Skylab

Forty years ago today — May 14, 1973 — the last operational Saturn V rocket lifted off from the Kennedy Space Center and carried the Skylab space station to orbit.


(Skylab. NASA image.)

Skylab was “composed of five parts, the Apollo telescope mount (ATM), the multiple docking adapter (MDA), the airlock module (AM), the instrument unit (IU), and the orbital workshop (OWS).”

The “telescope mount” — positioned at a right angle to the main body, as seen in the image — pointed at the sun, and provided some spectacular images of solar activity in addition to being the primary reference point for the station’s attitude control subsystem. Technology being what it was at the time, astronauts had to retrieve film from the ATM’s cameras by taking spacewalks to it.

The “workshop”

was a modified Saturn 4B stage suitable for long duration manned habitation in orbit. It contained provisions and crew quarters necessary to support three-person crews for periods of up to 84 days each.

The first crew to inhabit the station launched eleven days after the station itself went into orbit.

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First Asteroid Mission, Triumphant Despite Many Troubles

Ten years ago today — May 9, 2003 — Japan launched a daring asteroid sample-return mission from the Uchinoura Space Center, atop an M-5 rocket.


(Hayabusa. Image from the National Space Science Data Center.)

Originally called Muses-C, Hayabusa (“Falcon”) was a difficult mission to begin with, but experienced a series of setbacks that made its ultimate success all the more impressive.

  • In late 2003, a large solar flare degraded the spacecraft’s solar panels, reducing the power available to its ion engines. The original rendezvous date in early summer 2005 was pushed back to September.
  • On July 31, 2004, Hayabusa’s X-axis reaction wheel failed.
  • The spacecraft successfully rendezvoused with 25143 Itokawa (1998 SF36) — an asteroid  about as big as three football stadiums at 550 x 180 meters (1800 x 590 feet) — on September 12, 2005. Hayabusa established itself in a heliocentric orbit for station-keeping about 20 km (12.4 mi) from the asteroid.
  • On October 3, 2005 Hayabusa’s Y-axis reaction wheel failed, leaving its attitude control subsystem operating only on “one reaction wheel and two chemical thrusters.”
  • Hayabusa mapped the asteroid’s surface in two phases, then began descent operations. During the second touchdown rehearsal on November 12th, the spacecraft released a “lander/hopper” called Minerva; unfortunately, “the release was at a higher altitude than planned…. and it is believed Minerva moved off into space without landing.”
  • A week later, on November 19, Hayabusa again descended toward the asteroid, and released a “target marker” before contact was lost as it fell to the surface.

Later telemetry indicated that Hayabusa hit the surface at 20:40 UT 19 November (5:40 a.m. JST 20 November) at roughly 10 cm/sec and bounced. It bounced again at 21:10 and then landed at 21:30 within about 30 meters of the target marker. At 21:58 (6:58 a.m. JST 20 November) it was commanded to make an emergency ascent. The craft remained on the surface for about half an hour but did not collect a sample. This was the first ever controlled landing on an asteroid and first ascent from any other solar system body except the Moon.

  • On November 25, Hayabusa touched down again, and fired two “sampling bullets” at the surface. Telemetry could not verify that they actually fired; nevertheless, Hayabusa lifted off.
  • On December 9, ground controllers lost contact with the spacecraft, “presumably because of torques caused by a thruster leak which altered the pointing of the antenna.”
  • Controllers restored communication in March 2006, and learned over the next several months that the spacecraft’s status was somewhat grim: low on fuel, two out of three reaction wheels inoperative, plus 4 out of 11 batteries had also stopped working. The spacecraft’s degraded solar cells and batteries were still sufficient to maintain thrust and attitude control with its xenon ion engine, and in April 2007 it started its journey Earth-ward.

When Hayabusa was a little outside the Moon’s orbit, it released its sample return capsule, which de-orbited on June 13, 2010 and landed near Woomera, Australia.

Subsequent examination of the sample return capsule showed that there were roughly 1500 dust particles, presumably from asteroid Itokawa.

Well done, Hayabusa!

You can learn more about this remarkable mission at this Japan Aerospace Exploration Agency (JAXA) page.

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Exploring the Evolution of Galaxies

Ten years ago today — April 28, 2003 — a Pegasus XL rocket carried a small spacecraft to probe the origin of stars and galaxies.


(A 2012 GALEX composite image of the Andromeda galaxy. NASA/JPL-Caltech image.)

Called GALEX, for GALaxy Evolution eXplorer, the spacecraft’s primary instrument was a telescope tuned to the ultraviolet part of the spectrum. With its mission now extended beyond the original 29-month timeline, GALEX is conducting “an all-sky imaging survey, a deep imaging survey, and a survey of 200 galaxies nearest to the Milky Way” in order to explore the origins of heavy elements, stars, and galaxies. You can find more information about the mission, including many stunning images, on this page

For more down-to-earth mapping purposes, on this date 5 years ago India launched CartoSat 2A, a remote-sensing satellite, along with 9 smaller spacecraft, from the Sriharikota launch center on a PSLV 9 rocket. Urban and rural planners use CartoSat’s data.

