Space Sunday: a Dragon, a telescope and a heavenly princess

Sunday, November 15th, 2020, 19:27 local the Crew-1 Falcon 9 booster lifts-off from Kennedy Space Centre’s Pad 39A.Credit: NASA

Sunday, November 15th saw the official start of a new era in low-Earth orbit space transportation with the launch of the NASA / SpaceX Crew-1 mission to the International Space.

Originally scheduled for launch on Saturday, November 14th, the Crew-1 mission was delayed due to weather causing concerns about the recovery of the Falcon 9 launch vehicle’s first stage. However, at 19:27 local time on Sunday (00:27 GMT on Monday, November 16th), the Falcon 9 topped by the Crew Dragon and its crew of four – NASA astronauts, Mike Hopkins, Victor Glover, Shannon Walker and Japanese astronaut Soichi Noguchi – lifted off from the SpaceX leased Pad 39A at Kennedy Space Centre, the first stage of the rocket making a successful return to Earth and landing aboard the autonomous drone ship Just Read The Instructions.

Resilience approaches the ISS on November 16th/17th 2020. Credit: NASA / SpaceX

Nine minutes after launch, the Crew Dragon capsule – named Resilience by the crew – achieved an initial orbit, and the crew followed a long tradition of space flight dating back to the first manned space mission, and revealed their “zero gee indicator”, a Baby Yoda plushy toy from the TV series, The Maldorian.

The use of toys and dolls as such indicators goes back to the flight of Yuri Gagarin and his flight aboard Vostok-1 in April 1961.  Gagarin carried a small doll into orbit out of curiosity, as he wanted to see what floating in the micro-gravity of space looked like. However, his practice was copied by other Soviet cosmonauts, and in turn by NASA missions, with crews on the Crew Dragon continuing the tradition – Doug Hurley and Bob Behnken carried a plushy planet Earth on their trip to the ISS earlier in  2020 during the Crew Dragon certification flight.

While not confirmed, it is believed the selection of Baby Yoda was due to back-up crew member Kjell Lindgren. A long-time Star Wars fan, Lindgren had used a model of R2D2 as a zero-gee indicator during a 2015 Soyuz flight to the ISS and while aboard the station, persuaded the rest of the crew to dress up as Jedi Knights for a special NASA promotional poster.

It’s been a tough year. And the fact that … SpaceX and NASA were able to get our spacecraft ready to go, the rocket ready to go, throughout this year, throughout the pandemic, and all of that — we were inspired by everybody’s effort to do that. So that’s why we named Resilience, and we hope that it puts a smile on people’s faces, it brings hope to them. Baby Yoda does the same thing. I think everybody, when you see him, it’s hard not to smile, and so it just seemed appropriate.

– Mission commander Mike Hopkins explaining the choice of name for the Dragon
capsule and the selection of Baby Yoda as the zero-gee indicator.

A NASA graphic showing the craft docked at the ISS at the time the Resilience docked. Credit: NASA

It  took some 27 hours for Resilience to catch up with the ISS, finally rendezvousing and docking with the station at 11:01 EST on Monday, November 16th (04:01 GMT, November 17th). Following a further 2 hours of post-flight checks and preparations both in the capsule and on the station, the forward hatch on Resilience was opened and the four crew were invited aboard the ISS. In doing so, they set a new record for the space station: the first time it has been occupied by full-time crew  totalling seven  people. This is actually one more person than the ISS is designed to accommodate, so Crew-1 commander Mike Hopkins is sleeping aboard the Resilience.

The Expedition 64  crew will remain on the ISS for a 6-month rotation period, Hopkins and his crew joining NASA astronaut Kate Rubins and Russian cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov, who arrived at the ISS on October 14th, aboard the Soyuz MS-17 – a mission which was itself a record-setter, rendezvousing with the station just three hours after launch, utilising Russia’s “ultrafast” ISS launch and rendezvous flight plan for the first time.

Kate Robins, who arrived aboard ISS as a part of the Soyuz TM-17 crews, greets Victor Glover as he boards the ISS from Resilience, marking the first time an African-American astronauts has boarded the station as part of the full duration crew. Credit: NASA
Once aboard the station, the crew wasted little time in getting down to work. On November 18th, Ryzhikov – currently in overall command of the ISS – and Kud-Sverchkov made a 6-hour 48-minute spacewalk that inaugurated the operational use of the Poisk “mini research” module as an airlock.

