Mapping the break-up and impact of one of the first asteroid’s tracked from space to the ground

Computer simulation of asteroid break-up
Click for full figure.

By analyzing 600 scattered pieces recovered from a 20-foot wide asteroid that broke-up and landed in the Sudan in 2008, scientists have discovered that some surface pieces were able to reach the ground unscathed because they were on the asteroid’s protected aft as it plowed through the atmosphere.

This asteroid was one of the first ever discovered shortly before impact and then tracked as it hit the atmosphere and broke up, the pieces falling as meteorites. The image to the right, figure 4 of the paper, shows the computer simulation of the asteroid’s break-up, based on the data obtained by mapping the location of its pieces on the ground. From the press release:

“Because of the high speed coming in, we found that the asteroid punched a near vacuum wake in the atmosphere,” says Robertson. “The first fragments came from the sides of the asteroid and tended to move into that wake, where they mixed and fell to the ground with low relative speeds.”

While falling to the ground, the smallest meteorites were soon stopped by friction with the atmosphere, falling close to the breakup point, while larger meteorites were harder to stop and fell further downrange. As a result, most recovered meteorites were found along a narrow 1-km wide strip in the asteroidโ€™s path. “The asteroid melted more and more at the front until the surviving part at the back and bottom-back of the asteroid reached a point where it suddenly collapsed and broke into many pieces,” said Robertson. “The bottom-back surviving as long as it did was because of the shape of the asteroid.”

No longer trapped by the shock from the asteroid itself, the shocks from the individual pieces now repulsed them, sending these final fragments flying outwards with much higher relative speed. “The largest meteorites from 2008 TC3 were spread wider than the small ones, which means that they originated from this final collapse,” said Jenniskens. “Based on where they were found, we concluded that these pieces stayed relatively large all the way to the ground.”

The location of the large meteorites on the ground still reflects their location in the back and bottom-back part of the original asteroid.

While there is a certain randomness in how any asteroid breaks up, this data will help scientists better understand the make-up of future meteorites they find. The bigger more widely scattered pieces likely came from the asteroid’s rear surface.

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Further damage to Curiosity’s wheels

Curiosity wheel comparison of damage
For the original images, click here for the top photo and here and here
for the bottom photo.

The photo comparison to the right, created from high resolution images taken by Curiosity on Mars two months apart, provides us a new update on the state of the rover’s damaged wheels. It shows damage on the same wheel that I have been tracking for several years.

The numbers indicate the same treads, or grousers as termed by the science team. The “+” sign indicates spots where new damage has occurred since the previous photo.

The top photo was taken on June 3, 2022, and was the first to show new damage in more than five years. The bottom photo was taken on August 6, 2022, and shows that another small piece on the same grouser has broken off during the past two months.

Other than this change, however, the rest of the grousers appear unchanged. Moreover, a comparison with an earlier image of this same wheel taken in the summer of 2021 shows that grouser #6 as well as the unnumbered one just below appear also unchanged.

The damage in grouser #5 however is still concerning, and reflects the increasing roughness of the terrain as Curiosity climbs higher and higher on Mount Sharp. Though the science team has been very careful since the rover’s first few years on Mars to travel around obstacles that could damage the wheels, it apparently is becoming harder to do so.

However, even if this wheel eventually loses all the metal between the zig-zag grouser treads, the science team has said it has “proven through ground testing that we can safely drive on the wheel rims if necessary.” The team as also said they do not think that is likely, at least not for a long time, and based on the rate of damage documented by these pictures, this appears very true.

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India’s new SSLV rocket fails on first launch attempt

Delayed years because of India’s panic over the Wuhan flu, the first launch of that country’s new Small Satellite Launch Vehicle (SSLV) failed today when the rocket’s fourth stage apparently did not fire its engines properly.

The problem appeared to be the SSLVโ€™s terminal stage, called the velocity trimming module (VTM). According to the launch profile, the VTM was supposed to have burnt for 20 seconds at 653 seconds after launch. However, it burnt for only 0.1 seconds, denying the rocket of the requisite altitude boost. Two satellites onboard the rocket โ€“ the primary EOS-2 Earth-observing satellite and the secondary AzaadiSAT student satellite โ€“ separated from the vehicle after the VTM burnt.

As a result, the two satellites were put in an orbit that was too low, which quickly decayed, destroying both.

Since this launch failed, I do not count it in the launch totals for 2022.

