Request DGIV: From Europa to Io

[Parduz]

Hi all. It was a long time since my last post (even the forum tells me that i've never posted before).

I'm trying to do the DGIV scenario "Rescue Mission on IO".
I'm unable to enter in a Io orbit. The best i have obtained so far is to travel near it after a sort of slingshot around Jupiter. I was too fast so i spent all the fuel without even obtain a visible curve around Io.

Can someone write a tutorial for that mission? Other than "Open this, set that, change here" i'd like to know WHY "set that" and "change here"

Thanks in advance.

 

[Kveldulf]

Possibly a stupid question, but you aren't using the stock settings for the DGIV are you? If you dont load custom settings, the DGIV only has enough for a trip to ISS, not cruise around the Jovian system.

 

[statickid]

Besides chaning the settings, another thing you can do if you're feeling elaborate is take the smaller amount of fuel and load a fuel box into your cargo bay. Then when you are cruising to Io or are orbiting it, you can release the cargo and dock with it to refuel.

On the flight side of things, you can save some fuel by escaping from europa retrogradedly and things like that

 

[n122vu]

Besides chaning the settings, another thing you can do if you're feeling elaborate is take the smaller amount of fuel and load a fuel box into your cargo bay. Then when you are cruising to Io or are orbiting it, you can release the cargo and dock with it to refuel.

Or, if you have UCGO and DGIV-2 in this Orbiter installation, you can load the UCGO fuel containers in the bay and use fuel directly from them. Just sayin...

I prefer the docking method statickid mentioned though. That's how I used to do "realistic" moon trips in the DGIV by using the minimum fuel and engine configurations.

May have to give this scenario a try myself this weekend. Need to brush up on my interplanetary/intra-system transfer skills.

Interested to know how yours turns out!

 

[Parduz]

I'm sorry, i don't understand your answers:
Kveldulf: the scenario starts with a DG landed in Europa, that needs to rescue another one landed on Io. So them are already on the Jovian system.
Statickid and n122vu: are you telling me that the mission is not doable as it is?

 

[dgatsoulis]

Possibly a stupid question, but you aren't using the stock settings for the DGIV are you? If you dont load custom settings, the DGIV only has enough for a trip to ISS, not cruise around the Jovian system.

The dV required for something to reach the ISS in Orbiter (assumption: you launch as close to the equator as the Space-shuttle does) is approximately
7500 m/s.
The "default" DGIV has a dV of ~ 24000 m/s.
An estimate for the dV required for the "Landed on Europa - landed on Io" mission (within the time-frame) is about half that. ~12000 m/s.

Statickid and n122vu: are you telling me that the mission is not doable as it is?

It's more than doable. Nonetheless it IS a [hard-short] mission. And one that's worthy of being picked for one of the 2010 challenges scenarios. In two versions!
1: use the least amount of fuel.
2: use the least amount of time.

 

[Parduz]

It's more than doable. Nonetheless it IS a [hard-short] mission. And one that's worthy of being picked for one of the 2010 challenges scenarios. In two versions!
1: use the least amount of fuel.
2: use the least amount of time.

So, i guess that a tutorial to do that is'nt coming shortly....

 

[statickid]

I've never personally had any trouble parking into Io orbit, I mainly bring the fuel in my cargo for the other delta glider, but if I mess up or botch the flight I take a little for my rescue DG as well.

P.S. don't bother landing on Io :hmm:

---------- Post added at 05:19 PM ---------- Previous post was at 05:17 PM ----------

I like to bring the old fuel cargoes because it gives me an excuse to do some docking and I also like to put the empty can back into the DG with an astronaut EVA, so it gives me an excuse to do eva as well and take in the sights with the weird breath sound effects and funky robotic rcs mode voice that cracks me up.

---------- Post added 10-16-10 at 12:00 AM ---------- Previous post was 10-15-10 at 05:19 PM ----------

ok I know this is of very limited help to you but i just did the scenario and with the medium trip fuel, (moon and ISS) I found it very easy to get into Io orbit with at least half fuel, and I actually messed around alot on the way there seeing if I could second guess TransX with course corrections... the answer is "no". My best advice for saving fuel is to launch off of Europa to the east and instead of burning entirely retrograde to Jupiter, fly more towards the direction of 270(in terms of Jupiter orbit). Not alllll the way, but kind of. then Europa will put you off course so when or before you are about at Pe of your Jupiter orbit, make course corrections that put you back on track to Io waaay before you get there. Once you get there, just do a burn pointed at your retrograde to Io orbit. It will seem like a very long burn but you should have tons of fuel when you're done parking in orbit.

Also my DG was pretty heavy because I brought the fuel can for the other DG

 

[Izack]

I don't like to use the old fuel cargo, because it supplies the DGIV with unlimited fuel and O2. It is fun to release>dock>transfer>undock>EVA though. :thumbup:

 

[statickid]

I skirt around this "problem" by having self control and only extracting a limited amount of fuel from it and no oxygen

 

[Parduz]

I still don't get how i can go to Io without an orbit (very elliptical) around Jupiter.... which give me too much speed to been grabbed by Io gravity.

 

[statickid]

more or less like this. This one's a little messed up but I did that so you could see where they are intersecting. a little course correction would fix it :thumbup:

 

[flytandem]

I still don't get how i can go to Io without an orbit (very elliptical) around Jupiter.... which give me too much speed to been grabbed by Io gravity.

