16 research outputs found
Funktionstests der Nutzlast fĂŒr die MICROSCOPE-Mission : Freifalltests am Fallturm Bremen
The payload of the french space mission MICROSCOPE containing two differential accelerometers had to be tested in zero-g conditions before launch. By using special drop capsules at the drop tower Bremen at ZARM (University of Bremen) it was possible to test the payload successfully and to demonstrate the correct function of the system. The MICROSCOPE mission aims at testing the Weak Equivalence Principle (WEP) with a new level of accuracy. The correct function of the payload was an important requirement to achieve the mission goal. Another part of the thesis is the development of a new technique for measuring the accelerometer bias by using the catapult mode of the drop tower
Odyssey 2 : A mission toward Neptune and Triton to test General Relativity
Odyssey 2 will be proposed in December 2010 for the next call of M3 missions
for Cosmic Vision 2015-2025. This mission, under a Phase 0 study performed by
CNES, will aim at Neptune and Triton. Two sets of objectives will be pursued.
The first one is to perform a set of gravitation experiments at the Solar
System scale. Experimental tests of gravitation have always shown good
agreement with General Relativity. There are however drivers to continue
testing General Relativity, and to do so at the largest possible scales. From a
theoretical point of view, Einstein's theory of gravitation shows
inconsistencies with a quantum description of Nature and unified theories
predict deviations from General Relativity. From an observational point of
view, as long as dark matter and dark energy are not observed through other
means than their gravitational effects, they can be considered as a
manifestation of a modification of General Relativity at cosmic scales. The
scientific objectives are to: (i) test the gravitation law at the Solar System
scale; (ii) measure the Eddington parameter; and (iii) investigate the
navigation anomalies during fly-bys. To fulfil these objectives, the following
components are to be on board the spacecraft: (i) the Gravity Advanced Package
(GAP), which is an electrostatic accelerometer to which a rotating stage is
added; (ii) radio-science; (iii) laser ranging, to improve significantly the
measure of the Eddington parameter. The second set of objectives is to enhance
our knowledge of Neptune and Triton. Several instruments dedicated to
planetology are foreseen: camera, spectrometer, dust and particle detectors,
and magnetometer. Depending on the ones kept, the mission could provide
information on the gravity field, the atmosphere and the magnetosphere of the
two bodies as well as on the surface geology of Triton and on the nature of the
planetary rings around Neptune.Comment: 61st International Astronautical Congress (Prague, Czech Republic -
September 2010), 7 page
Astrodynamical Space Test of Relativity using Optical Devices I (ASTROD I) - A class-M fundamental physics mission proposal for Cosmic Vision 2015-2025: 2010 Update
This paper on ASTROD I is based on our 2010 proposal submitted for the ESA
call for class-M mission proposals, and is a sequel and an update to our
previous paper [Experimental Astronomy 23 (2009) 491-527; designated as Paper
I] which was based on our last proposal submitted for the 2007 ESA call. In
this paper, we present our orbit selection with one Venus swing-by together
with orbit simulation. In Paper I, our orbit choice is with two Venus
swing-bys. The present choice takes shorter time (about 250 days) to reach the
opposite side of the Sun. We also present a preliminary design of the optical
bench, and elaborate on the solar physics goals with the radiation monitor
payload. We discuss telescope size, trade-offs of drag-free sensitivities,
thermal issues and present an outlook. ASTROD I is a planned interplanetary
space mission with multiple goals. The primary aims are: to test General
Relativity with an improvement in sensitivity of over 3 orders of magnitude,
improving our understanding of gravity and aiding the development of a new
quantum gravity theory; to measure key solar system parameters with increased
accuracy, advancing solar physics and our knowledge of the solar system; and to
measure the time rate of change of the gravitational constant with an order of
magnitude improvement and the anomalous Pioneer acceleration, thereby probing
dark matter and dark energy gravitationally. It is envisaged as the first in a
series of ASTROD missions. ASTROD I will consist of one spacecraft carrying a
telescope, four lasers, two event timers and a clock. Two-way, two-wavelength
laser pulse ranging will be used between the spacecraft in a solar orbit and
deep space laser stations on Earth, to achieve the ASTROD I goals.Comment: 15 pages, 11 figures, 1 table, based on our 2010 proposal submitted
for the ESA call for class-M mission proposals, a sequel and an update to
previous paper [Experimental Astronomy 23 (2009) 491-527] which was based on
our last proposal submitted for the 2007 ESA call, submitted to Experimental
Astronom
MICROSCOPE mission: first results of a space test of the equivalence principle
According to the weak equivalence principle, all bodies should fall at the same rate in a gravitational field. The MICROSCOPE satellite, launched in April 2016, aims to test its validity at the 10â15 precision level, by measuring the force required to maintain two test masses (of titanium and platinum alloys) exactly in the same orbit. A nonvanishing result would correspond to a violation of the equivalence principle, or to the discovery of a new long-range force. Analysis of the first data gives ÎŽ(Ti,Pt)=[â1±9(stat)±9(syst)]Ă10â15 (1Ï statistical uncertainty) for the titanium-platinum Eötvös parameter characterizing the relative difference in their free-fall accelerations
Astrodynamical Space Test of Relativity Using Optical Devices I (ASTROD I)âA class-M fundamental physics mission proposal for Cosmic Vision 2015â2025
Payload Test for the MICROSCOPE-Mission : Free Fall Tests at the Drop Tower Bremen
The payload of the french space mission MICROSCOPE containing two differential accelerometers had to be tested in zero-g conditions before launch. By using special drop capsules at the drop tower Bremen at ZARM (University of Bremen) it was possible to test the payload successfully and to demonstrate the correct function of the system. The MICROSCOPE mission aims at testing the Weak Equivalence Principle (WEP) with a new level of accuracy. The correct function of the payload was an important requirement to achieve the mission goal. Another part of the thesis is the development of a new technique for measuring the accelerometer bias by using the catapult mode of the drop tower