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 . Space History News - People and events in development of space travel Space History News - People and events in development of space travel Space History News - People and events in development of space travel  

Space History for July 4

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A supernova was observed by the Chinese and Amerindians as a star exploded in the constellation Taurus. The explosion remained bright enough to be seen during daylight for several months, the remains are now visible as the Crab Nebula.

Hubble mosaic of the Crab Nebula

Born, Jean-Pierre Blanchard, aviation pioneer (first balloon flights in England and US)

William Herschel made his last recorded telescopic observation, of the 1819 comet.

Born, Henrietta Leavitt, American astronomer, discovered the cepheid period-luminosity relation

Born, Rube Goldberg, made the easy outrageously difficult, the only person ever to be listed in the Merriam Webster Dictionary as an adjective

A. Borrelly discovered asteroid #369 Aeria.

Died, Giovanni Schiaparelli, Italian astronomer (Martian canali, Italian for "channels" (not "canals"), associated the Perseid and Leonid meteor showers with comets)

M. Wolf discovered asteroid #914 Palisana.

Died, Madame Marie Sklodowska Curie, discovered radium (Nobel Physics 1903, Chemistry 1911)

Marie Curie (nee Sklodowska) (7 November 1867 - 4 July 1934) was born in Warsaw, Poland, to a family of teachers who believed strongly in education. She moved to Paris to continue her studies and there met Pierre Curie, who became both her husband and colleague in the field of radioactivity. The couple later shared the 1903 Nobel Prize in Physics with Henri Becquerel "in recognition of the extraordinary services they have rendered by their joint researches on the radiation phenomena discovered by Professor Henri Becquerel." Marie was widowed in 1906, but continued the couple's work and went on to become the first person ever to be awarded two Nobel Prizes, recipient of the 1911 Nobel Prize in Chemistry "in recognition of her services to the advancement of chemistry by the discovery of the elements radium and polonium, by the isolation of radium and the study of the nature and compounds of this remarkable element." During World War I, Curie organized mobile X-ray teams.

See also:
* Facts re. Marie Curie, Nobel Prize in Physics 1903
* Marie Curie's 1911 Nobel Prize biography
* Facts re. Marie Curie, Nobel Prize in Chemistry 1911

The first research rocket was launched from NASA's Wallops Island Station. The Tiamat missile was a two stage rocket which employed six booster rockets, had automatic stabilization, and pre-programmed maneuvers.

Tiamat being prepared for launch from Wallops Island, NASA photo

Dr. William Shockley announced the invention of the junction transistor at Bell Labs, Murray Hill, New Jersey.

1968 17:31:00 GMT
NASA launched Explorer 38 (RAE 1, Radio Astronomy Explorer) from Cape Canaveral, Florida, to gather Earth, solar, and cosmic radio emission data.

The RAE-1 spacecraft, launched 4 July 1968, measured the intensity of celestial radio sources, particularly the Sun, as a function of time, direction, and frequency (0.2 to 20 MHz). The spacecraft was gravity gradient oriented, weighed 193 kg, and had an average power consumption of 25 W. It carried two 750-ft-long V-antennas, one facing toward the Earth and one facing away. A 120-ft-long dipole antenna was oriented tangentially with respect to the Earth's surface. The spacecraft was also equipped with one 136-MHz telemetry turnstile. Onboard experiments consisted of four step-frequency Ryle-Vonberg radiometers operating from 0.45 to 9.18 MHz, two multichannel total power radiometers operating from 0.2 to 5.4 MHz, one step frequency V-antenna impedance probe operating from 0.24 to 7.86 MHz, and one dipole antenna capacitance probe operating from 0.25 to 2.2 MHz. RAE-1 was designed for a one year minimum operating lifetime, but the spacecraft tape recorder performance began to deteriorate after 2 months in orbit. In spite of several cases of instrument malfunction, good data were obtained on all three antenna systems.

USSR Soyuz 14 docked with the Salyut 3 space station.

Soyuz 14 was launched 3 July 1974 as a test of Salyut's engineering systems and energy supply. On 4 July, Soyuz 14 docked with the Salyut 3 space station after 15 revolutions of the Earth. The planned experimental program included manned military reconnaissance of the Earth's surface, assessing the fundamental value of such observations, and some supplemental medico-biological research. Soyuz 14 landed on 19 July 1974 following 15 days, 17 hours docked at Salyut 3. After the crew's return to Earth, research continued in development of the on-board systems and the principles of remote control of such a station.

L. Chernykh discovered asteroid #3332.

1978 13:29:00 GMT
USSR Soyuz 30 touched down in Soviet Kazakhstan, returning from Salyut 6 (Salyut 6 EP-3, Salyut 6 EO-2).

1982 09:09:31 PDT (GMT -7:00:00)
NASA's STS 4 (Columbia 4, 4th Shuttle mission) ended, completing the Department of Defense flight which also flew the Continuous Flow Electrophoresis System (CFES) experiment.

