Universe Today

April 18, 2010December 24, 2015 by Nancy Atkinson

13 Things That Saved Apollo 13, Part 7: The Apollo 1 Fire

The Apollo 1 capsule after the fire. Credit: NASA

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Note: To celebrate the 40th anniversary of the Apollo 13 mission, for 13 days, Universe Today will feature “13 Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.

“Far better is it to dare mighty things, to win glorious triumphs, even though checkered by failure than to rank with those poor spirits who neither enjoy much nor suffer much, because they live in a gray twilight that knows not victory nor defeat.” – Theodore Roosevelt

It’s hard to chronicle any of the Apollo flights without mentioning the Apollo 1 fire. And while many believe the Apollo program perhaps wouldn’t have succeeded without that disaster, the sacrifice made by Gus Grissom, Ed White and Roger Chaffee definitely saved the crew of Apollo 13.

“Among the early space missions, I’ve always believed that the greatest courage was needed by their first crews,” said Apollo engineer Jerry Woodfill. “Whether it was Al Shepard, the Apollo 1 crew, or shuttle astronauts John Young or Bob Crippen, the most likely danger would be the first time any new space craft was launched into space. Flaws in design or manufacture could very well be fatal during maiden missions.”

The crew of Apollo 1: Gus Grissom, Ed White and Roger Chaffee. Credit: NASA

On January 27, 1967, during a test on the launch pad with the crew on board, tragedy struck when a flash fire started in the command module. With the pure oxygen environment inside the capsule, the fire quickly proved fatal for the crew before they or workers at the launch pad could get the hatch open. Although the ignition source of the fire was never conclusively identified, the astronauts’ deaths were attributed to a wide range of design and construction flaws in the early Apollo Command Module. The manned phase of the project was delayed for twenty months while these problems were fixed.

“To suggest the dire event of losing three brave astronauts contributing to Apollo 13’s rescue seems almost ludicrous,” said Woodfill, “but the evidence is striking. What Grissom, White and Chaffee contributed to the rescue of Apollo 13 makes them even more heroic than they were when they gave their lives so that men could go to the moon.”

The irony of the whole situation involves the hatch. Following Gus Grissom’s near fatal drowning when his Mercury capsule sank, the Apollo hatch had been redesigned to avoid the kind of unexpected actuation thought to have caused Grissom’s “Liberty Bell 7” to sink.

Gus Grissom and the Liberty Bell 7. Credit: NASA

“Unfortunately, it led to a hatch impossible to open before the Apollo 1 crew expired,” said Woodfill. “Nevertheless, circumstances used Gus, Ed, and Roger’s sacrifice to save other crews in route to the Moon.”

NASA fire-proofed all future Apollo vehicles with non-flammable materials, used a pad atmosphere of a nitrogen/oxygen mix, and coated of all electrical connections to avoid short-circuits.

“Every switch contact and wire was coated with a moisture proofing substance called conformal coating,” said Woodfill. “Were it not for fire-proofing the Apollo command and service modules, Apollo 13, likely, could not have survived reentry. The cold, damp reentry module interior faced extreme condensation of water vapor from the astronauts’ breath. Droplets of water formed behind the display panels.”

Diagram of the Apollo Command Module control panel. Credit: NASA History Office. Click for larger version.

Woodfill said when Apollo 13’s switches were activated for reentry, the interior would surely have burst into flame, were it not for the fireproofing. Condensed water droplets might have short-circuited panel switches, circuit breakers, and connector wiring.

Woodfill said America might never have landed a man on the Moon without Apollo 1. If a fire had occurred on the way to the Moon, it might have ended the will to land men there. “Imagine the horror of the world at such an event,” said Woodfill, “hearing the crew’s painful cries from deep space, ‘We’ve got a fire in the spacecraft.’”

Apollo 1 and the fireproofing of future Apollo spacecraft prevented such an event.

A favorite quote of many managers of the Apollo program, Woodfill said, is from President Theodore Roosevelt, the one posted at the top of this article.

“In a sense, the Apollo One mission was altogether different from Challenger, Columbia, and Apollo 13,” said Woodfill. “No one had dared such a mighty thing as to man the first Apollo spacecraft into orbit. And it, in this case, was fraught with suffering, failure and defeat, rather than a glorious triumph and victory.”

But later, it allowed for great triumph with the success of the Apollo program, and a defying of the odds of the Apollo 13 crew’s survival.

Tomorrow, Part 8: What the Explosion Didn’t Do

Additional articles from the “13 Things That Saved Apollo 13” series:

Introduction

Part 1: Timing

Part 2: The Hatch That Wouldn’t Close

Part 3: Charlie Duke’s Measles

Part 4: Using the LM for Propulsion

Part 5: Unexplained Shutdown of the Saturn V Center Engine

Part 6: Navigating by Earth’s Terminator

Part 7: The Apollo 1 Fire

Part 8: The Command Module Wasn’t Severed

Part 9: Position of the Tanks

Part 10: Duct Tape

Part 11: A Hollywood Movie

Part 12: Lunar Orbit Rendezvous

Part 13: The Mission Operations Team

Also:

Your Questions about Apollo 13 Answered by Jerry Woodfill (Part 1)

More Reader Questions about Apollo 13 Answered by Jerry Woodfill (part 2)

Final Round of Apollo 13 Questions Answered by Jerry Woodfill (part 3)

Never Before Published Images of Apollo 13’s Recovery

Listen to an interview of Jerry Woodfill on the 365 Days of Astronomy podcast.

