Space Sunday: stainless steel, rovers and explorers

The Starship Hopper under construction at the SpaceX facility at Boca Chica, South Texas. Credit: Austin Barnard/Bloomberg

On Friday, January 11th, 2019, Elon Musk tweeted the first official image of the completed Starship Hopper, the new SpaceX vehicle intended to be an atmospheric test vehicle for the company’s massive Starship vehicle that forms the upper stage of what used to be called the Big Falcon Rocket, the huge lunch system SpaceX is developing.

The vehicle has been under construction at the SpaceX test facility at Boca Chica since December 2018, with the work, surprisingly, being carried out in the open, allows passers-by to photograph and film the work and post to assorted social media, causing something of a stir.

Hopper is not as large as the operational Starship vehicle will be (it is around 40 m / 130 ft tall, compared to Starship’s 52 m / 169 ft height). However, it is the same diameter (9 metres / 29 ft) and highlights the “radical” redesign of the vehicle, such as its more “retro” rocket ship look, and redesigned tail fins (which also double as its landing legs).

The completed Hopper (l) compared to a computer rendering of the vehicle (r), released on January 5th, 2019 by SpaceX CEO Elon Musk. Credit: SpaceX / Elon Musk

The vehicle is intended to be self-powered, using its own engines to fly to altitude, before making a controller descent and landing in the same manner as the full-sized vehicle. In this, its function mimics that of the SpaceX Grasshopper – a specially designed Falcon 9 first stage the company flew in order to learn about the handling characteristics of a Falcon 9 first stage attempting to make a controlled landing after a launch. Flights will initially be to low altitudes, then increase in height.

While Musk’s tweets indicated assembly of the vehicle was finished, further work is required to replace the temporary motors fitted to the vehicle with the flight-capable, methane-fuelled Raptor engines that will power it during ascent and descent. By the time the engines are fitted, the tail fins will have been fitted with shock absorbers to protect the vehicle against the impact of landings, and landing pads.

The “wrinkled” look to the vehicle’s hull is the result of the hull sections being made from a type of stainless-steel alloy which it is believed will be withstand atmospheric entry without the need for complex (and heavier) surface layering, such as reinforced carbon-carbon. Musk has indicated that the skin of the actual Starship will be smooth, and the vehicle will have “a smoothly curving nose section” (and windows).

In terms of the full size vehicle, the first of these is currently being fabricated, together with its booster stage – now simply called “Super Heavy”. Musk has indicated these could be ready as early as June 2019. Once operational, there will likely to be three versions of Starship:

  • The long-duration spacecraft capable of carrying passengers and /or cargo to interplanetary destinations such as the Moon and Mars, to LEO, or between destinations on Earth.
  • A propellant tanker design to refuel other spacecraft – notably the passenger vehicle – whilst in low-Earth orbit.
  • A satellite delivery spacecraft with a large cargo bay and forward door, capable of placing both satellites and other payloads in Earth orbit, or recover items for return to Earth.

The accelerated pace of Starship / Super Heavy development is in keeping with Musk’s goal of flying Japanese billionaire Yusaku Maezawa and an entourage of artists around the moon and back in the mid-2020s. However, it comes at something of a cost. On the same day as Musk tweeted about the Hopper, SpaceX announced it would be laying-off around 10% of its current workforce, some 600 people, as it refocuses efforts on its new launch system and its broadband satellite system.

To continue delivering for our customers and to succeed in developing interplanetary spacecraft and a global space-based Internet, SpaceX must become a leaner company. “Either of these developments, even when attempted separately, have bankrupted other organisations. This means we must part ways with some talented and hard-working members of our team.

– Official SpaceX announcement

To further provide revenue, the company is also mid-way through a US $500 million funding round.

A Steampunk Explorer?

It sounds like something out of a Steampunk novel, but a collaboration between a private space company and the University of Central Florida has shown that a vehicle sent to the asteroids could explore them “indefinitely” using  steam power to propel itself from asteroid to asteroid.

Honeybee Robotics, based in California, and the University of Central Florida (UCF) have developed a vehicle they called World Is Not Enough (WINE), capable of extracting water from asteroids or other planetary bodies, which it then uses as steam to propel itself to its next mining target. This effectively means it – or a vehicle like it – could become capable of indefinite self-refuelling and explore somewhere like the asteroid belt for decades.

