Space Sunday: a little astronomy and a round-up

Artist’s conception of a magnetar — a super dense neutron star with an extremely strong magnetic field. In this illustration, the magnetar is emitting a burst of radiation. Credit: Sophia Dagnello, NRAO/AUI/NSF

Fast radio bursts (FRBs) are one of the strangest phenomena we’ve yet discovered in the cosmos – and they are also one of the most recent, the first one only being detected in 2007.

FRBs produce pulses in the radio part of the electromagnetic spectrum that last just a few thousandths of a second but produce as much energy as the sun does in a year. They are believed to originate within magnetars, a kind of ultra-dense neutron star (itself the collapsed remnants of a star) with an exceptionally strong magnetic fields which can warp their behaviour; however, this has yet to be confirmed.

Most FRBs have been detected originate in galaxies other than our own, and are very mixed in nature. Some FRBs emit energy just once but others can do so in repeated bursts. The thinking is that their intense bursts of energy is the result of some complex interaction between a magnetar’s massive magnetic field – trillions of times more powerful than Earth’s – and the outer layers of the neutron star itself, causing a massive explosion we later detect as radio waves.

One FRB that is known to recurring bursts is called FRB 121102, and is located in a dwarf galaxy 3 billion light-years from Earth. It was selected as a candidate for study using China’s  massive Five-hundred-metre Aperture Spherical radio Telescope (FAST), which only became operational in 2020. The hope was study of FRB 121102 would reveal the secrets of these strange objects, including their source and cause. Instead, the study has actually deepened the mystery.

The Five-hundred-metre Aperture Spherical radio Telescope (FAST) in China, the world’s largest (2.25 times larger than the former Arecibo Observatory radio telescope) and most sensitive radio telescope and nicknamed “Heaven’s Eye”

Prior to FAST turning its attention on FRB 121102, recorded observations by the likes of (the now defunct) Arecibo radio telescope suggested it gave off bursts of 10 radio pulses on a non-regular basis. However, FAST is so sensitive, found FRB 121102 can generate up to 117 pulses per hour, with some just a few thousandths of a second apart, with 1,652 bursts detected in the first 60 hours of observations!

Exactly how it can do this remains a mystery – but it suggests that the current theory of magnet field / star “surface” interactions is incorrect. Such interactions would generate violent outbursts of matter from the magnetar, and these would have to collapse to prevent them interfering with further bursts – and a few thousands of a second is too short a period in which this could happen.

No direct conclusions can be drawn from the study of FRB 121102; the international team behind it stating they now need to use FAST to study other repeating FRBs to see if they can find similar “hidden” bursts from them, in order that a more complete picture might start to be built up as to what might be happening, why, and how.

 The “‘Fridge” That Skimmed Earth

I’ve often written about NEOs, or near-Earth objects – chunks of rock in a range of sizes from just a few metres through to a few kilometres  – that orbit the Sun in a manner that means that periodically cross Earth’s orbit or can pass relatively close to us. Such is the threat posed by these objects should one of the large ones actually collide with Earth, considerable effort has been put into finding and tracking them, using their close passages to Earth to better track and predict their orbits in years to come.

As a result, many of the large NEOs have indeed been located and tracked; but there are still many hundreds, if not thousands, which, while not threatening all of civilisation on the planet, could still do much to totally ruin people’s day were they to enter the Earth’s atmosphere and explode under air pressure or even survive and strike a centre of population.

October 24th, 2021 saw a small reminder of this threat, when a chunk of rock about the size of a refrigerator and dubbed Asteroid 2021 UA1, skimmed past Earth, passing just 3,000 km above Antarctica. While the rock was too small to cause any real damage, had it entered the atmosphere, it would likely have completely burned up, it was not actually spotted until it was moving away from Earth once more, its approach having been lost in the glare of the Sun – hence why it acted as a reminder of the threat poised by larger NEOs – that we might not actually see them before them become a problem.

This is what happened in 2013, when a cometary fragment roughly 20 m across entered the Earth’s atmosphere to explode at an altitude of 26 km over the the Russian oblast of  Chelyabinsk. The blast yield of explosion was 400–500 kilotons of TNT, with the shockwave it generated damaging some 7,200 buildings in six cities across the region and injuring more than 1,500 people.

