The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform

K Zhang - One of the best experts on this subject based on the ideXlab platform.

  • An analysis of very short-arc orbit determination for low-Earth objects using sparse optical and laser tracking data
    Advances in Space Research, 2015
    Co-Authors: J.c. Bennett, J. Sang, K Zhang
    Abstract:

    The requirement to regularly track an increasing number of objects will result in straining existing tracking networks. This paper investigates the orbit prediction capability of an orbit determination process using very short-arc optical and laser debris tracking data for objects in low-Earth orbits. An analysis is carried out to determine the reduction in orbit prediction accuracy when tracking data over 5 s from each pass is only available for an orbit determination. The results show that the reduction in accuracy is not extensive and good orbit predictions are still possible when using only 5 s of data from the beginning of each pass. The results are achievable due to an accurate ballistic coefficient estimation and accurate tracking data. The dependence of the results on the Perigee Altitude of the objects is obvious, indicating modelling error of the atmospheric mass density in lower orbits remains the dominant source of error.

J.c. Bennett - One of the best experts on this subject based on the ideXlab platform.

  • An analysis of very short-arc orbit determination for low-Earth objects using sparse optical and laser tracking data
    Advances in Space Research, 2015
    Co-Authors: J.c. Bennett, J. Sang, K Zhang
    Abstract:

    The requirement to regularly track an increasing number of objects will result in straining existing tracking networks. This paper investigates the orbit prediction capability of an orbit determination process using very short-arc optical and laser debris tracking data for objects in low-Earth orbits. An analysis is carried out to determine the reduction in orbit prediction accuracy when tracking data over 5 s from each pass is only available for an orbit determination. The results show that the reduction in accuracy is not extensive and good orbit predictions are still possible when using only 5 s of data from the beginning of each pass. The results are achievable due to an accurate ballistic coefficient estimation and accurate tracking data. The dependence of the results on the Perigee Altitude of the objects is obvious, indicating modelling error of the atmospheric mass density in lower orbits remains the dominant source of error.

J. Sang - One of the best experts on this subject based on the ideXlab platform.

  • An analysis of very short-arc orbit determination for low-Earth objects using sparse optical and laser tracking data
    Advances in Space Research, 2015
    Co-Authors: J.c. Bennett, J. Sang, K Zhang
    Abstract:

    The requirement to regularly track an increasing number of objects will result in straining existing tracking networks. This paper investigates the orbit prediction capability of an orbit determination process using very short-arc optical and laser debris tracking data for objects in low-Earth orbits. An analysis is carried out to determine the reduction in orbit prediction accuracy when tracking data over 5 s from each pass is only available for an orbit determination. The results show that the reduction in accuracy is not extensive and good orbit predictions are still possible when using only 5 s of data from the beginning of each pass. The results are achievable due to an accurate ballistic coefficient estimation and accurate tracking data. The dependence of the results on the Perigee Altitude of the objects is obvious, indicating modelling error of the atmospheric mass density in lower orbits remains the dominant source of error.

Mike Walker - One of the best experts on this subject based on the ideXlab platform.

  • 1 INTEGRAL Revisits Earth- Low Perigee Effects on Spacecraft Components
    2015
    Co-Authors: Jutta M. Hübner, Richard T. Southworth, Alastair Mcdonald, Peter Kretschmar, Carmen Lozano, Mike Walker, Scysis Deutschland Gmbh Darmstadt
    Abstract:

    (INTEGRAL) has been observing astronomical objects simultaneously in gamma-rays, X-rays and visible light. Using its four instruments, it provides insight into the nature of sources of extremely high-energy radiation, and 9 years after its launch the scientific interest is still very high. The performance of INTEGRAL has far exceeded design specifications. To date, it is still the most sensitive gamma ray observatory in space, all prime units are still in use, no major failures have occurred and the degradation of spacecraft components is minimal. Last but not least, the nominal lifetime of two years has already been far exceeded, and the remaining fuel on board still allows for another decade of operations. Major challenges the mission faces are the orbital evolution and the aging of spacecraft components: on October 25th 2011, INTEGRAL reached the lowest Perigee Altitude since its launch. This resulted in both increased exposure to proton radiation during Perigee passage and an increased heating of the spectrometer’s cryocooler due to the Earth albedo, leading to a small reduction in payload performance. Furthermore, all electrical components will have reached their total dose qualification limit soon. This paper summarizes the effects of the period of low Perigee Altitude on th