By using steam rather than fuel, the World Is Not Enough (WINE) spacecraft prototype can theoretically explore “forever,” as long as water and sufficiently low gravity is present. Credit: University of Central Florida

UCF planetary research scientist Phil Metzger performed extensive computer modelling and simulations over three years in order to show the feasibility of steam propulsion, with the university developing simulated asteroid material that could be used as a feedstock. This work allowed Honeybee Robotics to build the microwave oven sized prototype, with Florida-based Embry-Riddle Aeronautical University providing the steam-powered rocket motors. The complete system was demonstrated for the first time on December 31st, 2018.

It’s awesome. WINE successfully mined the soil, made rocket propellant, and launched itself on a jet of steam extracted from the simulant. We could potentially use this technology to hop on the Moon, Ceres, Europa, Titan, Pluto, the poles of Mercury, asteroids—anywhere there is water and sufficiently low gravity.

– Phil Metzger, UFC, on the WINE prototype demonstration

One of the biggest constraints on robotic missions is the amount of fuel they can carry for manoeuvring. Being able to generate its own rocket propellant in the form of steam frees a vehicle from this constraint. All that is required is a suitable feedstock (and there is ice aplenty to be found throughout the solar system) and electrical energy, which could be supplied via solar panels or a small nuclear RTG “battery”.

Funding for the project has thus far been supported by the NASA Small Business Technology Transfer programme, intended to foster collaboration between universities and small businesses in the development of marketable commercial products. UFC and Honeybee are now seeking partners to continue development of the system.

Continue reading “Space Sunday: stainless steel, rovers and explorers”

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Space Sunday: Ultima Thule and Chang’e 4

An artist’s impression of how the surface of Ultima Thule might look, based on the images and data returned by New Horizons thus far. Credit: NASA

We set a record. Never before has a spacecraft explored anything so far away. Think of it. We’re a billion miles farther than Pluto [and] Just like with Pluto, we could not be happier. What you’re seeing is the first contact binary ever explored by spacecraft: two completely separate objects that are now joined together.

– Alan Stern, New Horizons principal investigator

The astronomical year got off to a flying start on January 1st, 2019 when NASA’ New Horizons vehicle – the same craft that flew by Pluto and Charon and their attendant moons in 2015 – shot past (486958) 2014 MU69, a trans-Neptunian Object (TNO) residing in the Kuiper belt. A relatively tiny object, and dubbed Ultima Thule, it wasn’t even known about when the New Horizons mission launched in January 2006.

As I noted in my previous Space Sunday report, Kuiper Belt objects are of particular interest to planetary astronomers and scientists as they represent the oldest near-pristine material in the solar system, and so could contain many secrets, from how rocky planets formed through to the origins of life. Ultima Thule itself has been of particular interest because data gathered from the Hubble Space Telescope (HST) suggested it might be a binary object due to its apparent brightness fluctuating, suggesting two bodies orbiting one another. However, as New Horizons slipped into the final days leading up to the fly-by, it seemed to report no variance’s in the light reflected by the object.

The space craft reached its point of closest approach to Ultima Thule at 05:33 UT on the morning of January 1st, 2019. However, the nature of the approach, coupled with the huge distance between Earth and the vehicle meant that the first images and data wouldn’t be received for several hours after the probe has passed the object (it takes over 6 hours for radio signals to reach Earth from the vehicle), so at the time of closest approach, scientists and the public had to make do with the images received in the 24 hours preceding it.

Left: a composite image of Ultima Thule taken by New Horizons on December 31st. 2018, at a distance of approx. 1.2 million km revealing the object to most likely be a “contact binary”. Right: a sketch showing the estimated rotation axis of the object relative to New Horizons, helping to explain when no variances in brightness were recorded ahead of the encounter. Credit: NASA / JHU APL / SwRI; James Tuttle Keane

These images, captured while New Horizons was still more than 1 million kilometres (635,000 mi) from Ultima Thule, were enough to confirm that, rather than being either a single elongated object (as suggested by the lack of variance in brightness the probe was recording) or two objects orbiting one another, Ultima Thule is in fact a “contact binary” – objects conjoined after gently colliding with one another, to form a shape initially referred to as a “bowling pin” (this latter changed to “dirty snowman” as clearer images were received). They also revealed why New Horizons wasn’t seeing any brightness variations: whereas Hubble was seeing Ultima Thule from more of an “end on” angle (like a bottle tumbling through the air towards you), New Horizons was approach it more-or-less along its axis of rotation (like standing in front of a slowly turning propeller), so it was always reflecting the same amount of light.

