The DART mission was a success: orbit perturbed!

October 12, 2022 • 11:00 am

We’ve had several posts on September 26th’s DART mission—the one in which NASA crashed a small spacecraft into the asteroid Dimorphos at 14,000 miles per hour. The object was to perturb Dimorphos’s orbit around a larger asteroid, Didymos. (DART stands for “Double Asteroid Redirection Test”.) The perturbation was effected by transferring momentum from the DART spacecraft (which crashed in a satisfying cloud of dust) to Dimorphos.

The ultimate goal of this program is to see if we can deflect a comet or asteroid heading towards Earth, staving off the immense destruction that a collision could cause. And, judging by DART, it’s at least possible.

As usual, my old friend and former NASA employee Jim Batterson gives us the details:

Earth Global Defense Test Results (DART Experiment)

Jim “Bat” Batterson

When the NASA/APL (Applied Physics Lab) spacecraft successfully impacted the small asteroid, Dimorphos on September 26, some WEIT readers wanted to know when we would know if it achieved its full mission – an actual perturbation of Dimorphos’ orbit.

 In the post-impact press conference later that day, the mission engineering leadership estimated that the answer would come in a couple of weeks or so as Earth-based telescopes took careful measurements of Dimorphus’ orbital path around its larger companion asteroid, Didymos.  They were right!  Yesterday afternoon, NASA held a press conference at NASA Headquarters in which mission leaders gave us the answer:  the orbit of Dimorphos around Didymos changed significantly – from 11hrs 55min to 11hrs 23min – a 32 minute change.

Here’s the full press conference, an hour long:

The first 30 minutes comprises what I thought was a very informative presentation from three lead project scientists; the final 30 minutes consists of the scientists answering questions from the global press.  They explain in pretty good detail how the orbital change was measured and what these results mean.

Here’s one last video that APL [Johns Hopkins Applied Physics Lab, which partnered in the venture] put out on a summary sheet. The 40-second video compresses the final pics from the DART spacecraft and is really exciting to me. The final frame before blackout due to collision is only 51 ft across, which means the bigger boulders are about ten feet across and the visible small rubble is a foot in size or even smaller.  Incredible technology.

Click on the screenshot below to go to the summary sheet and video. This is the moment before impact:



Guest post: Some post-DART thoughts

September 28, 2022 • 10:00 am

Two days ago, Jim Batterson, an old friend and college classmate who worked for NASA for many years, wrote a precis of the DART mission designed to knock a small asteroid out of its orbit around a bigger asteroid.  He and I were two of the many who watched the “near live” impact of the spacecraft on Dimorphos, and we were both thrilled. Here’s the last 18 seconds before impact:

Here, from Facebook, is a telescopic view from Earth of the moment the spacecraft hit Dimorphos (credit: Atlas Project):


After I mentioned to Jim that this was the first time we tried to perturb an orbit with a spacecraft, he sent me his thoughts on the mission and reminded me of a few instances of other impacts or landings on celestial bodies, though these didn’t have the same goal as DART.  With his permission I submit Jim’s thoughts for your approval.

Some Post-DART Mission Thoughts 

Jim Batterson

Now that the excitement and really spectacular success of the DART asteroid rendezvous and impact is in the rearview mirror, I want to remind readers of some earlier space missions that were akin to DART in an engineering sense.

Much of what NASA does in space missions is “engineering in the service of science”.  That is, NASA scientist and engineers, in consultation with scientists from around the world, are responsible for managing and assuring the design of appropriate missions, building (often unique) scientific instruments, and developing the rockets and spacecraft to fly those instruments to a point in space (sometimes on a planet or simply in a planetary atmosphere) where collected data is returned for analysis to scientists on Earth.  Comet rendezvous missions are traditionally “pure science” missions to gather unique data on the composition of comets, as it’s thought that a better understanding of comets will lead to a better understanding the formation and early years of our solar system.