April 17, 2010April 13, 2022 by Ken Kremer

WORF and Klingons occupy ISS

Japan Aerospace Exploration Agency (JAXA) astronaut Naoko Yamazaki, STS-131 mission specialist, works inside the Window Observational Research Facility (WORF) in the Destiny laboratory of the International Space Station while shuttle Discovery was still docked. WORF is a platform for cameras, multispectral scanners, and other sensors to capture science imagery of Earth imagery through Destiny's earth facing window. WORF is named after the Klingon character Worf beloved in the Star Trek Universe (top left). The WORF patch (lower left) is inscribed with Commander Worf’s name in Klingon script and was created by Tony Boatright. Credit: NASA images. WORF Patch: NASA/Tony Boatright. Mosaic: Ken Kremer

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WORF has finally joined the crew aboard the International Space Station (ISS). That’s great news for NASA as well as members and fans of the Klingon High Council who are delighted to occupy a prime location for exquisite surveillance of the Earth and Federation activities.

WORF is the acronym for the Window Observational Research Facility, a new science imaging platform on the ISS, which is named after the popular Klingon character from the “Star Trek: The Next Generation” science fiction television series. The surface panel on WORF sports a beautiful patch with a Klingon language inscription – spelling out the name WORF in Klingon script (see photo). Although seemingly innocent, Universe Today has learned that the Klingon High Council may have more sinister plans afoot for WORF involving future imperial undertakings.

WORF was permanently installed inside the US Destiny Lab module over the labs optical quality glass window by the STS 131 crew. Credit: NASA

The WORF science rack was one of the major new pieces of scientific equipment delivered to the ISS by the seven person crew of Space Shuttle Discovery during the highly successful STS 131 mission which blasted to space on April 5, 2010. WORF was packed into the ‘Leonardo’ resupply module which was the primary payload inside Discovery’s cavernous cargo bay.

WORF was designed by Earthlings to function as a photographic darkroom for precision remote space sensing of the Earth. As such, it’s also the only rack on the station that ISS astronauts and cosmonauts can actually physically float into and then maneuver equipment around to conduct their science research. “The working volume to accommodate instruments is about 23 cubic ft (0.8 cubic m)”, according to Dennis Toney of Boeing, Huntsville, Al, who I interviewed at the Kennedy Space Center during the STS 131 launch.

Panels, shelving and brackets inside WORF provide numerous attach points for digital cameras, multispectral and hyperspectral scanners, camcorders, sensors and other instruments to capture Earth imagery through Destiny’s nadir – Earth facing – window.
The experiments will focus on studies of atmospheric and climate properties, land and sea formations, geology, agriculture, ranching, environmental and coastal changes, and also be linked to public outreach and education efforts.

“EarthKAM is an example of a remotely controlled digital camera system that will be commanded to take pictures by middle school students across the US using web based tools”, Toney explained to me. The kids will learn how to work as real scientists. See WORF graphics provided to the author by Boeing/Denis Toney.

Graphics show WORF ‘darkroom’ science rack loaded with cameras and spectral payloads (left) and after closing with hatch (right) to exclude stray light from entering the payload volume. Crewmembers control the experiments loaded inside WORF using a laptop computer mounted on the front of the rack. NASA will use WORF for high resolution Earth observation experiments. Middle school students will be able to remotely control the EarthKAM digital camera payload inside WORF to take photos of the earth and learn how to work as real scientists. Graphics courtesy of Boeing/Dennis Toney were specially provided to the author for this story.

Astronauts installed the WORF darkroom inside the US Destiny Laboratory module and purposely “placed it in a bay directly over the labs 20 inch (508 mm) diameter observation window to provide direct access to the window from inside WORF”, said Toney.

“WORF provides the infrastructure to maximize the usability of the window. Up to 5 science payloads can be accommodated at once”, explained Toney. Numerous instrument connector ports and jacks for Ethernet computer connections, power, video and cooling are built directly into the rack to transmit the multispectral and high resolution experimental imaging data to the ground.

The Destiny window is the highest quality optical glass science window ever flown on any manned spacecraft. The window is constructed from 4 panes of optical quality glass pressed together that permit greater than 95% transmission across most of the visible spectrum and 90% transmission in the near infrared.

Jeff Williams, Expedition 13 Science Officer, at the U.S. Destiny Laboratory Science Window on the ISS. Williams recently served as the ISS Expedition 22 Commander.WORF was mounted on top of the Destiny window by the STS 131 crew.

The photographic and spectral gear – up to 350 mm aperture – mounted inside WORF can be remotely operated from Earth or by astronauts on board, who may also work in a hand held mode as required by the particular piece of equipment to maximize the scientific return.

An external shutter protects the window from micrometeoroid and orbital debris floating outside the station. The hinged cover can be manually opened and closed by the crew inside the cabin with a hand crank.