The initial images led members of the New Horizons mission team to call Ultima Thule the “first ever” contact binary object to be explored. However, this might be disputed; the nucleus of comet 67P/Churyumov–Gerasimenko, as seen by ESA’s Rosetta mission, as has two lobes connected by a narrow “neck” region which could mark it as a contact binary.

This first colour photo of Ultima Thule reveals its red colour as seen by New Horizons spacecraft from a distance of 137,000 km (85,000 mi), captured on January 1st, 2019, shortly ahead of the point of closest approach. From left to right: an enhanced colour image, a higher-resolution black and white image, and a composite combining both into a more detailed view. Credit: NASA / JHU APL / SwRI

Nevertheless, there is still something magical about the way the two lobes came together – as a member of the New Horizons team put it, the bump of them joining would have been so gentle, had it been caused by a car bumping your own, it wouldn’t result in any real damage. The lobes themselves are of unequal size; at 19 km (12 mi) across, the larger has been dubbed “Ultima”, while the smaller lobe has been dubbed “Thule”, and is 14 km (9 mi) across. Combined, these give the object an overall length of some 33 km (21 mi). That they came together so gently has already been seen as a confirmation of the pebble accretion theory of planetary formation.

The exterior of both lobes is probably a mix of water, methane and nitrogen ices, doubtless mixed with other elements  / minerals, and the reddish hue revealed in the colour images thus far returned is likely the result of the irradiation of ices on its surface – a process witnessed on Pluto. However, it will not until photographs taken much closer to the object – notably those at closest approach, a mere 3,500 km (2,200 mi) – are received in mid-February, that we’ll have a clear view of the object’s topography.

Following the fly-by, the images received by mission control were taken at distances between 137,000 km (85,000 mi) and 28,000 km (18,000 mi) from the object, and part of the initial data transfer. In all, some 7 Gb of data was gathered, but due to the complexities involved, it will take 20 months for all of it to be received on Earth. In fact, at the time this article was written, and due to the passage of the Sun between the spacecraft and Earth, data transfer has been suspended for five days (January 5th through 10th, 2019) to prevent data loss due to solar interference. Even so, the images that have been received have been enough to not only reveal some of Ultima Thule’s secrets, but to also create new mysteries about it.

Alan Stern, the principal investigator for New Horizons, high-fives Alice Bowman, the mission operations manager at JHU APL, after controllers received a transmission from the spacecraft confirming a successful fly-by of Ultima Thule on January 1st, 2019. Credit: NASA / Bill Ingalls

One of these mysteries is that computer modelling suggests that given the way the two lobes came together, Ultima Thule should have a rate of spin to complete one revolution every 3 or 4 hours. However, data from New Horizons indicates it is spinning far slower: one revolution every 15 hours. So something must have slowed it down – the question is, what?

The most obvious explanation would be the gravitational influence of nearby objects – say two or three small moons orbiting Ultima Thule. However, due to the risk of collision, the space around Ultima Thule was surveyed well ahead of the fly-by, and astronomers are convinced there is nothing orbiting it either beyond 800 km (500 mi) or closer than 160 km (100 mi) – although that does leave a fairly large sphere of space between the two which may yet reveal one or more objects. More will be known on this in late January, when data on New Horizons’ own studies of the space around Ultima Thule should be received by mission control.

Continue reading “Space Sunday: Ultima Thule and Chang’e 4”

Space Sunday: Ultima Thule, Dream Chaser and capsule leaks

An artist’s impression of New Horizons passing Ultima Thule on January 1st, 2019. Credit: Adrian Mann/All About Space

On July 14th, 2015, NASA’s New Horizons vehicle, the front-end of the mission of the same name, made its closest flyby of Pluto and Charon (see Perfectly Pluto for more). Before, during and after the point of closest approach, the vehicle gathered huge amounts of data about Pluto, Charon and their attendant moonlets. Much of the data is still being studied, but in the years since the encounter, New Horizons has revolutionised our thinking about dwarf planets.

