jinnantonix

How about information only mods like Trajectories? Kerbal Engineer? BetterTimeWarp?

Is Mechjeb allowed?

I have done low cost to Eve before. ISRU is mandatory, and re-usability is difficult. Adding in the mission time makes the strategy somewhat different again.

The tiniest probe for Duna.

Thanks @Exoscientist . I really enjoyed this challenge, it was a great learning experience. Like many, I was rather underwhelmed initially when I discovered there was no lander involved. The model allowed me to quickly verify that enormous challenge involved in a Europa orbiter, let alone a lander. Understanding that the radiation environment in the vicinity of Europa is so extreme, that it makes any extended stay at Europa very difficult. The Jovian orbit and fly-by mission design will yield the maximum science return (we will learn a LOT about Europa with the data). Can't wait for the results.

Europa Clipper mission to Jupiters Icy moons. I added in the Europa Orbiter because I believe it is technically a feasible science mission, and the mass is 273kg, so capable of being launched as NASAs declared the reserve mass for the mission.

Europa Lander modelled in KSP/RSS. With Europa eclipsing Jupiter.

Don't worry, there is ore there. Finding flat ground is the bigger challenge. That's why you need a probe.

I looked it up and hydrostatic pressure at the seafloor would be 130-260 MPa, corresponding to 13-26 km depth of a theoretical Earth's ocean. So possible to build a sub for that with current technology. I think the bigger problems are power and communications. Nothing is impossible.

With regard to the Star 48 kickstage. Lou Scheffer blogs https://forum.nasaspaceflight.com/index.php?topic=47579.msg2276806#msg2276806: Note: That the FHe 6400kg payload capability can launch the Europa Clipper (6065kg) hence the additional capacity for the piggyback payload (273 kg). So here's the payload sitting inside the Falcon's fairing:

Sending a submarine to Europa is an inspiring notion, but is presently science fiction, mainly because of the difficulty of drilling through 30km of ice crust. Humans have not been able to do that on Earth (yet). The concept of Cryobot may offer an answer, a lot of development needed. How much energy would be required to melt ice at an ambient temperature of -160 degC? Then the sub would need to survive 10,000 atmospheres of pressure. And finally how would the sub communicate and return data to Earth? Landing on Europa, while an inspiring thought, is logistically complex. Finding a safe landing site requires very detailed data. There is no atmosphere for braking velocity, or to provide passive stability. A skycrane would be needed so that the engine exhaust does not contaminate the surface and ruin the ability to collect pristine samples. Advanced AI would be required to pilot the craft completely autonomously. etc, etc. Technically it can be done, but it will not be cheap, nor without high risk of catastrophic failure. One false move, and $3.5 billion is entirely wasted. The detailed measurement of the plumes around Europa will reveal the chemistry of the subsurface ocean. The Europa Clipper will be making such measurements during each fly-by. The potential for life could deduced from such data. Perhaps a sampling mass spectrometer may even be able to identify dead alien microbes in the plumes? This would not require a lander, but a craft in orbit around Europa could make more accurate measurements. A lander mission (assuming no submarine) would really only accurately measure the chemistry of the surface, there isn't much else to be learned. But this could be more cheaply determined by an impacter with plume measurement by an orbiter. I have modelled such an experiment as a piggyback mission on the Europa Clipper, occupying the 273kg mass offered by NASA for additional science missions.

This is the trajectory planned. I am still not sure how the Star 48 is used Apparently not for a DSM. It is either at the start during TMI , or it is used to decelerate at Jupiter. The latter seems unlikley because I am not sure if the engine would be reliable after 4 years in deep space.

A question for those good at calculating orbital mechanics. NASA advise that the following is the schedule for the Europa Clipper transit to Jupiter: launch in October 2024 - 21-day launch window. Mars in February 2025 Earth in December 2026, arriving at Europa in April 2030. So 128 days from LEO to Mars? And then 1 year and 9 months back to Earth?

Hi all, A question for those good at calculating orbital mechanics. NASA advise that the following is the schedule for the transit to Jupiter: launch in October 2024 - 21-day launch window. Mars in February 2025 Earth in December 2026, arriving at Europa in April 2030. So 128 days from LEO to Mars? And then 1 year and 9 months back to Earth?

While researching I stumbled on this - the launch will include a Star 48 "kicker" Star 48B SPEC: AKA: 87.2-KS-17,735;TE-M-799. Status: In Production. Thrust: 66.00 kN (14,837 lbf). Gross mass: 2,137 kg (4,711 lb). Unfuelled mass: 126 kg (277 lb). Specific impulse: 286 s. Burn time: 87 s. Height: 2.03 m (6.67 ft). Diameter: 1.25 m (4.08 ft). This makes the launch payload as follows: Europa Clipper: 6065kg Piggyback payload: 273kg Star 48B: 2,137 kg Total = 8,475 kg The FHe cannot get this to Jupiter, but it definitely can get it to Mars. So that is clearly why this mission requires the Mars - Earth gravity assist to reach Jupiter. Star 48 Modelled with a Terrier engine and a "tweakscaled" R-4 Dumpling fuel tank

Europa Clipper with piggyback Orbiter (and now Star 48 "kicker") fitting perfectly into the Falcon payload fairing.

