and made shorter than on Ranger 6. Out of fear of jeopardizing the mission, ground controllers decided that the probe's orientation was acceptable enough and they would not risk maneuvering with the attitude control thrusters to get into a better angle. At 6:09 AM PDT, the first video imagery reached Earth.
As Ranger 7 sped towards the surface of the Moon, TV camera performance remained normal. Images of the cratered lunar surface continued to filter back to JPL headquarters in Pasadena, California, and finally, at 6:25, impact occurred and all signals from the probe ceased. In the JPL control room, there was "rapturous celebration". Ranger 7 had delivered the first close-distance imagery of the lunar surface and "more than anything, even the manned Mercury missions, had at last undone the sting Americans felt at Sputnik 1's launch".
The photographs returned from the probe found that the Moon was most likely "very craggy and rocky with debris everywhere". After speaking to the media, NASA officials were peppered with the obvious question – did the Moon have a surface solid enough that humans could safely land on it? Geologist Gerard Kuiper replied that judging by the images, it seemed likely that at least some of the Moon was smooth enough to land a spacecraft on. However, the actual hardness of the surface couldn't be determined with certainty until a soft landing was made. Nonetheless, Ranger 7's images did seem to suggest that it was solid enough.
Ranger 7 reached the Moon on July 31. The F-channel began its one-minute warm-up 18 minutes before impact. The first image was taken at 13:08:45 UT at an altitude of 2,110 kilometers (1,310 mi). Transmission of 4,308 photographs of excellent quality occurred over the final 17 minutes of flight. The final image taken before impact has a resolution of 0.5 meters (1.6 ft). The spacecraft encountered the lunar surface in direct motion along a hyperbolic trajectory, with an incoming asymptotic direction at an angle of -5.57° from the lunar equator. The orbit plane was inclined 26.84° to the lunar equator. After 68.6 hours of flight, Ranger 7 impacted in an area between Mare Nubium and Oceanus Procellarum (subsequently named Mare Cognitum ) at 10°38′02″S20°40′38″W / 10.6340°S 20.6771°W . [2] (The impact site is listed as 10.63 S, 20.66 W in the initial report "Ranger 7 Photographs of the Moon".) Impact occurred at 13:25:48.82 UT at a velocity of 2.62 km/s (1.63 mi/s). The spacecraft performance was excellent and the success of the mission finally brought a turnaround in NASA's fortunes after the endless string of lunar probe failures since 1958. [4]
Ranger 7 is credited for beginning the "peanut" tradition at NASA command stations. On the success of Ranger 7, someone in the control room was noticed eating peanuts. Since 1964, control rooms ceremonially open a container of peanuts for luck and tradition. [6]
The Mariner program was conducted by the American space agency NASA to explore other planets. Between 1962 and late 1973, NASA's Jet Propulsion Laboratory (JPL) designed and built 10 robotic interplanetary probes named Mariner to explore the inner Solar System – visiting the planets Venus, Mars and Mercury for the first time, and returning to Venus and Mars for additional close observations.
Mariner 6 and Mariner 7 were two uncrewed NASA robotic spacecraft that completed the first dual mission to Mars in 1969 as part of NASA's wider Mariner program. Mariner 6 was launched from Launch Complex 36B at Cape Canaveral Air Force Station and Mariner 7 from Launch Complex 36A. The two craft flew over the equator and south polar regions, analyzing the atmosphere and the surface with remote sensors, and recording and relaying hundreds of pictures. The mission's goals were to study the surface and atmosphere of Mars during close flybys, in order to establish the basis for future investigations, particularly those relevant to the search for extraterrestrial life, and to demonstrate and develop technologies required for future Mars missions. Mariner 6 also had the objective of providing experience and data which would be useful in programming the Mariner 7 encounter five days later.
Mariner 1, built to conduct the first American planetary flyby of Venus, was the first spacecraft of NASA's interplanetary Mariner program. Developed by Jet Propulsion Laboratory, and originally planned to be a purpose-built probe launched summer 1962, Mariner 1's design was changed when the Centaur proved unavailable at that early date. Mariner 1, were then adapted from the lighter Ranger lunar spacecraft. Mariner 1 carried a suite of experiments to determine the temperature of Venus as well to measure magnetic fields and charged particles near the planet and in interplanetary space.
Mariner 3 was one of two identical deep-space probes designed and built by the Jet Propulsion Laboratory (JPL) for NASA's Mariner-Mars 1964 project that were intended to conduct close-up (flyby) scientific observations of the planet Mars and transmit information on interplanetary space and the space surrounding Mars, televised images of the Martian surface and radio occultation data of spacecraft signals as affected by the Martian atmosphere back to Earth.
The Surveyor program was a NASA program that, from June 1966 through January 1968, sent seven robotic spacecraft to the surface of the Moon. Its primary goal was to demonstrate the feasibility of soft landings on the Moon. The Surveyor craft were the first American spacecraft to achieve soft landing on an extraterrestrial body. The missions called for the craft to travel directly to the Moon on an impact trajectory, a journey that lasted 63 to 65 hours, and ended with a deceleration of just over three minutes to a soft landing.
Surveyor 3 is the third lander of the American uncrewed Surveyor program sent to explore the surface of the Moon in 1967 and the second to successfully land. It was the first mission to carry a surface-soil sampling-scoop.
Ranger 3 was a space exploration mission conducted by NASA to study the Moon. The Ranger 3 robotic spacecraft was launched January 26, 1962 as part of the Ranger program. Due to a series of malfunctions, the spacecraft missed the Moon by 22,000 mi (35,000 km) and entered a heliocentric orbit.
