The European Space Agency is carefully monitoring the evolution of the coronavirus pandemic and has studied different scenarios for the operations of its fleet of missions in this difficult situation. During the last weeks we have put in place procedures which guarantee the safety of our spacecrafts and their instruments. Under most scenarios we will also be able to continue with science operations and observations. Therefore, minimal impact is expected for the scientific community. Nevertheless our ability to react to Targets of Opportunity / triggered observations may be affected.

INTEGRAL Latest News

 

INTEGRAL scientific operations have temporarily been interrupted

23 June 2020 The INTEGRAL mission operations team found that after a reaction wheel bias (RWB) to offload momentum, the pressure in the tanks had dropped by a few tenth of a bar, which then only slowly recovered. In order to further investigate the behaviour of the INTEGRAL system recovery after a RWB coinciding with propellant system pressure drop, and as a test to check a possible new operational approach delaying RWB momentum dumps and thruster usage, scientific operations have temporarily been interrupted in revolution 2243 (that started on the evening of June 22). Pending on the outcome of the test, the plan is to return to science observations in revolution 2244, starting 25 June. Further tests eventually impacting on science performance may be necessary in the future.

ESA Proposal to SPC for Extensions of mission operations for the period 2021 - 2025

23 June 2020 Find below information on the ESA inputs to the SPC meeting #163, planned for July 7-8, deciding about extensions of mission operations for the period 2021-2025 (2 years confirmation + 3 years extension):

Like all the other science missions in operations, also INTEGRAL had received positive reviews and recommendations on the extended mission science case from the Astronomy Working Group (AWG) and the Space Science Advisory Committee (SSAC) that met the 1st half of June.

In light, however, of the need to resolve broader programmatic and cost issues the ESA Directorate of Science Programme is facing in this and the coming 2 years, the Executive decided to postpone a proposal on the extension of the operations of Cluster, INTEGRAL and Mars Express to the next SPC meeting (#164, planned for November 2020).

INTEGRAL Conference 2020 postponed to 2021

19 June 2020 Due to the COVID-19 pandemic, the INTEGRAL conference 2020 "towards the third decade of X and Gamma ray observations" has been moved to 24-29 May 2021. Venue, title, and other aspects communicated so far are unchanged. For details, see the website: https://indico.ict.inaf.it/event/1001/overview.

INTEGRAL's return to science after the 8th Emergency Safe Attitude Mode

Update 12 June 2020 We are pleased to inform that science operations have been resumed as of today. They still require manual intervention at various steps, but it seems that INTEGRAL will be at 95% observing efficiency. A great achievement, within a month after the anomaly.

In the meantime, work is continuing to automate operations to allow a return to close to full scientific observatory utilisation in the mid term (expected is end July); in parallel, investigations are ongoing to understand and characterise the failure case.

5 June 2020 Emergency Safe Attitude Mode (ESAM, the 8th case since launch) was triggered on 16 May 2020 during thruster firing for a standard Reaction Wheel momentum dump. While in the stable Sun pointing safe mode under redundant thruster attitude control, a significant de-pointing took place, automatically recovered within minutes.

The analysis of safe-mode entry and subsequent de-pointing together with dedicated thruster calibrations of both the standard and redundant Reaction Control Systems (comprising of tanks, fuel pipes and thrusters) showed that INTEGRAL experienced a reduction in pressure (from 5.5 to ~5 bar) in the propellant system; thrusters on both chains are found to be underperforming since then at ~50% level with irregular thrust levels. Under the supervision of an Anomaly Review Board, including experts from ESOC (Flight Control and Flight Dynamics Teams) supported by ESTEC (TEC: Propulsion) and Industry (Airbus & Thales), activities are ongoing to study the possible root cause of the anomaly and characterise the changed behaviour, focusing also on remaining fuel and tank pressurant, avoidance of future ESAM entry, and an operational strategy for the handling of the Reaction Wheel control.

