Tuesday, October 30, 2007

In a meeting held on 17 and 18 October 2007 in Paris, ESA’s Space Science Advisory Committee (SSAC) selected the new candidates for possible future scientific missions, under the Agency’s Cosmic Vision programme.

One of those missions, if approved, would be, undoubtfuly, a memorable adventure, an unseen quest for knowledge taking place in different scenarios.

That mission is TANDEM and since it is a possible future mission that really fills my glass I’ve decided to do a spacEurope Special about the theme.

Since the complexity of the mission doesn’t allow to descirbe it in a single post, I have decided to do it in four episodes.

Today I’m posting a mission overview, the following episode will focus on the Science Objectives, a third one will give a closer look at the possible payload to be incorporated in the mission and, finally, a fourth one counting with the precious participation of Athena Coustenis, the Project Leader and, as a bonus track, a predicted mission timetable.

So, put your helmets on because we are headed to Titan and Enceladus!



TANDEM OVERVIEW

The TANDEM project is being proposed as a multi-component exploration system to be built with partners from different nations (NASA at the top but also with the interest of Canadian investigators who proposed contributions for the mission’s payload) for a launch that can take place around 2020.

The proposed L-class mission concept has counted with the experience and enthusiasm of mroe than 150 scientists and engineers from all over the world, being many of them involved in the exploration of the Saturn system through Cassini-Huygens or participated in the past in mission designs for existing and future missions.

Where is TANDEM aiming? To the investigation of two different worlds in situ...Titan and Enceladus!

And how will this be achieved? The mission concept is quite ambitious and counts with an orbiter, a Titan aerial platform, Titan mini-probes, and, for the close study of Enceladus, penetrators/landers carrying a large variety of instruments is the solution being equationed.

The baseline mission concept is for two moderate-size spacecraft expected to leave the Earth around 2020 on one or two launch vehicles.
TANDEM will provide not only the referred in-sit uobservations (near or at the surface), but also remote science measurements of both Titan and Enceladus, this will be possible by the initial establishment of a new Saturn orbit (analytically validated) for the mission, that will visit periodically these two moons, and then subsequently enters orbit around Titan, to be joined shortly thereafter by separate Titan probes.

The two spacecraft, using chemical propulsion and radioisotope power (other options such as solar panels are also a possibility) will be a Titan-Enceladus Orbiter carrying also the Enceladus in situ package, and a Carrier for the Titan in situ investigation elements including the Titan Montgolfière and up to three mini-probes.



A Titan orbiter will be essential, in order to achieve the team’s key science objectives.
If most observations require a 3-axis stabilized spacecraft there are several measurements that would benefit from a spinning orbiter spacecraft element, this possibility will also be assessed by the TANDEM team.
Regarding communications, this orbiter would provide telecom relay between the different elements of the mission and Earth.
Already thinking about an eventual extended mission, the Titan orbiter would be possibly used as a platform to remotely study the Saturn system.


The Titan-Enceladus Orbiter will first go into orbit around Saturn and then, by using cycler orbits, it will make multiple flybys of Enceladus and fly through the plumes in its South Polar.
It will, then, deliver an in situ package including probably the mentioned penetrators to prime target sites on the moon’s surface.

After these operations the orbiter is expected to enter Titan's orbit and perform a series of observations, from its upper atmosphere to the magnetosphere interaction, from its surface to its interior for not only scientific reasons but also to perform the reconaissance, providing lower atmosphere climate and surface topography data that will allow
the Titan’s aerial probe to navigate safely down near its surface.

Then, after the initial orbiter phase is completed, its orbit will be circularized to prepare the support for the Titan probes arriving on the 2nd carrier vehicle.


What happens next? The balloon and probes will separate from the carrier and these will enter in Titan’s domains by using aerocapture.

The use of RTGs for the heat and electric source of energy, will permit to the balloon to stay active for months if not years in the misty moon’s atmosphere, sampling Titan’s lower atmosphere and surface close up using both remote sensing and in situ techniques.
At the end of mission the aerial probe, which will be able to deliver surface probes to Titan ground, could itself land at a prime target location.



Coming soon: TANDEM Science Objectives

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