The STS 4 launch on 27 June 1982 proceeded as scheduled with no delays. The two solid rocket booster casings were lost when their main parachutes failed and they impacted the Atlantic Ocean's water and sank. Some rainwater penetrated the protective coating of several tiles while the orbiter was on the pad. On orbit, the affected area was turned toward the Sun, which vaporized the water and prevented further tile damage from freezing water.

STS 4 was the final Space Transportation System research and development (R&D) flight. In addition to a classified Department of Defense payload, the cargo included the first Get Away Specials, which contained nine experiments from Utah State University; the first commercial experiment involving the Continuous Flow Electrophoresis System (CFES); the Monodisperse Latex Reactor (MLR); the Induced Environment Contamination Monitor (IECM), which was deployed, and two Shuttle Student Involvement Program (SSIP) experiments. The crew took data for two medical experiments on themselves, operated the remote manipulator arm to swing IECM around the orbiter, and took photos of lightning activity in the Earth's atmosphere.

STS 4 ended when Columbia landed on revolution 113 on Runway 22, Edwards Air Force Base, California, the first landing on the 15,000 foot long concrete runway. Rollout distance: 9,878 feet. Rollout time: 73 seconds. Launch weight: 241,664 pounds. Orbit altitude: 197 nautical miles. Orbit inclination: 28.5 degrees. Mission duration: seven days, one hour, nine minutes, 31 seconds. Miles Traveled: 2.9 million. The orbiter was returned to Kennedy Space Center on 15 July 1982.

The flight crew for STS 4 was: Thomas K. Mattingly, Commander; Henry W. Hartsfield Jr., Pilot.

USSR launched BOR-5 Flight 1 from Kapustin Yar, a suborbital test of a 1/8 scale model of the Buran spaceplane, with a typical trajectory of ascent to 120 km, from which it was pitched down to drive the model into the atmosphere at 45 degree at Mach 18.5.

Died, Bengt Stromgren, astrophysicist (stellar structure, H II regions, Bruce Medal 1959)

Bengt Georg Daniel Stromgren (21 January 1908 - 4 July 1987) was a Danish astronomer and astrophysicist who did important research in stellar structure in the 1930s but is best known for his work on ionized gas clouds - H II regions - around hot stars. He surveyed H II regions and found relations between the gas density, the luminosity of the star, and the size of the Stromgren sphere of ionized hydrogen around it.

See also

Per Lindstrand and Richard Branson became the first travelers to successfully cross the Atlantic Ocean in a hot-air balloon.

Richard Branson and Per Lindstrand lifted off Thursday morning 3 July 1987 from a ski resort at Carrabassett Valley, Maine in the Virgin Atlantic Flyer, a hot air balloon approximately 21 stories tall. They covered the first 1,000 miles of their 3,400-mile journey in a little more than 10 hours, traveling far faster than expected with the aid of the jet stream. They broke the distance mark for hot-air balloons at 907 miles while passing about 140 miles southeast of St. John's, Newfoundland on the afternoon of 3 July.

Their balloon got into trouble soon after it crossed the Irish coast. Low clouds forced the pair to bring the balloon down and seek a landing spot even though they believed the wind would have carried them to their goal, the Mull of Kintyre, a peninsula on the Scottish coast. After descending from 27,000 feet, they hit the ground near Limavady in Northern Ireland, scraping along the ground and losing two fuel tanks.

Regaining altitude, the billowing black and silver craft proceeded east. But once over water again, it began bouncing along the sea near Rathlin Island, losing its flotation bags after an unsuccessful attempt to land on a beach on the island. The two adventurers jumped into the sea as the disabled balloon went down within sight of their landing target on the coast of western Scotland. They were pulled from the sea by Royal Navy rescue teams about 37 hours after they took off from Maine. Branson was quickly picked up by a helicopter, but Lindstrand, without a life vest, spent more than two hours swimming against strong currents in the cold water before he was found.

1989 15:22:00 GMT
USSR launched the Nadezhda 1 civilian maritime navigation satellite from Plesetsk, positioned in plane 11 of the constellation, which carried a COSPAS/SARSAT search and rescue package.

1991 02:32:00 GMT
The US Air Force launched Navstar 2A-02 (USA 71) from Cape Canaveral, Florida, a GPS Block 2A Global Positioning System satellite placed in Plane D Slot 1. The launch also carried Losat X (Low Altitude Satellite Experiment), a test flight of DoD sensors.

1995 07:09:45 EDT (GMT -4:00:00)
NASA's STS 71 (Atlantis) undocked from the Russian Mir space station, completing the first joint Shuttle-Mir mission.

STS 71 was originally targeted for launch in late May, but slipped into June to accommodate Russian space program activities necessary for the first Space Shuttle/Mir Space Station docking, including a series of spacewalks to reconfigure the station for docking, and launch of a new Spektr module to Mir containing US research hardware. The launch set for 23 June was scrubbed when rainy weather and lightning prevented loading of the external tank earlier that day. The second try on 24 June was scrubbed at the T-9 minute mark, again due to persistent stormy weather in central Florida, coupled with a short (10 minute) launch window. The liftoff was re-set for 27 June 1995, and the final countdown proceeded smoothly.