Additionally, high priority is now being given to the return to science operations: as the spacecraft observing mode is operative, the science instruments collecting data in staring mode and thrusters performing (they can do so down to at least 3.5 bar according to specs), re-enabling full science observations including the implementation of Targets of Opportunity is targeted by end July.

A modified strategy for alternative wheel control has already successfully been validated. In the early phase of the return to science from mid June, this approach will be based on manual wheel speed adjustments, performed and monitored manually during working hours, including weekends, with a somewhat reduced observing efficiency (~80% TBC). Planning files will need to be modified, tested and handled by the mission planning software at MOC and SOC, which may require some (modest) modifications. As this innovative strategy is expected to leave observing constraints unchanged, the plan is to resume nominal scheduling of the AO-17 Guest Observer program, as originally foreseen.

The full deployment of this new strategy, including in the end again an automated execution of wheel biases, has been kicked-off and is currently pending on necessary changes in mission planning and control software, databases and procedures, on testing progress, and training of Spacecraft Controllers and on-call teams. Full functionality is thus hoped to be restored by end July.

INTEGRAL recovery from Emergency Safe Attitude Mode (ESAM)

Update 28 May 2020 The Thruster Torque calibration with RCS-A was successfully performed on 25 May, showing similar reaction control thruster performance as RCS-B: all thruster are now confirmed to be working and full redundancy in RCS has been re-established.

All thrusters are showing significantly reduced and less stable performance, a behaviour linked most likely to reduced pressure in the propulsion system; a pressure drop from 5.5 to about 5.0 bar had been experienced during the de-pointing on 17 May. Investigations on the root-cause of the pressure drop are on-going. One (TBC) hypothesis being that nitrogen gas, used as tanks pressurant, might have formed bubbles in the hydrazine fluid propellant system that could have been leaving the propulsion system, interrupting thruster firing and explaining the pressure loss. Thrusters are qualified to continue working at least down to 3.5 bar, albeit with decreasing performance.

Instruments (IBIS, JEM-X, SPI) are observing in staring mode, i.e. without spacecraft slews (OMC in Safe Mode due to the attitude). Targets of Opportunities can currently not be performed. The spacecraft remains in stable attitude under reaction wheel control. Another reaction wheel momentum off-loading is planned to be performed on 29 May.

Further discussions on resuming science operations are on-going, including plannings for a modified wheel speed handling procedure.

Update 25 May 2020 In order to prevent reaction wheel 2 or 4 reaching the maximum wheel speed and to avoid autonomous momentum dumping with unpredictable results, on 22 May at 10:00 UT an adjustment of the INTEGRAL wheel speeds was performed: A series of small wheel speed changes was commanded to approach slowly and step by step the desired wheel speeds, limiting the impacts on the satellite inertia moment such that they could easily be absorbed by the thrusters, even with the currently observed reduced thruster performance.

The operation was entirely successful and the spacecraft behaviour as predicted when planning the operation, giving more than 1 weeks time before the need to adjust the wheels speed again, marking also an important first step in demonstrating that INTEGRAL remains controllable in a predictable way.

Investigations about the root cause of the anomaly are still on-going, including further evaluation of the health and performance of the Reaction Control Subsystem (RCS).

A Thruster Torque calibration with RCS-A will start at 15.00 today.

19 May 2020 On 16 May 2020 at 15:30 UT, during a Reaction Wheel Bias (RWB) and triggered by a Pitch Thruster Impulse Monitoring (1) anomaly, INTEGRAL entered nominally into Emergency Safe Attitude Mode (ESAM), turning the spacecraft into an attitude position allowing optimum Solar array power production (Sunline), and putting the payload into a safe configuration.

