New Mars Forums

dicktice

Member

From: Nova Scotia, Canada

Registered: 2002-11-01

Posts: 1,764

Re: Hopper mobility schemes

The unique conditions on Mars could be better utilized per mission perhaps by adopting various hopper schemes to get around. Initially, for example, if a lander arrives by parachute to slow it down in the atmosphere, with a controlled rocket-burn for a precision touchdown--wouldn't it be feasible to reuse the same lander to take-off on a ballistic trajectory and then parachute to a controlled touch down again somewhere else? Thus, having repacked the parachutes and refueled the rocket from available subsurface water resources, more than one site could be visited on the same mission. Variations of this scheme should immediately come to mind, depending on whether the mission is exploratory, supply, rescue, sample and return, limited only by one's imagination.

dreammaker

Member

From: poughkeepsie, ny

Registered: 2007-01-01

Posts: 26

Re: Hopper mobility schemes

thats not a bad idea. instead of a rover.. we'd use the lander to explore places within the landing site.. instead of just using it to get back to the ship in orbit.. i like it for it saves weight and adds more work for the lander.. which should actually drop the cost of a mission.. or allows us to bring more material..

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Hopper mobility schemes

Yes and no,

First of all, you need quite a bit of Hydrogen for this scheme (on the order of 10-20MT probably for two hops) which will require an awful lot of water and power plus likely a larger ISRU plant. But most importantly, getting that water reliably is the tough part. You might need a pretty big drill and some means to extract tonne-quantities of water. Bigger fuel tanks too probably.

I am also very dubious of repacking parachutes under any circumstance, since if they fail, then you are dead.

Lastly, the HAB lander and the return vehicle, be that the MAV or ERV, are two separate things. If you make a "hop" in the HAB far away from one or the other, and get stuck, you are dead. If you "hop" in the ERV or MAV, you won't have enough fuel to return to space without time/equipment/water to make more fuel. I don't like the idea of flying the ERV/MAV around a lot either, since they are so important.

Oh and almost forgot, repacking and reflying a nuclear reactor isn't happening: the reactor only starts making radiation after it is started up the first time, but it will continue making radiation for some months after it is turned off again. None of the concieveable Mars missions budget enough shielding mass for the reactor to be so close (attached to) any manned vehicle. Instead of shielding, they simply put the reactor far away with long power cables.

---

[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

dreammaker

Member

From: poughkeepsie, ny

Registered: 2007-01-01

Posts: 26

Re: Hopper mobility schemes

well what if instead of the main hab.. you have a smaller lander packed with supplies that when unpacked, you could used it as a hopper. you'd have to have the all the fuel onboard and i agree with you as to taking a nuclear reactor with you.

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Hopper mobility schemes

Well, that adds a lander to either mission probably, which will drive up costs.

Once a central site is chosen for a base, maybe NASA can send a reusable hopper/lander or two, which would pay for themselves and then some if it could bring crews or small payloads to/from orbit.

---

[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,431

Re: Hopper mobility schemes

If it were possible to seperate the ascent stage from the descent stage you could reuse the descent stage if you could refuel it and wire it up with some additional electronics to make a stand and go system much like a large scale jet pack.

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Hopper mobility schemes

That would be an awful lot of trouble, and if you messed up and dropped the MAV, then what?

Also, MD and DRM-III call for the ascent first stage to double as the descent stage I bet.

---

[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

Austin Stanley

Member

From: Texarkana, TX

Registered: 2002-03-18

Posts: 519

Website

Re: Hopper mobility schemes

Hoppers are a great method for adding planetary scale mobility to a Mars Mission, but they are fairly massive and not as reliable as a rover.  Idealy you want to have two hoppers ready for deployment at any one time in case one brakes down.  Their fuel consumption is also considerable.  They are a great idea for a established based, but not a Rover replacment IMO.

lso, MD and DRM-III call for the ascent first stage to double as the descent stage I bet.

They should, it adds another back-up in case you aren't able to redveous with the orbital module for some reason, you can still escape back to the martian surface.

---

He who refuses to do arithmetic is doomed to talk nonsense.