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P.S. The full resolution JPEG (19.3 MB) of the Andromeda image above is here.

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Shuttle, Soyuz, and Space-Based Navigation

Twenty years ago today — April 26, 1993 — the Space Shuttle Columbia launched from the Kennedy Space Center on an international Spacelab mission.


(Spacelab D-2 in the shuttle payload bay. Note the lightning flashes in the clouds below. NASA image.)

The STS-55 crew consisted of U.S. astronauts Steven R. Nagel, Terence T. Henricks, Jerry L. Ross, Charles J. Precourt, Bernard A. Harris Jr., and Ulrich Walter, plus German astronaut Hans W. Schlegel. The shuttle carried the second of the German-built reusable Spacelab modules, and the crew spent 9 days in space conducting a variety of experiments in the laboratory. One highlight of the mission was the first IV established in orbit, in which Dr. Harris “inject[ed] Schlegel with saline as part of study to replace body fluids lost during adaptation to weightlessness.”

Then, on this date 10 years ago, astronaut Edward T. Lu launched from the Baikonur Cosmodrome on mission Soyuz TMA-2, making him the first U.S. astronaut to serve as the Flight Engineer of a Soyuz spacecraft. The spacecraft commander was cosmonaut Yuri I. Malenchenko, and their destination was the International Space Station where they became the Expedition 7 crew.

Finally, 5 years ago today — April 26, 2008 — a Soyuz-Fregat rocket launched from Baikonur carrying GIOVE-B (Galileo In-Orbit Validation Element-B), the second of two test spacecraft for the European Union’s own fleet of navigational satellites.

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Soft X-Rays and a Data Relay

Twenty years ago today — April 25, 1993 — the first satellite completely sponsored by the Department of Energy launched on a Pegasus booster, dropped from the wing of NASA’s B-52.


(ALEXIS satellite artist’s conception. NASA image from Wikimedia Commons.)

The Array of Low Energy X-Ray Imaging Sensors (ALEXIS) satellite’s primary instrument was an X-ray telescope array tuned to “ultrasoft” X-rays for making a sky map in that part of the electromagnetic spectrum, as well as the “Blackbeard” VHF receiver “for studying the effect of lightning and electromagnetic impulse from exploding [nuclear] devices on the ionospheric transmission.”

During its flight, one of the satellite’s solar array paddles was damaged, and controllers could not establish contact with the spacecraft for 3 months. Once they established contact, they had to develop specific attitude control procedures to bring the satellite under control, after which the spacecraft performed well although “the astronomy data needed a full pointing and aspect solution in order to be interpreted.”

And, to complete the promise implied by the title of this post: 5 years ago today — April 25, 2008 — China launched its first data-relay satellite, Tianlian 1, on a Long March 3C rocket from Xichang Launch Center.

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Neurolab, the Last Spacelab Mission

Fifteen years ago today — April 17, 1998 — the Space Shuttle Columbia launched from the Kennedy Space Center on a unique scientific mission.


(The Spacelab module in the Shuttle cargo bay during mission STS-90. NASA image from Wikimedia Commons.)

The STS-90 crew — Richard A. Searfoss, Scott D. Altman, Richard M. Linnehan, Dafydd Rhys Williams, Kathryn P. Hire, Jay C. Buckey, and James A. Pawelczyk — spent just over 2 weeks in space, operating the “Neurolab” which

targeted one of the most complex and least understood parts of the human body — the nervous system. The primary goals were to conduct basic research in neurosciences and expand understanding of how the nervous system develops and functions in space. Test subjects were crew members and rats, mice, crickets, snails and two kinds of fish.

The crew conducted most of the experiments in the European Space Agency’s pressurized Spacelab module, which flew for the last time on this mission.

The mission might have ended a week early because of a problem with the Regenerative Carbon Dioxide Removal System, but ground-based engineers guided the crew through bypassing a “suspect valve” to enable them to stay on orbit.

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Atmospheric Science and Two Space Firsts

On this date, 15 years apart, two trailblazing (so to speak) female astronauts made historic space flights.


(Charlotte, North Carolina, photographed at night from STS-56. NASA image.)

