Extending the lifetime of ESA's X-ray observatory XMM-Newton

Kirsch, Marcus; Elfving, Anders; Kresken, Rainer; McDonald, Alastair; Martin, Jim; Pantaleoni, Mauro; Pfeil, Norbert; Strandberg, Tommy; Vandersteen, Jeroen; Webert, Detlef; Weissmann, Uwe

doi:10.2514/6.2014-1608

Cited by 8 publications

(4 citation statements)

References 7 publications

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“…Dry bearing cage instability anomalies with symptoms very similar to those described earlier have also been observed in two (of four) attitude control reaction wheels of the ESA mission XMMNewton [16,17]. The XMM-Newton observatory was launched in 1999 for a 10 year mission.…”

Section: Cassini Rwa Bearing Cage Instabilitymentioning

confidence: 54%

In-Flight Performance of Cassini Reaction Wheel Bearing Drag in 1997–2013

Lee

Wang

2015

Journal of Spacecraft and Rockets

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As the first spacecraft to achieve orbit at Saturn in 2004, Cassini has collected science data throughout its four year prime mission (2004)(2005)(2006)(2007)(2008) and has since been approved for a first and second extended mission through September 2017. Cassini uses reaction wheels to achieve the spacecraft pointing stability that is needed during imaging operations of several science instruments. The Cassini flight software makes in-flight estimates of reaction wheel bearing drag torque and made them available to the mission operations team. In trending these telemetry data (for the purpose of monitoring the long-term health of the reaction wheel bearings), anomalous drag torque signatures have been observed over the past 15 years. One of these anomalous drag conditions is bearing cage instability that appeared (and disappeared) spontaneously and unpredictably. Cage instability is an uncontrolled vibratory motion of the bearing cage that can produce high-impact forces internal to the bearing, which will cause intermittent and erratic torque transients. Characteristics of the observed cage instabilities and other drag torque "spikes" are described in this paper. In day-to-day operations, the reaction wheels' rates must be neither too high nor too low. To protect against operating the wheels in any undesirable conditions (such as prolonged low spin rate operations), a ground software tool named a reaction wheel bias optimization tool was developed for the management of the wheels. Flight experience on the use of this ground software tool, as well as other lessons learned on the management of Cassini reaction wheels, is given in this paper.Nomenclatures c = viscous coefficient of wheel bearing lubrication system, N · m · s∕rad Gω = function of wheel spin rate ω defined in Eq. (5) I RWA = moment of inertia of reaction wheel rotor, kg · m 2 K I = integrator gain of reaction wheel assembly drag torque estimator, kg · m 2 ∕s 2 K P = proportional gain of reaction wheel assembly drag torque estimator, kg · m 2 ∕s L −1 = inverse Laplace operator s = Laplace variable, rad∕s T D = Dahl drag torque of reaction wheel bearing system, N · m T Drag = total drag torque of reaction wheel bearing system, N · m ξ D = damping ratio of reaction wheel assembly drag torque estimator τ = time constant of wheel speed decay [see Eq. (4)], s Ω 0 = initial wheel spin rate of coast-down test, rad∕s ω = angular rate of the reaction wheel, rad∕s ω D = bandwidth of the reaction wheel assembly drag torque estimator, rad∕s

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Section: Cassini Rwa Bearing Cage Instabilitymentioning

confidence: 54%

In-Flight Performance of Cassini Reaction Wheel Bearing Drag in 1997–2013

Lee

Wang

2015

Journal of Spacecraft and Rockets

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“…Such a solution has already been implemented and successfully commissioned on XMMNewton [12] and would certainly be technically feasible for INTEGRAL. It would lead to a fuel saving in the order of 50%.…”

Section: Ii1 Adaptation Of the Xmm 4-wheel-drive Solution For Use Onmentioning

confidence: 97%

Run, INTEGRAL, run! Low wheel speed operations for fuel savings

Huebner¹,

Southworth²,

Seiler³

et al. 2016

SpaceOps 2016 Conference

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In early 2015, ESA's high energy astronomical observatory INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory) performed a series of manoeuvres to enable the disposal of INTEGRAL via an uncontrolled re-entry into the Earth's atmosphere in 2029. These manoeuvres used approximately half of INTEGRAL's remaining fuel. At the current rate of consumption, fuel would be exhausted by early 2020 already and thus probably be the satellite's lifetime limiting element. Following these manoeuvres, different ways to reduce propellant usage were investigated.This paper summarises the general concepts of various fuel saving options. Indications suggest that it is possible to achieve major propellant savings in the coming years at very low implementation costs. This could allow ESA to extend INTEGRAL's science operations phase considerably and thus provide the high energy astronomical community with a solid observatory well into the next decade. Furthermore, it could possibly even allow for a controlled re-entry in 2029 with some residual propellant available for a trim manoeuvre in the mid to late 2020ies. Such a manoeuvre would enable ESA to fine-tune the re-entry longitude, position and profile.

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“…ESA's XMM-Newton X-ray space observatory has already been in orbit for 16 years and is still operating without any significant unexpected degradation 5) . The almost permanent coverage from the ground station network and the limited autonomy on-board leave room for a powerful automation system.…”

Section: B Conclusionmentioning

confidence: 99%

Automated on-ground FDIR for ESA’s XMM-Newton mission

Godard¹,

Weissmann²,

Toma³

et al. 2016

SpaceOps 2016 Conference

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The flagship of European X-ray astronomy, ESA's XMM-Newton space observatory, was launched in 1999 with an expected lifetime of up to ten years. Through an operational change of the AOCS system, we extended its potential lifetime until the late 20ies of this century. Spacecraft and instruments are performing without major degradation. Because of the highly elliptical orbit, the spacecraft is permanently visible from the ground station network. For this and other reasons, the originally chosen on-board autonomy design is very limited. Fifteen years of inflight experience created a deep understanding of the spacecraft behavior including elaborated strategies and procedures to recover from reoccurring non-critical anomalies on board. Based on this experience, an automated ground failure detection system has been developed to provide reliable fault isolation and adapted reaction. We present here the system put in place to conduct automatically some of the nominal XMM-Newton operations and share our experience with the automatic contingency recovery tool after half a year of usage. The on-ground Failure Detection, Isolation and Recovery (FDIR) system is able to read various sorts of anomaly messages, either from the spacecraft (telemetry being out-of-limit), from the ground segment (link loss) or from the mission control software (an application stopped). Upon detection of anomaly, the automation system starts the execution of a procedure to confirm its consistency and persistency to avoid over reaction to minor events. Once the anomaly has been confirmed and identified, the recovery is kicked off under the supervision of the operator or autonomously. The targeted level of automation shall release the operator from activities that were so far manually performed, let him concentrate on other activities running in parallel, reduce the stress in contingency situations and lessen the probability of human error.

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Extending the lifetime of ESA's X-ray observatory XMM-Newton

Cited by 8 publications

References 7 publications

In-Flight Performance of Cassini Reaction Wheel Bearing Drag in 1997–2013

In-Flight Performance of Cassini Reaction Wheel Bearing Drag in 1997–2013

Run, INTEGRAL, run! Low wheel speed operations for fuel savings

Automated on-ground FDIR for ESA’s XMM-Newton mission

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