Space Sunday: collisons, rockets, and telescopes

Official poster for the DART mission, a joint NASA-John Hopkins University Applied Physics Laboraroty (JHUAPL) mission. Credit: NASA

Monday, September 26th 2022 will see NASA’s Double Asteroid Redirection Test (DART) reach its primary goal when a small space probe will collide with an asteroid called Dimorphos in an attempt to test a method of planetary defence against near-Earth objects (NEOs) by deflecting their path around the Sun via a kinetic impact.

The risk we face from Earth-crossing NEOs – asteroids and cometary’s fragments that routinely zoom across or graze the Earth’s orbit as they follow their own paths around the Sun – is not insignificant. More that 8,000 of such objects are currently being tracked, and that number is still rising. Such objects range in size from the relatively small to objects like the infamous 99942 Apophis (370m along one axis). which were it to strike Earth, would result in an estimated explosive force equivalent to 1,000 megatons, through to objects large enough to result in possible extinction events.

In 2013, a cometary fragment roughly 20m across entered Earth’s atmpsohere to explode 26km above the the Russian oblast of Chelyabinsk with a force of 400–500 kilotons of TNT. The resulting shockwave damaged some 7,200 buildings and injured over 1,500 people in 6 cities. This image captures the fragment’s path as it burnt up through the denser atmosphere. with the poiint of its explosive destruction marked by a distinctive “mushroom cloud” towards the right-hand end of the trail. Credit: Alex Alishevskikh

Over the years, various means of prevent such an impact have been suggested, with one of the most popular being the use of the kinetic energy from one or more impacts against the threat to alter its orbital track around the Sun so it would miss Earth. It is a popular option because if we get sufficient warning about a threatening object, it should be possible to plan an intercept mission to strike it at a point in its orbit where only a very small deflection in its track would be enough to ensure it misses Earth, allowing smaller, more manageable payloads to be used.

DART is the final incarnation of what started as two independent missions by NASA and the European Space Agency (ESA) to achieve the same goal. These were then combined into a single mission –  AIDA (for Asteroid Impact & Deflection Assessment(, which would have seen ESA launch a observation platform intended to fly to the designated target asteroid and carry out observations and analysis prior to NASA’s DART impactor arriving, and then observing the impact on the latter and the effect it had on the target’s orbit.

However, the ESA element of the mission was cancelled, leaving NASA to push ahead with DART, with the role of observing the impact taken over by Earth-based based observatories and a small payload carried by DART. To compensate, ESA now plans to launch Hera in October 2024, a mission and vehicle that will rendezvous with the target asteroid in 2027 to observe the overall results of the DART mission.

Dimorphos, the target for DART, is actually a relatively small asteroid, some 170m across (but still large enough to result in considerable destruction and loss of life were it to enter Earth’s atmosphere and explode). It has been selected for a combination of reasons, the most pertinent being it is actually the moon of a much larger asteroid, 65803 Didymos (Greek for “twin”), itself a NEO forming part of the Apollo group, and noted as being potentially hazardous to Earth. It is around 780m across, and it orbits the Sun every 770 days, its orbit eccentric enough  for it to cross both the orbits of Earth and Mars, and thus present a potential impact hazard to both.

Dimorphos (Greek: “having two forms” and discovered in 2003, seven years after Didymos was first located) occupies an equatorial and near-circular orbit around Didymos with a period of 11.9 hours. This makes it an attractive target because its position is easy to calculate / track, and the fact that it is orbiting a large object means that the angle of deflection as a result of DART’s impact can be directly measured against its motion around Didymos, and from this it will be possibly to extrapolate the amount of deflection achieved had Dimorphos been a solo asteroid en route to a collision with Earth.

DART launched on November 24th, 2021 atop a Falcon 9 rocket. In order to impact the asteroid at a speed sufficient to affect its velocity, the vehicle has been propelled towards its target by a solar-powered NEXT ion thruster, and will strike Dimorphos head-on at a speed of 6.6 kilometres per second. This should be sufficient to effectively slow it in its orbit around Didymos and result in a charge to the orbital period and shape. Given Dimorphos is large enough to exert some gravitational influence over its parent, it is expected that Didymos’ velocity and orbit will also be affected to a small degree.

An artist’s impression of how the LICIACube cubesat might witness the outflow of ejecta from DART’s impact into Dimorphos. Credit: ESA / Italian Space Agency

Exactly how small or obvious all these changes will be is unknown – we simply do not know the topography of Dimorphos to know where and how DART will strike it. However, to assist with Earth-based observations of the impact, earlier this month DART released the Light Italian CubeSat for Imaging of Asteroids (LICIACube).

Built by the Italian Space Agency, this cubesat is now on a trajectory that will carry it through the Didymos / Dimorphos pairing, allowing it to observe and hopefully record DART’s impact and also gather initial data on the immediate results of the impact – although it is estimated that it will be a week or so before the overall effects of the impact can be properly interpreted. Similar cubesats, originally dubbed “Luke” and “Leia” but now officially called Milani and Juventas (a case of football winning out over Star Wars in the Italian science team?) will accompany the Hera mission in 2024.

DART itself carries little in the way of science instruments related to the mission, other than a 20 cm aperture camera called Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO, which should record and return images of both Didymos and Dimorphos right up to the actual impact). However, it is in many respects also a technology demonstrator, making use of the  Roll Out Solar Array (ROSA) system recently deployed to the International Space Station, and which allows for more efficient harvesting of sunlight over a smaller area of solar array surfaces to generate power, and also RLSA, the spiral Radial Line Slot Array, a new type of compact and lightweight high gain communication antenna.

An artist’s impression of the NASA DART vehicle under propulsive thrust from its ion engine, moments before impacting with the asteroid Dimorphos. Credit: NASA

Currently, DART remains on course for an impact with Dimorphos at 23:14 UTC on Monday, September 26th, 2022. The images returned by the DRACO camera ahead of the impact will mark only the 6th time we have received close-up images of the surface of an asteroid.