As I noted in my previous Space Sunday update, Poisk has been delivered as an airlock / docking module in 2009. It is one of two such units attached to the Russian Zvezda module, the other being the Pirs airlock / dock, deployed to the ISS in 2001. Up until the Ryzhikov / Kud-Sverchkov EVA, Poisk had only been used as a docking module, spacewalks generally being conducted via the Pirs module.

 Sergey Ryzhikov (centre top with the red stripe on his backpack) and Sergey Kud-Sverchkov work outside of the Poisk (the vertical unit) and Zvezda modules of the ISS. Credit: Roscomos

However, Pirs is due to be removed from the ISS in 2021, so it can be de-orbited to burn up in the upper atmosphere using one of the Russian Progress resupply vehicles. It is due to be replaced by the Nauka Multipurpose Laboratory Module (MLM) – although there are some doubts about this module, as its launch has been delayed so much, several of its systems are at the end of their warranty period.

In  particular, the Poisk spacewalk was to start the process of decommissioning Pirs, by moving vital communication equipment and cabling from that module and connecting them to Poisk, allowing it to become the primary Russian EVA airlock.  As  well as this work, Ryzhikov and Kud-Sverchkov retrieved hardware used to measure space debris impacts, and repositioned an instrument used to measure the residue from thruster firings. The EVA marked the 47th Russian space walk in support of ISS operations, and the 232nd ISS spacewalk overall.

Continue reading “Space Sunday: a Dragon, a telescope and a heavenly princess”

Space Sunday: asteroid sampling & starship building

Kissing an asteroid: the sample head of TAGSAM, the sample gathering mechanism on NASA’s OSIRIS-REx makes contact with asteroid Bennu on October 20th, 2020. Credit: NASA

In my previous Space Sunday update, I covered the (then) upcoming attempt by NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) to snag samples of material from the surface of asteroid 101955 Bennu, a carbonaceous near-Earth asteroid.

The attempt was successfully made on Tuesday, October 20th – although just how successful it was did not become apparent until a few days later, when mission engineers realised they now had a slight problem.

The mission required OSIRIS-REx slowly descended from its close-in altitude of 770m, a sample gathering called TAGSAM (Touch-And-Go Sample Acquisition Mechanism) extended beneath it. This was intended to make very brief contact with the surface of Bennu, absorbing the spacecraft’s momentum in springs, and allowing it to fire a nitrogen jet to blast material up from the asteroid some of which would hopefully be caught in the arm’s sampler head, prior to the arm “pushing off” from Bennu once more, allowing OSIRIS-REx to gently back away to a point where it could examine what it has gathered.

OSIRIS-REx: the sample-gathering operation. Credit: NASA

The entire operation was scheduled to take some 4.5 hours from start to back-away and parking. The event was live-streamed, but due to the current distance between Earth and Bennu, those on Earth were witnessing events 18.5 minutes after they had actually occurred. This also meant the entire operation was carried out autonomously, the software controlling it having been previously uploaded to the satellite.

OSIRIS-REx, following Bennu’s rotation about its axis, struck the asteroid a metre one metre away from its intended contact point, which lay within a shallow crater on Bennu that has been christened “Nightingale”. It remained in contact with the surface for 6 seconds – very slightly longer than had been anticipated.

The moment of contact for TAGSAM – and of actually smashing through the surface material on Bennu (film speeded up). Credit: NASA

Whilst there was a camera on the robot arm recording the operation, the footage could not immediately be sent back to Earth. Instead, mission controllers relied on the telemetry OSIRIS-REx did immediately transmit back to Earth. This revealed that everything had apparently gone as planned: TAGSAM made contact, the gas was fired and regolith (surface material blasted upwards. The telemetry then confirmed OSIRSIS-REx was backing away from the asteroid towards the point where analysis of the amount of captured material could be carried out.

This was transcendental. I can’t believe we actually pulled this off. The spacecraft did everything it was supposed to do. Even though we have some work ahead of us to determine the outcome of the event, this was a major accomplishment for the team. I look forward to analysing the data to determine the mass of sample collected.