At 06:30 UT on 17 May, a number of out-of-limits were noted on the payload units, corresponding to an unscheduled eclipse passage, putting the instruments into 'eclipse mode'. Attitude sensor data showed a significant de-pointing, i.e., INTEGRAL had moved quickly away from the Sunline before re-pointing back to the expected Sun pointing direction under thruster control. The reason for this anomalous behaviour during ESAM is at this time not yet understood.

As the thrusters might be related to the cause of the satellite control anomaly, the pressure to move out of thruster-controlled ESAM mode received highest priority. The spacecraft needed to be placed back into Inertial Pointing and Slew (IPS) mode stable under reaction wheel control. The INTEGRAL Flight-Control and Flight-Dynamics teams managed (working almost completely remotely) to achieve IPS mode during the evening of 17 May. Payload reconfiguration after the unexpected 'eclipse' continued afterwards and the expected configuration was reached later in the night. Thruster behaviour was nominal during this operation. Reaction wheels were spun up to 100 RPM each. As the ESAM exit attitude was unconstrained until 19 May at 04:00 UT, a slew to a different safe attitude position took place that will be unconstrained at least until 24 May, adding additional time to continue investigating the causes and recovery scenarios, before the next required manoeuvre.

Regular Anomaly Report Meetings are taking place to define next actions with high urgency, and actions for investigation, including an inventory of all possible theoretical root causes for the ESAM trigger and de-pointing.

No science operations can be performed for the time being. Further updates will be communicated in due time.

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(1) The Pitch Thruster Impulse Monitoring (PTIM) anomaly detection monitors the change in effective angular momentum on the spacecraft Pitch Axis by accumulating the sum of the on-times of Thrusters T1 & T4 minus the on-times of Thrusters T2 & T3.

18th Announcement of Opportunity (AO-18): Preliminary submission statistics

14 May 2020 The deadline for the submission of proposals for AO-18 open time observations was on 4 May 2020, and all proposals are in the ISOC database. Below are some preliminary statistics on the proposals that have been received.

Total number of proposals
The total number of proposals received is 52. The total observing time requested is about 70 Msec (for all types of observation, i.e., fixed time, normal time, and ToO). Here, 10% of the requested total ToO time has been taken into account. Given that up to about 21 Msec of observing time (for new observing proposals) will be available for the AO-18 observing programme (12 months duration starting on 1 January 2020), this corresponds to an oversubscription in time by a factor of 3.35.

The non-ToO proposals are requesting data rights for 336 sources in total. 14 proposals requested joint time with NuSTAR, Swift and/or XMM-Newton.

Proposals per category
In the following table we give the breakdown of number of proposals as a function of the proposal category. Note that the numbers on requested observing times do include ToO proposals, but it has been assumed here, that a typical ToO proposal requests about 10% of its total observing time as entered into PGT from all the candidate sources included in a ToO proposal.

Scientific Category Number of proposals Requested observing time (Ms)
includes ToO times x 10%
Galactic Astronomy 29 55
Extragalactic Astronomy 12 4
Nucleosynthesis and diffuse
continuum/line emission
11 11
Total 52 70

 

Near the end of June, the Time Allocation Committee will peer review all proposals and recommend the AO-18 observing programme to ESA.

Update: Coronavirus & INTEGRAL Conference

30 April 2020 Due to the known events regarding the COVID-19 situation, the final dates of the INTEGRAL Conference, "INTEGRAL: Towards the third decade of X- and Gamma-ray observations", to be held 5-10 October 2020 in Sardinia, Italy, will be confirmed at the end of May. Apologies for any inconvenience this may cause. Contact the organizers at integral2020 (at) inaf.it for further information.

INTEGRAL AO-18 proposal submission deadline delayed to 4 May 14:00 CEST due to COVID-19, coronavirus

23 March 2020 ESA is doing its best to guarantee that the proposal submission and review processes remain optimal within the restrictions imposed by the COVID-19, coronavirus crisis. Since measures deployed in the ESA’s Member States have disrupted scientific activities in those countries, the INTEGRAL AO-18 proposal submission deadline has been postponed from Friday, 3 April to Monday, 4 May 14:00 CEST.

