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ARCHIVIERTER INHALT
06 JUL. 2023
Veröffentlichungsdatum
12542
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When the RIME antenna on ESA’s Juice mission failed to deploy a few days after launch, the engineering teams faced the mighty challenge to understand the fault and rectify it. At stake was a chance to see inside Jupiter’s mysterious icy moons.
The stakes were already high before the spacecraft ever left the ground. ESA’s Jupiter Icy Moons Explorer (Juice) was designed by Airbus to conduct an unprecedented investigation of the Jupiter system and its family of icy moons.
A key to that investigation is the Radar for Icy Moon Exploration (RIME) antenna, which is part of Juice's comprehensive suite of ten science instruments. Once in the Jupiter system, RIME will be used to remotely probe the subsurface of Jupiter’s icy moons. Its radar signals will penetrate the moons to a depth of 9 km, and reveal details of between 50 and 140 m across. This will give insight into their geology and provide unique data to understand the habitability of these remote, icy moons.
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Juice’s RIME antenna, folded up ready for deployment
Satisfied, the team moved on to the second segment.
The command was given to fire the actuator. The telemetry arrived before the images, but something was wrong. The expected oscillation was not showing. A few seconds later, the camera image came back. The boom segment was still clearly visible in its stowed configuration. The deployment had failed.
“You experience a state of disbelief,” says Ronan, “The most unwanted situation is happening. We checked the picture two, three, four times. We tried again to activate the actuator, but nothing happened.”
Also watching in a state of professional disbelief were the team at Airbus Defence and Space, Toulouse, France. Chosen as the spacecraft’s prime contractor in 2015, they were responsible for leading the design, construction and testing of the spacecraft and bringing in other companies to supply components, systems and instruments as needed.
“We knew that we had to quickly try to understand what had happened, and then try to find a workaround,” says Frédéric Faye, Airbus’s chief engineer for Juice.
The very next morning, with the disbelief banished from their minds, the teams gathered online for a teleconference to share their insights and discuss the anomaly. On one hand, they knew they had to find some way to free the stuck segment, but on the other they knew that they could not do anything that would compromise the deployment of the other segments, or indeed the rest of the spacecraft.
The first thought that occurred to the teams was that perhaps some ice had formed on the pin holding the segment in place. Every time a spacecraft leaves Earth, it finds itself in a cold, airless environment. This sudden and dramatic loss of air pressure means that a small amount of water vapour will suddenly escape from the material used to make the craft. This can then freeze onto the incredibly cold surfaces of the spacecraft.
Since there are no heaters on the spacecraft near RIME, removing the ice would mean rotating the spacecraft so that the antenna faced the Sun. But, the surface of the spacecraft holding RIME was designed to be a ‘cold face’, meaning that it was never intended to be exposed to the direct sunlight just after launch. Nor were the components, instruments and systems that were attached to it.
After several days of study, the team began gradually slewing the spacecraft so that the surface was illuminated. “We did eight slews over two weeks to illuminate the RIME bracket,” says Angela Dietz, Spacecraft Operations Manager at ESOC. Each time they exposed the surface for longer, carefully watching the telemetry from the onboard sensors to understand the limits of this operation. At first, the manoeuvre lasted just 25 minutes. By the end, they felt comfortable exposing the surface for 73 minutes at a time.
Simultaneously, other possible recovery scenarios were being contemplated.
If it were not ice holding RIME shut, and the pin had simply stuck, then perhaps shaking the spacecraft would jog it loose – although the word ‘shaking’ is too extreme to describe the actual motion.
The spacecraft weighs six tonnes and the thrusters onboard can only rock it back and forth very gently. Nevertheless, the teams felt it was worth trying. The stuck pin probably only needed moving by a millimetre or two, but the teams had to be careful. They could not risk harming anything else with a violent jolt of the spacecraft. So, as the team had done with the heating, they began testing this manoeuvre cautiously.
