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Space History for July 26

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P. Gotz discovered asteroid #568 Cheruskia.

Died, Gottlob Frege, German mathematician, logician, philosopher (regarded as a founder of both modern mathematical logic and analytic philosophy)

Born, William McMichael "Bill" Shepherd (at Oak Ridge, Tennessee, USA), Captain USN, NASA astronaut (STS 27, STS 41, STS 52, ISS EO-1)

Astronaut Bill Shepherd, NASA photo

C. A. Wirtanen discovered asteroid #1951 Lick.

Born, William Surles "Bill" McArthur Jr. (at Laurinburg, North Carolina, USA), Colonel US Army, NASA astronaut (STS 58, STS 74, STS 92, ISS 12)

Astronaut Bill McArthur Jr., NASA photo

Died (F-104 crash, flame out after take-off), Iven C. Kincheloe, USAF test pilot (Man-In-Space-Soonest - 1958)

1958 10:07:00 GMT
The US Air Force launched Explorer 4 into orbit from Cape Canaveral, Florida, which mapped project Argus radiation.

Explorer 4, launched 26 July 1958, was a cylindrically shaped satellite instrumented to make the first detailed measurements of charged particles (protons and electrons) trapped in the terrestrial radiation belts. An unexpected tumble motion of the satellite made interpretation of the detector data very difficult. The low power transmitter and the plastic scintillator detector failed 3 September 1958. The two Geiger-Mueller tubes and the cesium iodide crystal detectors continued to operate normally until 19 September 1958. The high power transmitter ceased sending signals on 5 October 1958. It is believed exhaustion of the power batteries caused the failures. The spacecraft decayed from orbit after 454 days on 23 October 1959.

C. Hoffmeister discovered asteroid #2183.

1962 19:22:00 GMT
NASA and the USAF launched X-15A Aero stability and drag test mission # 64 in which Neil Armstrong reached a maximum speed of 6420 kph (Mach 5.74) and a maximum altitude of 30.145 km. A "roller coaster" descent was used to simulate an emergency reentry.

1963 14:38:00 GMT
The Syncom 2 communications satellite was launched, the first spacecraft placed into geostationary orbit.

Syncom 2, launched 26 July 1963, was the first geosynchronous satellite. Although its orbital period was 24 hours, and the spacecraft remained at a nearly constant longitude, the orbit was inclined 33 degrees with respect to the equator, so it was not truly geostationary, but moved in an elongated figure eight pattern that stretched 33 degrees north and south of the equator. Syncom 2 was an experimental communications satellite placed over the Atlantic Ocean and Brazil at 55 degrees W longitude. It began regular service on August 16th, and demonstrated the feasibility of geosynchronous satellite communications. Voice, teletype, facsimile, and data transmission tests were successfully conducted between the Lakehurst, New Jersey ground station and the USNS Kingsport while the ship was at sea off the coast of Africa, and television transmissions were relayed from Lakehurst to the Telstar ground station at Andover, Maine. The Syncoms were forerunners of the Intelsat series of satellites.

Syncom 2 was launched into a high altitude orbit from Cape Canaveral on 26 July 1963. Six hours after launch, the apogee motor was fired to place the spacecraft in an orbit ranging from 34,100 to 36,440 km with a drift rate of 7.5 degrees per day eastward. The apogee was then raised, and the drift rate changed to 4.5 degrees per day westward, toward the desired position over 55 degrees longitude. After two weeks of drifting, the nitrogen jets were pulsed in a series of four firings to slow the spacecraft to near-zero drift on August 16, followed by an alignment maneuver. The final orbit was geosynchronous with an inclination of 33 degrees. Operations were turned over to the Department of Defense on 1 January 1965.

The Syncom satellites were 71 cm diameter x 39 cm high cylinders, with a fully fueled mass of 68 kg. The nozzle of the solid propellant apogee motor, a 1000 lb thrust design used to impart a velocity increase of 1431 meters/sec, extended from the bottom of the cylinder, and a co-axial slotted array communications antenna from the top. Total height, including the nozzle was 64 cm. The radial exterior was covered with 3840 silicon solar cells, providing 29 watts of direct power during the 99 percent of the time the spacecraft was in sunlight. Nickle-cadmium rechargeable batteries provided power when the spacecraft was in the Earth's shadow. No active thermal control was required. Most of the central interior of the spacecraft consisted of the tanks and combustion chamber for the apogee motor, around this were arranged two hydrogen peroxide and two nitrogen tanks, and the electronics. Attitude and velocity control was provided by nitrogen jets to align the spin axis, and hydrogen peroxide jets to position the satellite. Each system had two jets, one parallel and one perpendicular to the spin axis.

