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.

SN8 Passes Pre-Flight Tests

The next SpaceX Starship prototype, SN8 successfully completed several of its pre-flight tests during the week.

On Sunday, October 4th, the lower hull section of SN8 underwent a pressurisation when its tanks were filled with inert nitrogen gas in a basic leak test. This was followed during the week by three further tests using super cold liquid nitrogen to simulate the temperatures the tanks will experience when loaded with fuel. The first test was simply a temperature test, while the second used a hydraulic ram pressed up against the base of the vehicle to simulate the thrust of three Raptor engines pushing up against the vehicle. This revealed a minor leak at the engine mounts which took two further tests to fully eliminate, the vehicle finally passing a full test on Friday, October 9th, that the vehicle passed a full test.

As excess liquid nitrogen is vented, the skin of starship prototype SN8 shows frost-build-up as the extreme cold of the liquid in its oxygen tank (lower area and methane tank (upper frost ring) is transmitted to the vehicle’s surface during the Friday, October 9th cryo test. Credit: Mary, Bocachicagal.

The next steps for SN8 will be the mounting of its 3 Raptor engines that will power it on its 16 km altitude flight, before at least one static firing test of the motors in readiness for that flight. However, it’s not clear whether the engines will be mounted and tested before or after the upper sections of the vehicle, including the forward aerodynamic canards, are mounted on it.

Russia Announces Move to Reusability

In  what is seen as a direct take on SpaceX and Blue Origin the Russian space agency, Roscosmos has announced the development of its own reusable launch vehicle.

The Amur rocket is expected to cost some US $880 million to develop, and offer a payload delivery of up to 10.5 tonnes to low-Earth orbit at around US $22 million per launch. The vehicle will be propelled by a mixture of liquid oxygen and liquid methane – the fuel stocks SpaceX and Blue Origin will be using in the likes of the Super Heavy / Starship combination and the New Glenn launcher.

Conceptual images for the Russian Amur launch vehicle bear striking similarities to the SpaceX Falcon 9 with the landing legs and attitude vanes. Credit: Roscosmos

The payload capacity places Amur as a direct replacement for the Soyuz 2 expendable booster, and its overall design – albeit conceptual at this point in time – places it squarely in the uncanny valley of a SpaceX Falcon 9 booster (although the latter already has a greater payload capacity and broader range of flight envelopes). The first Amur is expected to launch in 2026, with first stage of the vehicle intended to be reusable.

After Mars, UAE aims for the Moon

Following the successful launch of its Hope Mars satellite earlier this year, the United Arab Emirates has announced it is not going to be left out of efforts to further explore the Moon.

In  particular, the country plans the send a small robot rover to the Moon in 2024. However, unlike America, China and others who are firmly focused on the south polar regions of the lunar surface,  this rover – called Rashid – will go to one of the nearside equatorial regions that have yet to be explored in detail.

UAE’s planned Rashid lunar rover. Credit: MBRSC)

Once there, the 4-wheeled, solar-powered rover will spend 14 days (a lunar “day”) studying the solar wind and how it interacts with the lunar surface, examining the lunar regolith (surface material / dust), and monitoring experimental space suit materials affixed to its hull to determine how they withstand the lunar environment (a similar study is being carried aboard NASA’s Perseverance rover en route to Mars).

Whilst designed for a 14-day mission, it is hoped that circuitry on the rover will allow it to regulate battery power consumption whilst hibernating during the 14-day lunar night, so that it will be able to “wake up” and resume operations with the return of sunlight at its location.

No launch partner for the mission has been announced – the UAE does not have its own launch capability  – although given their working relationship with the Hope launch, Japan would seem to be a likely partner for this mission.

China Confirms Lunar “Super Booster” and Reveals 18 New Tiakonauts

China has confirmed it is working to develop a new human-rated launch vehicle that amounts to being – by comparison to their current family of launch vehicles – a “super booster”.

Currently unnamed but referred to as the “921 rocket”, the new rocket has been hinted at since around mid-2018, but it was only at the end of September that the Chinese officially confirmed it was under development, and has the primary goal of delivering up to 25 tonnes to lunar orbit.

The new Chinese rocket was first seen in model form at the 2018 China Space Conference in September 2018, and confirmed at the same conference in 2020. Credit: CASC

The system is being developed by the China Academy of Launch Vehicle Technology (CALT). It will comprise a central core vehicle of 4 metres diameter with three stages, flanked by two large strap-on booster units also of 5-metre diameter, giving the vehicle a very similar appearance to America’s Delta IV Heavy and Falcon Heavy rockets, although at 87 metres in height, it will be taller than both. It is expected to work specifically with China’s next generation of crewed capsule vehicles. Both the core stage and strap-on boosters will utilise an updated version of China’s YF-100 motor.

This new crew vehicle first flew on an uncrewed test in May 2020. It has two variants, both modelled on a 6-person capsule, with one using a small-scale service module designed to provide power and propulsion during operations in Earth orbit, and a large service module intended for flights to the Moon and back – among other mission profiles. Once operational, the vehicle will replace China’s Soyuz-derived Shenzhou capsule system.

The 1two variants of China’s new crew vehicle as drawn by the Beijing Institute of Space Mechanics and Electronics (although the vehicle has a more conical capsule than shown here). First flown in an uncrewed mode in May 2020, the craft will be used in conjunction with China’s new rocket, Credit: Beijing Institute of Space Mechanics and Electronics

No potential launch date has been given for the new rocket, while details of China’s plans to send crews to the Moon remain sketchy. Officials only note that the rocket has to be built and tested, and lunar missions are dependent on the development of a vehicle capable of landing a crew to the lunar surface and returning them safely to orbit.

In further support of its human spaceflight ambitions, China also revealed its new intake of taikonauts who will fly to, and operate, the country’s upcoming space station.

The 18  – 17 men and one woman – are largely split between those from Chinas military and those from science and engineering backgrounds related to space exploration (7 apiece), the remaining four have been designated “mission payload specialists” who will be trained for specific operating aspects of missions, rather than being more generalist, as with the other 14. Together, they almost double the number of active astronauts in China’s human space programme.