A Starship / Super Heavy pairing lifts-off from a dedicated launch facility in this still from an animated video produced by SpaceX for the September 28th, 2019 update. Credit: SpaceX
On the occasion of the eleventh anniversary of SpaceX achieving orbit for the first time with their Falcon 1 rocket on September 28th, 2008, CEO Elon Musk presented an update on the company’s progress developing its massive Super Heavy booster and interplanetary class vehicle, Starship.
It has been some 12 months since the last update on the development of the two vehicles – the last update really being overshadowed by the announcement SpaceX planned to fly a Japanese billionaire and his entourage around the Moon and back (see Moon trips, Mr Spock’s “home” and roving an asteroid for more), and the programme has moved on significantly since then, as indicated by the fact that the 2019 update took place at the SpaceX facilities in Boca Chica and against the backdrop of the first of the Starship prototype vehicle.
Starship Mk1 under construction at the SpaceX facilities near Boca Chica, Texas. Credit: unknown
Since its first public unveiling in 2016, the Starship / Super Heavy combination has been through a number of iterations and name changes. However, it is fair to say that things have now settled down on the design front, and what was presented at Boca Chica is liable to remain largely unchanged, assuming everything proceeds as SpaceX hopes.
In this, the flight capable prototype Starship at Boca Chica is the first in a series of such vehicles. A second is under construction at the SpaceX facilities in Cocoa, Florida, and three more are planned, one of which will be used to make the first orbital flight within the next 6 months, and Musk suggesting another could be used in a crewed orbital flight within the next 12 months – which sounds exceptionally ambitious. Construction of the two initial Starship prototypes has not exactly been secret: both have been literally assembled in the open. So even ahead of the September 28th event, some were already developing renderings of the new Starship design compared to the last known iteration.
A rendering by Kimi Talvitie comparing the 2018 design for Starship (l) with the prototype (r). The rendering of the 2019 prototype was based on direct feedback from Elon Musk
The new design sees some significant changes in Starship – notably with the fins, canards and landing legs. The 2018 variant was marked by three large fins, two of which would be actuated (hinged for up / down motion relative to the hull) for atmospheric flight, with all three fins containing the vehicle’s landing legs. At the time of that design, I commented that this approach appeared risky: a heavy landing on the Moon or Mars might conceivably damage one of the actuated fins, affecting the vehicle’s ability to undertake atmospheric flight on its return to Earth.
With the new design, the fins are reduced to two and reshaped, both of which are actuated to hinge “up” and “down”. In addition, the landing system is now independent of the fins, removing the greater part of the risk of damaging them on landing. The number of landing legs is also increased to six. At the forward end of the vehicle, the canards are enlarged and hinged in a similar manner to the fins.
Starship’s basic specification. Note the “dry” mass of 85 tonnes is incorrectly stated in the slide: it is expected the production version of Starship will mass around 120 tonnes (the prototype masses around 200 tonnes. Credit: SpaceX
The remaining aspects of the design are more-or-less unchanged as far as the body of the ship is concerned: it will be some 50 metres (162.5ft) in length and have a diameter of 9m (29ft). The forward end of the vehicle will be given over to crew and passengers or cargo (or a mix of the two), although Musk now estimates the vehicle will – with the aid of the Super Heavy booster – be lifting up to 150 tonnes to low Earth orbit – an increase of roughly a third – and return up to 50 tonnes to Earth.
To help achieve this, the motor system has been slight revised. While six engines will still be used, three will now be optimised for vacuum thrust, ideal for orbital flight and pushing the vehicle out to the Moon or Mars, and the remaining three optimised for sea level thrust and capable of being gimballed for use during a descent through an atmosphere and landing.
Starship’s motor arrangement: three central Raptor engines optimised for sea level thrust and capable of gimballing and three outer vacuum optimised motors with fixed, large diameter exhaust bells for maximum efficiency. The “boxes” visible in the rendering are potentially additional cargo bins. Credit: SpaceX
During the presentation, Musk explained the rationale behind the use of 301 cold rolled stainless steel in the design, noting a number of reasons. Firstly, the cold rolling process results in a stronger, light finished product, and this becomes even stronger when exposed to the very low temperatures of cryogenic fuels. Thus, Starship and Super Heavy in theory have a structural strength equitable to that of carbon composites – but at a much lower overall mass.
Secondly, the cold rolled steel has very high melt temperatures, reducing the amount of direct heat shielding required, again reducing the vehicle’s overall mass. It is also both highly corrosion-resistant and easy to work with. This means that basic repairs to a vehicle on the surface of the Moon or Mars could be effected, or even that a Starship could even be dismantled and the steel from the hull re-purposed. Finally, there’s the fact that all these advantages are gained in a product costing around 2% that of an equivalent mass of carbon composite.
Starship Mk 1 filmed during the September 28th livestream event. Credit: SpaceX
In terms of heat shielding, the “windward” side of Starship (the side facing the fictional heat of entry into an atmosphere) will be coated with lightweight ceramic tiles. Somewhat similar in nature to those used within the space shuttle, they will be of a hardier material and less prone to damage. The re-entry profile was also discussed, with Musk comparing Starship to a sky diver.
To explain: the vehicle will approach the atmosphere at a relatively high 60-degree incidence, using the heat generated by contact with the upper atmosphere to slow its velocity from Mach 25 to a point where, once within the denser atmosphere, the vehicle is literally falling more-or-less horizontally. The fins and canards can then be used to maintain the vehicles orientation in a similar manner to that of a sky diver using his arms and legs. in addition, the lift generated by fins and canards will further help slow its descent until, roughly 2 km above the ground, the vehicle will rotate to a vertical position and use the three gimballed Raptor motors to make a propulsive, tail-first landing.
