Education and Public Outreach for Nasa’s Deep Impact Mission

The Deep Impact mission’s Education and Public Outreach (E/PO) program brings the principles of physics relating to the properties of matter, motions and forces and transfer of energy to school-aged and public audiences. Materials and information on the project web site convey the excitement of the mission, the principles of the process of scientific inquiry and science in a personal and social perspective. Members of the E/PO team and project scientists and engineers, share their experiences in public presentations and via interviews on the web. Programs and opportunities to observe the comet before, during and after impact contribute scientific data to the mission and engage audiences in the mission, which is truly an experiment.     

Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI)

The Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) is a five telescope package, which has been developed for the Solar Terrestrial Relation Observatory (STEREO) mission by the Naval Research Laboratory (USA), the Lockheed Solar and Astrophysics Laboratory (USA), the Goddard Space Flight Center (USA), the University of Birmingham (UK), the Rutherford Appleton Laboratory (UK), the Max Planck Institute for Solar System Research (Germany), the Centre Spatiale de Leige (Belgium), the Institut d’Optique (France) and the Institut d’Astrophysique Spatiale (France). SECCHI comprises five telescopes, which together image the solar corona from the solar disk to beyond 1 AU. These telescopes are: an extreme ultraviolet imager (EUVI: 1–1.7 R_⊙), two traditional Lyot coronagraphs (COR1: 1.5–4 R_⊙ and COR2: 2.5–15 R_⊙) and two new designs of heliospheric imagers (HI-1: 15–84 R_⊙ and HI-2: 66–318 R_⊙). All the instruments use 2048×2048 pixel CCD arrays in a backside-in mode. The EUVI backside surface has been specially processed for EUV sensitivity, while the others have an anti-reflection coating applied. A multi-tasking operating system, running on a PowerPC CPU, receives commands from the spacecraft, controls the instrument operations, acquires the images and compresses them for downlink through the main science channel (at compression factors typically up to 20×) and also through a low bandwidth channel to be used for space weather forecasting (at compression factors up to 200×). An image compression factor of about 10× enable the collection of images at the rate of about one every 2–3 minutes. Identical instruments, except for different sizes of occulters, are included on the STEREO-A and STEREO-B spacecraft.     

Dynamical Origin of Comets and Their Reservoirs

It is widely believed that cometary orbits contain important clues to both the outer solar system’s current structure and its past dynamical evolution. The first part of this paper summarizes the results of numerical simulations designed to study the dynamical origins of observed comets and to link the observed populations to the reservoirs from which they are currently leaking. The second part reviews simulations which are designed to study the dynamical origin of the reservoirs themselves. The paper concludes with a brief discussion of the currently unresolved issue of where in the primordial solar nebula the different dynamical classes of observed comets originated.     

Waverider

On 17–19 October 1990 the University of Maryland hosted the 1st International Hypersonic Waverider Symposium. It has been a long wait; and although far more eminent contributors took part, there was also one amateur group. The comeback for the Waverider concept is due in part, at least, to determined advocacy by the amateur group, ASTRA — probably the first case of its kind. Duncan Lunan, President of ASTRA, explains.     

GH169合金的本构关系研究

GH169合金主要是作为变形合金而得到广泛应用。因此,迫切需要明确其流动应力与变形条件的关系,即本构关系。文献[1]曾对GH169合金进行了这方面的研究,但所研究的结果只适用于预成形过程,而且所得到的本构关系与实测数据误差较大。近代航空发动机的涡轮盘广泛采用GH169合金制造,其锻造过程一般由预锻和终锻过程组成。     

Lord Young of Dartington and the Argo Venture

Although best known for his political and social achievements, the late Lord Young was also an early advocate of space exploration and cooperation. This article describes his proposal for a simulated Mars habitation, the ‘Argo Venture’, and the steps that were taken to try and bring it about. Although financial support was ultimately withdrawn in the face of the US Biosphere 2 project, a number of current Mars-related projects suggest that the Argo Venture is not entirely forgotten.