The “Leonardo’ Multi-purpose Logistics Module (MPLM) weighs over 27,000 pounds and is one of three such modules built by the Italian Space Agency. The module serves as a space moving van and was loaded with 16 science and storage racks – including WORF – holding over 17,000 pounds of science supplies and experiments, crew life support provisions, spare parts, a new astronaut sleep quarter and a minus 80 degree freezer to stow science samples collected by the resident ISS crew.

The Leonardo resupply module and Ken Kremer inside the Space Station Processing Facility at the Kennedy Space Center as the module was being prepared for launch aboard shuttle Discovery on the STS 131 mission. WORF science rack and over 17,000 pounds of science equipment and supplies were loaded inside Leonardo. Credit: Ken Kremer

After Discovery docked to the ISS, Leonardo was hoisted out of Discovery’s cargo bay and berthed to the station for the duration of the flight. The massive orbiting outpost is 98% complete – by habitable volume – and weighs in at 800,000 pounds and spans the length of an American football field.

Space Shuttle Discovery undocked from the ISS on Saturday morning (April 17) in preparation for a Monday April 19 landing at 8:51 AM. Credit: NASA

The STS 131 mission of Space Shuttle Discovery is nearing a close. Discovery undocked from the ISS early this morning at 8:52 AM and about 213 miles above earth and is set to land at KSC on Monday morning at 8:51 AM, weather permitting.

Authors Note: This paragraph is just for fun excepting Federation Counterintelligence agents. Unbeknownst to the crew members and NASA, top secret Klingon military surveillance technology was embedded deep within the WORF unit, according to a source who requested anonymity. Whilst the STS 131 crew was innocently hooking up umbilical line connections to the ISS electrical and computer systems, they unwittingly activated the Klingon Empires cloaking chip previously hidden inside WORF by time traveling Klingon spies dispatched by the High Council. The chip instantaneously began transmitting encoded data via sub space frequencies to eagerly waiting intelligence operatives working for the Klingon Chancellor. Stay tuned for more on WORF and the Klingon infiltration of the ISS.

Earlier STS 131 related articles by Ken Kremer:

Mother of Pearl Colored Clouds form above Kennedy after Discovery Blast Off

Spectacular Radar Failed Belly Flip (Video) and Docking links Discovery to ISS

Antenna Glitch hinders Data Flow from Inspection of Discovery

Discovery Dazzles with Two Dawns in One Day

Discovery Unveiled on Easter Sunday to the Heavens Above

Countdown Clock Ticking for Discovery Blast off on April 5

Soyuz Blasts off with Russian American Crew for Easter ISS arrival

Read more about the WORF Facility and the WORF Patch here:

NASA WORF Website

collectSpace.com Forum discussion on WORF patch

Dennis Toney (Boeing) and Ken Kremer discuss the science goals of the WORF facility at the Kennedy Space Center Press Site during the STS 131 launch of shuttle Discovery on April 5, 2010. Discovery delivered WORF to the ISS. Credit: Ken Kremer

April 17, 2010April 26, 2016 by Jean Tate

Hubble at 8: So Many Discoveries, So Quickly

Planetary Nebula M2-9 (Credit: Bruce Balick (University of Washington), Vincent Icke (Leiden University, The Netherlands), Garrelt Mellema (Stockholm University), and NASA)

Note: To celebrate the 20th anniversary of the Hubble Space Telescope, for ten days, Universe Today will feature highlights from two year slices of the life of the Hubble, focusing on its achievements as an astronomical observatory. Today’s article looks at the period April 1996 to April 1998.

The ability of the Hubble Space Telescope to be serviced by astronauts, using a space shuttle as a platform, is one of its design features. This proved its worth very early, with the first servicing mission installing COSTAR. The second such mission – a ten day effort with Discovery as the workhorse – took place in February 1997; two new instruments were installed (and two removed), the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Space Telescope Imaging Spectrograph (STIS), and many other, smaller, upgrades and repairs made.

Yesterday’s article featured the Pillars of Creation; today’s captures the beauty of a star’s death.
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STScI's home, John Hopkins University, Homewood Campus (Credit: John Hopkins Univerity)

How does the Hubble work? Who runs it? The Space Telescope Science Institute (STScI) is responsible for the scientific operation of Hubble as an international observatory; it has a combined staff of approximately 500, of whom approximately 100 are PhDs. Among the prime tasks of the STScI are the selection of the Hubble observing proposals, their execution, the scientific monitoring of the telescope and its instruments and the archiving and distribution of the Hubble observations.

The Space Telescope-European Coordinating Facility (ST-ECF) offers support for the preparation of Hubble observing proposals and the scientific analysis of observations. It also operates the Hubble Science Archive, which makes data available to the astronomical community via the Internet.

With the exception of observations like the Hubble Deep Field – which are available for immediate release – the data from Hubble observations are the exclusive property of the observers for one year, after which all scientific data are made available to anyone and everyone, via the internet. And guess what? Thousands of papers have been published, using such freely available data!

