RT 2 - Circularise orbit without maneuver nodes

[astrospud]

Hello all, I've kinda come up against a wall when it comes to precisely setting up a Remotetech 2 network. 

It's early on in Career Mode, and one of the juicy contracts is to set up a network with 4 sats, and another to Alt Map scan Kerbin (with network). I've upgraded the VAB, tracking Station and Launch pad once and I would've thought I would have access to node placement, but alas and alack, no. I've had quite a few hours put into KSP over the years, and you'd think I could successfully circularise and orbit from launch without using nodes. Nope. 

I have no idea what I'm doing wrong. With node, I can time the burn to 1/2 the Dv burn duration either side of the burn and generally get it bang on the money. Without node placement, I'd wait for Ap. and start my burn there. I look over at my engineer and it says my Apoapsis is holding (give or take), until my Periapsis starts climbing out of negative territory. Then my Ap. starts climbing rapidly. A life spoiled by access to nodes I guess. 

I've done searches for this, but all search results come up with no reference to Remotetech 2 and the need to remain in contact with ground station. The RT2 contact in question requires each satellite to have an eccentricity of no more than 0.04. How do I achieve this without nodes?

BTW, here's a small list of mods I'm running (don't laugh. There are some real crackers in that list I can't Kerbal without)...

 

Quote

KSP: 1.1.2 (64bit) - Unity: 5.2.4f1 - OS: Windows 10  (10.0.0) 64bit
Toolbar - 1.7.12
USI Tools - 0.7.2.1
Ambient Light Adjustment - 2.5.6.3
Chatterer - 0.9.8.1230
Community Resource Pack - 0.5.1.1
Contract Configurator - 1.11.5
Contract Pack: Anomaly Surveyor - 1.4.3
CC-CP-SCANSat - 0.6.0.1
Contract Pack: Field Research - 1.1.7
Contract Pack: Bases and Stations - 3.2.1.2
Contract Pack: The K Files - 1.1.1.3
Contract Pack: RemoteTech - 2.0.2
Crowd Sourced Science - 3.0.2
DMagic Orbital Science - 1.2.4
Contract Parser - 1.0.3
Contracts Window Plus - 1.0.6.3
Progress Parser - 1.0.4
Engine Lighting - 1.4.3
EVA Struts - 1.0.1
EVA Transfer - 1.0.4
Firespitter - 7.2.3
HeatControl - 0.3
Interstellar Fuel Switch - 2.0.1
RasterPropMonitor - 0.26
KAS - 0.5.7
Kerbal Engineer Redux - 1.1.1
Kerbal Joint Reinforcement - 3.1.7
KIS - 1.2.9
KSP-AVC Plugin - 1.1.6.1
KWRocketryRedux - 3.0.4
Infernal Robots - 2.0
Modular Rocket Systems - 1.12.6
ORIGAMI Antennas - 0.9.5
NearFuturePropulsion - 0.7
NearFutureSolar - 0.6
PlanetShine - 0.2.5
Procedural Parts - 1.2.1
RCS Build Aid - 0.8
RealPlume - Stock - 0.10.7
RemoteTech - 1.7
SCANsat - 1.1.6.1
Stock Visual Enhancements - 0.6.4
TextureReplacer - 2.4.13
TweakScale - 2.2.10
USI Core - 0.2.2.1
Asteroid Recycling Tech - 0.8.2.1
USI Exploration Pack - 0.5.2.1
Freight Transport Tech - 0.5.2.1
Kolonization Core - 0.2.2.1
USI-LS - 0.4.2.1
USI Survivability Pack - 0.5.2.1
UKS - 0.40.2.1

 

[bewing]

If you start burning prograde a little before your Ap, the Ap will slowly scoot forward ahead of you in orbit. If you control the thrust of your burn properly, the Ap will stay about the same distance ahead and not gain any altitude -- all the time, your Pe will be rising. You often need to thrust limit your engine, and just touch the thrust a little for this to work. It's just another trick that takes practice.

[Snark]

You can also tweak things a bit by aiming slightly above (radially outward of) or below (radially inward of) prograde.

For example:  Suppose you start your burn a little before you get to Ap.  You're pretty close to Ap, so you're going mostly horizontally, with just a teeny "up" component (assuming that you're holding prograde).  Your goal is to raise your Pe to be close to your Ap, without raising your Ap too much.

Well, if you burn strictly prograde in that condition, you will rase your Pe by a lot... but you'll also be raising your Ap in the process.  You'd like for your Ap not to rise too much.  Well, you can tip your rocket slightly downard (just a few degrees)-- this will tend to "depress" your Ap while still allowing your Pe to climb.

Similarly:  Once you get past your Ap, so that your altitude is now decreasing:  you do the same thing, except tip your rocket up slightly.  That will accomplish the same thing (depress your Ap while letting your Pe continue to rise).

In other words,

• Tipping slightly below prograde will lower your Ap if it's in front of you, but raise your Ap if it's behind you.
• Tipping slightly above prograde will raise your Ap if it's in front of you, but lower your Ap if it's behind you.

 

The other thing you can do is spread out the burn.  This works fine even without any of the tipping described above-- you can do it while holding steady prograde the whole time.

1. Start your burn slightly before Ap.  "How much before" may take some trial-and-error.  You want to be pretty close to Ap... but if you're too close, you won't have enough TWR to keep your Ap in front of you.  Just try it and see.
2. As you burn, your Ap will move forward.
3. Ideally you want your Ap to move forward just slightly faster than your ship is catching up to it.
4. If you're burning full-throttle and your ship catches up with and overtakes your Ap ... you waited too late to start the burn.  Go back to step 1 and start your burn a little earlier. 
5. The longer you burn, the more the Ap will start to accelerate ahead of you.
6. When you see it start to "run away" ... stop burning and wait to catch up with it.  Then go back to step #1 again.

Just repeat that cycle.  When your Pe starts to get close to your Ap, you'll find that it'll hit that "run away" condition much sooner (because when your orbit is getting close to circular, just a small amount of dV will move Ap by a lot).

You'll probably have to iterate only two or three times before you're close enough to count as circular.

[HebaruSan]

What I do is (based on a previous forum post by someone else that I've lost track of):

1. Use SAS to lock prograde
2. Go to map screen once your Ap is around 70 km (maybe earlier once you've practiced this a few times)
3. Hover mouse over Ap marker to see your time to apoapsis
4. Adjust throttle to keep this between 30 and 50 seconds; so if it's below that, throttle up, and if it's above, throttle down
5. Continue till Pe marker rises above 70 km
6. Allow your time to apoapsis to drop below 30 during the final stretch, with the goal of reaching 0 seconds exactly as Pe reaches 70 km

As bewing says, the "Ap climbing rapidly" is your time to apoapsis getting away from you. If you watch that number directly and keep it in a suitable range, you'll prevent that from happening. It's not so tough once you get a sense of how different throttle values affect it.

[astrospud]

All great answers here, thanks! 

Last night I tried several times to keep my Ap ahead of me, but was always at below 30s to Apoapsis, now I think about it. With nodes, I've almost always needed a burn time near 1 minute for the Dv to circularise, thus halving that burn time to 30s or so either side of Ap. I will practice the with all the advice stated above. 

Many thanks!

[James Kerman]

You need to upgrade mission control as well as the tracking station to access nodes.

[astrospud]

Yeah, I just found that out last night as well!