– OSIRIS-REx Principal Investigator Dante Lauretta

Then came the first of the surprises.  When the video footage captured by the TAGSAM arm camera was received and processed (above right) on October 21st, it revealed that the sample head hadn’t so much touched the surface of Bennu as smashed straight through it to an estimated depth of almost 50 centimetres – and in doing so, had pulverized a rock roughly 20 cm across which, when first viewed in the footage, caused the mission team to worry it might prevent sample gathering and damage the sample head.

The next step in the operation was to analyse the state of the sample head once TAGSAM had been returned to its stowed position against the spacecraft. To do this, one of the star tracker cameras used for navigation was tasked to capture an image of the sample head. When this was returned to Earth, mission staff had a second surprise: the sample head was “leaking” material.

Following the sample gathering operation, a Mylar diaphragm should have rotated over the opening of the sample head to seal any material gathered inside it – but the star tracker camera revealed this had failed to sit correctly, and a small cloud of material was forming around the sample head as it persistently “leaked” out. Given the force of the contact with Bennu, the mission team realised that, rather than just collecting 60 grams of material, the sample head had likely been filled to capacity, preventing the Mylar cover from correctly sealing it.

A small but growing cloud of material gathers around the TAGSAM sample head on OSIRIS-REx following a sample gathering operation that likely overfilled the sample containment area, preventing a Mylar diaphragm (the white semi-circle, visible in the middle of the circular sample head) from sealing the cavity. Credit: NASA

With material slowly but steadily escaping, the decision was been taken to cancel the attempt to estimate the amount of material gathered, and instead move to transferring the sample head to the Sample-Return Capsule (SAC). This is the unit that will return the sample to Earth when OSIRIS-REx return here in 2023. As the SAC is sealable, moving the sample head there as soon as possible – in this case, October 27th – will ensure the remaining material from Bennu is preserved.

In the meantime, and while OSIRIS-REx cannot start on its return to Earth until March 2021, the decision has been made not to return the vehicle to a low-level “hover” orbiting Bennu, but to instead allowing it to continue away from the asteroid at around 44 metres per hour until it reaches a more extended orbital position.

Continue reading “Space Sunday: asteroid sampling & starship building”

Space Sunday: OSIRSIS-REx: sampling an asteroid

An artist’s impression of NASA’s OSIRIS-REx above the asteroid Bennu,with Earth added in the background for dramatic effect. Credit: NASA Goddard

After a period of delay, NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) is due to attempt the collection of a 60 gram (2.1 oz) sample from the surface of 101955 Bennu, a carbonaceous near-Earth asteroid, on Tuesday, October 20th.

Originally scheduled for August 2020, the attempt to gather the sample requires the space craft to slowly descend to within “touching” distance of the asteroid using a robotic arm. If successful, the sample gathering will open the door for OSISRIS-REx to complete the remainder of its mission before making its way back to Earth where the sample can be analysed.

Launched in September 2016, OSIRIS-REx is one of two such asteroid sample return missions currently in progress, the other being Japan’s Haybusha 2 mission (the original Hayabusha mission also returned samples from an asteroid – but they only amounted to around 1 milligram of material).

Having been launched well ahead of OSIRIS-REx, Hayabusha 2 is actually on its way back to Earth from asteroid 162173 Ryugu, with which it rendezvoused in June 2018. It spent 18 months surveying the asteroid, depositing four micro-rovers on its surface before gathering samples blown off of the asteroid by the force of a kinetic impactor (think bullet), allowing it to collect a mix of surface and sub-surface material. Currently, Hayabusha 2 will deliver its cargo back to Earth during a fly-by on December 6th, 2020, after which it may be tasked with a further sample return mission.

Image sequence showing the rotation of Bennu, captured by OSIRIS-REx at a distance of around 80 km. Credit: NASA Goddard

OSIRIS-REx reached it’s target, Bennu, at the very end of December 2018 and has spent most of the intervening time studying the asteroid in detail. Both Bennu and Ryugu are of interest to scientists for a number of reasons: they are both part of a class of asteroids that are believed to have been around since the formation of the solar system, and so they could help us learn more about that period.

