A 20 m space telescope is described with an unvignetted 1° field of view—a hundred times larger in area than fields of existing space telescopes. Its diffraction-limited images are a hundred times sharper than from wide-field ground-based telescopes and extend over much if not all the field, 40 arcmin diameter at 500 nm wavelength, for example. The optical system yielding a 1°, 1.36 m diameter image at f/3.9 has relatively small central obscuration, 9% by area on axis, and is fully baffled. Several carousel-mounted instruments can each access directly the full image. The initial instrument complement includes a 400 gigapixel silicon imager with 2 µm pixels (0.005 arcsec), and a 60 gigapixel HgCdTe imager with 5 µm pixels (0.012 arcsec). A multi-object spectrograph with 10 000 fibres will allow spectroscopy with 0.02 arcsec resolution. Direct imaging and spectroscopy of exoplanets can take advantage of the un-aberrated, on-axis image (5 nm RMS wavefront error). While this telescope could be built for operation in free space, a site accessible to a human outpost at the Moon's south pole would be advantageous, for assembly and repairs. The lunar site would allow also for the installation of new instruments to keep up with evolving scientific priorities and advancing technology. Cooling to less than 100E K would be achieved with a surrounding cylindrical thermal shield. This article is part of a discussion meeting issue ‘Astronomy from the Moon: the next decades’.

Multi-object spectroscopy via independently positioned optical fibers is of growing importance in many research areas in astronomy. Currently the most powerful instrument of this type is the Dark Energy Spectroscopic Instrument (DESI), now being commissioned at the 3.8 m Mayall telescope. It has a 3.2° field of view where spectra of 5000 different objects may be recorded simultaneously. Here we present an optical design for a two-mirror 6.5 m telescope with 3.0° field of view, for an etendue 2.6 times larger than for DESI. The images are at f / 3.7 for fiber matching, and —averaged over the field and elevations down to 40°—have a diameter of 0.53 arcsec for 80% encircled energy. We outline methods capable of polishing and testing the 1.56 m diameter gull-wing lens of the wide field corrector. If a 2 m diameter lens could be made, the same design could be scaled up to an 8.4 m primary for a 4.3-fold etendue advantage.

Hydroxide‐aluminum based nano‐energetic materials are new class of thermites which demonstrated high theoretical energy capacity of up to 50 kJ cm−3. Most of the hydroxide‐aluminum based systems exhibit a large gas generation (greater than two liters per gram) and high adiabatic combustion temperature (up to 3000 K), which ensures performance that attributes significantly for applications such as solid fuel propulsion, explosives, airbag deployment, etc. Thermodynamic calculations performed for a collection of 16 novel hydroxide‐based nano‐thermite systems show that most of the systems are stable. Four systems, based on bismuth, copper, nickel and cerium hydroxides, were mixed with aluminum to prepare nano‐thermites compositions. These formulations were tested to estimate the heat generation and pressure discharge values during the ignition. These systems were stable below ignition temperature, between 570–600 °C. The strongest performance was recorded for Al−Bi(OH)3 formulation with 5.6 kPa*m3 g−1 peak pressure, which is comparable to highest values reported in literature.