Space Sunday: Voyager at 40

Voyager: 40 years on. Credit: NASA

August 20th 2017 marks the 40th anniversary of the launch of Voyager 2, which with its sister craft Voyager 1 (launched on September 5th, 1977) are humanity’s furthest-flown operational space vehicles, with Voyager 1 being the most distant human made object from Earth, at some 140 AU (AU= astronomical unit, the average distance between the Earth and the Sun; 140 AU equates to about 20.9 billion kilometres / 13 billion miles).

Despite being so far away from Earth, both craft are still sending data back to Earth as they fly through the interstellar medium in the far reaches of the solar system (the Pioneer 10 and Pioneer 11 craft which pre-date the Voyager programme by some 5 years, ceased transmissions to Earth in January 2003 and September 1995 respectively, although Pioneer 10 is the second most distant human made object from Earth after Voyager 1).

The Voyager programme stands as one of the most remarkable missions of early space exploration. Originally, the two vehicles were to be part of NASA’s Mariner programme, and were at first designated Mariner 11 and Mariner 12 respectively. The initial Mariner missions – 1 through 10 – were focused on studying the interplanetary medium and  Mars, Venus and Mercury (Mariner 10 being the first space vehicle to fly by two planets beyond Earth – Venus and Mercury – in 1974). Mariner 11 and Mariner 12 would have been an expansion of the programme, intended to perform flybys of Jupiter and Saturn.

A drawing of the Voyager vehicles. Credit: NASA/JPL (click for full size)

However, in the late 1960s Gary Flandro, an aerospace engineer at the Jet Propulsion Laboratory (JPL) in California noted that in the late 1970s, the outer planets would be entering a period of orbital alignment which occurs once every 175 years and which could be used to throw a series of probes out from Earth, which could then use the gravities of the worlds they encountered to “slingshot” them on to other targets. This led to the idea of a “Grand Tour” mission: sending pairs of probes which could use these gravity assists to fly by Jupiter, Saturn, Uranus, Neptune and Pluto in various combinations.

Funding limitations eventually brought an end to the “Grand Tour” idea, but the planetary alignment was too good an opportunity to miss, and so elements of the idea were folded into the Voyager Programme, which would utilise Mariner 11 and Mariner 12. However, as the mission scope required some significant changes to the vehicles from the basic Mariner design, they were re-designated as Voyager class craft.

(As an aside, the Mariner class is the longest-lived of NASA’s space probe designs; as well as the ten missions of the 1960s and 1970s which carried the design’s name,  the Mariner baseline vehicle – somewhat enlarged – was used for the Viking 1 and Viking 2 orbiter missions to Mars, and formed the basis of the Magellan probe (1989-1994)  to Venus and the Galileo vehicle (1989-2003) which explored Jupiter. And uprated and updated baseline Mariner vehicle, designated “Mariner Mark II”, formed the basis of the Cassini vehicle, now in the terminal phase of its 13-year study of Saturn and its moons.)

Each of the Voyager mission vehicles is powered by  three plutonium-238 MHW-RTG radioisotope thermoelectric generators (RTGs), which provided approximately 470 W at 30 volts DC when the spacecraft was launched. By 2011, both the decay of the plutonium and associated degradation of the thermocouples that convert heat into electricity has reduced this power output by some 57%, and is continuing at a rate of about 4 watts per year.

To compensate for the loss, various instruments on each of the vehicles have had to be turned off over the years. Voyager 2’s scan platform and the six instruments it supports, including the vehicle’s two camera systems, was powered-down in 1998. While the platform on Voyager 1 remains operational, all but one of the instruments it supports – the ultraviolet spectrometer (UVS) – have also been powered down. In addition, gyro operations ended in 2016 for Voyager 2 and will end in 2017 for Voyager 1. These allow(ed) the craft to rotate through 360 degrees six times per year to measure their own magnetic field, which could then be subtracted from the magnetometer science data to gain  accurate data on the magnetic fields of the space each vehicle is passing through.

However, despite the loss of capabilities, both Voyager 1 and Voyager 2 retain enough power to operate the instruments required for the current phase of their mission – measuring the interstellar medium and reporting findings back to Earth. This phase of the mission, officially called the Voyager Interstellar Mission, essentially commenced in 1989 as Voyager 2 completed its flyby of Neptune, when the missions as a whole was already into their 12th year.