SpaceX plan to offer Starship in support of lunar operations – but the company’s goal is to establish a permanent human presence on Mars. Credit: SpaceX
Starship Mk 1 is equipped with the same sea level optimised Raptor motors as intended for the production vehicles. SpaceX hope to see it make at least one flight before the end of the year – although the company has yet to secure a permit from the US Federal Aviation Authority to commence flights. This first attempt will be to an altitude of around 20 km (12.5 mi) before a descent and landing. If successful, the test programme involving the various prototype vehicles will unfold from there.
The bulky Vikram lander, with the Pragyan rover”garaged” inside, is hoisted aloft in a clean room, ready to be mated to the “top” of the Chandrayaan-2 orbiter (right). One section of the payload fairing that enclosed the craft during launch is visible in the background. Credit: ISRO
On Friday, September 6th, India was due to become the fourth country to successfully reach the surface of the Moon, with the touch-down of the Vikram lander, part of the Chandrayaan-2 (“moon craft-2” in Hindi) mission.
Launched in late July 2019, Chandrayaan-2 was set to be the latest in a series of high-profile missions undertaken by the Indian Space Research Organisation (ISRO) over the course of the last 11 years, which have included the Chandrayaan-1 lunar orbiter (2008/2009) and the Mangalayaan (“Mars-craft”), launched in 2013 and still operational today.
As I’ve noted in recent Space Sunday articles, Chandrayaan-2 comprises three parts: the orbiter vehicle, the Vikram lander and a small rover called Pragyan (“Wisdom” in Hindi) carried by the lander. Vikram departed the orbiter vehicle on Monday, September 2nd, allowing it to begin a series of manoeuvres in readiness for a final decent and landing, scheduled for Friday, September 6th (western time, the early hours of Saturday, September 7th for India) in the Moon’s South polar region.
An artist’s impression of the Vikram lander coming in to land in the Moon’s south polar region. Credit: ISRO official video
Initially, that final descent started well enough, with the lander about 550 km (344 mi) from the south pole as it fired its descent motor start the start of its final approach. At an altitude of 6 km (3.75 mi), it started a final sequence of engine burns referred to as the “fine braking phase”. Then all communications ceased.
ISRO issued a statement that the vehicle was performing nominally until around 2.1 km above the Moon, when the loss of communications occurred. However, images of the data received from the vehicle and released by ISRO appeared to suggest telemetry was being received when the lander was within 400 m of the lunar surface – and altitude at which it would be fully under its automatic guidance and landing software, and not reliant on commands from Earth. This seemed to suggest Vikram may have made a landing.
ISO stated communications with the Vikram lander were lost some 2.1 km above ground. However, a graphic of the vehicle’s descent towards the Moon (green above), appears to suggest telemetry was lost when the vehicle was between 300-400m above the lunar surface, and that it had drifted perhaps a mile from its planned descent track (red). If accurate, this suggests Vikram was in the fully automated terminal descent phase of its landing. Credit: ISRO
This idea gained ground as this article was being prepared, when an article published by Asia News international suggested Vikram has been spotted on the surface of the Moon, possibly 500m to 1 kilometre from its designated landing point. The article quotes ISRO’s director, Kailasavadivoo Sivan as saying:
We’ve found the location of Vikram Lander on lunar surface & orbiter has clicked a thermal image of Lander. But there is no communication yet. We are trying to have contact. It will be communicated soon.
Since then, the report has been repeated numerous times through various media (including an entirely UNofficial and unverified “ISRO Official Update” Twitter account) without (at the time of publication) official confirmation. This has made it hard to determine the veracity of the ANI report. Hopefully, the situation will become clearer in the coming days. One thing that could help define the lander’s condition would be an image captured by Chandrayaan-2’s main imaging camera. With a resolution of a third of a metre, it is the highest resolution camera in operation around the Moon.
The planned landing site for the Vikram lander. Credit: ISRO
But even though the lander and rover may have been lost, the mission is far from over; the orbiter continues to function perfectly. It also carries the bulk of the mission’s science experiments – eight of the 13 carried by the mission. he data gathered by these systems should enable scientists to compile detailed maps of the lunar surface, revealing key insights about the Moon’s elemental composition, formation and evolution, and potentially help in assessing the moon’s stores of water ice.
In this latter regard, the mission builds on work performed by Chandrayaan-1, which revealed water is present at the lunar poles, with subsequent studies suggesting much of this water is ice on the floors of polar craters, which have been in permanent shadow for billions of years. If this ice is easily accessible, it could be a critical enabling resource for the eventual human settlement of the moon, providing water, oxygen and fuel (hydrogen).
In all, Chandrayaan-2 is expected to operate for some 7 years.
Proxima Centauri: An Angry Star with Bad News for its Planet
In 2016, I wrote about Proixma b, a planet roughly 1.5 times the mass of Earth orbiting our nearest stellar neighbour, Proxima Centauri, 4.25 light years away (see: Exoplanets, dark matter, rovers and recoveries). Since then, and as a result of the planet being within the star’s zone of habitability, there has been a lot of debate about the potential for it to support life.
