SHAPE (Spectro-polarimetry of HAbitable Planet Earth) is an experiment onboard Chandrayaan-3 Mission for the study of spectro-polarimetric signatures of the habitable planet Earth in the near-infrared (NIR) wavelength range (1.0 - 1.7 µm). The spectro-polarimeter is the only scientific payload (experimental in nature) on the Propulsion Module (PM) of Chandrayaan-3 mission. The instrument is a compact and light-weight spectro-polarimeter with an Acousto-Optic Tunable Filter (AOTF) at its heart. The AOTF operates in the frequency range of 80 MHz to 135 MHz with a power of 0.5 - 2.0 Watts. The two output beams (e-beam and o-beam) from the AOTF are focused onto two InGaAs detectors (pixelated, 1D linear array) with the help of focusing optics. The primary (aperture) optics of ~ 2 mm diameter collects the NIR-light for input to the AOTF, defining the FOV of 2.6°. The payload is realized with a mass of 4.8 kg and a power of 25 Watts. In this manuscript, we highlight some of the ground-based results including the post-launch initial performance of the payload while orbiting around the Moon to observe Earth.

The Chandrayaan-2 Large Area Soft X-ray Spectrometer (CLASS) onboard the Chandraayaan-2 spacecraft around the Moon, has been remotely measuring the lunar X-ray fluorescence spectra since September, 2019. The primary objective of the experiment is to provide global maps of O, Mg, Al, Si at a resolution of 12.5 km/pix and of Ca, Ti and Fe at localized regions during enhanced solar activity, using the lunar X-ray fluorescence measurements in the 0.5 to 10 KeV range. CLASS is an array of swept charge devices (SCDs), a variant of X ray Charge Coupled Devices (CCDs) that provide good spectral resolution and large area. The quality of X-ray measurements strongly depends on accuracy of its calibration techniques. In this work, the results from the pre-launch calibration of the instrument that combines experimental measurements and simulations are described. The spectral redistribution function of the swept charge device is simulated using an augmented version of a previously developed charge transport model (Athiray et al., 2015). Response matrices built from these models are verified with in-flight data. We study the background in SCDs arising from particles in the lunar orbit over many months and identify the sources. We demonstrate the in-flight performance of the instrument that enables generation of direct elemental maps. Elemental abundances for a region in the farside highland and in the nearside western mare are derived demonstrating the method and the instrument capability of deriving the elemental abundances at different spatial scales and at different solar activity levels.

SSM onboard AstroSat is designed to monitor X-ray sky in the energy range 2.5–10 keV to detect and locate X-ray sources in outburst. SSM with its three almost identical 1D-proportional counters mounted on a rotating platform, scans the sky in step and stare mode of operation. It observes the X-ray sky and generates light curves for X-ray sources detected. Here, we discuss the positional calibration to carry out imaging with SSM. Onboard calibration of SSM has been carried out with Crab, the standard X-ray source. SSM observations of Crab are compared with that of MAXI on ISS for cross calibration of the instrument.

Chandrayaan- 2 Large Area Soft X-ray Spectrometer (CLASS) is an X-ray fluorescence spectrometer experiment aimed at mapping the abundances of major rock-forming elements on the lunar surface. The instrument consists of swept charge devices with a passive collimator, visible light blocking filters and signal processing electronics designed and built at U.R. Rao Satellite Centre, Indian Space Research Organisation. CLASS will be the largest collecting area spectrometer flown to the Moon, and thus is expected to map the abundances of lunar elements with a higher sensitivity than ever at soft X-ray energies.

Aditya-L1 mission will carry two high-spectral resolution X-ray spectrometers to study solar flares. The soft X-ray spectrometer will cover the energy range from 1 to 30 keV, while the hard X-ray spectrometer will cover from 10 to 150 keV. These two instruments together will provide opportunities to study the plasma parameters during solar flares as well as acceleration mechanisms of energetic particles during the flaring time.

We report the in-orbit performance of Scanning Sky Monitor (SSM) onboard AstroSat. The SSM operates in the energy range 2.5 to 10 keV and scans the sky to detect and locate transient X-ray sources. This information of any interesting phenomenon in the X-ray sky as observed by SSM is provided to the astronomical community for follow-up observations. Following the launch of AstroSat on 28th September, 2015, SSM was commissioned on October 12th, 2015. The first power ON of the instrument was with the standard X-ray source, Crab in the field-of-view. The first orbit data revealed the basic expected performance of one of the detectors of SSM, SSM1. Following this in the subsequent orbits, the other detectors were also powered ON to find them perform in good health. Quick checks of the data from the first few orbits revealed that the instrument performed with the expected angular resolution of 12’ \(\times \) 2.5\(^\circ \) and effective area in the energy range of interest. This paper discusses the instrument aspects along with few on-board results immediately after power ON.

Scanning Sky Monitor (SSM) onboard AstroSat is an Xray sky monitor in the soft X-ray band designed with a large field of view to detect and locate transient X-ray sources and alert the astronomical community about interesting phenomena in the X-ray sky. SSM comprises position sensitive proportional counters with 1D coded mask for imaging. There are three detector units mounted on a platform capable of rotation which helps covering about 50% of the sky in one full rotation. This paper discusses the elaborate details of the instrument and few immediate results from the instrument after launch.