De-orbiting a Experiment Droppod

[Jestersage]

One of the best thing to come out with 1.2, aside form commNetwork, is the droppod for experiment. Finally have an Excuse to make some FSW satellite. (I think the US have something similar in the form of Discoverer 13)

That being said, what is the best way to drop the pod with experiment, especially on high altutude? So far I am using an ant, oscar, a OKTO and battery (to have reaction wheel), and the rest of the fixings so it can enter atmosphere and land. However, are there better ways to do so?

[Streetwind]

I've managed to do a fully "dead" reentry on a quick test I did. Was just the container, the small heatshield, a parachute, and four separatrons (moved to be fairly flush with the offset tool).

On decoupling, all of this was staged at once. The separatrons fired, pulling the container away from the ship and deorbiting it at the same time (spacecraft had to be facing retrograde, of course). Since the thing was aerodynamically stable, it flipped itself heatshield first as soon as atmospheric drag increased. And the parachute was pre-set to deploy below a certain altitude once safe.

I was surprised how much the separatrons actually managed to drop the periapsis - far more than I had intended. The lack of excess mass through uneccessary parts like probe cores and such probably helped a lot. Though if you want to drop it from a very high orbit... not sure how far it actually goes. I tested it only once, from low Kerbin orbit (somewhere between 70 and 80 km).

Ultimately, if you want to brake out of a higher orbit, you have only one choice: more reaction mass. So either you go the fully autonomous stage route, which you have been doing, and just add more fuel; or if you do a dead stage, like I did, add more and more separatrons until there are enough of them for the job. Gotta be mindful of the CoM after burnout though - the thing must be able to flip itself heatshield forward without control, after all.

[Jestersage]

According to wikipedia, the FSW-2 flew a 200km PE - 400km AP orbit. Not sure what is its Kerbin equivalent.

[Capt. Hunt]

1 hour ago, Jestersage said:

One of the best thing to come out with 1.2, aside form commNetwork, is the droppod for experiment. Finally have an Excuse to make some FSW satellite. (I think the US have something similar in the form of Discoverer 13)

That being said, what is the best way to drop the pod with experiment, especially on high altutude? So far I am using an ant, oscar, a OKTO and battery (to have reaction wheel), and the rest of the fixings so it can enter atmosphere and land. However, are there better ways to do so?

Yeah, although Discoverer was really a cover for a spy sat.  The whole linchpin of the Discoverer/Corona design was that it dropped the film canister to be recovered.

[Jestersage]

11 minutes ago, Capt. Hunt said:

Yeah, although Discoverer was really a cover for a spy sat.  The whole linchpin of the Discoverer/Corona design was that it dropped the film canister to be recovered.

So is FSW (they keep claiming about seeds exposure and microgravity etc)

[moogoob]

I used on on a probe from Minmus - just put the whole thing on a re-entry trajectory straight from Minmus transfer, then engaged chutes (open when safe, of course!) at the same time as the decoupling. Probe burned up, experiment module made it safely.

Though be aware - it did not count for "return vessel to Kerbin from Minmus Oribit" contract objective. Oh well - at least I got the science!

[fourfa]

2 hours ago, Jestersage said:

One of the best thing to come out with 1.2, aside form commNetwork, is the droppod for experiment. Finally have an Excuse to make some FSW satellite. (I think the US have something similar in the form of Discoverer 13)

That being said, what is the best way to drop the pod with experiment, especially on high altutude? So far I am using an ant, oscar, a OKTO and battery (to have reaction wheel), and the rest of the fixings so it can enter atmosphere and land. However, are there better ways to do so?

Don't need anything more than a science pod and a Mk16 parachute.  From a very low orbit near the atmosphere, a decoupler will literally slow it down enough to re-enter eventually, and it's so light that the chute won't overheat.  Not much choice in landing location though; it's going to take a lot of passes to finally capture.

A pair of Separatrons on the science pod will de-orbit with a fierceness.  Or, sometimes I'll deorbit stuff from a cargo bay by dropping the Pe of the mothership to deep in the atmosphere, release the payload, then quickly re-boost to circular orbit before I lose much altitude.