An artist’s impression of Proxima b with Proxima Centauri low on the horizon. The double star above and to the right of it is Alpha Centauri A and B. Credit: ESO
Numerical models have indicated that Proxima b probably lost a large amount of its water in its early life stages, possibly as much as one of Earth’s oceans. however, those models also suggest liquid water could have survived in warmer regions of the planet – such as on the side of the planet facing its star (Proxima b is potentially tidally locked with its parent star, always keeping the same face towards it). This means other factors that might affect habitability must be examined. Chief among these is the overall activity of the parent star – notably flares, coronal mass ejections and strong UV flux -, all of which can erode a planet’s atmosphere, rendering it uninhabitable in the long term.
That Proxima Centauri is very active with flares has been known for some time, as has been the star’s ability to generate “super-flares”, one of which in 2016 briefly raised the star’s brightness to the point of making it briefly visible to the naked eye from Earth. This activity has suggested that Proxima b is unlikely to support life (see: Curiosity’s 5th, Proxima b and WASP-121b). But the debate has remained.
Over the past year, a team of scientists at the Konkoly Observatory in Hungary have been using data from the Transiting Exoplanet Survey Satellite (TESS) to observe Proxima Centauri’s flare activity over a two month period, split between April and June 2019. They found that in the roughly 55-day period, the star pent around 7% of its time violently flaring, with a total of 72 relatively large-scale flares observed. In particular, the energy of the eruptions put them as not far below “super flare” status, suggesting the star could produce a super flare perhaps once every two years.
TESS data on flare activity on Proxima Centauri: yellow triangles indicate flare activity, green triangles show particularly violent flare events. Credit: Krisztián Vida / Konkoly Observatory
Such frequent, high-energy eruptions almost certainly have a severe impact on the atmosphere of Proxima Centauri b, disrupting it to a point where it cannot reach any steady state, leaving it continuously in a state of disruption and alteration, making the potential for the planet to support life even more remote. However, it also raises a curiosity about the star: the underlying magnetic frequency evidenced by Proxima Centaur. Such activity is normally associated with fast-rotating stars with periods of a few days. However, Proxima Centauri has a rotation period of ~80 days; so why it should be so active is now a subject for investigation.
The “Flying Water Tank”, aka “R2D2’s Dad”, otherwise know as the Starhopper – rises to 120m (500ft) during its second major test flight, August 27th, 2019. Credit: SpaceX
SpaceX successfully flew their Starhopper vehicle – designed to prove the viability of their upcoming Starship space vehicle – on August 27th, in its most complex test flight to date.
The Starhopper craft, dubbed “the flying water tank” on account it both lacks its conical nose (damaged beyond repair during a storm at the start of the year) and the fact it was fabricated for SpaceX by a company that specialises in building water tanks, lifted off from a pad at SpaceX’s test site in Boca Chica, Texas, rising vertically to a height of 150 metres (488 ft) before translating to horizontal flight to crab across to another pad at the test facility and then descended under power to touch down once more.
While the flight lasted less than a minute, it has, according to Musk, paved the way for two dramatic follow-up flights. As well as the Starhopper vehicle, SpaceX is currently building two full-size Starship prototypes – “Mk 1” is being built at Boca Chica, with “MK 2” under construction in Florida. It appears that the “Mk 1” vehicle will be used for the 20km flight.
Starship Mk 2 on the left of the image, standing upright and with additional elements nearby, under construction in Cocoa, Florida. Credit: SpaceX
Musk’s announcement of a potential attempt to reach orbital altitude drew questions on whether SpaceX plan to use their Super Heavy – essentially the “first stage” for Starship launches – with one of the Starship prototypes, or just make the attempt with the Starship on its own. In the past, Musk has indicated that a fuelled but unladen Starship should have the power to achieve orbit, but that would presumably be using all six of an operational Starship’s Raptor engines. By comparison, the Starhopper has a single Raptor motor and the Starship Mk 1 and Mk 2 craft will have 3 Raptors – at least initially.
As it stands, the “first generation” of Starship / Super Heavy is designed to be 9m (29 ft) in diameter and stand around 118m (390 ft) tall on the launch pad. Super Heavy is to be powered by 31 Raptor engines and the 48m tall Starship by 6 Raptors. Together, SpaceX stated that they will be capable of lifting around 100 tonnes of payload to orbit, with Starship capable of reaching the Moon or Mars with that payload or up to 100 crew and passengers.
All of that is pretty mind-boggling. If possible, it will make Starship / Super Heavy the most powerful launch system ever built in terms of thrust. But SpaceX is apparently going to go beyond that. Following the Starhopper test, and responding to a question, Musk indicated that a “next generation” craft based on Starship / Super Heavy could follow in “several years”. While planning a follow-up to Starship / Super Heavy is not surprising, the scale of the follow-up version is: in a further tweet, Musk suggested it will be 18m (60 ft) in diameter – twice that of Starship / Super Heavy.
Mathematics tells us that doubling the diameter of a circle quadruples its area. This means that if the current ratio of dimensions for Starship / Super Heavy is retained, the “next generation” version would stand 230 m (780 ft) tall and have eight times both the surface area and propellant tank volume of the current Starship / Super Heavy. All of which leads to a fuelled launch mass of around 40,000 tonnes. All of which is, frankly, entering the realm of idiocy; as I’ve previously (and subjectively) opined, it’s hard to see a launch vehicle with a 100-tonne payload mass being commercially viable unless the launch costs are such that it can turn a profit lifting around 5-10 tonne to orbit for the majority of its flights. As such, a vehicle twice the size (even if possible) has little to no chance, outside of highly specialised (and limited) launch roles.