DART was a different type of mission, not only in its focus on an asteroid rather than a comet, but also in that it kept its engineering mission for planetary defense pretty clean and did not try to add in a large suite of scientific instruments to gather data.  That said, there have been several comet flybys over years and two comet impacts

The impacts were these:

Deep Impact by NASA/Jet Propulsion Lab (JPL). Upon rendezvousing with the Comet Temple-1 on July 4, 2005, the Deep Impact spacecraft launched an impactor craft that smashed into the comet’s nucleus.  The debris cloud and crater were then photographed and analyzed by instruments on the mother ship. Here’s a NASA photo with this caption:

This spectacular image of comet Tempel 1 was taken 67 seconds after it obliterated Deep Impact’s impactor spacecraft. The image was taken by the high-resolution camera on the mission’s flyby craft. Scattered light from the collision saturated the camera’s detector, creating the bright splash seen here. Linear spokes of light radiate away from the impact site, while reflected sunlight illuminates most of the comet surface. The image reveals topographic features, including ridges, scalloped edges and possibly impact craters formed long ago.

Source: NASA/JPL-Caltech/UMD

The Rosetta/Philae mission was carried out by the European Space Agency (ESA) in 2014. Upon rendezvous with Comet 67P after an almost eleven-year journey through space, the Rosetta spacecraft launched a lander (Philae) whose purpose was to soft-land on the comet and drill into its surface, gathering data on the comet’s interior. ESA was partly successful as Philae did make it to the surface. But some of its propulsion equipment failed to operate properly to slow it down completely, so it suffered a hard landing and bounced, leaving Philae in a crevice. This prevented it from accessing sunlight needed to recharge its batteries.  Sadly, the subsurface data couldn’t be collected.

However, it did survive to take some incredible photos on the actual surface of a comet nucleus. I think that this was still an extraordinary accomplishment. You can see the photos here.

[JAC: I’ll present one example, a fantastic selfie taken by Philae as it sat in the crevice. The caption is

“The Philae lander of the European Space Agency’s Rosetta mission is safely on the surface of Comet 67P/Churyumov-Gerasimenko, as these first two images from the lander’s CIVA camera confirm. One of the lander’s three feet can be seen in the foreground. The view is a two-image mosaic taken on Nov. 12, 2014.”]

DART didn’t even pretend to be about collecting basic science data, but rather was about using engineering expertise developed over our spacefaring years to help the protect our planet. This was an important proof of a “concept mission” in which the concept was that, if an asteroid were given a proper nudge, its trajectory could be changed enough to move it from a collision course with Earth to a harmless close encounter. This was a test or experiment to gather engineering data. It is a high-school physics problem to show that it works in theory, but would it work in the real world?

I think that one of big engineering challenges for the DART test was navigating and guiding using the light from the two-asteroid system and then, a few minutes before scheduled impact, to autonomously focus on and keep the smaller, dimmer asteroid as its target.  This was especially challenging because the engineers had no real knowledge of the reflective characteristics or shape of either body. It turned out, as we all saw in the final couple of minutes of approach, that both bodies were non-spherical with lots of surface irregularities, which scatter sunlight in all directions and cast shadows. But the software had been designed with enough robustness to deal with these non-ideal bodies.

For folks who want to learn more about Near-Earth Objects, I recommend Donald Yeomans’ 2013 book, Near-Earth Objects: FindingThem Before They Find Us (Princeton) as an excellent summary the general reader.

Russians destroy world’s largest airplane in Kyiv

May 19, 2022 • 12:45 pm

This article was in the April 22 issue of the New York Times, but has languished among my 1,737 draft posts. And compared to the toll of human lives following the Russian invasion, this can only be a footnote. But it’s an intriguing footnote, for it describes how a Russian hit on Antonov airport near Kyiv, in Ukraine, destroyed the world’s largest aircraft. That would be a plane manufactured in the Ukraine when it was part of Russia and flown (as a cargo plane) by Ukrainian pilots.

That plane would be the  Antonov An-225 Mriya. How big was it? Let Wikipedia give the stats:

With a maximum takeoff weight of 640 tonnes (705 short tons), the An-225 held several records, including heaviest aircraft ever built and largest wingspan of any aircraft in operational service. The Mriya attracted a high degree of public interest, attaining a global following due to its size and its uniqueness. People frequently visited airports to see its scheduled arrivals and departures.