Big Boosters: SpaceX Booster 7’s Seven and Artemis 1’s Weather Delay

It’s been a week of ups and downs for the two big boosters which are most prominently on spaceflight enthusiasts’ minds.

At the SpaceX Starbase Facility in Boca Chica, Texas, Booster 7, the vehicle seen as the favourite to lift the company’s massive Starship into the sky on the system’s first orbital attempt, completed a second spin-start test of seven of its 33 Raptor 2 engines  on September 19th. This looked to be a different selection of motors to those tested the previous week, meaning that between 14 and 17 of the booster’s motors have now completed spin-starts. Nor was this the end of things: just a few hours after the spin-start – which lasted around 13 seconds – the booster was re-pressurised with fuel and warning given of a further engine test.

This was a full static fire of seven of the engines, marking the largest number of Raptor 2 motors to go through such a test thus far. Slow-motion payback of high-speed film shot of the event reveals that – as with the spin-start tests – rather than igniting all seven engines simultaneously, engine ignition was staggered, which might be indicative of how actual orbital launches will be managed; staggering engine starts by just a few milliseconds could help with reducing noise vibration resulting from all 33 engines coughing into life at the same time, and may even help reduce the amount of sound being deflected back up against the vehicle and the launch stand.

Following this test, SpaceX announced that, rather than remaining at the orbital launch facility for further engine tests, Booster 7 would be returned to the production centre at Starbase for “robustness upgrades”, and Booster 8 would replace it on the orbital launch mount to undergo its own testing. Whilst not entirely clear from the tweets given, it appears these tests will include a full wet dress rehearsal (WDR), which could involve stacking the booster with Starship 24, then fully tanking them and proceeding through a launch countdown that stops short of engine ignition. Then, after this, there will be a full 33-motor static fire test for a booster.

Whether this means Booster 8 will overtake Booster 7 to become the vehicle to make the first orbital launch attempt with a Starship on top, or whether the two boosters will again be swapped to allow Booster 7 make the attempt – which SpaceX appear to be hoping to make in November (still subject to the granting of an FAA license) – is unclear.

Either way, Booster 7 was removed from the launch mount mid-week, and the launch mount itself then went through a series of tests of its upgraded sound suppression system, which appears to deliver both water and nitrogen as to the flame pit of the launch table to both absorb sound (and reduce the potential for it causing damage to the vehicle or launch facilities) and reduce the risk of unexpected fire.

Booster 8 (centre left) imaged on Highway 4, Boca Chica, on its way to the Starbase test and launch facilities. Just to the right of the booster stands Starship 24, located on a sub-orbital test stand. Centred in the photo is the orbtial launch tower, with the mechazilla lifting arms lowered and rotated away from the launch table and Booster 7 (hidden by the bulk of the launch tower). Credit: NASASpaceflight.com (not a NASA afilliate)
Meanwhile, on September 21st, NASA held a further fuelling test of the massive Space launch System rocket that will launch the uncrewed Artemis 1 mission to cislunar space. Earlier attempts to complete this test – a critical final step in readying the massive launcher for its maiden flight – had to be curtailed due to leaks in the liquid hydrogen fuel feed system at the base of the rocket, leading to padside repairs, as I noted in my previous Space Sunday update.

While the September 21st test also encountered leaks with the liquid hydrogen propellant flow, they were now sufficient to curtail operations, and the tst was successfully completed with both the core and upper stage liquid oxygen and liquid hydrogen tanks being fully fuelled roughly 6 hours after operations commenced.

One September 23rd, and after post-test checks on the vehicle, NASA held a press conference to confirm they would be making a launch attempt on Tuesday, September 27th, 2022 – only to have to call off the attempt on the 24th September due to tropical storm Ian threatening to roll across Florida and over the Space Coast, potentially requiring the vehicle to be rolled back to the safety of the Vehicle Assembly Building (VAB).

The Artemis 1 SLS booster on launch pad 39-B at Kennedy Space Centre. Credit: NASA

At the time of writing, no final decision had been announced regarding the roll-back proceeding. Should it occur, it is likely to occur overnight (local time) on Sunday 25th / Monday 26th September). This roll-back would mean the earliest launch opportunity would be October 2nd; however, this is a date in doubt due to the planned October 3rd launch for the NASA / SpaceX Crew 5 mission to the ISS from neighbouring Pad 39A. As both pads within launch Complex 39 at Kennedy Space Centre use the same infrastructure, back-to-back launches from the two pads are logistically difficult, and was there are further windows for the Artemis 1 launch, letting this slip is seen as preferrable to disrupting ISS operations.

The one good piece of news for Artemis 1, is that the flight termination system (FTS) has received a recertification waiver from the US Space Command at Cape Canaveral Space Centre. The FTS is used to destroy a rocket should it veer off-course post-launch. However, its batteries have a limited service life, and so packages need routine re-certification to state their batteries are suitable for use – or the batteries require replcing. Re-certification  / replacement means returning the vehicle to at VAB, further delaying any launch. However, the USSC has agreed that the package on the SLS could have the recertification delayed until mid-October, allowing the vehicle o be available for the late September / early October launch windows.

JWST Update: Images and Issues

On September 24th, NASA released images of the solar system’s outermost planet, as captured by the James Web Space Telescope. The pictures, taken in July 2022, show not only Neptune’s thin rings, but its faint dust bands, never before observed in the infrared, as well as seven of its 14 known moons.

Neptune, its rings and some of its moons as seen by JWST in July 2022. Credit: NASA

Neptune has fascinated researchers since its discovery in 1846. Located 30 times farther from the Sun than Earth, it is characterised as an ice giant due to the chemical make-up of its interior, whilse because of the great amounts of methane and heavier elements within its atmosphere, it has a disntinctive ocean blue colouring when seen in visible light.

