Developments in Space Policies, Programmes and Technologies Throughout the World and in Europe

Abstract

The major space policy developments worldwide were presented in Chap'. 1, above, to identify the principal space faring nations’ strategies in 2016. In the section below, there will be a brief discussion of developments in technology-related areas, including policies and access to space technologies. The aim of this section is to clarify how these strategies interact with and influence specific space programmes and related research and development projects.

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1 Space Policies and Programmes

The major space policy developments worldwide were presented in Chap. 1, above, to identify the principal space faring nations’ strategies in 2016. In the section below, there will be a brief discussion of developments in technology-related areas, including policies and access to space technologies. The aim of this section is to clarify how these strategies interact with and influence specific space programmes and related research and development projects.

2 Space Transportation

2.1 Europe

With Europe’s launch sector in the midst of a substantial reorganization to increase its competitiveness in the global market, the Arianespace launch consortium aims to increase the launch rate of its Vega launcher to benefit from economies of scale and increased demand. The per-launch cost of the Vega launcher is expected to decrease as its prime contractor Avio SpA ramps up production to enable three launches per year. The Vega launcher is sold by European Launch Vehicle (ELV), the public-private joint venture between Avio (70% share) and ASI (30% share). By the end of 2016, Arianespace had used two of the ten Vega rockets that it purchased from ELV in 2016 to launch five high-resolution optical EO satellites (i.e. the Peruvian government’s PerúSat 1 and four SkySat satellites for Google’s Terra Bella constellation) on 15 September 2016¹ and Turkey’s Göktürk-1 EO satellite on 5 December 2016. The latest launch marked the eighth success of the Vega launcher system since its inauguration in 2012.² The next Vega launcher will lift the Copernicus programme’s Sentinel-2B satellite into orbit in March 2017. Whereas in 2013, Vega’s backlog of four satellite launches was valued at €130 million or €32.5 million per launch; the value of a launch reached €36.4 million per launch as of June 2015.³

On 12 August 2015, ESA and CNES began developing the Ariane 6 launch pad and horizontal launcher integration facilities in Europe’s Guiana Space Centre in French Guiana Ariane 6 on 12 August 2015. While all previous European launchers have been integrated vertically and then rolled upright to the launch pad by rail, the Ariane 6 will be integrated horizontally enabling time and cost savings derived from fewer crane and hazardous moving operations and a more fluid production flow. Nevertheless, unlike spacecraft launched on other horizontally integrated launchers, including the SpaceX Falcon 9 launcher, which are stored, integrated onto the launcher and then forced to endure additional vibrations while rolled to the launch pad, Ariane 6 payloads will remain vertical, stored in their fairing and then integrated on the now vertical Ariane 6 launcher at the last moment.⁴

By the end of 2016, the Ariane 5 had a total of 76 consecutive successful launches, surpassing the record of its Ariane 4 predecessor, reinforcing its status as the hallmark of reliability – a strong motivator for commercial satellite operators. Yet, the Ariane 5 launcher has usually sold for €150 million, while its launch cost is €170 million, requiring institutional support of Arianespace of around €100 million annually.⁵ With orders for the Ariane 5 launcher booked into 2017, Arianespace and ASL aim to decrease the cost of the Ariane 5 by 5–6% in the next batch of launch orders starting in 2019 through improvements in production and operation. They also plan to raise the price for heavier satellites intended for the Ariane 5’s upper berth, as demand for that slot has increased following the recent failed launches by competitors ILS and Sea Launch. Moreover, the price for the Ariane 5’s lower berth, targeted for small satellites and telecom satellites using electric propulsion to reach geostationary transfer orbit, will be reduced to make it more competitive with SpaceX prices. Another advantage exists in the current EU-USA exchange rate that will allow customers to purchase an Ariane 5 launch with a lower value Euro.⁶ Once the Ariane 6 becomes operational in 2020, the Ariane 5 will undergo a 3-year phase out.⁷ The Ariane 64 will be capable of lifting two telecom satellites with a combined mass of 9500 kg to geostationary transfer orbit and will be sold for €96.34 million per launch (or €48.17 million per customer).⁸ The 62 configuration of the Ariane 6 with two boosters for small satellites will be priced around €75 million.⁹

2.2 United States

NASA’s Space Launch System (SLS) heavy-lift launcher is scheduled to launch its first mission, Exploration Mission 1 (EM-1, in late 2018). While uncertainty about the launch date remained due to delays in the delivery of ESA’s Service Module, which had completed its critical design review in mid-2016 but had some technical issues that required further study, progress in the development of the various launch vehicle, spacecraft and ground system components needed to support the EM-1 enabled mission planners to confirm that the mission could take place between September and November 2018.¹⁰ Instead of arriving in January 2017, the Service Module is now expected to be delivered in April 2017, giving mission planners a large window to correct any issues faced in integrating all components of the launcher and spacecraft. The Service Module will power the Orion MPCV during its unmanned EM-1 mission. Moreover, the EM-1 mission will carry 13 cubesats as secondary payloads that will be released from a ring linking the SLS’s upper stage with the Orion MPCV.¹¹

On 23 December 2016, US President Obama signed the National Defense Authorization Act for Fiscal Year 2017 (NDAA-17) which repealed a provision in the previous year’s NDAA permitting the use of the Russian-built RD-180 engine for the US Evolved Expendable Launch Vehicle (EELV) programme with the exception of orders or options for RD-180 engines already awarded under a contract signed on 18 December 2013 and for contracts for the use of a total of 18 additional RD-180 engines between the date of the enactment of the NDAA-2017 and ending 31 December 2022.¹² Russia’s 2014 incursion in Ukraine has stoked continuing tensions between the USA and Russia that led the US Congress to prohibit US companies from contracting with Russian suppliers of rocket engines or renewing current contracts for space launch activities.¹³ Since ULA uses RD-180 engines for the first stage of its Atlas 5 launcher, the restriction limited its use before ULA’s follow-on Vulcan launcher – powered by Blue Origin’s BE-4 engine – is ready in 2022. The result is that while ULA has an exemption for the 34 RD-180 engines that were ordered while the NDAA-15 was still pending¹⁴ and the 20 more RD-180 engines ULA had ordered by 23 December 2015,¹⁵ the NDAA-17 gives ULA access to 18 more RD-180 engines in order to remain competitive with SpaceX.¹⁶

2.3 Russia

On 28 April 2016, Russia’s far east Vostochny Cosmodrome, conducted its first launch using a Soyuz 2.1a to lift two small satellites and a cubesat into LEO from its first launch pad.¹⁷ The inaugural launch was delayed by a day due to a fail signal detected on one of the launcher’s automatic safety system sensors. While work on the six other pads is ongoing, with the completion of a second pad for its Angara launcher expected in 2021, the Cosmodrome is expected to eventually host ten launches per year.¹⁸ The construction of the Cosmodrome has been accompanied by reports of construction being behind schedule, billions of dollars of budget overruns and cases of embezzlement and the non-payment of workers for months at a time. For instance, while the first launch pad was supposed to be completed by mid-2015 and supposed to be just $1.9 billion in today’s prices, by mid-2016 work on the first launch pad was still ongoing, and its cost was estimated to have exceeded $2.4 billion. Moreover, around $165 million was embezzled during the construction process, and several contractors have been charged according to Russian prosecutors. Amid the increasing costs, more than 350 workers brought public attention to the fact that there was a 4-month delay in getting paid.¹⁹ The final construction stage of the Vostochny Cosmodrome will develop facilities for a super-heavy launch vehicle that will be capable of delivering 120–150 tons into low Earth orbit by 2020.²⁰

While Russia intends to increase the role of the Vostochny Cosmodrome in civilian launches, it also intends to continue its launches from Baikonur, Kazakhstan. On 26 December 2016, Russia and Kazakhstan signed a cooperation agreement extending Russia’s use of Kazakhstan’s Baikonur Cosmodrome.²¹ The agreement regulates continued cooperation at Baikonur and includes an 8-year road map up to the year 2025. It also lists areas where space cooperation can be profitable from an economic standpoint, including remote sensing, communications and satellite navigation technologies and the development of a commercial space launch infrastructure (i.e. spacecraft, launch systems and other space-related equipment and ground-based space infrastructure) to launch spacecraft, scientific equipment and manned space flights.²² The Baikonur Cosmodrome is jointly managed by Roscosmos and Russia’s Aerospace Forces, and it is leased by Russia until 2050 at a cost of $115 million per year.²³ Moreover in 2017, Russia aims to conduct 15 launches from the Baikonur Cosmodrome in Kazakhstan, in addition to 2 launches from its Vostochny Cosmodrome and 6 from its Plesetsk Cosmodrome in Russia.²⁴

