Soyuz delivers Sentinel-1B
After three on-pad scrubs, a Soyuz rocket successfully launched Europe's Sentinel-1B remote-sensing satellite on April 25, 2016, along with four secondary payloads: the French Space Agency's Microscope satellite and a trio of educational CubeSats for ESA. In the nomenclature of the Arianespace company, which managed the launch, the mission was known as VS14, denoting the 14th launch of the Soyuz rocket from its facility in Kourou, French Guiana. The launch was actually the 6th mission for the Soyuz family of rockets in 2016, but also the first originating from Kourou that year.
Soyuz VS14 mission at a glance:
Three launch delays
The launch of the Soyuz-ST-A booster with a Fregat-M upper stage was originally scheduled for April 22, 2016, at 6:02:13 p.m. local time from the Soyuz launch facility in Kourou, French Guiana. However on the day of the launch, despite full readiness of hardware and facilities for the mission, the liftoff had to be postponed for at least 24 hours due to high winds. According to the announcement from Arianespace issued on the day of the launch, given the weather conditions observed above the Guiana Space Center - and the forecast for the moment of liftoff - Arianespace decided to interrupt the final countdown and not initiate launcher fueling operations.
Around the same time, the favorable weather forecast for the next day enabled the mission officials to schedule the next launch attempt 24 hours later, on April 23, 2016, at 6:02:13 p.m. local time (21:02 UTC, 5:02 p.m. EDT). However, on April 23, yet again, despite seemingly improved weather, high winds in the upper atmosphere forced another 24-hour delay.
On April 24, the weather was good and the countdown proceeded smoothly until around 45 minutes before the scheduled liftoff, when Arianespace reported a problem with the SYZ Inertial Measurement Unit on the launch vehicle. The system as known in Russian as KKP -- a Russian for Command Instruments Complex. Officials could not immediately confirm whether another launch attempt would be possible in 24 hours. However around three hours later, Arianespace announced that the new launch attempt would be made on April 25, 2016, at 6:02:13 p.m. local time (5:02 p.m. EDT, 21:02 GMT). Replacement operations were underway for the inertial unit that was affected by an outage, Arianespace said.
On the morning of April 25, ESA announced that activities had been still underway in Kourou to replace the inertial unit. The result of a new technical review was expected around 11:30 GMT (7:30 a.m. EDT), the agency said. Early afternoon GMT, ESA announced that the technical anomaly had been resolved, the weather had been cooperative and, therefore, preparations for the launch had resumed.
This time, everything went by the book and the Soyuz-ST-A rocket lifted off on April 25, 2016, at 6:02:13 p.m. local time (21:02 UTC, 5:02 p.m. EDT).
The Soyuz rocket with Sentinel-1B on the launch pad on April 24, 2016.
Sentinel-1B delivered successfully!
During the mission, the vehicle carried the Sentinel-1B satellite heading to a Sun-synchronous orbit extending from pole to pole.
After several seconds of vertical ascent, the rocket headed north over the Atlantic Ocean. Four strap-on boosters of the first stage finished firing and separated one minute 58 seconds in flight. The payload fairing then split into two halves and separated three minutes 29 seconds into the flight.
The second stage completed its firing and separated four minutes 48 seconds into the flight. Moments earlier, the main engine of the third stage ignited and fired for four minutes until eight minutes 49 seconds into the flight.
Immediately, the Fregat-M upper stage with its five payloads separated and after a minute-long ballistic flight, it fired its main engine for the first time. The maneuver lasted 10 minutes and 25 seconds placing the stack into a 686-kilometer orbit 20 minutes 14 seconds after liftoff. After three minutes and 21 seconds in passive flight, the Sentinel-1B satellite separated from the ASAP-S adapter on the Fregat, completing the primary goal of the mission just 23 minutes and 35 seconds after leaving Earth.