The passage of Asteroid 2021 UA1 is also a timely reminder that later in November, NASA plans to launch the Double Asteroid Redirection Test (DART), an attempt to test a method for diverting asteroids by hitting them with high-speed remote-controlled vehicles, and I’ll have more of that mission in an upcoming Space Sunday report.

Selected Round-Up

Hubble Remains in Safe Mode

As I noted in my last Space Sunday update, the veritable Hubble Space Telescope (HST) entered a “safe” mode intended to protect its science capabilities on October 25th, 2021. With science activities suspended, the instruments are said to be in “good health”. However, in providing an update to the situation, NASA revealed HST actually suffered two glitches in relatively short order.

The Hubble Space Telescope, seen in 2002. Credit: NASA

On October 23rd, the telescope’s science instruments issued an error code indicating the loss of an automated synchronisation message issued by the main computer to provide timing information to the science instruments, allowing them to properly respond to commands. This issue appeared to be corrected when a command was sent to the science instruments ordering them to reset; however, the October 25th issue appears to be related, in that “multiple losses of synchronisation messages” were reported immediately prior to the safe mode being triggered.

Right now, Hubble engineers have no idea what triggered the loss of the messages, and the focus is on trying to obtain further data from HST so a more proper diagnosis of what occurred, and what is required to bring Hubble back on-line.

Blue Origin Lose Moon Lander Case But Roll-Out New Glenn Pathfinder

In April, NASA announced that it had selected SpaceX to develop the initial Artemis Human Landing System (HLS) to carry crews between lunar orbit and the surface of the Moon, ignoring proposals from teams led by Dynetics and by Blue Origin. The decision didn’t go down well with the latter, both of whom lodged protests with US Government Accountability Office (GAO) to force NASA to change its mind – without success, the GAO upholding NASA’s decision.

But while Dynetics decided to accept the GAO decision and look towards future opportunities to participate in Project Artemis, Blue Origin decided to take NASA to federal court, prompting Elon Musk to tweet, “You can’t sue your way to the Moon!” And it appears the judge reviewing the case agrees.

On November 4th, and while his full findings remain sealed until November 18th, Federal Appeals Judge Richard A. Hertling issued a one-page summary dismissing the Blue Origin case and clearing NASA and SpaceX resume HLS development. Ironically, in the interim, Congress has directed NASA to offer a second contract for HLS development, something the agency, in responding to the judge’s summation, has indicated it will do.

Just ahead of the summation being published, on November 3rd, Blue Origin finally rolled out the pathfinder first stage of their New Glenn heavy lift launch vehicle.

The New Glenn pathfinder first stage is rolled out on November 3rd. Note the upper guidance fins that will help “steer” the stage as it drops back towards Earth, post-launch. Two larger fins can be seen towards the base of the stage as well. Credit: John Van Horne

It’s the first time a first stage of the rocket – now running some 2-3 years behind schedule – has been seen outside the company’s fabrication facilities;. But this stage is not flight capable, but a structural test article. In this regard, the stage is intended to be used to test and refine launch ground support operations, such as moving a New Glenn stage around and later, possibly, for stress testing the stage itself.

The 7m diameter 58-metre long first stage is designed to be re-usable, as will its still-to be built upper stage, called Jarvis. After separation following launch, the first stage land some 1,000 km down-range from its launch site, using a converted deep-water cargo ship as its landing platform. Currently, New Glenn is not expected to make its maiden flight before the last quarter of 2022 at the earliest.

Virgin Orbit and Japan’s ANA Team-UP

Virgin Orbit, the air-launch company founded by Sir Richard Branson, has announced a non-binding agreement with Japan’s All Nippon Airlines (ANA) to carry out up to 20 launches of its small satellite rocket out of an airport in Japan’s Oita Prefecture.

Under the agreement – which is subject to US Government approval, Virgin Orbit being a US-registered company – ANA and several partners will provide ground support facilities for LauncherOne and its 747 carrier / launch aircraft, and act as co-ordinator for securing the 20 launch payloads envisioned by the agreement.

