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The Next Mo Who do you think will be the next country to land a spacecraft on the moon? If you said any of the usual suspects – the USA, Russia, China or perhaps even India, the chances are you will be wrong. If all goes to plan, the next country to land their own spacecraft on the moon will be Israel – population just 8.5 million! by Dr David Maddison 16  S 16 Silicon iliconCChip hip Australia’selectronics electronicsmagazine magazine Australia’s siliconchip.com.au oon Land ng S o far, there have been four countries that have landed spacecraft on the moon. The first country to land an unmanned spacecraft on the moon was the Soviet Union in 1959 with Luna 2, followed by a series of US and Soviet landings and then the first manned landing by the United States in 1969. India performed a controlled crash impact in 2008 which was followed by China’s landing of an unmanned spacecraft in 2013; the first soft landing on the moon since the Soviet Union’s Luna 24 in 1976. Even though Australia has never joined this august group, it once had a space program – which mostly started and stopped in 1967 with the launch of WRESAT (as described in SILICON CHIP in October 2017 – www.siliconchip. com.au/article/10822). That demonstrated that small to medium-size countries could launch satellites. Similarly, Israel with an area of just over 20,000km2 and population much smaller than Australia (in fact, it has about the same population as New York City) has a space program – it has to date launched around 19 satellites (not counting nanosatellites). It is the smallest country with an ability to launch its own satellites, one of only 11 countries to be able to do so. And so, the next country to land a spacecraft on the moon is expected to be Israel with a planned launch in late 2018 or early 2019 and an expected landing in mid-2019. The initial plan was to launch in December 2018 and make a landing in February 2019 but delays unrelated to the Israeli lander have pushed it back by a few months (see http:// siliconchip.com.au/link/aalj for more details on the delay). Artist’s impression of Israel’s SpaceIL Sparrow craft on the surface of the moon. siliconchip.com.au Australia’s electronics electronics magazine magazine Australia’s NNovember ovember 2018  17 2018  17 Other competitors for the XPRIZE In February 2011 a total of 32 teams had registered for the Google Lunar XPRIZE but by 31st December 2016, only five teams had fulfilled the XPRIZE requirement of having a verified launch contract and became contenders for the prize. Apart from SpaceIL, these teams were Moon Express (USA; plans to launch 2019), Synergy Moon (International, negotiating to launch together with Team Indus), Hakuto (Japan, plans to launch 2020) and Team Indus (India, plans to launch 2019). The Israeli lunar program is mostly privately funded and run by the non-profit organisation SpaceIL (www. spaceil.com/). SpaceIL was initially formed to compete for the Google Lunar XPRIZE, a prize for landing a privately funded spacecraft on the moon, travelling 500 metres on the lunar surface and transmitting high-resolution video and images back to Earth. Additional prizes were available for roving more than 5000 metres, capturing pictures of man-made objects on the moon or surviving a lunar night. The goal of the Lunar XPRIZE was similar to the Ansari XPRIZE, ie, to encourage private investment in low-cost space launch vehicles and spacecraft. Since no team could meet the deadline for the XPRIZE of a launch attempt by 31st March 2018, the US$30 million pool of prize money went unclaimed. But the XPRIZE Foundation announced on 5th April 2018 that the prize would be reinstated without the cash reward. Regardless of the availability of the XPRIZE prize money, which was much less than the mission cost in any case, SpaceIL continues to prepare for the mission. SpaceIL was founded by three young engineers: Yariv Bash, Kfir Damari and Yonatan Winetraub. They discussed the idea in a pub in Holon on a winter night in 2010 and decided to win the XPRIZE as a matter of national pride for Israel. SpaceIL is mostly privately funded by various organisations and individuals including billionaire and former SpaceIL chairman Morris Kahn, who has donated US$28 million toward the US$88 million program cost. They also received a US$16.4 donation million from the Dr. Miriam & Sheldon G. Adelson Family Foundation. Other major donors include the Charles and Lynn Schusterman Family Foundation and the Parasol Foundation. There are also donors from academia, the aerospace industry, the telecommunications industry and educational institutions. Objectives While one of the original objectives for the SpaceIL mission was to win the XPRIZE, they also have other objectives. One of these is to inspire children to “think differently about science, engineering, technology and math” by creating an “Apollo effect”. Another objective is to acquire scientific data about the moon’s magnetic field. A further objective is to develop new space technologies. SpaceIL also intends to show the world that you don’t Artist’s rendering of the Sparrow lander showing the main spacecraft components. 