Since that time, the space vehicle has been travelling on out into the solar system at a speed of around 49,600 km/h (31,000 mph), and almost as soon as the Pluto flyby had been completed, with New Horizons still having plenty of power thanks to its nuclear batteries, astronomers started looking along its route for a possible follow-up target for examination.

After due consideration of options, a suitable target was selected. officially designated (486958) 2014 MU69, the object is a trans-Neptunian body located in the Kuiper belt. Of an elongated, shape, it is estimated to be around 30 km (18.75 mi), and might be a binary system of objects orbiting one another, although this is currently in doubt.

Discovered by astronomers using the Hubble Space Telescope in June 2014, just over a year before New Horizons reached Pluto, the object was unofficially dubbed “Ultima Thule” (Thule, in Greek and Roman literature, being the farthest north you could go, and “Ultima” being used to indicate “beyond”).  It was selected because of its relative proximity to the probe’s projected course out through the Kuiper belt, allowing it to be reached with minimal course corrections using the probe’s orientation thrusters.

The New Horizons journey. Credit: JHU/APL

The Kuiper belt is a massive ring of stellar objects surrounding the solar system between 30 and 55 AU distance (1 AU – astronomical unit –  being the average distance between the Sun and Earth). It is often regarded as the “outer edge” of our solar system, but the truth is, the solar system extends much, much further. Pluto and Charon are themselves Trans-Neptunian objects within the Kuiper belt.

The region – which might be described more as a doughnut than a belt – contains tens of thousands of objects (with more being discovered on almost a weekly basis). However, such is the volume of space they occupy, most are separated from one another by at least the distance separating Earth from the Sun. They are of great interest to astronomers, as they represent pristine material dating back to the very birth of the solar system, so studying them could tell us a lot more about the place in which we live.

The [Kuiper] belt is analogous to the solar system’s attic. It’s an ancient region, very far from the sun, which has been preserved in a deep freeze. It’s the equivalent of an archaeological dig into the history and formation of the planets. So, scientifically it’s a gold mine, and by going there with a spacecraft and observing KBOs up close, like we’ll be doing with Ultima, we hope to learn a lot about how the early formation stages of the planets took place.

– Alan Stern, New Horizons principal investigator

However, New Horizons won’t have long to study Ultima Thule in detail. If all goes well, the vehicle will blaze past the object on New Year’s Day 2019, at 05:33 GMT), travelling far too fast to slow down. At its closest approach, the probe will be some 3,540 km (2,200 mi) from Ultima Thule, which will appear about as large to it as the full Moon does to observers on Earth. As currently takes 6 hours and 8 minutes for a signal to reach Earth from New Horizons, it means that – as with its Pluto encounter – the probe will be working on an automated basis and pre-programmed commands throughout the encounter.

Simulation of anticipated images the LORRI camera aboard New Horizons vehicle will capture during the close approach to Ultima Thule

Even so, astronomers around the world are eagerly awaiting the encounter, as very little in known about Ultima Thule, and what New Horizions has apparently discovered as it approaches this tiny rock – it is too small to even classify as a dwarf planet – has already piqued interest.

What we know of the trans-Neptunian region is that it’s the leftover remnants of the objects that didn’t make it into being planets. These little rocky and icy worlds were formed in the initial disc of material around the sun, the ones that never grew up into being planets in their own right. Since then, they’ve been sculpted by changes in the orbital positions of the giant planets, particularly Neptune. What we see there today are materials from that initial disc. Some of them are familiar, like water ice and rock, but some of them are unfamiliar, like kitchen cleaning chemicals you have under your sink, in solid form

– Michele Bannister, Outer Solar System Origins Survey, Queen’s University, Belfast

As noted earlier, it had been believed, from data gathered by Hubble, that Ultima Thule was an elongated, possibly binary, object. However, on December 20th, 2018, the New Horizons team reported that the light measured from 2014 MU69 is constant, as would be expected from a spherical body. This disparity between Hubble’s finding and those of New Horizons have yet to be explained.

