[CoderDozer]

Originally Posted by slade_x

You can't test a rocket, no more than you can test a firework.

You can test a model/design but every rocket that fires is expended and unreusable, so the first time the actual rockets used on the skycrane fired was on mars.

The hydrazine type rockets used called "MLE" (Mars Lander Engine) were derived from the viking missions apparently

Thanks for that, but what I guess im really asking was how did they design/test/know that the powered descent stage would work? Like I said I've seen the drop test but not a test on the powered descent, I imagine it would be impossible to test on earth with the different environments, so would it have been based entirely on simulations (and a bit of luck)?

[Mountainsandh]

[slade_x]

Originally Posted by Sintel

Thanks for that, but what I guess im really asking was how did they design/test/know that the powered descent stage would work? Like I said I've seen the drop test but not a test on the powered descent, I imagine it would be impossible to test on earth with the different environments, so would it have been based entirely on simulations (and a bit of luck)?

Good question, although i cant really answer that with any certainty but what i woud imagine they have tested is a mock up rig of the powered descent skycrane on earth with enough fuel, thrust etc. for earth parameters like gravity, atmospheric density etc. for testing stability for example (making sure the rockets were placed adequately for a stable landing). The calculations involved woudnt really need much practical testing as rocket science is now a proven and reliable discipline. Simulations may well suffice.

Unfortunately the only way to test the deployment of parameters with mars in mind would be just simulations based on calculations that have proven to work on earth. which is basically where rocket science knowledge obviously originates.

They would have done the same thing for the apollo lunar lander descent and ascent stages. To make sure the descent stage/ lander didnt crash into the lunar ground (exactly like making sure curiosity didnt crash into martian ground) and that the ascent stage could get back up into orbit around the moon to redock with the command module for the return trip home.

[jumpjack]

Originally Posted by Mountainsandh

is this picture of first laser shot?

[Rubecula]

If you are interested the next month's Sky At Night is about Curiosity on Mars.

[shedweller]

Originally Posted by jumpjack

is this picture of first laser shot?

I believe it is. No results back yet.

In other news, it looks like wheels will be turning on tuesday or wednesday this week.
http://www.space.com/17174-mars-rove...rive-soon.html

The Curiosity rover is set to make its first tracks on the Red Planet Tuesday or Wednesday (Aug. 21 or 22), mission team members said. The maiden drive will be something of a test, so the 1-ton robot won't be allowed to stretch its legs right off the bat.
"Basically, we want to drive the wheels more than one rev in both directions," said Jeff Biesiadecki of NASA's Jet Propulsion Laboratory in Pasadena, Calif., one of Curiosity's 16 drivers. "What we've got sketched out right now is about a 4-meter drive forward, and about a 90-degree turn in place, and a couple meters backwards."
Everything looks good so far, researchers have said. It's now time to test out Curiosity's driving system, a stepwise process that begins today (Aug. 20) — Curiosity's 15th full day on the Martian surface, or Sol 15 in mission lingo. [Photos: Curiosity's 2nd Week on Mars]
"On Sol 15, we're going to check out the steering actuators," Biesiadecki told SPACE.com. "We're going to run all the steering actuators one at a time — not through their entire range of motion but through both directions — and end them straight. So we should have all our wheels straight at the end of Sol 15."
If all goes well, the first drive should occur on Sol 16 (which begins Tuesday afternoon), Biesiadecki added. Curiosity will then pause to commemorate her first tentative steps on Mars.
"At the end of that maneuver, we'll be taking images of our tracks," Biesiadecki said. "We'll see the very beginning of our tracks, which I think is going to be kind of a cool picture."
The photography isn't just for historical or gee-whiz purposes, though. The team wants to see how much Curiosity sinks into the ground when it's on the move, Biesiadecki said.

We'll also see how gently the descent stage lowered the rover. From what i have seen, it barely sunk in the wheels. Which means the wheels and undercarriage are in top condition. Before the landing I had visions of the rover limping around with a bent wheel!

[Mountainsandh]

Originally Posted by jumpjack

is this picture of first laser shot?

Yes Jumpjack, it's the pic that goes with Sheddweller's update from Nasa above.

8mm hole but they can tell so much with that ! hopefully the discoveries will be easy enough to understand for a non-scientific person like me... and this one's only a test. Actually the square is 8mm so the hole must be even tinier, I'm sure size is mentioned somewhere...

[shedweller]

Going by the pic above i would guess that the hole created by the laser is about 0.5mm wide. I must emphasise "about"!!
I don't think i'm too far off though. It's less than 1mm.

[Jawgap]

From the BBC -

Rover panorama: Begin exploring Mars

"This is an interactive impression of the Curiosity rover and its Gale Crater landing site. It is built from a range of image sources, including early black and white images sent back to Earth by the one-tonne robot. One of the key landmarks, Mount Sharp, was constructed using this image."

[shedweller]

Robotic arm has been extended!


Only have thumbnails for now.

[shedweller]

A little extra information for you info geeks:
http://www.nasa.gov/mission_pages/ms.../PIA13388.html

The titanium arm has two joints at the shoulder, one at the elbow and two at the wrist. Each joint moves with a cold-tolerant actuator custom-built for the mission.
That toolkit, MAHLI, with a mass of about 33 kilograms (73 pounds), will include a percussive drill; a magnifying-lens camera; an element-identifying spectrometer; a rock brush; and mechanisms for scooping, sieving and portioning samples.

It's a big lump of stuff at the end of a rather long robotic arm so i hope the actuators are up to the job.

[jaykay74]

Wiggle in the gravel

This set of images shows the movement of the front left wheel of NASA's Curiosity as rover drivers turned the wheels in place at the landing site on Mars. Engineers wiggled the wheels as a test of the rover's steering and anticipate embarking on Curiosity's first drive in the next couple of days. This image was taken by one of Curiosity's Navigation cameras on Aug. 21.

http://www.nasa.gov/mission_pages/ms.../pia16087.html

[shedweller]

[shedweller]

Hard to tell if the shadow movement is due to movement of the rover, movement of the sun or both. It's the back wheel too, isn't it?

[shedweller]

MAHLI extended. Not that anyone needs telling!