Considering that this was SSLV’s first launch, it was in that sense a test, and a failure therefore is not unexpected. India’s real problem is that the launch was delayed so long because of the Wuhan panic, thus allowing other competitors to catch up and pass India. While it is certain ISRO will try again, and eventually succeed, it will not get the market share it would have had, had it launched in 2020 as originally planned.

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SpaceX raises another $250 million in investment capital

Capitalism in space: SpaceX in July raised $250 million in investment capital from five unnamed investors, bringing the total raised in 2022 to $2 billion.

Added to the amount brought in before this year, SpaceX has raised about $9 billion in private capital, most of which is focused on financing the development of Starship/Superheavy. When you add the $2.9 billion contract it won from NASA to develop Starship as a manned lunar lander, the company has raised about $12 billion to build this heavy lift rocket.

The numbers demonstrate several things. First, Wall Street is apparently very confident SpaceX will succeed in building the rocket, and then make a lot of money from it. Second, the numbers prove it shouldn’t cost $60 billion and two decades to design and build a heavy lift rocket, as NASA has done with its SLS rocket. SpaceX is doing it for less than a fifth of the cost, in a third of the time.

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Strange terrain southwest of Jezero Crater

Strange terrain near Jezero Crater

Cool image time! The photo to the right, cropped and reduced to post here, was taken on June 16, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists have merely label “landforms.”

I instead call them strange. Clearly we are seeing exposed layering that surrounds the mesa in the middle of the image. This in turn suggests that the mesa top was once the surface of this whole region, and that region had been formed by the repeated placement of multiple sedimentary layers. Then, over time the surrounding terrain was eroded away, exposing those underlying layers.

Even so, some of the parallel lines do not appear to be layers, but striations etched into the ground. To get a better look, the white box marks the area covered by a full resolution close-up below.
» Read more

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Curiosity celebrates ten years on Mars

Curiosity's location in Gale Crater

Sometime today the rover Curiosity will celebrate its tenth anniversary on Mars. The oblique graphic of Gale Crater above, first released by the science team shortly before landing in 2012, has been further annotated with a red line to show the rover’s journey since then. As noted by Scott VanBommel, Planetary Scientist at Washington University, today on the science team’s blog:

As we the science and engineering teams have aged this last decade, so has Curiosity. The toll of ten years and nearly 28.5 km [17.7 miles] of Mars driving shows with every MAHLI wheel imaging activity, with less energy available for a plan, and with aging mechanisms. This is the life of a Mars rover. Spirit and Opportunity were no different, yet they persisted and paved the way scientifically and technologically for the rovers of today. Curiosity has made numerous scientific discoveries during these ten years, emphasized by the over 500 science team publications, with many more ahead as we continue our ascent and exploration of Gale crater and Mount Sharp.

I look forward to the next ten years.

Despite that aging, Curiosity’s general condition appears quite excellent, with its wheels the greatest concern but generally holding up. Based on the last ten years, the rover is likely to remain operational for at least ten more years, if not longer.

In the more immediate future, the rover is only days away from getting its first good look down into Gediz Valles, that canyon on the graphic above that it has been traveling towards since day one.

A good review of five of Curiosity’s biggest discoveries using its sample analysis instrument can be found here.

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Virgin Galactic once again delays commercial suborbital operations

Capitalism in space: In releasing its quarterly report, Virgin Galactic yesterday revealed that it is once again delaying the start of commercial suborbital operations, pushing back from the first quarter of 2023 to the second quarter.

In an earnings call, company executives said that the latest delay was not directly related to supply chain and staffing problems it blamed for the previous delay. Instead, refurbishment work on its WhiteKnightTwo plane, VMS Eve, was taking longer than planned. โ€œThe driver is around the amount of time it is taking us to accomplish the work scope on Eve,โ€ said Michael Colglazier, chief executive of Virgin Galactic. โ€œWe did not plan the full amount of time thatโ€™s been needed to get this work accomplished.โ€

Company officials also said they are shifting its customer emphasis, now focusing much more on “private and government researchers.” Let me translate: The public is not buying tickets, so Virgin Galactic hopes to convince the government to keep it afloat instead.

I predict this company will likely never fly any customers, and it appears the stock agrees, with the stock plunging in value, from $8.25 to $6.95 in less than a day.

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Astra cancels all launches with its Rocket 3.3 rocket

Capitalism in space: Astra yesterday announced that it has canceled all further launches with its Rocket-3.3 rocket, and will instead focus on developing a larger version, dubbed Rocket-4, which it says will begin test flights in 2023.

