Tag: Spaceflight

Space Sunday: rockets, exoplanets landers and asteroids

Posted on by Inara Pey
Fire in the hole! the Falcon Heavy’s 27 Merlin engines are test-fired on Pad 39A at NASA’s Kennedy Space Centre, January 24th, 2018. Credit: SpaceX

SpaceX faces a busy couple of weeks for the end of January and the start of February 2018. On Tuesday, January 30th, the company is set to launch Luxembourg’s SES-16/GovSat 1 mission on a Falcon 9 rocket from Launch Complex 40 at Canaveral Air Force Station on Florida’s coast. As is frequently the case with SpaceX missions, an attempt will be made to return the booster’s first stage to a safe landing  – this time at sea, aboard the Autonomous Spaceport Drone Ship Of Course I Still Love You in the Atlantic Ocean.

Then, if all goes according to plan, on Tuesday, February 6th, SpaceX will conduct the first launch of the Falcon Heavy booster which should be a spectacular event. As I’ve previously noted in these updates, Falcon Heavy is set – for a time at least – to be the world’s most powerful launch vehicle by a factor of around 2, and capable of lifting up to 54 tonnes to low Earth orbit, and of sending payloads to the Moon or Mars. The core of the rocket comprises three Falcon 9 first stages strapped side-by-side, two of which have previously flown missions.

For its first flight, the Falcon Heavy is set to send an unusual payload into space: a Tesla Roadster owned by Tesla and SpaceX CEO Elon Musk. It’s part of a tradition with SpaceX: mark a maiden flight with an unusual payload; the first launch of a Dragon capsule, for example, featured a giant wheel of cheese. If all goes according to plan, SpaceX hope to recover all three of the core stages by flying them back for touch downs; two of them on land, and one at sea using an Autonomous Spaceport Drone Ship.

The Falcon Heavy is raised to a vertical position on December 28th, 2017 in a launch pad “fit test”. Credit: SpaceX

As part of the preparations for any Falcon launch, SpaceX conduct a static fire test of the rocket’s main engines.For the Falcon Heavy, this took place on January 27th, 2018. These tests have come in for criticism from some quarters as a high-rick operation. However, to date, SpaceX has not suffered a single loss as part of such a test, although in September 2016, a Falcon 9 and its payload were lost while the vehicle was being fuelled in preparation for such a test. For the Falcon 9, the test involves firing the 9 Merlin main engines for between 3 and 7 seconds; with the Falcon Heavy test, and possibly to obtain additional vibration and stress data ahead of the launch, all 27 engines were fired for a total of 12 seconds – almost twice as long as the longest test of a Falcon 9.

Assuming the launch is successful, it will pave the wave for Falcon Heavy being declared operational. The second launch will most likely carried a Saudi Arabian communications satellite into orbit, and the third flight of the Heavy undertake the launch of multiple satellites. All three launches will be watched closely by the US Air Force, who are considering using the Falcon Heavy as a potential launch vehicle alongside the Falcon 9, which was added to the military launch manifest in 2016.

TRAPPIST-1: Further Look At Habitability

Since the confirmation of its discovery in February 2017 (read more here), the 7-exoplanet system of TRAPPIST-1 one has been the subject of much debate as to whether or not anyone of the planets might be habitable – as in, have suitable conditions in which life might arise.

As I’ve previously reported, while some of the seven planets sit within their parent star’s habitable zone where liquid water might exist, there are some negative aspects to any of the Earth-sized worlds harbouring life or having the right conditions for life. In particular, their parent star is a super cool red dwarf with all internal action entirely convective in nature. Such stars tend to have violent outbursts, so all seven planets are likely subject to sufficient irradiation in the X-ray and extreme ultraviolet wavelengths to significantly alter their atmospheres and rendering them unsuitable for life. Further, all seven are tidally locked, meaning they always keep the same face towards their parent star. This will inevitably give rise to extreme conditions, with one side of each world bathed in perpetual daylight and the other in perpetual, freezing darkness, resulting in atmospheric convection currents moving air and weather systems / storms between the two.

Artist’s concept showing what each of the TRAPPIST-1 planets may look like. A new study suggests TRAPPIST-1d and 1e might be the most potentially habitable. Credit: NASA

However, on the positive side, TRAPPIST-1 is sufficiently small and cool that, despite their proximity to it, the sunward faces of the planets won’t be as super-heated as might otherwise be the case. This also means that the extremes of temperature between the lit and dark sides of the planets aren’t so broad, reducing the severity of any storms some of them might experience. Now a team of researchers have identified the more likely planets within the seven which might have conditions conducive for life.