Both are also in the Apollo asteroid group, meaning they routinely cross Earth’s orbit, and thus present a potential collision risk, and at 1 km diameter for Ryugu and just under 1/2 a km for Bennu, an impact from either would not be a Good Thing for Earth. So, another reason for sampling them is to determine their composition (and by extension, allow us to draw conclusions about the composition of other large Apollo asteroids) that may help make a determination of how to deal with them should that threat of impact become real (in fact, there is a chance that Bennu in particular might impact Earth between 2175 and 2199).

Finally, samples from both might offer clues as to how life-forming materials reached the surface of Earth.

Bennu has proven particularly intriguing for scientists. For one thing, it has proven to be entirely unlike anything that had been anticipated; rather than being relative smooth, with crater pits and sand-like regolith (surface material), Bennu revealed it is a boulder-strewn place with rocks in places comparable to mountains relative to its size, many of them placed so closely together, any attempt to gather samples near them would like result in a loss of the vehicle. This required a more extensive survey to determine potential sample sites, with five initially being identified, before these were narrowed to two, the primary, Nightingale, and a back-up.

This image, captured by OSIRIS-REx shows the Nightingale sample gathering crater surrounded by large boulders. The silhouette of the spacecraft (which is about the size of a van – excluding the solar panels and has a mass of just over 2 tonnes) added for comparison. Credit: NASA Goddard

The asteroid also demonstrated it can emit plumes of material from within itself when in the “warm” part of its 1.2 year orbit around the Sun. However, one of the most surprising discoveries was the identification of six bright boulders on the asteroid’s surface which, when subjected to spectroscopic analysis, revealed themselves to be of the same materials as boulders on Vesta, the second-largest asteroid in the solar system, surveyed by the NASA / ESA Dawn mission.

It’s believed that the presence of these rocks indicates that Bennu started life as part of a larger body – an asteroid or planetesimal – within the asteroid belt beyond Mars, where it was in collision with a fragment of Vesta, depositing material from the latter on its surface. That event, or another similar collision, led to a “catastrophic disruption” within Bennu’s parent, creating Bennu itself and sending it on its way into the inner solar system to be caught in an orbit much closer to the Sun.

The asteroid has also revealed itself to be particularly rich in carbon-bearing material, which can tell us how much water it may have contained (and how much might still be present as sub-surface ice). What is particularly interesting here is that many of the boulders on Bennu contain mineral veins composed of carbonate – which on Earth often precipitates from hydrothermal systems that contain both water and carbon dioxide. Some of these rocks are located around the Nightingale sample  recovery area. The presence of such carbonate strongly suggests that Bennu’s parent body, whether asteroid or small planetary body,was likely hydrothermally active. This has in turn given rise to the prospect that any sample returned by OSIRIS-REx might contain organic material.

Continue reading “Space Sunday: OSIRSIS-REx: sampling an asteroid”

Space Sunday: flares and flights

Solar flares and coronal mass ejections have the potential to be massively disruptive, but fortunately, the Sun is of a nature that they are unlikely to be directly harmful to life on Earth on their own. Credit: NASA

As I noted a couple of weeks prior to this article (see: Space Sunday: 3D printed rockets; pi for a planet and solar cycles), our Sun is now entering its 25th (in terms of when formal record-keeping began) cycle of activity. Over the next few years it will become increasingly active with sun spot, flares and their associated events, reaching a peak in about 2025/26, before things once again start to settle down in the second half of this 11-year cycle.

Such events have the potential to interfere with modern life on Earth, particularly in disruption electronic and electrical systems, and present a very real radiation threat to astronauts. Fortunately, however, the Sun is mild-aged and so even its wilder outbursts are not now as bad as they could be, and a number of factors have to line up in order for them to directly affect us on this planet (as happened with the Carrington Event of 1859). Which is not to say we’re entirely safe: the Sun could decide to throw a particularly violent tantrum when Earth happens to be in (for us) the wrong place.

Solar activity is important, as it offers insight for the potential for life forming on other worlds. Take M-class red dwarf stars, for example. They are the most populous class of star in the galaxy, and many have been found to harbour planets (the TRAPPIST-1 system being the most famous) some of which occupying the so-called habitable zone around these stars that should make them good candidates for harbouring life.

