EDL = "Entry, Descent and Landing". EDL requirements for Mars borders on perverse. Mars has a surface gravity of 38% the Earth's but a surface atmospheric pressure of about 6 millibars (the Earth is one bar). The Martian gravitational field is strong enough that slowing down is tricky (the Moon is much easier). The Martian atmosphere is thick enough that a heat shield for hypersonic entry is required. However the atmosphere is so thin that a normal sized parachute will not slow a vehicle down to less than 50 meter/sec. This requires some sort of tricky technology to kill off that last 50 meter/sec, e.g. air-bags, surface penetrator, retro-rockets, etc. JPL tried a cheap-and-nasty surface penetrator with DS-2 but it failed. There's lots of basalt rocks laying about on the Martian surface. A surface penetrator is going to shatter if it hits a piece of basalt. The Soviets and British tried cheap-and-nasty parachute / air-bag / retro-rocket combos but they all failed. Many people (myself included) suspect Beagle-2 was too cheap-and-nasty. However you only have to tweek Beagle-2's design up a little bit and you'll have an EDL system almost as sophisticated as MER. Compared to Earth, Venus, Titan and the Moon, landing on Mars is very difficult to do. MER might(?) have the most low-tech / low-cost EDL system possible that has a decent probability for success.
Gary
Space/Science » in reply to re: I would like to see weather stations and seismometers all over the surface of Mars...either of which need to move around much.
What's their EDL system?
The whole thread (46 posts)
- Beage 2: As I was saying
- a portrait ..
- Predictions, anyone? How long before ESA offers competitive prizes like NASA now is?
- A Difference Overlooked
- David Whitehouse lurks the Habitable Zone.
- You know this for a fact?
- Another article about Beagle 2
- Exactly on point
- re: Exactly on point
- Standard practice is to design for the worst case scenario
- Importance of feedback from protypes
- re: Standard practice is to design for the worst case scenario
- Standard practice is to design for the worst case scenario
- re: Exactly on point
- Exactly on point
- don't hold your breath for a refund (n/t)
- Sounds like what they said about Mars Polar Lander. (n/t)
- Let the space organization that does not have at least one pile of multimillion dollar junk littering the Martian surface, cast the first stone. (n/t)
- re: Let the space organization that does not have at least one pile of multimillion dollar junk littering the Martian surface, cast the first stone.
- A big difference
- Yes, there are some differencess...
- re: A big difference
- re: Beagle 2 was 'too great a risk'
- You're missing the point
- re: You're missing the point
- How much extra would Beagle 2 have cost if they used the NASA airbag sytem?
- Many space scientists said MPL's landing system was doomed to failure BEFORE it arrived at Mars. (n/t)
- re: You're missing the point
- You might be right.
- A big difference
- re: Let the space organization that does not have at least one pile of multimillion dollar junk littering the Martian surface, cast the first stone.
- Let the space organization that does not have at least one pile of multimillion dollar junk littering the Martian surface, cast the first stone. (n/t)