No Paraskevidekatriaphobia For Sentinel-5P!

Sentinel-5P carries the state-of-the-art Tropomi instrument. Image courtesy of ESA/ATG medialab.

On Friday the latest of the Sentinel satellites, Sentinel-5P, is due to be launched at 09.27 GMT from Plesetsk Cosmodrome in Russia.

Friday is the 13th October, and within parts of the western world this is considered to be an unlucky date – although in Italy its Friday 17th which is unlucky and in some Spanish speaking countries it is Tuesday the 13th. Fear of Friday 13th is known as paraskevidekatriaphobia, although evidently it isn’t something Sentinel-5P worries about!

Sentinel-5 Precursor, to give the full title, is dedicated to monitoring our atmosphere. It will create maps of the various trace gases such as nitrogen dioxide, ozone, formaldehyde, sulphur dioxide, methane and carbon monoxide alongside aerosols in our atmosphere. The mission will also support the monitoring of air pollution over cities, volcanic ash, stratospheric ozone and surface UV radiation.

An internal view of the Copernicus Sentinel-5P satellite. Image courtesy of ESA/ATG medialab.

The satellite itself is a hexagonal structure as can be seen in the image to the right. It has three solar wings which will be deployed once the polar sun-synchronous 824 km low earth orbit has been achieved. Sentinel-5P will be orbiting three and half minutes behind NOAA’s Suomi-NPP satellite which carries the Visible/Infrared Imager and Radiometer Suite (VIIRS). This synergy will allow the high resolution cloud mask from VIIRS to be used within the calculations for methane from Sentinel-5P.

Within the hexagonal body the main scientific instrument is the Tropospheric Monitoring Instrument (Tropomi). This is a push-broom imaging spectrometer covering a spectral range from ultraviolet and visible (270–495 nm), near infrared (675–775 nm) and shortwave infrared (2305–2385 nm). The spatial resolution of the instrument will be 7 km x 3.5 km. However, one of the exciting elements of this instrument is that it will have a swath width of 2600 km meaning it can map almost the entire planet every day. It will have full daily surface coverage of radiance and reflectance measurements for latitudes > 7° and < -7°, and better than 95 % coverage for other latitudes.

The key role of Sentinel-5P is to reduce the data gap between the end of the Envisat mission in May 2012 and the launch of Sentinel-5 in 2020. Sentinel-5, and Sentinel-4, will be instruments onboard meteorological satellites operated by Eumetsat and both will be used to monitor the atmosphere.

The timing of Sentinel-5 is interesting for those of within the UK given that almost three quarters of the funding from Copernicus comes from the European Union. By this time Brexit will have occurred and it is currently unclear how that will impact on our future involvement in this programme. This also applies to the work announced at the end of last month to look at an expansion of the Sentinel missions. Invitations to tender (ITT) are due to be issued in the near future, and given our previous blogs on potential limitations and issues, it will be interesting to see which UK companies bid, and whether they will be successful.

Sentinel-5P will help improve our understanding of the processes within the atmosphere which affect our climate, the air we breathe and ultimately the health of everyone on the planet.

World Record Satellite Launch

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

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

Next week the Indian Space Research Organisation (ISRO) plans to launch 104 satellites in one go aboard its Polar Satellite Launch Vehicle (PSLV-C37) that will take off from Satish Dhawan Space Centre in Sriharikota, India.

To give an idea of the enormity of what ISRO is attempting, the current world record for satellites launched in a single mission is 37 by Russia in 2014. In addition, over the last fifty years the average number of objects launched in space in an entire year is only 138, according to the Online Index of Objects Launched into Outer Space maintained by the United Nations Office for Outer Space Affairs (UNOOSA). Furthermore these figures reveal this single mission will exceed the number of objects launched into space for the twelve months of 1996 and for the years 2001 to 2006 inclusive.

This mission was originally planned to launch 83 satellites, then an additional 20 were added to the payload and finally a further nano-satellite was squeezed in. Of these 104 satellites, 3 will be Indian satellites and the remainder will be small satellites from countries including Germany, Israel, Kazakhstan, Netherlands, Switzerland, and the US.

One of the key challenges is to ensure that they do not collide. ISRO plans to achieve this by changing the degree of angle for each batch of satellites launched. It is expected that the entire batch of satellites will be launched within 90 minutes.

This launch is a really exciting one for the Earth Observation community because it includes:

  • Cartosat 2D is the next satellite in India’s Cartosat mission. These satellites carry both high resolution multi- spectral imagers and a panchromatic camera, and the mission focus is cartography. It has a sub-metre spatial resolution, a 10 km swath and a revisit period of four days. This is the primary payload, and will be the heaviest satellite on the launch vehicle at 730 kg.
  • Planet’s Flock 3p which consists of 88 satellites, and will be the largest constellation of satellites ever launched.

Planet was in the news last week as it confirmed it had completed the purchase of satellite imaging company Terra Bella from Google. Terra Bella’s SkySat’s fleet of high resolution satellites will complement the existing global coverage of Planet’s existing courser resolution fleet. When combined with the new satellites, this will help Planet to achieve their aim of imaging the entire globe every day. Thereby, offering a wide range of potential capabilities for Planet in the satellite data reseller/supplier market.

ISRO’s launch is currently scheduled for February 15th and will demonstrate a new level of efficiency for cubesats; something that is becoming increasingly important. We’ll be watching closely, and wish them luck.