INTEGRAL AO-18 CALL FOR OBSERVING PROPOSALS IS OPEN!

2 March 2020 Today, the Director of Science (Prof. Guenther Hasinger) has released the 18th Announcement of Opportunity (AO-18) for observing proposals with INTEGRAL.

This announcement solicits proposals for observations to be carried out from January 2021 for a period of 12 months. Proposers from all over the world are welcome to participate. All proposals will be subject to an independent peer review by the INTEGRAL Time Allocation Committee (TAC). The deadline for proposal submission is Friday 3 April 2019, 14:00 CEST.

More information can be found on the AO-18 page.

ESA missions team up to map cosmic rays across Solar System

13 November 2019 ESA spacecraft dotted across the inner Solar System, including INTEGRAL, carried out a census of deep space radiation during an entire 11-year solar cycle – and discovered a location where radiation levels remained mysteriously lower than elsewhere. See the ESA Enabling & Support news. A report on the results was published in the European Geoscience Union’s Annales Geophysicae journal.

Happy 17th birthday, INTEGRAL!

17 Oct 2019  On this date, 17 years ago, INTEGRAL was launched at 01:33 UTC with a Proton rocket from Baikonur, Kazakhstan. INTEGRAL is still operating successfully, and continues to explore the most energetic radiation that comes from space. It is an ESA mission in cooperation with Russia and the United States.

Pierre Mandrou: 20 June 1944 - 25 September 2019

3 Oct 2019 Pierre Mandrou, a colleague at CESR and later IRAP Toulouse, passed away on 25 September, at the end of a courageous fight against his disease. He had 75 years, was retired since 10 years, but remained active.
Pierre had an exceptional career accompanying the evolution of experimental gamma-ray astronomy from the beginnings to its heydays. Since the early 70s, he had started developing balloon-borne gamma-ray detectors (BERENICE, OPALE and FIGARO). Throughout the 80s and until the mid 90s he was Co-PI and Project Manager of the SIGMA coded mask instrument, built with colleagues from CNES, CEA and IKI. He then acted as instrument scientist for ESA's INTEGRAL/SPI, and finally, up to the limits of his strength, he helped with the development on ECLAIRs/SVOM. Pierre also served as technical director of CESR. He was recognized with several awards during his career including the French ordre du mérite and the crystal of the CNRS. Pierre is survived by his wife and two sons.

Target-of-Opportunity observations of CenTAURUS X-3

31 July 2019 INTEGRAL is currently observing the High Mass X-ray Binary Cen X-3. The source is the target selected for the first light of the ART-XC detector onboard the Spektr-RG mission. INTEGRAL observations will provide complementary information of the source at hard X-rays and will help to characterise the performance of the ART-XC detector in space. Spektr-RG was launched from the Baikonur Cosmodrome on 13 July 2019. We wish sucessful operations to our Spektr-RG colleagues.

INTEGRAL AO-17 General Programme Approved

12 July 2019 The INTEGRAL AO-17 General Programme, as recommended by the Time Allocation Committee (TAC) and approved by ESA's Director of Science (Prof. Günther Hasinger), has been released and the observers have been informed. It can be found here

With the help of INTEGRAL, one got to the bottom of a 'spitting' black hole

29 April 2019 Data by INTEGRAL, obtained in 2015 during the outburst of the X-ray transient black-hole binary V404 Cyg, have helped to shed light on the workings of inner parts of the binary. As presented in a Letter to Nature, in the radio, astronomers have recently found that the black hole was spitting out 'bullets' of plasma while rotating through space. The inner part of the accretion disc seems to be tilted with respect to the rest of the system, most likely due to the spin of the black hole being inclined with respect to the orbit of the companion star. INTEGRAL's observations were used to estimate the energy and geometry of the accretion onto the black hole, which in turn were crucial to understand the link between the incoming and outflowing material to create a complete picture of the situation. See the ESA press release for more information.