One issue with the flyby has been the partial US Government shut-down that started on December 22nd, 2018, and which has impacted some of NASA’s public outreach feeds. To compensate, the Applied Physics Laboratory, responsible for designing and building New Horizons, and part of John Hopkins University, has taken over mission briefings and will provide live updates via the JHUAPL YouTube page for flyby events on Monday, December 31st 2018, and Tuesday January 1st, 2019. You can see a full schedule here.

Continue reading “Space Sunday: Ultima Thule, Dream Chaser and capsule leaks”

Space Sunday: recalling Apollo 8

The first image taken by humans of the whole Earth, captured by Bill Anders. It shows the Earth at a distance of 30,000 km (18,750 mi). South is at the top, with South America visible at the covering the top half centre, with Africa entering into shadow. Credit: NASA / Bill Anders (as08-16-2593hr)

2019 marks the 50th anniversary of human beings setting foot on the surface of our Moon. The Apollo programme may have first and foremost been driven out of political need / desires, but it nevertheless stands as a remarkable achievement, given it came n the same decade when a human being first flew in space, and a little under 12 years since the very first satellite orbited the Earth.

To this day, Apollo stands as one of the most remarkable space programmes ever witnessed in terms of scale, cost, and return. It propelled a generation of American school children to pursue careers in engineering, flight, the sciences and more. In all, the Apollo lunar programme flew a total of 11 crews in space between 1967 and 1972, nine of them to the Moon, with two crewed missions to Earth orbit.

After the tragedy of the Apollo 1 fire in January 1967, which claimed the lives of Virgil “Gus” Grissom, Edward White II and Roger B. Chaffee, NASA worked hard to redesign the Apollo Command Module, providing far greater insulation against the risk of fire, as well as altering the vehicle’s atmosphere (from 100% oxygen to a 60/40 oxygen / nitrogen mix) and altering the main hatch so that the crew could escape in the event of a launch pad emergency. In October 1968, the redesigned vehicle, along with its supporting Service Module (together referred to as the Command and Service Module, or CSM) was tested in Earth orbit for the first time by the crew of Apollo 7.

The crew of Apollo 8: (l) James A Lovell Jr, Command Module Pilot; (c) William A. Anders (Lunar Module pilot, although no actual lunar Module was flown); (r) Frank Borman, Mission Commander. This official photograph was taken on November 22nd, 1968, a month before they would orbit the Moon. Credit: NASA

Scheduled for launch towards the end of 1968, Apollo 8 had originally been planned as the first orbital flight test of the CSM and Lunar Module (LM). However, two events encouraged NASA to revisit their plans. Due to continued delays in the delivery of a flight-ready LM, the agency decided to swap the Apollo 8 and Apollo 9 missions and crews around; Apollo 9 would flight-test CSM and LM, once available. Meanwhile, Apollo 8, carrying Frank Borman, Jim Lovell and Bill Anders, and marking the first crewed flight of the mighty Saturn V rocket, would be used in an orbital flight designed to simulate the atmospheric re-entry at the speeds a Command Module would face on a return from the Moon without actually sending the crew to the Moon.

Then, in August and September 1969 photographs captured by US spy satellites suggested the Soviet Union had one of its massive N1 rocket, easily the equal of Saturn V, sitting on a launch pad. With fears that the Soviet Union was perhaps approaching the point where it could launch a crewed mission to the Moon, Apollo 8 was further revised and Borman, Lovell and Anders were informed they’d be spending Christmas 1968 where no other person had spent Christmas before: in orbit around the Moon, allowing them to fully check-out the CSM as it would be flown in an actual lunar landing mission.

Apollo 8 on the launch pad the night before launch. Credit NASA

So it was that on Saturday, December 21st, 1968, Borman, Lovell and Anders were strapped into their seats atop the 110.6 metre (363 ft) tall Saturn V, about to undertake the longest journey ever undertaken by humans up until that point in time. At 07:51 local time (12:51 UTC) the five massive F-5 engines of the rocket’s first stage thundered into life, slowly lifting the 2,812 tonne (US 3,100 short tons) vehicle into the sky.

