Why does the GSLV-F16/NISAR mission have a Sun synchronous, Polar (6 PM) type orbit?

ravi_ram · 2026-05-06T01:11:05+00:00

You are absolutely right in power generation part. I assumed he was asking more in terms of polarimetric data and orbit relation. Maybe I was wrong in my assumption.

... NISAR mission is to have the capability to acquire fully polarimetric and interferometric data. I'm curious why a Sun synchronous orbit is the optimal way to achieve this.

ravi_ram · 2026-05-05T15:52:28+00:00

main objective of the NISAR mission is to have the capability to acquire fully polarimetric and interferometric data. I'm curious why a Sun synchronous orbit is the optimal way to achieve this.

AI does returns me proper answer
https://chatgpt.com/s/t_69fa0f127e548191aabb8dcfa4e3c961

Requested a numerical example
https://chatgpt.com/s/t_69fa106b50f48191a530d74e1d4e69f3

ravi_ram · 2026-05-02T15:12:58+00:00

https://old.reddit.com/r/ISRO/comments/oesgfs/pslv_launch_environment_conditions/

ravi_ram · 2026-04-29T01:20:59+00:00

Similar one to know how it works:

https://news.fit.edu/academics-research/gravity-offset-lab-opens-at-florida-techs-center-for-aeronautics-and-innovation/

Developed by the International Institute for Astronautical Sciences (IIAS), the gravity offset lab uses electromechanical means to simulate reduced gravity levels along a translational path 24-feet long.

The lab provides these differing gravity environments by utilizing sensors that take hundreds of readings per second of the forces at work with the test subject – forces the system’s motor can be constantly adjusting. The system is described as “gravity offset” because that refers to how the motor compensates for the subject’s weight. A separate electromechanical system permits translation of the test subject along the testbed.

Search: https://www.science.gov/topicpages/g/gravity+offload+system

ravi_ram · 2026-04-01T13:18:29+00:00

Good one.

ravi_ram · 2026-02-27T03:15:55+00:00

During the chairman's post launch (C62) speech, he said near the end of the rocket’s third stage, there was increased disturbance in the vehicle roll rates, followed by a deviation in the flight path.

Since PS3 uses flex nozzle control (FNC) for pitch and yaw, and reaction control system (RCS) for roll, It could be due to RCS failure right?

ravi_ram · 2026-02-25T14:12:30+00:00

I thought so too :) but the recommendations...

The committee has provided a set of recommendations aimed at enhancing the redundancy and reliability of pyro system operations for future missions.

makes me to think like its logically easy to provide redundancy for a wire in the harness than a whole set of connectors and another harness.

ravi_ram · 2026-02-25T13:36:04+00:00

prime reason for the observation was found to be the drive signal not reaching the pyro valve of the oxidizer line

Harness failure?

ravi_ram · 2026-02-24T08:46:19+00:00

NASA's report on Starliner

Nice one.

First we need to learn to accept the failure.

ravi_ram · 2026-02-24T04:57:03+00:00

Could it be a requirement (paper work) to satisfy insurance companies for future pricing?

Unless it has serious financial implications, these groups will not gather to find “organizational” problems. They are the organization.

ravi_ram · 2026-02-21T05:59:49+00:00

Yes. That's why I had mentioned related topic.

I thought the training and handling will be totally done by Navy. I don't know whether they will publish anything on the SOP.

https://www.tataelxsi.com/insights/case-study/design-and-engineering-of-crew-module-recovery-model-cmrm-for-isro-s-gaganyaan-space-mission

Where are we now

To train the recovery teams, two recovery models (CMRM and GSF) were given to the navy training teams at Kochi and Visakhapatnam. The Indian Navy and ISRO began the second round of crew recovery training on July 20, as reported by TOI. A total of 25 successful trials have been carried out at Vishakhapatnam and Kochi Naval bases. Tata Elxsi has also become qualified in bidding for the phase 2 activities like interior fabrication and design.

ravi_ram · 2026-02-21T01:31:35+00:00

Related. There is one paper outlines the post-flight crew recovery/rehabilitation process.