STS 71 marked a number of historic achievements in human spaceflight history: the 100th US human space launch conducted from Cape Canaveral; the first US Space Shuttle-Russian Space Station Mir docking and joint on-orbit operations; the largest spacecraft ever in orbit; and the first on-orbit changeout of a Shuttle crew.

Docking occurred on 29 June at 9 a.m. EDT, using an R-Bar (Earth radius vector) approach, with Atlantis closing in on Mir from directly below. The R-bar approach allows natural forces to brake the orbiter's approach more than would occur along a standard approach from directly in front of the space station. An R-bar approach also minimizes the number of orbiter jet firings needed for the approach. The manual phase of docking began with Atlantis about half a mile below Mir, with Gibson at the controls on the aft flight deck. Stationkeeping was performed when the orbiter was about 250 feet from Mir, pending approval from Russian and US flight directors to proceed. Gibson then maneuvered the orbiter to a point at about 30 feet from Mir before beginning the final approach to the station. The closing rate was near the targeted 0.1 feet per second, and the closing velocity was approximately 0.107 feet per second at contact. The interface contact was nearly flawless, with less than one inch of lateral misalignment, and an angular misalignment of less than 0.5 degrees per axis. Docking occurred about 216 nautical miles above Lake Baykal region of the Russian Federation. The Orbiter Docking System (ODS) with an Androgynous Peripheral Docking System served as the actual connection point to a similar interface on the docking port on Mir's Krystall module. The ODS was located in Atlantis' forward payload bay, and performed flawlessly during the docking sequence.

When linked, Atlantis and Mir formed largest human spacecraft ever in orbit, with a total mass of almost one half million pounds (about 225 tons) orbiting some 218 nautical miles above the Earth. After hatches on each side opened, the STS 71 crew passed into Mir for a welcoming ceremony. On same day, the Mir 18 crew officially transferred responsibility for station to the Mir 19 crew, and two crews switched spacecraft.

For next five days, about 100 hours total, joint US-Russian operations were conducted, including biomedical investigations, and transfer of equipment to and from Mir. Fifteen separate biomedical and scientific investigations were conducted, using the Spacelab module installed in the aft portion of Atlantis' payload bay, and covering seven different disciplines: cardiovascular and pulmonary functions; human metabolism; neuroscience; hygiene, sanitation and radiation; behavioral performance and biology; fundamental biology; and microgravity research. The Mir 18 crew served as test subjects for the investigations. The three Mir 18 crew members also carried out an intensive program of exercise and other measures to prepare for re-entry into the gravity environment of Earth after more than three months in space.

Numerous medical samples, as well as disks and cassettes, were transferred to Atlantis from Mir, including more than 100 urine and saliva samples, about 30 blood samples, 20 surface samples, 12 air samples, several water samples and numerous breath samples taken from the Mir 18 crew members. Also moved into the orbiter was a broken Salyut-5 computer. Transferred to Mir were more than 1,000 pounds of water generated by the orbiter for waste system flushing and electrolysis; specially designed spacewalking tools for use by the Mir 19 crew during a spacewalk to repair a jammed solar array on the Spektr module; and oxygen and nitrogen from the Shuttle's environmental control system to raise the air pressure on the station, requested by the Russians to improve the Mir consumables margin.

The two spacecraft undocked on 4 July, following a farewell ceremony, with the Mir hatch closing at 3:32 pm EDT on 3 July, and the hatch on the Orbiter Docking System being shut 16 minutes later. Gibson compared the separation sequence to a "cosmic" ballet: Prior to the Mir-Atlantis undocking, the Mir 19 crew temporarily abandoned the station, flying 100 meters away in their Soyuz (TM-21) spacecraft so they could record images of Atlantis and Mir separating. As Atlantis began its flyaround at a distance of 210 meters, Soyuz redocked with the Kvant module, about a minute early. Just prior to the redocking, one of Mir's attitude control computers crashed, putting Mir in free drift, although this was not considered a serious problem. At 12:35 GMT, Atlantis completed its 360 degree flyaround and ignited its engines for the separation burn, while sending back spectacular TV images of the Mir complex.

After undocking from Mir, Atlantis spent several days on orbit, carrying out medical research work with the Spacelab-Mir module in the cargo bay.

The returning crew of eight equaled the largest crew (STS 61-A, October 1985) in Shuttle history. To ease their re-entry into the gravity environment after more than 100 days in space, Mir 18 crew members Thagard, Dezhurov and Strekalov lay supine in custom made recumbent seats installed prior to landing in the orbiter middeck.

Inflight problems included a glitch with General Purpose Computer 4 (GPC 4), which was declared failed when it did not synchronize with GPC 1. Subsequent troubleshooting indicated it was an isolated event, and GPC 4 operated satisfactorily for the remainder of mission.