On reaching orbit, the CSM still attached to the Saturn V’s third stage, spent some 2 hours and 30 minutes in orbit while the crew performed a final check of their systems. Then the S-IVB motor was re-started, and in five minutes accelerated the vehicle from 7,600 to 10,800 metres per second (25,000 to 35,000 ft/s), pushing it away from Earth and on course for the Moon. With TLI – Trans-Lunar Injection successfully completed, the crew separated the CSM and rotated it to photograph the expended third stage, still following behind.

The Apollo 8 S-IVB third stage, imaged from the Command module, shortly after separation. The object at the forward end of the rocket stage is a Lunar Module Test Article, a dummy payload carried in place of an actual Lunar Module. Credit: NASA (from official image AS8-16-2583)

After a mid-course correction, and around 55 hours and 40 minutes after launch, the crew of Apollo 8 became the first humans to enter the gravitational sphere of influence of another celestial body as the effect of the Moon’s gravitational force on the vehicle had become stronger than that of the Earth. Nine hours later, the crew performed the second of two mid-course corrections using the CSM’s reaction control system, bringing them to within 115.4 km (71.7 m) of the lunar surface and oriented ready for a burn of the Service Module’s main motor to slow them into lunar orbit.

Continue reading “Space Sunday: recalling Apollo 8”

Space Sunday: InSight, space and interstellar space

InSight on Mars, December 6 2018, on Flickr
InSight’s first full selfie on Mars, captured on December 6th, 2018 (Sol 10) and released on December 11th. It displays the lander’s solar panels and deck. On top of the deck are its science instruments, weather sensor booms and UHF antenna. Credit: NASA/JPL.

It’s been a further busy week for NASA’s InSight Lander as it starts to get down to business. In particular, the rover has been further exercising its robot arm and preparing for the start of operations – work that has involved surveying its local surroundings.

The week started with NASA releasing InSight’s first “selfie”, a mosaic of 11 images captured by the Instrument Deployment Camera (IDC), located on the elbow of the lander’s robotic arm. Clearly visible in the completed image is the copper-coloured seismometer that will be placed on the surface of Mars to listen to the planet’s interior with its silver protective dome just behind it. Also visible is the black boom of the robot arm rising mast-like.

The IDC is one of two camera systems on InSight, but the only one that is fully mobile. It will be used in conjunction with the Instrument Context Camera (ICC), fixed to the lander’s hull, to correctly place the surface instruments of the SEIS seismometer and the HP3 drilling mechanism on Mars.

The static nature of the ICC means that placement of the surface instruments is limited to an arc directly in front of the lander, and as well as taking selfies, InSight has been using the IDC to survey this area from above.

InSight on Mars, December 1 2018, on Flickr
A mosaic 52 individual images captured by the IDC of the ground directly in front of the lander. It shows the area where the spacecraft will eventually set its science instruments, with the lavender line marking the preferred area for placing SEIS and HP3. Credit: NASA/JPL

Deployment of these two instruments will take time. While operations will start in the coming week, they will likely take around two months to complete. The SEIS will be deployed first. This will be a complex task, placing the unit on the surface first, followed by its protective cover, designed to prevent the Martian wind and atmospheric changes affecting the readings the seismometer takes of the planet’s interior.

If all goes according to plan, the HP3 will be deployed in around mid-January. It will commence operations as soon as possible after deployment. However, it will be an extended process before the instrument starts to deliver on its science goals. This is because the self-hammering heat probe within HP3 – nicknamed the mole – has to “drill” its way some 5 metres (16ft) below the Martian surface. However, it will take time because the probe must pause periodically to release a burst of heat that will help it determine the nature of the material around it and possible hazards below it.

They were speaking about the seven minutes of terror on landing, now I’m saying we have two months of terror in front of us when we penetrate into the surface. The drilling mechanism relies on pushing aside dirt. Smaller rocks it can either push aside or burrow around, but a large rock – 1 metre [3ft] in diameter or so – would stymie the probe’s drilling mechanism. 

– Tilman Spohn, of the German space agency DLR, and HP3’s principal investigator

In particular, the effectiveness of HP3 depends on how deeply it penetrates the regolith.

