Discussion Your Venus/Mars mission concepts/proposals

[K_Jameson]

If it's based off Shakespeare, the diameter of the antenna is 3.01 m in diameter.

Efesto and Shakespeare shares the main bus, although with various modifications: the more obvious are the RTG instead solars, the modified scientific payload, the reallocation of the magnetometer boom and the dark thermal insulation on Shakespeare. Also, the atmospheric capsule is far smaller, lighter and simpler on Shakespeare than on Efesto and is housed on the side instead on the aft.

The two antennas are not actually the same: Efesto has a 2.9 meters HGA, with the front LGA on top of it; Shakespeare has a slightly larger 3.015 meters HGA, that support the LGA and a MGA (necessary as backup at the Uranus distance from Earth).

The interesting thing is that, because Uranus is much more farther than Venus and for the inverse square law, the communication rate allowed for Shakespeare is only about 1/340 of Efesto even though the similar antennas.

 

[Nicholander]

Oh, but I think my smaller antenna (1.33 meter diameter) will be fine, considering Mars' is a LOT closer to Earth than Uranus. Also, here's my rough SketchUp design if you haven't seen it:

It's 3 meters in diameter and 5.11 meters tall. That little "Circle" on the side is the antenna, and obviously those large panels are solar panels.

 

[K_Jameson]

1.33 meters is rather small... Because the gain is depending on the area of the reflector (at parity of other factors), such an antenna would have an efficiency of only 60% of the Mars Express antenna, that is 1.7 meters and, i think, the smaller HGA currently operating from Mars.

 

[ISProgram]

Determined the baselined launcher for VESPA-O will be the redesigned Verseau rocket; the payload capacity to Venus for the 2032 opportunity is 3152 kg, while VESPA-O isn't expected to exceed ~2700 kg wet.

In case it does, there is some margin for inefficiencies on the part of the launcher and Orbiter 2010.


Nicholander, with regards to your HGA diameter, it might be best just to widen it a bit.

For reference, MAVEN's HGA is 2.1 m in diameter, and has a downlink capability of 550kb/s. MRO's HGA, by comparison, is 3 m in diameter (the largest in orbit), and has a downlink capacity of 6Mbits/s! That's nothing to sneeze at, though PADSL probably doesn't need one that big anyhow.

PADSL will also need a LGA, for contingency communication option. Maybe dual redundant.

 

[Nicholander]

K_Jameson, what would be that 1.33 meter diameter antenna's bandwith, if it say had the same amount of power being put into it as MRO? I also realized I also forgot to put the side tanks on my model. :facepalm:

 

[ISProgram]

Like MRO, VESPA-O has a number of different configurations since it will need to operate in distinct mission phases.

VESPA-O will partially deploy its solar arrays (as the illustration shows) during the cruise to Venus and throughout the initial orbital phase.

The capsule will be jettisoned 10-20 days before VOI. After entering the initial orbit around Venus, the orbiter will act as a relay to the atmospheric probe. The probe will last about 1 month, after which the orbiter will unlock the HGA (which can be rotated on 3 axes, the preliminary model doesn't show the mechanism) from its stowed position.

The orbiter will than go through a 6 month(?) aerobraking phase, and once the circular orbit is achieved, the arrays will be fully deployed so that they can gimbal and allow for the orbiter to efficiently collect power (details later).

 

[Nicholander]

I've been thinking about remaking my Neptune flyby and atmospheric probe, and I have an idea that would completely redesign it, but allow it to have an antenna that's actually big enough to allow a decent bandwith. So, I may do that before working on PADSL.

 

[ISProgram]

Preliminary instruments on VESPA-O.

VESPA-O will carry AT LEAST 5 instruments, with a combined mass of ~100 kg.

VESPA Visual Monitoring Camera (V-VMC): While not formally a scientific instrument, and of poor quality, the images from this camera are primarily used to monitor the separation of the atmospheric probe which will be deployed by VESPA-O 10-20 days before Venus Orbital Insertion (VOI). After VOI, the camera may find some use in take global pictures of Venus from the initial elliptical orbit; after the aerobraking campaign, it will probably cease operations. Based off Mars Express’ VMC camera.

Venus Main Imaging Camera (VMIC): VMIC is a wide-angle, multi-channel CCD. It is designed for global imaging of Venus, and will provide much higher resolution than the V-VMC camera. VMIC will also be capable of operating in the visible, ultraviolet, and near infrared wavelengths. It will be used throughout the mission phases to search for volcanic activity, record airglow, and to specifically map the polar vortex. Based of Venus Express’ VMC camera, Rosetta’s OSIRIS, and Mars Express’ HRSC camera. Like HRSC, VMIC will include an FPGA to pre-process image data, and reduce the transmit load for these images.