STS 71 ended on 7 July 1995 when Atlantis landed on revolution 153 on Runway 15, Kennedy Space Center, Florida. Rollout distance: 8,364 feet (2,549 meters). Rollout time: 51 seconds. Orbit altitude: 170 nautical miles. Orbit inclination: 51.6 degrees. Mission duration: nine days, 19 hours, 22 minutes, 17 seconds. Miles Traveled: 4.1 million. The runway was switched from 33 to 15 about 20 minutes before touchdown due to concerns of Chief Astronaut Robert Cabana, flying a Shuttle Training Aircraft, about clouds blocking the runway landing aids from view. After landing, President Clinton phoned congratulations to the crew for their successful mission, and extended an invitation to visit the White House.

The flight crew for STS 71 was: Robert L. Gibson, Commander; Charles J. Precourt, Pilot; Ellen S. Baker, Mission Specialist; Bonnie J. Dunbar, Mission Specialist; Gregory J. Harbaugh, Mission Specialist; Anatoly Solovyev (returned in Soyuz TM-21); Nikolai Budarin (returned in Soyuz TM-21); Norman E. Thagard returned from Mir (launched on Soyuz TM-21); Vladimir Dezhurov returned from Mir (launched on Soyuz TM-21); Gennadiy Strekalov returned from Mir (launched on Soyuz TM-21).

1997 16:56:55 GMT
NASA's Mars Pathfinder spacecraft landed in the Ares Vallis region of Mars, the first US space probe to land on the planet in more than two decades, and returned images of surface.

Mars Pathfinder was launched 4 December 1996, the second of NASA's low-cost planetary Discovery missions. The mission consists of a stationary lander and a surface rover, with the primary objective of demonstrating the feasibility of low-cost landings on and exploration of the Martian surface. This objective was met by tests of communications between the rover and lander, and the lander and Earth, tests of the imaging devices and sensors, and tests of the maneuverability and systems of the rover on the surface. The scientific objectives include atmospheric entry science, long-range and close-up surface imaging, rock and soil composition and material properties experiments, and meteorology, with the general objective being to characterize the Martian environment for further exploration. (Mars Pathfinder was formerly known as the Mars Environmental Survey (MESUR) Pathfinder.)

The spacecraft entered the Martian atmosphere on 4 July 1997 directly from its approach hyperbola at about 7300 m/s without going into orbit around the planet. The cruise stage was jettisoned 30 minutes before atmospheric entry. The lander took atmospheric measurements as it descended. The entry vehicle's heat shield slowed the craft to 400 m/s in about 160 seconds. A 12.5 meter parachute was deployed at this time, slowing the craft to about 70 m/s. The heat shield was released 20 seconds after parachute deployment, and the bridle, a 20 meter long braided Kevlar tether, deployed below the spacecraft. The lander separated from the backshell and slid down to the bottom of the bridle over about 25 seconds. At an altitude of about 1.6 km, the radar altimeter acquired the ground, and about 10 seconds before landing four air bags inflated in about 0.3 seconds forming a 5.2 meter diameter protective 'ball' around the lander. Four seconds later at an altitude of 98 m the three solid rockets, mounted in the backshell, fired to slow the descent, and about 2 seconds later the bridle was cut 21.5 m above the ground, releasing the airbag-encased lander. The lander dropped to the ground in 3.8 seconds and impacted at 16:56:55 UT (12:56:55 p.m. EDT) on 4 July 1997 at a velocity of 18 m/s - approximately 14 m/s vertical and 12 m/s horizontal - and bounced about 12 meters (40 feet) into the air, bouncing at least another 15 times and rolling before coming to rest approximately 2.5 minutes after impact and about 1 km from the initial impact site.

After landing, the airbags deflated and were retracted. Pathfinder opened its three metallic triangular solar panels (petals) 87 minutes after landing. The lander first transmitted the engineering and atmospheric science data collected during entry and landing, the first signal being received at Earth at 18:34 UT (2:34 p.m. EDT). The imaging system obtained views of the rover and immediate surroundings and a panoramic view of the landing area and transmitted it to Earth at 23:30 UT. After some maneuvers to clear an airbag out of the way, ramps were deployed and the rover, stowed against one of the petals, rolled onto the surface on 6 July at about 05:40 UT (1:40 a.m. EDT).

The bulk of the lander's task was to support the rover by imaging rover operations and relaying data from the rover to Earth. The lander was also equipped with a meteorology station. Over 2.5 meters of solar cells on the lander petals, in combination with rechargeable batteries, powered the lander. The lander on-board computer is based on 32-bit architecture with 4 million bytes of static random access memory and 64 million bytes of mass memory for storing images. The main lander components are held in a tetrahedral shaped unit in the center of the three petals, with three low-gain antennas extending from three corners of the box and a camera extending up from the center on a 0.8 meter high pop-up mast. Images were taken and experiments performed by the lander and rover until 27 September 1997 when communications were lost for unknown reasons.

