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”

Space Sunday: InSight, MarCO and privately to the Moon

A simulation of InSight touching down on Mars using its 16 rocket motors. Credit: NASA

On Monday, November 26th, 2018, the latest in a series of NASA missions, the InSight lander – built with international cooperation -, arrived on the surface of Mars.

As noted in my previous Space Sunday report, confirmation that InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) had safely arrived could only be received by mission control at NASA’s Jet Propulsion Laboratory (JPL) after the team there had endured the “seven minutes of terror”, more officially known as the Entry, Descent and Landing (EDL) phase of its journey, the time when the vehicle would enter Mars’ atmosphere and hopefully make a reasonably soft-landing on the planet’s surface.

While undeniably tense, when it came to it – and watched live via social media,  and assorted web broadcast channels put out by NASA – EDL was completed flawlessly. After separating from is cruise element around 7 minutes prior to EDL, InSight, protected by its heat shield and aeroshell, entered the upper reaches of the Martian atmosphere almost precisely on schedule, where over a 4-minute period, the frictional heat created by is passage helped decelerate it from an initial entry velocity of 19,800 km/h (12,300 mph) to 1,400 km/h (860 mph). At this point, telemetry once again being relayed, the supersonic braking parachute was been deployed.

After this things moved quickly: the heat shield was jettisoned from under the lander, which itself dropped free of the parachute and conical aeroshell, using its 16 rocket motors to achieve a “soft” landing on the surface of Mars – travelling at just 8 km/h (5 mph). A video compressing the seven minutes into just over a minute and a half captures the landing – and the joy at mission control (not the celebratory handshake at 1:19!).

It had been anticipated that the first “official” confirmation that InSight had arrived safely would be a “beep” sent directly to Earth from the lander’s X-band radio – and this might be followed a few minutes later by a photograph taken by the lander. As it turned out, and thanks to two tiny CubeSats – of which  more in a moment – it was the photo that arrived first. Grainy and indistinct due to it being taken by a camera still with its protected lens cap in place (itself splattered with dust), it shows a rocky surface and a tightly curved horizon – caused by the camera still being in its stowed configuration.

Side-by-side: (l) the first image returned by InSight using the lander-mounted, Instrument Context Camera (ICC), still with its dust cap in place – note the lander’s leg in the lower right corner. (r) a photo captured by the robot-arm mounted Instrument Deployment Camera (IDC), also taken with the lens cap in place, as the arm is exercised on November 30th, 2018. Credit: NASA/JPL

Initially after landing, InSight was operating on battery power whilst awaiting the dust to settle out of the atmosphere so the two circular solar panels could be deployed. This occurred some 30 minutes after touchdown, with the panels proving so efficient that . So efficient are these panels that during their Martian Sol of operation, they set a new record for power generation: 4,588 watt-hours – well over the 2,806 watt-hours generated in a single Sol by the “nuclear powered” Curiosity.

The efficiency of InSight’s solar arrays will deteriorate over time – the result of general wear-and-tear and the influence of dust that will inevitably accumulate on them – but the power levels have been more than enough for the lander to start flexing its muscles – including testing its robot arm, which is essential to it being able to place key experiments on the surface on Mars.

A computer simulation of InSight deploying its solar arrays. Credit: NASA

It is going to be early spring 2019 before InSight is fully involved in its science mission. There are a lot of equipment check-outs and calibration test to be undertaken, as well as the surface deployment of key instruments. However, there have been some external concerns raised over how well InSight will fulfil its science objectives. As data started coming back from the lander, it was noted that it had touched down in a shallow impact crater, almost completely filled by sand and dust (such craters being known as “hollows” on Mars), which has given InSight a 4-degree tilt.

Overall, the lander can in theory operate with up to a 15-dgree cant (the result of one of this three landing legs coming down on a boulder, for example), but here is a worry about how the tilt may impact placing the Seismic Experiment for Interior Structure (SEIS) and HP3, the Heat Flow and Physical Properties Package, on the surface of Mars, and how the material filling the hollow might affect the operation of HP3’s “mole”, which is designed to burrow into subsurface rock and measure the heat flow from the centre of the planet.

