Voyager 2's Epic Journey Begins

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Thirty-five years ago today — August 20, 1977 — the Voyager 2 space probe launched from Cape Canaveral aboard a Titan-IIIE-Centaur rocket.


(Voyager 2. NASA image.)

Voyager 2 was actually the first of the Voyager spacecraft to be launched. Voyager 1 would be launched a little over two weeks later.

The Voyager mission had at first been named “Mariner Jupiter/Saturn,” and was itself a less ambitious mission than originally planned:

Originally planned as a Grand Tour of the outer planets, including dual launches to Jupiter, Saturn, and Pluto in 1976-77 and dual launches to Jupiter, Uranus, and Neptune in 1979, budgetary constraints caused a dramatic rescoping of the project to two spacecraft, each of which would go to only Jupiter and Saturn.

The mission succeeded beyond all expectations, however:

Voyager 2’s launch date had preserved one part of the original Grand Tour design, i.e. the possibility of an extended mission to Uranus and Neptune. Despite the difficulties encountered, scientists and engineers had been able to make Voyager enormously successful. As a result, approval was granted to extend the mission, first to Uranus, then to Neptune and later to continue observations well past Neptune.

The extended mission required controllers to upload new software to take into account the communication lag times and the lower light levels in the outer solar system, but Voyager 2’s systems continued to work superbly. Our space history series has already noted Voyager 2’s successful visits to Jupiter, Saturn, Uranus, and Neptune.

Now known as the Voyager Interstellar Mission, Voyager 2 is currently over 99.35 astronomical units from the sun … and still going.

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August 14: Sons of Liberty Day

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On August 14, 1765, the recently-formed “Sons of Liberty” made themselves known in a very public way.

Starting as “the Loyal Nine,” the group formed in Boston in the summer of 1765 in response to the Stamp Act. By August their agitation produced a violent response, when on the 14th a mob burned the Stamp Distributor in effigy and ransacked his home. Four years later, the Sons of Liberty gathered at Boston’s “Liberty Tree” to commemorate the event and one of the participants compiled a list of those present.

According to this USHistory.org page, however, “The success of these movements in undermining the Stamp Act cannot be attributed to violence alone. Their most effective work was performed in newsprint [as] accounts of the most dramatic escapades spread throughout the colonies.”

The most famous of the Sons of Liberty’s escapades was the Boston Tea Party on December 16, 1773. That particular protest contrasts with recent protests we’ve seen ….


(Click for larger version.)

Well might we ask ourselves, who are today’s true-born Sons of Liberty? And for what liberty do they fight?

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Measuring Some of the Hazards of Spaceflight

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Forty years ago today — August 13, 1972 — Explorer 46 launched from Wallops Island, Virginia, atop a Scout rocket.


(Refurbished backup Meteoroid Technology Satellite. National Air & Space Musuem image.)

Also known as the Meteoroid Technology Satellite, the spacecraft was built to measure meteoroid velocity, distribution, and penetration in target panels that extended from the body of the vehicle. According to this National Air & Space Musuem archival page, the satellite recorded twenty meteoroid and over two thousand micrometeoroid impacts through December 1972.

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Pioneering High-Energy Astronomy

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Thirty-five years ago today — August 12– High-Energy Astronomy Observatory 1 (HEAO 1) was launched by an Atlas Centaur from Cape Canaveral.


(X-ray source catalog from HEAO-1’s all-sky survey. NASA image.)

HEAO 1 was the first satellite in a series of three to study X-ray and gamma-ray sources. HEAO 1, in particular,

was specifically designed to map and survey the celestial sphere for X-ray and gamma-ray sources in the energy range of 150 eV to 10 MeV, to establish the size and precise location of X-ray sources to determine the contribution of discrete sources to the X-ray background, and to measure time variations of X-ray sources.