The JWST images capture Neptune in the near-infra-red wavelengths which are readily absorbed by the planet’s atmosphere. This results in it appearing very differently to how it appears in visible light, looking light a misty, crystal marble lit from within by bright streaks – actually the atmospheric interactions only previously hited at b the passge of high-althitude cloud zipping around the planet. Beyond it, and more particularly, the planet’s ring and dust system is revealed in the clearest detail seen in more than 30 years.

Three views of Neptune over the decades, each revealing different information about the planet and its rings. Credit: NASA

Among the seven moons also captured in the JWST images is massive Triton, which appears to float over Neptune like a giant star – the result of the moon reflecting around 70% of the sunlight striking it, thanks to the frozen sheen of condensed nitrogen covering it.

The images of Neptune came at a time when it was confirmed the observatory has developed a minor issue. This lays with a grating wheel mechanism within the Mid-Infrared Instrument (MIRI), resulting in suspension of one of the instrument’s four operating modes (medium-resolution spectroscopy observations).  The other three observing modes — imaging, low-resolution spectroscopy and coronagraphy — are not affected, and observations using those modes of MIRI are continuing.

Naptune and its rings and moons, as omaged by JWST in July 2022. Credit: NASA

The cause of the friction within the mechanism is not clear. Hoever, NASA made it clear the decision to suspend the affected operations with MIRI was not as a result of failure, but rather “an abundance of caution” so that engineers could review telemetry data from the instrument and the mechanism in order to understand the extent of the issue, what might be done to correct it and the potential for impact on mid-range spectroscopy data already gathered by the instrument. In the meantime, mission managers remain confident MIRI will return to full operations in the near future.

Space Sunday: the Sun, Moon and updates

An artist’s impression of a ustaining Lunar Development (SLD) lander heading for the Moon (see below). Credit: NASA

The launch of Artemis 1, provisionally scheduled for September 23rd has been … postponed,  just days after NASA indicated the date was their preferred new target for the uncrewed mission to cislunar space.

As I noted in my previous Space Sunday update, this date and the one following it (September 27th 2022), hinged on a number of factors, including a test of the repaired propellant feed lines on the mobile launch platform which have proven to be the thorn in NASA’s paw when it comes to the first launch of the massive Space Launch System rocket.

This test had been scheduled for Saturday, September 17th. However, it was decided to push it back to the 21st to allow more time for the ground crew to have more time to prepare for the load test. Attention has therefore switched to attempting the launch on September 27th with October 2nd a provisional back-up date. However, the latter remains under review as NASA plan to launch a crew to the International Space Station (ISS) aboard the SpaceX Crew 5 Falcon 9 / Crew Dragon combination from Pad 39A on October 3rd.

Artemis 1 on pad 39B at Kennedy Space Centre: no launch before September 27th, 2022. Credit: NASA/Joel Kowsky

A further potential hurdle for meeting either launch date is the need for the US Space Force to grant a waiver on the recertification of the Flight Termination System (FTS) – the package used to remotely destroy the rocket if it veers off-course during its ascent through the atmosphere. The request for a waiver is still being evaluated at Canaveral Space Force station; if denied, then the rocket will have to be rolled back to the Vehicle Assembly Building (VAB) so the FTS can be fully re-certified – a porcess that is liable to push any launch back until after October 2nd.

The September 27th launch window opens at 15:37 UTC for 70 minutes and presents a “long class” mission for the uncrewed Orion space vehicle, lasting 41 days, with splashdown occurring on November 5th, off the coast of San Diego, California.

NASA Requests Proposals for Additional Lunar Landers

On September 16th, NASA issued a call for proposals for a lunar lander vehicle in support for crewed lunar missions beyond the initial Artemis 3 mission – the first mission to land an American crew on the Moon since 1972’s Apollo 17 mission.

That first mission is due to utilise a modified version of SpaceX’s Starship for place a crew of two on the surface of the Moon and return them to orbit. However, the contract granted to SpaceX – which has yet to actually proceed with work on the modified vehicle in earnest – was viewed as controversial at the time it was given, being granted in the face of two far more capable – if more expensive – proposals. As a result, NASA was ordered by Congress to seek an additional lander vehicle under what is referred to as the Sustaining Lunar Development (SLD) project. Companies interested in responding to the call have until November 15th, 2022 to do so.

The call is for a far more versatile vehicle than that defined by the contract for the initial Human Landing System (HLS) contract awarded to SpaceX. It calls for a lander vehicle type capable of “sortie” style missions with crews of 2 and landing up to 25 days apiece, with the crew living aboard the vehicle. These missions will likely be “scout missions” to evaluate potential sites on the Moon where a base might be established.

The NASA NextStep HLS-SLD includes the development of the lunar gateway station orbiting the Moon and stratgies for carrying technologies developed for lunar operations for use on Mars. Credit: NASA

In addition, and supported by habitat units delivered separately to the lunar surface, the vehicle must be capable of landing crews of 4 astronauts on the Moon for up to 33 days at a time. Finally the vehicle design must be capable of automated cargo landings on the Moon in support of crewed missions.

It is not currently clear whether the two completing proposals for the original HLS contract – led respectively by Blue Origin and Dynetics – will participate in submitting proposals. Two of Blue Origin’s partners for the original HLS contract, Lockheed Martin and Northrop Grumman, have remained non-committal towards further participation in any additional lander projects since the SLD project was formally announced in March 2022.

Dynetics, however, were one of five companies to receive US $40.8 million each from NASA as a part of a 15-month initial SLD study initated in September 2021. As  a part of this work, Dynetics committed to risk-reduction activities and provide feedback on NASA’s requirements to cultivate industry capabilities for crewed lunar landing missions. Of the three original HLS  proposals, the Dynetics design – whilst the most expensive – most closely matched the requirements outlined in the SLD call and offered the advantage of being launched to the Moon using vehicles other than SLS. As such, there is some speculation they will respond to this new call for proposals.

