Space Sunday: of tweets, space stations and helicopters

NASA has linked the Moon with Mars for decades, but only really emphasised the former whilst only talking vaguely about the latter. This lunar “bias” might have been the reason for a confusing tweet by President Trump on June 7th, 2019. Credit: NASA

In December 2017, President Trump signed Space Policy Directive (SPD)-1, directing NASA to focus on returning human to the Moon. More recently this has seen the White House to direct NASA to achieve this return by 2024, and not 2028, the US space agency’s target year. We’ve also seen the programme gain a name – Project Artemis (Artemis being the sister of Apollo in Greek mythology) and the White House and Congress getting into something of a tussle over NASA’s 2020 budget: the former wants to add US $1.6 billion to NASA’s budget specifically for the lunar effort, the latter wants to give NASA an extra US $1.3 billion for programmes other than a return to the Moon.

However, tussles over budget increases aside (and even if it were granted, US $1.6 billion is merely a splash of the level of financing NASA realistically needs to reach the Moon by 2024), the US space agency has at least had a goal to aim for, until President Trump appeared to rock the boat on June 7th, when he issued a tweet that appeared to suggest NASA shouldn’t be aiming for a return to the Moon, but should be focused on Mars.

Donald Trump’s June 7th tweet concerning NASA’s human space flight goals

The tweet drew a huge amount of backlash from people trying to claim that Trump regards the Moon as “part of Mars”. However, those doing so are somewhat misguided. Anyone with any understanding of NASA’s plans / desires over the last 30 years with regards to Mars know that the Moon has been indelibly linked to that effort; it’s been pretty much the view that the one (Mars) cannot be achieved without the other (a return to the Moon).

The cornerstone of this claim has always been that the Moon can be used as a testing ground for technologies that might assist us in the exploration / settlement of Mars.

The Moon provides an opportunity to test new tools, instruments and equipment that could be used on Mars, including human habitats, life support systems.

– NASA website

But how accurate is this assertion? “Not very” is a not unfair summation. Mars is a very different destination to the Moon. Just landing there requires substantially different capabilities to those required for landing on the Moon.

For example, Mars has an atmosphere and the Moon does not. This can be both an advantage (it can be used to help slow an incoming vehicle down on its way to the surface) and a disadvantage (lander vehicles must be capable of withstanding entry into that atmosphere and making use of it during descent, which adds significant complexity to them). Similarly, the technology needed to get off of Mars is different: more powerful motors are required to counter the greater gravity (twice that of the Moon), these in turn require more fuel, which makes the ascent vehicle more complex – which could also feed back into the decent vehicle as well, if a paired system, such as proposed for use with the Moon, is to be used.

That Mars has an atmosphere means that very different technical approaches must be taken for landing there compared to landing on the Moon. Credit: The Mars Society

Similarly, how local resources on the Moon and Mars might be used differ substantially. With the Moon, it is proposed water ice in the southern polar regions is leveraged as a means of producing oxygen, water and fuel stocks. This could also be done on Mars – but there is a far more accessible resource on Mars for this: its carbon-dioxide rich atmosphere.

Using a 19th century technique called the Sabatier Reaction, water, oxygen and methane can literally be produced out of the Martian air. The oxygen and methane can be used a fuel stocks, while the air and water have obvious life-support options.

The Sabatier reaction: (1) hydrogen feedstock carried to Mars is combined with the carbon-dioxide atmosphere to produce methane (CH4), used as propellant, and water (H2O). (2) Te water is split into hydrogen, which is fed back to to help support the first reaction, and oxygen, also used as a propellant. (3) A related reaction takes the CO2 atmosphere and splits it into “waste” carbon, returned to the atmosphere and oxygen, which can be used as propellant or to supplement air supplies.

Tests carried out by the Mars Society – and verified in a 2003 joint NASA / ESA study – show that an automated lander vehicle carrying just 6 tonnes of hydrogen to the surface of Mars could produce 112 tonnes of methane / oxygen fuel by the time a human crew arrives 18 months later – enough to power their ascent vehicle back to Mars orbit or – depending on the mission architecture used – even all the way back to Earth orbit.

