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Race To Space
Someone will win the prize...
               ... but at what cost?
Visit RaceToSpaceProject.com to find out more!

Died, John Napier, Scottish mathematician, inventor (logarithms)
ref: en.wikipedia.org

Died, Joseph Jerome Lefrancais de Lalande, French astronomer
ref: en.wikipedia.org

Born, Benjamin Pierce, US mathematician, astronomer
ref: en.wikipedia.org

Born, Zenobe-Theophile Gramme, Belgian inventor (electric motor)
ref: en.wikipedia.org

R. Luther discovered asteroid #53 Kalypso (goddess of silence).

Died, Heinrich Wilhelm Dove, Prussian physicist, meteorologist (climate, electricity, binaural beats)
ref: en.wikipedia.org

Born, Mikhail Vasilyevich Khrunichev, Russian Minister of Aviation Industries 1946-1953
ref: en.wikipedia.org

Died, Sir William Crookes, English chemist and physicist (spectroscopy, vacuum tubes, Crookes radiometer)
ref: en.wikipedia.org

K. Reinmuth discovered asteroid #1716 Peter.

Born, Vladimir T. Isakov (at Zilair, Bashkir ASSR), Soviet cosmonaut candidate, later Chief CapCom for Mir flights
ref: www.spacefacts.de

L. Oterma discovered asteroid #2332 Kalm.

The Convention on International Civil Aviation went into effect.
ref: www.icao.int

Goethe Link Observatory discovered asteroid #1798 Watts, #2641 Lipschutz and #3070.

Concrete pouring reportedly began for the first launch pad at the Soviet Baikonur cosmodrome.
ref: www.russianspaceweb.com

1968 12:00:01 GMT
NASA launched Saturn/Apollo 6 (AS-502) as the final qualification of the Saturn V launch vehicle and Apollo spacecraft for manned Apollo missions.
Apollo  6 lifting off from Cape Canaveral, Florida, NASA photo Source: NSSDCA Master Catalog apollo6_launch.jpg
Apollo 6 lifting off from Cape Canaveral, Florida, NASA photo
Source: NSSDCA Master Catalog

The unmanned Saturn/Apollo 6 mission, launched 4 April 1968, was designed as the final qualification of the Saturn V launch vehicle and Apollo spacecraft for manned Apollo missions. The spacecraft consisted of the three stage Saturn V, the Apollo Command and Service Module (CSM) and a boilerplate Lunar Module (LM). The primary objectives of the mission were to demonstrate structural and thermal integrity and compatibility of the launch vehicle and spacecraft, confirm launch loads and dynamic characteristics, and verify stage separations, propulsion, guidance and control, electrical systems, emergency detection system, and mission support facilities and operations, including Command Module recovery.

Three major problems occurred during the mission. Two minutes and five seconds after launch, the Saturn V structure underwent a severe pogo oscillation, without damage to the spacecraft structure. Due to a manufacturing flaw and unrelated to the pogo oscillations, structural panels were lost from the Lunar Module adapter. Finally, after the completion of first stage firing and part way through the second stage burn, two of the five second stage J-2 engines shut down prematurely. The planned 175 km circular Earth orbit was not achieved, instead, after completion of the third stage burn, the spacecraft was in a 172.1 x 223.1 km, 89.8 min orbit. After two orbits, the third stage failed to reignite as planned, so the Service Module propulsion system was used to boost the spacecraft to an apogee of 22,225.4 km, from which the planned Lunar reentry simulation took place at 36,025 km/hr, slightly less than the planned velocity of 40,000 km/hr. The Command Module splashed down 80 km off target 9 hours 50 minutes after launch and was recovered in good condition.
ref: nssdc.gsfc.nasa.gov

1973 09:00:00 GMT
The USSR launched Salyut 2, intended to be a space station for experiments and observations, however, a thruster malfunction rendered it unusable.