And that’s where the problems began.
Ronan Le Letty, Senior Mechanisms Engineer for ESA and part of the Juice team, was at ESOC during the RIME deployment, advising the flight control team who were receiving telemetry from the spacecraft’s various onboard sensors and sending Juice commands.
The procedure began on 17 April 2023, three days after the launch and with everything having proceeded smoothly up until that point.
Continuing this trend, the first step went without a hitch. Two monitoring cameras, mounted onboard the spacecraft, were used to follow the RIME deployment. From the downloads, the antenna segment was visible on one image, and then not on the next. In between the images, the NEA had fired, the pin had released and the antenna segment had snapped into place. A check of the external camera’s image showed the segment in place, and the telemetry data also confirmed this. It showed that the spacecraft was oscillating as expected from the sudden deployment of the boom, and that the Attitude and Orbit Control System (AOCS) was correcting for the last of these movements.
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Successful deployment of the first antenna segment between 12:26 and 13:30
Satisfied, the team moved on to the second segment.
The command was given to fire the actuator. The telemetry arrived before the images, but something was wrong. The expected oscillation was not showing. A few seconds later, the camera image came back. The boom segment was still clearly visible in its stowed configuration. The deployment had failed.
“You experience a state of disbelief,” says Ronan, “The most unwanted situation is happening. We checked the picture two, three, four times. We tried again to activate the actuator, but nothing happened.”
Also watching in a state of professional disbelief were the team at Airbus Defence and Space, Toulouse, France. Chosen as the spacecraft’s prime contractor in 2015, they were responsible for leading the design, construction and testing of the spacecraft and bringing in other companies to supply components, systems and instruments as needed.
“We knew that we had to quickly try to understand what had happened, and then try to find a workaround,” says Frédéric Faye, Airbus’s chief engineer for Juice.
The very next morning, with the disbelief banished from their minds, the teams gathered online for a teleconference to share their insights and discuss the anomaly. On one hand, they knew they had to find some way to free the stuck segment, but on the other they knew that they could not do anything that would compromise the deployment of the other segments, or indeed the rest of the spacecraft.
The first thought that occurred to the teams was that perhaps some ice had formed on the pin holding the segment in place. Every time a spacecraft leaves Earth, it finds itself in a cold, airless environment. This sudden and dramatic loss of air pressure means that a small amount of water vapour will suddenly escape from the material used to make the craft. This can then freeze onto the incredibly cold surfaces of the spacecraft.
Since there are no heaters on the spacecraft near RIME, removing the ice would mean rotating the spacecraft so that the antenna faced the Sun. But, the surface of the spacecraft holding RIME was designed to be a ‘cold face’, meaning that it was never intended to be exposed to the direct sunlight just after launch. Nor were the components, instruments and systems that were attached to it.
After several days of study, the team began gradually slewing the spacecraft so that the surface was illuminated. “We did eight slews over two weeks to illuminate the RIME bracket,” says Angela Dietz, Spacecraft Operations Manager at ESOC. Each time they exposed the surface for longer, carefully watching the telemetry from the onboard sensors to understand the limits of this operation. At first, the manoeuvre lasted just 25 minutes. By the end, they felt comfortable exposing the surface for 73 minutes at a time.
Simultaneously, other possible recovery scenarios were being contemplated.
If it were not ice holding RIME shut, and the pin had simply stuck, then perhaps shaking the spacecraft would jog it loose – although the word ‘shaking’ is too extreme to describe the actual motion.
The spacecraft weighs six tonnes and the thrusters onboard can only rock it back and forth very gently. Nevertheless, the teams felt it was worth trying. The stuck pin probably only needed moving by a millimetre or two, but the teams had to be careful. They could not risk harming anything else with a violent jolt of the spacecraft. So, as the team had done with the heating, they began testing this manoeuvre cautiously.
Medien-Modal
Juice’s stuck but wriggling RIME antenna
Satisfied, the team moved on to the second segment.