InSight on Mars, December 1 2018, on Flickr
Three images captured by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter, released on December 13th, 2018. Left: the lander’s aeroshell and parachute. Right: the heat shield, discarded after EDL and ahead of parachute deployment on November 26th, 2018. Centre: InSight itself with a surrounding ring of regolith blasted by the lander’s landing motors. The teal colour is not genuine, but the result of sunlight being reflected off of the lander and its parts saturating the HiRSE imaging system. Credit: NASA/JPL

The less we penetrate, the worse it will be. If it’s just 1 m (3 ft) or so deep, the team will need to rely on more intensive modelling. But if it reaches 3 m (10 ft), which should occur around mid February, the team will be pleased — and if it can reach the full depth of 5 m (16 ft) around March 10th or so, all the better.

– Tilman Spohn

The survey of the landing site has helped confirmed that despite early misgivings when InSight first touched-down, the area occupied by the lander is about as free from rocks and possible surface hazards for SEIS and HP3 as might have been possible to find.

Virgin Galactic Reaches Space with VSS Unity

On December 13th, 2018, Virgin Galactic carried out a supersonic flight test that carried VSS Unity into space for the first time – at least according the NASA’s and the US Air Force’s reckoning. The success of the flight takes Virgin Galactic closer to taking paying customers on the six-passenger rocketplane, which is about the size of an executive jet, on sub-orbital flights into space.

Virgin Galactic’s WhiteKnightTwo carrier aircraft VMS Eve, with VSS Unity slung beneath it, takes to the air from the Mojave Air and Space Port in the early hours of the morning, local time, on December 13th, 2018. Credit: Virgin Galactic

Unity, also referred to as SpaceShipTwo, was carried aloft by its mothership, WhiteKnightTwo from the Mojave Space Port to an altitude of 13,100 metres (43,000 feet). It was then dropped from the carrier jet, allowing the crew of two, Mark “Forger” Stucky and former NASA astronaut Rick “CJ” Sturckow, to ignite the single rocket motor. Burning for 60 seconds,  the motor allowed Unity to start a rapid climb and achieved Mach 2.9, nearly three times the speed of sound.

After engine cut-out, the vehicle continued to climb for a further minute, reaching an altitude of 82 km (51 miles) – enough to put it across the line NASA and the US air Force consider to be the edge of space relative to Earth (80 km / 50 mi above sea level).

A dramatic shot of Unity, having been released by Eve, igniting its rocket motor at the start of a climb from 13 km to 82 km in just 2 minutes.

Once Unity reached apogee, the two pilots were afforded some brief moments of microgravity. They then “feathered” the tail booms, causing the vehicle to gently fall back into the denser atmosphere like a shuttlecock. Once air density was sufficient, the tail sections returned to their “regular” position, allowing the vehicle to achieve unpowered aerodynamic flight, landing back at Mojave Air and Space Port at 08:14 local time (16.14 UTC), with the flight from the drop to the landing lasting 14 minutes in total.

While NASA and the US Air Force view the edge of space being at 80 km, the Fédération Aéronautique Internationale (FAI), the international standard-setting and record-keeping body for aeronautics and astronautics, officially place the boundary between atmosphere and space – called the Kármán line – at 100 km (62 mi; 330,000 ft). Nevertheless, the flight is enough for Stucky to gain his astronaut wings, and for Virgin Galactic to talk in terms of commencing passenger-carrying operations in the near future.

The view from the cockpit at 82 km above the Earth. Credit: Virgin Galactic

Continue reading “Space Sunday: InSight, space and interstellar space”

Space Sunday: hearing Mars, looking at Bennu and roving the Moon

One of InSight’s 2.2 metre (7-ft) wide solar panels was imaged by the lander’s Instrument Deployment Camera fixed to the elbow of its robotic arm. Credit: NASA/JPL

It’s always a remarkable time when a new mission arrives on or around another planet in our solar system, so forgive me if I once again kick-off a Space Sunday with NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, which touched down on Mars just 10 days ago.

Over the course of the last several days, NASA has been putting the lander’s 1.8 metre (6 ft) long robot arm through its paces in readiness for operations to commence. The arm has multiple functions to perform, the most important of which is to place two major science experiments on the surface of Mars. The arm is also home to one of the two camera systems on the Lander.

