Suramya's Blog : Welcome to my crazy life…

India’s space program has been very active over the past few years and following the success of Chandrayaan-3 & Aditya missions, India became the 4th nation to dock two satellites in space earlier this month. The next major mission ISRO is planning is the Gaganyaan mission. Gaganyaan (“Orbital Vehicle”) is a crewed orbital spacecraft intended to be the basis of the Indian Human Spaceflight Programme. The first of three flight tests prior to the inaugural of crewed mission is planned for December 2025. But before that there are multiple tests & launches planned for testing the equipment and earlier this week, ISRO successfully completed its first Integrated Air Drop Test for Gaganyaan Missions. An air drop test recreates the final leg of a spacecraft’s journey back to Earth by dropping the spacecraft from a height to test various systems under different circumstances.

In Gaganyaan missions, parachute-based Deceleration system is employed during terminal phase of Crew Module (CM) descent to reduce the touchdown velocity of Crew Module to an acceptable limit for safe landing on sea. The parachute system and its layout, for IADT, was same as that of Gaganyaan missions. It comprised of four types of parachutes viz. Apex Cover Separation (ACS) (Ø 2.5 m – 2 nos), Drogue (Ø5.8 m – 2nos), Pilot (Ø3.4 m – 3 nos.) and Main parachutes (Ø 25 m – 3nos.).

In IADT-01, the simulated Crew module (~4.8 t) with Parachute system was released from an altitude of about 3 km using Indian Air Force’s Chinook Heavy lift helicopter. The deceleration system initiation began with firing of ACS Mortar which deploys the Ø2.5 m ACS parachutes, which is followed by the separation of Apex cover. The deployed ACS parachutes then decelerated the Apex cover and prevented it from re-contacting the descending simulated CM during the test. The Ø5.8 m Drogue parachutes were then deployed using Drogue Mortar, which provided first stage deceleration to the simulated crew module. After first stage deceleration, the Drogue parachutes were released using pyro-based parachute releasers. This was followed by firing of three Pilot Mortars, which ejected and deployed the Ø3.4 m Pilot parachutes., which then independently extracted and deployed the three Main parachutes of Ø25 m diameter.

Now that we have successfully cleared the first integrated drop test, work on the second test mission in the third quarter of 2025 is moving at a fast pace. This second test will simulate an abort scenario to demo the crew escape system for the Gaganyaan. After this, in Q4 2025 the first uncrewed mission Gaganyaan-1 will take place, which will carry an unpressurised crew module to space and back. Two more uncrewed test flights are planned in early 2026 for additional testing of equipment which will be followed by a crewed mission in Q3/Q4 2026.

Looking forward to more successful missions by ISRO.

– Suramay

ISRO’s successfully tested the latest version of their Reusable launch vehicle (RLV) technology through the RLV LEX-02 landing experiment. The Lander called Pushpak (RLV-TD) landed autonomously with precision on the runway after being released from an off-nominal position.

RLV-LEX-02/Pushpak landing autonomously (Pic Credit: ISRO)

The winged vehicle, called Pushpak, was lifted by an Indian Airforce Chinook helicopter and was released from 4.5 km altitude. After release at a distance of 4 km from the runway, Pushpak autonomously approached the runway along with cross-range corrections. It landed precisely on the runway and came to a halt using its brake parachute, landing gear brakes and nose wheel steering system.

This mission successfully simulated the approach and high-speed landing conditions of RLV returning from space. With this second mission, ISRO has re-validated the indigenously developed technologies in the areas of navigation, control systems, landing gear and deceleration systems essential for performing a high-speed autonomous landing of a space-returning vehicle. The winged body and all flight systems used in RLV-LEX-01 were reused in the RLV-LEX-02 mission after due certification/clearances. Hence reuse capability of flight hardware and flight systems is also demonstrated in this mission. Based on the observations from RLV-LEX-01, the airframe structure and landing gear were strengthened to tolerate higher landing loads.

This was the second successful test of the system and the winged body and all flight systems used in RLV-LEX-01 were reused in the RLV-LEX-02 demonstrating the reuse capability of flight hardware and flight systems. This system is essential to the creation and use of RLV technology in future launches which will enable us to reduce the cost of the launches going forward. This will also allow us to increase the number of launches and the payload we can put in orbit in a given time period. Another key point to note is that all the technology used in the craft was developed indigenously in India.

Source: ISRO achieves yet another success in the RLV Landing Experiment

– Suramya

When people talk about strong materials that can be used to make durable satellites wood is nowhere even close to being considered. I mean come on, the image people (including me) have in their mind of wood is that it is something not too strong and for the most part is not durable. However, NASA and the Japan Aerospace Exploration Agency (JAXA) are set to prove that is not the case and are planning to launch the world’s first wooden satellite into space. Yes, you did read that correctly; they are planning to use wood to make a satellite instead of Stainless Steel or titanium which will make the process a lot more sustainable. LignoSat is a coffee mug-size satellite made from magnolia wood and will be launched into orbit sometime during the Summer of 2024. Wood has an advantage over other materials in that it will burn up into ash during reentry into the atmosphere without releasing harmful chemicals into the atmosphere (which is what happens when Steel or Titanium reenters the atmosphere and burns up).

To verify the feasibility of using the material Kyoto University researchers sent samples of magnolia, cherry and birch up to the International Space Station and exposed it to space for 10 months, after which tests were run against the samples and when they confirmed that there was no decomposition or deformation in the samples it gave them confidence to move ahead with the project. LignoSat will be made using the wood from magnolia trees primarily because of the relative ease of working with it, dimensional stability, and overall strength as compared to the other candidates.

Another advantage of a wooden satellite is that it is less reflective than other materials which means that it would reduce the amount of ambient light pollution that astronomers have been complaining about over the past few years. Especially since the Starlink low orbit satellites were launched. Wood is also easier to grow so the overall cost might be lower.

One potential problem with this approach would be that it will require a lot of wood which would mean that forests would be logged offsetting the environmental gains made by using wood. Assuming the test is successful, we can look forward to using wood in more places instead of non eco friendly materials. But I doubt that it would replace the traditional materials completely.

– Suramya

Source: Wood Working Network: Japan set to launch first wood satellite