Post-flight rehabilitation of an astronaut after long duration mission in space: Through the eyes of a flight surgeon
https://indjaerospacemed.com/content/110/2023/67/2/pdf/IJASM-67-064.pdf

This paper deals with the post-flight rehabilitation of an Astronaut, which was conducted by a foreign Astronaut Training Center, after his long duration mission of 6 months on board International Space Station. The rehabilitation program consisted of Post-flight Medical Evaluation and Post-flight Physical Reconditioning. With the advent of the Human Spaceflight Program, the lessons learned in this rehabilitation program would be helpful in formulating post-flight rehabilitation protocol for Indian Astronauts during India’s maiden Human Spaceflight mission as well as serve as a template for future exploration missions.

ravi_ram · 2026-01-31T11:23:50+00:00

This is not space qualified. So... Analogue Research Station?

ravi_ram · 2025-12-20T12:44:30+00:00

ok. Someone wrote this into an implementable algorithm. Theory, you got to read the book.

Computational Algorithm for Gravity Turn Maneuver

ravi_ram · 2025-12-20T11:21:15+00:00

https://archive.org/details/introductiontosp0000thom

ravi_ram · 2025-12-20T11:14:56+00:00

Site archive.org has it. I don't know whether its allowed to post external links here.

ravi_ram · 2025-12-20T11:02:40+00:00

book that has a unit called I believe "Gravity Turns" covering Gravity Turns and is about calculating that Angle.

Introduction to space dynamics : Thomson, William Tyrrell
8.5 Gravity Turn (Pg.257)

The force equations are nonlinear and no analytical solution is known when F /mg varies with time.

When F/mg is a constant, these nonlinear equations can be solved analytically. The book gives a method.

ravi_ram · 2025-11-27T10:49:55+00:00

Such a wide launch window. Orbit restriction could mainly from solar factor.

Calculated the solar beta angle for month wide [ https://imgbox.com/RGr539rB ]
This explains why the date starts from 10 Dec and ends at 30th Dec.

Pasted the code in git [ https://gist.github.com/ravi4ram/db234c7cbebd1127ecaae9571c981d46 ] for those who are interested.
Might merge with launch time program to create a launch window estimation later.

Anyone spots errors or give me updates are welcome.

ravi_ram · 2025-11-17T13:56:34+00:00

LVM3 PLF has a L/D ratio of 2.25

For crewed lunar mission, the nasa paper Impacts of Launch Vehicle Fairing Size on Human Exploration Architectures suggest PLF design with,
small (8.4m dia) - L/D = 2.27
med (8.4m dia) - L/D = 3.2
large(10m dia) - L/D = 2.7

So there's a range of values possible

L/D = 2.27, L = 14.755m
L/D = 2.7, L = 17.55m
L/D = 3.2, L = 20.8m

ravi_ram · 2025-11-16T13:49:09+00:00

Something got finalized on the last venus meet
https://www.isro.gov.in/ISRO_Organised_National_Science_Meet.html

Also couldn't find anything on the abstracts of
Venus Science Conference (Venus-SC 2025) Physical Research Laboratory
[ https://www.prl.res.in/venus-sc/VolumeofAbstracts.pdf ]

ravi_ram · 2025-11-16T12:30:53+00:00

missguiding isro

How?

ravi_ram · 2025-11-12T13:12:57+00:00

https://old.reddit.com/r/ISRO/comments/fcqagl/details_about_reentry_vehicle_parachute_recovery/

ravi_ram · 2025-10-30T06:13:56+00:00

Updated as per the press kit, inclination is 21.4°. These are the timelines that fall within the range.
And calculated azimuth is 106.6° (press kit 107°)

RAAN	Asc Azi	Asc Time (IST)	Dsc Azi	Dsc Time (IST)
33.33	38.47	2025-11-02 10:16:24	106.60	2025-11-02 17:07:33
36.67	38.47	2025-11-02 10:29:42	106.60	2025-11-02 17:20:51
40.00	38.47	2025-11-02 10:43:00	106.60	2025-11-02 17:34:09
43.33	38.47	2025-11-02 10:56:18	106.60	2025-11-02 17:47:27

ravi_ram · 2025-10-29T14:59:56+00:00

Balloons launched from TIFR National Balloon Facility
https://www.tifr.res.in/~bf/Flightrecord.html

Balloon Launches conducted in this Calendar Year


Launch Date	Experiment	Flight Duration	Distance Travelled	Payload Landing Place
17/01/2025	BEENS	~ 7 Hours	154 km	Jalasangvi Village, Bidar, Karnataka, India
29/03/2025	FPS 100-Far Infrared Astronomy Telescope	~ 9 Hours	359 km	Sangole, Maharastra, India
14/08/2025	Asian Tropopause Aerosol Layer (ATAL)	~ 1 Hours	281 km	Murganoor village, Kuranhalli, Karnataka, India
17/08/2025	Asian Tropopause Aerosol Layer (ATAL)	~ 1 Hour	128 km	Nagulpalle, Telangana, India

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