2005 05:45:00 GMT
The 370 kg impactor component of NASA's Deep Impact probe collided with comet Tempel 1, as scheduled, in an experiment to gain more information about the make up of comets. The event was confirmed 7m26s later when the probe's transmissions reached Earth.

The goals of the Deep Impact mission were to rendezvous with comet 9P/Tempel 1 and launch a projectile into the comet nucleus. This objective was achieved on 4 July 2005 at approximately 0545 GMT. Observations were made of the ejecta (much of which represented pristine material from the interior of the comet), the crater formation process, the resulting crater, and any outgassing from the nucleus, particularly the newly exposed surface. The scientific objectives of the mission were to: improve the knowledge of the physical characteristics of cometary nuclei and directly assess the interior of cometary nucleus; determine properties of the surface layers such as density, strength, porosity, and composition from the crater and its formation; study the relationship between the surface layers of a cometary nucleus and the possibly pristine materials of the interior by comparison of the interior of the crater with the surface before impact; and improve our understanding of the evolution of cometary nuclei, particularly their approach to dormancy, by comparing the interior and the surface. The project was selected as a Discovery class mission in July 1999.

Deep Impact was launched on 12 January 2005 from Cape Canaveral, Florida, on a Delta II booster. The spacecraft transferred into a heliocentric orbit to rendezvous with comet P/Tempel 1 on 4 July 2005. Deep Impact was about 880,000 km from the comet on 3 July 2005, moving at 10.2 km/s relative to the comet, when the projectile was released and the flyby spacecraft executed a maneuver to slow down by 120 m/s and divert by 6 m/s. On 4 July, the impactor struck the sunlit side of the comet nucleus approximately 24 hours after release, at 0545 UT. At 10.2 km/s velocity, the impactor had an impact energy of about 19 gigajoules, and was expected to form a crater roughly 25 meters deep and 100 meters wide. (The estimate was based on models of comet structure and subject to large uncertainty.) Material from the nucleus were ejected into space, and the impactor and much of the ejecta vaporized.

The flyby spacecraft was approximately 10,000 km away at the time of impact and began imaging 60 seconds earlier. At 600 seconds after impact, the spacecraft was about 4000 km from the nucleus and observations of the crater began and continued up to a range of about 700 km, about 50 seconds before closest approach. At this point (about 961 seconds after impact), imaging ended as the spacecraft reoriented itself by 45 degrees to optimize protection from dust damage as it flew by the nucleus. Closest approach to the nucleus was at a distance of about 500 km. At 1270 seconds, the crossing of the inner coma was complete and the spacecraft oriented itself to look back at the comet and begin imaging again. At 3000 seconds, the spacecraft began playback of data to Earth at 20 to 200 kilobits per second. The comet and spacecraft were about 0.89 AU from Earth and 1.5 AU from the Sun during the encounter. Selected impactor and flyby images and spectra were returned in real time to Earth during the encounter. Primary data was returned over the first day after encounter, with a 28 day supplemental data return period. Earth-based observatories also studied the impact. The spacecraft ranged over a distance of 0.93 to 1.56 AU from the Sun during the mission.

The end of the mission was originally scheduled for August 2005, and a subsequent extended mission included another comet flyby and observations of planets around other stars that lasted from July 2007 to December 2010. After almost 9 years in space and the return of approximately 500,000 images of celestial objects, the project team at NASA's Jet Propulsion Laboratory in Pasadena, California, reluctantly pronounced the mission at an end on 20 September 2013 after being unable to communicate with the spacecraft for over a month. The last communication with the probe was Aug. 8. Deep Impact was history's most traveled comet research mission, going about 4.71 billion miles (7.58 billion kilometers).

The Deep Impact spacecraft consisted of a 370 kg cylindrical copper impactor attached to a 650 kg flyby bus. The spacecraft was a box-shaped honeycomb aluminum framework with a flat rectangular Whipple debris shield mounted on one side to protect components during close approach to the comet. Body-mounted on the framework were one high- and one medium-resolution instrument, each consisting of an imaging camera and an infrared spectrometer, used to observe the ejected ice and dust. The medium resolution camera had a field of view (FOV) of 0.587 degrees and a resolution of 7 m/pixel at 700 km distance and was used for navigation and context images. The high resolution camera had a FOV of 0.118 degrees and a resolution of 1.4 m/pixel at 700 km. The infrared spectrometers covered the range from 1.05 to 4.8 micrometers with FOV of 0.29 degrees (hi-res) and 1.45 degrees (lo-res). The total flyby bus instrument payload had a mass of 90 kg and used an average of 92 W during encounter.

The impactor projectile was made of primarily copper (49%) and 24% aluminum, so it would be easily identifiable in the observed collision debris, and minimize contamination in the spectra after the projectile was largely vaporized and mixed in with the comet ejecta on impact. The impactor was a short hexagonal cylinder built above the copper cratering mass with a small hydrazine propulsion system for targeting which could provide delta-V of 25 m/s. Targeting was accomplished using a high-precision star-tracker, auto-navigation algorithms, and the Impactor Targeting Sensor (ITS), a camera which provided images for autonomous control and targeting. The ITS was operated until impact, and images were sent back to Earth via the flyby spacecraft. The impactor was mechanically and electrically connected to the flyby spacecraft until 24 hours prior to encounter. After separation, it ran on internal battery power.