Asteroid Trail Crosses Galaxy NGC 4548 (Credit: R. Evans and K. Stapelfeldt (JPL) and NASA)

One example of the tremendous value of the Hubble archive is all the asteroids it inadvertently images; because of the Hubble’s sensitivity, motion, and resolution, the orbits of many of these can be determined from just the serendipitous images (discoveries made by ground-based telescopes usually require follow-up images days apart). And yes, many papers have been written, based on these images, “Asteroid Trails in Hubble Space Telescope” for example.

Sometimes something happens in the sky and you want to point powerful telescopes at it, quickly, before it disappears. By far the most interesting yet fleeting ‘something’ is gamma-ray bursts (GRBs). Although known for decades, none had been seen in any other electromagnetic waveband … until February 28, 1997. Right after its servicing mission, Hubble caught the afterglow of GRB 970228, located in very distant galaxy. A milestone in astronomy.

Volcanoes, active ones, were discovered on Io, by accident, in 1979, as volcanic plumes rising above the limb. Who could have imagined that such plumes would be imaged not twenty years later, from low-Earth orbit, with Jupiter as the backdrop?

In 1920 Betelgeuse’s diameter was estimated, using a 6 meter interferometer mounted on the front of the 100-inch Mount Wilson telescope. In 1996, the Hubble made a direct observation of Betelgeuse, resolving it; only the second star to have ever been seen as anything but a point of light (what was the first?).

Antennae Galaxies (Credit: Brad Whitmore (STScI) and NASA)

The Antennae galaxies, NGC 4038/NGC 4039, are not only highly photogenic (how many amateurs count their snaps of these among their most prized?), but great natural laboratories for studying galaxy collisions, star formation, etc. Hubble’s 1997 images provided the basis for hundreds of papers.

Tomorrow: 1998 and 1999.

Previous articles:
Hubble’s 20 Years: Now We Are Six
Hubble’s 20 Years: Time for 20/20 Vision
Hubble: It Was Twenty Years Ago Today

Sources: HubbleSite, European Homepage for the NASA/ESA Hubble Space Telescope, The SAO/NASA Astrophysics Data System

April 17, 2010December 24, 2015 by Steve Nerlich

Astronomy Without A Telescope – One Potato, Two Potato

Sometimes it’s good to take a break from mind-stretching cosmology models, quantum entanglements or events at 10^-23 seconds after the big bang and get back to some astronomy basics. For example, the vexing issue of the potato radius.

At the recent 2010 Australian Space Science Conference, it was proposed by Lineweaver and Norman that all naturally occurring objects in the universe adopt one of five basic shapes depending on their size, mass and dynamics. Small and low mass objects can be considered Dust – being irregular shapes governed primarily by electromagnetic forces.

Next up are Potatoes, being objects where accretion by gravity begins to have some effect, though not as much as in the more massive Spheres – which, to quote the International Astronomical Union’s second law of planets, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape.

Objects of the scale of molecular dust clouds will collapse down into Disks where the sheer volume of accreting material means that much of it can only rotate in a holding pattern around and towards the centre of mass. Such objects may evolve into a star with orbiting planets (or not), but the initial disk structure seems to be a mandatory step in the formation of objects at this scale.

At the galactic scale you may still have disk structures, such as a spiral galaxy, but usually such large scale structures are too diffuse to form accretion disks and instead cluster in Halos – of which the central bulge of a spiral galaxy is one example. Other examples are globular clusters, elliptical galaxies and even galactic clusters.

The proposed five major forms that accumulated matter adopts in our universe. Credit: Lineweaver and Norman.

The authors then investigated the potato radius, or R_pot, to identify the transition point from Potato to Sphere, which would also represent the transition point from small celestial object to dwarf planet. Two key issues emerged in their analysis.

Firstly, it is not necessary to assume a surface gravity of a magnitude necessary to generate hydrostatic equilibrium. For example, on Earth such rock crushing forces only act at 10 kilometres or more below the surface – or to look at it another way you can have a mountain on Earth the size of Everest (9 kilometres), but anything higher will begin to collapse back towards the planet’s roughly spheroid shape. So, there is an acceptable margin where a sphere can still be considered a sphere even if it does not demonstrate complete hydrostatic equilibrium across its entire structure.

Secondly, the differential strength of molecular bonds affects the yield strength of a particular material (i.e. its resistance to gravitational collapse).

On this basis, the authors conclude that R_pot for rocky objects is 300 kilometres. However, R_pot for icy objects is only 200 kilometres, due to their weaker yield strength, meaning they more easily conform to a spheroidal shape with less self-gravity.

Since Ceres is the only asteroid with a radius that is greater than R_pot for rocky objects we should not expect any more dwarf planets to be identified in the asteroid belt. But applying the 200 kilometre R_pot for icy bodies, means there may be a whole bunch of trans-Neptunian objects out there that are ready to take on the title.

April 17, 2010December 24, 2015 by Nancy Atkinson

Never Before Published Images of Apollo 13 Recovery

Jim Lovell talks with USS Iwo Jima crew after the Apollo 13 capsule was recovered. Image courtesy of Robert Gillette.

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Today marks the 40th anniversary of the successful return and recovery of the Apollo 13 spacecraft and crew, which has been called the the most satisfying splashdown in the history of human spaceflight. The images here of the safe return of the Apollo 13 astronauts have never been published before, and were sent to Universe Today by reporter Robert Gillette.