Computer simulation of Insight Placing the Seismic Experiment for Interior Structure (SEIS) experiment and its dust cover on the surface of Mars. Credit: NASA/JPL

Nevertheless the mission team remain in a positive mood and are delighted with both the landing and the first few days of operations.

We couldn’t be happier. There are no landing pads or runways on Mars, so coming down in an area that is basically a large sandbox without any large rocks should make instrument deployment easier and provide a great place for our mole to start burrowing.

– InSight project manager Tom Hoffman

Further examination of the lander’s surroundings will be made once the dust covers have been ejected from the on-board cameras, something that should happen in the next few days. This work will include a careful study of the ground to determine the best placement for SEIS and HP3, as well as a general surveying of the location, which in the initial images, appears a lot less rock-strewn than other locations visited by landers and rovers.

We are looking forward to higher-definition pictures to confirm this preliminary assessment. If these few images—with resolution-reducing dust covers on—are accurate, it bodes well for both instrument deployment.

– Bruce Banerdt, InSight principal investigator

I’ll have more on InSight as the mission develops.

Continue reading “Space Sunday: InSight, MarCO and privately to the Moon”

Space Sunday: Mars roundup

via Associated Press

NASA’s INterior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, launched in March 2018, is due to land on Mars on November 26th, 2018. Managed by NASA’s Jet Propulsion Laboratory, the mission is intended to study the internal structure of the planet, and in doing so it could bring new understanding of the Solar System’s terrestrial planets — Mercury, Venus, Earth, Mars and the Moon.

The lander is based on the design used for NASA’s Mars Phoenix lander, which successfully arrived on Mars in 2008, using circular solar arrays to generate power for its systems and instruments. As with the Phoenix Lander, InSight is designed to operate for a Martian year once on the surface of Mars, with an initial primary mission period of 90 days.

As a static lander, InSight will use a range of instruments to study the deep interior of Mars. Two of the principle instruments in this investigation are the Seismic Experiment for Interior Structure (SEIS) and HP3, the Heat Flow and Physical Properties Package, both of which will be placed in direct contact with the surface of Mars after touch-down.

An artist’s impression of InSight on Mars, showing the SEIS package deployed. Credit: NASA / JPL

Developed by the French Space Agency (CNES), with the participation of the Institut de Physique du Globe de Paris (IPGP), the Swiss Federal Institute of Technology (ETH), the Max Planck Institute for Solar System Research (MPS), Imperial College, Institut supérieur de l’aéronautique et de l’espace (ISAE) and JPL, SEIS is a sensitive instrument designed to do the work of an entire network of seismographs here on Earth.

It will measure seismic waves from marsquakes and meteorite strikes as they move through the planet. The speed of those waves changes depending on the material they’re travelling through, helping scientists deduce what the planet’s interior is made of. Seismic waves come in a surprising number of flavours; some vibrate across a planet’s surface, while others ricochet off its centre and they also move at different speeds. Seismologists can use each type as a tool to triangulate where and when a seismic event has happened.

Such is the sensitivity of SEIS, it can sit in one place and listen to the entire planet and detect vibrations smaller than the width of a hydrogen atom. It will be the first seismometer to be directly placed on the surface of Mars, where it will be thousands of times more accurate than seismometers that sat atop the Viking landers.

Artist’s illustration of InSight’s Seismic Experiment for Interior Structure (SEIS) instrument on the Red Planet’s surface. Credit: NASA TV/JPL

Also, because of the instrument’s sensitivity, SEIS will be protected from the local weather by a protective shell and skirt, both of which will stop local wind interfering with the instrument. In addition, it will be supported by a suite of meteorological tools to characterise atmospheric disturbances that might affect its readings.

HP3 has been provided by the German Aerospace Centre (DLR). It is a self-penetrating heat flow probe,  more popularly referred to as a “self-hammering nail” with the nickname of “the mole”. Once deployed on the surface of Mars, it will burrow 5 m (16 ft) below the Martian surface while trailing a tether with embedded heat sensors every 10 cm (3.9 in) to measure how efficiently heat flows through Mars’ core, revealing unique information about the planet’s interior and how it has evolved over time.