Comet 9P/Tempel 1 is a periodic comet which orbits the Sun every 5.51 years. It has a semi-major axis of 3.12 astronomical units (AU, the distance from the Sun to the Earth) and a perihelion distance of 1.5 AU, between the orbits of Mars and Jupiter, in an orbit inclined 10.5 degrees to the ecliptic. The orbit has changed in the past, but its perihelion has been within 10 AU for at least 300,000 years. The nucleus is estimated to be roughly 14 km long and 4 km wide. Perihelion for the current orbit occured on 5 July 2005, the day after the encounter. The comet was discovered on 3 April 1867 by Ernst Wilhelm Leberecht Tempel, and was first recognized to be periodic in May of that year by C. Bruhns.

To view a movie of the collision, from the impactor's perspective, see

See also
See also

Deep Impact impactor colliding with comet Tempel 1, observed by the flyby spacecraft, NASA photo

NASA's Curiosity rover began a southwestward trek toward the lower layers of Mount Sharp, the main destination for the mission.

NASA's Mars Science Laboratory spacecraft launched from Cape Canaveral Air Force Station, Florida, at 15:02:00 UTC (10:02AM EST) on 26 November 2011. The spacecraft flight system had a launch mass of 3,893 kg (8,583 lb), consisting of an Earth-Mars fueled cruise stage (539 kg (1,188 lb)), the entry-descent-landing (EDL) system (2,401 kg (5,293 lb) including 390 kg (860 lb) of landing propellant), and an 899 kg (1,982 lb) mobile rover with an integrated instrument package. On 11 January 2012, the spacecraft successfully refined its trajectory with a three-hour series of thruster-engine firings, advancing the rover's landing time by about 14 hours.

Selection of Gale Crater for the landing during preflight planning had followed consideration of more than thirty locations by more than 100 scientists participating in a series of open workshops. The selection process benefited from examining candidate sites with NASA's Mars Reconnaissance Orbiter and earlier orbiters, and from the rover mission's capability of landing within a target area only about 20 kilometers (12 miles) long. That precision, about a fivefold improvement on earlier Mars landings, made sites eligible that would otherwise be excluded for encompassing nearby unsuitable terrain. The Gale Crater landing site, about the size of Connecticut and Rhode Island combined, is so close to the crater wall and Mount Sharp that it would not have been considered safe if the mission were not using this improved precision.

Science findings began months before landing as Curiosity made measurements of radiation levels during the flight from Earth to Mars that will help NASA design for astronaut safety on future human missions to Mars.

The Mars rover Curiosity landed successfully on the floor of Gale Crater at 05:32 UTC on 6 August 2012, at 4.6 degrees south latitude, 137.4 degrees east longitude and minus 4,501 meters (2.8 miles) elevation. Engineers designed the spacecraft to steer itself during descent through Mars' atmosphere with a series of S-curve maneuvers similar to those used by astronauts piloting NASA space shuttles. During the three minutes before touchdown, the spacecraft slowed its descent with a parachute, then used retrorockets mounted around the rim of its upper stage. The parachute descent was observed by the Mars Reconnaissance Orbiter, see for the image and some notes. In the final seconds of the landing sequence, the upper stage acted as a sky crane, lowering the upright rover on a tether to land on its wheels. The touchdown site, Bradbury Landing, is near the foot of a layered mountain, Mount Sharp (Aeolis Mons). Curiosity landed on target and only 2.4 km (1.5 mi) from its center.

Some low resolution Hazcam images were immediately sent to Earth by relay orbiters confirming the rover's wheels were deployed correctly and on the ground. Three hours later, the rover began transmitting detailed data on its systems' status as well as on its entry, descent and landing experience. On 8 August 2012, Mission Control began upgrading the rover's dual computers by deleting the entry-descent-landing software, then uploading and installing the surface operation software; the switchover was completed by 15 August. On 15 August, the rover began several days of instrument checks and mobility tests. The first laser test of the ChemCam on Mars was performed on a rock, N165 ("Coronation" rock), on 19 August.

In the first few weeks after landing, images from the rover showed that Curiosity touched down right in an area where water once coursed vigorously over the surface. The evidence for stream flow was in rounded pebbles mixed with hardened sand in conglomerate rocks at and near the landing site. Analysis of Mars' atmospheric composition early in the mission provided evidence that the planet has lost much of its original atmosphere by a process favoring loss from the top of the atmosphere rather than interaction with the surface.

In the initial months of the surface mission, the rover team drove Curiosity eastward toward an area of interest called "Glenelg," where three types of terrain intersect. The rover analyzed its first scoops of soil on the way to Glenelg. In the Glenelg area, it collected the first samples of material ever drilled from rocks on Mars. Analysis of the first drilled sample, from a rock target called "John Klein," provided the evidence of conditions favorable for life in Mars' early history: geological and mineralogical evidence for sustained liquid water, other key elemental ingredients for life, a chemical energy source, and water not too acidic or too salty.

