Have you read the top Pixalytics blogs of 2017?

World Cloud showing top 100 words from Pixalytics 2017 blogs

In our final blog of the year, we’re looking back at our most popular posts of the last twelve months. Have you read them all?

Of the top ten most read blogs, nine were actually written in previous years. These were:

You’ll notice that this list is dominated by our annual reviews of the number of satellites, and Earth observation satellites, orbiting the Earth. It often surprises us to see where these blogs are quoted and we’ve been included in articles on websites for Time Magazine, Fortune Magazine and the New Statesman to name a few!

So despite only being published in November this year coming in as the fourth most popular blog of the year was, unsurprisingly:

For posts published in 2017, the other nine most popular were:

2017 has been a really successful one for our website. The number of the views for the year is up by 75%, whilst the number of unique visitors has increased by 92%!

Whilst hard work, we do enjoy writing our weekly blog – although staring at a blank screen on a Wednesday morning without any idea of what we’ll publish a few hours later can be daunting!

We’re always delighted at meetings and conferences when people come up and say they read the blog. It’s nice to know that we’re read both within our community, as well as making a small contribution to informing and educating people outside the industry.

Thanks for reading this year, and we hope we can catch your eye again next year.

We’d like to wish everyone a Happy New Year, and a very successful 2018!

Earth observation satellites in space in 2017?

Artist’s rendition of a satellite – paulfleet/123RF Stock

Earth Observation (EO) satellites currently account for just over a third of all the operational satellites orbiting the Earth. As we described two weeks ago, according to the Union of Concerned Scientists database there were 1 738 operational satellites at the end of August 2017, and 620 of these have a main purpose of either EO or Earth Science.

This represents a massive 66% increase in the number of EO satellites from our 2016 update, and the percentage of overall active satellites is also up from one quarter. These figures demonstrate, once again, that EO is a growing industry.

What do Earth observation satellites do?
Looking more closely at what EO satellites actually do demonstrates that despite increases in satellite numbers in almost all categories, it’s clearly growth in optical imaging which is the behind this significant increase. The purposes of active EO satellites in 2017 are:

  • Optical Imaging: 327 satellites representing a 98% increase on last year
  • Radar imaging: 45 satellites, a 32% increase on last year
  • Infrared imaging: 7 satellites, no change to last year
  • Meteorology: 64 satellites, a 73% increase on last year
  • Earth Science: 60 satellites, a 13% increase on last year
  • Electronic intelligence: 50 satellites, a 6% increase on last year
  • 14 satellites with other purposes, a 133% increase on last year
  • 51 satellites simply list EO as their purpose, a 100% increase on last year

Who controls Earth observation satellites?
Despite the huge increase in EO satellites, the number of countries who control them has not seen the same growth. This year there are 39 different countries listed with EO satellites, an increase of only 15% on last year. In addition, there are satellites run by multinational agencies such as the European Space Agency (ESA).

The USA leads the way controlling over half the EO satellites, although this is largely due to Planet who account for 30% on their own! Following USA is China with 14.4%, and then come India, Japan and Russia who each have over 3%.

The USA is followed by China with about 20%, and Japan and Russia come next with around 5% each. The UK is only listed as controller on 4 satellites all related to the DMC constellation, although we are also involved in the ESA satellites.

Size of Earth observation satellites
It’s interesting to look out the size breakdown of these satellites which shows the development of the small satellite. For this breakdown, we’ve classed satellites into four groups:

  • Large satellites with a launch mass of over 500kg
  • Small satellites with a launch mass between 100 and 500 kg.
  • Microsats with a launch mass between 10 and 100 kg.
  • Nanosats/Cubesats with a launch mass below 10 kg.

For the current active EO satellites there are:

  • 904 large satellites equating to 52.01%
  • 178 small satellites equating to 10.24%
  • 145 microsats equating to 8.34%
  • 409 Nanosats/Cubesats equating to 23.53%
  • The remaining 102 satellites do not have a launch mass specified.

Who uses the Earth observation satellites?

There has also been significant movement in the breakdown of EO satellites users since 2016. The influence of small commercial satellites undertaking optical imaging is again apparent. In 2017 the main users for EO were:

  • Commercial users with 44.68% of satellites (up from 21% in 2016)
  • Government users with 30.81% (down from 44% in 2016)
  • Military users with 19.45% (down from 30% in 2016)
  • Civil users with 5.16% (approximately the same as in 2016)

It should be noted that some of these satellites have multiple users.