Ultraviolet Imager (UVI): Among other things, this instrument will measure distribution of specific atmospheric gases in ultraviolet spectrum. Based off Akatsuki’s UVI.

Venus Radio Science (VeRaS): VESPA will utilize a radio sound experiment, transmitting radio signals which would bounce off Venus or pass through the planet’s atmosphere. Based off Venus Express’ VeRa experiment. VeRaS would, among other things, help determine the gravitational field of Venus, and estimate the density of any ion fields.

SPEctrometer for CharacTeRization of the Atmosphere (SPECTRA): Imaging spectrometer which will analyze radiation in the infrared and ultraviolet wavelength. Based off Mars Express’ SPICAM and Venus Express’ SPICAV.

Magnetometer: VESPA may have this instrument onboard, in which case it will measure the strength of Venus's magnetic field, as well as how it is affected by the interaction between the solar wind and Venus. Based off Philae’s ROMAP instrument and Venus Express’ MAG.

Venus Data Relay Capability: VESPA will carry a US Electra UHF terminal, and will be used to relay data from future landers or balloons on the Venusian surface. Due to mass constraints on the part of VESPA’s own atmospheric balloon, this system may not be used for it; however it will still be reserved for future Venus landers. Mars spacecraft use Electra too.

With regards to the instruments, K-Jameson (or anyone!), I would like input as to what other instrument(s) I should include, dedicated suite, etc. This only a basic list; note the 'AT LEAST' above. :thumbup:

---------- Post added at 05:13 PM ---------- Previous post was at 04:50 PM ----------

VESPA-O might follow a top-deck approach with regards to the instruments; placing them all on the top deck of the probe would help out with instrument pointing. However, the atmospheric probe would be attached to the top deck as well, so it would get into the instrument's line of sight (LOS) during initial checkout and cruise.

Additionally, even after the atmospheric probe separates, the adapter that attached it to VESPA-O might still pose a LOS issue, and the actual act of ejection from the orbiter might produce ejecta or damage the instruments that will be right next to it.

---------- Post added at 05:23 PM ---------- Previous post was at 05:13 PM ----------

Therein after, VESPA-O's atmospheric probe will be called Giovanni, after Giovanni Cassini (can't call it Cassini for obvious reasons), who thought that he had found a moon around Venus.

This name is not set in stone, I will not OFFICIALLY called it Giovanni (too bland). At the same time, I'm not calling it "VESPA-O atmospheric probe" for the remainder on this thread either.

Not calling it Neith either.

If you have name suggestions, I would love to hear them.

---------- Post added at 05:36 PM ---------- Previous post was at 05:23 PM ----------

Oh, and the only instrument set in stone at this point is V-VMC. It's needed for documentation of Giovanni's deployment from the main bus.

 

[Nicholander]

I have a name, tough It's a bit generic, Athena. (The Greek god of intelligence)

 

[ISProgram]

I have a name, tough It's a bit generic, Athena. (The Greek god of intelligence)

That does fit with the naming scheme for Venusian surface features, so it is an option. Only problem(s) is what you said earlier, and the fact that there is a Athena rover.

I think I should also mention that looking at PADSL has inspired me to do a similar mission for IPSA. Thanks...! :lol:

So let's see, current missions being worked on...VESPA-O, TSL, CASR, VESPA-S...

Oh, and I think it might be more efficient for PADSL to have fixed solar arrays (directly on the body), rather than deployable ones. The latter could get hung up on a rock.

I had also just remembered that PADSL is just like a mission to a comet called [ame="http://en.wikipedia.org/wiki/Comet_Hopper"]CHopper[/ame], at least with regards to the spacecraft technical goals. This blog also has some good information.

 

[K_Jameson]

Pretty good list of instruments. VESPA seems more specialized on visual imaging, while Efesto has some focus on field and particles science with less specialized instruments on the visual spectrometry, although with a powerful VIMS spectrometer (Cassini heritage) and another very specialized instrument that is the Fourier Transform Solar Occultation Spectrometer.
Anyway, the two spacecrafts can be considered roughly complementary.

 

[ISProgram]

Pretty good list of instruments. VESPA seems more specialized on visual imaging, while Efesto has some focus on field and particles science with less specialized instruments on the visual spectrometry, although with a powerful VIMS spectrometer (Cassini heritage) and another very specialized instrument that is the Fourier Transform Solar Occultation Spectrometer.
Anyway, the two spacecrafts can be considered roughly complementary.

