Astrodynamical middle-frequency interferometric gravitational wave observatory AMIGO: Mission concept and orbit design

Abstract

AMIGO is a first-generation Astrodynamical Middle-frequency Interferometric GW Observatory. The scientific goals of AMIGO are: to bridge the spectra gap between first-generation high-frequency and low-frequency GW sensitivities; to detect intermediate mass BH coalescence; to detect inspiral phase and predict time of binary black hole coalescence together with neutron star coalescence for ground interferometers; to detect compact binary inspirals for studying stellar evolution and galactic population. The mission concept is to use time delay interferometry for a nearly triangular formation of 3 drag-free spacecraft with nominal arm length 10,000 km, emitting laser power 2-10 W and telescope diameter 300-360 mm. The design GW sensitivity in the middle frequency band is 3 × 10 −21 Hz -1 . Four options of orbits are under study: (i) Earth-like solar orbits (2-20 degrees behind the Earth); (ii) 600,000 km high orbit formation around the Earth; (iii) 50,000 km-250,000 high orbit formation around the Earth; (iv) near Earth-Moon L4 (or L5) halo orbit formation. All four options have LISAlike formations, that is the triangular formation is 60º inclined to the orbit plane. For AMIGO, the first-generation time delay interferometry is good enough for the laser frequency noise suppression. We also investigate for each options of orbits under study, whether constant equal-arm implementation is feasible. For the solar-orbit option, the acceleration to maintain the formation can be designed to be less than 15 nm/s 2 with the thruster requirement in the 15 μN range. AMIGO would be a good place to implement the constant equal-arm option. Fuel requirement, thruster noise requirement and test mass acceleration actuation requirement are briefly considered. From the orbit study, the solar orbit option is the first mission orbit choice. We study the deployment for this orbit option. A last-stage launch from 300 km LEO (Low Earth Orbit) to an appropriate 2-degree-behindthe-Earth AMIGO formation in 95 days requires only a v of 75 m/s.

New sensitivity curves for gravitational-wave signals from cosmological phase transitions

“…To facilitate such an analysis, we review the strain noise spectra of a number of interferometer and PTA experiments in appendix A. Beyond that, our method could also be extended to experiments that we do not consider in appendix A, such as, e.g., AEDGE [182], AIGSO [183,184], AION [185], AMIGO [186], Taiji [187], TianGO [188], TianQin [189,190], etc. Furthermore, it would be desirable to repeat our xSM analysis in the companion paper [2] for as many BSM models as possible.…”

Orbit design and thruster requirement for various constant arm space mission concepts for gravitational-wave observation

“…25,26 In our study about AMIGO mission which proposed the arm length with 10000 km arm length, we considered a multitude of possible orbital configurations. 15 In this work, the configurations AMIGO-E1, AMIGO-EML4 and AMIGO-S are selected to downscale by 100 times as the possible B-DECIGO orbital configurations. Therefore, we choose one geodesic orbit from the AMIGO configuration as fiducial, and find the other two S/Cs trajectories by scaling down the other two AMIGO arms in the constant-equal-arm formation.…”

“…In the AMIGO constant arm implementation for heliocentric orbit, the acceleration to maintain the formation can be designed to be less than 15 nm/s 2 and the thruster requirement can be smaller than 15 µN. 15 AIGSO is a mission concept using atom interferometry to detect the GWs mainly in the middle frequency band (0.1-10 Hz). 12 AIGSO proposes to have three spacecraft in linear formation with 10 km baseline.…”

Orbit design for space atom-interferometer AIGSO

“…To achieve the targeting orbit, the Clohessy and Wiltshire frame (CW frame) for one body problem could be used to preliminarily design the orbit to keep the approximately constant distance between S/Cs. [38][39][40] In our past works, we used CW frame to calculate/simulate the constellations orbits for LISA, 41 TAIJI, 42 and AMIGO 11 for obtaining preliminary initial conditions and then using the numerical method to optimize them. Now we apply the same procedure to the AIGSO mission orbit design.…”

“…8 The new low-frequency laser-interferometric space GW projects include TAIJI 9 and Tianqin. 10 The new middle-frequency laser-interferometric space GW projects include AMIGO 11,12 and B-DECIGO. 13,14 The middle-frequency GW proposals also include torsion-bar proposal TOBA, 15,16 superconducting sensing proposal SOGRO 17,18 and Doppler tracking proposal using optical clocks INO.…”