Yeah, I did. SpaceX tried retrieving the lower stages using parachute. I was speaking of the upper stage Obviously, human capsules with roughly the same weight as inert upper stages have been recovered accurately using parachutes. Our care module for example was 3.7 tons.JayS wrote: IR, did you check the links I posted for you in Int'l Aerospace thread regarding this..? Seems SpaceX tried parachute recovery and rejected it.
, jingos can replace number 91 in sbe91 with numbers 19 or 20 or 21 or 22 and see the fun
Where ?jaysimha wrote:HUMAN SPACEFLIGHT cancelled....
http://www.indiabudget.gov.in/ub2018-19/eb/sbe91.pdf
Notes on Demands for Grants, 2018-2019
No. 91
Department of Space
DEPARTMENT OF SPACE
DEMAND NO. 91
Department of Space,
in the above URL,
Instrument Characteristics
The L-band and S-band radars are being designed to work independently or together. The L-band hardware is being developed by JPL and its industrial partners, and the S-band electronics portion by ISRO. The feed apertures at L and S band are built by JPL and ISRO respectively as well, phase-matched to their respective electronics and cabling. In this sense, each radar will be a self-contained instrument up to the radiated energy from the feed aperture. Thereafter, both will share the same reflector, with a nearly identical optical prescription (F/D=0.75). Because a distributed feed on a reflector-feed antenna has a single focus, much of the radiated and received energy is away from the focus. Since S-band wavelength is 2.5 times shorter than L-band, yet the feed is the same length to achieve identical swath coverage, the S-band system has greater deviations from the focus. Thus the design has been iterated to derive the best offset, tilt, and phasing of each radar to balance the performance across the two systems. This analysis has been done independently by the JPL and ISRO teams, then cross-compared to validate.
For the radars to operate together as a dual-frequency system, it is necessary to share a 10 MHz oscillator and pulse timing signals to synchronize transmit events from each radar, and to minimize phase inconsistencies across systems. The development units at JPL and ISRO have been fabricated, and the first interface verification test was conducted in December 2016. This paper will show some examples from this successful test.
Another concern is the coupling between the feed apertures. In the current design, the two apertures would be mechanically and electrically separated, with manageable coupling. Presently dual-frequency operations are planned only over Indian science investigation sites, but other areas would be possible. A compatibility test between the engineering model apertures is planned for early 2017; this paper will report on the findings of that test.
To meet the requirement of a swath over 240 km in width at fine resolution, using full polarimetry where needed, it was necessary to implement a scan-on-receive system that allows for digital tracking of multiple pulses on the feed at any one time [3]. This “SweepSAR” implementation is done using individually addressable Transmit Receive (T/R) modules at both L and S-band. L-band has 12 T/R modules per polarization and S-band has 24. On transmit, all are activated to illuminate the entire feed, which creates a narrow illumination pattern on the reflector in elevation. This in turn creates a broad illumination pattern on the ground. On receive, the echo, which is localized in space and time, reflects off the full area of the reflector, giving maximal signal. As the echo sweeps across the ground and propagates back to space, it is reflected and sweeps across the feed. Each receive channel can track the echo individually, but rather than recording each channel separately and recording all the data, the radars combine three adjacent T/R modules to form a beam that allows a continuous swath to be generated on orbit. This saves data rate to the ground, but requires precise real-time relative calibration of the electronics to ensure the summation of channels is done optimally. Filtering, decimation, calibration estimation, and combining are done in a set of FPGAs or ASICs on each radar
Current Status
The NISAR project successfully completed its Preliminary Design Review in June 2016 and has now entered the Development Phase of the project lifecycle. Engineering model hardware exist for all the major L-band technology components, including the T/R module, first stage digital processor, second-stage digital combiner, control units, and frequency synthesizers. These subsystems have been tested over temperature, and are currently in revision for the Flight Model units.
Several key development partnerships on the NASA side are now in place. The 12-m reflector will be developed by Astro Aerospace - Northrop Grumman. The Solid State Recorder will be developed by Airbus Defence and Space, and the JPL-designed L-band transmit receive modules will be manufactured by The Boeing Corporation. In December 2016, ISRO brought development model interface elements of the S-band radar to JPL for interface testing. This successful test was the first joint ISRO and NASA hardware activity on this project. An antenna aperture compatibility test is planned for 2017 at ISRO.
Can someone throw light on the 14 days only sunlight?http://www.newindianexpress.com/states/ ... 75023.html
Another important factor is that when the Lander makes the touchdown on the pre-determined site near south pole of lunar surface, there should be sunlight. In a month, moon sees sunlight for only 14 days,” Sivan said.
..
He said the initial lifespan of the mission will be for 14 days. “The rover will be carrying out its functions using solar power. So, we look to achieve our mission objectives in these first 14 days and the rover will go into passive mode during night phase which is about 15 days. We hope the solar panels in the rover will get recharged once the sunlight is back, but we are not sure about it since this is our first attempt to land on lunar surface. We are hopeful and conducting relevant tests to extend the life of the mission.”