An artist’s impression of a future “next generation” Starship / Super Heavy launch combination compared to SpaceX’s current family of launch vehicles, the current (2018) and previous (2016 and 2017) BFR designs. This assumes the “next generation” vehicle will have Musk’s stated 18m diameter and retain the same proportions as the current Starship / Super Heavy combination. Credit: Teslerati.
At such a size and mass, the new vehicle would require 100 Raptor motors just to get off the pad – or a system of engines several times more powerful. Take the noise and vibration issues this would introduce to the system, and I’ll say that it just isn’t going to happen. In the meantime, Musk is promising a public update on the status of Starship / Super Heavy on September 28th, 2019.
An artist’s impression of Europa Clipper (previously the Europa Multiple Flyby Mission), due for launch in 2022 or 2023 (depending on the launch vehicle used) making a flyby of Europa. Credit: NASA
There are a number of places within our solar system where life may have come to pass – and indeed, may still exist – beyond the Earth. There’s Mars, Saturn’s massive moon Titan, and the so-called “icy world” moons, such as Neptune’s Triton, Saturn’s Enceladus, and Jupiter’s Europa, all of which may harbour sub-surface oceans between their icy crusts and solid interiors.
Of these moons, Enceladus has shown clear signs of activity relating to the existence of a sub-surface ocean: the ESA / NASA Cassini mission captured images of great plumes of water erupting from the moon’s south polar region, and the Cassini vehicle passed through this plumes towards the end of its mission to “taste” them, confirm they were predominantly water.
However, the icy world that has garnered the most interest in terms of detailed study remains Jupiter’s Europa. Currently, there are two missions being developed to probe Europa in greater detail than ever before: NASA’s Europa Clipper and ESA’s Jupiter Icy Moons Explorer (JUICE).
Europe’s subsurface ocean as it might exist – a place that might support life. Credit: NASA
Europa Clipper has had something of an up-and-down ride. Originally, scientists wanted to send a vehicle to study all of the icy moons around Jupiter – Europa, Callisto and mighty Ganymede. However, the US $16 billion price tag for the mission (including vehicle development, launch and operation) was too high. It was scaled back to a more modest US $4.3 billion mission, the Europa Orbiter, which would have included a lander. Then it was scaled back again to a US $2 billion mission.
In 2014, the mission eventually morphed into the Europa Multiple Flyby mission: rather than placing a vehicle directly in orbit around Europa, this would put the vehicle in orbit around Jupiter from where it would be able to make multiple fly-bys of Europa. This then became Europa Clipper – which has still suffered from attempts to axe it, surviving only because it has very strong support within the US Congress.
This support has allowed the mission to both receive continued funding and proceed through various design and review activities. As a part of this, on Monday, August 19th, 2019, NASA announced that it had formally confirmed the mission can proceed to what is called Phase C, a process that will see the mission through the final spacecraft design and then on to assembly and testing.
We are all excited about the decision that moves the Europa Clipper mission one key step closer to unlocking the mysteries of this ocean world.
– Thomas Zurbuchen, NASA associate administrator for science
While Enceladus was the first moon where we positively witnessed plumes of water ice erupting from the surface (2005), evidence that similar outgassing may be occurring at Europa has been gathered by the Hubble Space Telescope. This information, gathered in the form of images, and data gathered by the magnetometer instrument carried by NASA’s Galileo space vehicle that surveyed Jupiter and his moons in the 1990s, offer the clearest indication that there is an ocean of water, possibly containing more than twice the volume of all the Earth’s oceans and sea combined, sitting beneath the surface ice on Europa.
The solar-powered craft – solar power being a lot cheaper than nuclear RTGs – will carry a total of nine primary science instruments, with eight confirmed as being:
The Europa Thermal Emission Imaging System (E-Themis) will provide high spatial resolution, multi-spectral imaging of Europa in the mid and far infra-red bands to help detect active sites, such as potential vents erupting plumes of water into space.
The Mapping Imaging Spectrometer for Europa (MIS), an imaging near infra-red spectrometer that will probe the surface composition of Europa, identifying and mapping the distributions of organics (including amino acids and tholins), salts, acid hydrates, water ice phases, and other materials. Scientists hope to be able to relate the moon’s surface composition to the habitability of its ocean.
The Europa Imaging System (EIS), a visible-spectrum wide and narrow angle camera instrument that will map most of Europa at 50 m (160 ft) resolution, and will provide images of selected surface areas at up to 0.5 m resolution.
The Europa Ultraviolet Spectrograph (Europa-UVS) instrument will be able to detect small plumes of material ejected by Europa, and will provide valuable data about the composition and dynamics of the moon’s exosphere.
The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON), a dual-frequency ice penetrating radar instrument designed to characterise and sound Europa’s ice crust from the near-surface to the ocean, revealing the hidden structure of Europa’s ice shell and potential water pockets within.
The Plasma Instrument for Magnetic Sounding (PIMS) working in conjunction with a magnetometer, PIMS is key to determining Europa’s ice shell thickness, ocean depth, and salinity. PIMS will also probe the mechanisms responsible for weathering and releasing material from Europa’s surface into the atmosphere and ionosphere and understanding how Europa influences its local space environment and Jupiter’s magnetosphere.
The Mass Spectrometer for Planetary Exploration (MASPEX) will determine the composition of the surface and subsurface ocean by measuring Europa’s extremely tenuous atmosphere and any surface materials ejected into space.