And when it comes to things like life support systems and radiation shielding – do we actually need the Moon to test these for an eventual Mars mission? Actually no. In terms of life support systems, we already have the infrastructure in place for testing them, just 400km from the surface of Earth; we call it the International Space Station. And when it comes to testing technologies to protect against radiation – even GCRs (galactic cosmic rays) – this can be done through other, and potentially less costly, means.

Which is not to say that we shouldn’t be going to the Moon; the potential science returns are as significant as those in going to Mars. However, it’s not unfair to say that for the last 30 years, the constant linking of the Moon and Mars has resulted in NASA being unable to achieve either.

Thus, Trump’s tweet shouldn’t be seen as any kind of belief on his part that the Moon is anyway “a part” of Mars, but rather a reflection (or possibly parroting) of the frustration some space advocates feel in the way NASA constantly links the two, with the emphasis perhaps too closely focused on the Moon, rather than looking at the potential and inspiration humans face in going to Mars.

However, where Trump’s tweet is potentially harmful is in the confusion it might cause. Trump’s spur-of-the-moment tweets have an unfortunate habit of becoming “policy”. As such, it was hard to know if the June 7th tweet was simply parroting something heard, or whether it was signalling a genuine change in direction for US space policy. As such, some, such as the Planetary Society, more correctly sought not to belittle the Moon “a part” of Mars element of Trump’s tweet, but to request a clarification of anticipated goals.

The Planetary Society’s response to Trump’s Tweet, highlighting the real concerns, not “he doesn’t know the Moon from Mars” nonsense

This clarification appeared to come at the National Space Society’s International Space Development Conference in Washington DC on June 8th. At that event, Scott Pace, Executive Secretary of the National Space Council, indirectly referenced Trump’s tweet, stating that while efforts to return humans to the lunar surface by 2024 were ongoing, NASA and the administration should devote more attention to long-term aspirations of human Mars missions.

The president’s comments was a criticism not of going back to the moon but rather not paying more attention to that long-term goal.  We’re head down, working on the immediate execution of this [and] I don’t think we always do a good job speaking to the larger vision that this is part of. What he [Trump] is doing is stepping back and expressing, I think, a very understandable impatience with how long all of that takes, and sometimes we miss the bigger picture.

– Scott Pace, Executive Secretary, the National Space Council

Continue reading “Space Sunday: of tweets, space stations and helicopters”


Space Sunday: ExoMars, a magic movie and a “forbidden planet”

A model of the ExoMars rover, Rosalind Franklin, in the ROCC Mars Yard. Credit: ESA

When it comes to Mars rover missions, eyes tend to be firmly on NASA’s Mars Science Laboratory Curiosity vehicle and the upcoming Mars 2020 rover.

However, if all goes according to plan, come 2021, Curosity and Mars 2020 will have a smaller European cousin trundling around Mars with them, thanks to the arrival of ExoMars rover Rosalind Franklin. While the rover isn’t due to be launched for just over 12 months, the European Space Agency (ESA) take two further steps towards the mission in June 2019.

At the start of the month, ESA inaugurated the Rover Operations Control Centre (ROCC) in Turin, Italy. Designed to be the hub that orchestrates all operational elements supporting Rosalind Franklin once it has been delivered to the surface of Mars by its Russian-built landing platform, ROCC is one of the most advanced mission operations centres in the world.

This is the crucial place on Earth from where we will listen to the rover’s instruments, see what she sees and send commands to direct the search for evidence of life on and under the surface.

– Jan Wörner, ESA’s Director General

As well as providing communications with the rover, data processing, and science and engineering support, the ROCC boasts one of the largest “Mars Yard” sandboxes currently available. Filled with 140 tonnes of Martian analogue soil, it offer a range of simulated terrains similar to those the rover might encounter within its proposed landing site. Such simulation capabilities will allow Earth-based teams to carry out a wide range of activities  using the rover’s Earth-bound twin before committing to particular courses of action, or to help assist the rover should it get into difficulties on Mars.

Use of such environments is not new; NASA uses an assortment of indoor and outdoor Mars Yards to help support their static and rover surface operations on Mars. However, the ROCC Mars Yard is somewhat unique in its capabilities.