Syncom employed a redundant, frequency-translation, active repeater communication system designed to handle one two-way telephone or 16 one-way teletype channels. The dual transponders utilized 2-watt traveling wave tubes. Receiver and transmitter selection was made by ground command. One receiver had a 13 MHz bandwidth for TV transmission, the other a 5 MHz bandwidth. The receiving gain was 2 dB through the slotted dipole antenna. Signals were received on two frequencies near 7360 MHz and retransmitted on 1815 MHz. The slotted dipole transmitting antenna radiated a pancake-shaped beam 25 degrees wide with its plane perpendicular to the spacecraft spin axis. There were also four whip antennas oriented normal to the spin axis for telemetry and command.

Syncom 2, the first geosynchronous satellite, NASA photo

1969 02:06:00 GMT
Intelsat 3 F-5 was launched from Cape Canaveral, Florida, but a third stage failure left the communications satellite in an unusable orbit.

N. Chernykh discovered asteroid #1836 Komarov.

1971 13:34:00 GMT
NASA launched Apollo 15 (SA-510, CSM "Endeavour" and LEM "Falcon"), the fourth mission to land astronauts on the Moon's surface.

Apollo 15 was the fourth mission in which humans walked on the Lunar surface and returned to Earth: On 30 July 1971, Apollo 15 Commander David R. Scott and LM pilot James B. Irwin landed in the Hadley Rille/Apennines region of the Moon in the Lunar Module (LM) while the Command and Service Module (CSM), with CM pilot Alfred M. Worden, continued in Lunar orbit. During their stay on the Moon, the astronauts set up scientific experiments, took photographs, and collected Lunar samples. The LM took off from the Moon on 2 August, and the astronauts returned to Earth on 7 August.

Apollo 15 was launched on 26 July 1971 on Saturn V SA-510 from Pad 39A at the Kennedy Space Center, Florida. The spacecraft was inserted into Earth orbit 11 minutes 44 seconds after liftoff, at 13:45:44 UT, and translunar injection took place at 16:30:03 UT. The CSM separated from the S-IVB stage at 16:56:24 UT, and docked with the LM at 17:07:49 UT, televised using an onboard color camera.

The S-IVB stage was released and sent into a Lunar impact trajectory, impact occurring on 29 July at 20:58:42.9 UT at 1.51 S, 11.81 W with a velocity of 2.58 km/s at a 62 degree angle from the horizontal, 188 kilometers northeast of the Apollo 14 landing site and 355 kilometers northeast of the Apollo 12 site. The impact was detected by both the Apollo 12 and Apollo 14 seismometers, left on the moon in November 1969 and February 1971.

A short was discovered in the service propulsion system, and contingency procedures were developed for using the engine. A mid-course correction was performed on 27 July at 18:14:22 UT and another on 29 July at 15:05:15. During the translunar cruise, it was discovered that the LM range/range-rate exterior glass cover had broken and a small water leak had developed in the CM requiring repair and clean up, in part to avoid breathing in the glass shards. The Scientific Instrument Module (SIM) door was jettisoned at 15:40 UT on 29 July, and Lunar orbit insertion took place at 20:05:47 UT. The descent orbit maneuver was executed at 00:13:49 UT on 30 July.

Scott and Irwin entered the LM and the LM-CSM undocking maneuver was initiated at 17:48 UT, but undocking did not take place. Worden found a loose umbilical plug and reconnected it, allowing the LM to separate from the CSM at 18:13:30 UT. The LM fired its descent engine at 22:04:09 UT and landed at 22:16:29 UT on 30 July 1971 in the Mare Imbrium region at the foot of the Apennine mountain range at 26.1 N, 3.6 E, 600 meters north-northwest of the proposed target. The CSM remained in a slightly elliptical orbit from which Worden performed scientific experiments.