17th Announcement of Opportunity (AO-17): Preliminary statistics

23 April 2019 The deadline for the submission of proposals for AO-17 open time observations was on 5 April 2019, and all proposals are in the ISOC database. Below are some preliminary statistics on the proposals that have been received.

Total number of proposals
The total number of proposals received is 63. The total observing time requested is about 73 Msec (for all types of observation, i.e., fixed time, normal time, and ToO). Here, 10% of the requested total ToO time has been taken into account. Given that up to about 21 Msec of observing time (for new observing proposals) will be available for the AO-17 observing programme (12 months duration starting on 1 January 2020), this corresponds to an oversubscription in time by a factor of 3.5.

The non-ToO proposals are requesting data rights for 361 sources in total. 22 proposals requested joint time with NuSTAR, Swift and/or XMM-Newton.

Proposals per category
In the following table we give the breakdown of number of proposals as a function of the proposal category. Note that the numbers on requested observing times do include ToO proposals, but it has been assumed here, that a typical ToO proposal requests about 10% of its total observing time as entered into PGT from all the candidate sources included in a ToO proposal.

Scientific Category Number of proposals Requested observing time (Ms)
includes ToO times x 10%
Galactic Astronomy 36 57
Extragalactic Astronomy 16 4
Nucleosynthesis and diffuse
continuum/line emission
11 12
Total 63 73

 

Mid May, the Time Allocation Committee will peer review all proposals and recommend the AO-17 observing programme to ESA.

INTEGRAL, A Human Development

08 March 2019 At the occasion of the 12th INTEGRAL conference, Thierry Courvoisier provided an inspiring after-dinner speech on 12 February 2019, entitled: INTEGRAL, A Human Development.

INTEGRAL AO-17 CALL FOR OBSERVING PROPOSALS IS OPEN!

25 February 2019 Today, the Director of Science (Prof. Guenther Hasinger) has released the 17th Announcement of Opportunity (AO-17) for observing proposals with INTEGRAL.

This announcement solicits proposals for observations to be carried out from January 2020 for a period of 12 months. Proposers from all over the world are welcome to participate. All proposals will be subject to an independent peer review by the INTEGRAL Time Allocation Committee (TAC). The deadline for proposal submission is Friday 5 April 2019, 14:00 CEST.

More information can be found on the AO-17 page.

Target-of-Opportunity observations of MAXI J1348-630

6 February 2019 INTEGRAL is currently observing the candidate black hole X-ray binary MAXI J1348-630. The ongoing outburst, first detected by MAXI on Jan 26th, is being monitoring by INTEGRAL since Revolution 2051 (see ATels #12441, 12457, 12471 and GCN Circ. #23799). Data are provided by two accepted monitoring programs (1640006, PI: Rodríguez; 1640004 PI: Belloni). The data from proposal 1640006 are public.

Preparations for the next announcement of opportunity (AO-17) for requesting observing time with INTEGRAL is underway

25 January 2019 ISOC is preparing the next call for proposals requesting INTEGRAL observing time. The AO-17 release will be already on 25 February, with a deadline on 5 April 2019. The AO-17 cycle of observations is foreseen to begin on 1 January 2020 and has the usual duration of 12 months.

 

Release of AO-17: Call for observing time proposals   25 February 2019
Deadline for submission of observing time proposals   5 April 2019 (14:00 CEST)
Meeting of the Time Allocation Committee (TAC)   13-15 May 2019
Start AO-17 cycle of observation (duration 12 months)   1 January 2020

Team of telescopes finds X-ray engine inside mysterious supernova

10 January 2019 INTEGRAL and XMM-Newton have helped to find a source of powerful X-rays at the centre of an unprecedentedly bright and rapidly evolving stellar explosion that suddenly appeared in the sky earlier this year. See the News item for more information.

News Archive