. . . Initially, the An-225 had a maximum gross weight of 600 t (660 short tons; 590 long tons), but from 2000 to 2001, the aircraft underwent modifications at a cost of US$20 million, such as the addition of a reinforced floor, which increased the maximum gross weight to 640 t (710 short tons; 630 long tons).

Both the earlier and later takeoff weights establish the An-225 as the world’s heaviest aircraft, being heavier than the double-deck Airbus A380. It is surpassed in other size-related categories, but Airbus claims to have improved upon the An-225’s maximum landing weight by landing an A380 at 591.7 tonnes (1,304,000 lb) during tests, and the Hughes H-4 Hercules, known as the Spruce Goose, has a greater wingspan and a greater overall height, but the Spruce Goose is 20% shorter and overall lighter, due to the materials used in its construction. In addition, the H-4 only flew once and for less than a minute, making the An-225 the largest aircraft in the world to fly multiple times.

And from the NYT:

At 276 feet long and six stories high, the plane, designated AN-225, was bigger than any other in the sky. It boasted 32 landing wheels and a wingspan of 290 feet. Its maximum takeoff weight stood at a staggering 1.4 million pounds, far more than a fully loaded 747. Its nose cone flipped up so that big objects, like turbine blades or even smaller jets, could be slid into its cavernous belly.

Here’s why people would watch it take off:

And look at its main landing gear!

Six engines, six contrails:

A Russian missile scored a direct hit on Mriya’s hanger, turning it to fragments. Here’s a video about that:

The NYT describes the sorrow attending the destruction of this one-of-a-kind plane, especially from its pilot:

In the case of Mriya, which took a direct hit during the pivotal battle at that airport, the damage to the aircraft has stirred an incredible outpouring of what can only be described as grief. Heartbroken airplane buffs around the world are getting Mriya tattoosA sad cartoon has been circulating, with tears streaming out of Mriya’s eyes.

“If I were not a man,” he said, “I would cry.”

The plane after it was hit.  The NYT says that “All might not be lost, though. The Ukrainian government, knowing the power of Mriya’s symbolism, has vowed to rebuild her with war reparations it hopes to squeeze from Russia.”  I wouldn’t hold my breath.

From the NYT: Haluneko finally worked up the courage to visit the plane to see the damage to the plane he flew many times:

And another photo from the NYT: of Halunenko with his beloved plane:

And another epic takeoff for you plane buffs:

Indigenous electrical wiring in New Zealand

February 10, 2022 • 10:30 am

There are apparently a lot of Kiwis who agree with my view that Mātauranga Māori (“MM”), or Maori “ways of knowing”, should not be given coequal status with modern science in science classes. (It should be taught mostly as anthropology or history, with the bits of “practical knowledge” perhaps interpolated in science class.)  This is a losing battle, I know, as are most battles against forms of wokeness, but as a scientist I want to at least make my views known and try to keep science teaching on the rails. Forcing MM—a mixture of legend, theology, morality, mythology, and practical knowledge—into science class constitutes a form of “valorizing the oppressed” by giving them certain rights that make no sense in today’s world. Teaching Māori legends and myths (including creationism) as real science in biology or physics class is one of those “rights” that needs to be ditched.

Nearly every day I get emails from upset Kiwis, some with Māori heritage, who agree with me. After all, no sensible person wants to see science education in their country be watered down this way. But almost all of these people are afraid to speak up publicly or use their names. That’s because questioning the scientific nature of MM is considered a big no-no in New Zealand, and you can lose your job for it. The Royal Society of New Zealand, for instance, is still investigating two of its members for taking the stand I described above.  The disaffected Kiwis write me because I can give voice to their concerns without getting them in trouble.

Another Kiwi sent me the figure below, along with an email. I have permission to quote so long as names aren’t used. Note that this person is a lover of his country and an admirer of the Māori.

From the email:

This week I was doing some electrical updates, and thought I should first check the NZ regulations for wiring (colors, etc). All very straightforward, and the project was a success. Nonetheless, in light of some of your (absolutely correct) commentary on NZ recently, I thought you might be interested in the attached page from the regulations.  All I can say is ….. wha ????