An artist’s concept of the Dynetic’s HLS lander, originally rejected by NASA. Credit: Dynetics

SpaceX is excluded from responding to this new call for proposal. However, NASA indicating it plans to exercise an option in SpaceX’s existing contract and call on SpaceX to evolve is lunar Starship design “to meet an extended set of requirements for sustaining missions at the moon and conduct another crewed demonstration landing.”

Continue reading “Space Sunday: the Sun, Moon and updates”

Space Sunday: equations and launch scrubs

Dr. Frank Drake and his equation

Anyone with a reasonable interest in astronomy will recognise the above image as containing the Drake Equation, sometimes referred to as “the second most famous equation after E=Mc2

It was first proposed in 1961 by American astronomer and astronomer and astrophysicist Dr. Frank Drake as a probabilistic argument to estimate the number of active, communicative extraterrestrial civilisations in the Milky Way Galaxy. Its values are defined as:

N = the number of civilisations in our galaxy with which communication might be possible (i.e. which are on our current past light cone);

And:

R = the average rate of star formation in our Galaxy.

fp = the fraction of those stars that have planets.

ne = the average number of planets that can potentially support life per star that has planets.

fl = the fraction of planets that could support life that actually develop life at some point.

fi = the fraction of planets with life that actually go on to develop intelligent life (civilisations).

fc = the fraction of civilisations that develop a technology that releases detectable signs of their existence into space.

L = the length of time for which such civilizations release detectable signals into space.

In the decades since its initial publication, the Drake Equation has been widely critiqued by astronomers and mathematicians because the estimated values for several of its factors are highly conjectural  such being that the uncertainty associated with any of them so large, the equation cannot be used to draw firm conclusions.

However, these critiques actually miss the point behind Drake formulating the equation in the first place, because he was not attempting to quantify the number of extra-solar civilisations which might exist, but rather as a way to stimulate scientific dialogue about what had been very much looked upon as an outlier of research, and to help formulate constructive discussion on what is regarded on the first formalised discussion on the search for extra-terrestrial intelligence (SETI), as he noted in his memoirs:

As I planned the meeting, I realised a few day[s] ahead of time we needed an agenda. And so I wrote down all the things you needed to know to predict how hard it’s going to be to detect extra-terrestrial life. And looking at them it became pretty evident that if you multiplied all these together, you got a number, N, which is the number of detectable civilizations in our galaxy. This was aimed at the radio search, and not to search for primordial or primitive life forms.

– Frank Drake

Frank Drake not only hosted the first US meeting to discuss the potential for seeking signs of possible extra-terrestrial civilisations, he pioneered several of the earliest attempts to seek any such signals as demonstrating methods that might be used as a means to intentionally communicate our existence to other civilisations within the galaxy. As such, his work did much to put our speculative thinking about intelligences elsewhere in the galaxy on a solid foundation of scientific research, as will as being responsible for some for the foremost research in the field of modern radio astronomy.

This is his story.

Born in Chicago on May 28th, 1930, Frank Drake was drawn to the sciences and to electronics from an early age, and in order to further his education in both, he enlisted in the US Navy Reserve Officer Training Corps (ROTC).  This allowed him to obtain a scholarship at the prestigious Cornell University, ostensibly to obtain qualifications in electronics, but also study astronomy.

While at Cornell, Drake’s astronomy class were able to attend a lecture by astrophysicist Otto Struve. While his name may not be instantly recognised, Struve was one of the most distinguished astronomers of the mid-20th century, a member of a generational family of astronomers stretching by to the 18th century and Friedrich Georg Wilhelm von Struve. He was also one of the first astronomers to openly promote radio astronomy as a key to determining whether there might be other intelligences living in our galaxy – an idea his contemporaries tolerated, rather than embraced.

Struve’s presentation positively affected Drake, and following his required 1-year military service following graduation in 1951 (served as the Electronics Officer aboard the cruiser USS Albany), Drake enrolled at Harvard University, where gained his doctorate in astronomy, with a focus on radio astronomy.

Frank Drake in one of his official portraits at Green Bank observatory (1962). Credit: Green Bank

In 1956 Otto Struve was appointed as the first director of the National Radio Astronomy Observatory (NRAO)), and he started overseeing the establishment of a number of national radio astronomy centres across the United States. One of these was at Green Bank, Virginia, a facility Drake joined as a researcher in 1958. His initial work here started with the static arrays at Green Bank, carrying out the first ever mapping of the centre of the Milky Way galaxy, and the discovering that Jupiter has both an ionosphere and magnetosphere.

However, Struve was keen to enhance the facilities with steerable radio dishes, and to this end purchased an “off-the-shelf” 26 m dish and had engineer Edward Tatel (for whom it was later named) design a motorised mount for it so it could be pointed around the sky. This work was completed in 1959, and Struve turned to Drake to formulate the telescope’s first science mission.

At the time, Drake had just read an intriguing article in Nature magazine entitled Searching for Interstellar Communications. Within it, physicists Giuseppe Cocconi and Philip Morrison proposed using a large radio dish to monitor “incoming” radiation from stars along the 21-cm / 1,420.4 MHz wavelength – the radio frequency used by neutral hydrogen.  Given this is the most common element in the universe, Cocconi and Morrison speculated it would be logical landmark in the radio spectrum to manipulate as a message carrier.

Taking this idea, Drake developed Project Ozma, a three-month programme run at the start of 1960 to listen for any signals coming from the vicinity of either Tau Ceti or Epsilon Eridani. At the time, no-one knew if either star fielded planets (although both were found have at least one planet orbiting them almost 50 years after Drake’s experiment).

