TWINS-2 Energetic Neutral Atom (ENA) Imager

TWINS (Two Wide-angle Imaging Neutral-atom Spectrometers) is a Mission of Opportunity under NASA's Small Explorer (SMEX) program. TWINS-1 and TWINS-2 are the designations for NASA-sponsored instruments flying on unspecified non-NASA U.S. government spacecraft.The TWINS-1 instrument high voltages were turned on in April 2007 and the TWINS-2 high voltages in May 2008; the exact launchdates are not available. The data (including both science data and spacecraft ephemeris/attitude information) from the two NASA-funded science instruments are publicly available to the scientific research community. TWINS instrumentation includes an energetic neutral atom (ENA) imager to capture charge-exchange-produced neutral atoms over a broad energy range (approximately 1-100 keV) and a Lyman-alpha detector to measure the density of the neutral hydrogen geocorona needed for extraction of magnetospheric ion fluxes from neutral atom data. The TWINS-1 and TWINS-2 instruments are identical.

TWINS（双宽场成像中性原子光谱仪）是隶属于美国国家航空航天局（NASA）小型探测器（SMEX）计划的机遇任务。TWINS-1和TWINS-2是NASA资助的仪器，它们搭载在未指定的非NASA美国政府航天器上。TWINS-1仪器的高电压于2007年4月启用，TWINS-2的高电压于2008年5月启用；确切的发射日期尚未公布。来自这两台NASA资助的科学仪器的数据（包括科学数据和航天器视迹/姿态信息）对科学研究界公开。TWINS仪器包括一个高能中性原子成像仪，用于捕获在较宽的能量范围内（约1-100 keV）由电荷交换产生的中性原子，以及一个莱曼-α探测器，用于测量中性氢地冕的密度，这是从中性原子数据中提取磁层离子通量所必需的。TWINS-1和TWINS-2仪器完全相同。