Orbits of Earth observation satellites
In terms of altitude, unsurprisingly the vast majority, 92.25%, of EO satellites are in low earth orbits, 6.45% are in geostationary orbits and 1.3% are in an elliptical orbits.
There is a much greater variation in type of orbits:

  • 415 in a sun-synchronous orbit
  • 234 in a non-polar inclined orbit
  • 17 in a polar orbit
  • 8 in an equatorial orbit
  • 5 in an elliptical orbit
  • 5 in a Molniya orbit (highly eccentric elliptical orbits of approximately 12 hours)
  • 45 satellites do not have a type of orbit listed

Few interesting facts about active Earth observation satellites

  • Oldest active EO satellite is the Brazilian SCD-1 Meteorology/Earth Science satellite.
  • Valentine’s Day (14th February) 2017 saw Planet launch its Flock 3P meaning that 88 active EO satellites were launched on that day.
  • Most popular launch site is Satish Dhawan Space Centre operated by Indian Space Research Organisation (ISRO) who have put 169 into space.
  • ISRO’s Polar Satellite Launch Vehicle is also the most popular launch vehicle with 114 satellites.
  • The EO satellite furthest away from the Earth is the USA’s Electronic Intelligence satellite Trumpet 3 which has an apogee of 38 740 km.

What’s next?
It’s not clear whether the rapid growth in the number of EO satellites will continue into 2018. Planet, one of the key drivers, announced earlier this month that they had successfully completed their objective to image the globe’s entire landmass every day – which is a massive achievement!

That’s not say that Planet won’t push on further with new ideas and technologies, and other companies may move into that space too. China launched a number of EO satellites last weekend and there are already a number of interesting satellites planned for launch between now and the middle of 2018 including, Cartosat-2ER, NovaSAR-S, GOES-S and Sentinel-3B to name a few. .

One thing is for certain, there is a lot collected EO data out there, and it is increasing by the day!

Flip-Sides of Soil Moisture

Soil Moisture changes between 19th and 25th August around Houston, Texas due to rainfall from Hurricane Harvey. Courtesy of NASA Earth Observatory image by Joshua Stevens, using soil moisture data courtesy of JPL and the SMAP science team.

Soil moisture is an interesting measurement as it can be used to monitor two diametrically opposed conditions, namely floods and droughts. This was highlighted last week by maps produced from satellite data for the USA and Italy respectively. These caught our attention because soil moisture gets discussed on a daily basis in the office, due to its involvement in a project we’re working on in Uganda.

Soil moisture can have a variety of meanings depending on the context. For this blog we’re using soil moisture to describe the amount of water held in spaces between the soil in the top few centimetres of the ground. Data is collected by radar satellites which measure microwaves reflected or emitted by the Earth’s surface. The intensity of the signal depends on the amount of water in the soil, enabling a soil moisture content to be calculated.

Floods
You can’t have failed to notice the devastating floods that have occurred recently in South Asia – particularly India, Nepal and Bangladesh – and in the USA. The South Asia floods were caused by monsoon rains, whilst the floods in Texas emanated from Hurricane Harvey.

Soil moisture measurements can be used to show the change in soil saturation. NASA Earth Observatory produced the map at the top of the blogs shows the change in soil moisture between the 19th and 25th August around Houston, Texas. The data is based on measurements acquired by the Soil Moisture Active Passive (SMAP) satellite, which uses a radiometer to measure soil moisture in the top 5 centimetres of the ground with a spatial resolution of around 9 km. On the map itself the size of each of the hexagons shows how much the level of soil moisture changed and the colour represents how saturated the soil is.

These readings have identified that soil moisture levels got as high as 60% in the immediate aftermath of the rainfall, partly due to the ferocity of the rain, which prevented the water from seeping down into the soil and so it instead remained at the surface.

Soil moisture in Italy during early August 2017. The data were compiled by ESA’s Soil Moisture CCI project. Data couresy of ESA. Copyright: C3S/ECMWF/TU Wien/VanderSat/EODC/AWST/Soil Moisture CCI

Droughts
By contrast, Italy has been suffering a summer of drought and hot days. This year parts of the country have not seen rain for months and the temperature has regularly topped one hundred degrees Fahrenheit – Rome, which has seventy percent less rainfall than normal, is planning to reduce water pressure at night for conservation efforts.