The Salyut 2 space station, launched 4 April 1973, was designed for scientific research and testing of onboard systems and units. Salyut 2 was intended for service as a space station for experiments and observations. On 11 April 1973, a suspected thruster problem caused craft to tumble out of control, resulting in four solar panels being torn loose from the space station, and cutting off all power to the space station. The craft reentered the Earth's atmosphere 28 May 1973.
ref: nssdc.gsfc.nasa.gov

N. Chernykh discovered asteroid #2369 Chekhov.

CERN achieved the first proton-antiproton beam collision (570 GeV).
ref: timeline.web.cern.ch

1983 13:30:00 EST (GMT -5:00:00)
NASA launched STS 6 (Challenger 1, 6th Shuttle mission) to carry the Tracking and Data Relay Satellite-1 (TDRS-1) to orbit. The first Shuttle space walk occurred during this flight.

Challenger's first launch was originally set for 20 January 1983, but was postponed due to a hydrogen leak into the number one main engine aft compartment discovered during a 20 second Flight Readiness Firing (FRF) on 18 December 1982. Cracks in the number one main engine were confirmed to be the cause of the leak during the second FRF performed 25 January 1983. All three main engines were removed while the Shuttle was on the pad and the fuel line cracks were repaired. Main engines two and three were reinstalled following extensive failure analysis and testing, while the number one main engine was replaced. An additional delay was caused by contamination to the Tracking and Data Relay Satellite-1 (TDRS-1) during a severe storm. The launch of STS 6 on 4 April 1983 then proceeded as scheduled.

The primary payload for STS 6 was the first Tracking and Data Relay Satellite (TDRS-1). A malfunction of the Inertial Upper Stage booster resulted in placement of the spacecraft into an improper but stable orbit. Additional propellant aboard the satellite was used over the next several months to gradually place TDRS-1 into its properly circularized orbit.

The first space walk of the Shuttle program was performed on 7 April 1983 by Peterson and Musgrave, lasting about four hours, 17 minutes.

Other payloads on STS 6 were: Continuous Flow Electrophoresis System (CFES), Monodisperse Latex Reactor (MLR), Radiation Monitoring Experiment (RME), Night/Day Optical Survey of Lightning (NOSL), and three Get Away Special (GAS) canisters. This mission used the first lightweight external tank and lightweight solid rocket booster casings.

STS 6 ended on 9 April 1983 when Challenger landed on revolution 81 on Runway 22, Edwards Air Force Base, California. Rollout distance: 7,244 feet. Rollout time: 49 seconds. Orbit altitude: 184 nautical miles. Orbit inclination: 28.5 degrees. Mission duration: five days, zero hours, 23 minutes, 42 seconds. Miles Traveled: 2.1 million. The orbiter was returned to Kennedy Space Center 16 April 1983.

The flight crew for STS 6 was: Paul J. Weitz, Commander; Karol J. Bobko, Pilot; Donald H. Peterson, Mission Specialist; F. Story Musgrave, Mission Specialist.
ref: www.nasa.gov

1997 14:20:32 EST (GMT -5:00:00)
NASA launched STS 83 (Columbia 22, 83rd Shuttle mission) carrying the Microgravity Science Laboratory-1 (MSL-1) experiment package to orbit.

STS 83's launch was originally set for 3 April 1997, but was delayed 24 hours on 1 April due to a requirement to add additional thermal insulation to a water coolant line in the orbiter's payload bay. Managers determined that the line, which cools various electronic systems on the orbiter, was not properly insulated and could possibly freeze on-orbit. Liftoff on 4 April 1997 was then delayed an additional 20 minutes, 32 seconds due to an orbiter access hatch seal which had to be replaced.

The first flight of the Microgravity Science Laboratory (MSL-1), the primary payload of STS 83, was cut short due to concerns about one of Columbia's three fuel cells, marking only the third time in the Shuttle program history that a mission ended early. (STS-2, 1981 and STS-44, 1991 were the other two times). Fuel cell number 2 had shown some erratic readings during prelaunch startup, but was cleared to fly after additional checkout and test procedures. Shortly after on-orbit operations began, the number 3 fuel cell substack differential voltage began trending upward. There are three fuel cells on each orbiter, each containing three substacks made up of two banks of 16 cells. In one substack of fuel cell number 2, the difference in output voltage between the two banks of cells was increasing. The fuel cells use a reaction of liquid hydrogen and liquid oxygen to generate electricity and produce drinking water. Although one fuel cell produces enough electricity to conduct on-orbit and landing operations, Shuttle flight rules require all three to be functioning properly to ensure crew safety and provide sufficient backup capability during reentry and landing.