This involved certain assumptions being made, such as all the planets being composed of water ice, rock, and iron, and – given some of the data concerning the planets, such as their radii and masses, are not well-known – a range of computer models having to be built.

In putting everything together, the team concluded that TRAPPIST -1d and TRAPPIST-1e might prove to be the most habitable, with TRAPPIST 1d potentially being covered by a global ocean of water. The study also suggests that TRAPPIST-1b and 1c have have partially molten rock mantles, and are likely to be heavily volcanic in nature.

In publishing their work, the team are reasonably confident of their findings, but note that improved estimates of the masses of each planet can help determine whether each of the planets has a significant amount of water, allowing better overall estimates of their compositions to be made.

Continue reading “Space Sunday: rockets, exoplanets landers and asteroids” →

Space Sunday: lava tubes and politics

Posted on by Inara Pey
Lava tubes could provide ready-made tunnels for bases on the Moon and Mars – and tubes in the Canary Islands are already being used for ESA astronaut training. Credit: ESA/L. Ricci

One of the major issues in sending humans to the Moon – as the United States, China, Russia and Europe want to do (either individually or in some sort of joint venture among some of them) – is where, exactly, to send them. The Moon is an uncompromising place: without any discernible atmosphere or magnetosphere, the lunar surface is open to the full fury of both solar and cosmic radiation. This makes living there without adequate protection somewhat hazardous. Then there is the question of consumables – notably water.

Protection can be found in one of two possible ways: by covering a base under a substantial layer of lunar “soil” – more correctly called regolith – or by placing it underground. While the former is feasible, and could even be achieved via 3D printing, excavating the space needed for a base would be a hefty undertaking, requiring heavy equipment.

However, things could be eased if advantage could be taken of lunar lava tubes. These are natural conduits formed by flowing lava moving beneath the hardened surface of a previous lava flow,  draining lava from a volcano during an eruption. When the lava flow has ceased and the rock has cooled, they can form a long cave, or network of tunnels – some of which can break the lunar surface in what are called “skylights”, resembling  distinctive pits in a landscape. In recent years, over 200 of these pits have been discovered on the Moon’s near side, notably in the great lava plains around the equatorial regions, many of which have been confirmed as entrances to underground lava tubes.

Water is also present on Mars in the form of subsurface ice located around the polar regions – the only parts of the Moon where there is little or no sunlight. If it can be extracted, it could be invaluable to a human presence on the Moon: it could be purified and used for drinking; through electrolysis it could be broken down into its components, hydrogen and oxygen, with the latter used to help maintain the air within a base, the former used alongside carbon dioxide in processes for creating fuel stock space vehicles or surface craft. The difficulty is in accessing the water ice in volume. One way of doing so might be through drilling – although this would again be costly and slow. Another way might be through finding lava tubes which may have become repositories for water ice deposits. The problem is, until now, little evidence for polar region lava tubes has been found.

Philolaus Crater, roughly 70 km (40 mi) in diameter, close to the lunar North Pole, may house lava tubes that could hold the key to both the location of a future lunar base and to accessing subsurface water ice. Credit: NASA

Pascal Lee, the co-founder and chairman of the Mars Institute, a planetary scientist at the SETI Institute, and the Principal Investigator of the Haughton-Mars Project (HMP) at NASA’s Ames Research Centre – and, totally coincidentally, whom I’ve had the pleasure of meeting a number of times – reports he’s now discovered pits in the north polar region which could be indicative of lava tube skylights.

He found the pits while studying images gathered by NASA’s Lunar Reconnaissance Orbiter of the north-eastern floor of Philolaus Crater, about 550 km (340 mi) from the North Pole, on the lunar near side. They appear as small rimless depressions between 15 to 30 metres (50 to 100 ft) across, with completely shadowed interiors. Most particularly, the pits are located along sections of winding channels criss-crossing the crater floor. Called “sinuous rilles”, these are generally associated with collapsed, or partially collapsed, lava tubes, increasing the possibility they might be skylights leading to intact lava tubes.

“The highest resolution images available for Philolaus Crater do not allow the pits to be identified as lava tube skylights with 100 percent certainty,” Lee states, “but we are looking at good candidates considering simultaneously their size, shape, lighting conditions and geologic setting.”