Within the first eight months of a planned 23-month primary mission, Curiosity met its major objective of finding evidence of a past environment well suited to supporting microbial life.

On 7 October 2012, a mysterious "bright object" (image) discovered in the sand at Rocknest, drew scientific interest. Several close-up pictures were taken of the object and preliminary interpretations by scientists suggest the object to be "debris from the spacecraft." Further images in the nearby sand detected other "bright particles." The newly discovered objects are presently thought to be "native Martian material". (2015)

On 4 July 2013, Curiosity finished its investigations in the Glenelg area and began a southwestward trek toward an entry point to the lower layers of Mount Sharp. There, at the main destination for the mission, researchers anticipate finding further evidence about habitable past environments and about how the ancient Martian environment evolved to become much drier. As of 29 July 2014, the rover had traveled about 73% of the way, an estimated linear distance of 6.1 km (3.8 mi) of the total 8.4 km (5.2 mi) trip, to the mountain base since leaving its "start" point in Yellowknife Bay. (see also Where is the rover now?)

On 6 August 2013, Curiosity audibly played "Happy Birthday to You" in honor of the one Earth year mark of its Martian landing. This was the first time that a song was played on a foreign planet; making "Happy Birthday" the first song and Curiosity the first device used to play music on a foreign planet. This was also the first time music was transmitted between two planets. On 24 June 2014, Curiosity completed a Martian year (687 Earth days) on Mars.

On 26 September 2013, NASA scientists reported the Mars Curiosity rover detected "abundant, easily accessible" water (1.5 to 3 weight percent) in soil samples at the Rocknest region of Aeolis Palus in Gale Crater.

On 3 June 2014, Curiosity observed the planet Mercury transiting the Sun, marking the first time a planetary transit has been observed from a celestial body besides Earth.

On 11 July 2015, Curiosity's Mars Hand Lens Imager (MAHLI) photographed an extremely unusual high silica rock fragment dubbed "Lamoose" (image). The rock, about 4 inches (10 centimeters) across, is fine-grained, perhaps finely layered, and apparently etched by the wind. [Ed. note: If I were on Mars and had seen this "rock" I would have picked it up to turn it over to see what the other side looks like.] Other nearby rocks in that portion of the "Marias Pass" area of Mt. Sharp also have unusually high concentrations of silica, first detected in the area by the Chemistry & Camera (ChemCam) laser spectrometer. This rock was targeted for follow-up study by the MAHLI and the arm-mounted Alpha Particle X-ray Spectrometer (APXS). Silica is a compound containing silicon and oxygen, commonly found on Earth as quartz. It is a primary raw material for Portland cement, many ceramics such as earthenware, stoneware, and porcelain, and is used in the production of glass for windows, bottles, etc. High levels of silica could indicate ideal conditions for preserving ancient organic material, if they are present. (Press release: NASA's Curiosity Rover Inspects Unusual Bedrock, issued 23 July 2015)

For more information about the Curiosity rover and its continuing science experiments and discoveries, visit NASA's Mars Science Laboratory - Curiosity Web page or the JPL link below.

-Rover Details-

Curiosity has a mass of 899 kg (1,982 lb) including 80 kg (180 lb) of scientific instruments, including equipment to gather and process samples of rocks and soil, distributing them to onboard test chambers inside analytical instruments. It inherited many design elements from previous rovers, including six-wheel drive, a rocker-bogie suspension system, and cameras mounted on a mast to help the mission's team on Earth select exploration targets and driving routes. The rover is 2.9 m (9.5 ft) long by 2.7 m (8.9 ft) wide by 2.2 m (7.2 ft) in height. NASA's Jet Propulsion Laboratory (JPL), Pasadena, California, builder of the Mars Science Laboratory, engineered Curiosity to roll over obstacles up to 65 centimeters (25 inches) high and to travel about 200 meters (660 feet) per day on Martian terrain at a rate up to 90 m (300 ft) per hour.

Curiosity is powered by a radioisotope thermoelectric generator (RTG), producing electricity from the heat of plutonium-238's radioactive decay. The RTG gives the mission an operating lifespan on the surface of "a full Mars year (687 Earth days) or more." At launch, the generator provided about 110 watts of electrical power. Warm fluids heated by the generator's excess heat are plumbed throughout the rover to keep electronics and other systems at acceptable operating temperatures. Although the total power from the generator will decline over the course of the mission, it was still providing 105 or more watts a year after landing; it is expected to still be supplying 100 watts after ten years.