It has been known for some time that solar flares can impact the atmospheres of exoplanets, as shown in this ESA video. The new study shows they can do much more

However, such is their size, M-class stars can host solar eruptions that can be 10,000 times more violent that the “average” solar event (flare + coronal mass ejection, or CME) experienced by the Sun and because of the convective nature of such small stars, they are more the norm than the exception. As the normal light / heat output from these stars a much lower than the Sun’s, any planets around them must orbit correspondingly close to the star than is the case within our own solar system. This means that they are potentially more prone to being impacted by these massive super flares, up to and including physically ripping away their atmospheres over time, raising the question as to just how this might affect their surface conditions and habitability for life as we know it.

A study of almost 30 of these M-dwarf stars just published in the Astrophysical Journal reveals that overall such super flares extremely limit the potential for anything but the hardiest micro-organism – although their presence early in a star’s life could actually initially help give life on a planet a helping kick-start,

The study used two sources to study the flaring of some 27 M-dwarf stars: NASA’s TESS “planet hunter” satellite, and the Evryscope Telescope array located at the Cerro Tololo Inter-American Observatory in Chile and operated UNC-Chapel Hill, North Carolina, USA. Both the telescope array and TESS were tasked with observing the candidate stars at the same time, allowing any flare activity on them to be simultaneously recorded.

Solar flares can be accompanied by coronal mass ejections (CMEs) that see huge amounts of the sun’s surface ejected into space as plasmas and electro-magnetic radiation that can massively impact planets. In this image, a CME is clearly visible as a disk is used to block out that of the Sun as is it imaged by the ESA / NASA SOHO mission. Credit: ESA / NASA

As a super flare – which could last up to 15 minutes – occurred, measurements were taken every 2 minutes, generating a temperature profile for the flare from start to finish. This revealed a strong, if complicated, correlation between the overall temperature output of a super flare and the amount of deadly ultra-violet radiation it contained. In turn, this allowed the team to conclude that it is extremely likely that planets in close proximity to these stars will receive so much UV radiation, they are unlikely to support the survival all but the hardiest of micro-organism.

The report also notes that in particular, such super flares would likely quickly wreck any protective ozone layer that may form within a planet’s atmosphere, further limiting the development of life – but that conversely, they may initially be required to help impact ozone formation, in order to allow sufficient radiation to reach the surface of a planet in order to power pre-biotic chemistry that in turn may kick-start living processes.

The team behind the study point out that their data is a relatively fine sampling thus far, and more work is needed. They also note that the super flares captured in the study can be classified as “classic” – an event rising to single peak in terms of radiation, temperature, and outburst in a similar manner to our own solar flares – and “complex”: a solar flare that essentially “pulses” with multiple peaks of energy. The cause of these “complex” super flares is unknown, although they appear to be in the majority based on the sample recorded. The fact that they “pulse” with output means that their physical impact on planetary atmospheres is also liable to more complicated than a direct cause / effect correlation seen with “classic” flares.

Even so, the findings open up a new avenue of study for understanding the potential habitability of exoplanets close to M-dwarf stars, and the result have already tended to correlate a 2018 study that suggests the planet found orbiting our nearest stellar neighbour, Proxima Centauri is unlikely to be life-bearing due to it being impacted by similar super flares.

Spaceflight Round-Up

Crew-1 Delayed

NASA Crew-1: Shannon Walker, Victor Glover and Mike Hopkins, and Soichi Noguchi. Credit: NASA

The first operational flight of the SpaceX Crew Dragon to the International space Station has been delayed.

The flight, which will carry a crew of four – NASA astronauts Shannon Walker, Victor Glover and Mike Hopkins, and JAXA astronaut Soichi Noguchi – to the ISS, had been scheduled to lift-off from Kennedy Space Centre on October 31st. However, on October 10th, NASA announced the flight will be held over until at least mid-November.

No formal reason for the delay has been given;  however the scrubbing of a Falcon 9 launch just 2 seconds before lift-off is being seen as a possible cause. That launch, on October 2nd, of a GPS 3 satellite, was aborted due to what Elon Musk, SpaceX CEO described as an “unexpected pressure rise in the turbomachinery gas generator.”  It has yet to be rescheduled.

