Project Galileo II probe to Jupiter

[K_Jameson]

Yesterday, successful landing tests on Europa with LOLAmfd. The tank capacity must be increased 30% for allowing some hovering time during the final approach.

 

[K_Jameson]

A critical design flaw resolved: the delicate engine bells are now enclosed in protective covers against micrometeoroids.
Meanwhile, the radio and plasma wave package was completed with two more instruments, derived from the Cassini spacecraft: the magnetic search coils and a Langmuir probe. Finally, a second low gain antenna was added for a 360° coverage.

 

[K_Jameson]

In these days, analysis of the candidate landing sites on Europa.
Best candidates are the Castalia Macula, the Thera Macula and the Tara Regio.
Thera Macula is probably the best site for the scientific return; Castalia Macula has the advantage of the equatorial position (better accessibility), but the disadvantage of an harsh radiation environment. Tara Regio is a less young and active terrain in respect to the two above (potentially less attractive), but has the lowest radiation levels.

Meanwhile, a launch date was defined: 29/10/2013 (a VEEGA window), with live coverage on Orbiter Live Missions. Another window occurs at 04/09/2013 (a VVVGA window) and can be used in the event of a splitted launch (Galileo II and the lander).

 

[K_Jameson]

The Salviati carrier spacecraft at the first test into the simulation.
The lander is under the protective cover (the small golden dome).



The spacecraft has two large solar arrays, identical to the ones aboard Antares (except for the textures), for a total area of 38,72 square meters. Expected power supply: 313W at Jupiter, plus the modest amount generated from the mini-RTG of the lander (estimated: 60/65W)
No scientific instruments aboard the carrier, except for a cosmic dust analyzer, identical to the one aboard Galileo II, and a laser altimeter, for precise determination of the position in respect to Europa, during the pre-EOI phase.
Atop the carrier, we have the braking stage for the EOI maneuvre (a Star 48V solid rocket modified for deep space operations) and then the lander.
Total mass: 6691 kg of which 4868 of fuel.

---------- Post added at 11:57 PM ---------- Previous post was at 11:44 PM ----------

Detail of the lander atop the new Star 48V braking stage (protective cover jettisoned).
The braking stage is spin-stabilized and has no RCS system, so must be positioned in the correct orientation prior to the release from the carrier.

 

[MaverickSawyer]

Nice!
My one concern is propellant grain stability over long duration free-fall conditions. Will the propellants degrade over the course of the multi-year cruise to Jupiter? (I'm assuming that a small membrane is placed across the nozzle and that the thrust chamber is filled with helium or nitrogen to prevent outgassing issues.)

 

[K_Jameson]

A good observation; maybe the propellants can degrade; anyway, we have precedents: a STAR solid stage was used in the Magellan probe for the Venus orbit insertion, 1.5 years after the launch, and similar solid stages are contemplated in some NASA publications for Europa and Mercury landers, with an even longer flight time. I will post the links at the pdf that i have taken as reference.

---------- Post added at 10:13 AM ---------- Previous post was at 09:26 AM ----------

Maybe i can add some insulation like this:

---------- Post added 04-11-13 at 12:22 AM ---------- Previous post was 04-10-13 at 10:13 AM ----------

One of the possible future designs derived from Galileo II: a probe for the exploration of the Uranus system (tentatively named "Shakespeare"). Unlike Galileo II, this is a light and simple design, with a full weight of only 1800 kg, allowing a direct hohmann transfer to Uranus (via Jupiter gravity assist) with a Jarvis E launcher.

 

[Pipcard]

I get it, because many of Uranus's moons were named after Shakespeare's characters.

 

[boogabooga]

I recommend the name "Herschel"

 

[Pioneer]

Name the lander Galilei

 

[K_Jameson]

I recommend the name "Herschel"

There is already the ESA infrared observatory with the same name, although near the end of its operational life...
Anyway, this is only a concept. A serious study of this addon will not start before some time.

The current name of the lander is already definitive. :thumbup:

 

[K_Jameson]

I will post the links at the pdf that i have taken as reference.