Should they prove to be entrances to lava tubes, the pits offer an exciting prospect for lunar explorers. They could present a means to access sub-surface water ice – particularly if some of the tubes contain frozen water – which is not yet certain. They might also provide the necessary protection from radiation, making them an ideal location for a subsurface base. If there is water ice in the tunnels, solar collectors ranged on the crater floor could be used to channel heat into the tunnels to melt it, allowing it to be stored and used. A further benefit with Philolaus Crater is that it is one of the Moon’s younger craters, one of the few large craters formed during the Copernican Era formed within the last 1.1 billion years. Scientists located there would be able to study the Moon’s more recent evolution.

NASA Lunar Reconnaissance Orbiter image showing some of the newly discovered lava tube skylight candidates at Philolaus Crater. Credit: NASA/LRO/SETI Institute/Mars Institute/Pascal Lee

In terms of a location for a base, the crater has two additional benefits. The first is that as it is on the lunar near side, it will be in direct line of communication with Earth. The second is more poetic, as Lee himself notes:

We would also have a beautiful view of Earth. The Apollo landing sites were all near the Moon’s equator, such that the Earth was almost directly overhead for the astronauts. But from the Philolaus skylights, Earth would loom just over the crater’s mountainous rim, near the horizon to the south-east.

He continued, “Our next step should be further exploration, to verify whether these pits are truly lava tube skylights, and if they are, whether the lava tubes actually contain ice. This is an exciting possibility that a new generation of caving astronauts or robotic spelunkers could help address” says Lee. “Exploring lava tubes on the Moon will also prepare us for the exploration of lava tubes on Mars. There, we will face the prospect of expanding our search for life into the deeper underground of Mars where we might find environments that are warmer, wetter, and more sheltered than at the surface.”

Continue reading “Space Sunday: lava tubes and politics” →

Space Sunday: a view of Earth, a look at China, and 5 exoplanets

Posted on by Inara Pey
The Earth and Moon as seen from OSIRIS-REx. Credit: NASA/OSIRIS-REx team and the University of Arizona

NASA’s Origins, Spectral Interpretation, Resource Identification, Security – Regolith Explorer (OSIRIS-REx), launched in September 2016 is on a mission to gather samples from the surface of asteroid Bennu and return them to Earth (see my previous reports here and here). It’s a huge undertaking, one which will take the vehicle on a journey of some 7.2 billion kilometres (4.5 billion miles).

Part of this journey involved OSIRIS-REx looping past the Earth in September 2017, in a gravity assist manoeuvre design to increase its velocity by some  13,400 km/h (8,400 mph) to almost 44,000 km/h (27,500 mph), and swing it on to an intercept with the asteroid, which it will reach in October 2018. During this Earth flyby, scientists carried out an extensive science campaign, allowing them to check and calibrate the probe’s suite of science instruments.

A part of this campaign involved testing the probe’s camera system, using it to take pictures of the Earth and Moon during September and early October. Several of these images, captured on October 2nd, 2017, were used by NASA used to create a to-scale composite image of the Earth-Moon system, which was released into the public domain on January 3rd, 2018 (seen above).

At time the images were taken, the spacecraft was approximately  5 million km (3 million mi) from Earth – or about 13 times the distance between the Earth and Moon. It was created by combining pictures captured using blue, green and red filters, allowing it to present a true colour view of the Earth and Moon as they reflect sunlight. Looking at it, one cannot help by be reminded of just how small and fragile our place in the universe really is.

China’s Space Ambitions

In reporting on China’s space programme, I’ve frequently noted the growing ambitious nature of their endeavours.  A mark of this is that in 2017, China mounted more than 20 successful launches – including some for foreign nations such as Venezuela, as a part of China’s desire to expand their commercial launch operations – matching Russia’s launch efforts, and sitting not that far behind the USA.

At the start of January 2018, the China Aerospace Science and Technology Corporation (CASC) upped the ante, indicating that in 2018, they plan to carry out 35 launches through the year. At the same time, CASC’s sister organisation,  China Aerospace Science Industry Corporation (CASIC) indicated it would be carrying out at least 5 launches during the year – four of them in the span of a week – while the Chinese private sector corporation, Landspace Technology, indicated it would commence launch operations during the year. Like America’s SpaceX, Landspace plan to become a major force in commercial sector launch operations, initially with satellite payloads, but ramping to flying people into space in around 2025.