Still formulating more instruments, with a rule not to exceed 11. If you have any to suggest, that would be nice.

More detailed posts to come. :thumbup:

---------- Post added 03-06-15 at 01:38 AM ---------- Previous post was 03-05-15 at 11:03 PM ----------

With regards to VESPA-A (the standalone capsule), wasn't there a similar design for a standalone atmospheric probe for Venus, that you did, K_Jameson?

I distinctly remember seeing that when I was a lurker here, before Imageshack betrayed us all. :lol:

 

[Dantassii]

The probe will last about 1 month...

Is that the surface probe on Venus will last 1 month? I'd love to see how you're going to do that. The longest a probe has lasted on the surface of Venus to date is on the order of 2 hours.

90 Atmosphere's pressure + 900 degrees C + Sulfuric Acid atmosphere = a mad race to see if the probe is crushed, melted, or dissolved first.

Dantassii
HUMONGOUS IMS shipbuilder

 

[K_Jameson]

You 're right.
For comparison, the Efesto probe was never intended as a long duration probe: is intended mainly as a mere descent probe, with actually only one instrument deployed after landing (the anemometer). Naturally, in Orbiter and with Sc3, the duration of the probe is indefinite, but we can assume that the communications will last only a bunch of minutes. Long-lasting probes must be designed in a radically different fashion, and still we don't expect durations comparable to a Mars lander. One of the problems is the power source: batteries have a short life; solars are unfeasible on the surface; RTG has serious problems in dispersion of the waste heat in such an environment...

---------- Post added at 10:13 AM ---------- Previous post was at 08:29 AM ----------

Still formulating more instruments, with a rule not to exceed 11. If you have any to suggest, that would be nice.

A good rule; Efesto has a similar number; Shakespeare maybe a couple more, thanks to other mass savings (RTG instead solars; far smaller atm probe with related structures, etc.). Galileo II, that is ludicrously big, has at least twice that number of instruments, but is really a unique case, because in its conception, the Jovian system was considered as a whole solar system that needs complete and detailed exploration, and the spacecraft was scaled as consequence, although the result is not as big as the NASA Jupiter Icy Moons Orbiter, nicknamed "Battlestar Galactica"...

For your instruments, I have no particular suggestions; observation in UV is really effective at Venus but your payload already cover that aspect. Maybe you can split the UV/IR spectrometer in two separate and more specialized instruments. I can also suggest a ion and neutral mass spectrometer, for direct sampling of the upper atmosphere during the aerobrake phase. Efesto has no INMS spectrometer because aerobraking is not in the flight plan.

What is the final science orbit? Efesto should be placed in a 24 hour elliptic orbit analogous to the Pioneer Venus 1.

With regards to VESPA-A (the standalone capsule), wasn't there a similar design for a standalone atmospheric probe for Venus, that you did, K_Jameson?

I distinctly remember seeing that when I was a lurker here, before Imageshack betrayed us all. :lol:

Yeah, was the first iteration of the Efesto probe. Only descent probe with expendable cruise stage, Mars style. I will recover the drawings...

 

[ISProgram]

Is that the surface probe on Venus will last 1 month? I'd love to see how you're going to do that. The longest a probe has lasted on the surface of Venus to date is on the order of 2 hours.

90 Atmosphere's pressure + 900 degrees C + Sulfuric Acid atmosphere = a mad race to see if the probe is crushed, melted, or dissolved first.

Dantassii
HUMONGOUS IMS shipbuilder

(puts on sunglasses) Kukukuku, I never said 'surface probe'! Mwahahaha!

Okay, but seriously, I think the longest a surface probe would last on Venus is ~12 hours, and that's being optimistic. VFM went for a 5 hour lifettime for their conceptual lander, which had a lot of technological development and maturation to it (like the rotating pressure vessel).

VESPA-O will carry an atmospheric balloon to Venus, which will float in the upper atmosphere where conditions are a bit more benign. VFM expected 30 days out of their balloon at 55.5 km altitude; my balloon is aiming for the same duration. The follow-on VESPA-A will carry a larger aeroshell to the planet, which will hold a balloon, and possibly, a lander (though I'm aiming for a stationary science package which isn't expected to survive surface impact, save for some instrumented penetrators).

Haven't really thought of a compact lander design yet. :facepalm:

What is the final science orbit? Efesto should be placed in a 24 hour elliptic orbit analogous to the Pioneer Venus 1.

VESPA-O is aiming for a circular orbit of 250 km (VFM's is 230 km) with a period of just a few hours (~2 hours), after the 6 month aerobraking phase. VESPA would continue operations in this orbit for >2 years, with possible mission extensions up to a additional <3 years. After this, the spacecraft would probably be deorbited.