  • INTEGRAL Revisits Earth - Low Perigee Effects on Spacecraft Components
    SpaceOps 2012 Conference, 2012
    Co-Authors: Jutta M. Hübner, Alastair Mcdonald, Peter Kretschmar, Carmen Lozano, Richard Southworth, Mike Walker
    Abstract:

    Since its launch in 2002, ESA's INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) has been observing astronomical objects simultaneously in gamma-rays, Xrays and visible light. Using its four instruments, it provides insight into the nature of sources of extremely high-energy radiation, and 9 years after its launch the scientific interest is still very high. The performance of INTEGRAL has far exceeded design specifications. To date, it is still the most sensitive gamma ray observatory in space, all prime units are still in use, no major failures have occurred and the degradation of spacecraft components is minimal. Last but not least, the nominal lifetime of two years has already been far exceeded, and the remaining fuel on board still allows for another decade of operations. Major challenges the mission faces are the orbital evolution and the aging of spacecraft components: on October 25th 2011, INTEGRAL reached the lowest Perigee Altitude since its launch. This resulted in both increased exposure to proton radiation during Perigee passage and an increased heating of the spectrometer’s cryocooler due to the Earth albedo, leading to a small reduction in payload performance. Furthermore, all electrical components will have reached their total dose qualification limit soon. This paper summarizes the effects of the period of low Perigee Altitude on the degradation of the materials and spacecraft components. Furthermore, it presents the associated countermeasures, operational strategies as well as the impact on the fuel consumption and the science. Finally, the prospects for future INTEGRAL operations are summarized along with the lessons learned from the period of low Perigee.

Jutta M. Hübner - One of the best experts on this subject based on the ideXlab platform.

  • 1 INTEGRAL Revisits Earth- Low Perigee Effects on Spacecraft Components
    2015
    Co-Authors: Jutta M. Hübner, Richard T. Southworth, Alastair Mcdonald, Peter Kretschmar, Carmen Lozano, Mike Walker, Scysis Deutschland Gmbh Darmstadt
    Abstract:

    (INTEGRAL) has been observing astronomical objects simultaneously in gamma-rays, X-rays and visible light. Using its four instruments, it provides insight into the nature of sources of extremely high-energy radiation, and 9 years after its launch the scientific interest is still very high. The performance of INTEGRAL has far exceeded design specifications. To date, it is still the most sensitive gamma ray observatory in space, all prime units are still in use, no major failures have occurred and the degradation of spacecraft components is minimal. Last but not least, the nominal lifetime of two years has already been far exceeded, and the remaining fuel on board still allows for another decade of operations. Major challenges the mission faces are the orbital evolution and the aging of spacecraft components: on October 25th 2011, INTEGRAL reached the lowest Perigee Altitude since its launch. This resulted in both increased exposure to proton radiation during Perigee passage and an increased heating of the spectrometer’s cryocooler due to the Earth albedo, leading to a small reduction in payload performance. Furthermore, all electrical components will have reached their total dose qualification limit soon. This paper summarizes the effects of the period of low Perigee Altitude on th

  • INTEGRAL Revisits Earth - Low Perigee Effects on Spacecraft Components
    SpaceOps 2012 Conference, 2012
    Co-Authors: Jutta M. Hübner, Alastair Mcdonald, Peter Kretschmar, Carmen Lozano, Richard Southworth, Mike Walker
    Abstract:

    Since its launch in 2002, ESA's INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) has been observing astronomical objects simultaneously in gamma-rays, Xrays and visible light. Using its four instruments, it provides insight into the nature of sources of extremely high-energy radiation, and 9 years after its launch the scientific interest is still very high. The performance of INTEGRAL has far exceeded design specifications. To date, it is still the most sensitive gamma ray observatory in space, all prime units are still in use, no major failures have occurred and the degradation of spacecraft components is minimal. Last but not least, the nominal lifetime of two years has already been far exceeded, and the remaining fuel on board still allows for another decade of operations. Major challenges the mission faces are the orbital evolution and the aging of spacecraft components: on October 25th 2011, INTEGRAL reached the lowest Perigee Altitude since its launch. This resulted in both increased exposure to proton radiation during Perigee passage and an increased heating of the spectrometer’s cryocooler due to the Earth albedo, leading to a small reduction in payload performance. Furthermore, all electrical components will have reached their total dose qualification limit soon. This paper summarizes the effects of the period of low Perigee Altitude on the degradation of the materials and spacecraft components. Furthermore, it presents the associated countermeasures, operational strategies as well as the impact on the fuel consumption and the science. Finally, the prospects for future INTEGRAL operations are summarized along with the lessons learned from the period of low Perigee.