Frank Drake in front of the 85-1 (Tatel) Telescope. the first steerable telescope built at NRO Green Bank (and now one of 3 such telescopes, collectively referred to as the Green Bank Interferometer), used in Drake’s first SETI experiment, Project Ozma. Credit: NRAO Green Bank

Following Ozma, Drake was encouraged to formalise SETI research into a more co-ordinated effort (various programmes, such as Ohio State University’s work using the Big Ear telescope, were already in existence but without any real coordination). To this end, he helped put together the first small-scale meeting / conference on the subject in 1961 – the event at which he used his equation to  stimulate the discussion.

Among those attending were Otto Struve (now retired), Phillip Morrison, astronomers Carl Sagan and Su-Shu Huang, chemist Melvin Calvin, neuroscientist John C. Lilly, and inventor Barney Oliver. Together they called themselves The Order of the Dolphin (due to  Lilly’s work on dolphin communications), and together they laid the groundwork for a systematic approach to SETI research, which over the coming years would in turn give birth to numerous programmes, and more fully legitimise such research within scientific circles.

In the mid-1960s, and still based at Green Bank, Drake was nominated to spearhead converting the massive Arecibo Ionosphere Observatory  – originally built as a project to study the Earth’s ionosphere as a means of detecting nuclear warheads inbound towards the United States – into what would become more famously known as the Arecibo Observatory, for several decades the largest radio telescope in the world.

This work finished in 1969 when the National Science Foundation formally took over the Arecibo faculties, and two years later Drake was approached by Carl Sagan with another intriguing proposal. Sagan had himself been approached English journalist Eric Burgess – who at the time was writing about the upcoming NASA Pioneer 10 and Pioneer 11  missions – about the idea of sending a physical message out to the stars.

Continue reading “Space Sunday: equations and launch scrubs”

Space Sunday: galaxies, launches and health in space

Gz-13, as seen by the James Web Space Telescope, one of the earliest known galaxies in the universe and seen as it would have appeared just a few million years after the Bi Bang. Credit: NASA / ESA / CSA / STScI

The above image may not look to be much, but it in fact a glimpse at one of the most distance galaxies from our own, a place called Gz-13. It is so far away, the light captured by the image departed it about 300 million years after the universe itself was born.

Gz-13 is a part of a cluster of galaxies seen within one of the first set of images released by NASA from the James Webb Space Telescope (JWST), and which I covered in my previous Space Sunday update. So far away are these objects, that they can only be seen via the effect of gravitational lensing – using the gravity of an object much, much closer to our own solar system to “bend” the light from them and focus it so that JWST can capture images.

Gz-13 lies tucked away in the SMAC-0723 grouping of very distant objects. Originally imaged by the Hubble Space Telescope (HST), the grouping has been given sharp, new high-definition exposure by JWST. Some much definition, in fact, that GZ-13 hadn’t been seen by Hubble.

While it may seem like a blob of red-shifted light, massively distant objects like Gz-13 (and Gz-11, another far-distant galaxy that was seen when Hubble viewed SMACS-0723) are important targets for study, as they represent a period of time literally just a blink (in cosmic terms) after the universe went off with its Big Bang; thus thus represent an opportunity for us to understand what was going on very close to the origin of literally everything there has ever been.

SMACS 0723 as it appeared 4.6 billion years ago. Tucked away inside this cluster sits Gz-13. Credit: NASA/Goddard Space Centre / STScI

What is particularly interesting about the likes of Gz-11 and Gz-13 is that despite being formed just 150-200 million years after the first stars are believed to have started forming, they still have masses that suggest they are home to several billions stars with a mass equivalent to our own Sun. Thanks to them being so bright in the infra-red, they offer an unparalleled opportunity for astronomers to carry out extensive spectrographic analysis  to help us to discover more about them and the nature of the stars they contain – including, potentially, whether any of their stars might be surrounded by disks of dust and gas that might have gone on to form planets.

Given the nature of the expanding universe, Gz-11 and Gz-13 are liable to be just the tip of a massive iceberg of galaxies far, far, away that are waiting for JWST to find. This is turn will massively increase our total understanding of the nature of the universe, and the formation and growth of the galaxies within it. In fact, it is very possible that JWST will look so far out that we are looking almost back to the very edge of the Big Bang itself.

China Launches First Space Station Science Module

China has launched the first of two science modules to its nascent Tiangong Station (TSS).

The Wentian module was lifted into the sky atop a Long March 5B heavy-lift rocket at 06:25 UTC on Sunday, July 24th, the launch taking place from the Wenchang spaceport on the southern island of Hainan.

Measuring 17.9 metres in length and with a diameter of 4.2 metres, the module has an operational mass of around 23 tonnes, putting it on a par with US and international modules on the ISS. At the time of writing, the module was due to make an automated docking manoeuvres with Tianhe-1, the core module of the Chinese space station.

Chinese Space Station supplemental module Wentian. Credit: Leebrandoncremer via Wikipedia

Wentian, which literally means “quest for the heavens,” is the first of two science modules intended to join with Tinahe-1 to complete the currently-planned elements of TSS and bring its all-up mass to around 66 tonnes (the ISS, by comparison, masses 460 tonnes). In addition, operations aboard the station can be added-to through the use of Tianzhou automated re-supply vehicles.

The module’s docking will be overseen by the three crew of the Shenzhou 14 mission. It will initially dock with Tianhe’s forward docking port, where it will remain during initial tests and check-out by the crew to confirm its overall condition. The crew will then commence initial science activities, which will include a live broadcast via Chinese state media.

At some point in the future, Wentian will be relocated to a side port on Tianhe’s forward docking hub to form one arm of an eventual “T” that will be made by the core module and the two science modules, leaving the forward port free for visiting crews, and the after port at the far end of Tianhe available for visiting Tianzhou vehicles.

Whilst classified a science module, Wentian is actually a multi-purpose facility. It includes an airlock of its own to enable crew members to complete space walks, it has an external robot arm of its own to assist with such spacewalks, and additional living space for 3 tiakonauts, allowing up to six to live in comfort on the station during hand-over periods. The first such hand-over (similar in nature to ISS handovers) is due to take place in December 2022, when the crew of Shenzhou 14 pass the station over to the 3-person Shenzhou 15 crew. However, prior to that event, the second science module, called Mengtian (“Dreaming of Heavens”), is due to be launched to the station in October.