A plume rises 160 km (100 mi) above Loki Patera, the largest volcanic depression on Io, captured in March 1979 by Voyager 1. Credit: NASA/JPL

Voyager 2 was launched on August 20th, 1977. Of the two vehicles, it was tasked with the longer of the planned interplanetary missions, with the aim of flying by Jupiter, Saturn, Uranus and Neptune. However, the latter two were seen as “optional”, and dependent upon the success of Voyager 1.

This was because scientists wanted the opportunity to look at Saturn’s moon Titan. But doing so would mean the Voyager craft doing so would have to fly a trajectory which would leave it unable to use Saturn’s gravity to swing it on towards an encounter with Uranus. Instead, it would head directly towards interstellar space.

So it was decided that Voyager 1, which although launched after Voyager 2 would be able to travel faster, would attempt the Titan flyby. If it failed for any reason, Voyager 2 could be re-tasked to perform the fly-past, although that would also mean no encounters with Uranus or Neptune. In the end, Voyager 1 was successful, and Voyager 2 was free to complete its surveys of all four gas giants.

Along the way, both missions revolutionised our understanding of the gas giant planets and revealed much that hadn’t been expected, such as discovering the first active volcanoes beyond Earth, with nine eruptions imaged on Io as the vehicles swept past Jupiter. The Voyager missions were also the first to find evidence that Jupiter’s moon Europa might harbour a subsurface liquid water ocean and to return the first images of Jupiter’s tenuous and almost invisible ring system. Voyager 1 was responsible for the first detailed examination of Titan’s dense, nitrogen-rich atmosphere, and Voyager 2 for the discovery of giant ice geysers erupting on Neptune’s largest moon, Triton. In addition, both of the Voyager vehicles added to our catalogues of moons in orbit around Jupiter and Saturn, and probed the mysteries of both planet’s atmospheres, whilst Voyager 2 presented us with our first images of mysterious Uranus and Neptune – and thus far remains the only vehicle from Earth to have visited these two worlds.

This is the last full planet image captured of Neptune. Taken by Voyager 2 on August 21st, 1989, from a distance of 7 million km (4.4. million mi). A true colour image white balanced to reveal the planet under typical Earth lighting conditions, it shows Neptune’s “Great Dark Spot” and surrounding streaks of lighter coloured clouds, all of which persisted through the period of Voyager 2’s flyby. More recent Hubble Space Telescope images suggest the “Great Dark Spot”, initially thought to be a possible cloud / storm formation, similar to Jupiter’s Great Red Spot, has vanished, leading to speculation that it may have actually been a “hole” in a  layer of Neptune’s layered clouds. Credit: NASA/JPL

The flyby of Neptune also sealed Voyager 2’s future. Scientists were keen to use the flyby of the planet to take a look at Triton, Neptune’s largest moon. However, because Triton’s orbit around Neptune is tilted significantly with respect to the plane of the ecliptic, Voyager 2’s course to Neptune  had to be adjusted by way of a gravitational assist from Uranus and a number of mid-course corrections both before and after that encounter, so that on Reaching Neptune, it would pass over the north pole, allowing it to bent “bent” down onto an intercept with Triton while the Moon was at  apoapsis – the point furthest from Neptune in its orbit – and well below the plane of the ecliptic. As a result, Voyager 2 passed over Triton’s north pole 24 hours after its closest approach to Neptune, its course now pointing it towards “southern” edge of the solar system.

Continue reading “Space Sunday: Voyager at 40”

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Space Sunday: of life elsewhere and launches

Titan’s structure (via wikipedia)

Saturn’s giant moon, Titan, has been a source of speculation of decades. Shrouded in a dense, methane-nitrogen rich atmosphere, potentially harbouring a liquid water ocean beneath its crust, the moon has long be thought to have the conditions in which basic life might arise.

The joint NASA-ESA Cassini-Huygens mission has, over the span of thirteen years, added immeasurably to our understanding of Titan – and to the mysteries of its potential. In doing so, it has also provided us with evidence of processes taking place which are the precursors to the development of life. For example, we know that within Titan’s ionosphere, nitrogen, carbon and hydrogen are exposed to sunlight and energetic particles from Saturn’s magnetosphere. This exposure drives a process wherein these elements are transformed into more complex prebiotic compounds, which then drift down towards the lower atmosphere and form a thick haze of organic aerosols that are thought to eventually reach the surface.

