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ESA to Deploy Mars Express Radar
fenimor writes "Mars Express was launched on 2 June 2003 and reached the planet on 25 December 2003. After eight months of intensive computer simulations and technical investigations the European Space Agency has given the green light for the MARSIS radar on board Mars Express spacecraft to be deployed during the first week of May. Assuming that this operation is successful, the radar will finally start the search for subsurface water reservoirs and studies of the Martian ionosphere."
Mars was in its closest orbit in 60,000 years when it launched, so it reached there in 7 months.
Hence the name "Mars Express".
I'm willing to bet the cost will be very similar...
And you'd lose. Keeping people alive in space is EXPENSIVE. They need air, food, a place to poop, things to keep them occupied for months so they don't go nuts, exercise equipment...
We can send a couple hundred (or less) kilogram probe to Mars on the most cost-efficient multiyear route. To send a couple hundred kilogram human, you'd need to send tons and tons of extra mass just to keep him alive, and you'd need to use a very cost-inefficient trajectory to get him there as quickly as possible, which means tons and tons of fuel.
Then you gotta get them back.
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At 186,000 MPS, it's the strength of the signal, not the distance traveled, that matters. In this context, the distances from orbit are insignificant, and the depth of rock only somewhat less so. It's the echo from the water under the rock that's being returned to the sattelite, not imaging data.
Googling for info on earth orbiting radar platforms lead me to more info on earth orbiting radar sattelites that you'd ever need
basic radar technologie:
larger waves penetrate deeper into solid things.
Satelites have detected beds of rivers in the sahara wich are now covered by a dessert
The larger the wave however also limits the size of objects to be found.
It depends a lot on the material you are trying to penetrate. Ice is easiest, so there should be useful data over the poles, then dry sands is next. Remember the space shuttle's sierra mission worked pretty well (but it was a much longer wavelength). They should be able to see through rock and gravel a little way, as long as it's dry or frozen. It's important to remember that water is very reflective for radar, so the water table should be noticeable, if they can get any signal down to it.
As others have pointed out, you can look up information on ground penetrating radar, but it's a little different in how it works, since the antenna is coupled directly to the ground you don't have to deal with surface reflection problems. From space there is the hard problem of deciding which echoes are subsurface and which echoes off nadir (to the side).
Oh, and they aren't hoping for pictures, just ranges. I'm not sure if you meant "pictures" literally, since SAR radars normally produce very cool pictures, you might expect them.
From TFA:
ESA's decision to deploy MARSIS follows eight months of intensive computer simulations and technical investigations on both sides of the Atlantic. These were to assess possible harmful boom configurations during deployment and to determine any effects on the spacecraft and its scientific instruments.
The three radar booms of MARSIS were initially to have been deployed in April 2004, towards the end of the Mars Express instrument commissioning phase. They consist of a pair of 20-metre hollow cylinders, each 2.5 centimetres in diameter, and a 7-metre boom. No satisfactory ground test of deployment in flight conditions was possible, so that verification of the booms' performance had to rely on computer simulation. Just prior to their scheduled release, improved computer simulations carried out by the manufacturer, Astro Aerospace (California), revealed the possibility of a whiplash effect before they locked in their final outstretched positions, so that they might hit the spacecraft.
The plan was to deploy the booms a year ago, but the manufacturer discovered that deploying the booms may damage the satellite, so the deployment was postponed. After nearly a year of looking at the problem, they have now decided that the possibility of damaging the satellite is small enough that they will proceed with the deployement.