Review of Fine Guidance Sensor astrometry with HST

Benedict et al. "Astrometry with Hubble Space Telescope Fine Guidance Sensors - A Review"
https://arxiv.org/abs/1610.05176

Some of this is applicable to exoplanets. The final section "The Future" also provides some interesting bits of information...

The effects of the Gaia mission:

Quote :

The first promise that Gaia delivered on was to shut down HST/FGS POS mode astrometry, long before Gaia launch and any evidence of success. Only two FGS POS mode proposals have succeeded in getting time since 2011 (a total of eight orbits).

And if you were wondering what had happened to the plan to analyse some more exoplanetary systems:

Quote :

Funding issues have delayed the final analysis of FGS 1r measures of the exoplanetary systems μ Ara, HD 202206, and γ Cep, with results likely available next year.