2.4 Japan

JAXA is developing its H3 next-generation launcher to be more powerful and cost-effective than its current H-2A launcher. On 20 July 2016, JAXA released the basic design of the H3, which aims to be ready for its first launch in 2020. The H3 will have several configurations including two types of fairings, two to three units for the first-stage engines and either zero, two or four solid rocket boosters depending on the payload sizes and their orbits.²⁵ Its manufacturer, Mitsubishi Heavy Industries, plans to use components from other domestic industries and will apply a flow-line manufacturing system to halve the current cost per orbital launch to around $47 million.²⁶

Japan conducted a second launch of its recent three-stage solid-fuel Epsilon launcher on 20 December 2016, with the ‘Exploration of energization and Radiation in Geospace’ (ERG) scientific satellite on board.²⁷ The Epsilon launcher is also being developed to cut launcher costs, using the same solid-fuel strap-on booster as on the H-2A.²⁸ The first launch of the Epsilon launcher was conducted on 14 September 2013, yet Japan has sought to perfect the launch capability of the launcher in the following years. The enhanced Epsilon launcher is designed to be capable of placing a 1.2 ton payload in low Earth orbit (LEO) and 700 kg payload into sun-synchronous orbit (SSO).²⁹

2.5 China

China conducted the maiden launch of its two-stage Long March 7 on 25 June 2016, carrying a prototype version of its future next-generation crew vehicle (NGCV).³⁰ Launched from the newly constructed Wenchang Satellite Launch Centre on the north-eastern coast of Hainan Island, the Long March 7 has a launch capacity of 13.5 metric tons to LEO and will eventually be used to launch taikonauts and cargo resupply missions to China’s future Tiangong space station.³¹

2.6 India

By the end of 2016, India’s PSLV launcher had conducted 6 additional launches, increasing its launch record to 38 consecutive successes out of 39 launches in total.³² Capable of lifting 3700 kg to LEO and 800 kg to GEO, the PSLV has launched a total of 84 satellites for customers, including 30 satellites launched into LEO and 3 satellites to GEO in 2016 alone. In addition to its successful track record, with just one failure in its inaugural launch in 1993, the launcher’s low cost is another drawing feature, dropping to as low as €26 million in December 2015.³³ Incidentally, India’s low cost launch capacity, and India’s refusal to sign a commercial launch accord with the US government to ensure fair market-based pricing, is the reason US companies have been restricted from using the PSLV in the past decade.³⁴

India is also nearing completion of its Geosynchronous Satellite Launch Vehicle (GSLV)-Mark III. ISRO conducted its third and final ground test of its indigenous upper-stage engine CE-20 on 19 February 2016, successfully firing the liquid-hydrogen-fuelled engine for 640 s.³⁵ While ISRO had hoped to launch its fully developed GSLV-Mark III launcher carrying the GSAT19 weather satellite by December 2016, the launch was postponed and will take place sometime in 2017.³⁶

ISRO successfully launched a Reusable Launch Vehicle (RLV) Technology Demonstration mission on 22 May 2016. First conceived by ISRO in 2009, the long delayed first flight test of the scramjet propulsion system took place at the Satish Dhawan Space Centre. Perched atop a HS9 solid booster, the 1750 kg technology demonstrator was launched to an altitude of 70 kms to autonomously test the RLV’s hypersonic aerodynamic properties, avionics, thermal protection and control systems and its mission management. This initial mission will be followed by a landing experiment, a launch to orbit and return mission and a scramjet propulsion demonstration.³⁷

3 Space Science and Exploration

In this section, space science is understood to mean using mainly remote observation to make discoveries on the origin, evolution and the future of the universe, its galaxies, our solar system and other celestial bodies, e.g. stars, exoplanets, comets and asteroids. Space exploration, on the other hand, involves human and robotic spaceflight missions. While traditional governmental space agencies dominate in both these fields, progress in the latter category can be seen with the development of exploration involving commercial players and with new space powers demonstrating the technology needed to carry out such missions.

3.1 Human Spaceflight Activities

Human spaceflight was focused on low Earth orbit (LEO), with the International Space Station (ISS) at centre stage, following its formal extension to 2024. Russia is currently the sole launch provider capable of transporting crew regularly to the ISS. It also provides ISS cargo resupply services, along with US commercial resupply services (CRS) by SpaceX and Orbital ATK, with Japan’s H-II Transfer Vehicle (HTV) providing auxiliary support. Activity with China’s space station also occurred in 2016.

ESA astronauts Tim Peake and Thomas Pesquet journeyed to the ISS in 2016. They are among ESA’s latest class of astronauts, along with Luca Parmitano, Alexander Gerst, Samantha Cristoforetti and Andreas Mogensen, who had completed their training on 22 November 2010.³⁸ These latter mentioned astronauts had, respectively, participated on the station in Expeditions 36/37, 40/41 and 42/43 and the tail end of Expedition 44.

ESA astronaut Tim Peake began his 6-month Expedition 46/47 mission on the ISS under the mission banner ‘Principia’ on 15 December 2015. Days after his arrival, on 21 December 2015, Tim Peake assisted in a spacewalk with NASA astronauts Tim Kopra and Station Commander Scott Kelly to move an equipment carrier on the station.³⁹ On 15 January 2016, Tim Peake conducted the first spacewalk for a British astronaut on the ISS, when he and Tim Kopra participated in a near-5-h spacewalk to replace a sequential shunt unit that had been damaged in November 2015. The ISS has a total of eight such units which transfer the electrical power generated by the solar panels; this replacement restored the ISS to 100% of its operational capability. The spacewalk was supposed to last for more than 6 h but was cut short when Tim Kopra reported water in his helmet, while the astronauts conducted their next task of laying cables in advance of new docking ports and the reinstallation of a valve that had been removed for the relocation of the Leonardo module in 2015.⁴⁰ In addition to serving as flight engineer and conducting dozens of experiments on the station, Tim Peake assisted in berthing the Cygnus CRS spacecraft to the ISS on 26 March 2016, and he took the lead in berthing the eighth Dragon CRS spacecraft on 10 April 2016.⁴¹ While on the ISS, Tim Peake operated a rover across a simulated Mars terrain in Stevenage, UK; he was also the second ESA astronaut to use the Mares muscle-measurement unit that charts the muscle speed and torque of a bending elbow or knee joint.⁴² And while he expected to return to Earth on 5 June 2016, the Principia mission was extended until 18 June 2016 because ground control aimed to keep the ISS operating at full capacity with six crew members closer to when the next Expedition arrived on 7 July 2016.⁴³

ESA astronaut Thomas Pesquet began a 6-month Expedition 50/51 mission on the ISS under the mission banner ‘Proxima’ on 19 November 2016. While Thomas Pesquet is the last of ESA’s 2010 astronaut graduates to fly into space, he is the first French astronaut to visit the ISS since the installation of the Columbus module in 2008. Thomas Pesquet will perform about 50 scientific experiments for ESA and CNES and will take part in many research activities for the other station partners.⁴⁴ In January 2017, Thomas Pesquet and NASA astronaut Shane Kimbrough will perform two spacewalks on the ISS, under the guidance of fellow ESA astronaut Luca Parmitano at NASA’s mission control in Texas, USA, to replace older-technology batteries with newer lithium-ion designs.⁴⁵ Moreover, following the completion of Thomas Pesquet’s mission, ESA astronaut Paolo Nespoli will return to the ISS to participate in Expedition 52/53 in mid-2017.⁴⁶

With ESA’s final Automated Transfer Vehicle (ATV) mission to the ISS completed on 15 February 2015, ESA will continue covering its dues for the ISS onward from 2017 by using the knowledge gained from the ATV programme to build the European Service Module for NASA’s Orion spacecraft.⁴⁷ The Service Module will provide propulsion, electrical power and water and thermal control to the Orion spacecraft and will maintain the oxygen and nitrogen atmosphere for its crew. The first Service Module, built in Turin, Italy, initially underwent a comprehensive series of independent tests at Plum Brook in Ohio, USA, from November 2015 to 14 December 2016; the Service Module will now undergo further testing at vehicle level in conjunction with NASA’s Orion Crew Module Structural Test Article.⁴⁸ NASA will conduct the first launch of the Orion spacecraft and Service Module on its Space Launch System near the end of 2018 for a month-long un-crewed demonstration mission around the Moon. By 7 December 2016, the agencies had agreed to extend their collaboration in human space exploration, wherein ESA will provide a second Service Module to support NASA’s first crewed Orion mission, expected to launch as early as 2021.⁴⁹