The command was given to fire the actuator. The telemetry arrived before the images, but something was wrong. The expected oscillation was not showing. A few seconds later, the camera image came back. The boom segment was still clearly visible in its stowed configuration. The deployment had failed.
“You experience a state of disbelief,” says Ronan, “The most unwanted situation is happening. We checked the picture two, three, four times. We tried again to activate the actuator, but nothing happened.”
Also watching in a state of professional disbelief were the team at Airbus Defence and Space, Toulouse, France. Chosen as the spacecraft’s prime contractor in 2015, they were responsible for leading the design, construction and testing of the spacecraft and bringing in other companies to supply components, systems and instruments as needed.
“We knew that we had to quickly try to understand what had happened, and then try to find a workaround,” says Frédéric Faye, Airbus’s chief engineer for Juice.
The very next morning, with the disbelief banished from their minds, the teams gathered online for a teleconference to share their insights and discuss the anomaly. On one hand, they knew they had to find some way to free the stuck segment, but on the other they knew that they could not do anything that would compromise the deployment of the other segments, or indeed the rest of the spacecraft.
The first thought that occurred to the teams was that perhaps some ice had formed on the pin holding the segment in place. Every time a spacecraft leaves Earth, it finds itself in a cold, airless environment. This sudden and dramatic loss of air pressure means that a small amount of water vapour will suddenly escape from the material used to make the craft. This can then freeze onto the incredibly cold surfaces of the spacecraft.
Since there are no heaters on the spacecraft near RIME, removing the ice would mean rotating the spacecraft so that the antenna faced the Sun. But, the surface of the spacecraft holding RIME was designed to be a ‘cold face’, meaning that it was never intended to be exposed to the direct sunlight just after launch. Nor were the components, instruments and systems that were attached to it.
After several days of study, the team began gradually slewing the spacecraft so that the surface was illuminated. “We did eight slews over two weeks to illuminate the RIME bracket,” says Angela Dietz, Spacecraft Operations Manager at ESOC. Each time they exposed the surface for longer, carefully watching the telemetry from the onboard sensors to understand the limits of this operation. At first, the manoeuvre lasted just 25 minutes. By the end, they felt comfortable exposing the surface for 73 minutes at a time.
Simultaneously, other possible recovery scenarios were being contemplated.
If it were not ice holding RIME shut, and the pin had simply stuck, then perhaps shaking the spacecraft would jog it loose – although the word ‘shaking’ is too extreme to describe the actual motion.
The spacecraft weighs six tonnes and the thrusters onboard can only rock it back and forth very gently. Nevertheless, the teams felt it was worth trying. The stuck pin probably only needed moving by a millimetre or two, but the teams had to be careful. They could not risk harming anything else with a violent jolt of the spacecraft. So, as the team had done with the heating, they began testing this manoeuvre cautiously.
Medien-Modal
The stuck part of the antenna finally deploys
Satisfied, the team moved on to the second segment.
The command was given to fire the actuator. The telemetry arrived before the images, but something was wrong. The expected oscillation was not showing. A few seconds later, the camera image came back. The boom segment was still clearly visible in its stowed configuration. The deployment had failed.
“You experience a state of disbelief,” says Ronan, “The most unwanted situation is happening. We checked the picture two, three, four times. We tried again to activate the actuator, but nothing happened.”
Also watching in a state of professional disbelief were the team at Airbus Defence and Space, Toulouse, France. Chosen as the spacecraft’s prime contractor in 2015, they were responsible for leading the design, construction and testing of the spacecraft and bringing in other companies to supply components, systems and instruments as needed.
“We knew that we had to quickly try to understand what had happened, and then try to find a workaround,” says Frédéric Faye, Airbus’s chief engineer for Juice.
The very next morning, with the disbelief banished from their minds, the teams gathered online for a teleconference to share their insights and discuss the anomaly. On one hand, they knew they had to find some way to free the stuck segment, but on the other they knew that they could not do anything that would compromise the deployment of the other segments, or indeed the rest of the spacecraft.