For example, as ExoMars has a drilling system designed to reach up to 2 metres (6 ft) below the Martian surface, the ROCC Mars Yard includes a “well” that allows rover operators to exercise the full sequence of collecting Martian samples from well below the Martian surface. This well can be filled with different types / densities of material, so if the Rosalind Franklin gets into difficulties in operating its drill, engineers can attempt to replicate the exact conditions and work out how best to resolve problems.

The “well” in the ROCC Mars Yard, as seen from underneath, allowing the ExoMars rover mission team rehearse the full range of sample gathering operations. Credit: ESA

And while it is not part of the main Mars Yard, ROCC rover operations will be assisted by a second simulation centre in Zurich, Switzerland. This 64-metre square platform can be filled with 20 tonnes of simulated Martian surface materials and inclined up to 30-degrees. Engineers can then use another rover analogue to see how the rover might – or might not – be able to negotiate slopes.

For example, what might happen if the Rosalind Franklin tries to ascend / descend a slope covered in loose material? What are the risks of soil slippage that might result in a loss of the rover’s ability to steer itself? What are the risks of the surface material shifting sufficiently enough that the rover might topple over? What’s the best way to tackle the incline? The test rig in Zurich is intended to answer questions like these ahead of committing the Mars rover to a course of action. In fact, it has already played a crucial role in helping to develop the rover’s unique wheels.

Both the Mars Yard and the Zurich facility will be used throughout the rover’s surface mission on Mars, right from the initial deployment of the rover from its Russian landing platform (called Kazachok, meaning “little Cossack”).

With the Mars yard next to mission control, operators can gain experience working with autonomous navigation and see the whole picture when it comes to operating a rover on Mars. Besides training and operations, this fit-for-purpose centre is ideal for trouble shooting.

– Luc Joudrier, ExoMars Rover Operations Manager

The Mars Yard can also simulate the normal daytime lighting conditions on Mars. Credit: ESA

June will see the new centre commence a series of full-scale simulations designed to help staff familiarise themselves the centre’s capabilities before commencing full-scale rehearsals for  the rover’s arrival on Mars in March 2021.

Meanwhile, in the UK – which carries responsibility for assembling the rover – Rosalind Franklin is coming together. The drill and a key set of scientific instruments—the Analytical Laboratory Drawer—have both been declared fit for Mars and integrated into the rover’s body. Next up is the rover’s eyes – the panoramic camera systems. Once integration in the UK has been completed, the rover will be transported to Toulouse, France, where it will be put through a range of tests to simulate its time in space en route to Mars and the conditions its systems will be exposed to on the surface of Mars.

The targeted landing site for Rosalind Franklin is Oxia Planum, a region that preserves a rich record of geological history from the planet’s wetter past. With an elevation more than 3000 m below the Martian mean, it contains one of the largest exposures of clay-bearing rocks that are around 3.9 billion years old. The site sits in an area of valley systems with the exposed rocks exhibiting different compositions, indicating a variety of deposition and wetting environments, marking it as an ideal candidate for the rover to achieve its mission goals.

Continue reading “Space Sunday: ExoMars, a magic movie and a “forbidden planet””

Space Sunday: Venus, Pluto, and a mini round-up

This cylindrical map of Venus reveals the planet’s hostile surface beneath the clouds, a place of volcanoes and vast volcanic plains with few impact craters. The latter demonstrates both how volcanism has played a roll in “smoothing over” the surface of Venus in the past, and how effectively the dense atmosphere acts as a shield in burning-up incoming space debris. Credit: NASA

Once regarded as a planet that may harbour life, Venus – as we know it today – is a hellish place. Cursed with a runaway greenhouse effect, the surface temperatures (averaging 735 Kelvin or 462°C / 863°F) are hot enough to melt lead and mark it was the hottest planetary body in the solar system. The atmosphere is both a toxic cauldron so dense that it exerts a surface pressure 92 times greater than our own – the equivalent of being 900 m (3,000 ft) under water on Earth.

Venus is also unusual in other ways: it has a retrograde rotation (it spins on its axis in the opposite direction to Earth and most of the other planets), and it takes 243 terrestrial days to complete one rotation but only takes 224.7 days to complete an orbit of the Sun, making a “day” on Venus longer than a year.

