Yes! We ARE going to Europa!

[Exoscientist]

The head of the committee in Congress overseeing NASA is a strong supporter of not only a Europa orbiter mission but an actual landing mission. This means it's very likely to be approved:

A Europa lander is possible, JPL scientists say, and Congress appears likely to support it.

Posted on May 8, 2015 | By Eric Berger

http://blog.chron.com/sciguy/2015/05/a-europa-lander-is-possible-jpl-scientists-say-and-congress-appears-likely-to-support-it/

However, rather than the $2 billion cost being estimated by NASA, such a mission could be undertaken for costs in the hundred million dollar range if we only sent a small size lander of the Mars Pathfinder/Sojourner variety.

The reason why I say this is the delta-v requirements to land on Europa are surprising low once you arrive in the Jupiter system and use a Ganymede gravity assist:

Europa Cryo-Ocean Exploration Submersible (ECOES) Project.

Preliminary Design Report

http://www.lpl.arizona.edu/~jmoores/ECOES.pdf

However, when I discussed this on another orbital simulation forum, some members did some calculations disagreeing with these numbers. What do the Kerbalites think? Are they reasonable?

Bob Clark

Edited May 21, 2015 by Exoscientist

[xenomorph555]

Nothing confirmed just yet so be patient, for now it's a click-bait title.

[Motokid600]

Gives SLS a payload. Good stuff.

[billbobjebkirk]

Gives SLS a payload. Good stuff.

We really need a payload for SLS between 2018 and 2024, so I desperately hope that a Europa mission of some kind gets picked up for the real EM-2.

[smjjames]

I think they should be given 2 billion in funds for that anyway.

[xenomorph555]

Wait What!, $2 billion!

WHY WILL IT COST 2 BILLION DOLLARS!

And for that matter why does it have to launch on SLS.

[tater]

Wait What!, $2 billion!

WHY WILL IT COST 2 BILLION DOLLARS!

And for that matter why does it have to launch on SLS.

We have paid for SLS, so now they need to use it. If you buy delicious pork, you can't let it sit out and rot.

[Robotengineer]

Wait What!, $2 billion!

WHY WILL IT COST 2 BILLION DOLLARS!

And for that matter why does it have to launch on SLS.

To go to distant places you need a huge rocket... On the cost, IIRC, Curiosity/MSL cost 2bil, so for something that will go much farther and require more redundancy, thats cheap.

[Wesreidau]

Pff. Two billion dollars is only 1/6th the cost of a Gerald R. Ford - class supercarrier. Uncle Sam's just cleaning out the couch cushions.

[TARDISES]

Hmmm... Sounds like a good time to either reread 2010 or think about what kinds of SCIENCE could be achieved.

(I'd add "fly to Eeloo" to the list but my KSP experience is pretty much bound to Kerbin's SOI)

[Robotengineer]

What are the DV requirements for Enceladus?

[AngelLestat]

The only that I ask, that this mission needs to be enoght to gather all the data needed to plan an under ice mission.

[xenomorph555]

To go to distant places you need a huge rocket... On the cost, IIRC, Curiosity/MSL cost 2bil, so for something that will go much farther and require more redundancy, thats cheap.

Oh I didn't realise MSL costed 2 billion, that fine then. Still though how heavy is this thing that it requires the SLS, Cassini was launched with a Titan IV.

[Wesreidau]

I love how the representative basically said "go big or stay home". Texan for sure.

[smjjames]

Wait What!, $2 billion!

WHY WILL IT COST 2 BILLION DOLLARS!

And for that matter why does it have to launch on SLS.

So that they can direct the unused fundings to other stuff. NASA really needs to be funded better you know.

[Kryten]

Oh I didn't realise MSL costed 2 billion, that fine then. Still though how heavy is this thing that it requires the SLS, Cassini was launched with a Titan IV.

The options were a multi-flyby mission with a heavy EELV (Atlas V 551 or Delta IVH) or direct transfer with SLS. The multi-flyby trajectory would require the spacecraft to operate within Venus orbit and last about twice as long in transit in general, neither of which would be cheap.

EDIT: Also that's for the base mission without a lander; building spacecraft and instruments that can survive these conditions is not cheap. Estimates for a lander from JPL itself are $700 million-$1 billion extra, and you can probably double that for real costs. If Shelby gets his wish and a lander does get funded, this will have no real prospect of actually flying.