The first thought that occurred to the teams was that perhaps some ice had formed on the pin holding the segment in place. Every time a spacecraft leaves Earth, it finds itself in a cold, airless environment. This sudden and dramatic loss of air pressure means that a small amount of water vapour will suddenly escape from the material used to make the craft. This can then freeze onto the incredibly cold surfaces of the spacecraft.
Since there are no heaters on the spacecraft near RIME, removing the ice would mean rotating the spacecraft so that the antenna faced the Sun. But, the surface of the spacecraft holding RIME was designed to be a ‘cold face’, meaning that it was never intended to be exposed to the direct sunlight just after launch. Nor were the components, instruments and systems that were attached to it.
After several days of study, the team began gradually slewing the spacecraft so that the surface was illuminated. “We did eight slews over two weeks to illuminate the RIME bracket,” says Angela Dietz, Spacecraft Operations Manager at ESOC. Each time they exposed the surface for longer, carefully watching the telemetry from the onboard sensors to understand the limits of this operation. At first, the manoeuvre lasted just 25 minutes. By the end, they felt comfortable exposing the surface for 73 minutes at a time.
Simultaneously, other possible recovery scenarios were being contemplated.
If it were not ice holding RIME shut, and the pin had simply stuck, then perhaps shaking the spacecraft would jog it loose – although the word ‘shaking’ is too extreme to describe the actual motion.
The spacecraft weighs six tonnes and the thrusters onboard can only rock it back and forth very gently. Nevertheless, the teams felt it was worth trying. The stuck pin probably only needed moving by a millimetre or two, but the teams had to be careful. They could not risk harming anything else with a violent jolt of the spacecraft. So, as the team had done with the heating, they began testing this manoeuvre cautiously.
Medien-Modal
Juice’s RIME antenna fully deploys
Satisfied, the team moved on to the second segment.
The command was given to fire the actuator. The telemetry arrived before the images, but something was wrong. The expected oscillation was not showing. A few seconds later, the camera image came back. The boom segment was still clearly visible in its stowed configuration. The deployment had failed.
“You experience a state of disbelief,” says Ronan, “The most unwanted situation is happening. We checked the picture two, three, four times. We tried again to activate the actuator, but nothing happened.”
Also watching in a state of professional disbelief were the team at Airbus Defence and Space, Toulouse, France. Chosen as the spacecraft’s prime contractor in 2015, they were responsible for leading the design, construction and testing of the spacecraft and bringing in other companies to supply components, systems and instruments as needed.
“We knew that we had to quickly try to understand what had happened, and then try to find a workaround,” says Frédéric Faye, Airbus’s chief engineer for Juice.
The very next morning, with the disbelief banished from their minds, the teams gathered online for a teleconference to share their insights and discuss the anomaly. On one hand, they knew they had to find some way to free the stuck segment, but on the other they knew that they could not do anything that would compromise the deployment of the other segments, or indeed the rest of the spacecraft.
The first thought that occurred to the teams was that perhaps some ice had formed on the pin holding the segment in place. Every time a spacecraft leaves Earth, it finds itself in a cold, airless environment. This sudden and dramatic loss of air pressure means that a small amount of water vapour will suddenly escape from the material used to make the craft. This can then freeze onto the incredibly cold surfaces of the spacecraft.
Since there are no heaters on the spacecraft near RIME, removing the ice would mean rotating the spacecraft so that the antenna faced the Sun. But, the surface of the spacecraft holding RIME was designed to be a ‘cold face’, meaning that it was never intended to be exposed to the direct sunlight just after launch. Nor were the components, instruments and systems that were attached to it.