Indranil ji,Indranil wrote:Well Haridas ji,
We both got it wrong. I should have stuck to my original guess of 2 mtr diameter. But I would have never guessed this stage ratios: S85 +S7 +S4. I wonder what part our geography plays in choosing such a large first stage. The S85 is made of 3 segments which are roughly 35 +35+15 tons. S7 probably comes from PSLV's 3 stage. But S4 will be a completely new stage or from our 2 mtr dia ballistic missiles. They do say "utilizing existing technologies and infrastructure". If yes, that S4 stage is pertinent to our discussion on modified Agni 3.
Click on the image for higher resolution.
Hope this is useful as for many this may not be entirely clear.SaiK wrote:
Can someone throw light on the 14 days only sunlight?
Log ago I evaluated GSLV MK2 with current engine but larger fuel. Found that 12.5 ton was near optimal fuel confign. 15 ton will not increase much payload capabelity.Varoon Shekhar wrote:Any update on the launch of the GSLV Mark 2, with GSAT 6A? There is an upgraded cryogenic engine/stage on the vehicle, upgraded from C-12 to C-15.
Varoon Shekhar wrote:First heard this from Spaceflight Now. Pretty reliable site, am assuming they are accurate. Another site Spaceflight.com, a little less credible, says that the launch will be on March 1st.
"India’s Geosynchronous Satellite Launch Vehicle Mk. 2 (GSLV Mk.2), flying on the GSLV-F08 mission, will launch the GSAT 6A satellite to provide S-band communications and demonstrate the performance of a 6-meter unfurlable antenna and other network technologies for future satellite-based mobile communications applications. The GSLV Mk.2 will fly with an upgraded Indian-built cryogenic upper stage. Delayed from January and February."
You are right Haridas sir. Varoon ji, they are increasing the thrust from 7.5 tons to 9.5 tons. Propellant mass AFAIK is going to stay the same.Haridas wrote:^^^ I expect the upgraded stage to use engine tweaked to even higher thrust, that is crucial for increasing payload capebelity.
Long time ago, India in collaboration with Rus changed the isro Russian cryo stage from flat rated thrust to peaking the thrust initially to get out of gravity loss early. That became the standard for all GSLV Mk1 launches. Now with brandnew C25 under its belt, isro can more confidently improve the CUSP thrust with low hanging fruits.
Jmt.
IMO Launch would be highly impossible in April. There would probably be two GSLV launches before the Chandrayaan-2 launch. Reason lies with the spacecraft still being in assembly and testing still going on (they were about to test the lander). Considering all these delays, it would be reasonable to assume that the launch could happen only in the 3rd quarter, or could even move to the 4th quarter of the year.Varoon Shekhar wrote:^
Prasanna, do you know if there's a good chance that the Chandrayaan-2 moon mission will be launched in April, or with the delays in the other launches, is it more likely for November( which is the next date that a moon mission will be more efficient). Is the April launch off for now?
From ISRO's 2017-18 annual-report ()Link:sohamn wrote:Not much updates on SCE 200 lately, last year had heard some contract with Ukraine regarding testing - but haven't seen any update thereafter. Sometimes I wonder, given how much financial troubles Ukraine is in, why can't be buy few semi-cryo engine tech from them? Same goes for marine turbine tech.
From interview with Dr Sivan (Link)The semi-cryogenic Project envisages the design and development of a 2000 kN semi-cryogenic engine for a future heavy-lift Launch Vehicle. The semi-cryo engine development moved from design and hardware realisation phase to testing and verification phase. Major thrust was provided towards hardware roll out from industry. Most of the hardware are in the advanced stage of completion. 12 types of Flow control valves required for power head test have been realised and testing is in progress. As part of the Turbo-pump development, Low Pressure Oxidizer Turbopump (LPOT-D2) and Main Oxidizer Pump (MOP-D1) have been realised and cold flow test conducted for nominal operating conditions. Qualification of engine turbo-pump systems such as bearing and seals are in progress. Semi-cryo engine Thrust Chamber Pre-Burner, injector head and heat exchanger were realised for mock up engine for engine integration trials. Integrated engine test facility for testing the engine is under construction.
For the semi-cryogenic launch vehicle, the engine development is going on. Some critical [sub-systems] are getting fabricated or tested. Our target is to test fly it sometime in 2019.
According to media reports, the Indian Space Research Organisation (ISRO) is likely to launch its second lunar mission, called Chandrayaan-2, to the moon's South Pole only in October. Earlier, the mission was slated to be launched in April, with ISRO chairman K Sivan stating that the window for the mission launch will be open until November. According to media reports, the Indian Space Research Organisation (ISRO) is likely to launch its second lunar mission, called Chandrayaan-2, to the moon's South Pole only in October. Earlier, the mission was slated to be launched in April, with ISRO chairman K Sivan stating that the window for the mission launch will be open until November. An ISRO official said that several tests were yet to be done, adding that further delays cannot be ruled out if systems were still not in place by October. "We do not want to be in a hurry," he said. Interestingly, if the mission does launch in October, it will coincide with the 10th anniversary of Chandrayaan-1, India's first lunar mission.