As promised, here some of the documents taken as reference for the Europa-focused part of the mission:

Mercury Lander
Europa Lander

:tiphat:

 

[K_Jameson]

Integration test of the Galileo II with a Jarvis E launch vehicle.
Note that, in this test, is assumed a dual launch strategy, with the Europa lander and its carrier atop another Jarvis. This aspect has yet to be decided.



---------- Post added 04-19-13 at 09:49 AM ---------- Previous post was 04-18-13 at 06:13 PM ----------

The stack in LEO after a test launch.

 

[K_Jameson]

A new version of the mission logo:



(from left to right: Venus, Europa, Jupiter, not to scale of course)

 

[Pipcard]

I like the Star Trek allusion. Also, this.

 

[K_Jameson]

I did some math. I have discovered that, with the best of the best of our launchers - the Quasar 452 with an additional kick motor that can be a Jarvis C third stage - we could inject the 12-tons Galileo II in a direct hohmann transfer to Jupiter.
This would be great, but with some drawbacks:

1) we lose the Venus encounter
2) I should redo the logo :lol:
3) exorbitant launch costs (but perhaps minor overall mission costs, because of a far shorter flight time from Earth to Jupiter).

A depiction of this hypotetical configuration:


(I start to think that the name "Galileo" brings bad luck to the spacecrafts... this mission has undergone so many modifications, redesigns and delays to beat the original one... and after long time we aren't yet on the launch pad...)

 

[boogabooga]

Quasar 452 needs more things to launch.

 

[K_Jameson]

News and second thoughts.

First of all, forget the post above. My calculations were wrong, because i've assumed a delta-V for the hohmann transfer of 8.8 km/sec instead of the correct value of 6.3/6.5 km/sec. Then, the direct transfer can be achieved with a more reasonable Jarvis M launcher instead of the monstruous Quasar 452. A launch window for the hohmann trasfer opens on September 13, 2013.
Anyway, this strategy is currently matter of debate in the team, because a direct launch with the use of a superlauncher of this class is considered somewhat less realistic than a standard gravity-assisted launch with a more modest rocket.

Here, a test with the Galileo II mated with a HES-5 (the upper stage of the Jarvis M). The result is similar in appearance with the Galileo/Centaur G-Prime stack.

In case of a hohmann transfer, we lose the Venus encounter. Here, the logo without Venus!


Hohmann is more fuel conservative for the spacecraft (no important deep-space maneuvers, transfer time of only 2.7 years instead 6), and Jarvis M has some margin for additional weight, so we have the opportunity of a more complex flight plan around Jupiter. Ultimately, the Europa minilander can be rejoined with the main probe, eliminating the carrier.

The Venus probe is not lost: will be launched separately in a new autonomous and low-cost mission, christened "Efesto" that will be launched on a Neptune-1 rocket on October 13, 2013 on the FOI live channel, Orbiter Live Missions:

 

[K_Jameson]

A test on the launch pad with the Jarvis M.



Fausto is against the use of a superlauncher for the jovian probe... I am also undecided, but the J-M is cool! :rofl:

 

[K_Jameson]

Some brief news:

- the secondary HGA antenna (green circle) now has a two-axis liberty of movement, so the spacecraft can mantain the direct link with Earth also when is pointed away for observations (although at a data rate of about 1/30 of the main HGA), unlike Cassini. The secondary HGA has various purposes: 1) communication relay with the Europa minilander; 2) backup for the main HGA; 3) gravity science investigations.
- the langmuir probe was doubled and repositioned (red circles)
- the launch on Orbiter Live Missions has two windows: 13 september 2013 (in case of a direct hohmann with Jarvis M) or 29 october 2013 (in case of a VEEGA with Jarvis E).
13/9 is the most likely.



---------- Post added 06-02-13 at 11:44 AM ---------- Previous post was 06-01-13 at 08:50 PM ----------

Another modification involves the Salviati lander main engine. Taking inspiration from the Viking landers, the single 490N engine bell was replaced by eight smaller nozzles, to disperse the exhaust and minimize contamination on the ground during the landing.