The “self-hammering nail” description comes from the spike, or “mole” at the end of the tether. A mechanism within it  will allow it to propel itself into the Martian regolith and down through the rock beneath it.

Diagram of HP3, showing the deployment system, the “mole” and tether. Credit: DLR

Once fully deployed, HP3 will be able to detect heat trapped inside Mars since the planet first formed. That heat shaped the surface with volcanoes, mountain ranges and valleys. It may even have determined where rivers ran early in Mars’ history.

On arrival at Mars, InSight will enter the planet’s atmosphere and land on Elysium Planitia, around 600 km (370 mi) from where the Curiosity rover is operating in Gale Crater. I’ll have more on the mission around the time InSight makes its landing on Mars.

Continue reading “Space Sunday: Mars roundup”

Space Sunday: saving Oppy, ISS leaks, and humans to Mars

NASA’s MER rover, Opportunity (MER-B) arrived on Mars in January 2004. It has been in a “sleep” mode since the start of June 2018, as a result of a globe-spanning dust storm on Mars. Credit: NASA/JPL

NASA has announced it will undertake a 45-day campaign to try to re-establish contact with its long-lived Mars Exploration Rover (MER) Opportunity. in the wake of contact being lost was a globe-spanning dust storm started to grip Mars in June 2018.

After running its course for almost three months, the storm is now abating, and whilst not the biggest storm seen on Mars since “Oppy” arrived there it the start of 2004, it is one of the most intense in terms of the amount of dust thrown up into the Martian atmosphere.

Contact with the rover was lost in early June 2018. With sunlight barely able to penetrate the dust in the air, it is thought the rover went into hibernation to conserve battery power – terminating contact with Earth in the process.

The attempt to re-establish communications will commence once the tau in the region where “Oppy” is located has dropped below 1.5. Tau is the term used to measure the opaqueness of the dust in the Martian atmosphere, and it is usually around 0.5. Opportunity requires a tau of below 2.0 to avoid triggering its sleep mode, and by early June the value had reached 10.8 – making this dust storm the densest the rover has ever encountered during its fourteen years on Mars.

As a solar-powered vehicle, there are a number of risks Opportunity faces during a long duration dust storm. The first is that as the batteries cannot be charged, they could run out of sufficient power required to keep the rover’s sensitive electronics warm – although this is partially mitigated by the fact that during a storm like this, the heat normally radiated away by the planet gets trapped in the dusty atmosphere, raising the ambient temperature and thus offsetting the amount of power the rover needs to use to keep itself warm.

How the dust storm progressed. Taken 15 days apart through the same telescope and viewing the same face of Mars. On the left, taken on June 8th and the storm started to rise, features such as Syrtis Major ( the dark India-shaped marking below centre) are visible. On the right, taken on June 23rd, they are almost totally obscured by dust. Note that south is top the top of both images. Credits: Damian Peach (left) / Christopher Go (right)

To other points of concern with the rover are the potential for a clock failure, or what is called an “uploss” recovery being triggered. Opportunity’s on-board clock allows the rover to track when an orbiting satellite – vital for relaying signals from the rover to Earth – is above the local horizon, allowing Opportunity to make contact with Mission Control. If it has failed or now has an incorrect reading as a result of power fluctuations, “Oppy” might not be easily able to establish contact with Earth by itself. An “uploss” recovery is triggered when the rover has failed to establish contact with Earth for an extended period. There is a concern that if the rover didn’t enter its hibernation state correctly, the lack of any communications might have triggered this mode, forcing the rover to continuously re-try different methods to receive a signal from Earth, using up its power reserves.

The 45-day campaign will be a pro-active attempt to re-establish contact with “Oppy” from Earth by sending commands out to it. However, if there is no response from the rover, a grim warning was given in the announcement:

If we do not hear back after 45 days, the team will be forced to conclude that the Sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover. At that point, our active phase of reaching out to Opportunity will be at an end.