“Once in a while, we manage to be in the right place at the right time with a camera in hand,” Gillette wrote Universe Today. “I happened to be on the USS Iwo Jima as a young science reporter (for the-then San Francisco Examiner) in April 1970. By the time I made it back to shore to develop the film it no longer had news value. Maybe 40 years later they have historic value, at least for the emotion written in the faces of Lovell, Swigert and Haise. So I dug the old Kodachromes out and had them digitized.”

Regarding the photo above, Gillette said he overheard Apollo 13 Commander Jim Lovell tell the Admiral of the Iwo Jima, “Thank God for Grumman,” referring to the Grumman-built lunar lander that served as the lifeboat for Lovell, Fred Haise and Jack Swigert following the explosion that crippled the Command and Service Module. Gillette has determined the admiral to Lovell’s left is Rear Admiral Donald C. Davis, Commanding Officer of Task Force 130, the Pacific Recovery Force for the Manned Spacecraft Missions.

See more images from Gillette, below.

Rescue helicopter prepares to touch down on deck of USS Iwo Jima with Apollo 13 astronauts aboard, April 17, 1970. Image courtesy Robert Gillette.

Lovell and Swigert emerge from rescue helicopter, April 17, 1970. Image courtesy Robert Gillette.

Swigert and Haise emerge from rescue helicopter,steppind on deck of the Iwo Jima. Image courtesy Robert Gillette. — Jack Swigert and Fred Haise emerge from rescue helicopter,stepping on deck of the Iwo Jima. Image courtesy Robert Gillette.

Haise and Lovell emerge on deck for helicopter ride to American Samoa. Image courtesy Robert Gillette.

Swigert strides on deck moments later for helicopter ride to American Samoa. Image courtesy Robert Gillette.

Our thanks to Robert Gillette for sending us these unique images on this anniversary of the historic return of Apollo 13. For more unique information on Apollo, see our ongoing series, “13 Things That Saved Apollo 13,” our discussion with Apollo engineer Jerry Woodfill which highlights various turning points of the mission.

April 16, 2010April 26, 2016 by Jean Tate

Hubble’s 20 Years: Now We Are Six

After the famous Apollo 8 “Earthrise” image, comet Shoemaker-Levy 9’s impact with Jupiter, in July 1994, strikes us as the most stark reminder of the fragility of our home. And the Hubble gave us the clearest pictures of just how destructive that collision was; those dark blotches are bigger than the Earth.

Equally memorable, from Hubble’s early childhood years – ages five and six – is the “Pillars of Creation” image.
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Much of the Hubble’s time in the first few years was devoted to the Hubble Space Telescope Key Projects, two of which I mentioned yesterday, “on the Extragalactic Distance Scale”, and the “Quasar Absorption Line” Key Project. There is a third, the Medium-Deep Survey (MDS), lead by Richard Griffiths, who is now at Carnegie Mellon University. Here’s a nice bit of trivia: astronomers spend an inordinate, a humongous amount of time doing surveys; they even build entire observatories devoted exclusively to them (think Sloan Digital Sky Survey, of Galaxy Zoo fame)! And here’s a question for you: why? Why are surveys soooo important to astronomers?

Hubble images of distant spiral galaxies (Credit: NASA, Richard Griffiths/JHU, Medium Deep Survey Team)

Anyway, MDS is interesting for another reason too; it’s a “parallel mode” project … while the Hubble is pointed at its main target, a nearby field is also observed, using WF/PC or the Faint Object Camera (or, later, WFPC2); two results for the price of one! However, perhaps more than any other observations, the MDS ones before the Hubble had its vision fixed (see yesterday’s article) suffered from the mis-figuring of the primary mirror. And it’s a tribute to the ingenuity and perseverance of Griffiths and his colleages that they were, eventually, to wring so much good science from the data (you guessed it, hundreds and hundreds of papers).

Uranus, rings, and moons (Credit: Kenneth Seidelmann, U.S. Naval Observatory, and NASA)

Jupiter wasn’t the only solar system object of interest to Hubble; Uranus, its rings and inner moons captured on film (well, CCD); the first surface features on Pluto were snapped; Saturn’s Aurorae imaged; the Galilean moons of Jupiter mapped; etc, etc, etc.

Credit: J. Bahcall, Institute for Advance Study, Princeton, F. Paresce, STScI & ESA, and NASA

My own favorite Hubble recollection from these two years is (another!) paper by John Bahcall, “M dwarfs, microlensing, and the mass budget of the Galaxy“, which basically proved that the Milky Way’s halo is composed principally of non-baryonic dark matter. I remember reading it and thinking, “nah, that can’t be right, you guys can’t conclude that from that data!”, but the more I gnawed at it, the more it struck me just how simple, yet profound, this work was (pay attention you fans of Universe Puzzle, there’s a clue to a future puzzle here).

Hubble Deep Field (R.E. Williams/STScI/NASA; Werry/Blanton/Hogg (NYU), Lupton (Princeton))

Finally, towards the end of the time I’m covering in this article, Hubble took the famous Hubble Deep Field. The version posted here you may not have seen before, because it uses a different color transform, by Robert Lupton (more images using this technique here).