NASA Sets Artemis-1 Launch Dates

On July 20th, 2022, NASA announced they are targeting three dates at the end of August / beginning of September for the first flight of their Space Launch System (SLS) super rocket which sits at the heart of their plans for a return to the Moon.

The Artmis-1 mission will launch an uncrewed Orion Multi-Purpose Crew Vehicle (MPCV) on an extended mission to cislunar space. Each of the three launch dates has different launch windows and mission durations:

  • August 29th: the launch window runs from 12:33 to 14:33 UTC, and would result in a 42-day mission ending with a splashdown on October 10th.
  • September 2nd: the launch window runs from 16:48 to 18:48 UTC, and would result in a 39-day mission splashing down on October 11th.
  • September 5th: the launch window opens at 21:12 UTC for 90 minutes, and would result in a 42-day mission splashing down on October 17th.
The Artemis-1 Space Launch System rocket, seen during the initial Wet Dress Rehearsal test in April 2022. Credit: NASA

Splashdown for all three launch opportunities will occur off the coast of San Diego, California.

The dates themselves have been defined based on the need to complete post-Wet Dress Rehearsal  test work on the vehicle. They all represent “long-class” flights for the Orion, with Artmis-1 originally being planned around shorter 4-week flights in order to test out all of its handling characteristics in cislunar space. However, given all of the delays thus far experienced with Artemis-1, NASA opted to push for these launch dates rather wait until the end of October when windows for shorter-during flights would open, together with a further rick of slippage of the launch back into 2023.

Continue reading “Space Sunday: galaxies, launches and health in space”

Space Sunday: Webb’s views, booster bang + Rogozin’s roulette

Where they are: the five subjects of the first five science images release by NASA for the James Webb Space Telescope (JWST). 1: the Carina Nebula; 2. the Southern Ring Nebula; 3. Stephan’s Quintet; 4. WASP-96b; 5. SMACS 0723. Credit: NASA/Goddard Space Centre / STScI
The first series of science images from the James Webb Space Telescope (JWST) were released on July 12th, 2022 rightly grabbing the headlines around the world, revealing as they did elements of our universe and our own galaxy in stunning detail and offering a superb launch for the observatory’s science mission.

At the time of their release, NASA also confirmed that, thanks to the extreme accuracy achieved by the European Ariane 5 rocket in delivering the observatory into is transfer orbit which allowed JWST to establish itself in its L2 position halo orbit, 1.6 million km from Earth, sufficient propellants remained aboard the observatory for it to operate for around 20 years – double its original extended mission time.

The mission itself is broken into periods of 12 months apiece, with science institutions, universities, etc., from around the world able to submit papers outlying studies they like to carry out using JWST to the Space Telescope Science Institute (STScI) in Baltimore, USA which form the management and operational centre for both JWST and the Hubble Space Telescope (HST). As such, the initial images selected for release on July 12th represent study targets for JWST accepted for its first year of observational science – but they are not the only targets. Since formally commencing its science programme in June, JWST has already gathered around 40 terabytes of images and data, and following the high-profile release of the initial images, on July 14th, 2022, STScI started issuing raw images of other targets so far examined by the observatory, including images of objects without our own solar system.

Webb is designed to collect light across the entire red to mid-infrared spectrum wavelengths of light that are blocked by Earth’s atmosphere, and while Hubble crosses from visible light into the near-infrared, JWST has a light collection area 5 times greater than that of HST. Taken together, these facts mean that JWST can reveal objects near and far with a lot more detail than we’ve ever been able to see them, and can also see much further out in the cosmos, allowing us to see the light of objects as they appeared close to the birth of the universe. Add this to the fact that the four science instruments on JWST can be combined to operate in a total of 17 different modes, and JWST is genuinely unparalleled in its capabilities.

The following is a brief summary of the images released on July 12th.

Carina Nebula

Lying some 7,600 light-years away and visible in southern hemisphere skies within the constellation Carina, this nebula (NGC 3372) is a familiar sight among astronomical photographs and studies. It is a massive birth-place of stars, with multiple young stellar groupings like Trumpler 14, and Trumpler 16.

The former, measuring just 6 light-years across (or roughly 1.5 times the distance between our Sun and the Alpha Centauri system) is just half a million years old – but it is home to around 2,000 young stars! Slightly older, Trumpler 16 is home to two of the most luminous stars in our galaxy: Eta Carinae and WR 25. These are two of the most luminous objects in our galaxy – while both are invisible to the naked eye on Earth, they are nevertheless several million times brighter than the Sun.

The “cosmic Cliffs” of NGC within the Carina Nebula, showing the blue “bowl” of hot stars that have pushed interstellar dust and gases into to a ring that resembles towering cliffs and mountains, and within which younger, new stars can be seen. Credit: NASA/Goddard Space Centre / STScI

Neither of these stellar groups was the focus in the Carina Nebula image release on July 12th. This honour went to the “Cosmic Cliffs”, part of a nebula-within-a-nebula (NGC 3324). A ring of dust and debris, it has been formed by the young, super-hot, super-active blue-white stars at the centre of NGC3324 (seen at the top of the image above) generating a collective powerful radiative force that has pushed the remaining gases and dust left over from their formation outwards to a point where the pressure of their own radiation is matched by that of the surrounding larger nebula.

Normally invisible to the naked eye, the portion of the “Cosmic Cliffs” have been beautifully rendered using images from both the Near-Infrared Camera (NIRCam) and the Mid-InfraRed Instrument (MIRI) on JWST, which have been processed to produce a remarkable composite image that reveals never-before-seen details. Within this ring of material, compression and gravity are combining to create even younger stars, many revealed in this image for the first time – with some even showing protostellar jets of material shooting outwards from them. Images like this shed enormous light (so to speak!) on the process of star formation.