However, while the drivers of the process are known, the nature of the process itself has been something of a mystery – one which an international team of scientists led by the University College London (UCL) think they now understand.  In Carbon Chain Anions and the Growth of Complex Organic Molecules in Titan’s Ionosphere the team identify Titan’s upper atmosphere contains a negatively charged species of linear molecule in Titan’s atmosphere called “carbon chain anions” – which, it has in the past been theorised, may have acted as the basis for the earliest forms of life on Earth.

The molecules were detected by CAPS, the Cassini Plasma Spectrometer, as the vehicle passed through the upper reaches of Titan’s atmosphere on a final flyby before commencing its “Grand Finale” of flights between Saturn and its rings. The discovery came as a surprise, as carbon chain anions are highly reactive, and should not survive long in Titan’s atmosphere. However, what particularly caught the attention of the science team was that the data show that the carbon chains become depleted closer to the moon, while precursors to larger aerosol molecules undergo rapid growth. This suggests a close relationship between the two, with the carbon chains ‘seeding’ the larger molecules – those prebiotics mentioned above – which then fall to the surface.

How complex molecules are thought to form in Titan’s atmosphere. Credit: UCL

“We have made the first unambiguous identification of carbon chain anions in a planet-like atmosphere, which we believe are a vital stepping-stone in the production line of growing bigger, and more complex organic molecules, such as the moon’s large haze particles,” said Ravi Desai, the lead author for the study in a press release from UCL.

He continued, “This is a known process in the interstellar medium – the large molecular clouds from which stars themselves form – but now we’ve seen it in a completely different environment, meaning it could represent a universal process for producing complex organic molecules. The question is, could it also be happening at other nitrogen-methane atmospheres like at Pluto or Triton, or at exoplanets with similar properties?”

With its rich mix of complex chemistry coupled with its basic composition, Titan is something of a planetary laboratory; one which probably mirrors the very early atmosphere surrounding Earth before the emergence of oxygen-producing micro-organisms which started the transformation of our atmosphere into something far more amenable for the advance of life. As such, the discovery of carbon chain anions in Titan’s atmosphere potentially confirms that long-held theory that they help kick-start the life creating processes here on Earth, and suggest conditions on Titan might allow the same to happen there. It also offers insight into how life might start elsewhere in the galaxy.

“These inspiring results from Cassini show the importance of tracing the journey from small to large chemical species in order to understand how complex organic molecules are produced in an early Earth-like atmosphere,” Dr Nicolas Altobelli, ESA’s Cassini project scientist, said in the same press release. “While we haven’t detected life itself, finding complex organics not just at Titan, but also in comets and throughout the interstellar medium, we are certainly coming close to finding its precursors.”

Dream Chaser ISS Flights target 2020 Commencement

Sierra Nevada Corporation (SNC) has confirmed than United Launch Alliance (ULA) will provide the veritable Atlas V booster as the launch vehicle for the Dream Chaser Cargo mini-shuttle, which will be joining fleet of uncrewed vehicles from America, Russia and Japan keeping the International Space Station (ISS) supplied with consumables, equipment and science experiments. The company also indicate that launches of the vehicle could start in 2020.

The Altas V – Cream Chaser Cargo launch configuration. Credit: United Launch Alliance

Dream Chaser was originally conceived to fly crews to and from the ISS as part of NASA’s commercial crew transportation joint venture with the private sector. Four companies vied for contracts to supply NASA with vehicles capable of shuttling up to six personnel to and from the space station. Despite being one of the most advanced of the designs in terms of feasibility and development, the Dream Chaser was not selected for that work, with NASA opting for the SpaceX Dragon 2 vehicle and Boeing’s CST-100 Starliner capsule.

However, support within the US space agency for the Dream Chaser continued, allowing SNC to propose the development of Dream Chaser Cargo, a revised version of the original concept, capable of supplying up to 5.5 tonnes of cargo to the ISS. In January 2016, in renewing its contract with SpaceX (Dragon) and Orbital ATK (Cygnus) for such resupply missions, NASA extended it to include SNC. This was followed a year ago by formal approval being given for Dream Chaser missions to the ISS, which allowed SNC to push ahead with testing of the revised vehicle.

