Two crucial payloads were on the missing lander; two others are on the orbiter

Scientists at the Space Physics Laboratory (SPL) of the Vikram Sarabhai Space Centre (VSSC) at Thumba here are keeping their fingers crossed as the ISRO continues its efforts to establish contact with Vikram, the lander on the Chandrayaan-2 mission which has now been traced by the orbiter.

Of the 14 payloads aboard India’s second moon mission, four are from the SPL.

Of the four, two — RAMBHA-LM (Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere-Langmuir Probe) and ChaSTE (Chandra’s Surface Thermophysical Experiment) — are on the lander, which is believed to have crash-landed during Saturday’s soft-landing mission on the lunar south pole. RAMBHA, which is expected to provide valuable information on the lunar ionosphere, is made up of two components; one aboard the lander and the other, on the orbiter.

On the bright side for the SPL, its payload on the orbiter — CHACE-2 (short for Chandra’s Altitudinal Composition Explorer) — is functioning perfectly, SPL Director Radhika Ramachandran told The Hindu on Sunday.

“'The data from CHACE-2 is excellent. In fact, we have been taking observations and collecting data on the way, in the trans-lunar orbit and the lunar orbit as well. It is functioning perfectly,” Dr. Ramachandran said. CHACE-2 is designed to measure the composition of the lunar exosphere, and is an improvement on CHACE, which flew aboard the Moon Impact Probe (MIP) on the 2008 Chandrayaan-1 mission.

Ionosphere study

The second SPL payload aboard the Chandrayaan-2 orbiter, the RAMBHA-Dual Frequency Radio Science experiment (RAMBHA-DFRS), will study altitude variations of electron density in the moon’s ionosphere.

The hardware for this payload was developed by the ISRO Telemetry, Tracking and Command Network, Bengaluru.“'With this payload, we are only participating in the science part. We are using the DFRS communication channel with our ground receivers to calculate the ionospheric distribution,” the SPL Director said.