Southern Ring Nebula

Catalogued as NGC 3132, the Southern Ring Nebula stands in contrast to the Carina Nebula, being the home of a binary star system where one of the stars is in its death-throes.

The pairing sits in a tight mutual orbit, and the elder of the two stars has gone through a series of events where it has thrown off shells of gas and mass, which are being mutually “stirred” by the two stars as they continue to orbit one another, leading to a complex pattern of gases around both.

The Southern Ring Nebula as seen by JWST’s NIRCam (l) and MIRI (r). Credit: NASA/Goddard Space Centre / STScI

JWST imaged the nebula with both NIRCam (seen on the left, above) and MIRI (seen on the right), with the latter showing for the first time that the second star is surrounded by dust, suggesting a more “recent” ejection of mass. The brighter star (visible in both images) is in an earlier stage of its stellar evolution and will probably eject its own planetary nebula in the future.

Studies of phenomena like the Southern Cross Nebula is like watching a slow motion film of a star’s evolution towards the end of its life, each of the shells of gas and dust from outer to inner representing increasingly more recent events in its life, allowing astronomers gain insight in the life and death of stars, whilst studies of the gases released provide insight into how these delicate layers of gas and dust will dissipate into surrounding space.

Stephan’s Quintet

This is a visual grouping of five galaxies, four of which (called the Hickson Compact Group 92) are a genuine grouping of galaxies that are gradually being drawn together by gravity, and will all eventually merge. The fifth member of the quintet is the result of line-of-sight alignment, rather than an actual part of the group. It is possibly best known for its appearance in the classic film It’s a Wonderful Life.

Imaged numerous times in the past, JWST nevertheless reveals the quintet in a new light via a mosaic image that represents Webb’s largest image to date, containing over 150 million pixels and comprising 1,000 individual pictures of the galactic group.

Stephan’s Quintet, comprising a close-knit group of four galaxies, two of which have already merged (centre right) to form NGC 7318. Also visible in the image are clouds of sat-forming dust and material, and the shockwave of the NGC 7318 merging rippling through NGC 7319. Credit: NASA/Goddard Space Centre / STScI

The quartet of galaxies are some 280 million light-years from our own, and of particular note in this composite image is the details of gaseous clouds where star formation is going on; the clear view of the two galaxies in the group which have already collided (UGC 12099 and UGC 12100, now collectively classified as NGC 7318) – the lower right of the “three” close-packed galaxies in the central group – and the white shockwaves of that collision as they sweep towards the top right galaxy, NGC 7319.

Continue reading “Space Sunday: Webb’s views, booster bang + Rogozin’s roulette”

Space Sunday: JWST, interstellar communications and Mars sailplanes

The “Pillars of Destruction” (aka Region R44) within the Carina Nebula, 7,600 light-years from Earth, as seen by the MUSE instrument on ESO’s Very Large Telescope. Towering fields of dust, the pillars are slowly being destroyed by the the stars they helped form; while the nebula is one of the focal-points for initial science imaging by the James Webb Space Telescope. Credit: ESO

Our first glimpse through the eyes of the James Webb Space Telescope (JWST) will be unveiled through a live broadcast on Tuesday, July 12th at 14:30 UTC. However, on Friday, July 8th, NASA announced details on what will be featured in the broadcast and the images that will be published during the presentation, promising that the latter will reveal an unprecedented look into some of the deepest views yet of the cosmos.

The targets were selected by an international committee of scientists from NASA, the European Space Agency (ESA), the Canadian Space Agency (CSA) and the Space Telescope Science Institute in Maryland, which manages the observatory. They include:

  • The Carina Nebula (NGC 3372): lying some 7,600 light-years away, and visible in southern hemisphere skies, where it appears to lie within the constellation Carina, this nebula is the home of the famous “Pillars of Destruction”, long finger-like structures of cosmic gas and dust.
  • Southern Ring Nebula (NGC 3132): appearing to lay within the constellation of Vela (also visible in the southern hemisphere sky) this distinctive nebula of gas and material surrounds dying star is some 2,000 light-years from Earth.
  • Stephan’s Quintet: a visual grouping of five galaxies, four of which (called the Hickson Compact Group92) are a genuine grouping of galaxies that are gradually being drawn together by gravity, and will all eventually merge. The fifth member of the quintet is the result of line-of-sight alignment, rather than an actual part of the group.
  • WASP-96 b: a “hot Saturn” exoplanet orbiting the star WASP-96, some 1,120 light-years away, within the southern constellation of Phoenix. With a mass roughly half that of Jupiter, the planet orbits its parent every 3.4 terrestrial days and is the first known planet with an entirely cloudless atmosphere, which has a profoundly strong sodium signature.
  • SMACS J0723.3-7327: an experiment in using gravitational lensing, using the gravity of relatively “nearby” galaxies to “bend” the light from much more distance galaxies to obtain a deep-field view of their stars.
The initial science images from JWST will be part of a science briefing scheduled for 4:30 UTC. on July 12th. Credit: NASA

The presentation and images will mark the first time “operational” data and images relating to scientific targets for the observatory have been made public since the completion of all tests relating to the calibration and commissioning of its four science instruments, all of which allow JWST to operate in a total of 17 different science modes.

It is believed that even though only initial studies of their targets, the images captured by the telescope have stunned science teams and already led to increased understanding of exoplanets, galaxies and the universe itself.

Could Stars be used as Communications Relays?

In June I covered a proposal suggesting the Sun’s gravity could be used to help image exoplanets orbiting other stars using gravitational lensing (see:  Space Sunday: exoplanets, starship and the Sun as a lens). Now a paper accepted for publication in The Astronomical Journal lays out the idea that the lensing effect of the Sun’s gravity, and that of other stars, could be used as some kind of interstellar communications network.