Twenty years ago today — April 8, 1993 — the Space Shuttle Discovery launched from Kennedy Space Center carrying two science payloads. The STS-56 crew consisted of astronauts Kenneth D. Cameron, Stephen S. Oswald, C. Michael Foale, Kenneth D. Cockrell, and the first Hispanic woman to fly in space, Ellen Ochoa. The primary payload was the Atmospheric Laboratory for Applications and Science (ATLAS, in its second iteration, ATLAS-2), which was “designed to collect data on [the] relationship between [the] sun’s energy output and Earth’s middle atmosphere and how these factors affect ozone layer.” The crew also deployed and recovered the SPARTAN-201 free-flying science package, which examined the sun’s corona and the solar wind.

Also on this date, in 2008, Soyuz TMA-12 launched from the Baikonur Cosmodrome, carrying cosmonauts Sergei A Volokov and Oleg D. Kononenko, plus South Korean Yi So-Yeon, to the International Space Station. Yi was South Korea’s first astronaut, having been selected from 36,000 applicants. Volokov and Kononenko stayed aboard the ISS when Yi and the former ISS crew returned to Earth on April 19th.

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Pioneer 11: First Spacecraft to Saturn

Forty years ago today — April 5, 1973 — an Atlas Centaur rocket launched from Cape Canaveral carrying the Pioneer 11 space probe.


(Pioneer 11. NASA image.)

Pioneer 11 launched at 02:11 April 6th UTC, though it was still April 5th in Florida when it lifted off. It followed its sister ship, Pioneer 10, which had launched a little over a year before (on March 2, 1972).

Pioneer 11 was the first spacecraft to travel to Saturn, and returned close-up pictures of the ringed planet. On its way to Saturn, it used Jupiter’s gravity for course correction, and in so doing became the first spacecraft to photograph Jupiter’s polar region.

Pioneer 11 passed by Saturn on September 1, 1979, and then continued on toward the edge of the Solar System and the constellation Sagittarius. Contact with the spacecraft was lost in late 1995.

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Fifteen Years Apart: Apollo 6 and STS-6

Forty-five years ago today — April 4, 1968 — the final qualification flight of the Saturn V launch vehicle and the Apollo spacecraft launched from the Kennedy Space Center.


(Apollo 6 launch. NASA image.)

Apollo 6 consisted of a complete three-stage Saturn V, a Command and Service Module, and a “boilerplate” or “pathfinder” Lunar Module. The mission encountered several major problems:

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 hr 50 min after launch and was recovered in good condition.

Fifteen years later, on April 4, 1983, the Space Shuttle Challenger launched from the Kennedy Space Center on its first flight, mission STS-6. Astronauts Paul J. Weitz, Karol J. Bobko, Donald H. Peterson and Story F. Musgrave spent 5 days in space and deployed the first Tracking and Data Relay Satellite.

The STS-6 mission was not without its problems. The Inertial Upper Stage placed TDRS-1 in the wrong orbit, and later the satellite’s own thrusters were used to put it into the correct orbit (much like the service module’s thrusters being used on Apollo 6, and some recent spacecraft which have been recovered by judicious use of on-board propulsion). Nevertheless, the overall STS-6 mission was successful and featured the first spacewalk from a Shuttle.

Looking back at these two launches, it seems our space exploits have regressed instead of progressed. Given 10 years between Explorer 1 and Apollo 6, and 15 years between Apollo 6 and STS-6, and 30 years since then, you might think that we should have a colony on Mars by now. So this image of Challenger rolling out in the fog seems apt:


(STS-6 rollout to pad 39A, in the fog. NASA image.)

Here’s hoping we soon catch up to the future!

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The Mystery of Salyut 2

Forty years ago today — April 3, 1973 — the USSR launched Salyut 2 from the Baikonur Cosmodrome on a Proton K rocket.


(Line drawing of an Almaz space station. NASA image from Wikimedia Commons.)

According to the National Space Science Data Center, Salyut 2 “was designed for scientific research and testing of onboard systems and units” and failed “11 days after launch [due to] an unexplainable accident.”

The Wikipedia entry tells a different story: that Salyut 2 was one of the Soviet Union’s Almaz modules — a space station designed for military use, in answer to the USAF’s proposed Manned Orbiting Laboratory — and the first of the Almaz units to reach orbit. The station’s true purpose was hidden in plain sight by its being designated as a Salyut module.

Wikipedia also includes an explanation for the Almaz/Salyut’s failure:

Three days after the launch of Salyut 2, the Proton’s spent third stage exploded. Thirteen days into its mission, Salyut 2 began to depressurise, and its attitude control system malfunctioned. An inquiry into the failure initially determined that a fuel line had burst, burning a hole in the station. It was later discovered that a piece of debris from the third stage had collided with the station, causing the damage.

The source for the additional Salyut 2 information is this Russian Space Web page, which also notes that

Soon after the accident, official Soviet sources announced that the Salyut-2 had completed its operations “after a series of tests.” For years, official Soviet sources continued to claim that “during entire flight (of Salyut-2) reliable radio-contact with the station had been maintained … and all onboard systems and science equipment of the station had functioned normally.”

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