Free Republic
Browse · Search
News/Activism
Topics · Post Article

Skip to comments.

Spirit's landing more dramatic than first thought
Spaceflight Now ^ | 1/13/04 | William Harwood

Posted on 01/13/2004 4:41:54 PM PST by LibWhacker

In the end, it was probably just as well flight controllers couldn't watch the Spirit lander's hair-raising descent to the rocky floor of Gusev Crater January 3. Even a base-jumping skydiver might have experienced a jolt of fear given the last-second maneuvers required to turn a high-speed impact into a safe, if bumpy, landing.


An artist's concept of retrorockets firing
just before touchdown. Credit: NASA/JPL/

Plunging toward Mars at 920 mph, Spirit's parachute deployed at an altitude of just 4.6 miles - a mile lower than expected - and its braking rockets fired a scant 34 stories or so above the surface in a flawless, but hair-raising descent that engineers are just now coming to fully appreciate.

The parachute deployed later than predicted because of a dust storm on the other side of the planet that affected the density of the atmosphere above Spirit's landing site. Engineers had instructed the lander's computer to take that into account, but they were surprised at the magnitude of the adjustment.

"It did it just right, but because of the very interesting atmosphere at Gusev at the time we landed, as a result of the dust storm, (parachute deployment) was about a mile lower than our target altitude, which kind of, as you can imagine, makes things a little bit more exciting toward the ground," quipped Rob Manning, Spirit's entry, descent and landing director.

Coming in at an angle, the lander's actual descent velocity was 152 mph, even with its parachute fully deployed. That's somewhat slower than expected, either due to updrafts or higher-than-expected atmospheric density, but still fast enough to cause white knuckles.

"Just to remind you, at 152 miles per hour, the vehicle was going 30 percent faster than a (free-falling) skydiver," Manning said. "And this was with the parachute open. So we are going very fast. In fact, in our animations, some of the early animations we're working on, you can see the ground coming toward you and you realize robots have nerves of steel. Or copper, as the case may be. It is nerve wracking to see the ground come at you that fast. But it works fine, apparently."

As the spacecraft neared the surface, Manning said, a sudden gust of wind began pushing the lander toward a 650-foot-wide crater. But again, Spirit's computer compensated as programmed, ordering side-firing rockets to ignite, counteracting the unwanted sideways motion.

"We were surprised by the dynamics of the wind," said Manning. As a result, the airbag-enclosed lander was cut free of its support bridle at an altitude of just 28 feet above the surface, more than 10 feet lower than expected.

"Think about that. That's only one-and-a-half airbag diameters," said Manning. "Now that's pretty close."

The lander might have survived even if the side-firing rockets hadn't worked. But it would have been a close thing and the spacecraft might have ended up in the crater. But everything worked flawlessly, the lander hit the ground and bounced 28 times across a distance of nearly 1,000 feet before rolling to a stop 57 second later. Spirit ended up about 820 feet from the crater, which will be its first target once surface exploration begins.


TOPICS: News/Current Events
KEYWORDS: boing; landing; mars; spirit; turass
Navigation: use the links below to view more comments.
first 1-2021-4041-44 next last

1 posted on 01/13/2004 4:41:56 PM PST by LibWhacker
[ Post Reply | Private Reply | View Replies]

To: LibWhacker
Our first moon landing was a lot more exciting than that.
2 posted on 01/13/2004 4:54:41 PM PST by U S Army EOD (When the EOD Technician screws up he is always the first to notice.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: LibWhacker
WOW! There goes the Spirit but by the grace of God!
3 posted on 01/13/2004 4:54:49 PM PST by RoseofTexas (r)
[ Post Reply | Private Reply | To 1 | View Replies]

To: RoseofTexas; blam; bonfire; RadioAstronomer; bonesmccoy; Ernest_at_the_Beach; GeronL; ...
Amen!
4 posted on 01/13/2004 4:57:01 PM PST by Howlin (WARNING: If you post to me, Tard and Buttie Fred are gonna copy & paste it to LP!!!!!!!)
[ Post Reply | Private Reply | To 3 | View Replies]

To: LibWhacker
Evidence of money well spent on navigation hardware and software. Compare potential residual benefit of such an exersize against the blind billions spent on social programs in just the last two decades.
5 posted on 01/13/2004 4:57:16 PM PST by ummark
[ Post Reply | Private Reply | To 1 | View Replies]

To: LibWhacker
Why couldn't they have a camera w/telemetry readings on during the landing?

And a microphone on the gizmo now?