One of the more notable missions China plans to launch in 2018 is the Chang’e 4 mission to the Moon’s far side. This is a two-phase mission, commencing in June 2018 with the launch of a communications relay satellite to the Earth-Moon Lagrange point. It will be followed in December by a lander / rover combination which will land on the lunar far side to commence science studies. It will mark the first attempt to carry out long-term studies on the side of the Moon permanently facing away from Earth – not to mention the first far side lunar landing.

The Chang’e 3 lander (top) and Yutu rover share similar designs with the upcoming Chang’e 4 lunar surface mission. Credit: National Astronomical Observatories of China

The CE-4 Relay satellite is required in order for communications to take place between Earth and the Chang’e 4 lander and rover.

As the Moon is tidally locked with Earth, and always keep the same side pointed towards us, there is no way to have direct communications with any vehicle on the lunar far side. This is overcome by placing a satellite in the Earth-Moon L2 position, where it can maintain a steady position relative to the Earth and the Moon’s far side, enabling communications between the two, and keeping scientists and engineers on Earth in contact with the lander and rover.

The lander / rover combination will explore part of the 180 km (112.5 mi) diameter Von Kármán crater, believed to be the oldest impact crater on the Moon. It lies within the South Pole-Aitken Basin, a vast basin in the southern hemisphere of the far side which extends from the South Pole to Aitken crater.

The crater is of general interest because it contains about 10% by weight iron oxide (FeO) and 4-5 parts per million of thorium, which can be used as a replacement for uranium in nuclear reactors. In addition, the South Pole-Aitken Basin – one of the largest impact basins in the solar system (about 2,500 km / 1,600 mi across and some 13 km / 8.1 mi deep) – also contains vast amounts of water ice. These deposits are believed to be the result of impacts by meteors and asteroids over the aeons, which deposited ice within the basin, which lies in almost permanent shadow.

The water deposits will be part of Chang’e 4’s studies – China has already announced its intent to establish a human mission on the lunar surface, and relatively easy access to water ice could be a critical part of sustaining a human presence there. To carry out their studies, both the rover and the lander will carry a range of science instruments and experiments, including systems supplied by Sweden, Germany, the Netherlands and Saudi Arabia.

In addition, the lander will include a container with potato and rockcress seeds, together with silkworm eggs to see if plants and insects can survive in the lunar environment. It is hoped that if the eggs hatch, the larvae would produce carbon dioxide, while the germinated plants would release oxygen through photosynthesis, allowing both to establish a simple life-sustaining synergy within the container. If successful, it might allow larger biotic systems to be developed and used to augment the life support systems in a lunar base while providing additional foodstuffs.

2018 should also mark the return to flight of the Long March 5, China’s most powerful launch vehicle. This entered service in November 2016, but flights were suspended in 2017 following the failure of the vehicle’s second launch in July of that year. Long March 5 is critical to China’s ambitions, as it will be the launch platform for the Chang’e 5 (2019) and Chang’e 6 (2020) lunar sample return missions, the modules to be used in a planned space station, due to start in 2019 with the launch of Tianhe unit, and boost the Mars Global Remote Sensing Orbiter and Small Rover mission to the red planet in 2020.

A slight fuzzy TV image of the Long March 5 launch on July 2nd, 2017. The vehicle suffered “an anomaly” shortly after lift-off and eventually crashed into the Pacific Ocean. 2018 should see the Long March 5 resume operations. Credit: CCTV

The 2018 return-to-flight of the Long March 5 will likely involve placing a Dongfanghong-5 (“The East is Red”) communications satellite, which will be placed in low Earth orbit.

Continue reading “Space Sunday: a view of Earth, a look at China, and 5 exoplanets” →

Space Sunday: in memory of John Young

Posted on by Inara Pey
John Young: Gemini (l), Apollo, shuttle and in 2002, two years prior to his retirement from NASA after 42 years with the agency (r). Credit: NASA / Getty Images

On Saturday, January 6th, 2018, NASA announced the passing of astronaut John Watts Young. The US space agency’s longest-serving astronaut during his career, Young passed away on January 5th at the age of 87. He flew in space six times across three different space programmes: Gemini, Apollo and the space shuttle.

Young was born in San Francisco, California, on September 24th, 1930, and earned a Bachelor of Science degree with highest honours in Aeronautical Engineering from the Georgia Institute of Technology in 1952. He served in the US Navy from 1952 through 1962, serving as a seaborne officer prior to entering flight training , qualifying as a jet fighter pilot in 1953. After flying front-line fighters for 5 years, he joined the US Navy Air Test Centre in 1959, evaluating fighter aircraft and weapons systems.