Virgin Orbit could commence launch operations out of Japan as early as 2023 with the assistance of ANA. Credit: Virgin Orbit

If the US approves the agreement, the airport within Oita will give Virgin a Second base of operations in the Pacific – earlier this year the company indicated it plans to operate out of the US territory of Guam. In addition, ANA has indicated they could have the required mobile facilities required of launch operations in place by the end of 2022, ready for launches to commence in 2023, subject to orders.

Crew 3 Launch and Crew 2 Return Both Delayed

The NASA / SpaceX Crew 3 mission to the International Space Station (ISS) has been further delayed due to continuing bad weather issues.

The vehicle, carrying four astronauts to the ISS, had been due for an October 31st launch, but weather concerns along its line of flight caused the it to be pushed back to Wednesday, November 3rd. Then an unspecified “minor medical issue” experienced by one of the four crew forced the launch to be delayed until Saturday November 6th, 2021, only for weather to again cause the launch date to be set for no earlier than Monday, November 8th.

The Crew 3 astronauts (l to r): Europe’s Matthias Maurer, and NASA astronauts Thomas Marshburn, Raja Chari and Kayla Barron. Credit: NASA

When it does launch, the mission will see the maiden flight of the third Crew Dragon to be constructed. Christened Endurance, it joins Endeavour – the first Crew Dragon to fly with astronauts aboard during the Demo 2 flight -, and Resilience, which most recently flew the Inspiration4 orbital flight, with one more vehicle due to also support ISS and other Dragon operations.

Monday, November 8th is now also the date set for the return of Crew 2 from the ISS aboard Crew Dragon Endeavour. Originally, it had been hoped Crew 3 would arrive at the space ahead of a Crew 2 departure, to allow for a formal hand-over of duties. However, with the Crew 3 launch getting pushed back, this seemed increasingly unlikely. Now, thanks to the weather, it appears the two crews will be making their respective ways to / from the station on the same day, and the handover will be indirect.

China: of  Hypersonic Test Flights and Space Debris Mitigation Exercises

In October, the Financial Times reported that China launched a nuclear-capable hypersonic weapon atop a rocket during an August test. Whether or not it was a weapon is debatable, but that didn’t stop the American Right getting its knickers in a twist and blaming President Biden and his “woke” policies for America being caught “unawares” – this despite the fact the Pentagon has known about China’s development of a hypersonic missile system since 2014 (indeed, the DZ-17 is actually referenced by Wikipedia as being “operational” since 2019).

The finger-pointing was also somewhat silly, given the news broke a month after the US had completed successful test flights of its own hypersonic missile systems. As it is, the Chinese have said the August launch was actually that of a scale model of a planned space plane – something they are also believed to be developing.

More recently, the Right is again wibbling over two other Chinese launches. The first was on October 24th, when a Long March 3B rocket placed the Shijian 21 satellite in a geosynchronous transfer orbit, where it has now been joined by a second object flying relatively close to it.

The “secret” launch of Shijian 21, as seen in a photograph released to the media by the China Aerospace Science and Technology Corp. (CASC)

This has led to claims that China is developing some kind of “satellite killer” capability, with the “secretive” nature of both launches being pointed to as evidence. However, the vast majority of Chinese launches are “secretive”, in that they tend to only be announced after the fact – as was the case with the Shijian 21 launch. Nor was the launch entirely “secretive”; China had announced they would be carrying out “space debris mitigation” tests before the Long March lifted off, and then confirmed the launch was part of that test immediately following the launch.

“Space debris mitigation” is a fancy term for finding a way to get rid of the more dangerous elements of space junk orbiting the Earth (such as the estimated 3,000 decommissioned satellites). Some of this represents a serious risk to orbital space stations – such as the one China is building, thus giving them a reason to develop the means to dispose of some of that junk.

To do this, however, they need a suitable piece of “target” junk: and this is exactly what the November 3rd launch appears to have been. After tracking the launch, 18th Space Control Squadron (SPCS) of the US Space Force identified the object that has joined Shijian 21 as a apogee kick motor (AKM), a small motor usually employed to push satellites from an initial low Earth orbit to their intended operational orbit. Such motors often become orbital debris once they have done their job and are detached from the satellites they had been assisting. As such, the AKM now in close proximity to the Chinese satellite appears to be an ideal target for any “space debris mitigation” exercise.