Ranger 4 was a spacecraft of the Ranger program, launched in 1962. It was designed to transmit pictures of the lunar surface to Earth stations during a period of 10 minutes of flight prior to crashing upon the Moon, to rough-land a seismometer capsule on the Moon, to collect gamma-ray data in flight, to study radar reflectivity of the lunar surface, and to continue testing of the Ranger program for development of lunar and interplanetary spacecraft.
Ranger 5 was a spacecraft of the Ranger program designed to transmit pictures of the lunar surface to Earth stations during a period of 10 minutes of flight prior to impacting on the Moon, to rough-land a seismometer capsule on the Moon, to collect gamma-ray data in flight, to study radar reflectivity of the lunar surface, and to continue testing of the Ranger program for development of lunar and interplanetary spacecraft. Due to an unknown malfunction, the spacecraft ran out of power and ceased operation. It passed within 725 km of the Moon.
Surveyor 1 was the first lunar soft-lander in the uncrewed Surveyor program of the National Aeronautics and Space Administration. This lunar soft-lander gathered data about the lunar surface that would be needed for the crewed Apollo Moon landings that began in 1969. The successful soft landing of Surveyor 1 on the Ocean of Storms was the first by an American space probe on any extraterrestrial body, occurring on the first attempt and just four months after the first soft Moon landing by the Soviet Union's Luna 9 probe.
The Ranger program was a series of uncrewed space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface of the Moon. The Ranger spacecraft were designed to take images of the lunar surface, transmitting those images to Earth until the spacecraft were destroyed upon impact. A series of mishaps, however, led to the failure of the first six flights. At one point, the program was called "shoot and hope". Congress launched an investigation into "problems of management" at NASA Headquarters and Jet Propulsion Laboratory. After two reorganizations of the agencies, Ranger 7 successfully returned images in July 1964, followed by two more successful missions.
Surveyor 2 was to be the second lunar lander in the uncrewed American Surveyor program to explore the Moon. After launch on September 20, 1966 a mid-course correction failure resulted in the spacecraft losing control. Contact was lost with the spacecraft at 9:35 UTC, September 22.
Ranger 6 was a lunar probe in the NASA Ranger program, a series of robotic spacecraft of the early and mid-1960s to obtain close-up images of the Moon's surface. It was launched on January 30, 1964 and was designed to transmit high-resolution photographs of the lunar terrain during the final minutes of flight until impacting the surface. The spacecraft carried six television vidicon cameras—two wide-angle and four narrow-angle —to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality television pictures. No other experiments were carried on the spacecraft. Due to a failure of the camera system, no images were returned.
Ranger 8 was a lunar probe in the Ranger program, a robotic spacecraft series launched by NASA in the early-to-mid-1960s to obtain the first close-up images of the Moon's surface. These pictures helped select landing sites for Apollo missions and were used for scientific study. During its 1965 mission, Ranger 8 transmitted 7,137 lunar surface photographs before it crashed into the Moon as planned. This was the second successful mission in the Ranger series, following Ranger 7. Ranger 8's design and purpose were very similar to those of Ranger 7. It had six television vidicon cameras: two full-scan and four partial-scan. Its sole purpose was to document the Moon's surface.
Ranger 9 was a Lunar probe, launched in 1965 by NASA. It was designed to achieve a lunar impact trajectory and to transmit high-resolution photographs of the lunar surface during the final minutes of flight up to impact. The spacecraft carried six television vidicon cameras—two wide-angle and four narrow-angle —to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality television pictures. These images were broadcast live on television to millions of viewers across the United States. No other experiments were carried on the spacecraft.
A Moon landing or lunar landing is the arrival of a spacecraft on the surface of the Moon, including both crewed and robotic missions. The first human-made object to touch the Moon was Luna 2 in 1959.
The Lunar Crater Observation and Sensing Satellite (LCROSS) was a robotic spacecraft operated by NASA. The mission was conceived as a low-cost means of determining the nature of hydrogen detected at the polar regions of the Moon. Launched immediately after discovery of lunar water by Chandrayaan-1, the main LCROSS mission objective was to further explore the presence of water in the form of ice in a permanently shadowed crater near a lunar polar region. It was successful in confirming water in the southern lunar crater Cabeus.
The Atlas-Agena was an American expendable launch system derived from the SM-65 Atlas missile. It was a member of the Atlas family of rockets, and was launched 109 times between 1960 and 1978. It was used to launch the first five Mariner uncrewed probes to the planets Venus and Mars, and the Ranger and Lunar Orbiter uncrewed probes to the Moon. The upper stage was also used as an uncrewed orbital target vehicle for the Gemini crewed spacecraft to practice rendezvous and docking. However, the launch vehicle family was originally developed for the Air Force and most of its launches were classified DoD payloads.
The Lunar Atmosphere and Dust Environment Explorer was a NASA lunar exploration and technology demonstration mission. It was launched on a Minotaur V rocket from the Mid-Atlantic Regional Spaceport on September 7, 2013. During its seven-month mission, LADEE orbited the Moon's equator, using its instruments to study the lunar exosphere and dust in the Moon's vicinity. Instruments included a dust detector, neutral mass spectrometer, and ultraviolet-visible spectrometer, as well as a technology demonstration consisting of a laser communications terminal. The mission ended on April 18, 2014, when the spacecraft's controllers intentionally crashed LADEE into the far side of the Moon, which, later, was determined to be near the eastern rim of Sundman V crater.