The Surface Dust Mass Analyser (SUDA), a second mass spectrometer that will measure the composition of small solid particles ejected from Europa, providing the opportunity to directly sample the surface and potential plumes on low-altitude flybys. The instrument is capable of identifying traces of organic and inorganic compounds in the ice of ejecta.
The ninth instrument will be a magnetometer, although this has yet to be sourced – the dedicated instrument, called Interior Characterisation of Europa using Magnetometry (ICEMAG) was cancelled due to spiralling costs and development complications. It will be replaced by a more “off the shelf” system that will be less sensitive than ICEMAG, but the mission team are confident they can compensate for this be more frequent re-calibration operations during the mission.
A pair of composite images of the side of Europa facing away from Jupiter. The rust / brown colour is likely the result of sulphur ejected from Jupiter’s inner moon Io being deposited on Europa by Jupiter’s radiation belt. The lines appear to be cracks in the surface, created by gravitational flexing of the Moon, which causes newer ice to form, indicative of water being forced upwards. Additionally, the yellow staining appears to be sodium chloride – the same as found in our own oceans – deposited on Europa as a result of material being ejected through the cracks. Credit: NASA/JPL / University of Arizona
Early concepts for a Europa mission – as noted above – included a lander – and possibly even a drilling mechanism and an automated submarine that could potentially be dropped under the ice and explore the ocean under it. These ideas were dropped – perhaps wisely – until more is known about the structure and thickness of the surface ice and exactly what lies beneath it. However, Europa Clipper has some additional payload capacity – around 250 kg – and NASA has been seeking ideas on what might be flown; some of the suggestions have included by a payload of supporting CubeSats or a small-scale lander.
While the Europa Clipper mission won’t actually orbit Europa, the multiple fly-bys will enable it to achieve almost global coverage of the moon, allowing for the widest amount of data to be gathered. This will be transmitted back to Earth in the 7-day periods between each close fly-by.
Currently, the mission launch date has yet to be finalised, and this in part depends on the selected launch vehicle. The preferred launcher is NASA’s upcoming Space Launch System (SLS). If used, this would see the mission launched in 2023, with the booster powerful enough to put Europa Clipper on a 3-year direct flight to Jupiter. However, there is no guarantee that SLS will be available in the proposed time frame, so NASA is also looking to use a commercial vehicle such as the SpaceX Falcon Heavy or the ULA Delta IV Heavy. Either of these would allow the mission to launch in 2022, but as they are less powerful than SLS, they would require Europa Clipper use 3 gravity assist manoeuvres, two at Earth and one at Venus, in order to send it on its way, increasing the transit time to Jupiter to 6 years.
The 14 new surface feature names (in yellow) approved for Pluto by the International Astronomical Union on August 8th, 2019. The names in white were approved by the IAU in 2017. Credit: NASA / JHU/APL
On August 8th, 2019, the International Astronomical Union (IAU) approved the names for 14 more significant features on the surface of Pluto, imaged by the New Horizons space vehicle as it flew past the Pluto-Charon system in 2015.
The IAU claimed the authority to officially name or approve the name of planets, dwarf planets, moons, asteroids and planetary features in our solar system during its inaugural General Assembly, held in Rome in May 1922, 3 years after it had been formed by the founding nations of Belgium, Canada, France, Great Britain, Greece, Japan, and the United States, and by which point its membership had grown to 19 nations around the world (today membership stands at 82 nations).
As the sole authority, it means that any names given to things like planetary surface features – such as “Mount Sharp” on the surface of Mars are entirely unofficial, hence why they are referred to in quotes in these Space Sunday articles. The IAU may determine names on things like surface features entirely by itself (as is the case with “Mount Sharp”, which is officially designated Aeolis Mons), or they may take recommendations from other organisations or groups.
In the case of the 14 names first assigned to features on Pluto by the IAU in 2017, the organisation ratified the suggestions made by the New Horizons mission team. Keeping with this “tradition”, the August 8th, 2019 announcement of the 14 “new” names for surface features first employed by the mission team.
The first 14 names to be approved by the IAU (2017) for features on Pluto include the Tombaugh Regio, named for Clyde Tombaugh, who first identified Pluto as a planetary body; the great frozen nitrogen lake of Sputnik Planitia, and the Hillary and Tenzing mountains, named for the two men formally recorded as the first to reach the summit of Mount Everest. Credit: NASA / JHU/APL
All 14 represent people and missions that contributed to the understanding of Pluto and the Kuiper Belt, as well as drawing on figures from mythology and aerospace exploration in general. They cover a range of surface features on Pluto images by the New Horizons vehicle as it dashed through the Pluto-Charon system that include entire regions of the planet and items such as mountain ranges, plains, valleys and craters. They comprise (in alphabetically order):
Alcyonia Lacus, possibly a frozen nitrogen lake, it is named for the “bottomless” lake in the vicinity of Lerna, Greece, and regarded as one of the entrances to the underworld in Greek mythology.
Elcano Montes, a mountain range named for Juan Sebastián Elcano (1476–1526), the Spanish explorer who in 1522 completed the first circumnavigation of the Earth (a voyage started in 1519 by Magellan).
Hunahpu Valles, a system of canyons named for after one of the Mayan Hero Twins who defeated the lords of the underworld in a ball game.