The study discusses the idea that gravitational lensing, involving the bending of light as it passes by massive objects like stars and black holes, could be used to focus communications between one point and another, amplifying the signal like an interstellar cell phone tower.

For the purposes of the paper, a team of students at Penn State University working under Jason Wright, professor of astronomy and astrophysics and the director of the Penn State Extra-terrestrial Intelligence Centre, used the Sun as a model, calculating that the gravitational focus on the solar lensing effect lies some 550 AU out from the Sun – or a distance equitable to roughly half-way between the orbits of Jupiter and Saturn.

Communications across interstellar distances could take advantage of a star’s ability to focus and directing communication signals through an effect called gravitational lensing. A signal from—or passing through—a relay probe would bend due to gravity as it passes by the star. The warped space around the star acts somewhat like a lens or transmitter, focusing the beam towards an itended target. Credit: Dani Zemba / Penn State

This is the point where a communications satellite could be placed such that it could use the Einstein Ring effect of gravitational lensing by the Sun to focus its signals on a distant target – and also receive incoming communications from that target as the Sun’s gravity focuses them down onto the satellite.

The most obvious use of such a system would be to enable communications with deep-space probes we might eventually send to nearby stars (assuming they could be accelerated to reach said stars in a reasonably time-frame). However, the students also noted that if the Sun were to be a part of so alien communications network, then we now have a sphere around it where we might detect any relay, which we might try to eavesdrop on.

Whilst a pretty far-fetched idea in terms of an “alien relay station” sitting in our own back yard, the study does offer some food for thought in how signals from ET (if they exist) might leverage stellar objects, and thus offers a potential new avenue to be explored within SETI and CETI (as in Communications) research.

Exploring Mars by Air: the Case for the Sailplane

The success of the Mars Ingenuity helicopter has been encouraging engineers to consider and reconsider all options for remote aerial observations of the Red Planet over the course of the past year. Additional methods for birds-eye views of Mars would not only provide higher resolution data on the landscapes where rovers can’t go — such as canyons and volcanoes — but also could include studying atmospheric and climate processes that current orbiters and rovers aren’t outfitted to observe.

Once such option that had been considered years ago and is now coming back into focus is that of a sailplane. In particular, students at the University of Arizona have been investigating the possible use of small, relatively lightweight (just 5 kg) unpowered sailplanes that could be carried to Mars as secondary payloads alongside larger missions.

Aerospace engineering doctoral student Adrien Bouskela (left) and aerospace and mechanical engineering professor Sergey Shkarayev hold an experimental Mars sailplane. They hope to one day send a custom version of a similar plane to Mars. Credit: Emily Dieckman/College of Engineering.

Protected through their entry into the Martian atmosphere, these sailplanes would fall free from their aeroshells to unfold their 3-metre wingspan to use the so-call boundary layer of atmosphere known to exist around Mars and which is of considerable interest to scientists.

You have this really important, critical piece in this planetary boundary layer, like in the first few kilometres above the ground. This is where all the exchanges between the surface and atmosphere happen. This is where the dust is picked up and sent into the atmosphere, where trace gases are mixed, where the modulation of large-scale winds by mountain-valley flows happen. And we just don’t have very much data about it.

– Alexandre Kling, NASA’s Mars Climate Modelling Centre

Potentially also using fully or partially inflatable fuselage, such sailplanes could ride the wind and air pressure, gathering data whilst exploiting atmospheric wind gradients for dynamic soaring to extend their gradual descent to the ground.

Despite their relatively light weight, the students believe the sailplanes would be capable of carrying an array of navigation sensors, a camera system to images the terrain below it, and temperature and gas sensors to gather information about the Martian atmosphere. As a part of their studies, the students have experimented with radio-controlled sailplanes adjusted to fly themselves and which have been lifted to altitude under weather balloons before being released to see how they manage the dynamics of a descent through Earth’s atmosphere.

he Mars sailplanes will contain a custom-designed array of navigation sensors, as well as a camera and temperature and gas sensors to gather information about the Martian atmosphere and landscape. Credit: Emily Dieckman/College of Engineering

In addition, the students have used computer modelling to research general vehicle handling within the far more tenuous Martian atmosphere. A particular technique used in sailplaning is to use updrafts and thermals in which a pilot can circle and gain lift to increase altitude. Mars is known to have similar phenomena, and the modelling shows that they could be used in a manner akin to sailplaning on Earth – with the added advantage that the higher effective wind speeds often recorded with such updrafts on Mars have the potential to help carry the sailplanes over much greater distances.

If such vehicles were released over terrain features such as Gale Crater (home of the Mars Science Laboratory rover Curiosity or Jezero Crater, home to the Perseverance Mars 2020 rover, they could be used for detailed high-altitude surveys of the craters, using updrafts as the crater walls to regain momentum whilst mapping the crater floors for surface exploration. However, they could also be used in the first highly-details studies of the nature of Vallis Marineris, the 5,000-km long “Grand Canyon” of Mars.

According to the modelling completed by the students, a sailplane could use the rugged, deep base of the canyon, rich in mesas and plateaus to regularly recover 6-11%  lift energy on a cyclic basis, which together with the higher atmospheric pressure within the canyon system could allow each sailplane to fly for “days”, offering unparalleled opportunities to study this unique environment.

A further attraction with sailplanes is that of cost: development of a suitable glider vehicle could be measured in years rather than decades, utilising common off-the-shelf parts, particularly where instruments are concerned, with most of the effort going into the delivery / deployment system, gaining a better understanding of the Martian atmosphere and its thermal qualities in order to better determine vehicle flight characteristics, and in how to develop the means to recharge the sailplane’s batteries to power its instruments and controls without relying on a potentially cumbersome solar array system.

Currently, the work by the students has been a project largely internal to the university; however, Kling has worked with the team, and he and professor Sergey Shkarayev from the university who has overseen the work, hope that a formal proposal to extend the research might yield NASA funding.