The HEAO 1 observatory was capable of scanning the entire celestial sphere in 6 months, but failure of some of the detector components meant the complete survey took longer than planned. In addition, the instruments had to be turned off when passing through the inner Van Allen radiation belt to protect itself from damage. The mission lasted until January 9, 1979, during which HEAO 1 compiled a comprehensive catalog of X-ray sources, classified several hundred X-ray source with their visible-light companions, and discovered the first X-ray eclipse in a low-mass binary star.

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First Dual-Spacecraft Flight, 50 Years Ago

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Fifty years ago today — August 11, 1962 — the USSR launched Vostok 3 from the Baikonur Cosmodrome. The very next day, they launched Vostok 4, marking the first time two crewed space vehicles were in orbit at the same time.

Vostok 3 carried cosmonaut Andrian G. Nikolayev, and Vostok 4 carried cosmonaut Pavel R. Popovich. The closest approach between their two spacecraft was about 5 km. Both spacecraft de-orbited on August 15th.

The best online images of the Vostok 3 & 4 mission seem to be held closely by the web site owners, but: playing off the “Vostok” theme, and since we’ve been captivated by the Curiosity rover’s recent landing on Mars, the image below shows the track of one of Curiosity’s predecessor’s near Vostok Crater.


(Mars Rover Opportunity’s track near Vostok crater. NASA image.)

A 360-degree view extending from the above image can be seen in this panoramic view.

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Surveying the Ocean's Topography, from Space

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Twenty years ago today — August 10, 1992 — an Ariane 42P launch vehicle launched from Kourou, French Guiana, carrying the TOPEX/Poseidon satellite.


(TOPEX/Poseidon. NASA image.)

Officially the Ocean Topography Experiment, TOPEX/Poseidon was a joint mission between NASA and France’s Centre National d’Etudes Spatiales to measure sea-surface heights from a space-based radar platform. It was also the second spacecraft in the “Mission to Planet Earth” program.

The TOPEX/Poseidon spacecraft was decommissioned in January 2006, but the Jason-1 and Jason-2 follow-on spacecraft are continuing the mission. The Ocean Surface Topography page presents details on all of the missions associated with the space-based study of our world’s oceans.

So, next time you’re at the beach and thinking about how high the waves are, remember that satellites hundreds of miles above you are looking down, thinking about the same thing.

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A Shuttle Flight More Than Two Decades in the Making

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Five years ago today — August 8, 2007 — the Space Shuttle Endeavour launched from Kennedy Space Center on an International Space Station construction mission.


(Mission specialist Barbara Morgan on the shuttle’s middeck during STS-118. NASA image.)

On mission STS-118, U.S. astronauts Scott J. Kelly, Charles O. Hobaugh, Richard A. Mastracchio, Barbara R. Morgan, Tracy E. Caldwell, and Benjamin Alvin Drew, along with Canadian astronaut Dafydd (Dave) Williams, delivered and installed a new truss segment to the ISS. They also replaced a failed control moment gyro — part of the attitude control system that keeps the station in the correct orientation — and transferred supplies for the station residents.

Astronaut Morgan was originally Christa McAuliffe’s back-up for the STS-51L mission that ended when the Challenger was destroyed. The June 2007 mission overview for STS-118 explained,

Morgan trained side by side with McAuliffe and witnessed the 1986 Challenger accident in which McAuliffe and her six fellow crew members died. The Teacher in Space Project was suspended then, but Morgan held on to her NASA ties. In the months following that tragedy, she went on the visits McAuliffe would have made, talking to children and teachers all over the country. Then, when she was selected in 1998 to become a full-fledged astronaut, she jumped at the opportunity.

In 2002, Morgan was chosen as the first educator to become a mission specialist astronaut. The Educator Astronaut Project evolved from the Teacher in Space Project. Both aimed to engage and attract students to explore the excitement and wonder of spaceflight and to inspire and support educators. Morgan’s primary duty is the same as it is for the entire crew — accomplish the planned objectives of the station assembly mission.

She had been selected as the Teacher in Space backup candidate in July 1985, and so waited 22 years for her space mission. No wonder she looks happy, though it must have been somewhat bittersweet.