Russia launched four expeditions to the ISS in 2016, including the final vehicle in the TMA-M series, and the introduction of the newly upgraded MS variant. The final Soyuz TMA-20 M mission took place on 19 March 2016 with the Expedition 47/48 crew of Aleksey Ovchinin, Oleg Skripochka and Jeffrey Williams.⁵⁰ It was followed by the debut launch of the upgraded Soyuz MS-01 spacecraft on 7 July 2016 with the Expedition 47/48 crew of Anatoly Ivanishin, Kate Rubins and Takuya Onishi⁵¹; MS-02 on 23 September 2016 with the Expedition 49/50 crew of Sergey Ryzhikov, Andrey Borisenko and Shane Kimbrough⁵²; and MS-03 on 17 November 2016 with the Expedition 50/51 crew of Oleg Novitskiy, Peggy Whitson and Thomas Pesquet.⁵³ Russia also conducted three resupply missions (including one failure) to the ISS with its Progress cargo transfer vehicles: Progress MS-02 on 31 March 2016, MS-03 on 17 July 2016 and MS-04 on 1 December 2016 (which failed to reach the ISS due to an anomaly in the launcher’s telemetry system following the ignition of its third stage – it crashed in southern Russia 4 h after launch).⁵⁴

The sixth H-II Transfer Vehicle (HTV-6) cargo resupply mission, ‘Kounotori 6’, was launched to the ISS on 9 December 2016. The launch took place as planned shortly after the failed launch of the Russian Progress MS-04 resupply mission. The HTV-6 carried 5.9 tons of cargo, including 3.9 tons of pressurized cargo (i.e. water and food supplies, system supplies and utilization and experiment-related items) and unpressurized cargo (i.e. ISS battery Orbital Replacement Units and Orbital experiment hardware).⁵⁵ The utilization and experiment-related items included seven cubesats to be deployed from the Kibo science module, an upgraded JEM Small Satellite Orbital Deployer (J-SSOD) which doubled the deployment capacity of cubesats from the Kibo module from 6 U to 12 U, the Two-Phase Flow experiment for thermal management systems, the Position-Sensitive Tissue-Equivalent Proportional Chamber (PS-TEPC) for high-precision measurements of ionizing radiation in real-time and the High-Definition TV Camera – Exposed Facility 2 (HDTV-EF2). It also delivered the Orbital Replacement Units (ORU) for the Carbon Dioxide Removal Assembly (CDRA), a crucial system for life support in the ISS, and six lithium battery ORUs to replace the nickel-hydrogen batteries currently used on the ISS, enabling the extension of ISS operations. The HTV-6 also launched the Kounotori Integrated Tether Experiment (KITE) as an on-orbit technological demonstration. In the week following its unberthing from the ISS early in 2017, the KITE will extend from the HTV-6 a 700 m electrodynamic tether (EDT) as a propulsion mechanism for alleviating growing concerns over space debris.⁵⁶ Three more HTV missions to the ISS are planned by the beginning of 2020 (i.e. HTV-7 in February 2018, HTV-8 in February 2019 and HTV-9 in February 2020); afterward an upgraded HTV-X vehicle will replace the series in 2021.⁵⁷

Lastly, while ISS operations have been extended to 2024, its utilization beyond 2024 remains open,⁵⁸ with some ISS advocates anticipating it will continue at least until 2028 with the potential to transition into a commercial station.⁵⁹ On 11 April 2016, at the 32nd Annual Space Symposium held in Colorado, USA, United Launch Alliance (ULA) and Bigelow Aerospace announced a partnership agreement to launch two of Bigelow’s inflatable B330 space habitats into low Earth orbit on two Atlas V launchers between late 2019 and 2020. The announcement came shortly after Bigelow’s BEAM module was launched aboard the SpaceX Dragon CRS-8 mission to the ISS on 8 April 2016; the BEAM module will be attached to the ISS for a 2-year experimental demonstration.⁶⁰ NanoRacks has also facilitated the use of the ISS for businesses for over 5 years, brokering the launch to the station and the release of payloads into LEO orbit. And the recently formed Axiom Space LLC, led by former NASA ISS manager, Michael Suffredini, plans to eventually develop its own commercial space station.⁶¹

China’s Tiangong 1 space lab ended its mission in March 2016, after the station stopped sending telemetry data back to Earth.⁶² The Tiangong 1 – in sleep mode after its last crew departed in June 2013 – was not planned to be a permanent orbital station; however, in September 2016, the Chinese government confirmed the concerns raised by astronomers that the dormant 8.5 ton space station would have an uncontrolled re-entry into Earth’s atmosphere in late 2017.⁶³ Moving forward, China launched its Tiangong 2 space lab on 15 September 2016 on its Long March 2F rocket from the Jiuquan Satellite Launch Center. The Tiangong 2 uses the same basic module as the Tiangong 1 space lab but will be a test bed for the rendezvous, docking and life-support technologies intended for its future planned space station. The Shenzhou-11 spacecraft, launched on 16 October 2016, delivered the first two taikonauts to the space lab for a 30-day visit. They will be followed by additional crewed and cargo resupply missions in 2017.⁶⁴ Construction of China’s space station will begin in 2018 with the launch of its experimental core module; China aims to complete construction of the space station by 2022.⁶⁵

3.2 Lunar Science

Interest in the Moon is ongoing for both its science and exploration value, in addition to being the finish line for several private space companies competing to win the Google Lunar X Prize. This year, the USA and China continued to progress towards a robotic and human lunar presence; however, budget constraints still have the potential to delay well-intentioned initiatives. Moreover, Google Lunar X Prize competitors have begun to partner up to better their odds of winning the symbolic award.

NASA’s Lunar Reconnaissance Orbiter (LRO), launched in June 2009, is scouting the Moon in preparation for future lunar exploration, including finding landing sites; locating resources such as water, ice and hydrogen; and investigating the long-term effects of the lunar environment. The LRO completed its second 2-year extended science mission in September 2016 and was extended for a third 2-year extended science mission, which will run through October 2018. This new ‘Cornerstone Mission’ will focus on three questions relevant to the US Decadal Survey goals between 2013 and 2022, including (1) Volatiles and the Space Environment, (2) Volcanism and Interior Processes and Impacts and (3) Regolith Evolution.⁶⁶ On 23 March 2015, new research published in the journal Nature provides evidence that the spin axis of the Moon shifted by about five degrees roughly 3 billion years ago, by examining the distribution of ice at each of the lunar poles. While ice can exist in permanently shadowed areas on the Moon, direct exposure to sunlight would make it evaporate into space; researchers were able to find that the path of the ice that survived this axis shift matched models predicting where the ice could remain stable.⁶⁷ On 29 April 2016, data from the LRO data allowed researchers to develop models published in various journals to explain how lunar swirls are formed, i.e. patterns which extend tens of kilometres and are peppered across the Moon’s surface in areas where ancient bits of magnetic field are embedded in the lunar crust and appear less weathered than their surroundings. While the swirls were first thought to have formed from plumes of material ejected by comet impacts or by fine dust particles lofted by micrometeorite impacts on the Moon’s surface, a third theory which seems to be supported by LRO data is that the less-weathered areas are protected by magnetic field shields embedded in the Moon’s surface which create strong electric fields that are able to deflect some of the slower-moving charged solar wind particles.⁶⁸ And on 13 October 2016, new observations by the LRO determined that the Moon’s surface experiences a heavier bombardment by small asteroids than previous models had predicted, which implies that a future lunar base may have to be made sturdier than anticipated to withstand secondary debris impacts moving at up to 500 m per second.⁶⁹

China’s Chang’e 5-TI test capsule returned to lunar orbit in the week of 12 January 2015.⁷⁰ Launched on 23 October 2014, the prototype sample-return capsule reached the Moon within a day, circling it before returning to eject its sample capsule at a higher than average velocity into Earth’s atmosphere. Following the successful release of the capsule on 1 November 2015, Chang’e 5-TI began making its way to the Earth-Moon Lagrange (L2) point on the opposite side of the Moon. Reaching L2 by late November 2015, the service module then completed three circles around that point prior to returning to lunar orbit.⁷¹ In addition to testing critical breaking manoeuvres, the Chang’e 5-TI carries a camera system that will help to identify future landing sites for the Chang’e 5 robotic sample-return mission planned for launch in the second half of 2017.⁷² This later Chang’e 5 mission will involve a soft landing on the Moon and the collection of 200 g of samples prior to bringing them to Earth.