18 Silicon Chip Australia’s electronics magazine siliconchip.com.au The planned trajectory of the lunar probe. This route uses the gravitational slingshot effect which takes longer but is much more energy efficient. See videos: “SpaceIL Trajectory” siliconchip.com.au/link/aalk and “SpaceIL Landing Plan” siliconchip.com.au/link/aall. Also see video “Spacecraft’s Orbit” siliconchip.com.au/link/aalm . have to be a superpower to land on the moon (an important lesson for Australia) and that it can be done on a small budget and with private funding. For more information on their mission, see this video: “SpaceIL Presents: The Mission” siliconchip.com.au/link/ aalp take pictures on the moon. It has solar panels for power. The reason for the large amount of fuel is that this spacecraft will only be delivered into Earth orbit by its launch rocket and it will then have to make its own way to the moon. The space vehicle Sparrow will be launched on a SpaceX Falcon 9 rocket that will also be carrying other payloads including a communications satellite into geosynchronous orbit. It will be the first time a “rideshare” is used to launch a spacecraft that is destined to travel beyond low Earth The lander that SpaceIL have developed is called Sparrow and is about is 2m in diameter, 1.5m tall and will weigh 585kg at launch; 400kg of that weight is propellant. Its scientific payload includes a magnetometer and cameras to The ride (Above and right): views of the Sparrow lander during assembly. Visible are some solar panels at top, spherical fuel tanks in middle, gold thermal control material, reddish-brown thrusters, various wiring looms (many not yet connected or secured) and structural components. Barely visible is the bottom of the main engine nozzle at bottom centre. The fuel mass is the vast majority of the mass of the spacecraft. Note that the grey frame component with the diagonal members is a support structure and not part of the spacecraft. siliconchip.com.au Australia’s electronics magazine November 2018  19 Landing and stability tests of a prototype SpaceIL lander. orbit. The “rideshare” service is facilitated by a company called Spaceflight (http://spaceflight.com/) which specialises in acquiring capacity on commercial launch vehicles and selling it on to customers “in the most expeditious and cost-effective manner possible”. [For details about the Falcon 9 see the article in last month’s issue of SILICON CHIP (October 2018.)] The spacecraft will not fly directly to the moon like the Apollo spacecraft but will conduct a number of engine burns to place the lander in an increasingly eccentric orbit around the Earth, which will eventually be large enough to also encompass the moon. These engine burns are also designed to correct any orbital inaccuracies. This is a much-more-energy-efficient scheme than the direct route, saving weight and fuel and greatly reducing the cost of the launch. This type of manoeuvre is called gravity assist (or a gravitational slingshot) and was most famously used by the Mariner 10 and Voyager interplanetary probes. The downside of using this technique is that the SpaceIL mission journey to the moon will take about two and a half months rather than a few days. As mentioned earlier, the SpaceIL lander will be one of several payloads on the Falcon 9 rocket. The lander will be released first, to be placed in orbit around the Earth in preparation for its trip to the moon, while other unrelated payloads will continue on into geostationary transfer orbit. Once the Sparrow lander is in orbit around the moon, that orbit will be circularised at an altitude of 100km, at which point the spacecraft is travelling at 7000km/h. It will then initiate a deceleration burn, reducing its altitude to 15km. Then the landing sequence will commence. The tallest mountain on the moon is 6.5km high so it is critical to get the landing location correct. The rocket engines will be turned off 10 metres above the lunar surface and then the Sparrow will free fall to the ground. The timing of the landing is critical and is designed to coincide with sunrise on the moon, as the low angle of the sunlight will increase the visibility of obstacles due to the Artist’s rendering of the SpaceIL lander at the moment of separation from the Falcon 9 second stage, which will then take other unrelated payloads into to geostationary transfer orbit or geostationary orbit as part of a “rideshare”. Illustrations depicting the operation of the OpNav (left) and Earth Moon Sensor (right) camera-based navigation systems The trajectory and landing 20 Silicon Chip Australia’s electronics magazine siliconchip.com.au Sparrow fuel tanks being integrated with the spacecraft chassis. There are four fuel tanks, two for oxidiser and two for propellant. The tanks are made of titanium, less than 1mm thick, and contain a system to minimise sloshing of the fuel which would destabilise the spacecraft. The system also separates liquid from gas to prevent entry of gas bubbles into the engine. The orange elements affixed to the tanks are heaters, part of the spacecraft’s thermal control system, to keep the fuel at an appropriate temperature. long shadows they will be casting. Bear in mind that a lunar day lasts 29.5 Earth days so this occurrence only occurs about monthly in Earth terms. The lander has an artificial