When a purge failed to halt the upward trend, the fuel cell was shut down. Additional purges and other measures failed to correct the anomaly, and around 10 a.m. on 6 April, the Mission Management Team ordered the mission to end early. Fuel cell number 2 was shut down for the remainder of the mission later that afternoon and safed.

The crew was able to conduct some science in the MSL-1 Spacelab module despite the early return. Work was performed in the German electromagnetic levitation furnace facility (TEMPUS) on an experiment called Thermophysical Properties of Undercooled Metallic Melts. This experiment studied the amount of undercooling that can be achieved before solidification occurs. Another experiment performed was the Liquid-Phase Sintering II experiment in the Large Isothermal Furnace. This investigation used heat and pressure to test theories about how the liquefied component bonds with the solid particles of a mixture without reaching the melting point of the new alloy combination.

Also conducted were two fire-related experiments. The Laminar Soot Processes experiment allowed scientists to observe for the first time the concentration and structure of soot from a fire burning in microgravity. The Structure of Flame Balls at Low Lewis-number experiment completed two runs. This experiment was designed to determine under what conditions a stable flame ball can exist, and if heat loss is responsible in some way for the stablilization of the flame ball during burning.

A decision to refly the MSL-1 mission in its entirety was made by the Mission Management Team in the days following Columbia's return. The reflight was first designated STS 83R and then renamed STS 94.

STS 83 ended on 8 April 1997 when Columbia landed on revolution 64 on Runway 33, Kennedy Space Center, Florida, on the first KSC opportunity for the day. Rollout distance: 8,602 feet (2,622 meters). Rollout time: 59 seconds. Orbit altitude: 184 statute miles. Orbit inclination: 28.45 degrees. Mission duration: three days, 23 hours, 12 minutes, 39 seconds. Miles Traveled: 1.5 million.

The flight crew for STS 83 was: James D. Halsell, Mission Commander; Susan L. Still, Pilot; Janice E. Voss, Payload Commander; Donald A. Thomas, Mission Specialist; Michael L. Gernhardt, Mission Specialist; Roger Crouch, Payload Specialist; Greg Linteris, Payload Specialist.
ref: www.nasa.gov

1997 16:47:00 GMT
DMSP 5D-2/F14 (Defense Meteorological Satellite Program) was launched from Vandenberg AFB, California, on a Titan 2.
ref: nssdc.gsfc.nasa.gov

NASA's MESSENGER probe started science operations in Mercury orbit.

The Mercury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) mission was designed to study the characteristics and environment of Mercury from orbit. Specifically, the scientific objectives of the mission were to characterize the chemical composition of Mercury's surface, the geologic history, the nature of the magnetic field, the size and state of the core, the volatile inventory at the poles, and the nature of Mercury's exosphere and magnetosphere over a nominal orbital mission of one Earth year.

MESSENGER launched into a parking orbit on 3 August 2004 on a Delta 7925H (a Delta II Heavy launch vehicle with nine strap-on solid-rocket boosters). The Delta booster second stage's second burn raised the orbit, then the PAM-D solid motor burned to put the probe on an escape trajectory into a 0.92 x 1.08 AU x 6.4 deg heliocentric orbit. The spacecraft was injected into solar orbit 57 minutes after launch. The solar panels were then deployed and the spacecraft began sending data on its status.

One year after launch, on 2 August 2005, MESSENGER flew by Earth at an altitude of 2347 km. On 12 December 2005 at 11:30 UT, MESSENGER fired its large thruster for 524 seconds, changing the spacecraft velocity by 316 m/s and putting it on course for its 24 October 2006 Venus flyby at an altitude of 2990 km. The second Venus flyby took place on 5 June 2007 at 23:08 UT (7:08 p.m. EDT) at an altitude of approximately 337 km. The first of three Mercury flybys, all at roughly 200 km altitude, occurred on 14 January 2008 at 19:04 :39 UT, and the second on 6 October 2008 at 08:40:22 UT. The third took place on 29 September 2009 at 21:54:58 UT at a distance of 228 km. There were also five deep space manuevers. Data collected during the Mercury flybys was used to help plan the scientific campaign during the orbital phase.