The Google Lunar X Prize is a competition for a grand prize of $20 million and a second prize of $5 million for the first two privately funded teams to safely land on the Moon, travel at least 500 m across its surface and send high-definition video, images and data back to the Earth. In late 2013, the X Prize Foundation and Google announced a series of interim ‘milestone’ prizes available to assist the competing teams in accessing finance at a critical point in their mission timeline and to raise public excitement and support for the teams. The Google Lunar X Prize competition was extended to the end of 2017, after two teams had met the X Prize Foundation’s 16 December 2014 stipulation requiring at least one team to have made launch arrangements by the end of 2015.⁷³ Only five teams remained in the Lunar X Prize competition by the end of 2016, out of an initial 33 entrants, as competitors had until the end of the year to submit their own launch documentation to remain in the competition.⁷⁴ The Israeli team, SpaceIL was the first to be confirmed by the foundation on 7 October 2015,⁷⁵ followed by the American team Moon Express on 8 December 2015.⁷⁶ The international team Synergy Moon was the next team to have its launch contract verified by the X Prize Foundation on 30 August 2016, followed by the Indian team TeamIndus on 1 December 2016, and the German team PT Scientists which announced its launch contract on 29 November 2016 to be confirmed later in the year.⁷⁷ The American team Astrobotic Technology separated from the X Prize competition by choosing not to secure a launch at the end of 2016; Astrobotic Technology intends to fly its first mission to the Moon in 2019.⁷⁸

3.3 Mars Science

For decades the focus for Mars science has been the investigation of the planet’s habitability, in a search for the presence of water. The collected data continues to suggest that Mars was once partially covered by large oceans and that life could have been possible in many locations on the planet’s surface.

ESA’s Mars Express orbiter, launched in June 2003, continued its high-resolution imaging mission of Mars, including the mapping of its mineral composition and atmosphere and determining the structure of the subsurface to a depth of a few kilometres, the effect of the atmosphere on the surface and the interaction of the atmosphere with the solar winds. The images taken by the high-resolution stereo camera on Mars Express in mid-2015 helped to reveal in extraordinary detail complex features such as the Noctis Labyrinthus region on the western edge of Valles Marineris, an entire network of plateaus and fractures spanning around 1200 km that suggests many episodes of tectonic stretching and volcanic activity in Mars’ Tharsis region.⁷⁹ Moreover, images of the Arda Valles, north of the Holden crater and Ladon Valles, revealed a dendritic drainage system carved by vast volumes of water that once flowed from the southern highlands.⁸⁰ Images from Mars’ Colles Nili region showed the erosional remnants of a former plateau, whose layered deposits gently sloped away from the sides of the hills and the series of ridges and troughs found around the mounds and inside some of the impact craters on the channel floors. These are thought to be associated with buried ice that has since been covered over by wind-blown dust and local debris.⁸¹ And images of ridges and troughs in the western part of Acheron Fossae, 1000 km north of Olympus Mons and other volcanic giants in the Tharsis bulge, suggest a complex history, as its pattern of cross-cutting faults imply that the region experienced stresses from different directions over time; as Acheron Fossae has been likened to Earth’s continental rift system and is associated with plate tectonics, rifts are important for studies of the general evolution of the crust as well as the thermal evolution of the deeper subsurface.⁸² Additionally, plasma and solar wind measurements from Mars Express’ Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) plasma instrument suite and the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument revealed that the cloud-like plume that reached an altitude of 250 km in 2012 was likely the result of a coronal mass ejection (CME) from the Sun that was large enough to impact Mars and increase the escape of plasma from the planet’s atmosphere – adding an important angle on the potential role of space weather in how Mars may have lost much of its atmosphere in the past.⁸³

The ExoMars programme is a joint endeavour between ESA and the Russian Space Agency, Roscosmos, to addresses whether life has ever existed on Mars. The programme is comprised of two missions: the first began in 2016 with the launch of ESA’s Trace Gas Orbiter (TGO) and the Entry, Descent and Landing Demonstrator Module (EDM) ‘Schiaparelli’; and the second mission will take place in 2020 and comprises a rover and surface science platform. Both missions will be launched to Mars using Roscosmos’ Proton launcher.⁸⁴ The first ExoMars mission began its 7-month journey to Mars on 14 March 2016; on reaching a distance of 900,000 km from the planet on 16 October 2016, the TGO and Schiaparelli separated, with the TGO moving into a 4-day elliptical orbit around Mars, while Schiaparelli veered into the atmosphere to descend to Mars’ surface.⁸⁵ After separation, the TGO began a series of complex aerobraking manoeuvres that will continue over the course of 13 months to lower its elliptical orbit of 250 km by 98,000 km to a circular orbit of 00 km before its main scientific mission to analyse rare gasses in the atmosphere begins. It will also act as a data relay for surface rovers, providing two to three overflights of each Mars rover every day to send signals back to Earth. Despite being placed into safe mode for a brief period after faulty configuration of the TGO’s main engine caused a temporary glitch during preliminary testing, the TGO was performing nominally by the end of 2016.⁸⁶ Nevertheless, on 19 October 2016, Schiaparelli experienced an anomaly as it descended into Mars’s atmosphere; while its radar Doppler altimeter functioned correctly and the measurements were included in the guidance, navigation and control system, a saturation of the inertial measurement unit (IMU) occurred shortly after the parachute deployed, causing its navigation system to estimate that it was already below ground level and triggering the final landing stages, while the vehicle was at an altitude of around 3.7 km. ESA has called for an external independent inquiry board to conduct a technical investigation into the anomaly and expects to provide a full report early in 2017.⁸⁷

NASA’s Mars Odyssey mission, launched on 7 April 2001, is the longest-operating spacecraft to be sent to Mars. The Mars Odyssey mission marked a turning point for NASA in Mars exploration, after the failure of two preceding missions in 1999 prompted an overhaul of NASA’s exploration plans. While its prime mission to make the first global map of the amount and distribution of numerous chemical elements and minerals on Mars surface was completed in August 2004, its mission had been extended for 12 additional years by 2016; Mars Odyssey is also a communication relay for rovers and landers on the planet.⁸⁸ In March 2016, NASA published its most detailed gravity map of Mars, derived from Doppler and range tracking data collected by NASA’s Mars Odyssey, Mars Global Surveyor and the Mars Reconnaissance Orbiter spacecraft. The improved resolution allows researchers to better interpret how the crust of the planet has changed over Mars’ history in many regions. Moreover, by analysing tides in the crust and mantle caused by the gravitational pull of the Sun and the two moons of Mars, researchers confirmed that Mars has a liquid outer core of molten rock. Researchers also determined that during the winter season for both hemispheres within Mars’ 11-year orbit around the Sun, approximately 3–4 trillion tons of carbon dioxide, i.e. 12–16% of the mass of the entire Martian atmosphere, freezes out of the atmosphere onto the northern and southern polar caps, respectively.⁸⁹ On 26 December 2016, the Mars Odyssey spacecraft briefly put itself into safe mode due to uncertainty about its orientation with regard to Earth and the Sun – similar to a fault experienced in December 2013; following a reset of the inertial measurement unit and the circuit card that serves as interface between that sensor, the flight software and the star tracker, for determining spacecraft attitude, the orbiter’s knowledge of its orientation was restored. By 30 December 2016, Mars Odyssey had resumed communication relay assistance to Mars rovers, with science observations of Mars following shortly afterward.⁹⁰

NASA’s Mars Reconnaissance Orbiter (MRO) continued operations in 2016, providing data for the purpose of determining whether life has ever existed on Mars, characterizing the climate and geology and preparing for future human exploration. In the decade following its insertion into Mars’ orbit in March 2006, the MRO completed 45,000 orbits of Mars⁹¹; while its primary science mission ended in November 2008, the MRO is currently in its third extended mission, which began in October 2012.⁹² In March 2016, new evidence from the MRO’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument suggested that Mars’ Sisyphi Montes region, studded with flat-topped mountains, formed when volcanoes erupted beneath an ice sheet billions of years ago; the research helps show that there was extensive ice on ancient Mars and adds information about an environment combining heat and moisture that might have provided favourable conditions for microbial life.⁹³ Moreover, ‘radargrams’ produced with data from MRO’s Shallow Subsurface Radar (SHARAD) instrument confirmed previous 2003 and 2007 models that indicate that Mars’ most recent ice age ended about 400,000 years ago, as the poles began to cool and thicken relative to Mars’ equator.⁹⁴ Other clues about Mars’ climate history were revealed when images of the northern Arabia Terra region from the Context Camera and High Resolution Imaging Science Experiment camera showed the formation of runoff lakes and streams that appeared roughly billion years after an earlier era of wet conditions on ancient Mars.⁹⁵

On 5 August 2012, NASA’s Mars Science Laboratory (MSL) rover ‘Curiosity’ began its mission to address whether Mars ever had the right environmental conditions to support microbial life. It seeks to determine whether life ever arose on Mars and characterize its climate and geology to help prepare for human exploration. Its biological objectives are to determine the nature and inventory of organic carbon compounds, conduct an inventory of the chemical building blocks of life and identify features that may represent the effects of biological processes; its geological and geochemical objectives are to investigate the chemical, isotopic and mineralogical composition of Martian geological materials and to interpret the processes that have formed and modified rocks and soils; its planetary process objectives include assessing 4-billion-year timescale atmospheric evolution processes and determining the present state, distribution and cycling of water and carbon dioxide; and its surface radiation objective is to characterize the broad spectrum of surface radiation, including galactic cosmic radiation, solar proton events and secondary neutrons.⁹⁶