Dream Chaser will launch atop the commercial Atlas V in its most powerful configuration, dubbed Atlas V 552, with five strap on solid rocket motors and a dual engine Centaur upper stage. The cargo vehicle will be held inside a five metre diameter payload fairing with its wings folded. Cargo will be carried both within the vehicle itself and in a support module mounted on the rear of the spacecraft, which will also house a docking adaptor for connecting with the space station. The latter will be supplied to SNC by the European Space Agency, which is also supplying NASA with the Service Module for the Orion multi-Purpose Crew Vehicle.

The Dream Chaser Cargo, built by SNC, and the International Berth and Docking Mechanism, to be supplied to SNC for Dream Chaser flights by the European Space Agency. Credit: SNC

In addition to flying up to 5.5 tonnes to the ISS, Dream Chaser Cargo will be able to return some 2 tonnes of equipment, experiments and other items from the space station to Earth, where it will make a conventional runway landing using the former space shuttle runway at Kennedy Space Centre – or any other suitable landing facility in the United States.

It is expected that Dream Chaser cargo will fly a total of six missions to the ISS between 2020 and 2024, when it is currently anticipated the space station will be decommissioned.

Continue reading “Space Sunday: of life elsewhere and launches”

Space Sunday: ninja space stations, Falcons, Dragons and ET

The cislunar Deep Space Gateway with an Orion Multi-Purpose Crew Module approaching it. Credit: NASA

Lockheed Martin has announced it will build a full-scale prototype of NASA’s proposed Deep Space Gateway (DSG), a space habitat occupying cislunar space. The facility, which if built, will be both autonomous and crew-tended, and is intended to be used as a staging point for the proposed Deep Space Transport NASA is considering for missions to Mars, as well as for robotic and crewed lunar surface missions.

DSG is part of a public-private partnership involving NASA in developing technologies for carrying humans beyond low Earth orbit called Next Space Technologies for Exploration Partnerships (NextSTEP). A Phase I study for the facility has already been completed, and the full-scale prototype will be constructed as a part of the Phase II NextSTEP habitat programme, which will examine the practical issues of living and working on a facility removed from the relative proximity of low Earth orbit, outside of the relative protection of the Earth’s magnetic field and subject to delays of up to 3 seconds in two-way communications.

“It is easy to take things for granted when you are living at home, but the recently selected astronauts will face unique challenges,” said Bill Pratt, Lockheed Martin NextSTEP program manager.

“Something as simple as calling your family is completely different when you are outside of low Earth orbit. While building this habitat, we have to operate in a different mindset that’s more akin to long trips to Mars to ensure we keep them safe, healthy and productive.”

The proposed Gateway, which if built would likely enter service in 2027/2028, will be designed to make full use of the Orion Multi-Purpose Crew Module as its command and control centre, and will also use avionics and control systems designed for the likes of NASA’s MAVEN mission in order around Mars and the Juno mission at Jupiter, which will allow the facility to operate in an uncrewed automated flight mode around the Moon for up to seven months at a time.

NASA’s MPLM mission logo. Credit: NASA / Marshall Space Flight Centre

The core of the prototype will be the Donatello Multi-Purpose Logistics Module (MPLM), originally designed and built for flights aboard the space shuttle and capable of delivering up to nine metric tonnes of supplies to the International Space Station (ISS). Two of these units, Leonardo and Raffaello flew a total of 12 missions to the ISS between 2001 and 2011, with Leonardo becoming a permanent addition to the space station in early 2011. And if film and comic fans are wondering, yes, the modules were all named after a certain band of mutant ninja turtles – hence the MPLM mission logo (right).

Donatello was a more capable module than its two siblings, as it was designed to carry payloads that required continuous power from construction through to installation on the ISS. However, it was never actually flown in space, and some of its parts were cannibalised to convert Leonardo into a permanent extension to the space station. In its new role, Donatello will form the core habitat space for the DSG prototype, and will be used as a testbed for developing the living and working space in the station, which will also have its own power module and multi-purpose docking adapter / airlock unit.

The Phase II development of the DSG is expected to occur over 18 months. Mixed Reality (augmented reality and virtual reality) will be used throughout the prototyping process to reduced wastage, shorten the development time frame and allow for rapid prototyping of actual interior designs and systems. The results of the work and its associated studies will be provided to NASA to help further the understanding of the systems, standards and common interfaces needed to make living in deep space possible.