About two hours after landing, following cabin depressurization, Scott performed a 33 minute 7 second standup EVA in the upper hatch of the LM, during which he described and photographed the landing site.

The first crew EVA on the Lunar surface began at 13:04 UT 31 July. The crew collected and stowed a contingency sample, unpacked the ALSEP and other experiments, and prepared the Lunar Roving Vehicle (LRV) for operations. Some problems were encountered in the deployment and checkout of the LRV, used for the first time, but they were quickly resolved. The first EVA traverse was to the Apennine mountain front, after which the ALSEP was deployed and activated, and one probe of a Heat Flow experiment was emplaced. A second probe was not emplaced until EVA-2 because of drilling difficulties. The first EVA lasted 6 hours 32 minutes 42 seconds.

The second EVA began at 11:49 UT 1 August. The astronauts made a maintenance check on the LRV, then began the second planned traverse of the mission. On completion of the traverse, Scott and Irwin completed the placement of heat flow experiment probes, collected a core sample, and deployed the American flag. They then stowed the sample container and the film in the LM, completing a second EVA of 7 hours 12 minutes 14 seconds.

The third EVA began at 8:52 UT 2 August, included another traverse, and ended 4 hours 49 minutes 50 seconds later. After the final EVA, Scott performed a televised demonstration of a hammer and feather falling at the same rate in the Lunar vacuum.

The total Apollo 15 Lunar surface EVA time was 18 hours 34 minutes 46 seconds. During the three moonwalks, Scott and Irwin covered 27.9 km, collected 76.8 kg (170 pounds) of rock and soil samples, took photographs, and set up the ALSEP and performed other scientific experiments. This was the first mission to employ the LRV, used to explore regions within 5 km of the LM landing site.

While the Lunar Module was on the Moon, Worden completed 34 Lunar orbits in the CSM, operating SIM experiments and cameras to obtain data concerning the Lunar surface and environment. The SIM equipment included a panoramic camera, gamma ray spectrometer, mapping camera, laser altimeter, and a mass spectrometer. X-ray spectrometer data indicated a richer abundance of aluminum in the highlands, especially on the far side, but greater concentrations of magnesium in the maria.

The LM ascent stage lifted off from the Moon at 17:11:22 UT on 2 August, televised for the first time, after 66 hours, 55 minutes on the Lunar surface. After the LM docked with the CSM at 19:09:47 UT, the Lunar samples, film, and other equipment were transferred from the LM to the CSM. The LM was jettisoned at 01:04:14 UT on 3 August, after a one orbit delay to ensure LM and CSM hatches were completely sealed. The LM impacted the Moon on 3 August 03:03:37.0 UT at 26.36 N, 0.25 E, 93 km west of the Apollo 15 ALSEP site, with an estimated impact velocity of 1.7 km/s at an angle of ~3.2 degrees from horizontal. Its impact was recorded by the Apollo 12, Apollo 14, and Apollo 15 seismometers, left on the Moon during each of those missions.

Experiments were performed from orbit over the next day. After Apollo 15 executed an orbit-shaping maneuver, the scientific subsatellite was spring-launched from the SM SIM bay at 20:13:19 UT on 4 August into a 102.0 x 141.3 km Lunar orbit. The satellite measured interplanetary and Earth magnetic fields near the Moon, and carried charged-particle sensors and equipment to detect variations in Lunar gravity caused by mascons (mass concentrations).

Transearth injection began on the next orbit with a 2 minute, 21 second main engine burn at 21:22:45 UT. On 5 August, Worden carried out the first deep space EVA when he exited the CM and made three trips to the SIM bay at the rear of the SM to retrieve film cannisters and check the equipment. Total EVA time was 38 minutes, 12 seconds.

The CM separated from the SM at 20:18:00 UT on 7 August. During descent, one of the three main parachutes failed to open fully, resulting in a descent velocity of 35 km/hr (21.8 mph), 4.5 km/hr (2.8 mph) faster than planned, causing a hard but safe landing. Apollo 15 splashed down in the Pacific Ocean on 7 August 1971 at 20:45:53 UT (4:45:53 PM EDT) after a mission elapsed time of 295 hours, 11 minutes, 53 seconds (12 days 7 hours 12 minutes). The splashdown point was 26 deg 7 min N, 158 deg, 8 min W, 330 miles north of Honolulu, Hawaii and 9.8 km (6.1 mi) from the recovery ship USS Okinawa. The astronauts were carried to the ship by helicopter, and the CM was retrieved and placed on board.