Curiosity began its third Martian year on 11 May 2016, having recorded environmental patterns through two full cycles of Martian seasons while crossing the Gale Crater’s rugged terrain; each year on Mars lasts 668.6 sols, with each sol lasting 39.6 min longer than an Earth day.⁹⁷ The rover continues to redefine researchers’ assumptions of Mars’ volcanic history after an analysis of a rock sample using an X-ray diffraction instrument detected significant amounts of tridymite, created when large amounts of silica are heated at extremely high temperatures; the finding suggests that Mars once had explosive volcanoes that led to the presence of the mineral.⁹⁸ Another surprise came when a study of active sand dunes at the Bagnold Dunes of Mars’ Mount Sharp showed sinuous crest lines of ripples similar to underwater ripples on Earth, with each ripple steeper than the face on the other side, instead of impact ripples formed by wind-carried sand grains colliding with other sand grains along the ground; this led researchers to believe that the mechanism forming ripples on Mars was its thicker atmosphere in the past which worked like a fluid to form smaller wind-drag ripples.⁹⁹ On 2 July 2016, Curiosity placed itself into safe mode as a precaution after experiencing an unexpected mismatch between camera software and data-processing software in the main computer; the rover had also gone into safe mode three times in 2013. The rover was taken out of safe mode in the following week and resumed full operation on 11 July 2016.¹⁰⁰ Curiosity began its second 2-year mission extension on 1 October 2016, to explore key sites on lower Mount Sharp including a ridge capped with material rich in the iron-oxide mineral hematite and an exposure of clay-rich bedrock; and additional extensions for exploring farther up Mount Sharp appear on the horizon.¹⁰¹

NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) mission aims to explore the planet’s upper atmosphere, ionosphere and interactions with the Sun and solar wind, which will be used to determine the role that the loss to space of volatile compounds from the Mars atmosphere has played in the history of Mars’ habitability.¹⁰² In March 2016, new research published in the journal Geophysical Research Letters showed how the Comet Siding Spring plunged Mars’ magnetic field into chaos as it passed within a distance of 140,000 km in October 2014. While sensitive equipment aboard MAVEN was turned off during the flyby, its magnetometer remained on to observe how the charged plasma in Mars upper atmosphere interacted with Siding Spring’s charged coma as it washed over the planet, flooding it with additional charged particles and temporarily merging the comet’s magnetic field with Mars’ weak field generated in Mars’ upper atmosphere; the effect of the plasma tide was similar to that of a strong but short-lived solar storm and likely fuelled a temporary surge in the amount of gas escaping from Mars’ upper atmosphere.¹⁰³ New images from MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) published on 19 October 2016 provided an unprecedented ultraviolet view of Mars’ nightside atmosphere verifying the presence of a ‘nightglow’ emitted from nitric oxide; the phenomenon begins with chemical reactions on Mars’ dayside as ultraviolet light from the Sun breaks down carbon dioxide and nitrogen in the upper atmosphere that are then blown around the planet and eventually descend to lower altitudes on the nightside where nitrogen and oxygen then collide to form the nitric oxide molecules that generate the ultraviolet glow from the release of additional energy. Prior to these images, the nitric oxide glow on Mars was predicted by researchers, and its presence had been detected in prior missions.¹⁰⁴

ISRO’s Mars Orbiter Mission (MOM) ‘Mangaalayan’ is the first Asian interplanetary space probe to reach the planet Mars, joining the ranks of ESA, NASA and Roscosmos; ISRO is also the first space agency to have been successful in its maiden attempt and at the frugal total cost of ₹450 crore ($73 million).¹⁰⁵ MOM lifted into space on 5 November 2013 and inserted in Mars’ orbit on 24 September 2014. While MOM’s primary mission is intended as a technology demonstration, its secondary mission is to study Mars’ surface features, morphology, mineralogy and atmosphere with its suite of five indigenous scientific instruments: the Mars Colour Camera, the Methane Sensor for Mars, the Thermal Infrared Imaging Spectrometer, the Mars Exospheric Neutral Composition Analyser and the Lyman Alpha Photometer.¹⁰⁶ While ISRO announced the first science results of the mission on 11 November 2015, on 8 December 2016, it was made known that the highly anticipated measurements of atmospheric methane (a biomarker whose presence indicates the current or historical presence of life) from MOM’s Methane Sensor for Mars (MSM) instrument might never arrive due to a flaw in the sensor design of the Fabry-Pérot interferometer, which didn’t allow for methane data alone to be extracted from carbon dioxide and other gasses in Mars’ atmosphere.¹⁰⁷ Nevertheless, the MSM is still effective as an albedo mapper and in measuring reflected sunlight.¹⁰⁸ Subsequent science data collected by all instruments of the spacecraft is still being studied and prepared for publication. Lastly, plans for a second MOM spacecraft are already underway with ISRO’s ‘announcement of opportunity’; the follow-up mission is expected to be launched in March 2018.¹⁰⁹

3.4 Mercury Science

The BepiColombo programme is a joint endeavour between ESA and the Japanese space agency, JAXA, to measure and understand the composition, geophysics, atmosphere, magnetosphere and history of the planet Mercury. BepiColombo will be Europe’s first mission to Mercury and is based on two spacecraft: the ESA-led Mercury Planetary Orbiter (MPO) and the JAXA-led Mercury Magnetospheric Orbiter (MMO). The MPO will use its instrument suite of 11 experiments and instruments to study the planet’s geology, composition, inner structure and exosphere, while the MMO has five experiments and instruments to study the planet’s magnetic field, atmosphere, magnetosphere and inner interplanetary space.¹¹⁰ The mission is expected to be launched in October 2018, having been delayed by 6 months from its earlier intended April 2018 window, after a major electrical problem in the missions’ Mercury Transfer Module (MTM) was encountered prior to a thermal test. While the postponement will have no impact on the science return of the mission, it will extend the flight time to 7.2 years, arriving in December 2025 – 1 year later than previously anticipated.¹¹¹ BepiColombo will follow in the footsteps of NASA’s MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) mission that launched in August 2004 and orbited Mercury from March 2011 until it impacted the surface of Mercury on 30 April 2015.¹¹²

3.5 Jupiter Science

NASA’s Juno mission aims to answer questions about Jupiter’s origins by observing its gravity and magnetic fields, atmospheric dynamics and composition and evolution. Launched on 5 August 2011, Juno inserted into an elliptical polar orbit around Jupiter on 4 July 2016 and aimed to conduct 37 science orbits of Jupiter over the course of 20 months, before ending its mission in February 2018.¹¹³ Its first close flyby took place on 27 August 2016, with Juno reaching a distance of 4200 km from Jupiter’s clouds, this time with its suite of eight science instruments activated to transmit data over the following days.¹¹⁴ The next close flyby took place in safe mode on 19 October 2016, after the spacecraft’s telemetry indicated that two important helium check valves in its main engine had not operated as expected, opening for several minutes rather than a few seconds as intended, during the execution of a period reduction manoeuvre (PRM); while Juno rebooted successfully in the following week and is in healthy operation, no science data was collected on that flyby.¹¹⁵ The next flyby took place on 11 December 2016, with data collected from seven of Juno’s eight science instruments – not including its Jovian Infrared Auroral Mapper (JIRAM) which was receiving a software patch at the time.¹¹⁶ NASA had decided to also forego the PRM in that third flyby, finding that it would not have affected the quality of the science collected by Juno during its closest approach; however, as the manoeuvre would have reduced Juno’s orbital period from 53.4 days to 14 days, maintaining its current path will result in around 12 science orbits instead of 37, unless the mission is extended beyond February 2018.