intelligence optical hazard detection system, rather than traditional radar, that will help it identify hazards such as large rocks or craters and avoid them during the landing process. This optical landing system was developed by a biomedical scientist specialising in brain control processes. Imagery from the descent will also be transmitted to ground controllers back on Earth. This is critical since, after landing, the Sparrow will take off again and travel 500 metres in a single “hop”. It will need to avoid any nearby obstacles during the hop. This hop is a fundamental requirement to win the XPRIZE. Sparrow will reignite its engine and rise 220 metres into the air, landing 500 metres from its original landing point. Heating of the spacecraft by the Sun will also be a problem when it is on the moon. The fuel tanks will still contain some fuel set aside for the hop and if they reach 50°C, The Sensonor STIM300 Inertial Measurement Unit used on the spacecraft. siliconchip.com.au A rendering of the SpaceIL magnetometer experiment. Lunar magnetic fields are to be measured during landing, after landing and during the subsequent 500 metre “hop”. The spacecraft portrayed in this graphic is an earlier prototype but the experiment is the same. See siliconchip.com.au/link/aalq there is a chance they will explode. This temperature is estimated to be reached three days after landing, so the hop must be completed within that time. After the hop, there will be little or no fuel left in the tanks so there will be no risk of explosion. Choosing a landing site Naturally, a spacecraft doesn’t just land anywhere, The landing site must be carefully selected in advance based on a number of constraints. Firstly, the size of potential landing sites were selected as a circular area, 15km in diameter with suitable properties in terms of rock abundance, topographic variation, albedo Map of potential lunar landing sites with the three strongest candidate sites circled. Colours indicate the strength of the magnetic field. Image courtesy Y. Grossman, O. Aharonson and A. Novoselsky. siliconchip.com.au/link/aaln Australia’s electronics magazine November 2018  21 (reflection of solar radiation), slopes and surface roughness. Areas with rocks larger than 10cm diameter were avoided. Topographic variation was to be minimised within specified limits. Albedo is important because the lander uses a laser altimeter, so the lunar surface must have a suitable level of reflectance. Steep slopes are avoided to prevent the lander from tipping over and surface roughness should be minimal Additional considerations were made for surface temperature and communications (ie, radio visibility between the lunar and Earth uplink and downlink sites). After sites were selected according to the above criteria, they were then culled based upon SpaceIL’s scientific objective of characterising the crustal magnetic field. So areas with particular magnetic field interest were chosen as candidate landing sites leaving three main options. The magnetometer experiment Unlike the Earth, the moon has only a very weak magnetic field and does not have a geodynamo of circulating molten iron such as gives rise to the magnetic field on Earth. What magnetic field does exist on the moon arises mainly from the magnetisation of crustal rocks and this varies according to location. The history and origin of the lunar magnetic field is still unclear, hence the desire to acquire magnetic field data as part of the SpaceIL mission. The experiment to obtain magnetic field data is known as the Lunar Magnetometer or LMAG. A magnetometer is a device to measure magnetic fields (it is also commonly found on smartphones). In fact, we have an article on two magnetometer (eCompass) chips in this very issue, starting on page 72. Lunar magnetic fields have been measured before; Apollo astronauts measured fields but only near their landing sites. NASA’s Lunar Prospector measured fields globally but only at relatively low resolution, as the readings were taken from orbit. SpaceIL will build on these results by taking magnetic field readings from a range of heights as the spacecraft descends, when it lands and when it makes the 500-metre hop to its second location. Earth Moon Sensor and OpNav. The star tracker is a camera which takes pictures of the stars and compares them with a database of (typically) 57 particular stars commonly used for spacecraft navigation in order to determine the orientation and attitude of the spacecraft. Once it has identified several of those stars in its field of view, by comparing their positions to the information in its database, it can figure out its orientation. The Sparrow will use a Berlin Space Technologies ST200 star tracker which is one of the smallest and lightest such devices available. It was originally designed for CubeSats and weighs just 40g. It draws just 650mW from a 3.7V 5.0V supply The Inertial Measurement Unit will be used at all phases of SpaceIL’s flight, landing and its hop on the moon to measure the acceleration and rotation due to engine and thruster operation. It can also be used as a navigation backup in the event of failure of the star tracker. It contains three MEMS (microelectromechanical systems) gyros representing three axes, three accelerometers