Curiosity is equipped with several means of communication, an X band small deep space transponder for communication directly to Earth via NASA's Deep Space Network and a UHF Electra-Lite software-defined radio for communicating with Mars orbiters. The X-band system has one radio, with a 15 W power amplifier, and two antennas: a low-gain omnidirectional antenna that can communicate with Earth at very low data rates (15 bit/s at maximum range), regardless of rover orientation, and a high-gain antenna that can communicate at speeds up to 32 kbit/s, but must be aimed. The UHF system has two radios (approximately 9 W transmit power), sharing one omnidirectional antenna. This can communicate with the Mars Reconnaissance Orbiter (MRO) and Odyssey orbiter (ODY) at speeds up to 2 Mbit/s and 256 kbit/s, respectively, but each orbiter is only able to communicate with Curiosity for about 8 minutes per day. The orbiters have larger antennas and more powerful radios, and can relay data to earth faster than the rover could do directly. Therefore, most of the data returned by Curiosity is via the UHF relay links with MRO and ODY. The data return via the communication infrastructure as implemented at MDL, and the rate observed during the first 10 days was approximately 31 megabytes per day. In 2013, after the first year since Curiosity's landing, the orbiters had already downlinked 190 gigabits of data from Curiosity.

Typically 225 kbit/day of commands are transmitted to the rover directly from Earth, at a data rate of 1–2 kbit/s, during a 15-minute (900 second) transmit window, while the larger volumes of data collected by the rover are returned via satellite relay. The one-way communication delay with Earth varies from 4 to 22 minutes, depending on the planets' relative positions.

-Science Payload-

In April 2004, NASA solicited proposals for specific instruments and investigations to be carried by Mars Science Laboratory. The agency selected eight of the proposals later that year and also reached agreements with Russia and Spain to carry instruments those nations provided. Curiosity carries the most advanced payload of scientific gear ever used on Mars' surface, a payload more than 10 times as massive as those of earlier Mars rovers. More than 400 scientists from around the world participate in the science operations.

A suite of instruments named Sample Analysis at Mars (SAM) analyzes samples of material collected and delivered by the rover's arm, plus atmospheric samples. It includes a gas chromatograph, a mass spectrometer and a tunable laser spectrometer with combined capabilities to identify a wide range of carbon-containing compounds and determine the ratios of different isotopes of key elements. Isotope ratios are clues to understanding the history of Mars' atmosphere and water.

An X-ray diffraction and fluorescence instrument called CheMin also examines samples gathered by the robotic arm. It is designed to identify and quantify the minerals in rocks and soils, and to measure bulk composition.

Mounted on the arm, the Mars Hand Lens Imager takes extreme close-up pictures of rocks, soil and, if present, ice, revealing details smaller than the width of a human hair. It can also focus on hard-to-reach objects more than an arm's length away and has taken images assembled into dramatic self-portraits of Curiosity.

Also on the arm, the Alpha Particle X-ray Spectrometer determines the relative abundances of different elements in rocks and soils.

The Mast Camera, mounted at about human-eye height, images the rover's surroundings in high-resolution stereo and color, with the capability to take and store high definition video sequences. It can also be used for viewing materials collected or treated by the arm.

An instrument named ChemCam uses laser pulses to vaporize thin layers of material from Martian rocks or soil targets up to 7 meters (23 feet) away. It includes both a spectrometer to identify the types of atoms excited by the beam, and a telescope to capture detailed images of the area illuminated by the beam. The laser and telescope sit on the rover's mast and share with the Mast Camera the role of informing researchers' choices about which objects in the area make the best targets for approaching to examine with other instruments.

The rover's Radiation Assessment Detector characterizes the radiation environment at the surface of Mars. This information is necessary for planning human exploration of Mars and is relevant to assessing the planet's ability to harbor life.

In the two minutes before landing, the Mars Descent Imager captured color, high-definition video of the landing region to provide geological context for the investigations on the ground and to aid precise determination of the landing site. Pointed toward the ground, it can also be used for surface imaging as the rover explores.

Spain's Ministry of Education and Science provided the Rover Environmental Monitoring Station to measure atmospheric pressure, temperature, humidity, winds, plus ultraviolet radiation levels.

Russia's Federal Space Agency provided the Dynamic Albedo of Neutrons instrument to measure subsurface hydrogen up to 1 meter (3 feet) below the surface. Detections of hydrogen may indicate the presence of water bound in minerals.

In addition to the science payload, equipment of the rover's engineering infrastructure contributes to scientific observations. Like the Mars Exploration Rovers, Curiosity has a stereo Navigation Camera on its mast and low-slung, stereo Hazard-Avoidance cameras. The wide view of the Navigation Camera is also used to aid targeting of other instruments and to survey the sky for clouds and dust. Equipment called the Sample Acquisition/Sample Preparation and Handling System includes tools to remove dust from rock surfaces, scoop up soil, drill into rocks to collect powdered samples from rocks' interiors, sort samples by particle size with sieves, and deliver samples to laboratory instruments.

The Mars Science Laboratory Entry, Descent and Landing Instrument Suite was a set of engineering sensors that measured atmospheric conditions and performance of the spacecraft during the arrival-day plunge through the atmosphere, to aid in design of future missions.

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