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Indian Lunar Lander

#11
Yazata Offline
Damn, I did stay up.

And the Indian rocket lifted off impressively, apparently successfully.

https://twitter.com/NASASpaceflight/stat...2496817152

From Earth orbit the Chandrayaan 2 will behave as that Israeli lander did, firing its engine each orbit to make each orbit more and more elliptical, until the apogee approaches the Moon's orbit and the Moon's gravitational sphere of influence where another burn inserts it into Lunar orbit. Requires some orbital mechanics to ensure that the vehicle reaches the top of its orbit right when the Moon is going by. Doing it this way is slower and more time consuming than the brute-force Apollo trip to the Moon, but doesn't require a giant rocket as capable as a Saturn 5. Estimated arrival at the Moon in September for the landing attempt.
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#12
C C Offline
(Jul 22, 2019 10:31 AM)Yazata Wrote: Damn, I did stay up.

And the Indian rocket lifted off impressively, apparently successfully.

https://twitter.com/NASASpaceflight/stat...2496817152

From Earth orbit the Chandrayaan 2 will behave as that Israeli lander did, firing its engine each orbit to make each orbit more and more elliptical, until the apogee approaches the Moon's orbit and the Moon's gravitational sphere of influence where another burn inserts it into Lunar orbit. Requires some orbital mechanics to ensure that the vehicle reaches the top of its orbit right when the Moon is going by. Doing it this way is slower and more time consuming than the brute-force Apollo trip to the Moon, but doesn't require a giant rocket as capable as a Saturn 5. Estimated arrival at the Moon in September for the landing attempt.

I didn't stay up. The flavor of "exhaust" from this rocket sort of reminds me a bit of the solid-propellant boosters of the old Space Shuttle.

Considering the (sometimes) heavy space probes that have been sent to other interplanetary bodies by slow-poke and slingshot backroad antics... I don't know why it initially slips my mind on occasion how launch vehicles avoid approaching 36-story buildings in size.
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#13
Yazata Offline
Chandrayaan 2's Vikram lander reportedly will make its Lunar landing attempt this Friday (US time) at about 1 PM PDT/4 PM EDT. That's 1:30 AM IST on Sept 7 in India.

Current status is that Vikram has separated from its Lunar Orbiter carrier and has conducted a burn to take its Lunar orbit closer to the Lunar surface in preparation for the landing attempt.
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#14
Yazata Offline
Livestream is on. So far, Vikram has been decelerating from Lunar orbit onto its landing trajectory everything is going well so far.

https://www.youtube.com/watch?v=2srV-bEi_DU

Edit: Now it doesn't look good.

The Vikram lander had a rough breaking phase where it decelerated from Lunar orbital velocity to a position roughly 2 km above the Lunar surface. Then it began a fine propulsive landing phase where it lowered itself from 2 km altitude to the Moon's surface. The data at that point seemed to show the Vikram lander was deviating from its planned trajectory and was descending too rapidly.

Then its data transmission rate back to Earth abruptly went to zero.

So it appears to have crashed during its final landing phase.

Photo from the ISRO mission control center showing the last parameters displayed before Vikram went dead.

Seems to show 48.1 m/s horizontal velocity, 59.0 m/s vertical velocity and 1.09 km altitude. Not sure if this was the last data received or just the last displayed on the big screen. I think that the green line on the descent trajectory plot shows Vikram's actual behavior, the red line what it should have been doing.

One of the ISRO guys on NSF said that it's "soul crushing" for those of them that have spent the better part of ten years working on this.


[Image: EDzunBuUwAAGbbA?format=jpg]
[Image: EDzunBuUwAAGbbA?format=jpg]

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#15
C C Offline
(Sep 6, 2019 09:19 PM)Yazata Wrote: ... So it appears to have crashed during its final landing phase...


That's surprising. Since in the wake of what happened to the Israeli moon probe, one might expect them to have doubled down on addressing all the items both known and unknown (picked up from the former crash) that could to wrong with their own landing.
Maybe they did, but that extra effort still wasn't enough -- at least they'd be exonerated from the overconfidence of routine evaluation and inspection (which is unbelievably thorough and complex itself).
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#16
Yazata Offline
India's ISRO (Indian Space Research Organization, their government space agency) is preparing for another try at landing a lander and rover on the Moon.

It's hard. Chandrayaan-2's lander crashed. Israel and Japan failed in recent years. There's several private American 'new space' companies hoping to do it in the next year or two as well. NASA is helping them with funding, in hopes of having several dissimilar alternatives for delivering stuff to the Lunar surface.

https://en.wikipedia.org/wiki/Chandrayaan-3

ISRO hopes to launch Chandrayaan-3 July 13, 2023. The landing attempt will hopefully come August 23, 2023.

Here it is all tucked into its payload fairing, rolling out to be mated to the rocket that will launch it.


[Image: F0QillXaQAAcbF5?format=jpg&name=900x900]
[Image: F0QillXaQAAcbF5?format=jpg&name=900x900]



Inside a payload integration building


[Image: F0QillbaQAAwHtt?format=jpg&name=900x900]
[Image: F0QillbaQAAwHtt?format=jpg&name=900x900]

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