The first stage units of both that rocket and the one for the Crew-1 flight have never previously flown, so some have theorised the delay to Crew-1 is to give time for SpaceX to evaluate the problem and ensure it is not something endemic to newer Falcon 9 boosters. Certainly, the GPS 3 launch scrub didn’t prevent SpaceX from launching a further batch of its Starlink Internet satellites using a previously-flown Falcon 9 first stage.

Continue reading “Space Sunday: flares and flights”

Space Sunday: supernovas, weird planets and warnings

The crab nebula: the remnants of a supernova that occurred some 6,500 light years from Earth, and was first recorded by Chinese astronomer in 1054. This is a composite picture made up of 24 images captured by the Hubble Space Telescope in December 1999 and early 2000. Credit: NASA / ESA

Life on our planet faces many threats. Cosmically speaking, the three biggest threats life on Earth faces, are solar flares an coronal mass ejections, Earth-crossing asteroids, and locate supernova events – the violent explosions of stars as they die.

Of these three, Earth-crossing asteroids tend to get the most attention, as they are regarded as the most immediate n terms of potential threat and what we can actually do to actually mitigate that threat if we’re given enough warning. Solar activity is a risk, but fortunately, when even at the peak of its cycle, our middle-aged Sun is rarely viciously violent, and when it does get angry, it’s rare that Earth is directly in the path of an lash-out – although as I noted in my previous Space Sunday article, we have recently come close.

Supernovas are also a mixed bag – we certainly can’t stop them, and if one occurs that is sufficiently violent and close enough to us, then we could be in a spot of bother no matter where we are in our orbit around the Sun. If close enough, supernovas of Type 1a or Type II could go so far as to be extinction level events (ELEs). Fortunately, in order to do so, such a supernova would have to occur in a fairly massive star that’s within a few hundred light years of us – and there are precious few of those. And if if one did explode as a supernova, that are all so far away, we’d see them long before we’d feel the effects.

Take Betelgeuse for example, a star that has caused much speculation among some due to its recent behaviour. Even if we witness the light of its supernova explosion tomorrow, it would be another 100,000 years for the “hard” radiation of the explosion’s cosmic rays to reach us.

But what of smaller stars – white dwarfs – that are also given to going out with a supernova bang? There are a couple on our neighbourhood, but they are nowhere near that stage in their lives, nd by the time they are, we’ll pretty much be beyond the distance from them at which they could do us a mischief.

While supernovae – the violent explosions of certain types of large star at the end of their lives – can leave richly colours clouds of gas and material, like the Veil Nebula seen here, some 2,400 light years away (and some of the earliest of which go on to be the birthplaces of new stars), this is not always the case. Some can leave “bubbles” in interstellar space, regions with very little material in them at all. Credit: NASA / ESA

So, does that mean supernova are not a threat? No; leaving ELEs aside, a local supernova could still trigger long-term havoc with things like the Earth’s climate. In  fact, a new study indirectly points to this possibly being the case around 2-3 million years ago, when the Earth was subjected to the effects of a nearby supernova.

The basic evidence for this comes from concentrations of 60Fe, an iron isotope, found in deep ocean sedimentary rock layers called the ferromanganese crusts. What is significant about this is that 60Fe doesn’t naturally occur here, but is a by-product of supernova events, thus leading some to conclude the remnants of such an explosion once washed over us. However, it has also been pointed out that 60Fe can also be synthesised by AGB stars as they approach the end of their lives without ever going supernova, so it is possible the deposits found on the ocean beds were purely the result of distant interaction with one or more AGB stars far back in the time of Earth’s youth.

Because of this ambiguity, a team from the Technical University of Munich gathered several dozen ferromanganese crust samples from four widely separated  locations on the floor of the Pacific ocean and at depths of between 1.6 km and 5.1 km beneath the ocean surface. They subjected all of these samples to extensive analysis to see if they could find traces of other elements that could be tied to either  a supernova or the output of an AGB star. And they were successful, finding concentrations of the manganese isotope 53Mn. This is significant as this isotope doesn’t naturally occur on Earth, nor is it a product of AGB stars – but it is a product of supernova explosions.