The next spacecraft to orbit Jupiter will be ESA’s Jupiter Icy moon Explorer (JUICE) in development under ESA’s Cosmic Vision 2015–2025 plan. Its foreseen launch date is in 2022 aboard an Ariane 5 launcher, and it should arrive at the Jovian planet in 2030. The nearly 5500 kg spacecraft will make a careful investigation of Jupiter’s three biggest moons, using the gravity of Jupiter to initiate a series of close flybys around Callisto, Ganymede and Europa, and then finally settle into an orbit around Ganymede for an 8-month study.¹¹⁷ As all three moons are suspected of having oceans of water beneath their icy crusts, scientists are trying to understand whether there is any possibility that these moons could host microbial life.¹¹⁸ On 16 July 2015, ESA selected Airbus D&S for a €350.8 million ($374 million) contract to build the JUICE Orbiter. The contract was formalized on 9 December 2015.¹¹⁹

3.6 Saturn Science

The Cassini-Huygens mission, a joint NASA, ESA and ASI mission, was launched in 1997. Reaching Saturn in 2004, Cassini went on to drop the Huygens probe onto Saturn’s moon, Titan. From there, the Cassini Solstice Mission was supposed to end in June 2008; however, funding was provided to allow continued operation to provide new insights on Saturn and its moons.¹²⁰ The Cassini mission began its final year on 14 September 2016, after more than 12 years of studying Saturn, its rings and moons.¹²¹ On 23 January 2016, Cassini took its second of five large propulsive manoeuvres using gravity assists from Titan to take the spacecraft from an equatorial orbit around Saturn to an inclination above its poles for Cassini’s ‘Grande Finale’ that will involve passes through Saturn’s rings and will end with a plunge into its atmosphere.¹²² Cassini’s final mission phase began shortly before its first close dive through the centre of Saturn’s outermost F ring on 4 December 2016; the spacecraft will make 20 of these passes until 22 April 2017 and then transition between Saturn’s innermost ring and atmosphere for an additional 22 passes, ending its mission on 15 September 2017.¹²³

A new study published in the Journal of Geophysical Research independently confirmed that Ligeia Mare, the second largest sea on Titan, is rich in methane rather than ethane, which is produced in abundance in Titan’s atmosphere. A possible explanation for the sea’s nearly pure methane composition could be that the sea is regularly replenished with fresh methane rainfall or that the denser ethane somehow drains into the larger adjacent sea, Kraken Mare. Using radar data collected from a 2013 experiment that bounced radio signals off Ligeia Mare, researchers were also able to find that its seabed is likely covered by a sludge layer of organic-rich compounds.¹²⁴ Another recent paper in the journal Geophysical Research Letters described how researchers using data from Cassini’s radar imager were able to find the first direct evidence of liquid-filled channels on Titan, along with the first observation of canyons hundreds of meters deep, indicating that it was formed from a process that was active for a long time or that the channels had eroded down much faster than other areas on Titan’s surface.¹²⁵

3.7 Solar Observation

Continued observation of the Sun’s external activity has the benefit of improving our understanding of its interior, its corona, the monitoring of solar wind and its consequences on Earth and its neighbouring planets. Coronal mass ejections (CMEs) from the Sun emit surges of charged particles in directions that may cross Earth’s path and can damage satellites, impede space-based services and affect the terrestrial electrical infrastructure.

ESA’s Project for Onboard Autonomy (PROBA)-2 microsatellite mission tracks spikes in CMEs ejecting from the Sun that have previously been seen to just skim Earth, typically bringing with them a burst of radio energy.¹²⁶ Building on nearly 8 years of successful PROBA-1 experience, the PROBA-2 continues as part of ESA’s In-Orbit Technology Demonstration Programme, whose missions are dedicated to the demonstration of innovative technologies; its payload carries 17 new technological developments and four scientific experiments.¹²⁷ Launched in November 2009, PROBA-2’s mission was once again extended on 22 November 2016; its third operational mission will continue from 1 January 2017 to 31 December 2018.¹²⁸ On 9 March 2016, PROBA-2 was able to observe a partial solar eclipse with its SWAP imager from its 800-km-altitude polar orbit; the SWAP views the solar disc at extreme ultraviolet wavelengths to capture the turbulent surface of the Sun and its swirling corona.¹²⁹ As the Sun’s 11-year activity cycle drew closer to its minimum, where the number of sun spots, active regions, solar flares and eruptions diminish, PROBA-2 was in the right position to view an annular solar eclipse on 1 September 2016. Orbiting the Earth once every 90 min, PROBA-2’s SWAP imager and its LYRA radiometer, which measures solar irradiance, managed to view four partial eclipses.¹³⁰ ESA is also developing the PROBA-3, as a pair of satellites maintaining a fixed configuration to form a 150-m-long solar chronograph to study the Sun’s faint corona closer to the solar rim than previously achieved.¹³¹ The two satellites, a coronagraph spacecraft and an occulter, will be launched together in late 2018 into a highly elliptical tandem orbit, repetitively demonstrating acquisition, rendezvous, proximity operations, formation flying, coronagraph operations, separation and convoy flying.¹³²

NASA’s Solar Dynamics Observatory (SDO) mission seeks to determine how the Sun’s magnetic field is generated and structured and how this stored magnetic energy is released in the form of the solar wind, energetic particles and variations in the solar irradiance. The spacecraft is comprised of three scientific experiments: the Atmospheric Imaging Assembly (AIA), the EUV Variability Experiment (EVE) and the Helioseismic and Magnetic Imager (HMI).¹³³ Located in a geosynchronous orbit around the Earth, SDO’s global view of the Sun facilitates research that focuses on the previously unrecorded real fine structure of the star.¹³⁴ SDO continuously observed the Sun’s activity throughout 2016, capturing images of coronal holes and solar flares and occasionally catching the transit of a planet passing in front of the star. On 9 May 2016, SDO (along with the NASA/ESA SOHO mission and the JAXA/NASA/UK Hinode mission) studied the planet Mercury as it transited between Earth and the Sun – an event that happens 13 times or so in a century. The transit helped SDO to both align and calibrate its space instruments, enabling researchers to mitigate the effect of stray light in SDO’s instruments that should otherwise have viewed the profile of Mercury transiting the Sun without a glow surrounding its circumference. SOHO used the transit opportunity to measure the Sun’s rotation axis.¹³⁵ On 2 August 2016, SDO entered inertial mode as the Moon transited the Sun; while its HMI and EVE instruments came back online within 2 days of the transit, a temporary glitch in SDO’s AIA instrument delayed full science mode operations until 10 August 2016.¹³⁶ And in research published on 11 October 2016, scientists using SDO and IRIS data were able to observe certain frequencies of solar seismic waves channelling upwards through the chromosphere and corona atmospheric layers into the Sun’s photosphere. The technique gives scientists a new tool to understand the Sun’s lower atmosphere and also might help to address a long-standing question in solar physics regarding excess heat in the Sun’s corona, which is about 100 times hotter than the chromosphere below, with waves possibly from reflecting back and contributing to the heat in some way.¹³⁷

The Solar and Heliospheric Observatory (SOHO) mission is a joint collaboration between ESA and NASA to study the Sun from its deep core to the outer corona and the solar wind. Launched in December 1995 for a 3-year mission that was meant to end in 1998, its success prompted several mission extensions with operations continuing throughout 2016.¹³⁸ SOHO orbits around the Sun in step with the Earth, at a distance of 1.5 million kilometres from Earth, enabling an uninterrupted view of the star.¹³⁹ SOHO’s mission was once again extended on 22 November 2016 and will continue from 1 January 2017 to 31 December 2018.¹⁴⁰ In anticipation of Mercury’s 9 May 2016 transit past the Sun, two of SOHO’s twelve instruments, the Extreme ultraviolet Imaging Telescope (EIT) and the Michelson Doppler Imager (MDI), were restored to full operation, after a 5-year dormancy, to take measurements of the event.¹⁴¹ On 4 August 2016, SOHO caught the demise of a Kreutz-type comet that plunged too close to the Sun in its highly elliptical orbit.¹⁴² Lastly, a paper appearing in Astronomy and Astrophysics on 6 June 2016 summarized research on a new model, based on data collected from SOHO and STEREO, to map out where solar energetic particles (SEPs) might be found as they spread out and travelled away from the Sun; the model takes into consideration the fact that turbulence in solar material can cause magnetic field lines to wander, showing SEPs taking a much wider path than previous models predicted and explaining how SEPs can reach the far side of the Sun.¹⁴³

NASA’s Solar Terrestrial Relations Observatory (STEREO) mission, launched on 26 October 2006, provides the first-ever stereoscopic measurements of the Sun and its CMEs. Made up of two space-based observatories, i.e. STEREO-A travelling in a smaller and faster orbit (ahead of Earth’s orbit) and STEREO-B trailing behind with a larger and slower orbit, the mission aims to understand the causes and mechanisms of CME initiation, characterize the propagation of CMEs through the heliosphere, discover the mechanisms and sites of energetic particle acceleration in the low corona and the interplanetary medium and improve the determination of the structure of the ambient solar wind.¹⁴⁴ While NASA mission operations had lost communication with STEREO-B on 1 October 2014, during a test of the spacecraft’s command loss timer as it neared solar conjunction, NASA managed to re-established contact with STEREO-B on 21 August 2016, following several months of attempts to contact the spacecraft without the Sun’s interference.¹⁴⁵ Despite intermittent contact with STEREO-B since that time, the operations team is still in the process of assessing the spacecraft’s health, re-establishing attitude control and evaluating all subsystems and instruments, which could take months or even years.¹⁴⁶ STEREO-A continued collecting data, having resumed normal science operations on 17 November 2015, after undergoing side lobe repointing operations on 20 August and 1 December 2014 which had the spacecraft transmit lower-resolution data for most of 2015.¹⁴⁷