Is a lander mission more important than the Jovian-system orbiting mission? Firstly, it would not be possible to land on Europa without a very detailed survey of the surface topography. This could not be gathered efficiently from Europa orbit, because any mission that persists close to Jupiter will be subjected to harsh radiation that will limit the time available for collection and transmission of data. The Clipper mission's fly-by design has the advantage that it minimises radiation exposure to the craft, and also uses the time in higher altitude orbit to transmit the collected data back to Earth. Europa Clipper will be gathering all the required initial surface topography data from many fly-by passes and detailed analysis. It should be noted that any lander mission will be constrained by the payload of science instrumentation, and also the fact that it will only be able to survive the harsh radiation environment for a few weeks at most, as shielding will be too heavy to land with the surface probe. It is arguable that carrying a RTG or solar power system to the surface is therefore not justified, and the mission would likely be constrained by battery power capacity. Instruments should definitely be both a standard mass and Raman laser mass spectrometer, and a seismometer, noting that seismic data would be of questionable value with such limited time on the surface, and also has the problem that it generates large amounts of data for upload. Considering this, and the fact that a Jovian orbiter can carry much more science payload, and can generate a lot more science, plus has the time and opportunity to transmit that data back to Earth, I would argue that the Europa Clipper orbiter is certainly the best design for the initial mission. NASA has acknowledged that the lander mission is important and so is investigating an entirely separate mission with the target to put a lander on the surface of Europa, possibly with a separate craft in low Europa orbit with relay capability. The mission cost would be in the vicinity of $3.5 billion. That is a lot of money for a probe that will probably only remain active for 3-4 weeks on the surface, and gather only some surface chemistry (which could otherwise be obtained from plume data) and limited seismic data. We all are inspired by the idea of a lander, but is it worth it? Considering this, the costly and risky notion of beefing up the Europa Clipper mission with a Centaur or DCSS third stage is moot. It is clear, NASA wants to avoid risk to focus on the success of the more valuable Clipper mission, and is quite willing to wait for the Mars-Earth gravity assist in order to reduce risk and ensure success. Further speculation is not a valuable exercise. Having said that, it seems a waste leaving the possibility of adding a 273kg payload to collect more science . Having looked at the many proposals for using the piggyback option, I favour a Europa orbiter with an impact test to determine surface chemistry and also to collect more accurate data on Europa's tenuous atmosphere (plumes). The Delta IV Heavy has been retired, at $400 M per launch it cannot compete with SpaceX Falcon Heavy nor the impending Blue Origin New Glenn. The ULA Vulcan with a Centaur V upper stage will no doubt be a future contender for NASA contracts, but is still not projected to beat a FHe for maximum payload.

A few rules issues, I have sent PM. I am struggling to award an aesthetic point for the above fairing, doesn't look very realistic.

I have had a lot of fun building and testing Europa Landers, and can now categorically say the it is impossible to land a science experiment within the NASA's piggyback constraint of the 273kg mass limit. The craft needs 3500 m/s to transit from elliptical Jovian orbit to Europa orbit, and another 1500 m/s to land. For 20kg of science instruments, the best vehicle mass I could do was 750kg . I was however successful in building a model that could get into Europa polar orbit. Science instrument: Multi Spectral Imaging, including mass spectrometer 20kg Batteries: Lipo, 5kg Medium gain antenna 2kg Craft body and thrusters 15kg R-4D engine 20kg Propellant 150kg . dV =3532 m/s, unshielded Radiation shielding for transit 60kg The craft remains shielded until it reaches Europa, decoupling before orbital burn. The craft then orbits in low Europa orbit every 2 hours transmitting science data to the Clipper probe for as long as the battery lasts.

Looks pretty good to me. Remember you can clip empty fairings as much as you like to achieve aesthetics points, and then delete them from your craft in the VAB when scoring. So for example, you could clip structural fuselages and FLA5 adapters in between the crew cabins to improve the look. Also if your crew wants to pass between the crew cabins and the skycrane without ladders, you would need to add a docking port pair.

@Death Engineering looks like you are doing Artemis and Gateway construction from the start. I like it.

It's mainly due to timing of Hohmann transfers. IRL there is a typically a preference for one big Oberth burn using a hydrogen fuelled second or third stage. The Moon has an orbital period of about one month, whereas the launch window for an interplanetary mission is a few days at most. The Moon is rarely in the correct position to provide a significant gravity assist for the outbound craft. It can be done however, where the the final launch stage burns to TLI, and the upper stage then uses hypergolic fuel and multiple Moon gravity assists to raise Ap before a final Oberth burn at the Moon to reach solar orbit.

With the lander, the launch mass = 7085 kg. According to my simulation of the FHe with Clipper probe, the second stage reaches LEO with enough remaining fuel to provide a delta-V of 6.225 km/s, which is nearly enough to transit direct from Earth to Jupiter. I would assume that surely the extra 75 m/s could be provided by the Europa Clipper engines during a mid transit adjust. If that were so, why do so few deep space launches use the Moon for gravity assist? I don't think the Mun provides a good replication of real world gravity assists.

Europa Lander Mass (wet) = 1019kg. Includes 30kg science experiments, 15kg batteries. Propulsion is based on IABS with 2 x R4-D engines, but uses ACS: 12 x MR-111 thrusters Edit: this is far too heavy to be accepted and remain within NASA's conservative limit of 273kg for the piggyback. Back to the drawing board and spreadsheet. Looking to the prelim design studies Sylph "SmallSat", Mini-Maggie (CubeSat) and ELSA Neopod.