The possible formation and evolution of dwarf irregular galaxies from material derived from perturbed evolved galaxies is addressed via an H 1 study of a likely example, the peculiar system NGC 5291. This 1427 Astron.

We present 21 cm observations of Arp 158. We have performed a study of the neutral hydrogen ( H i) to help us understand the overall formation and evolution of this system. This is a disturbed system with distinct optical knots connected by a linear structure embedded in luminous material. There is also a diffuse spray to the southeast. The H i seems to be made up of three distinct, kinematically separate systems. Arp 158 bears a certain optical resemblance to NGC 520 (Arp 157), which has been identified as a mid-stage merger. From our 21 cm observations of Arp 158, we also see a comparable H i content with NGC 520. These similarities suggest that Arp 158 is also an intermediate-stage merger.

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As small spacecraft venture out of Earth orbit, they will encounter challenges not experienced or addressed by the numerous low Earth orbit (LEO) CubeSat and Smallsat missions staged to date. The LEO CubeSats typically use low-cost, proven CubeSat radios, antennas, and university ground stations with small apertures. As more ambitious yet cost-constrained space mission concepts to the Moon and beyond are being developed, CubeSats and smallsats have the potential to provide a more affordable platform for exploring deep space and performing the associated science. Some of the challenges that have, so far, slowed the proliferation of small interplanetary spacecraft are those of communications and navigation. In [23], we discussed the communications and tracking challenges facing interplanetary smallsats and CubeSats, and the next-generation ground network architecture being evolved to mitigate those challenges. In this paper we summarized the results in [23]. Based on our understanding on the mission set of interplanetary smallsats and ground network architecture, we discuss the preliminary thoughts on the operations concept that would transform the current DSN architecture to a federated network architecture that, in addition to traditional deep space missions, can also provide just-in-time communications and tracking services to a large number of interplanetary smallsats/CubeSats. We focus on the following topics:1. DSN compatibility and interfaces. Challenges on integrating heterogeneous non-DSN antennas into the DSN service management and service execution framework.3. Cross-support with university antennas, with other space agencies, and with other research centers.4. Network planning and scheduling concepts that maximize pass opportunities for smallsats and CubeSats.