The alternate orbit is a Magellan-type orbit (295x7762 km, ~3 hours), but VESPA probably won't be attempting extensive mapping cycles like Magellan did, at least not in the current baseline. VESPA-O's orbit is planned to be near-polar as well.

---------- Post added at 04:21 PM ---------- Previous post was at 02:32 PM ----------

While VESPA-O is still under a technical review with regards to its instruments, VESPA-A is near technical completion; I can pull out technical data for it if you were to ask.

The only issues with VESPA-A:

1) Should it include a lander (in addition to the balloon it's carrying) instead of a "surface impact platform"?

2) Not sure if it has enough delta-V. VESPA-A is approximately 3032 kg at launch, and only 31 kg of this is the hydrazine propellant. I need to refine the mass more. It's targeting launch in June 2034.

3) Should it carry "miniprobes"? Like MPL's Deep Space 2 probes, or more appropriately, the Small Probes from Pioneer Venus Multiprobe (but this drives up the dry mass and exaggerates the delta-V problem).

4) Should the cruise stage carry (any) instruments? Multiprobe's cruise stage carried a Ion Mass Spectrometer and a Nuetron Mass Spectrometer to record data as it disintegrated in the atmosphere. Also drives up the dry mass...

---------- Post added at 04:39 PM ---------- Previous post was at 04:21 PM ----------

The good news at the moment is that barring any unforeseen changes, VESPA is still light enough to launch on the same rocket configuration that VESPA-O will launch with, minus two SRBs! This is of course irrelevant since it will need more injection impulse to get to Venus, but still...

I should also have a full list of instruments for VESPA-O in the coming days.

Also, still interested in PADSL, I've admittedly started looking at concepts for what you're trying to accomplish, Nicholander. Not sure if you mentioned this already, but do you have a firm launch date?

---------- Post added at 04:42 PM ---------- Previous post was at 04:39 PM ----------

I've just finished a calculation for VESPA-A's delta-V...

It's just 23 m/s, nowhere near the 429 m/s need for Venus arrival. Of course, that could be for entering orbit around Venus, in which case, I need to find historical data on TCMs done by actual Venus spacecraft.

Standby...

 

[K_Jameson]

Why so little fuel?
VESPA-A seems a very big spacecraft with a dry mass of 3 tonnes... larger than Cassini!

---------- Post added at 06:42 PM ---------- Previous post was at 06:38 PM ----------

Not sure if this can be useful, but these are the descent phases of the Efesto probe:

 

[ISProgram]

Well, I'm don't adequately trust my own calculating skills, so I prefer to base my actual data off...actual spacecraft data.

VFM's aeroshell, as well as mine, are 2.65m in diameter; interestingly enough, the Mars Exploration Rovers (MER), as well as many Mars aeroshells, are of this same diameter. That didn't seem like a coincidence; perhaps manufacturing of VFM's aeroshell would have taken precedence from those made from Mars.

Anyhow, with the coincidence in mind, I chose to use MER's cruise stage as the basis for VESPA-A's cruise stage. MER's weighs 1063 kg and has 32 kg of hydrazine propellant. I used the same specs for VESPA-A's, and just stuck one of VFM's aeroshells on it. The result is what I mentioned in my previous post.

The main issue that I overlooked is the fact that the aeroshell I stuck on weighs 1969 kg, which is more than what MER weighs presumably. Wikipedia says MER weighs 1063 kg ALTOGETHER, which makes sense in context (Delta II is capable of a maximum payload to LEO of 6100 kg, and 1000 kg to escape), but seems to contradict the official website.

I'll need to look over more specifications, but VESPA-A should be lighter than what it currently looks to be.

 

[Nicholander]

Well, I did have a launch date that I calculated with trajectory calculator, but I forgot it. :facepalm:

 

[ISProgram]

Signing off for today, as I won't have a computer to access.

Nicholander, if you still want to talk about PADSL, I'm all ears. It'll have to wait till tomorrow though.

Here's a picture showing just how the two VESPAs compared to each other. VESPA-A is...WIP, you can see the central propellant tank in VESPA-O.

 

[K_Jameson]

Surely, MER is far lighter than VESPA-A, but if VESPA-A is not intended to perform orbital insertion, I don't think that adding some kilograms of propellant would be a serious problem, unless you are very, very close at the maximum capacity of your launcher. You need only the fuel for the trajectory correction in the Earth-Venus trip, that ain't so much.

Interestingly, I see only one tank on VESPA-O... monopropellant engine?