  Here we propose a new gamma-ray burst (GRB) mission, the Next Generation
Rapid-Response GRB Observatory (NGRG). As with Swift, GRBs are initially
located with a coded-mask X-ray camera. However, the NGRG has two new features:
First, a beam-steering system to begin optical observations within ~ 1 s after
location; second, a near-IR (NIR) camera viewing the same sky, for sensitivity
to extinguished bursts. These features allow measurement of the rise phase of
GRB optical-NIR emission. Thus far, the rise time and transition between prompt
and afterglow in the optical and NIR are rarely measured. Rapid-response
measurements explore many science topics including optical emission mechanisms
(synchrotron vs. SSC, photospheric emission) and jet characteristics (reverse
vs. forward shock emission, baryon-dominated vs. magnetic dominated). Rapid
optical-NIR response can measure dynamic evolution of extinction due to
vaporization of dust, and separate star system and galaxy dust extinction. We
discuss these measurements, giving reliable detection rate estimates from
analysis of Swift data and scaled Swift performance. The NGRG will explore
optical/NIR emission measured earlier than ever before, and potentially
fainter, more extinguished GRBs than ever before. In the current era, costs are
important. Our proposed modest NGRG can still produce new GRB science, while
providing rapid GRB alerts for the entire community for post-Swift GRB science.
We show that an X-ray instrument barely 1/5 the area of Swift BAT will yield a
significant fraction of Swift's detection rate: more than 65 X-ray, and with a
30 cm optical-IR telescope and modern cameras, more than 19 NIR and 14 optical
detections each year. In addition, active feedback control of the beam-steering
would remove the need for arc sec stabilization of the spacecraft, for a
substantial cost saving.