In 1962, Young joined NASA and was part of Astronaut Group 2 alongside Neil Armstrong first man on the Moon, Charles “Pete” Conrad, commander of the first crewed Skylab mission,  Frank Borman, commander of the first Apollo flight to the Moon (Apollo 8), James “Jim” Lovell, commander of Apollo 13, Thomas Stafford, commander of the US part of the Apollo-Soyuz Test Project (ASTP) mission, and Edward “Ed” White, who was to be killed in the Apollo 1 pad fire. He was the first of that group to fly in space as a part of the Gemini programme, the second of America’s manned spaceflight programmes, and the precursor to Apollo and the lunar effort.

John Young (r) with Gemini 3 commander Virgil “Gus” Grissom, standing in front of the Gemini simulator. Credit: NASA

He first flight into space was aboard Gemini 3 on March 23rd, 1965, sitting alongside Virgil “Gus” Grissom, the mission commander. The primary goal of the mission was to put the Gemini capsule through its paces during a 3-orbit flight – America’s seventh crewed spaceflight (or ninth, if you count two X-15 flights). It was also the final mission  controlled from Cape Kennedy Air Force Station in Florida (Cape Canaveral Air Force Station today), before mission control functions were shifted to the newly opened Manned Spacecraft Centre, known today as the Johnson Space Centre.

The mission was noted for the “contraband” corned beef sandwich Young smuggled onto the flight in his spacesuit. Grissom knew nothing of the sandwich until Young produced it, and both men took a couple of bites each before Young stowed it again to avoid crumbs getting into the capsule’s electronics. Post-mission, Grissom commented, “After the flight our superiors at NASA let us know in no uncertain terms that non-man-rated corned beef sandwiches were out for future space missions. But John’s deadpan offer of this strictly non-regulation goodie remains one of the highlights of our flight for me.”

The sandwich incident seemed to leave Young sidelined; rather than being pencilled for a command slot, he was relegated to the role of back-up. However, with the Apollo programme starting to ramp-up, Ed White was rotated over to the Apollo 1 crew, and this opened a slot in the Gemini programme for Young to take the command of Gemini 10 in 1966. The 8th manned Gemini flight and with Michael Collins flying alongside Young, Gemini 10 was the first to perform a rendezvous with two Agena target vehicles.

The spacecraft launched on July 18th, 1966, 100 minutes after its dedicated Agena target vehicle. After a successful rendezous and docking, they re-ignited the Agena’s motor, the first time this had been done, and used it to raise their orbit from an average altitude of 265 km (145 nautical mile) to a 294 by 763 km (159-by-412-nautical-mile) orbit, ready for a rendezvous with the Agena target vehicle intended to be used by Gemini 8, which was unable to complete its mission. Collins then completed the first of two EVAs after the crew had rested, and then Gemini 10 detached from its own Agena to make a successful docking with the passive Gemini 8 target vehicle – the first such docking without any assistance in handling the target vehicle from Earth. After a further rest period, Collins performed a second spacewalk. With a double doubling, two EVAs and 10 science experiments, Gemini 10 was one of the most comprehensive space missions completed up to that time, with the capsule splashing down on July 21st, 1966.

John Young and Michael Collins, the crew of Gemini 10, 1966. Credit: NASA

For the Apollo programme, Young was initially assigned to back-up crews. However, following the Apollo 1 fire which killed Grissom, White and Roger Chaffee, the flight roster was reshuffled, and Young was placed on the Apollo 10 crew as Command Module Pilot. This mission, which also included Thomas Stafford and Commander and Eugene Cernan as the Lunar Module Pilot, was the final Apollo mission prior to the missions to the surface of the Moon, and was the second – after Apollo 8 –  to actually fly to the Moon.

Launched on May 18th, 1969, the only Apollo Saturn V mission to lift-off from Launch Complex 39B, and only one of two Apollo missions to feature crews who had all previously flown in space (the other being Apollo 11). Reaching the Moon on May 21st, 2969, the Apollo 10 crew became – and remain – the humans  who have travelled the farthest from their homes. This is because the Moon is in an elliptical orbit around the Earth, which varies by some 43,000 km (23,000 nmi) between perigree (the point closest to the Earth) and apogee (the point farthest from the Earth), and Apollo 10 was the only Apollo mission to take place as the Moon was approaching apogee, meaning the crew were some 408,950 km (220,820 nmi) from their homes and families in Houston.

