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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
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oon Land ng
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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.
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ovember 2018 17
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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.
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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.
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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
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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.
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/
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.
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