Skycrane, Innovative landing technology Options

[erwan]

Thanks for the link, Lyford; now back on topic!

[erwan]

Back to skycrane: a kind of 'LEM like', but with full automated descent, and not any real time human control; just to consider the level of informatic upgrade since 1970s; i wonder if Apollo computing power was not lower than an up to date personal scientific calculator....

[cIclops]

Obviously they have success with a slow landing from a hundred feet on a flat pad (I couldn't find any info on the guidance control or nav they are using... GPS?), but I think the kicker is going to be the real time hazard recognition - finding a flat landing zone and going to it autonomously before the fuel runs out...

... and if you want to know what happens when the fuel does run out see this page from John Carmack's blog and the video (4MB) at the end.

Yes the vehicle uses GPS which is unlikely to be available on Mars, however careful site selection and radar ranging together with an Apollo style contact strip for the final meter should cut it.

[erwan]

Cyclops: "uses GPS which is unlikely to be available on Mars" I readed (where?.... Lyford Help please!) that: about the future human space US missions ( first Moon, next Mars), a system analog to GPS (or instead: beacons previously released on the lunar soil, instead of satellite constellation) is likely programmed for the lunar step of the program. Thus, although certainly not available for MSL 2009, i guess humans will not land on Mars before a kind of GPS system will be avalaible there!

[lyford]

... and if you want to know what happens when the fuel does run out see this page from John Carmack's blog and the video (4MB) at the end.

Yes the vehicle uses GPS which is unlikely to be available on Mars, however careful site selection and radar ranging together with an Apollo style contact strip for the final meter should cut it.

Ouch! Any paragraph beginning with the title "Complete Loss of Vehicle" is a sad read... chalk one up for unmanned flight: At least no one was hurt - though some debris seems to get too close to the camera, which is also hopefully "unmanned!"

Love the view from the rocket going up, nothing beats it.

As far as the last meter down, I am just worried about a Big Joe issue like on Viking 1. If it had just come down a few meters over from where it landed, it wouldn't have survived. Of course, MRO should identify all hazards down to under a meter, but that could still ruin the lander if it's unlucky enough to hit it with the contact strip first and cut engines before touching down. And even a palette style lander may end up so tilted as to hinder egress.

The Skycrane may actually help in this since the rover suspension should be able to handle uneven terrain... While admittedly a long shot, the worst would be something like this, MSL just teetering back and fort, spinning its wheels:



"Skycrane reports successful separation - engine cut off - all systems nominal - rover reports zero wheels on Mars."

[lyford]

Cyclops: "uses GPS which is unlikely to be available on Mars" I readed (where?.... Lyford Help please!) that: about the future human space US missions ( first Moon, next Mars), a system analog to GPS (or instead: beacons previously released on the lunar soil, instead of satellite constellation) is likely programmed for the lunar step of the program. Thus, although certainly not available for MSL 2009, i guess humans will not land on Mars before a kind of GPS system will be avalaible there!

There's this, but it's not expected to happen anytime soon, it was just a study. They can do rough positioning now with MGS and Odyssey, but it's not that accurate or fast. You can even track with just one satellite and doppler shift, if you know the satellite's orbit exactly, but it's not something that can happen in real time like with GPS. So a lander is pretty much going to be able to recognize where it is and where it wants to go on its own brain power...

[erwan]

Lyford: thanks for your swift links...

[Guest_BruceMoomaw_*]

Two comments. First, MTO is supposed to serve not only as a Martian comsat but as a navigation satellite, allowing (I believe, although I'll have to recheck this) location of other orbiters and landers with an accuracy of several hundred meters.

Second, keep in mind that the hazaard avoidance radar system on MSL's descent stage is supposed to identify and avoid large boulders as well as hazardously steep slopes, reducing the danger of Lyford's scenario.

[Guest_BruceMoomaw_*]

Also, in regard to Erwan's comment: I have heard that the average new automobile sold now contains more computing power than the Lunar Module did.

[lyford]

Two comments.  First, MTO is supposed to serve not only as a Martian comsat but as a navigation satellite, allowing (I believe, although I'll have to recheck this) location of other orbiters and landers with an accuracy of several hundred meters.

Hi Bruce - I have heard something like this as well but the reference escapes me. I think the MarsNetwork was to have something like MTO as its centerpiece, though the page hasn't been been updated since 1999!

Second, keep in mind that the hazaard avoidance radar system on MSL's descent stage is supposed to identify and avoid large boulders as well as hazardously steep slopes, reducing the danger of Lyford's scenario.

Well, my "MSL on a half shell" was a silly scenario to be sure, and they can obviously can test any descent hazard recognition system easily on Earth (and I think on Mars somewhat with Phoenix in 2007). It would really be astronomically (!) bad luck to land on such a rock, but then we did get a "hole in one" on this mission, which was incredible good luck. I think I will breathe easier when I see the great images from MRO -

[MahFL]

The LM's computer was very very slow compared to todays PC's, and when the Eagle landed it was overloaded and Armstrong had to land manually with only a few seconds of fuel remaining for the descent engine.

[ilbasso]

Here are a couple pictures of the Lunar Lander Training Vehicle (LLTV), originally called the Lunar Lander Research Vehicle. The astronauts referred to it as "the flying bedstead." Grumman built 4 of them. According to Gene Cernan, only 1 of them was left by the time he was practicing for the Apollo 17 landing. Cernan said the LLTV was actually harder to fly than the LM. It was equipped with a big jet engine which provided enough thrust to counteract 5/6th of the pull of Earth's gravity and that big engine - firing more or less straight down - made the trainer more unstable than the LM.

Attached are two pictures - a stock photo of the LLTV from 1967 and a photo of Neil Armstrong parachuting to the ground after ejecting from the LLTV in May 1968,





You can also read about the LLTV training at:
LLTV Training - NASA

[ilbasso]

Oooh! Oooh! I found these juicy film clips of the LLTV in action:

LLTV videos (NASA)

Two things strike me in watching these:
(1) Human beings are incredibly creative to come up with such things; and
(2) It takes BIG cojones to have the guts to fly one of these things!

[dvandorn]

Oooh!  Oooh!  I found these juicy film clips of the LLTV in action:

LLTV videos (NASA)

Two things strike me in watching these:
(1) Human beings are incredibly creative to come up with such things; and
(2) It takes BIG cojones to have the guts to fly one of these things!

Cojones? I dunno -- it's a matter of risk vs. reward. If you flew one of those things, you got a shot at landing a LM on the Moon. That's a pretty decent risk investment, in my book... *grin*...

-the other Doug

[erwan]

Cojones? Guess i must buy an extended english/US-french dictionary?!