Edited May 21, 2015 by Kryten

[Jonboy]

While I share OP's enthusiasm for a Europa mission ... yikes. That title. Just stick "maybe" in there and it wouldn't be so misleading.

[Findthepin1]

It doesn't have to cost anywhere near $2 billion. If we send a probe straight into solar orbit from Earth, it might require less fuel than to orbit Earth then transfer to solar orbit. Launch, do the out-of-atmosphere burn, get to space, then just keep the engines on until you are on track for a Jupiter trajectory. Fine-tune that path so it goes right over Europa, and wait. Once you're at your Europa periapse, burn to a stop and fall straight down. Then land as usual. Done. The lander need not be very large, only enough to carry the fuel and a payload. IMHO this is cheaper.

[Guest]

Wait What!, $2 billion!

WHY WILL IT COST 2 BILLION DOLLARS!

And for that matter why does it have to launch on SLS.

A plain, straight-up SLS launch would be at least $500m

[Karriz]

It doesn't have to cost anywhere near $2 billion. If we send a probe straight into solar orbit from Earth, it might require less fuel than to orbit Earth then transfer to solar orbit. Launch, do the out-of-atmosphere burn, get to space, then just keep the engines on until you are on track for a Jupiter trajectory. Fine-tune that path so it goes right over Europa, and wait. Once you're at your Europa periapse, burn to a stop and fall straight down. Then land as usual. Done. The lander need not be very large, only enough to carry the fuel and a payload. IMHO this is cheaper.

That's still going to cost 2 billion, as it requires SLS and has a lander. I'm not sure where the cost savings would come from.

I hope the lander gets properly funded, but if it doesn't, then flyby mission is better than no mission at all, I guess.

[Bill Phil]

That's still going to cost 2 billion, as it requires SLS and has a lander. I'm not sure where the cost savings would come from.

I hope the lander gets properly funded, but if it doesn't, then flyby mission is better than no mission at all, I guess.

We could probably muster an orbiter at least...

I would certainly like to have a landing, though...

[Kryten]

We could probably muster an orbiter at least...

I would certainly like to have a landing, though...

Multi-flyby mission is superior to orbiter in terms of data return due to radiation and bandwidth issues-an orbiter would be fried pretty quickly by the radiation belt around europa, while a multi-flyby mission can dip into it and then transmit the data from a safe position. As for a lander-bear in mind we currently have little idea of real surface conditions. Designing for that is hard.

[cryogen]

What are the DV requirements for Enceladus?

It varies a lot. It depends how much patience you have to wait for gravity assists. Here's an actual study I found: a NASA concept for an Enceladus orbiter. They calculated a very low delta-v trajectory, with the tradeoff that it'd take 12 years from launch to Enceladus orbit.

http://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_059320.pdf

(the chapter "Concepts of Operation and Mission Design")

In their solution, the launch vehicle would lift to C₃ = 11.7 km²/s​², and the orbiter would use 2880.6 m/s of its own propulsion. That's roughly the same as 6.6 km/s from LEO to low Enceladus orbit. (If you're in LEO, it takes 3.72 km/s to reach C₃ = 11.7 km²/s​²).

The low-C₃ launch is for a gravity-assist tour to Saturn (Venus-Earth-Venus-Earth-Saturn). This would take 8.5 years, plus one 350 m/s deep-space maneuver to set up a flyby.

Saturn orbit insertion costs 960 m/s (eccentric orbit, low periapsis & high apoapsis).

Transfer to Enceladus orbit is just 1041 m/s, but it uses 52 gravity assists from Saturn moons, taking 3.5 years.

Remaining 484.3 m/s is "statistical".

Edited May 21, 2015 by cryogen

[Guest]

GGA === Good Game All?

Hrm... roughly 6.5km/s for the LV to make up, plus 4km/s available on arrival, this spacecraft is going to be pretty damn small.

Thus, if we instead choose an indirect gravity-assisted route like Galileo, it is not unreasonable for us to assume that we can get 2715kg in system resulting in a maximum dry payload of 820kg once we have arrived at Europa.

Eh, they can probably get the job done with that.

[cryogen]

GGA === Good Game All?

Probably "Ganymede Gravity Assist".