[meteorite-list] Critical Review for ESA's Mars Rover (ExoMars)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 21 May 2007 11:13:52 -0700 (PDT)
Message-ID: <200705211813.LAA29459_at_zagami.jpl.nasa.gov>

http://news.bbc.co.uk/2/hi/science/nature/6675287.stm

Critical review for Mars rover
By Jonathan Amos
BBC News
May 21, 2007

Europe's plans to send a robotic rover to the Red Planet in 2013 face a
critical review this week.

A top-level panel will meet in Paris to choose a single design concept
for the mission and determine whether the ambitious proposals are
affordable.

The European Space Agency delegates are being asked to approve an
upgraded - and much more expensive - vision than the one originally
outlined.

This would see ExoMars travel with an orbiter to relay data back to Earth.

Enhancing the mission in this way would free the rover from having to
rely on American spacecraft for communications with home.

It would require the whole package be launched on a bigger, more
powerful rocket; but this also means the robotic vehicle could traverse
the Martian surface with additional, or heavier, instruments to search
for signs of life.

"What we've been looking for is a concept that will maximise the
scientific return," Bruno Gardini, a member of the ExoMars project team,
told BBC News.

The team's recommendations will be subject to a review on Tuesday before
being handed to the Programme Board for Human Spaceflight, Microgravity
and Exploration.

The latter should settle on a final design concept and assess the need
to increase ExoMars' 650m-euro budget. Many tens of millions of euros
may be needed. A decision is expected on Thursday.

Tight challenge

For months, scientific and industrial groups across Europe have been
developing a number of concepts in parallel.

The early "baseline option" called for a rover to be launched on a
Soyuz-Fregat booster and landed on Mars using the bouncing gas bags
employed so successful by the current US vehicles, Opportunity and Spirit.

-----------------------------------------------

HEAVY EXOMARS CONCEPT

o Would still leave Earth in 2013; primary aim to search for life
o Use of Ariane or Proton rocket increases mission's total mass
o Permits bespoke orbiter for data relay and remote science
o Vented landing bags releases some design constraints
o Geophysics/environment study possible with static station
o But... concept requires Esa states to release more funds

-----------------------------------------------

In this baseline configuration, the European rover would have the
capacity to carry 8kg - perhaps a little more - of instrumentation,
including a drill or "mole" for burrowing beneath the Martian soil.

A Geophysics/Environment Package (GEP) would also be landed with the
rover. This fixed station, once placed on the planet's surface, could
sense "Marsquakes" and monitor the weather.

But the closer this concept has been investigated, the more limiting its
capabilities seem. The bouncing bags put tight constraints on the volume
of space into which the rover must be stowed.

This in turn restricts the maximum mass that can be given over to
instruments and makes it virtually impossible to carry a meaningful GEP
payload.

Disquiet has been expressed, too, at the configuration's intention to
use American orbiting spacecraft at Mars to relay commands and data. If
the US were to experience a spacecraft failure - as happened late last
year - communication could still be possible but the ExoMars mission
would be severely compromised.

It is for such reasons that design teams have been considering a
beefed-up concept. This would launch the rover on a heavy-lift rocket -
an Ariane 5 or Proton.

Heavy rationale

A bigger boost at launch would provide extra mass capacity for ExoMars
to travel with its own orbiter, which itself could do remote sensing of
the planet.

This concept also envisages using novel "vented airbags" to cushion the
rover's landing. The military technology inflates like pillows under the
vehicle and can support heavier payloads.

"For the rover's scientific instruments, the option of a bigger launcher
gives us something in the range of 16kg, which is twice as much at the
American rovers," explained Mr Gardini.

"In this case, we would also be able to carry a geophysical package -
and we are still doing the final calculations - probably in the range
20-30kg."

EADS-Astrium has been developing the rover's chassis at its UK base in
Stevenage. It has built a testbed to examine the vehicle's locomotive
capability, and to try out the autonomous navigation software that will
eventually guide ExoMars over the Red Planet's rock-strewn landscape.

Like all the design groups, Astrium has had to grapple with the
different mission scenarios and what they would mean for their segment
of the project.

The company's ExoMars group leader, Mark Roe, is convinced a heavy-lift
option is the most appropriate way forward.

"First of all, it would be good news because we would then get maximum
science benefit. And that's good news for Britain because we have people
here who are well positioned to be principal investigators in a
significant number of instruments," he explained.

"It's still going to be very challenging for the launch mass. You feed
that back and you find the mass of the vehicle, which is now about 190kg
to accommodate 16.5kg of payload. The smaller launcher will not give us
the mission that we really want."

Bigger picture

Some commentators are worried that Tuesday's meeting could turn into a
"go, no-go" decision.

If it is felt that the heavy-lift option is simply too expensive and the
current baseline design is viewed as delivering insufficient science,
then ExoMars could be shelved according to this viewpoint.

But few would be prepared to contemplate such an outcome. The rover
mission is the first step in an ambitious programme of Solar System
exploration, known as Aurora, which could eventually see European
astronauts walking on Mars.

To abandon ExoMars now would make a mockery of the programme and raise
serious questions about Europe's space capability.

It would also knock back a generation of scientists who have pinned
their hopes on the Aurora roadmap to deliver a Red Planet sample return
mission - a mission to bring back pieces of Mars rock for study in Earth
laboratories, where the full panoply of modern analytical technologies
can be deployed.

"The idea of sample return missions is generally becoming the thing
people really want to do in the planetary science community," observed
Dr Ralph Cordey at Astrium.

"Japan has had a go with its little Hayabusa probe and in Europe we are
very much hoping there will be a mission to an asteroid to do a sample
return.

"There is a limit to what you can do in situ, however many instruments
you take to these bodies. Bringing material back to Earth would
represent a huge step change in what you could achieve."

This week's meetings have to deliver clarity. Time is running short. The
launch of ExoMars has already been put back from 2009 to 2013, and
industrial contracts need to be issued soon to keep the present schedule
on track. If a single technical baseline is adopted this week, design
teams can then refine the concept.

"It would enable us to start to optimise it, which hopefully will bring
some mass benefit which, hopefully, we can then feed back and, maybe,
even get a slightly bigger payload. That would be terrific," said Mark Roe.
Received on Mon 21 May 2007 02:13:52 PM PDT