Despite its hostile conditions, it has long been believed that Venus was at one time in its ancient past a far more hospitable world, potentially warm a wet, and spinning a lot faster on its axis (quite possibly in the same direction as the Earth spins). However, at some point  – so the accepted theories go – Venus experienced a massive impact, one sufficient enough to slow – and even reverse – its rotation and which also left it the broiling, hostile world we know today.

An artist’s impression of how Venus might have appeared some 2.5 – 3 billion years ago, at a time when a globe-spanning ocean might have started to affect the planet’s rotation, slowing it and eventually giving rise to the planet’s runaway greenhouse effect. Credit: NASA

However, a new study involving the University of Bangor, Wales, the University of Washington and NASA, suggests not only did Venus once had a liquid water ocean, but that ocean may have actually been the catalyst that brought about the planet’s dramatic change.

To put it simply, tides act as a brake on a planet’s rotation because of the friction generated between tidal currents and the sea floor. On Earth, this results in the length of a day being shortened by about 20 seconds every million years. Given this. the team responsible for the  study investigated how such interactions might impact Venus. Using a numerical tidal model, the accepted belief that Venus once had a world-girdling ocean, and applying it to planetary rotational periods ranging from 243 to 64 sidereal Earth days, they calculated the tidal dissipation rates and associated tidal torque that would result from each variation in ocean depth and rotational period. Their work revealed that ocean tides on Venus would likely have been enough to slow the planet’s rotation it down by up to 72 terrestrial days every million years.

This might not sound a lot, but of the course of around 10-50 million years, it would have been enough to slow Venus’s rotation and bring it to how we see it today. In turn, this slowing of rotation would have accelerated the evaporation of an ocean waters on the sunward facing side of the planet, both increasing the atmospheric density and trapping more heat within the atmosphere, accelerating the planet’s greenhouse effect, in turn increasing the rate of ocean evaporation in what would have been a closed cycle. Add to that the planet’s known volcanism, and the team estimate that it would have taken around 100-120 million years to turn Venus into the planet we see today.

This work shows how important tides can be to remodel the rotation of a planet, even if that ocean only exists for a few 100 million years, and how key the tides are for making a planet habitable.

– study co-lead Dr. Mattias Green, University of Bangor

The study findings have potentially important implications for the study of extra solar planets, where many “Venus-like” worlds have already been found. From this work, astronomers have a model that could be applied to exoplanets located near the inner edge of their circumstellar habitable zones, helping to determine whether they might have at some point potentially have had liquid water oceans, and how those oceans may have affected their development.

Fly Your Name to Mars

Mid July through August 2020 will see NASA’s next rover mission launched to Mars, and as with a lot of their recent exploratory missions, NASA is giving members of the public the opportunity to have their names flown with the vehicle.

Between now and September 30th, 2019, NASA is inviting one million members of the public to submit their names and postal codes to Send Your Name (Mars 2020). These names will then be laser-etched onto a little chip roughly the size of a penny that will be mounted on the rover and carried to Mars. In return, successful applicants obtain a “boarding pass” similar to the one shown below, indicating their name will be flown on the mission.

My Mars 2020 boarding pass

The Mars 2020 rover is based on the same chassis and power system as used by the Mars Science Laboratory Curiosity rover. It will also use the same type of landing system, featuring a rocket-powered “skycrane” that will hover a few metres above the surface of Mars and then winch the rover down to the surface. However – and for the first time in the history of planetary exploration – Mars 2020 will have the ability to accurately re-target its landing point prior to committing to lower the rover, thus allowing it to avoid last-minute obstructions that might otherwise damage the rover or put it at risk.

Core to this capability is a instrument called the Lander Vision System (LVS), which has been undergoing tests in California’s Death Valley attached to a helicopter. LVS is designed to gather data on the terrain the lander is descending towards, analyse it to identify potential hazards and then feed the information to a guidance system called Terrain-Relative Navigation (TRN), which can then steer the landing system away from hazards, allowing the skycrane to winch the rover to the ground in a (hopefully) a safe location.

