The Ultra-Fast Flash Observatory (UFFO) Pathfinder is a space observatory measuring prompt emission of

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milli ...

s (GRB) both in optical/UV and in X-ray range down to sub-second timescales for the first time. Instead of turning the whole satellite towards GRB location like the

Swift Gamma-Ray Burst Mission Neil Gehrels Swift Observatory, previously called the Swift Gamma-Ray Burst Explorer, is a NASA three-telescope space observatory for studying gamma-ray bursts (GRBs) and monitoring the afterglow in X-ray, and UV/Visible light at the location o ...

(that takes about 100 seconds), UFFO employs a slewing mirror telescope approach – the optical path of the telescope is changed by rotation of motorized mirror within ~1 second after burst was detected. UFFO was launched April 28, 2016 on board the Mikhailo Lomonosov satellite during the first launch from the new Russian

Vostochny Cosmodrome The Vostochny Cosmodrome (russian: Космодром Восточный, ''Kosmodrom Vostochny'', "Eastern Spaceport") is a Russian spaceport (still partly under construction) above the 51st parallel north in the Amur Oblast, in the Russian ...

Instruments

UFFO Burst Alert & Trigger telescope (UBAT)

UBAT is a wide-field coded mask X-ray camera. It has a 191 cm² detecting area, 90.2°×90.2° field of view and is sensitive in the 15-150 keV photon energy range. UBAT is able to localize bursts with an accuracy of 7σ to a region 10 arcmin across in less than one second time and is used as a trigger source for the SMT.

Slewing Mirror Telescope (SMT)

The SMT is a key component of the UFFO - a telescope designed for fast observation of prompt optical/UV emissions of GRB. SMT consist of the slewing mirror stage, the

Ritchey–Chrétien telescope A Ritchey–Chrétien telescope (RCT or simply RC) is a specialized variant of the Cassegrain telescope that has a hyperbolic primary mirror and a hyperbolic secondary mirror designed to eliminate off-axis optical errors (coma). The RCT has a ...

and image processing / motor controlling electronics. The SMT has 100 mm diameter aperture '' (although it is often mistakenly reported to have 20 cm aperture on various web pages)'', 17×17 arcmin field of view, 4 arcsec angular resolution and is able to register single photons in the 200 nm - 650 nm wavelength range due to using an ICCD as a detector.

UFFO Data Acquisition (UDAQ)

The UDAQ is in charge of UFFO control by execution of an on-board command list. It may also implement commands from the ground. UDAQ collects data both from UBAT and SMT, storing it in several NOR flash memories and transferring to the spacecraft. It is also in charge of temperature / power / light control (the last one is especially important, because the sensitive detectors of the SMT and UBAT must be powered off on the day side of the orbit). As in the UBAT and SMT, the UDAQ's electronics is based on a

FPGA A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term ''Field-programmability, field-programmable''. The FPGA configuration is generally specifi ...

rather than on a

CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...

like most other satellites.

Mission goals

The objective of the UFFO is probing the early optical rise of GRBs for the first time. The first 100 seconds of a GRB optical/UV emission, which has hardly been studied up to now. It takes a long time for ground telescopes to focus on the relevant part of the sky after a GRB is registered. In particular, this may help to understand the evolution of the universe at a high

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...

z>10.

References