Mercury orbit insertion took place with a 15 minute burn starting at 00:45 UT on 18 March 2011 (8:45 p.m. 17 March EDT) requiring a delta-V of 0.862 km/s from the Aerojet 660N engine. Science observations began on April 4 at 20:40 UT (4:40 p.m. EDT). The nominal orbit had a periapsis of 200 km at 60 degrees N latitude, an apoapsis of 15,193 km, a period of 12 hours and an inclination of 80 degrees. The periapsis slowly rose due to solar perturbations to over 400 km at the end of 88 days (one Mercury year) at which point it was readjusted to a 200 km, 12 hour orbit via a two burn sequence.

Data was collected from orbit for one Earth year, the end of the primary mission was in March 2012. Extensions to the mission allowed the spacecraft to operate for an additional 3 years until the propellant necessary to maintain its orbit was exhausted. The MESSENGER spacecraft impacted the surface of Mercury as planned on 30 April 2015 at 19:26 UT (3:26 p.m. EDT).

Global stereo image coverage at 250 m/pixel resolution was completed. The mission has also yielded global composition maps, a 3-D model of Mercury's magnetosphere, topographic profiles of the northern hemisphere, gravity field, altitude profiles of elemental species, and a characterization of the volatiles in permanently shadowed craters at the poles.

The MESSENGER spacecraft was a squat box (1.27 m x 1.42 m x 1.85 m) with a semi-cylindrical thermal shade (roughly 2.5 meters tall and 2 meters wide) for protection from the Sun and two solar panel wings extending radially about 6 meters from tip to tip. A 3.6 meter magnetometer boom also extended from the craft. The total mass of the spacecraft was 1093 kg, 607.8 kg of which was propellant and helium. The structure was primarily graphite-cyanate-ester (GrCE) composite and consisted of two vertical panels which supported two large fuel tanks, and two vertical panels which supported the oxidizer tank and plumbing panel. The four vertical panels made up the center column and were bolted at their aft ends to an aluminum adapter. A single top deck panel mounted the LVA (large velocity adjust) thruster, small thrusters, helium and auxiliary fuel tanks, star trackers and battery.

Main propulsion was via the 645-N, 317-s bipropellant LVA thruster, four 22-N monopropellant thrusters providing spacecraft steering during main thruster burns, and ten 4-N monopropellant thrusters used for attitude control. There was also a reaction-wheel attitude control system. Knowledge for attitude control was provided by star tracking cameras, an inertial measurement unit, and six solar sensors. Power was provided by the solar panels, which extended beyond the sunshade and were rotatable to balance panel temperature and power generation, and provided a nominal 450 W in Mercury orbit. The panels were 70% optical solar reflectors and 30% GaAs/Ge cells. The power was stored in a common-pressure-vessel nickel-hydrogen battery, with 11 vessels and 2 cells per vessel.

Communications were in the X-band, with downlink through two fixed phased-array antenna clusters, and uplink and downlink through medium- and low-gain antennas on the forward and aft sides of the spacecraft. Passive thermal control, primarily a fixed opaque ceramic cloth sunshade, was utilized to maintain operating temperatures near the Sun. Radiators were built into the structure and the orbit was optimized to minimize infrared and visible light heating of the spacecraft from the surface of Mercury. Multilayer insulation, low conductivity couplings, and heaters were also used to maintain temperatures within operating limits.

Five science instruments were mounted externally on the bottom deck of the main body: the Mercury Dual Imaging System (MDIS), Gamma-Ray and Neutron Spectrometer (GRNS), X-ray Spectrometer (XRS), Mercury Laser Altimeter (MLA), and Atmospheric and Surface Composition Spectrometer (MASCS). The Energetic Particle and Plasma Spectrometer (EPPS) was mounted on the side and top deck and the magnetometer (MAG) was at the end of the 3.6 m boom. Radio Science (RS) experiments used the existing communications system.

The highly successful orbital mission came to an end after more than four years in orbit around Mercury, as the spacecraft ran out of propellant and the force of solar gravity caused it to impact the surface of Mercury at 3:26 p.m. EDT on 30 April 2015.

More information about the spacecraft and its research results can be found on the MESSENGER Web site at John Hopkins University's Applied Physics Laboratory.
ref: nssdc.gsfc.nasa.gov

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