Tomorrow: 1996 and 1997.

Previous articles:
Hubble’s 20 Years: Time for 20/20 Vision
Hubble: It Was Twenty Years Ago Today

Sources: HubbleSite, European Homepage for the NASA/ESA Hubble Space Telescope, The SAO/NASA Astrophysics Data System

April 16, 2010April 26, 2016 by Nancy Atkinson

Meteorite Recovered from April 14 Fireball

Christopher and Evan Boudreaux hold the first recovered meteorite from the April 14, 2010 Wisconsin fireball. The first stone was recovered 22 hours after the fall. Credit: Terry Boudreax, shared by Michael Johnson from Rocks From Space

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Via the Astro Bob and Rocks From Space websites comes news that the first meteorite has been recovered from the spectacular fireball that was seen over seven states on April 14, 2010. Brothers Christopher and Evan Boudreaux from southern Wisconsin located a piece of what was likely a meter-wide space rock, according to NASA’ Near Earth Object office. Astro Bob said that pieces of meteorite from Wednesday night’s amazing fireball appear to have fallen over the Livingston, Wisconson area between Platteville and Avoca. If you’re in that area, maybe you’ll have time to do a little meteorite hunting this weekend. But always get permission before going on any private property.

The image above, as well as a close-up of the meteorite, below, are courtesy of Michael Johnson, who hosts the Rocks From Space website Johnson said that according to Mike Farmer, a professional meteorite hunter, the meteorite appears to be an H chondrite.

The first recovered meteorite from the April 14, 2010 fireball. Photo by Terry Boudreaux (c) 2010, via Rocks From Space, used by permission.

Astro Bob indicated there is a meteorite for sale on e-Bay claiming to be from the April 14 fall, but it is not, so beware.

According to NASA’s NEO office, data collected by scientists at NASA’s Marshall’s Space Flight Center in Huntsville, Alabama indicate the parent body of the fireball was not associated with the Gamma Virginids meteor shower, which was taking place at the time the fireball entered the atmosphere. Instead, the small space rock more than likely originated from somewhere in the asteroid belt.

The head of the NEO office, Don Yeomans, said that when the fireball disintegrated high in the atmosphere, it released energy equivalent to the detonation of approximately 20 tons of TNT.

“Knowing the size of this small asteroid helps us determine the frequency of such occurrences,” Yeomans said. “Asteroids this size are expected to enter Earth’s atmosphere about once a month.”

Here’s a mash-up of webcams, dashboard-cams etc. that captured the fireball.

Sources: Astro Bob, Rocks From Space, NASA’s NEO office, JPL

April 16, 2010April 26, 2016 by Nancy Atkinson

13 Things That Saved Apollo 13, Part 6: Navigating By Earth’s Terminator

Earth's Terminator, showing darkness and daylight, July 1969, as seen from NASA's Apollo 11 Spacecraft.

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Note: To celebrate the 40th anniversary of the Apollo 13 mission, for 13 days, Universe Today will feature “13 Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.

The rupture and explosion of Apollo 13’s oxygen tank crippled the spacecraft, endangering the lives of the crew and making a Moon landing not an option. But more problems arose as the perilous flight progressed. Keeping the spacecraft on the right trajectory was a huge challenge for Mission Control, and especially for the crew. Normally, the ship’s computers allowed for much of the navigation, but due to the loss of the Service Module as an electrical power source, even backup navigation and targeting functions were unavailable. The Lander’s limited battery power required the shutting down of its guidance computer. The astronauts also needed to use an on-board sextant to confirm their location by sighting-in the stars, similar to how ancient sailors navigated. “There are thirty-seven stars – and one is the sun,” said Apollo engineer Jerry Woodfill, “that provided an accurate way of aligning the spacecraft’s computer platform to allow the astronauts to steer their way through the heavens.”

But the explosion of the tank had enshrouded the Apollo 13 spacecraft with debris. Commander Jim Lovell and his crew couldn’t discern the stars from the particles that glimmered in the sunlight. “The situation was, without the ability to see the stars, you couldn’t navigate,” Woodfill said.

But NASA had a backup navigation plan, thanks to an insightful NASA contractor employee. This novel way of navigating had only been tried once before in space. And coincidentally, the astronaut who used it was Jim Lovell, during his previous flight — Apollo 8 — which orbited the Moon in December of 1968.

An employee of TRW – which was the contractor for many of the navigational systems and procedures for NASA — thought of an unusual backup navigation plan one day. “This fellow is a friend and neighbor of mine,” said Woodfill, “and by his account of the story to me, he said that a thought came to him one day about Apollo astronauts using stars to navigate. What if the stars couldn’t be seen? Now, that was highly unlikely, as there are no clouds, fog, or smoke to conceal stars from viewing by astronauts. But, nevertheless, the thought simply wouldn’t cease. Soon a follow-up idea came to mind. Why not use the Earth’s terminator?”

The nominal flight plan for a mission to the Moon. Credit: Apollo 13 report.

The terminator is the line which delineates between night and day on Earth; where the Sun is shining and where it is dark.