Not a slice of chocolate cake but a slice of a sample of the ferromanganese crust layers drawn from the floor of the Pacific Ocean and shown to contain isotopes that were most likely created by a supernova event.Credit: Dominik Koll / Technical University of Munich

Further, the team’s analysis of both the 53Mn and 60Fe concentrations revealed that both are present in similar amounts and the same ratios throughout all of the samples studied. This suggests that both were present in the Earth’s biosphere at the same time, and were deposited on the ocean floor in  similar quantities over the same period of time, again pointing to them having a common origin in a supernova event. What’s more, because 60Fe has a half-live of 2.6 million years before it decays into nickel, said supernova  could not have occurred more than about 2.5 million years ago.

In addition, the concentrations of both isotopes proved sufficient for the team to estimate the like size of the star the caused the supernova: between 11 and 25 times the size of our Sun. That’s of a sufficient size for the supernova to create what’s as called a “bubble” or “cavity” in space:  a  region that appears to be almost completely  devoid of matter. Interestingly, for the last 7-10 million years, our solar system has been travelling through just such a “bubble”, called the Local Cavity. It is believed to have formed as a result of number of supernova events that occurred between 20 and 10 million years ago – which creates an interesting overlap with the idea of a supernova affecting Earth some 2.5 million years ago.

2.5 million years ago also marks the start of the of Pleistocene period, a time of considerable climate change that saw repeated cycle of ice ages that in turn saw dramatic shifts in the flora and fauna, with multiple mini extinction events, This cycle then repeated in the late Pleistocene through early Holocene (11,700 years ago), and the planet started to warm up again, leading to further cycles of extinction (notably those mammals that had developed to level in the cold, like the woolly mammoth).

What triggered that sudden cooling is unknown, but while the Munich study doesn’t point it it directly, it has been shown that severe interference by cosmic rays can cause dramatic shifts in climate, particularly towards the colder extremes. So again, the time link between that ancient supernova evidenced in the ferromanganese crusts of the seabed  and rise of the ice ages of the Pleistocene is interesting.

Climate change during the early Pleistocene period – possibly the result of atmospheric interference by the supernova – may have given rise to the glaciation periods that occurred throughout that time. These in turn spurred the evolution of species such as the woolly mammoth, the European  Cave Lion and woolly rhino (both to the right of the painting above), all of which became extinction as Earth’s climate once ago changed over the late Pleistocene  and into the Holocene, with some extinctions (such as the mammoth) likely accelerated by over-hunting by primitive humans. Image: painting by Mauricio Antón, “What Killed the Woolly Mammoth?”

Starship SN8 Set for Pressure Tests

The core hull of the SpaceX Starship prototype SN8 was moved to the test stand during the pas week to undergo tank pressure tests. Fitted with the aft aerodynamic flaps that will help the vehicle “skydive” through the atmosphere, but sans the upper section, nose cone and forward aerodynamic surfaces, and currently without motors, the core section was due to undergo a pressure test as this article was being written.

Starship prototype SN8 with aft aerodynamic surfaces in their folded configuration sitting on the test stand at the SpaceX Boca Chica facilities. Its flight to 15 km altitude should take place in the next couple of weeks. Credit: RGV Aerial Photography

This test involves the tanks within the section being filled to operating pressures with inert liquid nitrogen. A hydraulic ram under the stand the exerts pressure on the base of the structure to simulate the stresses the three Raptor engines that power the vehicle will place on the structure in order to verify its fitness for flight.

Should this test be successful, SN8 will have the upper sections added, and its engines mounted. It will then go through further tests, including actual fuelling and a static firing of it motors. Once all these tests have been completed, the vehicle will be ready for its 15 km high “hop”, which is likely to take place before the end of the month.

At the same time as SN8 is undergoing its tests, prototype SN9 is also being readied for its first flight.

Continue reading “Space Sunday: supernovas, weird planets and warnings”

Space Sunday: 3D printed rockets; pi for a planet and solar cycles

A time-lapse image of a fuel tank for the Relativity Terran-1 rocket being constructed using 3D printing techniques. Credit: @thesheetztweetz

Not too many years ago, the only organisations that were seen as being able to operate space launch systems were governments, notably the United States, Russia, Japan, China and India, although France has a long track record of launch vehicle development, while  nations like the UK have also dipped a toe or two into the waters.

However, over the last 20 years, we’ve seen a major paradigm shift with launcher development that has seen much of it move away from government-sponsored development and purely into private hands (although actual launch contracts awarded by governments can oft help grease the wheels of commerce for these companies).