Yes... You will be arriving with a lot of speed at Io. You won't be able to just coast to an orbit around Io. You will need to do a burn near your Pe at Io to slow to orbital speed. (Orbit insertion burn) This may be something like 5000 m/s dv.

I just flew this challenge but found it specifically a challenge to find the ship on the surface. For landings on these moon I have always used reentry MFD and targeted a "base". The GLMinning ship is not at a base so it was invisible to reentry MFD. I used the white axis line in TransX to estimate I was on heading to the target ship and do some pen and paper to estimate the distance (as shown in Docking MFD) when I should start to burn the retros so as to stop near the ship. Maybe there's a way to target a ship on its own on the surface but I didn't see it. Any ideas?

 

[statickid]

There are two ways that I've found:

The first I feel maybe a little bit like cheating, but it works well. I have successfully found and landed by the ship using the docking mfd but this takes alot of fuel IMO.

the second way that I was eluding to when I said "p.s. don't bother landing on Io" is very simple indeed. The rules say

"Your mission is to start from Europa in another DeltaGlider IV, meet the the stranded ship, and refuel them so they can go back home. "

However it does not say that there is any specific way to meet them. I noticed the stranded ship has a bit of fuel and O2. Simply launch the stranded ship into orbit and rendezvous with them! This is my method anyways. Also it is easier to give them a fuel container in orbit than it is on the surface. I feel that this would probably be true on the real moon. Also since the vessel is lighter it would take less fuel to get into orbit with an empty tank than with a full one so it is more efficient!

 

[n122vu]

I don't like to use the old fuel cargo, because it supplies the DGIV with unlimited fuel and O2. It is fun to release>dock>transfer>undock>EVA though. :thumbup:

I used to do it the even-harder way.

1. Open cargo bay doors and EVA
2. Grab the TurboPack
3. Maneuver above the cargo bay
4. Release the fuel container from the bay
5. Grapple the fuel container
6. Using the turbopack, maneuver the fuel container to the DGIV nose and release, allowing the container to dock with the DGIV
7. Transfer fuel and O2
8. Undock
9. Grapple the container and return it to the cargo bay
10. Stow the turbo pack
11. End EVA, close nosecone
12. Coast to the moon with MCC as needed.

 

[flytandem]

There are two ways that I've found:

The first I feel maybe a little bit like cheating, but it works well. I have successfully found and landed by the ship using the docking mfd but this takes alot of fuel IMO.

the second way that I was eluding to when I said "p.s. don't bother landing on Io" is very simple indeed. The rules say

"Your mission is to start from Europa in another DeltaGlider IV, meet the the stranded ship, and refuel them so they can go back home. "

However it does not say that there is any specific way to meet them. I noticed the stranded ship has a bit of fuel and O2. Simply launch the stranded ship into orbit and rendezvous with them! This is my method anyways. Also it is easier to give them a fuel container in orbit than it is on the surface. I feel that this would probably be true on the real moon. Also since the vessel is lighter it would take less fuel to get into orbit with an empty tank than with a full one so it is more efficient!

Good catch to notice the Mining ship still had fuel. It was misleading when the scenario instructions stated the fuel had all leaked out. It had enough fuel to not even need to be rescued. :facepalm: I flew it off Io and went to Europa and docked with the wheel with 1599 m/s dv to spare. Also plenty of O2.

 

[statickid]

oh wow i didn't know it had enough fuel to do all that! I guess it was also misleading that it says that it needed to be rescued! I never tried to do anything more than get into a small orbit!

 

[n122vu]

Io-ronic. I had Googled the subject to see if there were any tutorials out there. The VERY FIRST result was a thread right here on O-F, which included a few posts by none other than flytandem - I JUST finished reading those posts in a thread from 2008 on the very matter, and hopped over here to see if anyone else had any suggestions for the OP.

http://www.orbiter-forum.com/showthread.php?t=6080

 

[djidji]

Io-ronic. I had Googled the subject to see if there were any tutorials out there. The VERY FIRST result was a thread right here on O-F, which included a few posts by none other than flytandem - I JUST finished reading those posts in a thread from 2008 on the very matter, and hopped over here to see if anyone else had any suggestions for the OP.

http://www.orbiter-forum.com/showthread.php?t=6080

lol I was wondering why I had a deja vu reading this thread.. it was mine that you found back then.. while I did manage to make this mission. .I a still unable to do the VIP to mars one.. if anyone can help..

 

[Tommy]

My solution for the Mars bound VIP went about as follows:

1: Used IMFD to plan a trip from starting place (Titan, I think?), slingshot off Saturn, to Mars. I note the time of the trip, and about where the Saturn Pe is. IMFD will try to do the whole burn at once-during the Titan ejection burn, but that's not efficient.
2: When Titan is opposite of the planned sling's Saturn Pe, I used Orbit Eject (set to "lower orbit") to leave Titan, with the goal of setting up a Hohman transfer to the Saturn Pe.
3: As I approached Saturn I recalculated the sling to Mars (now using "self" as a source) and used the AB when I neared the Saturn Pe.

I did perform a few manual adjustments during the trip from titan to Saturn - checking the dVp in slingshot - to minimize the plane change element of the sling burn. You are traveling quite fast by that point so you want the burn to be prograde, and you want to have made all your plane adjustments as soon as possible after leaving Titan.