This has obviously caused an impact on the ground, and again a soil moisture map has been produced which demonstrates this. This time the data was come from the ESA’s Soil Moisture Climate Change Initiative project using soil moisture data from a variety of satellite instruments. The dataset was developed by the Vienna University of Technology with the Dutch company VanderSat B.V.

The map shows the soil moisture levels in Italy from the early part of last month, with the more red the areas, the lower the soil moisture content.

Summary
Soil moisture is a fascinating measurement that can provide insights into ground conditions whether the rain is falling a little or a lot.

It plays an important role in the development of weather patterns and the production of precipitation, and is crucial to understanding both the water and carbon cycles that impact our weather and climate.

Two New Earth Observation Satellites Launched

Artist's rendition of a satellite - paulfleet/123RF Stock Photo

Artist’s rendition of a satellite – paulfleet/123RF Stock Photo

Two new Earth observation satellites were launched last week from European Space Centre in Kourou in French Guyana, although you may only get to see the data from one. Venµs and OPTSAT-3000 were put into sun synchronous orbits by Arianespace via its Vega launch vehicle on the 1st August. Both satellites were built by Israel’s state-owned Israel Aerospace Industries and carry instruments from Israel’s Elbit Systems.

Venµs, or to give its full title of Vegetation and Environment monitoring on a New MicroSatellite, is a joint scientific collaboration between the Israeli Space Agency (ISA) and France’s CNES space agency.

Venµs is focussed on environmental monitoring including climate, soil and topography. Its aim is to help improve the techniques and accuracy of global models, with a particular emphasis on understanding how environmental and human factors influence plant health. The satellite is equipped with the VENµS Superspectral Camera (VSSC) that uses 12 narrow spectral bands in the Visible Near Infrared (VNIR) spectrum – ranging from 420nm wavelength up to 910 nm wavelength – to capture 12 simultaneous overlapping high resolution images which are then combined into a single image. The camera uses a pushbroom collection technique and has a spatial resolution of 5.3m and a swath size of 27.56 km.

Venµs won’t have full global coverage; instead there are 110 areas of interest around the world that includes forests, croplands and nature reserves. With a two day revisit time, during which time it completes 29 orbits of the planet. This means every thirtieth image will be collected over the same place, at the same time and with the same angle. This will provide high resolution imagery more frequently than is currently available from existing EO satellites. The consistency of the place, time and angle will help researchers better assess fine-scale changes on the land to improve our understanding of the:

  • State of the soil,
  • vegetation growth,
  • detection of spreading disease or contamination,
  • snow cover and glacial movements; and
  • sediment movement in coastal estuaries

A specific software algorithm has been developed for the mission to work with the different wavelengths to remove clouds and aerosols from the satellite’s imagery, giving clear images of the planet irrespective of atmospheric conditions.

The second satellite launched was the OPTSAT-3000 which is an Italian controlled optical surveillance satellite, which will operate in conjunction with the COSMO-SkyMed radar satellites giving Italy’s Ministry of Defence independent autonomous national Earth observation capability across optical and radar imagery.

This is a military satellite and so some of the details are difficult to verify. As mentioned earlier the instrument was made by Elbit systems, and the camera used usually offers a spatial resolution of around 0.5 m. However, it has been reported that the resolution will be much closer to 0.3m because the satellite is in a very low earth orbit of a 450 km.

OPTSAT-3000 will collect high resolution imaging of the Earth, it’s not clear at this stage whether any of the imagery will be made available for commercial/scientific use or purchase, although it is worth noting that COSMOS-SkyMed images are sold.

Two more Earth observation satellites launched shows that our industry keeps on moving forward! We’re really interested, and in OPTSAT’s case hopeful, to see the imagery they produce.

Queen’s Speech Targets Space

Artist's rendition of a satellite - paulfleet/123RF Stock Photo

Artist’s rendition of a satellite – paulfleet/123RF Stock Photo

Last week was the State Opening of Parliament in the UK following the General Election, this included the Queen’s Speech which set out the legislation the Government intends introduce in the coming Parliament. As expected, Brexit dominated the headlines and so you may have missed the announcement of the Space Industry Bill.