On reaching the Moon, Young was left aboard the Command and Service Module (CSM), code-named Charlie Brown, while Stafford  and Cernan took the Lunar Excursion Module (LEM) Snoopy to some 14.4 km (8 nmi) of the lunar surface, allowing them to overfly and survey the Apollo 11 landing area in the Sea of Tranquillity. To avoid the risk of Stafford and Cernan actually landing on the Moon, the LEM had been short-fuelled, forcing them to fire the descent unit motor to start an ascent back up to orbit. However, this initially did not go smoothly.

Due to a small series of input errors by Stafford and Cernan, Snoopy’s guidance system had the craft pointing in the wrong direction, and on engine firing, the LEM went into a violent spin. It took both men several seconds to recover control – time enough for the LEM to crash on the Moon. In the event, control was regain, the decent unit was jettisoned as its feul was expended, and the ascent stage motor carried Cernan and Stafford safely to a rendezvous with the CSM. Following the excitement of the initial ascent, Stafford reported the successful rendezvous and docking by radioing Earth with the message, “Snoopy and Charlie Brown are hugging each other.”

After Apollo 10’s return to Earth on May 26th, 1969, Young started training as back-up commander for Apollo 13. When disaster stuck that mission he played a central role in the team that developed procedures to stretch the Lunar Module consumables and reactivate the Command Module systems prior to re-entry, saving the Apollo 13 crew. Young then rotated into the Command slot for Apollo 16, with LEM Pilot Charles Duke and CSM Pilot Ken Mattingly.

Apollo 16 lifted-off on April 16th, 1972, and Young and Duke arrived in the Descartes Highlands on April 21st, 1972, at the start of the second-longest lunar surface mission (Apollo 17 being the longest). In 71 hours on the Moon, conducting three extra-vehicular activities or moonwalks, totalling 20 hours and 14 minutes, driving Lunar Roving Vehicle (LRV) 26.7 km (16.6 mi) and collecting 95.8 kilograms (211 lb) of lunar samples for return to Earth. Young was the ninth man to walk on the surface of the Moon, and in typical style, was exuberant throughout: jumping clear of the surface while saluting the US flag, and setting a speed record driving the LRV.

Continue reading “Space Sunday: in memory of John Young” →

Space Sunday: helicopters, telescopes and cars in space

Posted on by Inara Pey
An artist’s impression of the Dragonfly dual-quadcopter, both on the surface of Titan and flying. The vehicle could make multiple flights to explore diverse locations as it characterises the habitability of Titan’s environment. Credit: JHU /APL / Mike Carroll

Back in August I wrote about a proposal from the Johns Hopkins Applied Physics Laboratory (APL) to fly a robotic helicopter to Saturn’s moon Titan.

Called “Dragonfly”, the mission would use a nuclear-powered dual-quadcopter, an evolution of drone technology, carrying a suite of science instruments to study the moon. Capable of vertical take-off and landing (VTOL) operations, the vehicle would be able to carry out a wide range of research encompassing Titan’s atmosphere, surface, sub-surface and methane lakes to see what kind of chemistry is taking place within them.

The proposal was one of several put forward for consideration by NASA as a part of the agency’s New Horizons programme for planetary exploration in the 2020s. In late December 2017, NASA announced it was one of two finalist proposals which will now receive funding through until the 2018 for proof-of-concept work.

Titan has diverse, carbon-rich chemistry on a surface dominated by water ice, as well as an interior ocean. It is one of a number of “ocean worlds” in our solar system that hold the ingredients for life, and the rich organic material that covers the moon is undergoing chemical processes that might be similar to those on early Earth. Dragonfly would take advantage of Titan’s dense, flight-enabling atmosphere to visit multiple sites by landing on safe terrain, and then carefully navigate to more challenging landscapes.

Dragonfly in flight. Credit: JHU /APL / Mike Carroll

At 450 kg, Dragonfly is no lightweight, and a fair amount of the mass would be taken up by its nuclear power unit. However, the vehicle will carry a science package comprising some, or all, of the following:

  • A mass spectrometer for analysing the composition of Titan’s atmosphere and surface material.
  • A gamma ray spectrometer of analysing the shallow sub-surface.
  • A seismometer for measuring deep subsurface activity.
  • A meteorology station for measuring atmospheric conditions such as wind, pressure and temperature.
  • An imaging system for characterising the geologic and physical nature of Titan’s surface and identifying landing sites.