Having lived overseas for a while, I really cannot comment very knowledgeably on New Zealand’s directions. The day to day celebration of Māori culture, and the things that make NZ so unique, are great, and even my own family use many Māori words in everyday speech that I would not have recognized in my childhood.
But the extension into other areas, such as your observations about science education, and this document I shared, add zero value and smack of opportunistic woke-ism. I simply don’t believe that a young Māori looking to become an electrician would find that path easier by thinking of electrical ground as the realm of some mythological entity.
I put a red box around the relevant bit from the New Zealand Electrical Code of Practice :

Note that there is nothing helpful or practical in this addition; what it does is analogize the practical instructions for wiring with certain terms from MM. No serious harm is done with this, but I think it shows the fealty to MM that permeates nearly every aspect of NZ life—including wiring. It is in fact kind of funny, but also sad, because it valorizes mythology by adding it to advice for electricians.

I have to add, though, that the person who sent me this stuff has good things to say about his country’s government, and I agree. Not only did they do fantastically well against Covid, but they’re doing a really good job trying to conserve their beleaguered wildlife using modern (not MM) conservation techniques. It’s a beautiful country with lovely people, and I hope to return before too long.

The last bit of the email I got:

Jacinda Arden’s leadership in the early years of her Prime Minstership have been exemplary in terms of standing against COVID and terrorist actions, with a consistency of message and direction sorely lacking in the US and UK.  And for COVID, the result is undeniable:  NZ’s total deaths over 2 years are comparable to a single day in Massachusetts with its similar population. But the challenge for her now is the transition to a re-opened country, and coping with an increasingly frustrated, impatient populace. And it is sorely costing her the polls.

The Presidential motorcade

February 4, 2022 • 2:30 pm

I had no idea that constructing a motorcade to protect the President—as well as a car that could shield the President from nearly any assault—was so complex! I found this video of how the Prez drives from point A to point B fascinating, as well as the way that the (two) Presidential limousines are constructed. They’re like James Bond vehicles! They even have blood for transfusion in them, as well as tons of weapons and a smoke emitter.  $1.5 million for each vehicle!

James Webb Space Telescope

December 20, 2021 • 11:30 am

On Wednesday, as the 13-minute “60 Minutes” segment below explains, the $10-billion-dollar James Webb Space Telescope will be launched.  Thirty days later, it will be nearly a million miles from Earth, in orbit around the Sun.

One of its goals is to detect leftover radiation traveling over billions of light years, giving us a glimpse of the past and, perhaps, into what “dark matter” is.  But, as you’ll see, it can also answer many other questions.

If you want to read more than you’ve absorbed from this segment, go to either the Wikipedia page or on the telescope’s NASA site.

I’m continuslly stunned by what humans can do with simple materials extracted from the Earth. And it’s great that this effort involves international cooperation.

h/t: Nicole

Waddles the Duck gets a prosthetic leg

June 10, 2021 • 2:30 pm

OMG they made a prosthetic leg for a male mallard and it works! Is there anything more satisfying than seeing a lame duck walk again? It takes Waddles a bit to learn how to walk, but we’re reassured that he’ll get better and better with time.

Nerdist tells us a bit more of the story, but not of the fate of Waddles and his new leg. But there is also some general information:

Laughing Squid picked up on Waddles first-ever go-round with his new, prosthetic leg. The crew at Bionic Pets made the leg for the wildly cute duck in an attempt to vastly improve his quality of life. And in the video clip above from the National Geographic show, The Wizard of Paws, we see Derek Campana from Bionic Pets strap Waddles to his fun, faux leg for the first time.

. . . Campana says this tech’s “not only cool for Waddles, but for all the birds to come” who’ll also benefit from cutting-edge prosthetics. Indeed, we’ve perused the Bionic Pets site, and Campana and company are working on some seriously cool animal prosthetics.

Kudos to all the people who care enough to help hobbled animals live a good life.

h/t: Jean, Tim

Livestream on the Mars helicopter starts now. IT FLEW!

April 19, 2021 • 5:15 am

UPDATE: Everything appears to have been copacetic: the flight was successful and there are even photographs from the rover.  First is a photo from the Ingenuity showing its shadow on Mars, and the second is a photo from the Rover showing the Ingenuity in the air!