JAXA’s Hinode mission, formerly Solar-B, is a joint collaboration with NASA and the UK to measure solar magnetic fields; study the generation, transport and dissipation of magnetic energy from the photosphere to the corona; and record how energy stored in the Sun’s magnetic field is released as the field rises into the Sun’s outer atmosphere.¹⁴⁸ Launched in September 2006 for a 3-year mission, the polar, Sun-synchronous orbiting spacecraft has allowed scientists to study solar phenomena, from solar explosions to the delicate motion of solar spicules, in great detail for more than 10 years, continuing beyond 2016.¹⁴⁹ In research published on 19 April 2016, scientists using Hinode, SDO and STEREO-A observations from a December 2013 solar flare were provided speed, temperature, density and size measurements that strengthened scientists’ understanding that the electromagnetic phenomenon called a ‘current sheet’ is the result of magnetic reconnection on the Sun. A current sheet is a very fast, very flat flow of electrically charged material that forms when two oppositely aligned magnetic fields come in close contact, creating very high magnetic pressure that is unstable and can lead to new configurations; with the heat and light from the transformation producing a solar flare. As current sheets and magnetic reconnection are so closely associated, such detailed observations bolster the idea that magnetic reconnection is the force behind solar flares.¹⁵⁰

NASA’s Interface Region Imaging Spectrograph (IRIS) satellite is a Small Explorer mission to observe how solar material moves, gathers energy and heats up as it travels through the Sun’s lower atmosphere. Its mission, launched in June 2013 and operating in a polar, Sun-synchronous orbit, complements the SDO and the Hinode missions to explore the Sun’s variable atmosphere and how it impacts Earth; that is, while SDO and Hinode monitor the photosphere (solar surface) and corona (outer atmosphere), IRIS observes the chromosphere and transition region between. In addition to being where most of the Sun’s ultraviolet emission is generated, this region powers the Sun’s million-degree atmosphere and drives the solar wind. Like with the SDO spacecraft, IRIS used the transit of Mercury in front of the Sun to help recalibrate its telescope to correct any changes that might have occurred during its launch into orbit.¹⁵¹ IRIS observed a mid-level solar flare on 24 July 2016, capturing how large amounts of magnetic energy are released, heating the Sun’s atmosphere and releasing energized particles out into space, which in turn drives post-flare loops of plasma (i.e. coronal rain) to puzzlingly rapidly cool from millions down to a few tens of thousands of kelvins while descending to the photosphere.¹⁵² While IRIS’s prime mission was for 2 years, it has been extended through September 2018, with the possibility of additional extensions afterward.¹⁵³

NASA’s Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) focuses on the basic physics of particle acceleration and energy release in solar flares. Launched in February 2002 for a 2-year mission, RHESSI has operated for more than 14 years and underwent its fifth month-long detector anneal from 23 February to 29 April 2016. An annual procedure involves heating up detectors to rejuvenate them from accumulated radiation damage and then cooling them back down to operating temperatures for the spacecraft to resume collecting solar X-ray and gamma-ray data.¹⁵⁴

3.8 Solar System Science

The dwarf planet Ceres and near-Earth objects (NEOs) including comets and asteroids were the central focus for exploration in 2016.

NASA’s Dawn mission studies the asteroid Vesta and dwarf planet Ceres, the two largest bodies in the asteroid belt between Mars and Jupiter (with average diameters of 525 km and 950 km, respectively), to characterize the early solar system and the processes that dominated its formation. Launched on 27 September 2007, Dawn inserted into orbit around Ceres on 6 March 2015.¹⁵⁵ In the following months, Dawn mapped Ceres with increasing detail as it lowered its orbit from 4400 km on 7 June 2015 to 1470 km on 25 August 2015 to its final orbit of 380 km on 26 October 2015.¹⁵⁶ Capturing images at a resolution of 35 m per pixel, Dawn’s visible and infrared mapping spectrometer (VIR) enables scientists to identify specific minerals by their reflected wavelength, while data from its gamma ray and neutron detector (GRaND) provides details on Ceres’ composition and on the abundances of elements in its surface.¹⁵⁷ Observations of the domed 3-km-tall Ahuna Mons in Ceres’ bright Occator crater revealed an abundance of bright material on some of its slopes and less on others.¹⁵⁸ While ice has been located near the surface and in cold traps in permanent shadow on Ceres, the bright material in the crater is likely to be highly reflective salts.¹⁵⁹ The intricate geometry of the crater’s interior and of Ahuna Mons suggests that geologic activity occurred in the recent past; moreover, studies of Ahuna Mons have led researchers to conclude the domed mountain to be the first known example of a cryovolcano that erupts a liquid made of volatiles such as water in the form of a salty mud mix, instead of silicates. Researchers have also found evidence that Ceres might once have had a weak temporary atmosphere.¹⁶⁰ Dawns’ prime mission ended on 30 June 2016; its extended mission phase began in the following month with an elliptical orbit of 7200 km to view the dwarf planet from a higher vantage.¹⁶¹

ESA’s Rosetta mission to perform a detailed study of the comet 67P/Churyumov-Gerasimenko concluded on 30 September 2016. Launched on 2 March 2004 on Europe’s Ariane 5 launcher, the Rosetta orbiter and its Philae lander had reached the comet after a decade-long journey and became the first mission to successfully orbit a comet on 6 August 2014.¹⁶² On 12 November 2014, Philae accomplished the first successful landing on a comet, albeit bouncing twice due to a misfire of its harpoons and landing in the shadow of a cliff. Philae spent nearly 57 h performing its science objectives, managing to transmit all of the results from its final sequence of measurements before its battery ended.¹⁶³ From there, contact was established sporadically before the comet’s closest approach to the Sun in August 2015. In the following months, ESA and the DLR extended Rosetta’s mission into September 2016 to monitor the comet’s evolution as it journeyed deeper into the solar system. In a study published in the journal Nature, researchers using data from Rosetta’s RSI instrument confirmed that the comet’s low density was likely due to a porous mixture of dust particles and ice rather than a cavernous interior, consistent with earlier results from Rosetta’s CONSERT radar experiment.¹⁶⁴ Additional studies published throughout 2016 addressed the detection of magnetic field-free cavities and its association with outgassing¹⁶⁵ and how the colour of the comet changes following a pass around the Sun, as surface dust is ejected – lifted by the sublimated ice beneath it.¹⁶⁶ Prior to the end of its mission, on 2 September 2016, Rosetta’s OSIRIS narrow-angle camera had captured images of the Philae lander at 5 cm per pixel, providing the precise location and a contextual conclusion to the data generated in Philae’s journey.¹⁶⁷ In the following weeks, the Rosetta spacecraft was set on a collision course with the Ma’at region of the comet’s small lobe which plays an important role in the comet’s activity, to study the comet’s gas, dust and plasma environment near its surface and for very high-resolution images.¹⁶⁸

NASA’s reboot of the Wide-field Infrared Survey Explorer (WISE) mission, this time to discover and characterize near-Earth objects (NEOs) with infrared light, was reactivated in September 2013 for 3 additional years of service.¹⁶⁹ The original WISE mission was completed early in 2011 and was placed in 31 months of hibernation after surveying the whole sky twice in infrared light.¹⁷⁰ Now dubbed NEOWISE, soon after the mission began its third year of operation at the start of 2016, NASA released its latest data from the spacecraft, having detected and characterized 72 NEOs (eight of which being potentially hazardous asteroids (PHA)), bringing the total number of known NEOs to 439.¹⁷¹ The NEOWISE mission continued its search through 2016, spotting a comet C/2016 U1 (NEOWISE) on 21 October 2016 and another ‘2016 WF9’ NEO likely with cometary origins on 27 November 2016 – the trajectories of both objects appear not to threaten Earth in the near future.¹⁷² In January 2016, a new study published in the Astrophysical Journal Letters added to findings on the most luminous galaxy, W2246-0526, which belongs to a new class of extremely luminous infrared galaxies (ELIRG). Discovered using WISE data in 2015, W2246-0526 shines with the light of more than 300 trillion suns, some 12.4 billion light-years from Earth, and is thought to have a behemoth black hole at its centre that is heating surrounding gasses to temperatures of millions of degrees and blasting out high-energy, visible, ultraviolet and X-ray light, as it sucks in matter. The researchers studying W2246-0526 found large amounts of ionized carbon in a very turbulent state throughout the entire galaxy, instead of flowing in specific directions from the black hole’s accretion disc, suggesting that the momentum and energy of the particles of light deposited in the gas are so great that they are pushing the gas out in all directions; should all the gas and dust eventually blow out of the hot, dust-obscured galaxy (hot DOG), the quasar surrounding the black hole would likely be visible.¹⁷³