The DSG is one of two concepts NASA is considering in it attempts to send humans to Mars. The second is the so-called Deep Space Transport (DSH). This is intended to be a large vehicle using a combination of electric and chemical propulsion to carry a crew of six to Mars. It would be assembled at the Deep Space Gateway.

While having a facility in lunar orbit does make sense for supporting operations on the Moon’s surface, when it comes to human missions to Mars, the use of the DSG as an assembly  / staging post for the DST actually makes very little practical sense. Exactly the same results could be achieved from low Earth orbit and without all the added complications of lunar orbit rendezvous. The latter simply adds an unnecessary layer of complexity to Mars missions whilst providing almost no practical (or cost) benefits, and perhaps again demonstrates NASA’s inability to separate the Moon and Mars as separate destinations – something which has hindered their plans in the past.

Musk Walks Back SpaceX Aspirations

SpaceX CEO and chief designer, Elon Musk has walked back on expectations for the initial lunch of the Falcon Heavy booster and on longer-terms aspirations for the Dragon 2 crew capsule.

Musk: a successful maiden flight of the Falcon Heavy “unlikely”. Credit: Associated Press

Speaking at the International Space Station Research and Development Conference held in Washington DC in mid-July 2017, Musk indicated that a successful maiden flight of the Falcon Heavy rocket is extremely unlikely. He also indicated that the company is abandoning plans to develop propulsive landing techniques for the Dragon 2 when returning crews to Earth from the ISS – and to achieve a soft landing on Mars.

Falcon Heavy is slated to be the world’s most powerful rocket currently in operation when it enters service in 2018, capable of lifting a massive 54 tonnes to low Earth orbit – or boosting around 14 tonnes on its way to Mars. Designed to be reusable, the rocket uses three core stages of the veritable Falcon 9 rocket – one as the centre stage, two as “strap on boosters” either side of it.

But computer modelling has revealed that firing all 27 motors on the stages (nine engines apiece) at launch has dramatically increased vibrations throughout the vehicle stack, making it impossible to gauge by simulation whether or not the rocket will shake itself apart without actually flying it. Hence Musk’s statement that the maiden flight of the Falcon Heavy  – slated for later in 2017 – is unlikely to achieve a successful orbit. However, telemetry gathered during the flight – should the worse happen – will help the company more readily identify stresses and issues created by any excessive vibration, allowing them to be properly countered in future launches.

Once Falcon Heavy is fully operational, all three of the core stages are intended to return to Earth and achieve a soft landing just as they do when used as the first stage of a Falcon 9 launch vehicle, and SpaceX is also working to make the upper stage of the Falcon 9 / Falcon Heavy  recoverable as well.

Also at the conference, Musk announced SpaceX will no longer be using propulsive landings for the crewed version of their Dragon 2 space capsule, due to enter operations in 2019 ferrying crews two and from the ISS, operating alongside Boeing’s CST-100 Starliner capsule. Initial flights of the Dragon 2 were intended to see the vehicle make a “traditional” parachute descent through Earth’s atmosphere followed by an ocean splashdown – the technique currently used by the uncrewed Dragon I ISS resupply vehicle.

However, SpaceX had planned to shift Dragon 2 landings from the sea to land – using parachutes for the majority of the descent back through the atmosphere, before cutting the vehicle free and using the built-in Super Draco engines (otherwise used as the crew escape system to blast the capsule free of a Falcon launch vehicle if the latter suffers any form of pre- or post-launch failure). The engines would fire during the last few metres of decent, placing the capsule into a hover before setting it down on four landing legs.

Extensively tested in tethered “hover” flights, propulsive landings would in theory made the recovery and refurbishment of Dragon capsules for future launches a lot easier, lowering the overall operating costs for the capsule. In announcing the decision to scrap the propulsive landing approach, Musk indicated it would have unnecessarily further drawn out the vehicle’s development as SpaceX sought to satisfy NASA’s requirements for crewed vehicle operations.

