Tuesday, June 14, 2011

Goals of ESA's Mars Demonstration Lander

In the previous post, I reported on the instruments planned for ESA's 2016 demonstration Mars lander.  Questions have been asked as to why this lander will be purely battery powered with a life on the surface of a day or two.  I wrote to Giacinto Gianfiglio, ExoMars System Engineering Manager, and asked him why solar panels allowing longer life had not been included.  He replied,

"In a larger Lander configuration indeed there were deployable solar array panels foreseen, but this solution would have implied:

-     soft landing with air bags (that we have now discarded for volume-mass-cost reasons)
-     deployable panels of the landed structures (that we have now discarded for volume-mass-cost reasons)

We have also changed the mission objectives from a relatively long life lander (one to two months) to a "demo" lander of only about two days of surface life time ... this enables to survive with just batteries .... and gain all this is to save volume-mass-cost."

This lander is part of a larger effort by ESA to develop technologies to explore Mars that also includes development of the capabilities needed to design and operate a rover on Mars.  ESA's website states:

"The task of MREP [Mars Robotic Exploration Preparation Programme] is to define and prepare for the next steps that Europe will take after these [the 2016 mission]... ESA has a distinguished history of space science missions, but the demands of Mars Sample Return (MSR) mission mean moving the Agency far out of its technological comfort zone. ESA does not currently have expertise in precision soft-landing probes and operating them on planetary surfaces, identifying and retrieving samples and then – as is a requirement for MSR – having them take off again to dock remotely in Mars orbit. Then there is the difficulty of preserving the samples in pristine condition and getting them safely through re-entry back to the surface of the Earth... MREP sets up a framework for more systematic and structured international cooperation with the United States and other exploration partners in the decades to come, enabling an increased number of missions than either partner could achieve alone. The target is to have Europe present on each mission slot to Mars - which is every two years - as mission leader or important contributor."

Editorial Thoughts: Why create program focused technology development? The U.S. Decadal Survey report had this to say about the importance of technology development in enabling planetary missions: "Continued success of the NASA planetary exploration program depends upon two major elements. It is axiomatic that the sequence of flight projects must be carefully selected so that the highest priority questions in solar system science are addressed. But it is equally important that there be an ongoing, robust, stable technology development program that is aimed at the missions of the future, especially those missions that have great potential for discovery and are not within existing technology capabilities. Early investment in key technologies reduces the cost risk of complex projects, allowing them to be initiated with reduced uncertainty regarding their eventual total costs." 

The Decadal Survey report included two examples of how focused technology development programs enabled subsequent planetary missions. The Solar electric propulsion (SEP) had been proposed for many solar system exploration missions, but none of those proposals had been implemented.  In 1998, NASA launched the Deep Space One mission to demonstrate the use of SEP and a number of other technologies.  While the spacecraft carried out limited science goals during encounters with the asteroid Braille and the comet comet Borrelly, the focus was on technology development and gaining experience operating a SEP spacecraft.  The demonstration of this technology led to NASA accepting the use of SEP in the Discovery Dawn mission to the large asteroids Vesta and Ceres.  (And allowing us to enjoy the in depth mission updates of JPL's Marc Rayman, who has participated in both missions.)  The second example was the development and operation (on Earth) of a series of rovers and the Mars Pathfinder landing system that enabled the Mars Spirit and Opportunity missions at Mars.

Today's ExoMars program is part of a joint ESA-NASA Mars exploration program that allows the two agencies to share costs.  As a result, the ExoMars program has had to be significantly modified and delayed to match NASA's technical and budget requirements.  Through the replans, ESA has continued its focus of using the ExoMars program to develop its technical capabilities so that it can be an equal player in the joint Mars program with NASA.  The decision to fly a demonstration lander with a focus on technology development with minimum science goals appears to come from that continued focus.

There has been a lively debate at the Unmanned Spaceflight forum as to whether this demonstration lander is a good investment for ESA.  I generally don't care to comment on political issues (and where to allocate investments is a political decision; my opinion is no more valid than those of my readers).  I will point out that right now the future of landed missions on Mars is subject to the whims of the U.S. political system as only NASA possesses developed Mars entry and landing technology.  Having a second space agency invest in these capabilities does not seem unreasonable.  What kinds of missions might make use of this technology?  If the joint NASA-ESA sample return program doesn't move forward (and likely won't past 2018 without a higher projected planetary budget for NASA), ESA could use this technology for post 2018 rovers, polar landers, or geophysical stations.  Once the technology is developed, it will be much easier to approve missions that use it, just as it was to approve the Dawn and Mars Exploration Rover missions once their underlying technologies were proven entities.

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