Park, I H13; Brandt, Søren1; Budtz-Jørgensen, Carl1; Castro-Tirado, A J4; Chen, P14; Connell, P6; Eyles, C6; Grossan, B7; Huang, M-H A8; Jeong, S15; Jung, A15; Kim, J E15; Kim, S-W10; Lee, J13; Lim, H13; Linder, E V15; Liu, T-C14; Min, K W11; Na, G W15; Nam, J W14; Panasyuk, M I12; Reglero, V6; Ripa, J13; Rodrigo, J M6; Smoot, G F15; Svertilov, S12; Vedenkin, N12; Yashin, I12
1 National Space Institute, Technical University of Denmark2 Astrophysics, National Space Institute, Technical University of Denmark3 Sungkyunkwan University4 Instituto de Astrofísica de Andalucía5 National Taiwan University6 Universidad de Valencia7 University of California at Berkeley8 National United University9 Ewha Womans University10 Yonsei University11 Korea Advanced Institute of Science & Technology12 Moscow Lomonosov State University13 Sungkyunkwan University14 National Taiwan University15 Ewha Womans University
One of the least documented and understood aspects of gamma-ray bursts (GRBs) is the rise phase of the optical light curve. The Ultra-Fast Flash Observatory (UFFO) is an effort to address this question through extraordinary opportunities presented by a series of space missions including a small spacecraft observatory. The UFFO is equipped with a fast-response Slewing Mirror Telescope (SMT) that uses a rapidly moving mirror or mirror array to redirect the optical beam rather than slewing the entire spacecraft to aim the optical instrument at the GRB position. The UFFO will probe the early optical rise of GRBs with sub-second response, for the first time, opening a completely new frontier in GRBs and transient studies. Its fast response measurements of the optical emission of dozens of GRBs each year will provide unique probes of the burst mechanism and test the prospect of GRBs as a new standard candle, potentially opening up the z > 10 universe. For the first time we employ a motorized slewing stage in SMT that can point to the event within 1 s after the x-ray trigger provided by the UFFO Burst Alert and Trigger Telescope. These two scientific instruments comprise the UFFO-pathfinder payload, which will be placed onboard the Lomonosov satellite and launched in 2013. The UFFO-pathfinder is the first step of our long-term program of space instruments for rapid-response GRB observations. We describe early photon science, our soon-to-be-launched UFFO-pathfinder hardware and mission, and our next planned mission, the UFFO-100.