The decision also affects Musk’s hope of placing a robotic mission on the surface of Mars in 2020. Under that mission, a special cargo version of Dragon 2 – called Red Dragon- would fly a NASA science payload to Mars and use supersonic propulsive landing to slow itself through the tenuous Martian atmosphere and achieve a successful soft landing. This approach was seen as ideal, because using parachutes on Mars is extremely difficult with heavy payloads – NASAs studies suggest parachute on Mars have an upper limit of payloads around 1.5-2 tonnes. A Red Dragon capsule is liable to mass around 8-10 tonnes.

SpaceX have dropped plans to use propulsive landings on both their crewed Dragon 2 vehicles returning from the ISS and on their Red Dragon automated Mars lander (above). Credit: SpaceX

However, Musk no longer believes the use of a propulsive landing mechanism is “optimal” for Red Dragon, and the company has a better way of realising their goal – although he declined to indicate what this might be. Instead, propulsive landing systems would seem to be something the company will return to in the future – particularly given their hopes of placing vehicles massing as much as 100 tonnes on the surface of Mars.

No, ET Isn’t Calling Us

The Internet was agog recently after it was announced some very “peculiar signals” had been noticed coming from Ross 128, a red dwarf star just 11 light-years away. While not known to have any planets in orbit around it, and despite the best attempts of astronomers – including the team picking up the signals at the Arecibo radio telescope, Puerto Rico – news of the signals led to widespread speculation that “alien signals” had been picked up.

The usual signals – officially dubbed the “Weird!” signal, due to the comment made in highlighting the signals in an image – were first picked up on May 12th/13th, 2017. However, it was not until two weeks later that the signals were identified and analysed, the PHL team concluding that they were not “local” radio frequency interference, but were in fact odd signals coming from the direction of Ross 128 – sparking the claims of alien signals, even though the director at PHL and the survey team leader -Abel Mendez – was one of the first to pour water on the heat of the speculation. “In case you are wondering, he stated in response to the rumours, “the recurrent aliens hypothesis is at the bottom of many other better explanations.”

The Weird! signal. Credit: UPR Aricebo

Without drawing any conclusions on what might be behind the signals, PHL liaised with  astronomers from the Search for Extra-Terrestrial Intelligence (SETI) Institute to conduct a follow-up study of the star. This was performed on Sunday, July 16th, using SETI’s Allen Telescope Array and the National Radio Astronomy Observatory‘s (NRAO) Green Bank Telescope. The fact that SETI was involved probably also helped fan the flames of “alien signal” theories. However, initial analysis of the signal and the portion of the sky where it was observed have suggested a far more mundane explanation:  geostationary satellites.

“The best explanation is that the signals are transmissions from one or more geostationary satellites,”  Mendez stated in an announcement issued on July 21st. “This explains why the signals were within the satellite’s frequencies and only appeared and persisted in Ross 128; the star is close to the celestial equator, where many geostationary satellites are placed.”

While certain this explanation is correct, Mendez does note it doesn’t account for the strong dispersion-like features of the signals (diagonal lines in the figure). His theory for this is that it is possible multiple reflections caused the distortions, but the astronomers will need more time to evaluate this idea and other possibilities.

So sorry, no ETs calling out into the night – yet.

Space Sunday: anniversaries, storms and hidden worlds

July 16th, 1969. A Saturn V rocket lifted the crew of Apollo 11 – Neil A. Armstrong, Edwin Eugene “Buzz” Aldrin Jr and Michael Collins –  on their way to the Moon, and the first manned landing there. Credit: NASA

July is a celebratory month for the US space programme. I’ve already written about July 4th marking the 20th anniversary of America – and the world – having had a continuous robotic presence on or around Mars for 20 years. This week, July 16th and July 20th mark the anniversaries of perhaps the two most momentous days in human space flight – the Lift-off of the Apollo 11 mission to land men on the lunar surface and, on July 20th, the actual landing of the Lunar Excursion Module Eagle on the Sea of Tranquillity. Neil A. Armstrong and Edwin “Buzz” Aldrin  spent 21.5 hours there, while their colleague Michael Collins (the “forgotten third man” of Apollo 11) orbited the Moon aboard the Command and Service Module Columbia, carrying out a range of science work as he awaited his compatriots’ ascent back to orbit.

The Apollo programme, although ultimately dedicated to meeting John F. Kennedy’s 1961 goal of “putting a man on the Moon and returning him safely to the Earth”, actually had its roots in President Dwight D. Eisenhower’s administration, when it was seen as a logical progression from America’s single-seat Mercury programme to a vehicle capable of carrying a crew of three on a range of mission types, including ferrying crews to a space station, performing circumlunar flights, and eventually forming part of manned lunar landings.

