ISRO's Mars Orbiter Mission

[Tech Support]

some of the scientists gave some truly moving speeches (one man who had been with ISRO since the 60's was in tears as he congratulated the team)

[Zaran]

I was able to record the launch from T-1 Minute to T+3 Minutes before my DVR locked up and crashed on me, if you missed the launch you can watch the replay here:

[Tech Support]

I was able to record the launch from T-1 Minute to T+3 Minutes before my DVR locked up and crashed on me, if you missed the launch you can watch the replay here:

Thank you !

[Tommygun]

I watched the live feed. Did I hear the announcer say that the fairings (I think he called them heat shields) where jettisoned about 200 seconds into the flight?

Are they released that early?

[Kryten]

Sounds about right. PSLV is mostly solids, so it leaves the atmosphere pretty rapidly.

[NASAFanboy]

I'm wish the best for India and their orbiter mission. We need to see more nations taking a interest in Mars exploration/colonization, and maybe, someday, in..let's say, the 2060's, we'll do it.

[Meithan]

Every successful rocket launch for non-military purposes fills my heart with joy. And this one's specially important since it's India's largest undertaking so far -- and not a modest one! Congratulations to all Indian engineers and scientists! I truly hope the rest of the mission goes as well as the launch and orbit insertion.

[Sochin]

A harty good luck to them, lets hope they dont rope in the martians into setting up a tech support call centre!

[Drunken Hobo]

Hooray, good to see some positive comments about this. Had the misfortunte of reading the BBC comments and it's full of "We give aid to India & now they're spending my tax money on rockets!!1".

For some reason people think spending money on science is regressive behaviour...

Hope the satellite arrives at Mars safe & well. It's a relatively inexpensive project, and often they don't go too well. Though if it and MAVEN succeed, we'll have 5 satellites around Mars. Starting to get crowded up there.

[Mr Shifty]

Congrats to the ISRO on a successful launch! We'll have to come back on November 30 to celebrate a successful Earth escape.

Edited November 5, 2013 by Mr Shifty

[nhnifong]

Woop! Go India!

[magnemoe]

Does it use an ion engine? noticed that it needed lots of orbit around earth to reach escape speed.

[Krevsin]

Excellent, more national space agencies paying a visit to the red planet. Always a good thing.

[Mistake Not…]

Does it use an ion engine? noticed that it needed lots of orbit around earth to reach escape speed.

Low-thrust burns at each periapsis building up into a departure trajectory, taking advantage of our friend the Oberth effect. Simple but surprisingly informative PDF here.

(Pretty much the same technique I recently used in getting a giant lag-monster to Moho!)

[Mr Shifty]

Does it use an ion engine? noticed that it needed lots of orbit around earth to reach escape speed.

It's a chemical engine: monomethylhydrazine and dinitrogren tetroxide. It's using orbit pumping to save delta-V via the Oberth effect. The spacecraft engine has to be used for both ejection and insertion (no aerobrake.)

[magnemoe]

Low-thrust burns at each periapsis building up into a departure trajectory, taking advantage of our friend the Oberth effect. Simple but surprisingly informative PDF here.

(Pretty much the same technique I recently used in getting a giant lag-monster to Moho!)

I also used on the Beast, the 1500 ton / 759 parts Jool lander, however here the issue was mostly that the TWR was to low to do the burn in one go.

[Tommygun]

Low-thrust burns at each periapsis building up into a departure trajectory, taking advantage of our friend the Oberth effect. Simple but surprisingly informative PDF here.

(Pretty much the same technique I recently used in getting a giant lag-monster to Moho!)

That pdf image file looks disturbingly like the map view in KSP.

[Superluminaut]

Next year when mars gets its new arrivals, its gonna be exciting.

[Tech Support]

Scott Manly's latest deep space network news, he starts with the MOM mission and continues on to news on the next KSP update and other stuff.....

[Camacha]

hello, everyone ! I had the privilege of seeing the damn thing go up ! the launch was entirely successful and the satellite is now in earth orbit, the appo. will be raised gradually and in December, the satellite will begin its voyage to Mars.

I was wondering about this gradual raising of the apoapsis. I understand this is done because of the alternative launcher that does not have the capability of putting the probe directly on track. However, KSP has taught me that more gradual burns (so over a number of passes too) are less efficient due to gravity drag and other phenomena.

Does anyone know how these two combine and why the craft is not boosted into its Mars orbit after the first pass?

[Kryten]

It's because the thrust of the engine on the craft is rather low-it's going to have to burn for something like half an hour in total to do the TMI burn. If they attempted to do this as a single burn, an enormous amount of fuel would be wasted because only a small portion of the burn would have been done near periapsis.

[PakledHostage]

Does anyone know how these two combine and why the craft is not boosted into its Mars orbit after the first pass?

What they are doing is a series of small perigee kicks to add orbital energy to the spacecraft, in preparation for the final ejection burn that will send it on its way to Mars in December. The perigee kicks take advantage of the Oberth effect to increase the efficiency of the burns. NASA's LADEE probe used the same procedure to reach the moon.

I have actually been thinking of hosting a new efficiency challenge, along the lines of my earlier "Minimum delta-V to the Mun" challenge that was lost when the forum database was corrupted last spring. During the old challenge, people tried techniques such as perigee kicks with some success.

Edit: Ninja'd by Kryten

Edited November 7, 2013 by PakledHostage

[Superluminaut]

I was wondering about this gradual raising of the apoapsis. I understand this is done because of the alternative launcher that does not have the capability of putting the probe directly on track. However, KSP has taught me that more gradual burns (so over a number of passes too) are less efficient due to gravity drag and other phenomena.

Does anyone know how these two combine and why the craft is not boosted into its Mars orbit after the first pass?

In practice small burns are usually more efficient. The purpose of small burns is to burn closer to periapsis. For example three burns within 10 seconds of periapsis vs one burn within 30 seconds of periapsis. This is particularly true because high specific impulse engines typically produce a lower thrust.

If you burn perpendicular to the gravitational pull, gravity drag is zero, so that is not an issue. Other phenomena may include atmospheric drag, which is likely near negligible due to the brief time spent near the planet with each pass.

Whether a single burn to escape results in more mass I'm not sure. I believe ISRO used the multi-burn method because they have proven satellite engines that can perform the task. Like the saturn V this spacecraft was built using existing equipment in order to decrease cost and build time.

[Superluminaut]

cut

lol at tech support SN.

How are people responding to the launch there? Any public interest past nationalism?

[Camacha]

Thanks guys, I just realised this explanation myself when AFK. A faster, shorter burst would probably be more efficient, but the vehicle is not capable of such a thing. It also does not take into account the bigger engine needed, as the comparison is usually made between low and high intensity burns of the same engine and setup.

Like the saturn V this spacecraft was built using existing equipment in order to decrease cost and build time.

I understood that it also has to do with the failure or incompletion of the proposed big launcher. If what is needed will not work, you will need to make what's available work.