Atomic Clock Ensemble in Space
The Atomic Clock Ensemble in Space ( ACES for short ) is one of the external experimental laboratories to be attached to the Columbus Space Laboratory , ESA's science laboratory for the International Space Station . A payload pallet is used for this; the pallet facing the earth is intended for ACES . It is not to be confused with SolACES , an attempt to measure the effects of VUV radiation . ACES is used to test a new generation of atomic clocks under the conditions of microgravity. This should enable a more precise global time determination (e.g. for GNSS , especially Galileo ) as well as an evaluation of the theory of relativity . Astrium has been commissioned with the production .
The entire unit should have a mass of 227 kg and an electrical power consumption of 470 W. The test duration is set at 18 months. Launch is currently planned for 2020 on board a Dragon capsule .
Technical details
The core of the experiment is an arrangement of two atomic clocks that work according to different methods. The data transmission to earth should also take place via two transmission paths, on the one hand via microwaves and on the other via a laser link . The purpose of this is to clarify running time effects, the running speed of waves is not constant. One uplink connection is established in the Ku band , two downlink connections in the S and Ku band.
As clocks PHARAO (Projet d'Horloge Atomique par refroidissement d'en atom orbite) as laser-cooled cesium -Watch (cold Cs clock) and SHM (Space Hydrogen Maser) as a hydrogen maser used. The design of PHARAO was adapted to the knowledge gained so far about influences on atomic clocks in orbit. For this purpose, zero-G tests were carried out with the ESA A300 with a PHARAO prototype , with CNES responsible for this, which PHARAO developed and completed in July 2014.
Both clocks are synchronized by an internal ACES evaluation computer , which is called FCDP (Frequency Comparison and Distribution Package). The time signals for the downlink are also processed here.
Ground stations for experiments
For experiments with ACES , a number of ground stations are provided that operate reference clocks of various types:
- Australia:
- Brazil:
- University of Sao Carlos
- China:
- NTSC
- NIM
- Shanghai observatory
- Germany:
- Physikalisch-Technische Bundesanstalt in Braunschweig
- Max Planck Institute for Quantum Optics in Garching
- Gottfried Wilhelm Leibniz University of Hanover
- Heinrich-Heine-University Dusseldorf
- Technical University of Munich
- Friedrich-Alexander University Erlangen-Nuremberg
- France:
- CNES
- SYRTE in Paris
- Laboratoire de Physique des Lasers in Villetaneuse (LPL)
- Besançon Observatory
- OCA
- Great Britain:
- Italy:
- Japan:
- Tokyo University
- National Metrology Institute of Japan (NMIJ)
- Communications Research Laboratory in Tokyo (CRL)
- Canada:
- National Research Council (NRC)
- Austria:
- Russia:
- VNIIFTRI in Mendelejewo (Moscow)
- ILS in Novosibirsk
- Switzerland:
- Federal Metrology Office (METAS)
- UNITED STATES:
- Jet Propulsion Laboratory in Pasadena, California
- United States Naval Observatory (USNO)
- National Institute of Standards and Technology (NIST)
Additional external payloads from Columbus
- European Technology Exposure Facility (EuTEF)
- Solar Monitoring Observatory (SMO / SOLAR)
See also
- Primary Atomic Reference Clock in Space (PARCS)
- Superconducting Microwave Oscillator (SUMO)
- Rubidium Atomic Clock Experiment (RACE)
literature
- Luigi Cacciapuoti and Christophe Salomon : Atomic clock ensemble in space . In: Journal of Physics: Conference Series . tape 327 , 2011, pp. 012049 , doi : 10.1088 / 1742-6596 / 327/1/012049 (English).
- Mauro Augelli: ACES Operations: an ISS External Scientific Payload Looking for Experimental Confirmations on the General Relativity Theory . In: Proceedings of the 14th International Conference on Space Operations (SpaceOps 2016), Daejeon, Korea, May 16-20, 2016 . 2016, doi : 10.2514 / 6.2016-2407 (English, online [PDF; accessed on January 13, 2017]).
Web links
- ESA: ISS Utilization: ACES (Atomic Clock Ensemble in Space) / PHARAO. Retrieved January 13, 2017 .
- Website of the ACES project at CNES: ACES. September 2, 2016, accessed January 13, 2017 .
- ESA: ACES factsheet. Retrieved January 13, 2017 .
- ESA: Atomic Clock Ensemble in Space (ACES) ( Memento from October 16, 2012 in the Internet Archive )
- ESA: (ACES) Factsheet ( Memento from February 27, 2009 in the Internet Archive ) (English, 4 pages, PDF , 1.3 MB)
Individual evidence
- ^ ISS Utilization: ACES / PHARAOH - eoPortal Directory - Satellite Missions. Retrieved December 18, 2018 (American English).
- ↑ Timely arrival of PHARAOH space clock. July 25, 2014, accessed January 13, 2017 .