Author: Robert Zimmerman

Three Starship prototypes in line for testing

9:14 am

Capitalism in space: SpaceX’s assembly line for building Starship prototypes is heating up, with three such ships completed or under construction in Boca Chica, Texas.

Initially numbered 5 through 7, the goal of the first two will be to do the first full scale vertical hops, flying as high as 7.5 miles.. #7 however has a different purpose:

While stouter than an actual Starship-class methane or oxygen tank, this particular test tank is maybe only 25% shorter than the methane tanks installed on Starship prototypes. According to Musk and effectively confirmed by writing all over the prototype, this particular test tank – formerly Starship SN7 – was built to determine if a different kind of steel could be preferable for future ships.

Shortly after the June 15th test began to wind down, Musk announced that the new material (304L stainless steel) had performed quite well, reaching 7.6 bar (110 psi) before it sprung a leak. The fact alone that it sprung a leak instead of violently depressurizing is already a major sign that 304L is preferable to 301L, as it means that Starships built out of it could fail much more gracefully in the event of a leak instead of collapsing or violently exploding. A step further, SpaceX has already managed to repair the leak on SN7 and will likely test the tank again in the next few days.

SpaceX is once again demonstrating how to properly do this kind of cutting edge development. You test, you fix or, you change, based on what your tests tell you. You don’t lock down design in the early stages, because at that point you really don’t know enough to do so.

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Astra schedules next launch attempt

9:01 am

Capitalism in space: The smallsat rocket company Astra has scheduled its next launch attempt for July 20.

The company tried twice to launch in March, with the second attempt destroying the rocket and launchpad. They have now rebuilt, though they also admit that this first launch might also fail, and that it is part of a three launch program. By the third launch they expect to reach orbit for sure.

If Astra succeeds, they will leap ahead of Virgin Orbit as the second smallsat rocket company, following Rocket Lab, to become operational.

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Enigmatic layering and chasms on Mars

2:27 pm

Enigmatic layering and chasms
Click for full image.

Overview map

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on April 28, 2020 by the high resolution camera on Mars Reconnaissance Orbiter. (MRO). The science team entitled it “Enigmatic Uplifts in Echus Montes,” indicating a sense of bafflement on their part about this geology.

The features here are certainly somewhat puzzling. At first glance the terrain is reminiscent of Martian chaos terrain, mesas cut by canyons in an almost random pattern. As I explained at the link,

Chaos terrain is typically a collection of mesas separated by straight-lined canyons. It is found in many places on Mars, most often in the transition zone between the southern highlands and the northern lowlands where an intermittent ocean might once have existed. It is believed to form by erosion, possibly caused by either flowing water or ice, moving along fault lines. As the erosion widened the faults, they turned into canyons separating closely packed mesas. With time, the canyons widened and the mesas turned into a collection of hills.

What makes this particular image puzzling however is that there seem to be multiple layers of mesas and canyons. Look at the top of the rectangular mesa in the upper middle of the image. It appears to have its own miniature chaos terrain on its plateau. Somehow that first layer of chaos was abandoned when the more prominent larger canyons started to form around it.

The location of this feature is indicated by the black cross on the overview map to the right. It is in the middle of the large and wide northward trending part of the giant valley dubbed Kasei Valles. And as usual, knowing the location helps explain what we are seeing.
» Read more

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A fast radio burst that beats every sixteen days

11:59 am

Astronomers have now added to the mystery of fast radio bursts (FRBs), of which about a hundred are known, by discovering one in a nearby galaxy that has a regular outburst every 16.35 days.

Earlier this year CHIME worked with astronomers in Europe to pinpoint the origin of a particular FRB emission — called FRB 180916.J0158+65 — to a galaxy located 500 million light years from Earth.

Now CHIME has determined that FRB 180916 pulses at predictable intervals more than two weeks apart. “It tells us that the origin of at least some FRBs is astrophysically regular in nature, but on long enough time scales that they may be tied to something different than a rotating, compact object — perhaps something like an orbiting system,” said Newburgh, whose lab builds instrumentation for collecting data about the history of the cosmos

Or to put it another way, they really haven’t any idea yet what exactly causes these bursts. The new data however will help formulate better theories, that I guarantee will be contradicted by subsequent new data. At the moment there is so little known about FRBs that any theory must be looked at with great skepticism.