After several days of study, the team began gradually slewing the spacecraft so that the surface was illuminated. “We did eight slews over two weeks to illuminate the RIME bracket,” says Angela Dietz, Spacecraft Operations Manager at ESOC. Each time they exposed the surface for longer, carefully watching the telemetry from the onboard sensors to understand the limits of this operation. At first, the manoeuvre lasted just 25 minutes. By the end, they felt comfortable exposing the surface for 73 minutes at a time.
Simultaneously, other possible recovery scenarios were being contemplated.
If it were not ice holding RIME shut, and the pin had simply stuck, then perhaps shaking the spacecraft would jog it loose – although the word ‘shaking’ is too extreme to describe the actual motion.
The spacecraft weighs six tonnes and the thrusters onboard can only rock it back and forth very gently. Nevertheless, the teams felt it was worth trying. The stuck pin probably only needed moving by a millimetre or two, but the teams had to be careful. They could not risk harming anything else with a violent jolt of the spacecraft. So, as the team had done with the heating, they began testing this manoeuvre cautiously.
Medien-Modal
Juice mission operators celebrating the successful deployment of another instrument, RPWI
Satisfied, the team moved on to the second segment.
The command was given to fire the actuator. The telemetry arrived before the images, but something was wrong. The expected oscillation was not showing. A few seconds later, the camera image came back. The boom segment was still clearly visible in its stowed configuration. The deployment had failed.
“You experience a state of disbelief,” says Ronan, “The most unwanted situation is happening. We checked the picture two, three, four times. We tried again to activate the actuator, but nothing happened.”
Also watching in a state of professional disbelief were the team at Airbus Defence and Space, Toulouse, France. Chosen as the spacecraft’s prime contractor in 2015, they were responsible for leading the design, construction and testing of the spacecraft and bringing in other companies to supply components, systems and instruments as needed.
“We knew that we had to quickly try to understand what had happened, and then try to find a workaround,” says Frédéric Faye, Airbus’s chief engineer for Juice.
The very next morning, with the disbelief banished from their minds, the teams gathered online for a teleconference to share their insights and discuss the anomaly. On one hand, they knew they had to find some way to free the stuck segment, but on the other they knew that they could not do anything that would compromise the deployment of the other segments, or indeed the rest of the spacecraft.
The first thought that occurred to the teams was that perhaps some ice had formed on the pin holding the segment in place. Every time a spacecraft leaves Earth, it finds itself in a cold, airless environment. This sudden and dramatic loss of air pressure means that a small amount of water vapour will suddenly escape from the material used to make the craft. This can then freeze onto the incredibly cold surfaces of the spacecraft.
Since there are no heaters on the spacecraft near RIME, removing the ice would mean rotating the spacecraft so that the antenna faced the Sun. But, the surface of the spacecraft holding RIME was designed to be a ‘cold face’, meaning that it was never intended to be exposed to the direct sunlight just after launch. Nor were the components, instruments and systems that were attached to it.
After several days of study, the team began gradually slewing the spacecraft so that the surface was illuminated. “We did eight slews over two weeks to illuminate the RIME bracket,” says Angela Dietz, Spacecraft Operations Manager at ESOC. Each time they exposed the surface for longer, carefully watching the telemetry from the onboard sensors to understand the limits of this operation. At first, the manoeuvre lasted just 25 minutes. By the end, they felt comfortable exposing the surface for 73 minutes at a time.
Simultaneously, other possible recovery scenarios were being contemplated.
If it were not ice holding RIME shut, and the pin had simply stuck, then perhaps shaking the spacecraft would jog it loose – although the word ‘shaking’ is too extreme to describe the actual motion.
The spacecraft weighs six tonnes and the thrusters onboard can only rock it back and forth very gently. Nevertheless, the teams felt it was worth trying. The stuck pin probably only needed moving by a millimetre or two, but the teams had to be careful. They could not risk harming anything else with a violent jolt of the spacecraft. So, as the team had done with the heating, they began testing this manoeuvre cautiously.
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ESA Expert Lecture about unfolding Juice's RIME antenna
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