Woodfill’s friend figured out the geometry and wrote a computer program to validate the idea. He submitted the proposal to the navigation board, which approved the technique so that it was entered into the computers in the Mission Control Center.

Through unusual, and what could be called happenstance circumstances, Lovell experimented with the backup plan during Apollo 8.

Lovell served as navigator for the first manned mission to orbit the Moon. He made a star sighting in preparation for the return to Earth, and entered the coordinates into the Apollo spacecraft’s primitive computer using the “DSKY” (display and keyboard). Instead of pressing the ENTR (enter) key, he inadvertently pressed the adjacent CLR (clear) key erasing the entire navigational alignment.

“Lovell consulted with Mission Control whether to repeat the sextant star sighting,” Woodfill said, “and someone realized this would be an opportunity to test the backup ‘seat of the pants’ means of navigating using the Earth’s terminator. And it worked! But then everyone forgot about it, until…guess when?”

Apollo 13's view of the Moon. Credit: NASA

Initially, the Apollo 13 crew was able to use the Sun as a “marker” to help in guiding the spacecraft to confirm they were on the right path, and were able to fire the LM engines for course corrections using the transferred guidance platform from the Command Module.

But as Apollo 13 headed back to Earth, the Reentry (RETRO) and Guidance, Navigation and Control (GNC) officers looking at the trajectory analysis noticed the spacecraft was coming in too “shallow,” that is, Apollo 13 was headed to skip off the atmosphere and out into space forever. Something seemed to be “blowing” the spacecraft off course. Later, it was discovered that cooling vapor from the lander was responsible. Since no lander had been present for previous missions on a return trip from the Moon, such a mysterious “wind” had never been encountered prior to Earth re-entry.

Another burn was needed, but no help from the guidance system would be available, as powering the lander’s guidance system, its gyros, the computer, etc. would use too much electrical power.

Here’s where the backup navigation approach that Lovell experimented with on Apollo 8 came to the rescue.

“If a ‘dead-reckoning’ approach could be used, no electricity would be needed,” said Woodfill. “Simply point the vehicle correctly, start the engine and stop it based on Mission Control’s prescribed time for its operation.” Lovell eyed up the Earth’s terminator line and controlled the “yaw” of the spacecraft, Haise controlled the “pitch” and Swigert timed it with his accurate Omega Speedmaster watch.

Graphics from the Apollo 13 report on using Earth's terminator for navigation.

The Navigation report for Apollo 13 describes it this way:

“The cusps of the Earth terminator were placed on the Y axis of the COAS. The illuminated part of the Earth was placed at the top of the reticle. Pitch attitude was achieved by placing the Sun in the upper portion of the AOT (see below). This procedure aimed the LM +Z axis at the Earth and aligned the LM +X axis retrograde along the local horizontal. An AGS body axis alignment was performed, followed by transitioning the AGS to the automatic attitude hold mode. A maneuver to burn attitude was performed, followed by another body axis alignment.”

Navigation graphics from the Apollo 13 report.

Woodfill said he enjoyed Hollywood’s re-enactment of the procedure in the “Apollo 13” movie. Though the spacecraft gyrations about the heavens are wholly exaggerated, the scene where Tom Hanks, Bill Paxton, and Kevin Bacon set-up and execute the terminator burn is generally accurate.

Suffice to say, the procedure worked for Hollywood dramatics, but more importantly, it worked to save the lives of Lovell, Haise and Swigert.

Tomorrow, Part 6: Fire

Other articles from the “13 Things That Saved Apollo 13” series:

Introduction

Part 1: Timing

Part 2: The Hatch That Wouldn’t Close

Part 3: Charlie Duke’s Measles

Part 4: Using the LM for Propulsion

Part 5: Unexplained Shutdown of the Saturn V Center Engine

Listen to an interview of Jerry Woodfill on the 365 Days of Astronomy podcast.

April 15, 2010April 26, 2016 by Jean Tate

Could An Amateur Astronomer Snap a Picture of an Exoplanet?

HR8799b, c, and d (Credit: NASA/JPL-Caltech/Palomar Observatory)

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Using their backyard telescope, today? No; however, this image of three exoplanets required just 1.5 meters (diameter; 60 inches) of a telescope mirror, not vastly larger than the biggest backyard ‘scope.

These particular exoplanets orbit the star HR 8799, and have been imaged directly before, by one of the 10-meter (33-foot) Keck telescopes and the 8.0-meter (26-foot) Gemini North Observatory, both on Mauna Kea in Hawaii; they are among the first to be so imaged, as reported by Universe Today in November 2008 First Image of Another Multi-Planet Solar System.

So how did Gene Serabyn and colleagues manage the trick of taking the image above, using just a 1.5-meter-diameter (4.9-foot) portion of the famous Palomar 200-inch (5.1 meter) Hale telescope’s mirror?

Infrared observations of a multi-exoplanet star system HR 8799 (Keck Observatory)

They did it by working in the near infrared, and by combining two techniques – adaptive optics and a coronagraph – to minimize the glare from the star and reveal the dim glow of the much fainter planets.

