Sinking the Bismarck

An evening pause: For Memorial Day, let’s have some history recounting one of the most important Atlantic naval battles of World War II, which took place 82 years ago this weekend. If the Bismarck had been successful in getting out into the Atlantic to attack convoys, Great Britain could very well have been starved into submission.

Hat tip Mike Nelson, who adds, “The ravages of WWII have faded from memory but we should never forget. Too many paid the price for the freedoms we so blithely take for granted.”

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NASA now demolishing the obsolete mobile launch platform used during Apollo

The second of three mobile launch platforms that were used during the Apollo program to transport the Saturn-5 rocket to its launchpad but are all obsolete and no longer in use is finally being demolished for salvage.

The first has already been scrapped, while the third is still in use for “servicing the crawlerway between SLS launches.”

NASA has been storing the platform in the Vehicle Assembly Building, but there was no longer room there, with Boeing taking over more space for assembling SLS core stages. The platform itself was deemed unsafe for display at any museum, with the cost of making it safe too high.

Better to salvage it than have it sit in the way of future space operations. After all, when you get down to it, it is simply some metal and hardware. The history was accomplished by the humans who built it, and who would be appalled if later generations used their work as a club to prevent new achievements in space.

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The only rocket stage recovered during the 1960s space race returns to Florida

A section of the Gemini 5 Titan rocket first stage that was recovered by chance right after its launch on August 21, 1965 has now been moved from storage in Alabama to be put on display at the Cape Canaveral Space Force Museum.

The artifact, which encompasses the upper portion of the Titan II rocket’s first stage, flew with the vehicle from Launch Complex 19 at Cape Kennedy (today Cape Canaveral) in Florida for the first two and a half minutes of flight, reaching about 50 miles high (80 kilometers) before its two-nozzle engine exhausted its propellant supply. Unlike most rockets, which jettison their first stage before firing their second stage engine(s), Gemini-Titan “fired in the hole,” igniting the upper stage before separating from the first.

The Titan II first stage then plunged back to Earth, impacting the Atlantic Ocean off the coast of Bermuda with no plans for its recovery. It was only by happenstance that a U.S. Air Force plane spotted the segment floating in the water, which led to a U.S. Navy destroyer, the U.S.S. Du Pont, hauling it out of the ocean and back to shore.

Whether the surviving segment, which housed the booster’s oxidizer tank, tore apart from its fuel tank and engine section during the tumble back to Earth or on contact with the ocean is unknown. The lower section of the stage presumably sank to the seafloor.

Until the shuttle started flying in 1981, this booster section was the only first stage recovered from any American rocket launch. The rocket itself had lifted Gordon Cooper and Pete Conrad into orbit, where they spent a then record eight days, proving humans could survive in space long enough to get to and from the Moon.

Lots of pictures at the link. More pictures here.

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Alabama roadside rest stop about to lose its Saturn-1B rocket

Due to decay and rust, an Alabama roadside welcome center is about to lose the Saturn-1B rocket that has greeted visitors for the past 44 years.

The Welcome Center opened in 1977. In 1979, the U.S. Space and Rocket Center donated the Saturn 1B rocket, 168 feet high and 22 feet in diameter, to stand as a symbol of Huntsville’s role in the space program. The rocket was painted in 2006 and more maintenance was done starting in 2014, but it has steadily deteriorated since then.

“It was starting to fall apart,” [said Lee Sentell, director of the Alabama Tourism Department.] “We’ve gotten complaints for years about it.”

The cost to refurbish it appears to be too high. Maybe Sentell can get NASA to donate an SLS rocket for display, since it is very possible that several of those will become available at some point in the future when SpaceX’s much more efficient and cheaper Starship/Superheavy begins flying.

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The same region on Ganymede, as seen by Voyager-1 in 1979 and Juno in 2021

Ganymede compared between Voyager-1 and Juno
Click for full image.

When the Jupiter orbiter Juno did a close pass of the moon Ganymede on June 7, 2021, it took four pictures, covering regions mostly photographed for the first time by Voyager-1 in its close fly-by in 1979.

Scientists have now published the data from this new fly-by. Though Juno’s higher resolution pictures revealed many new details when compared with the Voyager-1 images from four decades earlier, the scientists found no changes. The comparison image, figure 2 of their paper, is to the right, reduced and sharpened to post here.