Khare crater honours planetary scientist Bishun Khare (1933–2013), who specialised in the chemistry of planetary atmospheres and who published several seminal papers on tholins, the organic molecules that probably account for the darkest and reddest regions on Pluto.
Kiladze crater is named for Rolan Il’ich Kiladze (1931–2010), who made pioneering early investigations the dynamics, astrometry and photometry of Pluto.
Lowell Regio, is a large region honouring Percival Lowell (1855–1916), founder of the Lowell Observatory and organiser of the search that eventually led Clyde Tombaugh to locate Pluto.
Mwindo Fossae, a network of long, narrow depressions named for the Mwindo Epic of the Nyanga people.
Piccard Mons, a mountain and suspected cryovolcano named for Swiss inventor and physicist and high altitude balloon pioneer, Auguste Piccard (1884–1962).
Pigafetta Montes, a mountain range honouring Antonio Pigafetta (c. 1491–c. 1531), the Italian scholar and explorer who chronicled the discoveries made during the first circumnavigation of the Earth, aboard Magellan’s ships.
Piri Rupes, a range of cliffs named for Piri Reis (also Ahmed Muhiddin Piri c. 1470–1553), an Ottoman navigator and cartographer known for his world map. He also drew some of the earliest existing maps of North and Central America.
Simonelli crater, name after astronomer Damon Simonelli (1959–2004), whose wide-ranging research included the formation history of Pluto.
Vega Terra, a large land mass named after the Soviet Vega 1 and 2 missions, the first spacecraft to fly balloons on another planet (Venus) and to image the nucleus of a comet (1P/Halley).
Venera Terra, named for the Venera missions sent to Venus by the Soviet Union from 1961–1984; they included the first human-made device to enter the atmosphere of another planet, to make a soft landing on another planet and to return images from another planetary surface.
A computer-generated image showing New Horizons’ location in our solar system on August 10, 2019. The green line shows where the vehicle has travelled since its 2006 launch, the red indicates its future path. This perspective is from above the Sun and “north” of Earth’s orbit. Credit: JHU/APl
Since its flyby of the Pluto-Charon system, the New Horizons vehicle has continued its voyage out through the Kuiper Belt. Most of this has been with the vehicle in a state of hibernation to conserve power, however, in January 2019, the craft encountered Kuiper Belt Object (KBO) Ultima Thule, aka 2014 MU69 (see my January 28th 2019 Space Sunday article), and data from that encounter is still being transmitted back to Earth.
Currently, the New Horizons mission is funded until April 2021, and may well be extended beyond that date. The vehicle’s radioisotope thermoelectric generator (RTG), which uses the heat from the radioactive decay of plutonium 238 to provide it with electrical power, is expected to provide sufficient energy for its science instruments until the mid-to-late 2030s. So the science team responsible for the mission at the John Hopkins University Applied Physics Laboratory are currently seeking potential KBO targets the craft could fly by in the mid or late 2020s.
Ultima Thule from a distance of 6,700 km, January 1st, 2019. Credit: NASA / JHU/APL / SwRI
Should the vehicle retain sufficient power for some of its instruments, it may be able to study the outer heliosphere (the “bubble” of space surrounding our solar system and created by the outward flow of energise particles from the Sun) in the late 2030s. If it does, it will add to the data gathered on that distant region of space, 100+ AU from Earth (1 AU = the average distance of the Earth from the Sun) by the Voyager spacecraft.
Parker Solar Probe: One Year In
August 12th, 2019, marked the first anniversary of NASA’s Parker Solar Probe. As I reported in Space Sunday: to touch the face of the Sun, this is an ambitious mission to repeatedly fly through the Sun’s corona – the hazardous region of intense heat and solar radiation in the Sun’s atmosphere that is visible during an eclipse – to gather data that could help answer questions about solar physics that have puzzled scientists for decades.
Named for Eugene Parker, the physicist who first theorised the solar wind, the constant outflow of particles and magnetic fields from the sun, the mission is now into its third orbit of the Sun, and due to make a further close solar approach on September 1st, 2019.
The spacecraft carries four suites of scientific instruments to gather data on the particles, solar wind plasma, electric and magnetic fields, solar radio emission, and structures in the Sun’s corona. This information will help scientists unravel the physics driving the extreme temperatures that make the corona hotter than the “surface” of the Sun – and the mechanisms that drive particles and plasma out into the solar system.
So much information has been gathered by the probe during its first two orbits of the Sun that the mission team on Earth is still analysing it. They hope to have the first results available before the end of the year – not that they are complaining!
We’re very happy. We’ve managed to bring down at least twice as much data as we originally suspected we’d get from those first two perihelion passes.
– Nicky Fox, director of NASA’s Heliophysics Division
An artist’s impression of the Parker Solar Probe swinging around the Sun at a distance of 6.2 million km (3.85 million mi) . Credit: NASA
Nor is that all; the probe’s elliptical 170-188 day orbit means that it has just 11 days per orbit in which to gather data – and these coincide with perihelion, when the craft must withstand temperatures of around 1,370ºC (2,500ºF). To achieve this, the probe is equipped with a 2.3m hexagonal solar shadow-shield that performs three tasks: it absorbs and reflects sunlight away from the vehicle whilst also preventing radiation penetrating its instrument bay and burning-out its circuits and instruments (incident solar radiation at perihelion is approximately 475 times the intensity at low Earth orbit) and also casting a long shadow in which the rest of the vehicle can remain relatively “cool”. Data on the shadow-shield and from within the vehicle as it passes through the corona reveal the shield is working better than anticipated.