Following the release of Sentinel-1B, the Fregat and four of its payloads made a nearly full revolution around the Earth in the unpowered flight lasting almost an hour and a half. Two hours and five seconds into the mission, the Fregat fired its engine again, this time against the direction of the flight and lasting just 13 seconds. The maneuver reduced the orbital perigee forming a 453 by 665-kilometer elliptical (egg-shape) orbit. Slightly more than 48 minutes later, a trio of tiny CubeSats satellites was released from their common P-Pod container. Another 50 seconds later, the ASAP-S structure, which previously held the Sentinel-1B satellite also separated, revealing the Microscope satellite below it.
Fregat's third maneuver began three hours 32 minutes and 35 seconds after launch. The 12-second burn raised the apogee once again and after a 25-minute passive flight, it concluded with another 16-second maneuver to form the prescribed 711-kilometer circular orbit for the release of the Microscope satellite. The separation took place four hours 52 seconds into the flight, completing the payload deliveries during the mission.
Still 15 minutes later, the Fregat was programmed to perform its 5th and final braking engine burn lasting 29 seconds to complete the mission. The stage was expected to burn up in the Earth's atmosphere to reduce the amount of space junk. If any debris survived the fiery plunge, it would fall into a remote section of the ocean.
VS14 mission profile (Phase 1):
VS14 mission profile (Phase 2):
VS14 mission timeline:
The 2,164-kilogram Sentinel-1B is the second satellite in a series of spacecraft carrying all-weather, day-and-night imaging system, known as Synthetic Aperture Radar, or SAR. The satellite is launched by Arianespace under a contract from the European Space Agency and on the behalf of the European Commission, EC.
In turn, the two-satellite Sentinel-1 series is a part of a wider Copernicus project funded jointly by the EC and ESA. The project was previously known as Global Monitoring for Environment and Security or GMES.
The first satellite in the constellation, Sentinel-1A, was launched in April 2014. Sentinel-2, launched on June 23, 2015, was designed to deliver high-resolution optical images for land services. Sentinel-3a ocean-watching satellite was launched earlier in 2016. Sentinel-4 and -5 will provide data for atmospheric composition monitoring from geostationary and polar orbits, respectively. Sentinel-6 will carry a radar altimeter to measure global sea-surface height, primarily for operational oceanography and for climate studies. In addition, a Sentinel-5 Precursor mission is being developed to reduce a time gap in data availability between the operation of the current Envisat satellite, and in particular its Sciamachy instrument, and the launch of new-generation Sentinel-5.
The entire Copernicus constellation was designed to fulfill wide-ranging applications from environmental research to monitoring climate change and managing emergency situations. ESA called Copernicus the largest and most ambitious (space-based) environment-monitoring program in the world.
Within the Copernicus program, the EC, acting on behalf of the European Union, is responsible for the overall initiative, setting requirements and managing the services.
On its end, ESA manages all Sentinel satellites and serves users with satellite data available through the Sentinels and the Copernicus Contributing Missions at national, European and international levels.
Sentinel-1B was built by the Thales Alenia Space Italy on the basis of its PRIMA platform, which stands for Piattaforma Italiana Multi-Applicativa.
The main and only payload onboard the satellite is a C-band SAR radar. Working in tandem, a pair of Sentinel-1A and 1B satellites will be able to revisit and observe any point on Earth in less than six days. To achieve this revisit frequency, the two satellites will be inserted into orbit on opposite sides of the Earth, 180 degrees apart.
The satellites of this type are used for a variety of practical applications and for scientific research, such as monitoring of sea ice, icebergs, icecaps, waves, wind and currents, as well as detection of oil pollution. Over land, Sentinel-1 can contribute to agriculture, forestry and hydrology. These satellites are also capable of highly accurate detection of ground movement for applications related to subsidence, volcano monitoring, the analysis of earthquakes and other uses. Last but not least, Sentinel-1 could also support the management of emergency situations, such as flooding.
Imaging data from Sentinel-1's radar can be downlinked to ground stations in Svalbard, Norway; Matera, Italy; Maspalomas, Spain; and Inuvik, Canada. When the satellite is out of direct view of ground stations, images could still be sent to the ground in many cases by a special laser channel routed via Europe's EDRS data-relay satellite in the geostationary orbit.
A Sentinel-1B satellite in orbit.