The Mars 2020 rover’s LVS under test in Death Valley, California, mounted on the front of a helicopter. Credit: NASA/JPL

Mars 2020 is due to be launched between July 17th and August 5th 2020 to arrive on Mars at Jezero Crater on February 18th, 2021.

Continue reading “Space Sunday: Venus, Pluto, and a mini round-up”

Space Sunday: Moon talk

An artist’s impression of an unpiloted commercial lander leaving a scaled-back LOP-G for a descent to the surface of the Moon ahead of a 2024 human return to the lunar surface.Credit: NASA

On May 13th, 2019, NASA announced that the Trump Administration had requested a US $1.6 billion bump to the space agency’s 2020 budget, to assist it in its efforts to return humans to the Moon by 2024. If approved, the increase will be used by NASA as a “down payment” – or more correctly seed money – that will in particular be put towards studies and projects related to the development of a human-rated lunar lander.

Given just how much needs to be done, US $1.6 billion really isn’t that much; in 2019, NASA was allocated US $4.5 billion of a US $19.2 billion to put towards its lunar efforts, most of which was used in the development of the initial Space Launch System (SLS) rocket and the ongoing work in developing the Orion Multi-Purpose Crew Capsule, with small amounts being allocated to studies such as the Lunar Orbital Platform-Gateway (LOP-G) station, and development of a new generation of lunar-capable space suits.

But these capabilities are just a part of the infrastructure NASA needs to build if it really is to achieve a human return to the Moon by 2024. This includes the LOP-G itself, the need to carry out more extensive robotic exploration of the lunar south pole, the selected location for the landing, the development, testing and deployment of these robot missions, the development of the technologies NASA have touted as being required for a long-term human presence on the Moon (not all of which will be required in the initial phases of the return, admittedly). And, of course, there is the need to develop and test the lunar lander itself.

The Lockheed Martin Orion MPCV Ground Test Article (GTA), a version of the vehicle constructed specifically for testing under simulated conditions to demonstrate the environmental integrity and operational capability of the craft. Credit: NASA / Lockheed Martin

The announcement was used by NASA to springboard a series of new PR videos to help promote their lunar aspirations, including one narrated by William “James T. Kirk” Shatner – are upbeat whilst being light on details. Even so they are useful watching for those wanting to have the agency’s aims painted in the broadest of brush strokes.

Part of this PR drive included the confirmation of the lunar programme’s official title: Artemis. The daughter of Zeus and Leto, Artemis was the Greek goddess of the hunt, the wilderness, wild animals, and chastity, the patron and protector of young girls, and was worshipped as one of the primary goddesses of childbirth and midwifery.

However, in this instance, the most important aspect of Artemis’ legend is that she was regarded as the goddess of the Moon – and the twin sister to Apollo. As such, the name is clearly intended as a way to indirectly echo the can do attitude that marked the Apollo era.

NASA’s plans to send humans to the Moon by 2028 had three parts that could be launched, in part, by commercial rockets, and which used a fully operational LOP-G. If the White House target date of 2024 is to be met, these plans must be vastly accelerated – and NASA budget will require a committed year-on-year increase from the US government. Credit: NASA

With one billion of the additional budget request being specifically for use in lunar lander development, on May 17th, NASA confirmed that it has selected 11 companies to begin studies and initial prototype development of portions of human landers intended for use in the 2024 (and beyond) missions.

Some US $45.5 million has been set aside by NASA in support of all 11 companies, each of which is expected to make its own contribution  – up to 20% of the total cost of their study / prototype programme to the development work. The awards are part of NASA’s Next Space Technologies for Exploration Partnerships (NextSTEP) programme, a series of broad agency announcements that support public-private partnerships to develop technologies needed for NASA’s exploration plans.

The 11 companies selected comprise Aerojet Rocketdyne, Blue Origin, Boeing, Dynetics, Lockheed Martin, Masten Space Systems, Maxar Technologies, Northrop Grumman Innovation Systems, OrbitBeyond, Sierra Nevada Corporation and SpaceX.