So, with another six years of its planned 7-year primary mission, the Parker Solar Probe is set to revolutionise our understanding of the Sun’s corona and the mechanisms powering it.
The data we’re seeing is showing us details about solar structures and processes that we have never seen before. Flying close to the sun—a very dangerous environment—is the only way to obtain this data, and the spacecraft is performing with flying colours.
– Nour Raouafi, Parker Solar Probe project scientist, JHU/APL
June 2011: a pristine assembled MSL Curiosity rover sits within its assembly clean room at NASA’s Jet Propulsion Laboratory prior to being stowed and mounted within its delivery system in preparation for its December 2011 launch to Mars. Credit: NASA/JPL
Seven years ago on August 6th, 2012 at 05:17 UTC, NASA’s Mars Science Laboratory rover Curiosity arrived in Gale Crater on Mars. I’ve covered the progress of the mission throughout (just follow my MSL / Curiosity tag), and those articles in fact gave birth to this Space Sunday column; but it’s been a while since I’ve last updated on things.
Since its arrival on Mars, Curiosity has driven a total of 21 km (13 mi) from its landing point to the base of the crater’s central mound, Aeolis Mons, and has ascended 368 metres (1,207 ft) up the side of the mound, which NASA informally call “Mount Sharp” to its current location.
How Curiosity Reached Mars, (1) cruise stage – provided power and data collection during flight from Earth to Mars; (2) aeroshell protecting rover and skycrane during journey and during entry into the Martian atmosphere, with parachute system (6); (3) the skycrane used to winch the rover down to the ground whilst hovering a few metres in the air; (4) the rover in its stowed configuration; (5) the heat shield that protected the vehicle during its entry into the Martian atmosphere. Credit: NASA/JPL
Along the way, Curiosity has revealed a lot about Mars – including confirmation that Gale Crater has been host to multiple bodies of water during its early life, and that the conditions were suitable for microbial life to have potentially arisen on the planet.
Nor did the rover have to wait to make the discovery: it did so literally within weeks of its hair-raising arrival when it had barely started on its journey and was exploring an ancient riverbed on the floor of Gale Crater (dubbed “Yellowknife Bay”), when analysis of samples gathered revealed all the essential ingredients which – if mixed with water (that once flowed through the riverbed) – might have given life a kick-start and to have been enough to possibly sustain it during the warmer, wet periods of Mars’ early history.
As well as this, Curiosity has revealed much about the ancient conditions on Mars, has found hematite (which requires the presence of water to form), done much to reveal atmospheric processes at work on the planet, and helped track Martian weather and climate processes.
There have been a few causes for concern along the way. Early on in the mission it was revealed that the rover’s six aluminium wheels had suffered more wear and tear than had been anticipated, prompting some changes to the rover’s route as it approached “Mount Sharp”.
Most particularly, the rover’s drill mechanism has had its share of issues, some of which have required changes to how the drill is operated.
However, none of this has really impacted on the rover’s mission – in fact, Curiosity has recently obtained its 22nd drill sample from Mars, as it examines a region the mission team call the “Clay Unit”, one of several closely packed areas with strong differentiators scientists want to examine. Clay forms in the presence of water, and the area has sufficient enough clay deposits to be detected from orbit, and Curiosity has recovered samples with the highest amounts of clay minerals found to date by the mission.
This area is one of the reasons we came to Gale Crater. We’ve been studying orbiter images of this area for 10 years, and we’re finally able to take a look up close.
– Kristen Bennett, U.S. Geological Survey and co-lead for Curiosity’s clay-unit campaign
A panoramic view of “Teal Ridge” in the “Clay Unit” showing sharp differentiations in rock and surface material that suggest the evolution of a lake-like environment. June 18, 2019, the 2,440th Martian day, or sol, of the mission. Credit NASA/JPL
Quite why this particular area is so rich in clay deposits is unclear, but the area is home to complex geologic features, such as “Teal Ridge” and “Strathdon,” a rock made of dozens of sediment layers that have hardened into a brittle, wavy heap. Unlike the thin, flat layers associated with lake sediments Curiosity has studied, these wavy layers in these features suggest a more dynamic environment. Wind, flowing water or both could have shaped this area.
Both “Teal Ridge” and “Strathdon” represent changes in the landscape suggestive of the evolution of the ancient lake environment. This is further exemplified by the area above the “Clay Unit”, and towards which Curiosity is slowly making its way. It’s an area rich is sulphate deposits, indicative that it was drying up or becoming more acidic in ancient times whilst the lower slopes were still rich in water.
The Clay and Sulphate bearing regions on “Mount Sharp” and the proposed path Curiosity is following through them. Credit: NASA/JPL
Cutting down slope through the “Sulphate Unit” is the Gediz Vallis and Ridge, which appears to have been form by water running down “Mount Sharp” at some period after both the Clay Unit and Sulphate Units before spreading into the “Greenheugh Pediment”. This points to the area having seen some considerable changes as a result of climate changes on Mars.
We’re seeing an evolution in the ancient lake environment recorded in these rocks. It wasn’t just a static lake. It’s helping us move from a simplistic view of Mars going from wet to dry. Instead of a linear process, the history of water was more complicated. It’s finally being able to read the paragraphs in a book — a dense book, with pages torn out, but a fascinating tale to piece together.