– John Callas, Opportunity project manager, NASA Jet Propulsion Laboratory

This has drawn some sharp criticism from former members of the MER team, particularly those who worked with Opportunity. They point out that when communications were lost with the other MER vehicle, Spirit, in 2010, NASA spent 10 months trying to re-establish contact. In response to the criticism, NASA state that the 45-day period has been dictated by the decreasing amount of sunlight the rover is receiving as winter approaches, requiring the rover to start conserving power once more, but they will continue to listen for any attempts by the rover to re-establish communications after 45 day campaign has come to an end – they just won’t continue to try to make the connection pro-actively.

Even if communications are re-established, it doesn’t necessarily mean “Oppy” is out of danger; there is a chance that the storm has caused the rover to use its batteries for so long without charge, then may not longer have the capacity to charge correctly or to efficiently retaining their charge – either of which could severely impact further operations for the rover, and require careful assessment.

Soyuz Pressure Leak at the ISS

A Soyuz vehicle suffered a minor loss of cabin pressure whilst docked at the International Space Station (ISS), causing a bit of a fuss in some sectors of the media.

At around 19:00 Eastern Standard Time on August 29th, 2018, ground controllers noted a loss of atmospheric pressure in the orbital module of a Soyuz MS-08 docked to the station. While some media outlets reported the ISS crew “scrambled” to locate and patch the source of the pressure loss, the drop was so slight mission controllers decided to allow the 6-man crew to continue their sleep period aboard the station, and did not inform them of the issue until they were woken up at their scheduled time.

A Soyuz vehicle docked with the ISS (a second Soyuz is just visible, top reight of this image). The pressure leak occurred in the spherical orbital module directly attached to the space station. Behind this is the earth return module (and primary compartment for cosmonauts and astronauts when flying Soyuz) with the white section at the rear, with the solar panels, is the vehicle’s propulsion and power module. Credit: NASA / Roscosmos.

The leak was ultimately traced to a 2mm hole through the skin of the Soyuz module. A temporary fix was made using tape while the crew awaited instructions from Earth on how best to affect a more permanent repair. This actually highlighted a difference in approach between American astronauts and engineers and their Russian counterparts in handling situations.

The Americans – including Expedition 56 Commander Drew Feustel – were keen to explore and test options on Earth before determining on a curse of action out of concern that if options were not tested, then a repair could result in additional damage to the Soyuz. Russian engineers, however, proposed just the one approach to making the repair, and ordered the two Russian cosmonauts on the ISS – Oleg Artemyev and Sergei Prokopyev – to make the repair without any Earth-based testing, handling the situation entirely in Russian and using an interpreter to keep NASA personnel appraised of progress.

After completing the work, Artemyev and Prokopyev reported bubbles forming in the patch, but were instructed to leave it in place to harden over 24 hours. At the time of writing, the path appears to be holding, with no further leaks reported. The damaged Soyuz had been scheduled to make a return to Earth in December 2018 (each vehicle generally spending around 6 months berthed at the ISS alongside another Soyuz so they can be used as “lifeboats” by a station crew should they have to abandon the station for any reason), but as a result of the incident, mission controllers are contemplating using the vehicle in October, when three of the current ISS crew are due to return to Earth.

As the leak occurred in the Soyuz orbital module, it does not pose a threat to a crew: the module is only used during the time a Soyuz is en route to the ISS to give the crew a little more space. On a flight back to Earth the module is jettisoned along with the power and propulsion module, leaving the crew to return in the “mid-ships” Earth return capsule.

The cause of the leak is still being investigated, but suggestions are that it may have been a MMOD – a MicroMeteoroid (tiny piece of orbiting rock weighing less than a gramme but travelling at high-speed) or a piece of Orbital Debris (tiny fragment of debris from a space mission). Such strikes have occurred with the ISS in the past, but if this is the cause of the Soyuz leak, it will be the first time such a strike has directly resulted in a loss of atmospheric pressure either aboard the station or a vehicle docked with it, something that will add to concerns as to the amount of natural and human-made debris circling Earth.

Continue reading “Space Sunday: saving Oppy, ISS leaks, and humans to Mars”