According to the NYT, the Mars helicopter Ingenuity, which weighs only about four pounds, has already attempted its first flight, but we don’t yet know the results as they must be transmitted to Earth. I’m posting this at 5:15 Eastern time, when that data and perhaps video on the flight are supposed to start arriving. The first go will be a short hop, only about 30 seconds long, and the video link is at the bottom. Given the thinness of Mars’s atmosphere (offset a bit by its lower gravity), this feat has been compared to flying a helicopter at an Earth altitude of 100,000 feet—something that’s never been done.

A gif of the Ingenuity (courtesy NASA/JPL CalTech):

From the paper:

At the Ingenuity site on Mars, which is within an ancient crater named Jezero, it will be the middle of the day, about 12:30 p.m. local Mars solar time. (The time zones on the red planet don’t have names, yet.)

For people on Earth, that translates to about 3:30 a.m. Eastern time on Monday. But no one on Earth will know for hours whether the flight has succeeded or failed, or if anything has happened at all. Neither Ingenuity nor Perseverance will be in contact with NASA at that time.

Instead, the two spacecraft will conduct the flight autonomously, executing commands that were sent to them on Sunday. Later, Perseverance will send data back to Earth via a spacecraft orbiting Mars.

NASA TV will begin broadcast from the control room at NASA’s Jet Propulsion Laboratory beginning at 6:15 a.m. Eastern time as the data starts arriving on Earth. You can watch it on NASA’s website.

I’ve put the NASA YouTube feed below:

Additional information will be provided at a news conference at 2 p.m. Eastern time on Monday.

Click below to watch, and fingers crossed. Look how young all the kids are in the helicopter control room!

The Wikipedia article on Ingenuity gives a lot of useful information, and the most poignant piece is this:

Ingenuity carries a piece of fabric from the wing of the 1903 Wright Flyer, the Wright Brothers‘ airplane, humanity’s first controlled powered flight on Earth.

Can you imagine how the Wright brothers would have reacted had they been told 118 years ago that part of their own plane would be flying on Mars?

Transiting the Suez Canal: a lovely video

March 31, 2021 • 2:30 pm

Since the Ever Given got stuck in the Suez Canal (it’s now freed), a lot of us have been looking up the Canal, and asking questions like “can ships go both ways at the same time?” (Answer: yes, if they use the bypasses, but ships usually travel in convoys, two southbound and one northbound.)

What does it cost to go through? It’s expensive: an average of $250,000 (US) per vessel.

You can learn everything you need to know from the Wikipedia article on the canal, including when it was built: surprisingly long ago, between 1859 and 1869. A few essential facts:

 It offers vessels a direct route between the North Atlantic and northern Indian oceans via the Mediterranean Sea and the Red Sea, avoiding the South Atlantic and southern Indian oceans and reducing the journey distance from the Arabian Sea to London by approximately 8,900 kilometres (5,500 mi), or 8 days at 24knts (JAC: “knots”) to 10 days at 20knts. The canal extends from the northern terminus of Port Said to the southern terminus of Port Tewfik at the city of Suez. Its length is 193.30 km (120.11 mi) including its northern and southern access-channels. In 2020, more than 18,500 vessels traversed the canal (an average of 51.5 per day).

Here’s a satellite photo of the Canal.

And a diagram of the complex setup. I always wondered if there was a bridge over it, and there is one, as well as a tunnel.

This is all an excuse to show this lovely 2½-minute GoPro video of a ship going through the canal in real time; a passage takes 11-16 hours because low speeds are mandated.

The music is a bit annoying, so you might want to turn the sound off.

You can see a similar transit of the Panama Canal (11 hours) here. I actually did half of this while lecturing on a Sci Am cruise to the Caribbean. We went through the locks, guided by those powerful “mule trains” that serve not to power the ship (it steams under its own power), but to guide it and keep it centered in the locks. After going to Lake Gatun (I got off to visit the Smithsonian Tropical Research Institute in an island in the lake), we turned around and went back out to the Caribbean.

Lagniappe: Burger  King put out an ad showing a Double Whopper blocking the Canal, presumably because of its size. Predictably, some of The Easily Offended got upset, and gave several reasons for their distress.