Pradeep's Space Newsletter #53
Chandrayaan 3 and Interview with ISRO Chairman
Chandrayaan 3
Chandrayaan 3 lifted-off from the Second Launch Pad at Sriharikota on 14 July 2023. The spacecraft was placed in an eccentric geocentric transfer-like orbit. Following the launch, Chandrayaan 3 performed two of the five planned Earth Bound Maneuvers (EBM).
Orbit achieved at Launch: 36,500 km x 170 km
Orbit achieved after First EBM: 41,762 km x 173 km
Orbit achieved after Perigee Raising Burn: 41,603 km x 226 km
Orbit achieved after Second EBM: 51,400 km x 228 km
ISRO announced that it expects to do the next burn on 20 July, after they analyse the data from the second EBM. It has announced on the home page to follow ISRO on Twitter for future updates.
Screen grab from the Chandrayaan 3 launch of the spacecraft separation from LVM3-M4. Image Credit: ISRO
The ISRO sub-Reddit captures pictures and videos from the launch - venting of the C25 stage post-launch, captured from Australia, capture of the S200 solid booster separation captured from Chennai, view from the Launch Gallery at Sriharikota (another view, another view, another view with the crackles, another view, another view, another view), and from an Indigo flight from Chennai.
Jatan Mehta has more detailed updates on a weekly cadence related to Chandrayaan 3.
Interview with ISRO Chairman
User r/Ohsin on the ISRO sub-Reddit has shared the highlights of the video in text form here, quoted below:
On dust blow-back issue and removal of fifth central engine on Chandrayaan 2: Two peripheral engines will immediately shutdown upon touchdown minimizing blow-back, landing with single engine not possible due to lander mass increase. There will be some blow-back but trading it off with better chances at landing.
Three TT&C antennas on lander for better data rate and redundancy. LIVE view might be possible during landing attempt.
Laser Doppler Velocimeter sensor was not included on CY2 as they couldn't procure it. Developed it in India for CY3 (They earlier said it didn't perform well during ground tests for CY2).
Open to ideas like performing a hop with lander post primary mission but onboard guidance algorithm is not suitable for it and they'd have to upload it from ground.
Propulsion Module will not function as science data relay and they'll use CY2 orbiter for it. SHAPE payload has mission life of 4 to 6 months but could last more.
Relevant payload papers for SHAPE, LDV etc will be released after launch.
On changes to lander and rover: Better contingency management and battery capacity for rover increased from 5 Ah to 10 Ah
Rover range and speed same as earlier. Lander has two additional cameras in rear for better FOV.
On prospects of Chandrayaan-2 FAC report release: What happened is sufficiently explained in official statements..
Checquered markers on ramps are reference for distance measurements and scaling purpose.
Avoided answering question on CY1 water discovery controversy.
ISRO's outreach programme and social media handling is just two or three people and few volunteers. Keeping the quiet approach so as to not put pressure on teams.
For Shukrayaan or Venus Orbiter Mission payload definition, project report with costs etc. submitted to Govt. and awaiting the approval. (Shukrayaan name btw came from PRL abstract. [PDF])
On MOM-2: Not seeing much scientific interest about it but continuing to engage academia but so far proposals are not satisfactory.
On NGLV timeline: Everything hinges on throttleable LOX-Methane engine for which Preliminary Design Document is readyt. Development time of 10 years for NGLV would be too long and doesn't serve their purpose.
Somanath points out ADMIRE was proposed by him when he was at VSSC but couldn't get approval for it by department and Govt. so converted the proposal into Test Vehicle for Gaganyaan. TV can be turned into ADMIRE with addition of legs and control surfaces just awaiting Govt. approval.
On GSLV Mk III to LVM3 name change: Was necessary to differentiate it from GSLV Mk II as they do not share heritage. Faced launch insurance related issues as well due to bad reputation of GSLV Mk II.
Btw, RHU was planned to be flown on TDS but which TDS it was not clear and still isn't, don't know where RTG speculation came in from.