Commercial interest in NEOs has increased in recent years with several private US companies already investing millions of dollars to be the first to mine asteroids. As an initial step, Planetary Resources and Deep Space Industries (DSI) business models focus on developing prospecting spacecraft that will image and characterize promising asteroids. On 16 July 2015, Planetary Resources launched its Arkyd 3 Reflight (A3R) spacecraft from the ISS to validate several core technologies that will be incorporated into a future fleet of Arkyd spacecraft that will be launched into the solar system.¹⁷⁴ Similarly, DSI is developing its FireFly spacecraft; but rather than testing its technologies in Earth orbit, the first-generation spacecraft will be launched directly towards promising asteroids. The main focus in asteroid mining is in the potential availability of rare metals that could be returned to Earth or water that could be converted into propellant and oxygen for deeper space exploration. While initial estimates of the value of some known asteroids are upwards of $100 trillion, to reach these caches, both companies will need to invest substantial resources in developing the necessary mining technology, in addition to successfully rendezvousing and securing a spacecraft onto an asteroid’s surface.¹⁷⁵

3.9 Outer Solar Science

ESA’s Gaia mission is measuring the positions and motions of more than 1 billion stars of the roughly 100 billion stars in our galaxy to create the most accurate map yet of the Milky Way. Launched on 19 December 2013 and operating from the L2 Lagrange point, the spacecraft completed the second year of a 5-year survey on 16 August 2016.¹⁷⁶ On 14 September 2016, ESA published the first catalogue based on data collected during its first 14 months of science operations, which feature the density of stars across the entire sky and the parallax, i.e. the apparent motion of a star against a distant background, of more than two million stars. While the image contained stripes and other artefacts, these will gradually fade in subsequent scans as the trace amounts of ice deposits which remained in the spacecraft following its commissioning will be outgassed using heaters beneath Gaia’s mirrors.¹⁷⁷ In the lead up to the publication, ESA released a sonification, converting astronomical data into sound, to portray the status of astrometric catalogues prior to the advent of Gaia and demonstrate the remarkable progress that was being made in the field of astrometry.¹⁷⁸ Researchers scrutinizing Gaia data have detected over a thousand transient bright astronomical sources, due to stars undergoing a major outburst or supernova, but in July and August 2016, they observed two rare instances of gravitational microlensing, where the gravity of a massive object between a star and observer causes the path of its light to distort. The first instance, classified as Gaia16aua, observed a faint star of magnitude 19 suddenly brighten by two magnitudes, while the second instance, classified as Gaia16aye, observed the anomalous peaks and troughs in brightness of a magnitude 14.5 star; by pairing Gaia measurements with ground-based data, researchers will be able to estimate the position and mass of objects (e.g. a star or black hole) causing the gravitational microlensing with high precision.¹⁷⁹

NASA’s Kepler mission to discover hundreds of Earth-size and smaller planets in or near the habitable zone of more than 150,000 stars and determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets began in May 2009. By May 2013, the loss of two of the four reaction wheels on the spacecraft brought an end to Kepler’s 4-year science mission as the spacecraft had lost its ability to precisely point at the original field of view; but by May 2014, NASA had approved the Kepler 2 (K2) community-driven mission which repurposed Kepler to accurately point at target sky fields along the ecliptic plane of Earth’s orbit using the Sun to maintain its stability. The K2 mission is expected to continue operations into 2018.¹⁸⁰ By the end of 2016, continued analyses of Kepler data had revealed more than 5100 planet candidates, with more than 2500 verified planets¹⁸¹; K2 added another 447 candidates, with 154 verified planets by mid-year.¹⁸² As at 24 August 2016, 22 planets were known to be Earth-sized and orbiting within the habitable zone of their nearest stars.¹⁸³ In May 2016, a new study of the Kepler-223 star system showed its four planets to have the same configuration as that of Jupiter, Saturn, Uranus and Neptune in the early history of our Sun’s solar system; but whereas our the orbit of planets in the solar system have evolved since its birth 4.6 billion years ago, the much older Kepler-223 system appears to have maintained a single orbital configuration resonating around its star for far longer. As resonances are extremely fragile, it’s possible that interactions with numerous asteroids and planetesimals may have dislodged the Sun’s giants from their own resonance.¹⁸⁴ Another recent study published in the Astrophysical Journal measured the orbits of 19 heartbeat star systems that were identified by the Kepler mission; because these binary systems are in elongated elliptical orbits, the diameters of the stars tend to rapidly fluctuate at the point of their closest encounter due to the tidal forces caused by each star’s gravitational pull. While the tidal stretching of these heartbeat stars should have quickly caused their systems to evolve into circular orbits, the researchers postulate that third or fourth stars might exist in these systems that have gone undetected, which may be maintaining these highly stretched-out, elliptical orbits.¹⁸⁵

NASA’s Spitzer Space Telescope, launched in August 2003, studied the early universe, young galaxies and forming stars and was used to detect dust discs around stars.¹⁸⁶ After running out of the coolant needed to chill its longer-wavelength instruments in 2009, Spitzer was repurposed to track exoplanets around stars with the use of infrared light. As exoplanets cross in front of their stars, they block out a fraction of the light, allowing the size of the planet to be revealed, in addition to giving clues about the planet’s atmosphere by the infrared light that they also emit.¹⁸⁷ In March 2016, Spitzer data helped researchers to create the first temperature map of an Earth-like exoplanet that is double in size and tidally locked to its star; rather than having a thick atmosphere with winds moving heat around the planet as previously thought, the exoplanet was seen to inefficiently transport heat, and lava flows likely warmed the nightside of the planet.¹⁸⁸ Another planet-finding technique used by Spitzer is called microlensing, which occurs when the light of a distant star is magnified and brightened by the gravity of another star that passes in its foreground. Should the closer star have a planet in its orbit, the planet might cause a blip in the magnification. By mid-2015, Spitzer had viewed a total of 142 microlensing events¹⁸⁹; moreover, in late 2016 NASA’s Spitzer and Swift space telescopes were used to observe a microlensing event of a newly discovered brown dwarf, OGLE-2015-BLG-1319, marking the first time two space telescopes have collaborated to observe a microlensing event, rather than pairing observations with a ground observatory.¹⁹⁰ Spitzer’s mission was extended for 2.5 years beginning on 1 October 2016 and continuing through the commissioning phase of the James Webb Space Telescope in early 2019.¹⁹¹ This ‘Beyond’ phase will explore a wide range of topics in astronomy and cosmology, as well as planetary bodies in and out of our solar system.¹⁹²

China’s Dark Matter Particle Explorer (DAMPE) mission was successfully launched to a 500 km Sun-synchronous orbit on 17 December 2015. Its 3-year mission aims to shed new light on the nature of dark matter – a hypothetical kind of matter (along with dark energy) that could explain where the remaining estimated 85% of the total mass energy in the universe exists. The DAMPE mission searches for dark matter by measuring the properties of particles that annihilate or decay in space, as with experiments conducted inter alia by the Alpha Magnetic Spectrometer (AMS) on board the ISS or the CALorimetric Electron Telescope (CALET) recently attached to Japan’s Kobo module. However, DAMPE extends the search into the multi-TeV region with an energy resolution of 1.5% at 100 GeV (i.e. at least three times higher than international peers) and will also take precise measurements of the flux of nuclei with a spectrum up to above 100 TeV (i.e. nine times wider than the AMS), to gain insight into the origin and propagation of high-energy cosmic rays.¹⁹³ In the initial 2 years of its mission, DAMPE will scan space in all directions, followed by another year or more that will focus on areas where the potential signatures of dark matter are most likely to be observed.¹⁹⁴ By 19 December 2016, the spacecraft had collected 1.8 billion cosmic rays, with more than 1 million high-energy electrons among the collected particles. The mission’s first results are expected to be published in early 2017.¹⁹⁵

ISRO’s Astrosat mission, launched on 28 September 2015, is India’s first astronomy satellite to provide optical, ultraviolet and X-ray images of black holes and other related phenomena over the course of 5 years.¹⁹⁶ Its first scientific results and the future scope were presented on 29 September 2016 at the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, India; with the spacecraft having orbited the Earth more than 5400 times, executing 343 individual pointings to 141 different cosmic sources.¹⁹⁷ Included among the findings, Astrosat’s Large Area X-ray Proportional Counter (LAXPC) instrument observed for the very first time rapid variability of high-energy (particularly >20 keV) X-ray emissions from the enigmatic ‘GRS 1915 + 105’ black hole system. These quasi-period oscillations are thought to occur because the inner part of the disc surrounding the black hole wobbles as the spinning black hole drags the space-time fabric around it, as predicted by Einstein’s general theory of relativity. While these oscillations have been studied in the past in low-energy X-rays, observing phenomenon also in high-energy X-rays from higher energy photons that are emitted closer to the black hole allows researchers to measure the arrival time difference between the energy bands and provides clues to the geometry and dynamic behaviour of the gas swirling around a black hole.¹⁹⁸ The spacecraft began its Open Phase observations based on proposals by numerous institutions on 1 October 2016.