Commenting on the NASA decision to provide further funding for the project, APL Director Ralph Semmel said:

This brings us one step closer to launching a bold and very exciting space exploration mission to Titan. We are grateful for the opportunity to further develop our New Frontiers proposals and excited about the impact these NASA missions will have for the world.

The second proposal to receive funding through until the end of 2018 is the Comet Astrobiology Exploration Sample Return (CAESAR) mission proposed by Cornell University, Ithaca, New York and NASA’s Goddard Space Flight Centre.

This mission seeks to return a sample from 67P/Churyumov-Gerasimenko, a comet that was successfully explored by the European Space Agency’s Rosetta spacecraft, to determine its origin and history. This project is being led by Steve Squyres of Cornell University, who was the principal investigator for NASA’s Mars Exploration Rover missions featuring Opportunity and Spirit.

If approved by NASA, CAESAR would launch in 2024/25, collect at least 100 g (3.5 oz) of regolith from the comet, separating the volatiles from the solid substances. The spacecraft would then head back to Earth and drop off the sample in a capsule, which would re-enter Earth’s atmosphere and parachute down to the surface in 2038. 67P/C-G was selected because it has been extensively imaged and mapped by the Rosetta mission, thus enabling engineers to design a vehicle better able to meet the conditions around the comet as it swings around the Sun.

A conceptual rendering of CAESAR orbiting comet 67P/C-G

New Frontiers is a series of planetary science missions with a cap of approximately US $850 million apiece. They include the Juno mission to Jupiter, the Osiris-REx asteroid sample-return missions, and the New Horizons mission to Pluto, also built and operated by APL. Under the terms of NASA funding, both of the 2017 finalists will receive US $4 million each in 2018, and a final decision on which will be funded through to completion will be made in 2019.

WFIRST: Hubble’s New Cousin

While attention is on the next space telescope due for launch – the ambitious James Webb Space Telescope (JWST), which will be departing Earth in 2019 – NASA and the international community is already turning its attention to the telescope that will come after JWST, with a launch due in the mid-2020s.

Billed as a cousin to the Hubble Space Telescope, and something of a descendent of that observatory, the Wide Field Infra-Red Survey Telescope (WFIRST) will use a very similar telescope system as Hubble, with a 2.4m diameter primary mirror, but with a shorter focal length. This, coupled with no fewer than 18 sensors built into the telescope’s camera (Hubble only has a single sensor), means that WFIRST will be able to image the sky with the same sensitivity as Hubble with its 300-mexapixel camera – but over an area 100 times larger than Hubble can image. To put this in perspective: where Hubble can produce a poster for your living room wall, an image from WFIRST can decorate the entire side of your house.

NASA’s Wide Field Infrared Survey Telescope (WFIRST) will fly in the mid-2020s and provide astronomers with the most complete view of the cosmos to date. Credit: NASA Goddard Space Flight Centre / CI Lab

This wide field of view will allow WFIRST to generate never-before-seen big pictures of the universe, allowing astronomers explore some of the greatest mysteries of the cosmos, including why the expansion of the universe seems to be accelerating. One possible explanation for this speed-up is dark energy, an unexplained pressure that currently makes up 68% of the total content of the cosmos and may have been changing over the history of the universe. Another possibility is that this apparent cosmic acceleration points to the breakdown of Einstein’s general theory of relativity across large swaths of the universe. WFIRST will have the power to test both of these ideas.

Continue reading “Space Sunday: helicopters, telescopes and cars in space” →

Space Sunday: reusability, habitability, survivability

Posted on by Inara Pey
SpX-13 lifts-off from Space Launch Complex 40 at Cape Canaveral Air Force Station, Florida, marking the first time SpaceX has launched a previously-flown Dragon 1 resupply capsule atop a previously flown Falcon 9 first stage, in SpaceX’s 17th launch for 2017. Credit: NASA

SpaceX Has completed its first mission to the International Space Station with a Falcon 9 first stage and a Dragon 1 resupply vehicle which have both previously flown.

The launch took place at 15:36 GMT (10:36 EST) on Friday, from Space Launch Complex 40 at Cape Canaveral Air Force Station. As well as being the first time a previously used Falcon 9 first stage and Dragon capsule have flown together, the launch also marked the first from SLC-40 since a pre-launch explosion of a Falcon 9 rocket in September 2016, which completely destroyed the rocket and its Israeli payload, and severely damaged the launch facilities.