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U.S. & U.K. sign space agreement

11:41 am

Anticipating the exit of the United Kingdom from the European Union, the Trump administration has signed an new space agreement with the U.K. in order to facilitate the ability of U.S. companies export British technology as well as launch from its spaceports.

I cannot find the actual text of the agreement so my description, based on news reports and the press release (linked above) might be wrong. It does appear however that the agreement is designed to smooth out the regulatory environment that might block commercial space development involving both countries.

It also seems required because of the UK’s exit from the EU. They need to sign bilateral agreements with other nations to replace the EU framework.

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SpaceX hiring engineers for building floating Starship spaceport

10:04 am

Capitalism in space: SpaceX has issued advertisements looking for two engineers to help build an offshore floating spaceport for launching its Starship/Super Heavy reusable rocket.

This plan is not really a surprise, as Musk from his first description of Starship said that it would likely launch and land on floating platforms. The rocket is big, so putting its launch and landing in the ocean reduces the risk to populated areas, while giving the company some flexibility about where it will land. The latter point reinforces the company’s stated goal of using this rocket not only to make interplanetary travel affordable but to also provide point-to-point transportation on Earth.

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Yutu-2 to resume travels after day of rest

9:58 am

The new colonial movement: After lunar day of no activity, China has reactivated its Yutu-2 rover on its 19th lunar day on the far side of the Moon.

The Yutu 2 rover had remained stationary during lunar day 18 (May 16-29), while teams back on Earth upgraded ground stations in preparation for the Tianwen-1 Mars mission, due to launch in late July or early August. Upgrades to the tracking and command facilities at Jiamusi, northeast China, and Kashi in the northwest were completed June 13 according to CLEP, meaning normal roving service can now resume.

While the rover has been stationary, the Yutu 2 science team have identified a nearby crater for examination. The 4-foot-wide (1.3 meters), 8-inch-deep (20 centimeters) crater contains reflective material which may be similar in nature to suspected impact melt glass the rover discovered last year. After checking out the crater, Yutu 2 will continue its journey northwest from the Chang’e 4 landing site. Yutu 2 has driven a total of 1,469 feet (447.68 meters) since setting down on the far side of the moon in January 2019.

Generally Yutu-2 has averaged about a hundred feet for each lunar day of actual travel.

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NOAA awards contract to private company for solar observatory

9:22 am

Capitalism in space: NOAA today awarded a contract to the private company Xplore to study development of a commercial solar observatory at the Earth-Sun L1 point.

The press release at the link is somewhat vague about the contract. It appears to be a study to see if Xplore’s proposed Xcraft spacecraft can be used as platform for such a solar observatory, not an actual contract to build the observatory.

Regardless, this award is a strong indicator that the Trump administration is applying pressure at NOAA to get it out of the business of building weather satellites and instead be a customer buying such satellites from the private sector. The weather agency has been, like NASA earlier this decade, resistant to this concept, with its bureaucracy wanting to retain control over everything. Maybe the success of SpaceX at NASA is now helping to fuel the change at NOAA.

Let us hope so. NOAA’s present fleet of solar observatories in space is years past their due date, with no sign of a replacement fleet. The agency just can’t seem to get its act together to build these satellites. For example, NOAA has been trying and failing to build a new solar observatory to monitor sunspot activity now for more than a decade.

Maybe, like NASA, giving the job to private enterprise might get things going.

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Astronomers discover giant arc spanning a third of the night sky

9:05 am

Astronomers have discovered a giant arc of hydrogen gas near the Big Dipper that span a third of the night sky and is thought to be the leftover shockwave from a supernova.

Ultraviolet and narrowband photography have captured the thin and extremely faint trace of hydrogen gas arcing across 30°. The arc, presented at the recent virtual meeting of the American Astronomical Society, is probably the pristine shockwave expanding from a supernova that occurred some 100,000 years ago, and it’s a record-holder for its sheer size on the sky.

Andrea Bracco (University of Paris) and colleagues came upon the Ursa Major Arc serendipitously when looking through the ultraviolet images archived by NASA’s Galaxy Evolution Explorer (GALEX). They were looking for signs of a straight, 2° filament that had been observed two decades ago — but they found out that that length of gas was less straight than they thought, forming instead a small piece of a much larger whole.

This is a great illustration of the uncertainty of science. Earlier observations spotted only 2 degrees of this arc, and thus thought it was a straight filament. Newer more sophisticated observations show that this first conclusion was in error, that it was much bigger, and curved.

I wonder what even more and better observations would reveal.

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