Performance of the spacecraft, the first of the Apollo J-series missions (long duration stays on the Moon with a greater focus on science than on previous flights), was excellent for most aspects of the mission. The primary mission goals of exploration of the Hadley-Appenine region, deployment of the ALSEP and other scientific experiments, collection of Lunar samples, surface photography, and photography and other scientific experiments from orbit, and engineering evaluation of new Apollo equipment, particularly the rover, were achieved. Scott, 39, was an Air Force Colonel on his third spaceflight (he'd flown previously on Gemini 8 and Apollo 9), Worden, 39, was an Air Force Major on his first spaceflight, and Irwin, 41, was an Air Force Lt. Colonel also on his first spaceflight.

The Apollo 15 command module "Endeavor" is on display at the USAF Museum at Wright-Patterson Air Force Base, Dayton, Ohio.

See also the pages for the Apollo 15 Lunar Module /ALSEP and the Apollo 15 SIVB

The Apollo program included a large number of uncrewed test missions and 12 crewed missions: three Earth orbiting missions (Apollo 7, 9 and Apollo-Soyuz), two Lunar orbiting missions (Apollo 8 and 10), a Lunar swingby (Apollo 13), and six Moon landing missions (Apollo 11, 12, 14, 15, 16, and 17). Two astronauts from each of the six missions walked on the Moon (Neil Armstrong, Edwin Aldrin, Charles Conrad, Alan Bean, Alan Shepard, Edgar Mitchell, David Scott, James Irwin, John Young, Charles Duke, Gene Cernan, and Harrison Schmitt), the only humans to date (2014) to have set foot on another solar system body.

NASA photo, Apollo 15 builds thrust and swing arms begin to retract. 26 July 1971

1975 14:18:00 GMT
USSR Soyuz 18 landed after cosmonauts Kilmuk and Sevastyanov has spent a record 63 days in orbit at the Salyut 4 space station.

Soyuz 18 was a manned Soviet mission launched 24 May 1975 from the Baikonur Cosmodrome. The flight crew consisted of Cosmonauts Kilmuk and Sevastyanov. Soyuz 18 docked with the Salyut 4 space station for joint experiments with the Salyut scientific orbital station. The crew remained aloft aboard the station during the Apollo-Soyuz Test Project joint flight, and set Soviet record for time in space. Soyuz 18 was recovered on 26 July 1975 after 63 days in space when it landed 56 km east of Arkalyk.

E. Bowell discovered asteroids #2845 Franklinken and #2882 Tedesco.

Light flashes were seen on Jupiter's moon Io.

1988 05:01:00 GMT
USSR launched the Meteor 3-2 weather satellite from Plesetsk for continued improvement of the meteorological system, including testing of information gathering and measuring apparatus, and of remote sensing methods.

During the 3h 31m EVA Mir EO-6-2, cosmonauts Solovyev and Balandin dismantled equipment and temporarily closed a damaged hatch on the Mir space station.

Seeking to keep the Glonass network operating, Russia invited China to participate in financing its satellites. An operational system requires 24 satellites, by mid-2000 only 14 were available, 8 fully operating. 1.5 billion rubles a year was needed.

2000 00:45:00 GMT
Russia's Zvezda living module docked with the Russian/US Zarya/Unity stack, forming the basic core of the International Space Station.

Years behind schedule, the Russian financed and built Zvezda living module of the International Space Station finally reached orbit when it was launched 12 July 2000. Zvezda's initial orbit was 179 x 332 km x 51.6 deg. On 14 July, the orbit was raised to 288 x 357 km, the ISS was then in a 365 x 372 km orbit. After matching orbits with the ISS, Zvezda became the passive docking target for the Russian built, US financed Zarya module already attached to the station. The Zarya/Unity stack docked with the Zvezda module at 00:45 GMT on July 26, forming the basic core of the International Space Station.

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