The company says that it will no longer fly the Rocket 3.3 and move on to its larger Rocket 4 vehicle that it announced in May. One change is that the payload performance of the new rocket has doubled to 600 kilograms. Kemp didnโ€™t disclose details of the design change other than an upgrade to its upper stage engine. Rocket 3.3, by contrast, had a payload capacity of no more than 50 kilograms.

โ€œThe feedback that we were getting from some of the larger constellation operators was that satellites were getting larger,โ€ he said. Discontinuing the existing Rocket 3.3, he said, allowed the company to focus its resources on the new launch system, including increasing its payload capacity.

Essentially, Astra has left the field and is at present no longer an operational smallsat rocket company. It is also likely that its announced schedule for its upgraded rocket will not be met. Thus, expect customers to shift to other launch providers able to launch satellites, such as Rocket Lab and Virgin Orbit.

Not surprisingly, the company’s stock plunged soon after this announcement.

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SpaceX launches South Korea’s Danuri lunar orbiter

SpaceX today successfully launched South Korea’s Danuri lunar orbiter, also called the Korea Pathfinder Lunar Orbiter.

The first stage completed its sixth flight, landing on a drone ship in the Atlantic. The fairings completed their fourth flight.

Danuri is now on its way to the Moon, with a planned arrival in lunar orbit on December 16, 2022. It carries six instruments, one of which was developed by NASA. The spacecraft, while designed to study the Moon, is primarily a technology test mission laying the groundwork for more sophisticated interplanetary South Korean missions. More information about the mission can be found here.

The leaders in the 2022 launch race:

34 SpaceX
28 China
10 Russia
6 Rocket Lab
5 ULA

The U.S. now leads China 49 to 28 in the national rankings, and the entire world combined 49 to 45. With this launch American private enterprise has now surpassed the entire launch total for all of 2021, and has the most launches for the U.S. since 1967, when it completed successfully 57 launches.

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China launches “reusable experimental spacecraft”

According to the official Chinese press, China today successfully used its Long March 2F rocket to place into orbit a “reusable experimental spacecraft.”

To say the information provided was terse is to be extravagant. This is it:

After a period of in-orbit operation, the spacecraft will return to its scheduled landing site in China. It will test reusable technologies and in-orbit service technologies as planned during its flight, providing technological support for the peaceful use of space.

It appears, based on the size of the rocket, that this spacecraft is likely a copy of Boeing’s X-37B.

The leaders in the 2022 launch race:

33 SpaceX
28 China
10 Russia
6 Rocket Lab
5 ULA

The U.S. still leads China 48 to 28 in the national rankings, and the entire world combined 48 to 45.

These numbers should change within the next half hour, as SpaceX is about to launch another rocket.

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Glacial flows pushing out through a Martian crater rim

Wider view of 6-mile-wide crater
Click for full image.

Today’s cool image once again illustrates how Mars is far from a waterless planet. Instead, there is strong evidence that water ice can be found across most of the Red Planet’s surface, excluding the equatorial regions lower than 30 degrees latitude.

The photo to the right was taken on September 11, 2021 by the wide view context camera on Mars Reconnaissance Orbiter (MRO). It shows a 6-mile-wide unnamed crater on Mars, located at 35 degrees south latitude, with what appears to be a glacier in its interior, flowing to the southwest towards several breaches in the crater’s southwest rim. Several of those breaches now sit higher than the flow, suggesting that the glacier itself was once higher and flowed out of those gaps. Now the level has dropped, and the only place the glacier exits the crater is the central gap at the center of the white rectangle.

That white rectangle marks the area covered by a recent MRO high resolution image, taken on March 29, 2022 and cropped and reduced to post below.
» Read more

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Axiom signs deal with New Zealand

Capitalism in space: The private space station company Axiom has now signed a deal with New Zealand to permit its citizens to propose and fly experiments on future Axiom missions, both to ISS and to Axiom’s own space station, scheduled for launch beginning in ’24.

This is the fourth international commercial agreement Axiom has signed since May, with Italy, Hungary, and the UAE the signatories in the previous deals. The UAE deal also included the launch of a UAE astronaut to ISS for a six month flight.

Axiom hopes to launch its first module to ISS in ’24, with later modules eventually allowing it to undock its section to fly as an independent station when ISS is retired.

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