and three inclinometers. The Earth Moon Sensor is a unique camera and software package which will take pictures of the Earth and moon and identify them according to their size and colour. It can then locate the centres of both bodies, enabling the spacecraft to determine its position with respect to both. OpNav is a newly developed optical navigation system that takes pictures of the moon and transmits the images to Earth whereby the spacecraft position is determined by comparing the images with existing maps. Communications The transceiver used by the lander was developed by the US company Space Micro. It operates in the 2- 4GHz Sband. The receiver section operates at 2025MHz-2120MHz and the transmitter section at 2200MHz-2300MHz. It is based on Space Micro’s μSTDN-100 transponder. The data sheet for the device the transceiver is based on can be downloaded from siliconchip.com.au/link/aalh Navigation Spacecraft computer The Sparrow lander has several elements to its navigation system. These are a star tracker, an Inertial Measurement Unit and unique software based systems called the The Sparrow uses a GR712RC dual-core LEON3FT SPARC V8 processor, which is a high-reliability, fault- tolerant, radiation-hardened processor designed for space ap- The Berlin Space Technologies ST200 star tracker, shown against an Australian $2 coin (20.5mm diameter) for size comparison. The Space Micro transceiver used by SpaceIL. The tubes are waveguides for the high frequency RF signals. 22 Silicon Chip Australia’s electronics magazine siliconchip.com.au / STOP PRESS: Elon Musk (SpaceX) announces first “lunar tourist” The mission computer (an early prototype board from September 2012). plications. It is capable of clock speeds up to 100MHz and performance of 200MIPS and 200MFLOPS peak. The processor is fabricated by Tower Semiconductors Ltd. in Israel. Comparison between the computing power in the Sparrow and the miniscule amount in the Apollo spacecraft, including those which transported men to the moon, are enlightening. (It’s often claimed that today’s mobile phones have significantly higher computing power than did the Apollo craft!). Spacecraft cameras If only to prove it was there(!), arguably one of the most important elements of the spacecraft are its cameras. The camera model chosen (Berlin Space Technologies ST200) has two video processors for redundancy in the event of a failure of one processor, has 8MP (greater than 4K) resolution, an autofocus lens, can work within the temperature range of -120°C to +120°C and weighs 130g. The lens elements are made of borosilicate glass due to its low coefficient of thermal expansion. Further to our feature last month – “Reusable Rockets” (www.siliconchip.com.au/Article/11257), Elon Musk told the world’s press on September 17 that Japanese IT billionaire Yusaku Maezawa would be the first paying customer on SpaceX’s first Big Falcon Rocket (BFR) around-the-moon project. The commercial site-seeing expedition would take about a week to travel the 770,000km (480,000 mile) round trip to the moon. Maezawa stated that he wanted to take along a range of creative people – artists, writers, photographers, etc to record the event for posterity. Musk also revealed the target launch as just five years away, during 2023. During that press event, he showed off new renderings of the launch system, along with a few photos of the work going on inside SpaceX’s spaceship-building tent at the Port of Los Angeles. These were the first new details about SpaceX’s rocket construction since April, when SpaceX revealed they were building the carbon-fibre spacecraft using a 40-foot-long, 30-foot-wide cylindrical tool (12m x 9m). SpaceX appear to be using a new technique for carbon-fibre construction. Whereas carbon-fibre technology usually has tapes woven into a fabric the soaked with a resin, experts believe the BFR is being built with unwoven tapes wrapped around a giant mandrel, then soaked with the epoxy resin. They maintain that this should result in a craft which has the highest stiffness and strength, without the kinking or wrinkling of woven tape. With an estimated development cost of $US5 billion, the BFR appears to be in direct competition with NASA, currently building a giant, one-use launcher called Space Launch System. However, research, development and construction costs of this craft may be more than $US20 billion and about $US1 billion to launch. Early reports suggest that once the SpaceX BFR spacecraft is operational, it may cost the company as little as tens of millions to refuel and launch – again and again. SC Preserving the early lunar landing sites The XPRIZE offered a US$4 million bonus for photographing other man-made objects left on the moon. This caused alarm amongst some, concerned that historic landing sites (especially the Apollo sites) would be ruined by such visitation. The concern about preserving these sites led to The White House Office of Science and Technology Policy (OSTP) releasing a report on the matter, “Protecting & Preserving Apollo Program Lunar Landing Sites & Artifacts” (available via siliconchip. com.au/link/aalo). Preservation of these sites will require international cooperation. siliconchip.com.au Australia’s electronics magazine November 2018  23