Chinese Satellites Going Up, Chinese Satellite Coming Down

Satellites orbiting the Earth

Artist’s rendition of satellites orbiting the Earth – rottenman/123RF Stock Photo

It’s been a busy weekend for the Chinese space industry! On Saturday the China National Space Administration (CNSA) launched three new high resolution Gaofen-1 optical Earth Observation satellites from the Taiyuan Satellite Launch Centre in the north western Shanxi Province of China.

The three new satellites, called Gaofen-1: 02, 03 and 04 respectively, were launched into  sun-synchronous 645 km orbits at 03:22 GMT on the 31st March. They all carry two high resolution cameras, which are capable of acquiring multispectral data at eight metre spatial resolution, and this improves to around two metre resolution for the panchromatic band.

They are believed to be the next generation of the Gaofen-1 satellite which was originally launched on the 26th April 2013. It also carried the two high resolution cameras, but alongside had a wide field imager which is not included on the latest launches.

Saturday’s satellites will operate as a constellation offering a revisit time of two days, with the orbit repeating itself every fifteen days. However, for the foreseeable future, the constellation will also include the original Gaofen-1 satellite and will provide an impressive one-day revisit time and eleven day global coverage. The data from these satellites will be used for applications such as disaster warning, environmental monitoring, construction, transportation and emergency response.

The contrast to these launches was the re-entry of the Tiangong-1 space lab into Earth’s atmosphere on Monday 2 April at 00:15 GMT. Tiangong-1, which translates as Heavenly Palace 1, was originally launched on 29 September 2011. It had a two year operational lifecycle and has orbited the Earth unmanned for almost five years. During 2017, it was announced that the CNSA no longer had any control over Tiangong-1 and that it would gradually fall back to Earth over the coming eighteen months.

This satellite’s demise has caused a lot of public interest. Due in part to greater interest in space debris, but also due to the size and difficulty of determining exactly where it might fall to Earth!

End of life satellites falling back to Earth isn’t a rare occurrence, on average around one satellite each week enters our atmosphere and over a year this equates to around 100 tonnes of metal. The vast majority of this burns up in the atmosphere and apart from offering an interesting occasional fireball backdrop to the sky, it has no impact. Occasionally some of the debris does fall to Earth although most of this tends to be over water.

The difference here is size and mass. Tiangong-1 was 12 m long with a diameter of 3.3 m and had a launch mass of 8,506 kg – although obviously this will be less now.

Tracking space debris is becoming more and more important, and there were 14 space agencies/organisations, collectively known as the Inter Agency Space Debris Co-ordination Committee, tracking Tiangong-1 including NASA, ESA, European national space agencies, JAXA, ISRO, KARI, Roscosmos and the Chinese CNSA themselves.

Despite all of this effort focussed on Tiangong-1, it was very difficult for this group to forecast what debris might fall to Earth and where it might hit. Even when they confirmed entry, it was suggested that debris could hit somewhere in the South Pacific which is a very vague, and large, area.

Generally, it is being reported that most of the space lab burnt up in the atmosphere. However, despite all the effort placed tracking the object in space, there is no similar arrangement to track any debris that might reach the Earth’s surface and so no-one is sure how much, if anything, actually made it back. It may be the coming days, weeks or even months before we find anything that hit land and we may never know if it did hit the ocean.

This weekend just goes to show that the space industry is constantly changing.

First Light Images

Mosaic image of The Netherlands created using three Sentinel-1 scans in March 2015.
Data Courtesy of Copernicus Sentinel data (2015)/ESA.

Two of the satellites launched on 12th January by the Indian Space Research Organization (ISRO) have released their first images. We wrote about the launch two weeks ago, and wanted to follow up on their initial outputs.

The first is the exciting ICEYE-X1, which is both the world’s first synthetic-aperture radar (SAR) microsatellite and Finland’s first commercial satellite. We currently use Sentinel-1 SAR imagery for some of Pixalytics flooding and water extent mapping products and so are really interested to see what this satellite produces.

One of the key advantages of radar satellites over optical ones is that they can capture images both during day and night, and are not hampered by the presence of clouds.  However, using a different part of the electromagnetic spectrum to optical satellites means that although it is black and white image it’s sometimes easier to distinguish objects within it.

Zoomed in portion of Netherlands mosaic image created using three Sentinel-1 scans in March 2015.
Data Courtesy of Copernicus Sentinel data (2015)/ESA.

For example, the image to the left is a zoomed in portion of Sentinel-1 mosaic of the Netherlands acquired in March 2015 where you can clearly see couple of off-shore windfarms.

Sentinel-1 is a twin satellite constellation and uses a C-Band SAR on board two identical satellites. Over land it captures data in an Interferometric Wide swath mode, which means it takes three scans and then combines them into a single image. Each scan has a width of 250 km and a spatial resolution of 5 m x 20 m, with a six day repeat cycle for an area of land.

In comparison, ICEYE-X1 produced its first image with a spatial resolution of 10 m, and it’s hoped to reduce this down to 3 m. It issued its first image on Monday 15th January, three days after launch, showing part of Alaska, including the Noatak National Preserve, with a ground coverage of approximately 80 km by 40 km. The image can be seen here.

ICEYE-X1 weighs in at under a 100 kg, which is less than a twentieth of Sentinel-1 which weighed in at 2 300kg. This size reduction produces a high reduction in the cost too, with estimates suggesting it only cost ICEYE around a hundredth of the €270 million price of the second Sentinel-1 satellite.

By 2020 ICEYE is hoping to establish a global imaging constellation of six SAT microsatellites that will be able to acquire multiple images of the same location on Earth each day. After this, the company has ambitions of launching 18 SAR-enabled microsatellites to bring reliable high temporal-resolution images which would enable every point on the Earth to be captured eight times a day.

Cartosat-2F also sent its first image on the 15th January. The image, which can be found here, is of the city of Indore, in the Indian state of Madhya Pradesh. The Holkar Stadium is tagged in the centre, a venue which has previously hosted test Cricket. The satellite carries a high resolution multi-spectral imager with 1 m spatial resolution and a swath width of 10 km.

It is the seventh satellite in the Cartosat series which began in 2007, the others are:

  • Cartosat 2 launched on 10th January 2007
  • Cartosat 2A launched on 28th April 2008
  • Cartosat 2B launched on 12th July 2010
  • Cartosat 2C launched on 22nd June 2016
  • Cartosat 2D launched on 15th February 2017
  • Cartosat 2E launched on 23rd June 2017

These two satellites are just at the start of their journey, and it will be interesting to see what amazing images they capture in the future.

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
  • 16 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:

  • 186 large satellites equating to 30.00%
  • 74 small satellites equating to 7.26%
  • 100 microsats equating to 16.13%
  • 215 Nanosats/Cubesats equating to 34.68%
  • The remaining 45 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 19.35% (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
  • 125 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!