6 posted on 01/13/2004 5:02:58 PM PST by jaz.357 (We should be more open-minded toward people trying to kill us.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Howlin
Did you see the picture yesterday of the skid marks where the parachute dragged? There was a strange colored CURVED anomaly in the middle of the scarred terrain that had all the scientists excited about it.
7 posted on 01/13/2004 5:05:58 PM PST by Carolinamom
[ Post Reply | Private Reply | To 4 | View Replies]

To: LibWhacker
As a rocket guy, I hate those cluster-of-grapes landing devices. But I gotta admit they work and are very cheap.

--Boris

8 posted on 01/13/2004 5:06:41 PM PST by boris (The deadliest Weapon of Mass Destruction in History is a Leftist With a Word Processor)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Carolinamom
No, I didn't. Do you know where I might find it?
9 posted on 01/13/2004 5:07:41 PM PST by Howlin (WARNING: If you post to me, Tard and Buttie Fred are gonna copy & paste it to LP!!!!!!!)
[ Post Reply | Private Reply | To 7 | View Replies]

To: U S Army EOD
I'll betcha space travel is going to be a real nail biter for many years to come. Hope we don't lose our nerve!
10 posted on 01/13/2004 5:08:23 PM PST by LibWhacker
[ Post Reply | Private Reply | To 2 | View Replies]

To: U S Army EOD
"Our first moon landing was a lot more exciting than that."

When you think about it, the moon landing was literally by the seat of their pants. All they had was a joy stick and a window.

11 posted on 01/13/2004 5:09:28 PM PST by DaGman
[ Post Reply | Private Reply | To 2 | View Replies]

To: ummark
. . . money well spent on navigation hardware and software.

I'm in awe that it works as well as it does!

12 posted on 01/13/2004 5:09:40 PM PST by LibWhacker
[ Post Reply | Private Reply | To 5 | View Replies]

To: jaz.357
I don't think the antennae were deployed during any part of the landing. It all had to be uploaded later.

BTW, speaking of microphones, didn't the Viking spacecraft have them? I seem to remember something about that. Hope they have them this time, too.

13 posted on 01/13/2004 5:12:48 PM PST by LibWhacker
[ Post Reply | Private Reply | To 6 | View Replies]

To: boris
Speaking from an Alaska-centric viewpoint: what are the bags made of that they don't just shatter at 90 below zero like everything else around here?
14 posted on 01/13/2004 5:13:01 PM PST by RightWhale (How many technological objections will be raised?)
[ Post Reply | Private Reply | To 8 | View Replies]

To: boris
Dare to go with new stuff Boris. Dare I say "out of the box.."
15 posted on 01/13/2004 5:13:07 PM PST by ummark
[ Post Reply | Private Reply | To 8 | View Replies]

To: boris
But I gotta admit they work and are very cheap.

They sure do! When NASA first proposed the idea, I thought it was kind of hare-brained, lol.

16 posted on 01/13/2004 5:14:25 PM PST by LibWhacker
[ Post Reply | Private Reply | To 8 | View Replies]

To: Carolinamom
Where are the parachutes, btw? I'd think they would be visible in that 360 degree panoramic composite they released.
17 posted on 01/13/2004 5:16:42 PM PST by LibWhacker
[ Post Reply | Private Reply | To 7 | View Replies]

To: Howlin
I saw it on TV last night, don't even remember what channel. It looked like another press conference so perhaps it was C-SPAN. They said that it was one of their most exciting discoveries although they didn't know quite what to make of it. It looked like a large inverted and vertical comma and was whitish and greenish in color, unlike the orange-like dirt around it. They said it did not appear to be mud but there was evidently some unknown binding agent.
18 posted on 01/13/2004 5:17:03 PM PST by Carolinamom
[ Post Reply | Private Reply | To 9 | View Replies]

To: DaGman
But they weren't flying it because they couldn't see, some guy on the ground was flying it. Check it out.
19 posted on 01/13/2004 5:18:21 PM PST by U S Army EOD (When the EOD Technician screws up he is always the first to notice.)
[ Post Reply | Private Reply | To 11 | View Replies]

To: LibWhacker
I don't know. Only saw the skid mark of the parachute that they had a photograph of and were so excited about. No mention that I heard as to the location of the parachute.
20 posted on 01/13/2004 5:19:06 PM PST by Carolinamom
[ Post Reply | Private Reply | To 17 | View Replies]


Navigation: use the links below to view more comments.
first 1-2021-4041-44 next last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
News/Activism
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson