Suramya's Blog : Welcome to my crazy life…

If you have been following my blog you know I love ISRO (Indian Space Research Organisation), they have been doing fantastic work at a fraction of the budget available to NASA and ESA. 3 days ago they made history again by becoming the 4th nation (after US, China and Russia) to successfully dock two satellites with each other. The mission was a Technology Demonstrator/Poof of Concept essential for India’s future space missions (which are quite ambitious). The mission parameters and Objectives were as follows:

SpaDeX mission is a cost-effective technology demonstrator mission for the demonstration of in-space docking using two small spacecraft launched by PSLV. This technology is essential for India’s space ambitions such as Indian on Moon, sample return from the Moon, the building and operation of Bharatiya Antariksh Station (BAS), etc. In-space docking technology is essential when multiple rocket launches are required to achieve common mission objectives. Through this mission, India is marching towards becoming the fourth country in the world to have space docking technology.

Objectives:

The primary objective of the SpaDeX mission is to develop and demonstrate the technology needed for rendezvous, docking, and undocking of two small spacecraft (SDX01, which is the Chaser, and SDX02, the Target, nominally) in a low-Earth circular orbit. Secondary objectives include:

• Demonstration of the transfer of electric power between the docked spacecraft, which is essential for future applications such as in-space robotics,
• Composite spacecraft control, and
• Payload operations after undocking.

ISRO is also doing good marketing and publicizing of its mission to get get more kids interested in Space and ISRO’s missions and towards that aim they released a video of the successful docking of the twin SpaDeX (Space Docking Experiment) spacecraft on YouTube:

Congrats again on a successful mission ISRO, we are all proud of you.

– Suramya

I really want this Sky Alarm, although that being said since I am in Bangalore 90% of the time it will happen that I would step outside and find the sky completely covered by Clouds.

Cool Space Thing happening. Go outside and look up (via XKCD)

Thinking about it a little more, it might be a fun project to create. The data can be pulled from some of the astronomy sites that track predictable events (eclipses/meteor showers etc). The tricky part would be to get information for events that are last min, such as Aurora sightings etc.

Something to think about for when I get some free time.

– Suramya

When we look at the photographs of the outer planets in our solar system, the planet Neptune stands out because of it’s striking blue color as shown in the photos taken by Voyager 2 back in 1989. (See below)

Photo of Neptune as taken by Voyager 2

In a new study just published in the Monthly Notices of the Royal Astronomical Society, researchers found that the color balance in Voyager was a little skewed that led to the planet appearing more blue than it actually is. Basically due to the way the images from Voyager were contrast enhanced to accentuate fainter features and better illustrate the atmospheric features of the planet the image released was bluer than what the planet actually looked like. They used observations of the planet taken from 1950 to 2016 along with data from the Hubble Space Telescope and the Very Large Telescope to create a more accurate representation of the planet’s color which is closer Uranus’s color than the vivid blue we are used to seeing. (See below)

Panels a and b show early images of the visible appearance of Uranus and Neptune reconstructed from Voyager 2 ISS images in 1986 and 1989, respectively, showing Uranus to be pale blue-green, and Neptune dark blue (PIA18182 and PIA01492, credit: NASA/JPL-Caltech).
Panels c and d show more recent reconstructions of the true colours of these planets, showing them to be more similarly coloured (credit: NASA/JPL-Caltech/Björn Jónsson)

From the Paper:

We present a quantitative analysis of the seasonal record of Uranus’s disc-averaged colour and photometric magnitude in Strömgren b and y filters (centred at 467 and 551 nm, respectively), recorded at the Lowell Observatory from 1950 to 2016, and supplemented with HST/WFC3 observations from 2016 to 2022. We find that the seasonal variations of magnitude can be explained by the lower abundance of methane at polar latitudes combined with a time-dependent increase of the reflectivity of the aerosol particles in layer near the methane condensation level at 1 – 2 bar. This increase in reflectivity is consistent with the addition of conservatively scattering particles to this layer, for which the modelled background haze particles are strongly absorbing at both blue and red wavelengths. We suggest that this additional component may come from a higher proportion of methane ice particles. We suggest that the increase in reflectivity of Uranus in both filters between the equinoxes in 1966 and 2007, noted by previous authors, might be related to Uranus’s distance from the Sun and the production rate of dark photochemical haze products. Finally, we find that although the visible colour of Uranus is less blue than Neptune, due to the increased aerosol thickness on Uranus, and this difference is greatest at Uranus’s solstices, it is much less significant than is commonly believed due to a long-standing misperception of Neptune’s ‘true’ colour. We describe how filter-imaging observations, such as those from Voyager-2/ISS and HST/WFC3, should be processed to yield accurate true colour representations.

It is facinating how much more there is to learn in the cosmos even about our own stellar neighbors never mind the whole wide universe out there with its infinite mysteries and grandeur.

Source: Neptune is more of a greenish blue than is commonly depicted

– Suramya

ISRO (Indian Space Research Organization) made a surprising announcement earlier this week about a new accomplishment by the Chandrayaan-3 Propulsion Module after the team managed to successfully return the propulsion module used by the spacecraft into a high orbit around Earth. This is a big deal and something only achieved by 3 countries before India (US, China and USSR).

This was not one of the planned missions for the module and was attempted when the team found that they still have over 100 kg of fuel in the PM available on the module for maneuvers. Its a credit to the precise planning and execution of the entire mission that the module still had extra fuel available for followup missions. So the orbit was modified over the course of a few months to move to an Earth orbit at about 1.54 lakhs kms (154,000 kms) allowing the module to complete an orbit every 13 days.

In order to continue SHAPE payload for Earth observation, it was decided to re-orbit the PM to a suitable Earth orbit.This mission plan was worked out considering the collision avoidance such as preventing the PM from crashing on to the Moon’s surface or entering into the Earth’s GEO belt at 36000 km and orbits below that. Considering the estimated fuel availability and the safety to GEO spacecrafts, the optimal Earth return trajectory was designed for October 2023 month.

First maneuver was performed on October 9, 2023 to raise apolune altitude to 5112 km from 150 km thus, increasing the period of orbit from 2.1 hrs to 7.2 hrs. Later, considering the estimate of available propellant, the second maneuver plan was revised to target an Earth orbit of 1.8 lakhs x 3.8 lakhs km. The Trans-Earthinjection (TEI)maneuver was performed on October 13, 2023. In thepost-TEI maneuver realized orbit, propulsion module made four Moon fly-bys before departing Moon SOI on November 10. Currently, propulsion module is orbiting Earth and crossedits first perigee on November 22nd with an altitude of 1.54 lakhs km. The orbit period is nearly 13 days with 27 deg inclination. The perigee and apogee altitude vary during its trajectory and the predicted minimum perigee altitude is 1.15 lakhs km. Hence as per current orbit prediction, there is no threats of close approach with any operational Earth orbiting satellites.

This test was a good way to prepare for future lunar missions where one of the mission parameters would be to bring back samples from the Moon to earth for study. The module’s expected lifetime was about 3 months and its already past that and still going on. Looking forward to finding out what other additional experiments we can run on it.

– Suramya

Source: Arstechnica.com: India reveals that it has returned lunar spacecraft to Earth orbit