The space sector has been a growth target for the Government since 2010, when it set an ambitious target of delivering 10% of the global space economy. The last UK Space Agency report covered 2014/15 and indicated the industry was worth £13.7bn – equivalent to 6.5% of the global space economy.

Our space industry is inextricably linked to Europe through the European Space Agency (ESA). Whilst, as we have described before, Brexit won’t affect our role in ESA, other projects such as Copernicus and Galileo are EU led projects and the UK’s future involvement isn’t clear. This Bill is part of the Government’s response, and its aim is to make the UK the most attractive place in Europe for commercial space activities.

We’ve previously written about the current UK licencing and regulatory arrangements for anyone who wants to launch an object into space, as detailed in the Outer Space Act 1986. This Bill will change that framework and has the following key elements:

  • New powers to license a wide range of spaceflight activities, including vertically-launched rockets, spaceplanes, satellite operations, spaceports and other technologies.
  • Comprehensive and proportionate regulatory framework to manage risk.
  • Measures to regulate unauthorised access and interference with spacecraft, spaceports and associated infrastructure.
  • Measures to promote public safety by providing a regulatory framework to cover operational insurance, indemnity and liability.

The Bill itself is based on the draft Spaceflight Bill published in February, together with the Government responses to the twelve recommendations of the Science and Technology Committee Report on the Draft Spaceflight Bill which was issued on the 22nd June.

There are still a number of questions to be answered over the coming months.

  • Limited Liability: Currently, the standard requirement is to have insurance of at least €60 million. However, the draft Bill suggests that insurance requirements will be determined as part of the license application process. Clearly, the different types of spaceflight will have different risks and so having flexibility makes sense; however, until the industry understands this aspects it will be a concerning area of uncertainty.
  • Spaceports: Previously, the Government intended to select a location for a spaceport, but last year this changed to offering licences for spaceports. This means there could be multiple spaceports in the country, but it is questionable whether there is sufficient business to support multiple sites. Given the specialist knowledge and skills needed to launch spacecraft, it is likely that a preferred site will eventually emerge, with or without Government involvement.
  • Speed of Change: Back in 2012 the Government acknowledged that regulations for launching objects into space needed to be revised as they didn’t suit smaller satellites. Since that time satellites have got even smaller, constellation launches are increasing rapidly and costs are decreasing. The legislation and regulations will need to evolve as quickly as the technology, if the UK is to be the most attractive place to do business. Can we do this?

The UK Space Industry is in for a roller coaster over the coming years. Brexit will undoubtedly be challenging, and will throw up many threats; whereas the Space Industry Bill will offer opportunities. To be successful companies will need to tread a careful path.

UKSEDS National Student Space Conference 2017

The 2017 UKSEDS National Student Space Conference took place last weekend at the University of Exeter and I was delighted to be asked to give a presentation.

UKSEDS, the acronym of the ‘UK Students for the Exploration and Development of Space’, is a charity dedicated to running events for space students and graduates. It is the UK branch of global community who have the aim of promoting space, space exploration and research.

The National Student Space Conference is in its 29th year, and 2017 was the first time I’d attended. I began the Saturday morning with a panel discussion on Exploration versus Exploitation with Dr David Parker from the European Space Agency, Cathrine Armour who leads the South West Centre of Excellence in Satellite Applications and Andy Bacon from Thales Alenia Space UK.

One of the key points raised in the panel surrounded the topic’s title, and that it wasn’t a contest between exploration and exploitation, but rather that exploration is generally followed up with exploitation e.g. even in the 19th and 20th century explorations were politically motivated. However exploration is risky, and so it may be difficult to produce favourable outcomes that can be exploited.

Traditionally, commercial organisations were risk averse and therefore exploration has often been supported by public bodies. The exploitation came later from commercial organisations, but there’s now an increased appetite for risk through venture and crowd funding with space being a particular focus.

We also have hindsight of how we’ve altered planet Earth, and so need to apply this to space where we’ve completed our first survey of the solar system. Exploitation may not be far away as there are companies already aiming to mine asteroids, for example. So alongside investing in science and technology, we also need to invest in the governance to ensure that any future exploitation is undertaken responsibly.

Closer to Earth, it can be considered that we’ve not yet fully exploiting the potential of orbiting satellites. For example, we could use them for generating solar energy as a twenty four hour resource. So whilst exploration does tend to proceed exploitation, in fact it is probably more accurate to say we loop between the two with each providing feedback into the other.