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Mission to Planet Earth

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Fifteen years ago today — August 7, 1997 — the Space Shuttle Discovery launched from the Kennedy Space Center on a mission to study the Earth’s atomosphere from space.


(Discovery‘s payload bay, outfitted with experimental packages for STS-85. NASA image.)

Astronauts Curtis L. Brown, Jr., Kent V. Rominger, N. Jan Davis, Robert L. Curbeam, Jr., Stephen K. Robinson, and Canadian Space Agency astronaut Bjarni Y.Tryggvason made up the crew of mission STS-85. Their mission was the second to carry the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere, Shuttle Pallet Satellite (with the unwieldy acronym CRISTA-SPAS) as part of the “Mission to Planet Earth.” They deployed the pallet shortly after reaching orbit, and retrieved it on August 16th.

STS-85 also carried the Japanese Manipulator Flight Development (MFD) system; two “hitchhiker” payloads, Technology Applications and Science-01 (TAS-1) and the International Extreme Ultraviolet Hitchhiker-02 (IEH-02), and a variety of smaller experiment packages in the main cabin. The crew “also worked with the Orbiter Space Vision System (OSVS), which [was] used during ISS assembly.” They returned to Earth on August 19th.

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Curiosity Has Landed

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A few hours ago the Mars Science Laboratory, also known as the Curiosity rover, landed successfully on the red planet.


(One of Curiosity’s first pictures from Mars. According to the official NASA description, this image was “taken through a ‘fisheye’ wide-angle lens on the left ‘eye’ of a stereo pair of Hazard-Avoidance cameras on the left-rear side of the rover. The image is one-half of full resolution. The clear dust cover that protected the camera during landing has been sprung open. Part of the spring that released the dust cover can be seen at the bottom right, near the rover’s wheel.”)

Here’s the full story from Spaceflight Now. Congratulations to the spacecraft’s designers, builders, launch team, and operators on the pinpoint approach and the success of the “sky crane” that deposited the rover safely on the surface. Well done!

The rover landed in Gale Crater, which pleases me immensely since the main character of my novel is named Gale (nicknamed “Stormie”). I may need to add a suitable reference in the text.

As I wrote in a recent related post, I look forward to Curiosity’s trek and discoveries.

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Anticipating a Mars Landing, Remembering A Mars Lander

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As we get ready for the landing of the Curiosity rover, a bit of space history: 5 years ago today — August 4, 2007 — a Delta II rocket launched from Cape Canaveral carrying the Phoenix Mars Lander.


(Phoenix Mars Lander. NASA conceptual image.)

The Phoenix was designed to analyze soil samples dug from below the Martian surface. It landed in Mars’ north polar region on 25 May 2008:

Fourteen minutes before touchdown, and about 7 minutes before atmospheric entry (defined as reaching an altitude of 125 km) the cruise stage was jettisoned. The spacecraft entered the atmosphere and the heat shield initially slowed the craft. After about 3 minutes the parachute deployed, followed by ejection of the heat shield 15 seconds later, deployment of landing legs 10 seconds after that, and radar activation 50 seconds later. At 1 km altitude the parachute was released and a powered descent and soft-landing was achieved using a pulsed propulsion system with 8 thrusters, which turned off when footpad sensors detected touchdown.

In terms of the Martian year, the spacecraft landed near the summer solstice, at a high enough latitude that the sun would be above the horizon for several more months. This provided ample power through the summer months, but ensured that when winter came the craft would not be able to replenish its batteries. As a result, the mission came to an end when the lander sent its last transmission on 2 November 2008. And according to this mission page, Mars Reconnaissance Orbiter images taken in 2010 showed that winter snow and ice damaged the lander’s solar panels.

Phoenix confirmed the presence of water ice on Mars, and also determined that the Martian soil is moderately alkaline.

And as we post this, the Mars Science Laboratory, Curiosity, is on course for the red planet. We look forward to the landing, and some new discoveries!

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