The most obvious commercial launch vehicle developers have frequently been mentioned in these pages: SpaceX, Blue Origin, United Launch Alliance, Northrop Grumman, and so on (note I’m deliberately avoiding certain names such as Arianespace, because while they are the oldest commercial launch provider in the world, they don’t actually develop the rockets they launch; and the big boys of Boeing and Lockheed Martin, as outside of their involvement in ULA, they are focused on government-funded launch vehicle development).

However, there are many, smaller commercial companies that are involved in launch vehicle development and operation. Two of the more interesting of these are Rocket Lab, which I have mentioned in these pages in the past, and Relativity Space.

Founded in 2006, Rocket Lab is the mini-me SpaceX of small payload launchers. Established by its current CEO, New Zealander Peter Beck, the company originally operated in Auckland, New Zealand, but now is primarily headquartered in the United States as a US company  (the New Zealand arm being a wholly owned subsidiary).

The Electron rocket with Rocket Labs’ CEO, New Zealander Peter Beck

Rocket Lab operates the Electron Rocket, flying commercial payloads of up to 300 kg to low Earth orbit (LEO) or up to 200 kg to a sun synchronous orbit (SSO). A two-stage vehicle, Electron uses the electric pump-fed Rutherford rocket motor in both stages, making it the first launch system to use an electric pump system to deliver fuel to the engines.

Currently an expendable launch system, Rocket Lab plan to follow in the footsteps of SpaceX and make the first stage of Electron reusable, although they will not be using a propulsive landing system like SpaceX, but will use parachutes / a parafoil. In addition, the company plans to start providing customers with an optional third stage for the vehicle that can provide a “kick” to motor payloads can use to circularise their orbits.

Up until the time of writing, the company has only launched out of a purpose-built facility on the Mahia Peninsula on New Zealand’s North Island, where it has a 30-year licence to launch rockets every 72 hours. To help with this, the facility offers two launch pad complexes; however, the real ability to meet such a high rate of launches (assuming Rocket Lab grows the customer list it needs to warrant such a fast launch rate) is in the rocket fabrication and assembly process.

The extensive use of composites in the fabrication of both the Electron rocket and its motors means that Rocket Lab can fabricate and assemble a launch vehicle every seven days.  Credit: Rocket Lab

Thanks to the high use of composite throughout the Electron and its motors which accounts for around 95% of parts in both, Rocket Lab has been able to develop a fully automated and very flexible fabrication facility that can produce all the composite parts for the single launch vehicle in just 12 hours. This in turn allows the company to assemble and test a new rocket every seven days.

Starting in 2020 – and potentially in the next couple of weeks – Rocket Lab will commence launch operations from the Mid-Atlantic Regional Spaceport, Wallops Island, Virginia, USA (located at the southern end of NASA’s Wallops Flight Facility). Should it go ahead, the UK’s proposed Sutherland Spaceport, Scotland, may also become a base of operations for Rocket Lab, offering launches alongside the UK’s Orbex, a company a small-scale, reusable launcher capable of delivering up to 150 kg to a 500 km SSO.

Through the long grass – an Electron Rocket undergoing static tests at Rocket Lab’s new launch facilities at the Mid-Atlantic Regional Spaceport, Wallops Island, Virginia, USA. Credit: Rocket Lab

As well as the commercial launch capabilities, Rocket Lab has also been developing its own satellite system – Photon – which the company has indicated could also be used as a carrier vehicle for small interplanetary science missions.

In this, CEO Peter Beck has long been a proponent of exploring Venus, and has been contemplating sending a small mission that planet for the last two years – something he believes Rocket Lab could achieve for as little as US $30 million, utilising Electron as the launcher and Photon as the ferry vehicle, delivering a small science probe massing around 37 kg to Venus. With the discovery of phosphine in the planet’s atmosphere (see Space Sunday: phosphine on Venus, test flights and Jupiter), Beck has indicated Rocket Lab may well accelerate these plans.

Rocket Lab has also developed is own satellite – Photon – which it is considering as the carrier for a small science mission to Venus in the wake of the discovery of phosphine in the planet’s atmosphere.  Credit: Rocket Lab

Continue reading “Space Sunday: 3D printed rockets; pi for a planet and solar cycles”