My presentation session was between the coffee break and lunch. I was last up and followed Cathrine Armour, Matt Cosby from Goonhilly Earth Station Ltd and Dr Lucy Berthoud from the University of Bristol & Thales Alenia Space UK. My presentation was on “Innovations in Earth observation” and can be found here.

I particularly enjoyed Lucy’s talk where she posed the question – Is there life on Mars? She also had a crowd pleasing set of practical experiments involving dry ice and a rock from a local beach, which was a bit daunting to follow! Whilst Lucy concluded that Mars has the elements needed for life to exist in terms of nutrients, an energy source and liquid water, any life would likely to be microscopic.

However, there are large costs associated with us visiting Mars to confirm this. Ignoring the obvious cost of the flight, the decontamination aspect is huge. As mission planners have to avoid both forward and backward contamination, i.e., us contaminating Mars and the material brought back contaminating the Earth. This brings us back around to the morning panel and why exploration always tends to come first, supported by national or international bodies.

Overall, I had a great time at the Conference and would wholly recommend any students who have interest in space join UKSEDS. Membership is free and it can give you access to great events, opportunities and contacts. You can join here!

Have you read the top Pixalytics blogs of 2016?

Artist's rendition of a satellite - paulfleet/123RF Stock Photo

Artist’s rendition of a satellite – paulfleet/123RF Stock Photo

As this is the final blog of the year we’d like to take a look back over the past fifty-two weeks and see which blog’s captured people’s attention, and conversely which did not!

It turns out that seven of the ten most widely viewed blogs of the last year weren’t even written in 2016. Four were written in 2015, and three were written in 2014! The other obvious trend is the interest in the number of satellites in space, which can be seen by the titles of six of the ten most widely read blogs:

We’ve also found these blogs quoted by a variety of other web pages, and the occasional report. It’s always interesting to see where we’re quoted!

The other most read blogs of the year were:

Whilst only three of 2016’s blogs made our top ten, this is partly understandable as they have less time to attract the interest of readers and Google. However, looking at most read blogs of 2016 shows an interest in the growth of the Earth Observation market, Brexit, different types of data and Playboy!

We’ve now completed three years of weekly blogs, and the views on our website have grown steadily. This year has seen a significant increase in viewed pages, which is something we’re delighted to see.

We like our blog to be of interest to our colleagues in remote sensing and Earth observation, although we also touch on issues of interest to the wide space, and small business, communities.

At Pixalytics we believe strongly in education and training in both science and remote sensing, together with supporting early career scientists. As such we have a number of students and scientists working with us during the year, and we always like them to write a blog. Something they’re not always keen on at the start! This year we’ve had pieces on:

Writing a blog each week can be hard work, as Wednesday mornings always seem to come around very quickly. However, we think this work adds value to our business and makes a small contribution to explaining the industry in which we work.

Thanks for reading this year, and we hope we can catch your interest again next year.

We’d like to wish everyone a Happy New Year, and a very successful 2017!

Small Satellites Step Forward

Artist's concept of one of the eight Cyclone Global Navigation Satellite System satellites deployed in space above a hurricane. Image courtesy of NASA.

Artist’s concept of one of the eight Cyclone Global Navigation Satellite System satellites deployed in space above a hurricane. Image courtesy of NASA.

We’re all about small satellites with this blog, after looking at the big beast that is GOES-R last week. Small satellites, microsatellites, cubesats or one of the other myriad of names they’re described as, have been in the news this month.

Before looking at what’s happening, we’re going to start with some definitions. Despite multiple terms being used interchangeably, they are different and are defined based around either their cubic size or their wet mass – ‘wet mass’ refers to the weight of the satellite including fuel, whereas dry mass is just the weight of satellite:

  • Small satellites (smallsats), also known as minisats, have a wet mass of between 100 and 500 kg.
  • Microsats generally have a wet mass of between 10 and 100 kg.
  • Nanosats have a wet mass of between 1 and 10 kg.
  • Cubesats are a class of nanosats that have a standard size. One Cubesat measures 10x10x10 cm, known as 1U, and has a wet mass of no more than 1.33 kg. However, it is possible to join multiple cubes together to form a larger single unit.
  • Picosats have a wet mass of between 0.1 and 1 kg
  • Femtosats have a wet mass of between 10 and 100 g

To give a comparison, GOES-R had a wet mass of 5 192 kg, a dry mass of 2 857 kg, and a size of 6.1 m x 5.6 m x 3.9 m.