Given Lockheed Martin have been working on their own proposals for a lunar lander for some time (see Space Sunday: Moon, Mars, and abort systems), and Blue Origin recently unveiled their own lander, Blue Moon (see Space Sunday: a Blue Moon, water worlds and moving house), their inclusion in the list is unsurprising. Neither is the inclusion of the likes of SpaceX, Boeing, Sierra Nevada Corporation and Northrop Grumman. What is perhaps surprising is the inclusion of start-ups like OrbitBeyond (founded in 2018), which was initially granted a Commercial Lunar Payload Services (CLPS) contract by NASA, allowing it to bid on delivering science and technology payloads to the Moon, rather than being involved in the development of human-rated lander vehicles.

Blue Origin, who recently revealed a full-scale model of their Blue Moon lunar lander, are one of 11 companies selected by NASA to carry out initial work into a human-rated Moon lander. Credit: Blue Origin

The awards require companies to pay at least 20 percent of the overall cost of each study or prototype project, with the work to be completed in six months. To allow the companies to start work immediately, the participating companies are allowed to start work while the contract terms are still being negotiated.

However, it’s not all good news. The 2020 federal budget has yet to be passed by Congress, and on May 16th, the House Appropriations Committee released an updated 2020 federal budget proposal of their own. This includes an additional US $1.3 billion in spending for NASA – but almost none of it is earmarked for NASA’s exploration programmes, which encompass a return to the Moon. Instead, under the House proposal, that programme is effectively cut by US $618 million.

Continue reading “Space Sunday: Moon talk”

Space Sunday: a Blue Moon, water worlds and moving house

Jeff Bezos, the Blue Origin founder, unveils a full-scale model of the company’s Blue Moon lunar lander. Credit: Jeff Foust

On May 9th 2019, and after a lot of speculation following an April tweet (see Space Sunday: asteroid impacts and private space flights), Blue Origin founder Jeff Bezos unveiled the next step in the company’s space aspirations: their Blue Moon lunar lander.

The vehicle has been in development for some three years, with precious few details being given until now, other than it was initially indicated it would be capable of delivering up to 4.5 tonnes of equipment and material to the Moon’s surface in support of human missions. However, the vehicle has apparently been through a number of design cycles, and the unveiling presented a massively capable machine which  – while it wasn’t openly stated at the May 9th event (but is indicated on the Blue Origin website) – could be used in support of NASA’s drive to return humans to the surface of the Moon by 2024.

Somewhat resembling the descent stage of the Apollo Lunar Excursion Module (LEM), Blue Moon has the capability to complete variable missions up to and including landing crews on the Moon’s surface and lifting them off again. In its “basic” form, the lander will be able to land 3.6 tonnes of cargo on the Moon, while a “stretch tank” version will be able to increase that deliverable payload to 6.5 tonnes.

The Blue Moon Lander with a set of four remote landers on its deck, and showing the “bonus payload” bay above the smaller of the distinctive spherical fuel tanks, which will contain liquid oxygen (LOX). Credit: Blue Origin

This payload will be carried on the flat upper deck of the lander, which will also include a robot crane (or cranes) capable of lifting it down to the Moon’s surface. In addition, the lander has an internal payload bay designed to deliver small satellites into lunar orbit as a “bonus mission”.

The most interesting element of the vehicle is perhaps its propulsion / power system. Blue Moon will be powered by the company’s new BE-7 motor, which uses liquid hydrogen and liquid oxygen propellants rather than storable hypergolic fuels. This allows the motor to generate up to 10,000 lbs of thrust, whilst also being “deeply throttlable”. The initial version of the motor will undergo its first “hot fire” test in the summer of 2019.

While the offer better performance capabilities than hypergolic fuels, liquid propellants need to be held at low temperatures, otherwise they can start to “boil off” to a gaseous state if they start to get “warm” (this is why liquid fuelled rockets appear to “steam” on the launch pad: they are venting fuel that has turned to gas that needs to be released to avoid over-pressurising and rupturing tanks).

While Blue Origin believe the exceptional low temperatures of the 2-week lunar night will help keep the lander’s fuel stocks cold and liquid, Blue Moon will still need refrigeration / insulation to prevent undue boil-off of the propellant stocks, which will add some weight to the vehicle. However, Blue Origin sees some boil-off of the liquid hydrogen ad advantageous: they plan to use boiled-off gaseous liquid hydrogen to help keep the liquid oxygen cold in its tanks and also as feedstock for the power cells that will be used to provide electrical power to the vehicle.