InSight’s deck partially imaged be the IDC on the lander’s robot arm. Credit: NASA/JPL; annotations: Inara Pey

Very similar to the Navcam systems used by both Opportunity and Curiosity, the camera is called the Instrument Deployment Camera (IDC). It is mounted above the arm’s “elbow” and has a 45-degree field of view. As well as offering a first-hand view of everything the robot arm is doing, IDC can provide colour, panoramic views of the terrain surrounding the landing site.

The arm hasn’t as yet been fully deployed, but in being put through its paces, it has allowed the IDC to obtain some tantalising views of both the lander and its surroundings.

Left: a view of the ground scoop on the robot arm, again seen with the grapple stowed. Note this image was captured with the protective dust cover still in place over the camera lens. Right: a view of InSight’s deck. The copper-coloured hexagonal object is the protective cover for the seismometer, and the grey dome behind it is the wind and thermal shield which will be placed over the seismometer after its deployed. The black cylinder on the left is the heat probe, which will drill up to 5 metres into the Martian surface. Image: NASA/JPL

Some powering-up of science systems has also occurred, notably Auxiliary Payload Sensor Systems (APSS) suite. The air pressure sensors immediately started recording changes in air pressure across the lander’s deck indicative of a wind passing over InSight at around 5 to 7 metres a second (10-15mph). However, the biggest surprise can from the seismometer designed to listen to the interior of Mars.

As this was tested, it started recording a low-frequency vibration in time with the wind recordings from APSS. These proved to be the wind blowing over the twin 2.2-metre circular solar panels, moving their segments slightly, causing the vibrations, which created a sound at the very edge of human hearing. NASA later issued recordings of the sounds, some of which were adjusted in frequency to allow humans to more naturally “hear” the Martian wind.

The InSight lander acts like a giant ear. The solar panels on the lander’s sides respond to pressure fluctuations of the wind. It’s like InSight is cupping its ears and hearing the Mars wind beating on it.

– Tom Pike, InSight science team member, Imperial College London

Once on the surface of Mars and beneath its protective dome, the seismometer will no longer be able to hear the wind – but it will hear the sound of whatever might be happening deep within Mars. So this is likely to be the first of many remarkable results from this mission.

To Touch an Asteroid

NASA’s OSIRIS-REx (standing for Origins, Spectral Interpretation, Resource Identification, Security – Regolith Explorer), launched in September 2016, has arrived at its science destination, the near-Earth asteroid Bennu, after a journey of two billion kilometres.  It will soon start a detailed survey of the asteroid that will last around  year.

Bennu as seen by OSIRIS-REx. Credit: NASA

Bennu, which is approximately 492 m (1,614 ft) in diameter, is classified as a near-Earth object (NEO), meaning it occupies an orbit around the Sun that periodically crosses the orbit of Earth. Current orbital predictions suggest it might collide with Earth towards the end of the 22nd Century.

To this end, OSIRIS-REx will analyse the thermal absorption and emissions of the asteroid and how they affect its orbit. This data should help scientists to more accurately calculate where and when Bennu’s orbit will intersect Earth’s, and thus determine the likelihood of any collision. It could also be used to better predict the orbits of other near-Earth asteroids.

Bennu is primarily comprised of carbonaceous material, a key element in organic molecules necessary for life, as well as being representative of matter from before the formation of Earth. Organic molecules, such as amino acids, have previously been found in meteorite and comet samples, indicating that some ingredients necessary for life can be naturally synthesized in outer space. So, by gaining samples of Bennu for analysis, we could answer many questions on how life may have arisen in our solar system – and OSIRIS-REx will attempt to do just that.

Towards the end of the primary mission, OSIRIS-REx will be instructed to slowly close on a pre-selected location on the asteroid, allowing a “touch and go” sampling arm make contact with the surface for around 5 seconds. During that moment, a burst of nitrogen gas will be fired, hopefully dislodging dust and rock fragments, which can be caught by the sampling mechanism. Up to three such sample “hops” will be made in the hope that OSIRIS-REx will gather between 60 and 2000 grams (2–70 ounces) of material. Then, as its departure window opens in March 2021, OSIRIS-REx will attempt a 30-month voyage back to Earth to deliver the samples for study here.

Continue reading “Space Sunday: hearing Mars, looking at Bennu and roving the Moon”