Known specifications of the Sentinel-1B satellite:
Sentinel-1B SAR radar operational modes:
Along with the Sentinel-1B, four hitchhiker satellites will be joining the VS14 mission, bringing a total payload mass during the launch to 3,099 kilograms. They include the Microscope satellite for the French Space Agency, CNES, and three CubeSats for the Fly Your Satellite! program conducted by the Education and Knowledge Management Office of the European Space Agency, ESA.
During the launch, Cubesat-launching container will be attached to the two-payload adapter structure built by RUAG space and mounted on the Fregat. In turn, the RUAG's adapter will hold the barrel-shaped Auxiliary Payload Adapter Structure for Soyuz, or ASAP-S for short, which will interface with the Sentinel-1B satellite above it, while also covering the Microscope satellite inside it.
There was also a plan to launch the Norwegian Norsat-1 micro-satellite during the mission, but it had to be canceled due to a technical problem apparently discovered just weeks before launch. According to the Norwegian Space Center, both the satellite and XPOD were ready for launch, but the bracket provided by Arianespace was not properly designed. "It was concluded that it is unsafe to proceed with the launch with the current bracket structure," the center announced on April 14, 2016, "At present, the Norwegian Space Center is working with Arianespace and others to find suitable launch opportunities as soon as possible, with a target of later this year."
The Microscope satellite
The artist rendering of the Microscope satellite
The 303-kilogram Microscope satellite was under development since 2004 by the French Space Agency, CNES, based on its Myriade platform and in cooperation with ESA, the German space agency, DLR, and the European aerospace industry. According to its official description, Microscope satellite (Micro-Satellite à traînée Compensée pour l’Observation du Principe d’Equivalence) will test the equivalence principle described by Albert Einstein, with an unprecedented accuracy on the order of 10(-15). In space, it is possible to study the relative motion of two bodies in almost perfect and permanent free fall aboard an orbiting satellite, shielded from perturbations encountered on Earth (notably seismic), over the course of several months.
To achieve this, the T-SAGE instrument onboard the Microscope will carry two concentric cylindrical test masses made of different materials – one titanium and one a platinum-rhodium alloy, which will be minutely controlled to keep them motionless with respect to the satellite inside independent differential electrostatic accelerometers. If the equivalence principle is verified, the two masses will be subjected to the same control acceleration. If different accelerations have to be applied, the principle will be violated: an event that would shake the foundations of physics.
The Microscope should be delivered into a 711-kilometer near-polar orbit with an inclination 98.23 degrees toward the Equator. The satellite will be able to use its cold-gas micro-thrusters to compensate for the smallest trajectory perturbations that might otherwise skew its results, CNES said.
The satellite is expected to operate for up to three years, after which, it is designed to deploy 4.5-meter booms, which will increase the atmospheric drag, accelerating the decay of its orbit.
CNES provided 90 percent of the funding for the Microscope satellite, its operation and for its mission control.
Known specifications of the Microscope satellite:
CubeSats for the Fly Your Satellite! project
Three student-built CubeSats with a mass of just a kilogram each will accompany Sentinel-1B and Microscope during a ride to orbit:
The satellites are planned for release from a P-POD container into a 453 by 665-kilometer elliptical orbit, where they can operate for around a year.
The three payloads have been selected out of six teams participating in the Fly Your Satellite! educational program, which was developed by ESA in collaboration with European universities and aimed at complementing the traditional academic education.
The project gave university students across Europe a unique opportunity to gain practical experience in developing a small satellite, known as CubeSat, including its integration, tests and launch. According to the agency, the project aimed to inspire, engage and better prepare students to undertake scientific and technological careers, particularly in the space sector. Fly Your Satellite! is part of the newly-established ESA Education and Knowledge Management Office’s program.
Known specifications of the Fly Your Satellite! CubeSats:
Arianespace company announced the agreement for the launch of the Sentinel-1B satellite on July 17, 2014. The launch campaign began in Kourou on March 1, 2016, with the processing of the Fregat-M upper stage at the Soyuz processing complex. The Sentinel-1B satellite arrived to Kourou on March 8 and was sent to the S5B building for processing. The Microscope satellite followed two days later and three CubeSats arrived on March 25.