Small satellites have made headlines for a number of reasons, and the first two came out of a NASA press briefing given by Michael Freilich, Director of NASA’s Earth science division on the 7th November. NASA is due to launch the Cyclone Global Navigation Satellite System (CYGNSS) on 12th December from Cape Canaveral. CYGNSS will be NASA’s first Earth Observation (EO) small satellite constellation. The mission will measure wind speeds over the oceans, which will be used to improve understanding, and forecasting, of hurricanes and storm surges.

The constellation will consist of eight small satellites in low Earth orbits, which will be focussed over the tropics rather than the whole planet. Successive satellites in the constellation will pass over the same area every twelve minutes, enabling an image of wind speed over the entire tropics every few hours.

Each satellite will carry a Delay Doppler Mapping Instrument (DDMI) which will receive signals from existing GPS satellites and the reflection of that same signal from the Earth. The scattered signal from the Earth will measure ocean roughness, from which wind speed can be derived. Each microsatellite will weigh around 29 kg and measure approximately 51 x 64 x 28 cm; on top of this will be solar panels with a span of 1.67 m.

The second interesting announcement as reported by Space News, was that NASA is planning to purchase EO data from other small satellite constellation providers, to assess the quality and usability of that data. They will be one-off purchases with no ongoing commitment, and will sit alongside data from existing NASA missions. However, it is difficult not to assume that a successful and cost effective trial could lead to ongoing purchases, which could replace future NASA missions.

It’s forecast that this initiative could be worth in the region of $25 million, and will surely interest the existing suppliers such as Planet or TerraBella; however, in the longer term it could also attract new players to the market.

Finally in non NASA small satellite news, there was joint announcement at the start of the month by the BRICS states (Brazil, Russia, India, China and South Africa) that they’d agreed to create a joint satellite constellation for EO. No further detail is available at this stage.

Once again, this shows what a vibrant, changing and evolving industry we work in!

Earth observation: Launches Gone, Launches Due & Launches Planned

Artist's rendition of a satellite - 3dsculptor/123RF Stock Photo

Artist’s rendition of a satellite – 3dsculptor/123RF Stock Photo

September is a busy month for Earth observation satellites, and so here is a round-up of the month.

Launches Gone
The Indian Space Research Agency (ISRA) launched the INSAT-3DR weather satellite on September 8th into a geostationary orbit. It carries a multi-spectral imager capable of collecting data in six wavebands: visible, shortwave and midwave infrared, water vapour and two thermal bands. Taking an image every 26 minutes it will be used to monitor cloud patterns and storm systems, collecting data about outgoing longwave radiation, precipitation estimates, Sea Surface Temperature (SST), snow cover and wind speeds.

The second major launch took place on September 15th, from Europe’s Space Centre in French Guiana, when five new Earth observation satellites were put into orbit.

  • Four of these satellites, SkySats 4, 5, 6 & 7, were launched for the commercial company Terra Bella – which is owned by Google. It’s reported that they have informally named these satellites after the Star Wars characters: R2D2, Luke, C3PO and Leia! These small satellites provide 90 cm resolution for panchromatic images and 2 m for visible and near infrared wavebands. They also offer video acquired at 30 frames per second with a resolution of 1.1 m.
  • In addition, this launch brought a new country into the Earth Observation satellite owning family, as Peru launched PeruSAT-1 which will be operated by their military authorities. This satellite is in a 695 km sun-synchronous low Earth orbit and will provide imagery in the visible light wavebands with a 70 cm resolution. The data is expected to help study forest health, monitor illegal logging and gold mining, and provide support with natural disasters. However, the details of who can access to the data, the cost and how to access it are still to be made public.

Launches to Come
Last week we said DigitalGlobe’s WorldView-4 satellite was due to launch on the Friday. The problem of having a blog go live before an event means you can be wrong, and on this occasion we were! Friday’s launch was postponed for two days due to a leak during the propellant loading. Unfortunately, a wildfire then broke out near the Vandenburg Air Force base, and the launch had to be postponed a second time. It is hoped it will go ahead before the end of the month.