Bezos demonstrates Blue Moon’s ability to deliver a rover vehicle (mock-up) to the lunar surface during the May 9th event. Credit: Blue Origin

The latter are important again because of that 2-week lunar night. when there will be no sunlight to provide energy to any solar cells the vehicle might otherwise be equipped with to provide electrical power.

While initially intended to deliver science missions and payloads to the surface of the Moon in readiness for human landings. However, a future development with the vehicle could see it fitted with an upper stage crew / ascent module. Whether or not this might be used as part of NASA’s ambitions to met the goal of returning humans to the Moon by 2024 remains to be seen. However, Bezos has indicated Blur Origin is willing to help NASA to achieve this goal, and pointedly notes that that the company has a three-year headset in developing their lander when compared to others.

An artist’s impression of the Blue Moon crewed lander with the crew / ascent module on top. Credit: Blue Moon

However, even outside of NASA’s plans, Blue Origin has its own hopes to send humans to the Moon. As I noted in my last Space Sunday report, the company’s April tweet about this announcement made an indirect reference to Shackleton Crater close to the Moon’s south pole. This is one of a number of craters believed to have water ice deposits within it, making it an ideal location for establishing a lunar base – and Blue Origin and Bezos have previously indicated it is their target for establishing a lunar base.

Lunar water ice is also another reason for the company opting to use liquid propellants with Blue Moon. Should their aspirations with Shackleton come to pass, then water ice – hydrogen and oxygen  – becomes a feedstock for refuelling Blue Moon landers once they are on the Moon, making them more efficiently reusable.

Blue Moon will be 7 metres (23 ft) across its payload platform, which will stand some 4m (14 ft) above the lunar surface on the basic lander. Fully loaded and fuelled, Blue Moon will weigh 15 tonnes at launch, but having burned the majority of its fuel during its flight and landing, will weigh only 3 tonnes after landing. By comparison, the Apollo LEM weighed 16.4 tonnes fully fuelled and stood 7.07 m tall, including the crewed ascent stage. Meanwhile, Lockheed Martin’s proposed lunar lander could be as much as 62 tonnes fully fuelled and stand 14 m (46 ft) tall.

Bezos declined to answer specifics on the vehicle such as when test flights are likely to commence, what will be the launch vehicle (although Blue Origin’s New Glenn would appear to be the most obvious choice), or how much overall development of the lander and its variants will cost. Doubtless, some of these details will become public in time.

Continue reading “Space Sunday: a Blue Moon, water worlds and moving house”

Space Sunday: asteroid impacts and private space flights

An artist’s impression of a small (approx 60m) asteroid air burst disintegration over a city. Credit: Igor Zh./Shutterstock

I’ve written about the risk posed by the potential impact of a Near Earth Object on this planet several times within these Space Sunday articles. While they are rare, as we’ve seen with the Tunguska event of 1908, and the more recent  2013 Chelyabinsk air-blast and 2018 LA (ZLAF9B2) in June 2018, objects of a size sufficient enough to survive their initial entry into the Earth’s atmosphere before being ripped apart in a violent explosion can and do exist.

Nor is Earth alone in the threat – as witnessed by those observing the lunar eclipse of January 21st, 2019, the Moon can be hit as well. At 04:41 GMT, during the period of totality during that eclipse, numerous astronomers in North and South America and in Western Europe saw a sudden bright flash lasted less than 1/3 of a second. It was later attributed to an object around 30 to 60 centimetres (1 to 2 ft) across striking the Moon at around 61,000 km/h, producing a new crater somewhere between 10 and 15 metres (32 to 49 ft) across.

While the majority of the 10+ million objects thus far found crossing Earth’s orbit as they go around the Sun pose no real threat to us (in fact, the number of Potentially Hazardous Asteroids, or PHAs, has been put at just 2,000), and the risk of a substantial impact occurring in anyone’s individual lifetime is relatively remote, the fact is that – as Douglas Adams famously noted – space is big really big. Even the solar system is a vast place when compared to the size of Earth, big enough to hide any number of objects that might one day pose a very real threat to all life on Earth or, given humanity’s global distribution the potential to place one of our major cities at risk.