Apollo was a bold venture, particularly when you consider Kennedy’s directive that America commit itself to achieving a manned landing on the Moon before the end of the 1960s, given in a stirring address before Congress on May 25, 1961 came just twenty days after NASA had finally managed to pump a man  – Alan Shephard – into space on a sub-orbital flight, while their first orbital success with John Glenn was still nine months in the future. It was a programme which was politically motivated to be sure, but which nevertheless yielded scientific and technological results which helped shape both our understanding of the solar system and helped improve ours lives on many levels. It raised the potential of human space exploration high in the public consciousness, and was illuminated by tremendous successes whilst also and shadowed by moments of tragedy and near-tragedy.

A sketch of the Apollo lunar landing mission profile produced as a part of NASA’s post Apollo 8 mission report of February 1969 annotating how the mission would be undertaken

As well as the missions themselves and the hardware required to carry them out – the Command and Service Module, the Lunar Excursion Module, the Saturn family of rockets (including the mighty Saturn V), Apollo perhaps did more than any over programme to shape NASA. It gave rise to the massive launch infrastructure at Merritt Island, Florida – now known as the Kennedy Space Centre – including the historic launch pads of Launch Complex 39, used by both Apollo and the shuttle, and now used by SpaceX and (soon) by NASA’s massive Space Launch System rockets; the Vehicle Assembly Building (then called the Vertical Assembly Building), where the Saturn rockets were assembled ready for launch, the still-used Launch Control Complex, and more. At the same time, Apollo gave NASA its operational heart for human space missions – the Manned Spaceflight Centre (now called the Johnston Spaceflight Centre) on land just outside Houston, Texas, donated to NASA by Rice University.

The entire history of the programme is a fascinating read – the politics, both in Washington (Kennedy’s own s science advisor, Jerome Wiesner, was quite vociferous in opposing the idea of sending men to the Moon) and in NASA (where a fierce difference of opinion was apparent in how the mission should be carried out. It’s a story I may some day plumb in a Space Sunday “special”, but for now I’ll simply say that all things considered, Apollo was a success, albeit one very self-contained. Six missions to the surface of the Moon, nine missions to and around the Moon, and the opportunity to increase our understanding of Earth’s natural satellite both by a human presence there and afterwards, thanks to the equipment left behind.

Armstrong, Collins and Aldrin pose for an official Apollo 11 crew shot, May 1st, 1969

New Horizons Pluto Flyby

July 14th marked the second anniversary of the New Horizons spacecraft’s flyby of Pluto and Charon – a high-speed dash between the two lasting mere hours, after a nine-and-a-half year flight simply to reach them. Brief though the encounter might have been, the spacecraft returned such a wealth of data and images that our view of Pluto and its companion has been forever changed, with Pluto in particular – as I’ve often referenced in these Space Sunday pieces –  revealing itself to be an enigma wrapped in a puzzle, determined to shatter our understanding of small planetary bodies in the solar system.

Such is the wealth of data gathered by the probe, coupled with the distances involved and the rate at which it could transmit data back to Earth, it took 16 months of all of the information stored aboard New Horizons to be returned to scientists here on Earth.

The July 14th mosaic of Pluto. The heart-shaped region is informally called “Tombaugh Regio” in honour of Pluto’s finder, Clyde Tombaugh. The left lobe of the “heart” is a vast icy plain. Credit: NASA/JHUAPL/SwRI.

To mark the second anniversary of New Horizons’ flyby, NASA released a new video using actual New Horizons data and digital elevation models of Pluto and Charon, to offer a unique flight across Pluto.

The movie starts over the highlands to the south-west of “Sputnik Planum’s” great nitrogen ice sheet (visible to the right as the movie progresses), with the track of the film passing directly over the chaotic cratered and mountain terrain of “Cthulhu Macula”. moving northwards, the flight passes over the fractured highlands of “Voyager Terra” then back southwards over Pioneer Terra, distinguished by pitting, before concluding over the bladed terrain of Tartarus Dorsa in the far east of the encounter hemisphere.

Continue reading “Space Sunday: anniversaries, storms and hidden worlds”