Three minutes after the launch, the first and second stages of the Falcon 9 separated, the latter continuing towards orbit while the former performed its “boost-back” manoeuvre, and completed a safe return to Earth and a vertical landing at SpaceX’s Landing Complex 1 at Canaveral Air Force Station. The landing marked the 20th successful recovery of the Falcon 9 first stage – with 14 of those recoveries occurring in 2017.

The Dragon capsule, carrying some 2.2 tonnes of supplies for the ISS, was first used in a resupply mission in April 2015. In its current mission, it reached the station on Sunday, December 17th, where it was captured by the station’s robotic arm and moved to a safe docking at one of the ISS’s adaptors where unloading of supplies will take place. The capsule will remain at the station through January, allowing science experiments, waste and equipment to be loaded aboard, ready for a return to Earth and splashdown in the Pacific ocean, where a joint NASA / SpaceX operation will recover it.

The SpX-13 Dragon sits alongside the International Space Station on Sunday, December 17th, waiting to be grappled by one of the station’s robot arms and moved to its docking port. Credit: NASA/JSC

The mission is a significant milestone for SpaceX, bringing the company a step closer to it goal of developing a fully reusable booster launch system. Thus far the company has successfully demonstrated the routine launch, recovery and reuse of the Dragon 1 capsule and the Falcon 9 first stage. On March 30th, 2017, as part of the SES-10 mission, SpaceX performed the first controlled landing of the payload fairing, using thrusters to properly orient the fairing during atmospheric re-entry and a steerable parachute to achieve an intact splashdown. This fairing might be re-flown in 2018. That “just” leaves the Falcon 9 upper stage, the recovery of which would make the system 80% reusable.

However, recovering the second stage is a harder proposition for SpaceX – at one point the company had all but abandoned plans to develop a reusable stage, but in March 2017, CEO Elon Musk indicated they are once again working towards that goal – although primary focus is on getting the crew-carrying Dragon 2 ready to start operations ferrying crews to and from the ISS.

The major issues in recovering the system’s second stage are speed and re-entry. The second stage will be travelling much faster than the first stage, and will have to endure a harsher period of re-entry into the Earth’s denser atmosphere. This means the stage will require heat shielding and a means to protect the exposed rocket motor, as well as the propulsion, guidance and landing capabilities required for a full recovery.

SpaceX has proven the reusability of the Falcon 9 first stage (left) and the Dragon capsule system (right). All that remains is developing a reusable second stage, most likely for use with the Falcon Heavy – or as a part of the ITS / BFR. This image shows the discontinued proposal for a reusable Falcon 9 second stage. Credit: SpaceX

The problem here is that of mass. The nature of rocket staging means that – very approximately, every two kilos of rocket mass on the first stage reduces the payload capability by around half a kilogramme.  With a second stage unit, this can drop to a 1:1 ratio. So, all the extra mass of the re-entry / recovery systems can reduce the total payload mass, making the entire recovery aspect of a Falcon 9 second stage both complex and of questionable value, given the possible reduction in payload capability. However, with the Falcon Heavy due to enter service in 2018, a reusable second stage system does potentially have merit, as the combined first stages of the system can do more of the raw shunt work needed to get the upper stage and its payload up to orbit.

The Habitability of Rocky Worlds Around a Red Dwarf Star

Red Dwarf stars are currently the most common class (M-type) of star to be found to have one or more planets orbiting them. Many of these worlds appear to lie within their parent’s habitable zone, and while that doesn’t guarantee they will support life, it does obviously raise a lot of questions around the potential habitability of such worlds.

There tend to be a couple of things which often run against such planets when it comes to their ability to support life. The first is that often, they are tidally locked with their parent star, always keeping the same face towards it. This creates extremes of temperature between the two side of the planet, which might as a result drive extreme atmospheric storm conditions. The second is – as I’ve noted in past Space Sunday articles – red dwarf stars tend to be extremely violent in nature. Their internal action is entirely convective, making them unstable and subject to powerful solar flares, generating high levels of radiation in the ultraviolet and infra-red wavelengths. Not only can these outbursts leave planets close to them subject to high levels of radiation, they can cause the star to have a violent solar wind which could, over time, literally rip any atmosphere which might otherwise form away from a planet. This latter point means that one of the most vexing questions for those studying exoplanets is how long might such worlds retain their atmospheres?

In an attempt to answer to that question, planetary astronomers have turned to a planet far closer to us than any exoplanet: Mars.

Continue reading “Space Sunday: reusability, habitability, survivability” →