A flicker comparison between the registered JunoCam and Voyager reprojected mosaics revealed no apparent new impact features. Given the high albedo of fresh craters on Ganymede, with high albedo ejecta deposits two or three times the diameter of the craters themselves, we argue that new craters as small as 250 m diameter would be detectable in images at these 1 km per pixel scales. Extrapolating Ganymede cratering rates from Zahnle et al. (2003) below 1 km, the probability of JunoCam observing a new crater over 12.2 million km2 in 42 years is 1 in 1500, consistent with none being observed.

In other words, at these resolutions finding no new impacts is not a surprise.

Of the new features detected, the Juno images could see more details in the bright rays emanating from the crater Tros (in the lower center of both images), and thus found “…terrain boundaries previously mapped as ‘undivided’ or as ‘approximate’, several large craters, and 12 paterae newly identified in this region.”

Paterae resemble craters but are thought to be a some form of volcanic caldera. Their geological origin however is not yet completely understood.

The paper’s conclusion is actually the most exciting:

The insight gained from this handful of images makes it likely in our opinion that new observations from the upcoming JUICE and Europa Clipper missions will revolutionize our understanding of Ganymede.

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Could the Apollo 11 lunar module still be orbiting the Moon?

According to one researcher, at least two of the Apollo lunar modules that took astronauts up and down from the Moon could still be in lunar orbit, though their location is presently unknown.

His paper outlining the possible survival of the Apollo 11 LM Eagle can be found here. From his abstract:

The Apollo 11 “Eagle” Lunar Module ascent stage was abandoned in lunar orbit after the historic landing in 1969. Its fate is unknown. Numerical analysis described here provides evidence that this object might have remained in lunar orbit to the present day. The simulations show a periodic variation in eccentricity of the orbit, correlated to the selenographic longitude of the apsidal line. The rate of apsidal precession is correlated to eccentricity. These two factors appear to interact to stabilize the orbit over the long term.

More details here.

Hat tip to reader Mike Nelson, who sent me this story today. I am certain I reported it previously, but searching on Behind the Black failed to find it, so I decided to post again. As the researcher concludes:

Wouldn’t it be amazing if we could find this amazing little vessel and bring her back to Earth!!!!

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Remembering Apollo 17, fifty years after the last manned mission to the Moon

LRO oblique view of Apollo 17 landing site
Click for full image.

Link here.

The article comes from the Lunar Reconnaissance Orbiter (LRO) science team, and includes a number of LRO photos of the landing site, including the oblique annotated image to the right, reduced to post here. As the article notes:

The Apollo 17 crew was the last of an era in human space exploration and the last to set foot on the Moon. Fifty years later, the landing sites, hardware, and footsteps remain delicately preserved on the lunar surface. Join the LRO team as we commemorate their inspiring achievements with additional images, research, maps, interactive sites, and a dedicated video. LRO continues to image the Apollo sites whenever possible, under multiple lighting conditions, and combine these images into interactive sites, like the Apollo 17 Temporal Traverse. The Lunar QuickMap 3D tool can be used to preview the Apollo landing sites and search for LROC images of the areas. For downloadable maps of the Taurus-Littrow Valley, visit the Map Sheets section on our downloads page here. Finally, the Apollo 17 fiftieth anniversary video below presents highlights of the mission with landing site views reconstructed using LROC images and topography.

I have embedded that video below. It does a marvelous job summarizing this mission, which in many ways remains the most daring human exploration mission since Columbus dared cross an ocean in a tiny ship only slightly larger than many lifeboats.
» Read more

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Last 747 rolls off assembly line

Boeing earlier this week completed assembly of its very last 747 airplane, the 1,574th such plane built in the past half century.

Still in its iridescent green protective coating, the giant aircraft was towed out of the widebody aircraft factory in a low-key exercise without any fanfare. Once the 747 has been cleared, it will be flown to another Boeing facility where it will be painted in the Atlas Air livery in anticipation of final delivery to the customer next year.

The 747 was born out of a failed bid by Boeing to market a large jet transporter to the US military in the 1960s. That contract for what became the C-5A Galaxy eventually went to Lockheed, but Boeing was convinced that its basic design, with its high-bypass turbofan engine, could be reworked for the civilian market, which was booming at the time.

On January 9, 1969, the first 747 prototype took to the skies over Washington state. It was a staggering 225 feet (68.5 m) long, had a wing area larger than a basketball court, and the tail was as high as a six-story building.

Without question the 747 was one of the safest and well designed airplanes ever built. It was years after that first flight before one was involved in an accident, and that was not due to a failure of the plane itself. It also flew like a dream, its large size making it look like it was lumbering slowly in the air. Its retirement is almost entirely related to fuel cost-savings, since the 747 has four engines and thus more fuel than more modern planes.

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