So how might we deal with such an eventuality? Currently, there are really only three practical options available to us – although others have been suggested, and more might be developed in the future. Which of them might be used depends on how much lead time we have in which to take action. To summarise:

  • The gravity tug: if the impact is decades away, a spacecraft with a motor such as an electric ion drive could rendezvous with the asteroid and enter a halo orbit around it. The motor could then be fired along the axis of flight, allowing the gravitational influence of the vehicle to “pull” the asteroid onto a new course. However, this option can really only be used if the inclination of the threatening asteroid is relatively close to that of Earth’s; if the two are very disparate, the time needed to get the spacecraft to the asteroid using gravity assist manoeuvres around the Earth or Venus or even Jupiter, might simply be too long.
The gravity tug explained. Credit: G. Manley / I. Pey
  • The Kinetic intercept: this uses brute force to deflect the asteroid by slamming relatively solid masses into to, their momentum serving to shunt it into a slightly altered orbit around the Sun that is sufficient for it to miss the Earth.
  • Nuclear deflection: similar to the kinetic intercept, but uses the shock waves of nuclear weapons detonated close to the asteroid to again shunt it into an altered orbit so it misses the Earth.

The major problem with the last two is the risk that if the asteroid is too fragile, rather than shunting it aside, they could shatter it, leaving Earth facing not s single object, but a scatter gun of debris, potentially with multiple elements large enough to devastate large areas of the planet’s surface should they enter the atmosphere and explosively disintegrate. This is also the reason why trying to directly blow an asteroid part using a nuclear strike isn’t regarded too favourably. There are other issues with each of these options that could also limit their effectiveness, or raise the need to repeat them, but they provide a general idea of how we might react.

NASA’s planned 2022 DART mission will deliberately smash a vehicle into a small asteroid to test the kinetic impact theory of asteroid deflection. Credit: NASA GSFC

Hence why the International Academy of Astronautics holds a Planetary Defence Conference every two years to discuss the latest findings with NEO and PHAs, and the ways and means to prevent such an impact – or at least the loss of life minimised. Since 2013, the 5-day conference has included a special “war game” type simulation to examine how a threat might be dealt with, and at the 2019 conference, held between April 29th and May 3rd, the simulation with publicly disseminated via social media as it progressed, to encourage grater public understanding about the need to better locate and track NEOs and PHAs (which are currently being discovered at the rate of around 700 a year).

In this simulation, which compressed an 8-year time frame into 5 days, the 200 astronomers, engineers, scientists and politicians at the conference were informed a large (fictional) asteroid around 300 metres across would slam into Colorado in 2027, unless then managed to divert it. Initially, things went well: a joint mission involving the USA, Russia, Europe, China and Japan used kinetic impacts to safely divert the bulk of the asteroid away from Earth. However, a 60m fragment broke away on a course that would see it hit the Earth’s atmosphere at 69,000 km/h (43,000 mph) and explode 15 km (9.3 mi) above Central Park, New York City. The force f the air blast would be sufficient to complete raze Manhattan and parts of New York City for a radius of 15 km (9.4 mi),  with the  effects of the blast felt up to 68 km (42.5 mi) from the epicentre. Plans were drawn up to try to deflect this fragment using a nuclear blast, but these became mired in political wrangling (not for the first time in these simulations)  until it was too late to achieve the desire deflection.

While such exercises might sound like scientists playing games, they do serve a purpose in that they help to underline the massive threat we face if we discover an asteroid is on a collision course with Earth – and the need for us to have better means to detect objects that might pose a threat early enough that we can take action, and also to better understand the processes – technical, scientific and political – that need to followed / overcome in order to prevent a collision.

They also highlight other issues as well. In this case, just how do you handle evacuating a city of 8 million souls? How much time is required (in the simulation, it came down to just 2 months)? What are the logistics required to ensure a (relatively) smooth evacuation? How and when should you tell the public? How do you avoid mass panic? This type of discussion is actually of major import, given current thinking is that if an object due to strike the Earth is 60 metres or less across, the focus should be on evacuating the area directly affected, rather than on trying to deflect it.

Continue reading “Space Sunday: asteroid impacts and private space flights”