– Valerie Fox, Division of Geological and Planetary Sciences, Caltech
Curiosity is powered by a radioisotope thermoelectric generator (RTG) that uses a core of plutonium-238. The heat given off by the decay of the isotope is converted into electric voltage by thermocouples and stored within two lithium-ion batteries that directly power the rover’s systems. This ensures the rover obtains constant power during all seasons and through the day and night, with waste heat is also passed through the vehicle’s interior to keep systems and instruments at their operating temperature and without the need for additional electric heating systems.
However, over time, the amount of electrical voltage the RTG can generate decreases. Overall, Curiosity’s RTG is expected to provide sufficient power (100+ Watts) to run all of the rover’s systems for 14 years – so 2019 marks the half-way point. Which is not to say that Curiosity only has seven more years of operations. Rather, it means that in around 7 years power generation is going to fall below the 100 watts mark, and it may become necessary for rationing power between systems on the rover, reducing some of its capacity.
The mission included the first stage of a privately-funded initiative to transfer living DNA to the Moon – a kind of “Noah’s Ark Mark II”, providing a repository from which plants and animals could be regenerated to repopulate the Earth should a catastrophe akin to a flood of biblical proportions overtake the planet. In particular for this first phases of the project, a 30-million-page archive of human history viewable under microscopes, as well as human DNA were carried by the lander in a DVD-like “Lunar Library” – which also includes tardigrades.
The tardigrade. Credit: 3DStock/Shutterstock
Science fiction fans might recognise this name from the television series Star Trek: Discovery. However, far from being the stuff of sci-fi shows and stories, tardigrades are very real (if a lot, lot smaller than their Star Trek “breathren”) and also exceptionally hardy.
Known colloquially as water bears or moss piglets, tardigrades are a phylum of water-dwelling eight-legged segmented micro-animals that can be found almost anywhere on Earth, from the tops of mountains to the bottoms of the oceans, from the tropical stew of rain forests to the frozen wastes of the polar regions. They can survive extremes of temperature and pressure (both high and low), air deprivation, radiation, dehydration, and starvation and exposure to outer space.
The tardigrades were stored dehydrated tardigrade – which puts them into a state of suspended animation – and “encased in an epoxy of Artificial Amber”. In this state, they could in theory be revived if exposed to heat and moisture. But even without these, the tardigrade could survive for years on the Moon – specimens have been recovered after being in a dehydrated state for decades. Such is the design of the unit in which they are stored, those responsible for the project believe it “highly likely” it survived Beresheet’s impact on the surface of the Moon.
Sadly, it is unlikely we’ll ever get to know if this is the case; the crash point for the Israeli lander puts in it in an area of the Moon’s south polar region far removed from any planned destinations for NASA’s Artemis missions, making recovery very unlikely.
Steam Powered Satellites and Autonomous Exploration
Am August press release from NASA reveals the agency has completed tests of what is effectively the world’s first steam-propelled satellite in Earth’s orbit. Admittedly, it not a particularly big vehicle being tested – it is small enough to compete with a box of tissues – but the test is an important step in examining technologies for future automated space exploration.
The test took place on June 21st, 2019, and was part of a coordinated manoeuvre between two CubeSats operating in low-Earth orbit, carried out as part of NASA’s Optical Communications and Sensor Demonstration (OCSD) mission.
The steam-propelled CubeSat in an artist’s impression. Credit: NASA
The two tiny vehicles were orbiting the Earth around 9 km (5.8 mi) apart when they automatically established a radio communications cross-link with one another. One then ordered the other to fire its thruster and close the gap between them. Rather than using a traditional hypergolic propellant or inert gas, both of the CubeSats carry small tanks of water which can be heated to produce steam that is ejected through an engine nozzle to generate propulsion.
This demonstration is important on two counts. The first is that it shows the potential for a series of small satellite drones to command one another to carry out assorted operations entirely independently of control from Earth. Such a group of drones could work cooperatively on a mission – say a survey of the asteroid belt or the icy moons of Jupiter. They could operate in unison, commanding one another, or under the autonomous control of a “mother ship” that could have facilities for storing (and returning) samples to Earth.
The second is that, in using water as a means of propulsion, these vehicles could in theory be easily fuelled and refuelled with water – water which might in turn be obtained from the frozen bodies these craft are exploring.
Demonstrations such as this will help advance technologies that will allow for greater and more extended use of small spacecraft in and beyond Earth-orbit. It is exciting to think about the possibilities enabled with respect to deep space, autonomously organizing swarms of small spacecraft.
– Roger Hunter, programme manager,
NASA Small Spacecraft Technology Programme
Perseid Meteor Shower
Every July / August, the Earth passes through a haze of stellar debris left by Comet 109P/Swift-Tuttle. The result is of this passage is the Perseid meteor shower (called this because they appear to originate from the constellation of Perseus), is one of the brightest meteor displays one can see in the northern hemisphere. The shower tends to last around a month, from July 17th (ish) through to August 24th.
Observing the Perseids in 2019
This year, the peak period for activity should be August 12th and 13th, when between 60 and 100 meteors an hour might be visible streaking across the night sky. In Europe, the best time to see them is after midnight, while America gets it a little easier and earlier. To check time in your location try timeanddate.com, which should give local observation times.
Unfortunately, the moon will be very close to full on the night of the peak, and this will affect the visibility of the fainter meteors. Of course, you’ll also need to be somewhere that’s dark enough to see the night sky without it being blotted too heavily by surrounding Earthly light pollution.
To help people observe the peak period, there are a number of planned livestreams on the web – including the two below.
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