Following on from INSAT-3DR, ISRA is due to launch another four satellites in the last week of September including:

  • India’s ScatSat, a replacement for the Oceansat-2. Carrying OSCAT (OceanSat-2 Scanning Scatterometer) it will offer data related to weather forecasting, sea surface winds, cyclone prediction and tracking satellite. The data collected will be used by organisations globally including NASA, NOAA and EUMETSAT.
  • A second Earth observation satellite on the launch is Algeria’s first CubeSat – AlSat Nano. It was designed and built at the Surry Space Centre by Algerian Graduate students, as part of joint programme between the UK Space Agency and the Algerian Space Agency. It will carry a camera, magnetometer and will be testing an innovative solar cell which is one tenth of a millimetre thick.

Launches Being Planned
The next country to join the Earth Observation community could well be North Korea. It was reported this week that they had carried out a successful ground test of a new rocket engine which would give them the capacity to launch various satellites, including Earth Observation ones.

Airbus Defence and Space also announced plans this week for four Earth observation satellites to be launched in 2020 and 2021. These will provide very high resolution imagery and continuity for the existing two Pléiades satellites.

As we’ve previously discussed, the trend in launches continues apace for the Earth observation community.

Earth observation satellites in space in 2016

Blue Marble image of the Earth taken by the crew of Apollo 17 on Dec. 7 1972. Image Credit: NASA

Blue Marble image of the Earth taken by the crew of Apollo 17 on Dec. 7 1972.
Image Credit: NASA

If you’d like the 2017 update, please click here.

Earth Observation (EO) satellites account for just over one quarter of all the operational satellites currently orbiting the Earth. As noted last week there are 1 419 operational satellites, and 374 of these have a main purpose of either EO or Earth Science.

What do Earth observation satellites do?
According to the information within the Union of Concerned Scientists database, the main purpose of the current operational EO satellites are:

  • Optical imaging for 165 satellites
  • Radar imaging for 34 satellites
  • Infrared imaging for 7 satellites
  • Meteorology for 37 satellites
  • Earth Science for 53 satellites
  • Electronic Intelligence for 47 satellites
  • 6 satellites with other purposes; and
  • 25 satellites simply list EO as their purpose

Who Controls Earth observation satellites?
There are 34 countries listed as being the main controllers of EO satellites, although there are also a number of joint and multinational satellites – such as those controlled by the European Space Agency (ESA). The USA is the leading country, singularly controlling one third of all EO satellites – plus they are joint controllers in others. Of course, the data from some of these satellites are widely shared across the world, such as Landsat, MODIS and SMAP (Soil Moisture Active Passive) missions.

The USA is followed by China with about 20%, and Japan and Russia come next with around 5% each. The UK is only listed as controller on 4 satellites all related to the DMC constellation, although we are also involved in the ESA satellites.

Who uses the EO satellites?
Of the 374 operational EO satellites, the main users are:

  • Government users with 164 satellites (44%)
  • Military users with 112 satellites (30%)
  • Commercial users with 80 satellites (21%)
  • Civil users with 18 satellites (5%)

It should be noted that some of these satellites do have multiple users.

Height and Orbits of Earth observation satellites
In terms of operational EO satellite altitudes:

  • 88% are in a Low Earth Orbit, which generally refers to altitudes of between 160 and 2 000 kilometres (99 and 1 200 miles)
  • 10% are in a geostationary circular orbit at around 35 5000 kilometres (22 200 miles)
  • The remaining 2% are described as having an elliptical orbit.

In terms of the types of orbits:

  • 218 are in a sun-synchronous orbit
  • 84 in non-polar inclined orbit
  • 16 in a polar orbit
  • 17 in other orbits including elliptical, equatorial and molniya orbit; and finally
  • 39 do not have an orbit recorded.

What next?

Our first blog of 2016 noted that this was going to be an exciting year for EO, and it is proving to be the case. We’ve already seen the launches of Sentinel-1B, Sentinel-3A, Jason-3, GaoFen3 carrying a SAR instrument and further CubeSat’s as part of Planet’s Flock imaging constellation.

The rest of the year looks equally exciting with planned launches for Sentinel-2B, Japan’s Himawari 9, India’s INsat-3DR, DigitalGlobe’s Worldview 4 and NOAA’s Geostationary Operational Environmental Satellite R-Series Program (GOES-R). We can’t wait to see all of this data in action!