On March 21, the Fregat was brought to FCube building for fueling, which continued until April 11. In the meantime, the first and second stages of the Soyuz rocket were assembled from March 21 to April 1, 2016, followed by pneumatic and electrical checks on all three stages until April 15.
On March 31, Sentinel-1B was moved from S5B to S3B facility and on April 5, all CubeSats were attached to the ASAP-S launch adapter. The next day, the Sentinel-1B underwent fueling, while the Microscope was added to the ASAP-S structure.
On April 8, ASAP-S and its payloads moved from S5 to S3B facility and a day later the third stage of the Soyuz rocket was integrated in the vehicle assembly building.
On April 12, the Fregat arrived to the S3B building as well, and a day later, the ASAP-S structure was mounted on the stage. The payload section was completed with the installation of the Sentinel-1B on top of ASAP-S on April 14. A day later, the payload section was covered with its fairing.
Final preparations of the launch vehicle and the upper composite began on April 18 and the next day, both were delivered to the launch pad. The upper composite was lifted and installed on top of the rocket. Final checks were conducted on April 20, followed by preparations for fueling of the rocket, the rehearsal of launch procedures and the launch readiness review, RAL, on April 21.
Sentinel-1B fails in orbit
Sentinel-1B experienced problems with its power-supply system on Dec. 23, 2021, and, after a series of unsuccessful troubleshooting attempts, ESA announced ending the satellite's mission in August 2022. The satellite was scheduled to be deorbited in 2023.
Payload configuration during the VS14 mission. Credit: Arianespace
Launch of the Sentinel-1B satellite during the operation of the second stage. Click to enlarge. Credit: ESA
Click to enlarge. Credit: ESA
Artist rendering showing fairing separation during the launch of Sentinel-1B. Click to enlarge. Credit: ESA
Artist rendering showing separation of the third stage from the Fregat during the launch of Sentinel-1B. Click to enlarge. Credit: ESA
Artist rendering showing separation of the Sentinel-1B satellite from Fregat upper stage. Click to enlarge. Credit: ESA
Once safely in the airlock at Europe’s Spaceport in French Guiana after its journey from Thales Alenia Space in Cannes, France, the team opened the transport container to check on Sentinel-1B. It was then moved to the ‘high bay’ for testing. Click to enlarge. Credit: ESA
The payload section for the VS14 mission. Click to enlarge. Credit: CNES, ESA, Arianespace
Secondary payloads of the VS14 mission: a P-POD container with a trio of CubeSats attached to the edge of the ASAP-S adapter and the Microscope satellite behind a circular window of the payload adapter. Click to enlarge. Credit: ESA
The installation of the protective fairing around the payload section of the VS14 mission. Click to enlarge. Credit: CNES, ESA, Arianespace
The Soyuz VS14 upper composite hoisted to the top of the service tower in preparation for the launch of Sentinel-1B on 22 April 2016. Click to enlarge. Credit: CNES, ESA, Arianespace
Soyuz VS14 upper composite hoisted to the top of the service tower on April 20, 2016. Click to enlarge. Credit: CNES, ESA, Arianespace
The Soyuz rocket for the VS14 mission rolls out of the assembly building on April 20, 2016. Click to enlarge. Credit: ESA
The Soyuz rocket for the VS14 mission shortly after arrival at the launch pad on April 20, 2016. Click to enlarge. Credit: ESA
Pre-launch assembly of the Microscope satellite. Credit: CNES
T-SAGE instrument for the Microscope satellite. Click to enlarge. Credit: CNES
The Fly Your satellite! team poses with their three CubeSats and their launch container at the start of the integration process in March 2016. Click to enlarge. Credit: ESA
The P-POD deployment container with three CubeSats installed on the Soyuz’s ASAP-S payload platform. Click to enlarge. Credit: ESA
Soyuz-ST-A lifts off from Kourou with Sentinel-1B on April 25, 2016. Click to enlarge. Credit: ESA