“Our technique could be used on larger ground-based telescopes to image planets that are much closer to their stars, or it could be used on small space telescopes to find possible Earth-like worlds near bright stars,” said Gene Serabyn, who is an astrophysicist at JPL and visiting associate in physics at the California Institute of Technology in Pasadena.

The three planets, called HR8799b, c and d, are thought to be gas giants similar to Jupiter, but more massive. They orbit their host star at roughly 24, 38 and 68 times the distance between our Earth and the Sun, respectively (Jupiter resides at about five times the Earth-Sun distance). It’s possible that rocky worlds like Earth circle closer to the planets’ homestar, but with current technology, they would be impossible to see under the star’s glare.

The star HR 8799 is a bit more massive than our sun, and much younger, at about 60 million years, compared to our sun’s approximately 4.6 billion years. It is 120 light-years away in the constellation Pegasus. This star’s planetary system is still active, with bodies crashing together and kicking up dust, as recently detected by NASA’s Spitzer Space Telescope. Like a fresh-baked pie out of the oven, the planets are still warm from their formation and emit enough infrared radiation for telescopes to detect.

To take a picture of HR 8799’s planets, Serabyn and his colleagues first used a method called adaptive optics to reduce the amount of atmospheric blurring, or to take away the “twinkle” of the star. For these observations, technique was optimized by using only a small fraction of the telescope was used. Once the twinkle was removed, the light from the star itself was blocked using the team’s coronograph, an instrument that selectively masks out the star. A novel “vortex coronagraph,” invented by team member Dimitri Mawet of JPL, was used for this step. The final result was an image showing the light of three planets.

While adaptive optics is in use on only a few amateurs’ telescopes (and a relatively simple kind at that), the technology will likely become widely available to amateurs in the next few years. However, vortex coronagraphs may take a bit longer.

“The trick is to suppress the starlight without suppressing the planet light,” said Serabyn.

The technique can be used to image the space lying just a few arcseconds from a star. This is as close to the star as that achieved by Gemini and Keck – telescopes that are about five and seven times larger, respectively.

Keeping telescopes small is critical for space missions. “This is the kind of technology that could let us image other Earths,” said Wesley Traub, the chief scientist for NASA’s Exoplanet Exploration Program at JPL. “We are on our way toward getting a picture of another pale blue dot in space.”

Sources: JPL, Nature, Astrophysics Journal (preprint is arXiv:0912.2287)

April 15, 2010December 24, 2015 by Jean Tate

Hubble’s 20 Years: Time for 20/20 Vision

“And we have liftoff, liftoff of the Space Shuttle Endeavor, on an ambitious mission to service the Hubble Space Telescope”

Without a doubt, Servicing Mission 1 in early December 1993 was the high point of the Hubble Space Telescope’s third and fourth years in space.

For starters, it successfully replaced the high speed photometer instrument with COSTAR (Corrective Optics Space Telescope Axial Replacement), which, as its name implies, corrected for the mis-figured primary mirror and so permitted the three instruments not replaced to make the high quality images intended (they were the Faint Object Camera, the Faint Object Spectrograph, and the Goddard High Resolution Spectrograph).

It also replaced the WF/PC (Wide Field Planetary Camera) with an upgraded WF/PC (called WFPC2), and made several other repairs and replacements which considerably improved the Hubble’s performance and robustness.
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Well before the Hubble was launched much of its observing time was pre-allocated, especially to two Hubble Key Projects, “on the Extragalactic Distance Scale”, and the “Quasar Absorption Line” Key Project. The former is well-known (and I’ll cover it in a later Hubble 20th birthday article); the latter hardly known at all outside the astrophysics community. It was the brainchild of the remarkable John Bahcall, and much of the Hubble’s time in its first four years was devoted to it. There are 13 main papers on its results, with hundreds more based on them. In a word, this project revolutionized our understanding of the space between galaxies and galaxy clusters, all the way from just beyond the Milky Way to billions of light-years distant.

The lucky 16 amateurs (Credit: NASA/STScI)

It wasn’t only professional astronomers who used the Hubble in these two years; 16 amateurs did too! Do you know what they found? If you had the chance, what would you use the Hubble to observe?

Comet Shoemaker-Levy 9 (Credit: Dr H.A. Weaver, T.E. Smith; STScI/NASA)

Perhaps the most captivating images the Hubble took in these two years are the ones of Comet Shoemaker-Levy 9 on its way to a collision with Jupiter (I’ll cover the collision itself tomorrow). Do you remember, back then, that asteroid and comet threats to life on Earth just became a whole lot more believable?

eta Carinae (Credit: J.Hester/Arizona State University/NASA)

3C273's jet (Credit: R.C. Thomson&C.D. Mackay, IoA, Cambridge, UK; A.E. Wright, ATNF)

Hubble sent back images of many more objects in these two years, including a much better one of eta Carinae (compare this one with the one in yesterday’s article) and the optical jet of the iconic quasar 3C273.

Tomorrow: 1994 and 1995.

Previous article:
Hubble: It Was Twenty Years Ago Today

Sources: HubbleSite, European Homepage for the NASA/ESA Hubble Space Telescope, The SAO/NASA Astrophysics Data System